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December 2009 CLASSIFICATION DEFINITIONS 95 - 1

December 2009

CLASS 95, GAS SEPARATION: PROCESSES

SECTION I - CLASS DEFINITION

This class provides for processes involving steps result-ing in separation of a gas from a fluid mixture compris-ing (i) a gas and solid or liquid particles entrainedtherein, (ii) a liquid and gas entrained therein, or (iii) aplurality of gases. As a general rule for this class, theremust be a relationship of process steps embracing: (a)inflow of the fluid mixture to be treated, (b) a step orsteps effective to cause the separation into constituentparts, and (c) an outflow of at least one constituentwhich is separate and distinct from the outflow ofanother constituent, including outflow of a constituentby removing the separating medium itself. The gas sepa-ration for this class is effected by processes other thanchemical reaction.

The basic subject matter of this class is of a subcombi-national nature and may include only such ancillary pro-cess steps (e.g., fluid handling, etc.) as are necessary toperfect the gas separating function. Significant inclusionin a claim of features beyond merely perfecting the gasseparating function indicates classification in a morecomprehensive class. Thus, the combination of a gasseparation process of this class and any cleaning orregenerating of the separation media is properly in thisclass, because the cleaning or regenerating is perfectingthe gas separating function. Generally, however, themere naming of an art process in a claim to gas separa-tion does not affect classification. Thus, a claim to filtra-tion of a gas from a named source with no details of thatsource is proper for this class.

(1) Note. The gas separation processes for thisclass generally involve the use of physicalchemistry, chromatography, solid sorption,gas and liquid contact, gas contact, electri-cal fields, magnetic fields, wave energy,selective diffusion, filtration, deflection, orother mechanical means. (Also see Lineswith Other Classes, below.)

(2) Note. This class also provides for processesin which the fluid mixture is treated tochange its make-up, but no real separationoccurs, provided no other suitable classifi-cation exists. Accordingly, in this class arefound processes of using “spark arresters,”which merely change the size of particlesentrained in a gas. These devices are usu-ally deflectors or screens. The processes ofusing them are included in this class

because of their similarity to processeswhich actually separate the fluid mixtureinto constituent parts. Similarly, agglomer-ation, which by itself may not separate par-ticles entrained in a gas, but cause smallparticles entrained therein to join togetheror coalesce to form larger particles, is inthis class unless basis for other classifica-tion exists.

SECTION II - LINES WITH OTHER CLASSESAND WITHIN THIS CLASS

The gas separation processes for this class generallyinvolve the use of physical chemistry, chromatography,solid sorption, gas and liquid contact, gas contact, elec-trical fields, magnetic fields, wave energy, selective dif-fusion, filtration, deflection, or other mechanical means.See the class search note in section III for Class 423,Chemistry of Inorganic Compounds, for the line con-cerning the processes in which the gas separation iscaused by a chemical reaction. Also, see the class searchnote in section III for Class 588, Hazardous or ToxicWaste Destruction or Containment, for the line concern-ing the processes in which the gas separation is causedby destruction or permanent containment of the hazard-ous or toxic waste.

Degassing or purging processes for the removal of a gasfrom a solid will be placed in the class where the solid iseither manufactured or treated. The removal of a gasfrom a solid sorbent (i.e., regeneration), per se, will befound in Class 502, Catalyst, Solid Sorbent, or SupportTherefor: Product or Process of Making. However, theuse of a solid sorbent to separate a gas from a fluid mix-ture and the removal of the gas from the solid sorbent(i.e., regeneration) will be found in this class. For theremoval of a gas from a solid, where the solid is notidentified, see Class 134, Cleaning and Liquid ContactWith Solids.

The Search Notes below also contain lines with otherclasses.

SECTION III - REFERENCES TO OTHERCLASSES

SEE OR SEARCH CLASS:29, Metal Working, appropriate subclasses

indented under subclass 592, particularly sub-class 896.62 for processes of mechanical man-ufacture for making a filter.

95 - 2 CLASSIFICATION DEFINITIONS December 2009

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34, Drying and Gas or Vapor Contact With Solids, appropriate subclasses for generic processesfor separating liquids from solids (i.e., drying)and the contacting of solids with either gases orvapors. Class 95 takes the separation of a gasfrom a fluid mixture in combination with theregeneration of the separating media by dryingor by gas or vapor contact.

47, Plant Husbandry, appropriate subclasses forprocesses of separation of a gas from a fluidmixture by use of a plant of higher order.

48, Gas: Heating and Illuminating, appropriatesubclasses for processes for the manufacture ofheating and illuminating gases.

60, Power Plants, subclasses 273-274 for pro-cesses of treating or handling the materials dis-charging from the combustion chamber of aninternal combustion engine.

62, Refrigeration, appropriate subclasses for pro-cesses peculiar to removing heat from a sub-stance, usually by a change of phase of acoolant or refrigerant and for processes involv-ing subject matter for Class 95 combined witha significant refrigeration step. Examples ofsignificant refrigeration are: (i) expansion of agas through an orifice whereby cooling iseffected to condense any of the constituents ofthe gas by such temperature reduction; (ii) asignificant physical relationship or arrange-ment between elements of a refrigeration cir-cuit (e.g., two related refrigeration coils,detailed description of the circuit, etc.); (iii)change of phase of a coolant or refrigerant (i.e.,evaporation, melting, or sublimation) wherebycooling is effected to condense any of the con-stituents of the gas by such temperature reduc-tion. Some examples of what may be found inClass 62 are: (a) separation of a constituentfrom a plurality of gases by a significantlyclaimed refrigeration step or apparatus; (b)condensation of moisture from the atmosphereas a result of a refrigeration operation; (c) gasdrying by sorption followed by contacting thedried gas with a liquid to produce cooling byevaporation; (d) a refrigerated enclosure com-bined with sorption means; (e) refrigerationproducing processes and apparatus combinedwith steps or means for drying the refrigerant;and (f) extracting a constituent from a pluralityof gases by liquefaction and separation (e.g.,fractionation or distillation, etc.). Class 95takes gas separation of general application,including cooling of the sorbent or cooling ofgas, but not including evaporative cooling after

sorption of the type noted in (c) above. Class95 takes the cold wall-hot wall thermal diffu-sion or repulsion type of separation, regardlessof any refrigeration claimed. Class 95 alsotakes expansion through an orifice of a liquidand gas entrained therein where the gas isremoved from the liquid through the loweringof the pressure and the cooling effect whichinherently results from such pressure reductionis not transferred through a wall to anothermaterial; if such heat transfer occurs, classifi-cation in Class 62 is proper.

73, Measuring and Testing, subclasses 23.2-31.07for gas analysis, per se, and also the combina-tion of gas separation and significant gas analy-sis. The combination of gas separation and anominal step of “analyzing” or “detecting”without further detail of the analysis or detec-tion is insufficient to cause a patent to beplaced in Class 73; that patent will be placed inClass 95. Also, if there is feedback from theanalytical apparatus to control or effect achange in the gas separating operation, thenclassification is in Class 95.

75, Specialized Metallurgical Processes, Composi-tions for Use Therein, Consolidated MetalPowder Compositions, and Loose Metal Partic-ulate Mixtures, appropriate subclasses for pro-cesses for the treatment of liquid or vaporousmetal. See subclass 405 for removal of gasfrom liquid metal by use of a gas permeablemembrane and subclasses 407-412 for filteringvaporous metal.

96, Gas Separation: Apparatus, appropriate sub-classes for the corresponding apparatus to theprocesses of Class 95. When a patent has aclaim or claims to a Class 95 process and aclaim or claims to a Class 96 apparatus, thepatent will be placed as an original in Class 95,even though there may be an apparatus claimthat is more comprehensive than a processclaim.

128, Surgery, subclasses 200.24 through 207.18 formethods of supplying a breathable gas to, orexhausting such gas from, a living body. Sub-class 200.24 and the subclasses mentionedbelow require that the method be adapted foruse on or in the living body and also includediagnostic or therapeutic methods when theonly disclosed utility is for diagnosis or treat-ment of a living body. See especially subclass200.25 for an artificial gill or means for sepa-rating entrained air from a liquid stream; sub-class 201.25 for a respiratory device including


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body or head supported means covering user’sscalp and means for removing a substance fromrespiratory gas; subclass 204.16 for removal ofa substance from respiratory gas by cooling;subclass 205.12 for means for supplying respi-ratory gas under positive pressure includingmeans for removing a substance from the respi-ratory gas; and subclass 205.27 for a respira-tory device including means for removing asubstance from respiratory gas.

137, Fluid Handling, appropriate subclasses forcombinations of fluid handling and gas separa-tion involving more than mere flow control toor from the separating means. (a) For classifi-cation in either Class 137 or Class 95, whereboth the fluid handling and gas separation areincluded in the combination, classification willbe based upon the ultimate purpose of the sub-ject matter and not upon the ancillary or subor-dinate feature of the combination consistentwith the objects and aims therefor (e.g., it is notintended that the inclusion of filtering, no mat-ter how specifically defined, will be sufficientto carry a “gas field storage and distributionprocess” to Class 95 whether the filtering pro-tects the apparatus used in the process or is thelast step in the process). The fluid handling forClass 95 should be no more than that necessaryto convey or conduct the fluid mixture to, at, oraway from the point of separation. (b) Class137 also takes separation of gases from gases,liquids, or solids by gravity only (i.e., where nospecific means is claimed for effecting the sep-aration).

140, Wireworking, subclasses 3 through 57 for wirefabric making.

141, Fluent Material Handling, With Receiver orReceiver Coacting Means, subclasses 4through 8 for processes of transferring fluentmaterial through a flow confining system, thesource and receiver parts of which are normallyseparable, including varying gaseous condi-tions (e.g., causing a vacuum, etc.) in thereceiver.

156, Adhesive Bonding and Miscellaneous Chemi-cal Manufacture, appropriate subclasses forprocesses there classified for adhesively bond-ing and otherwise manufacturing filters.

165, Heat Exchange, appropriate subclasses for pro-cesses where only indirect heat exchange isinvolved and especially subclasses 201-265and 58-66 for heating and cooling includingaddition or removal of water vapor from air.

Cold wall-hot wall thermal diffusion processeswill be found in Class 95, subclass 289.

166, Wells, appropriate subclasses for processesinvolving shafts or deep borings in the earth forthe extraction of fluids from the earth. Seeespecially subclasses 265 through 267 for pro-cesses involving separating material leavingthe well. A gas separation process including anominal recitation of a well process is properfor Class 95. For classification in Class 166,some details specific to a well process shouldbe recited for the combination of a gas separa-tion process and a well process. However, inthe situation in which one of the constituentsseparated is inserted into an input well, a merebroad recitation of such well process is suffi-cient for classification in Class 166.

203, Distillation: Processes, Separatory, subclasses39 through 48 for processes for separating aliquid mixture (distilland) by vaporizing andcondensing at least a portion thereof to isolatein the condensed liquid (distillate) or in theunvaporized portion (residue) a comparativelypure compound combined with subjecting thevapor to a disparate physical treatment toremove a substance. For Class 203, the liquidmixture (distilland) must have a boiling pointabove 0°C under normal atmospheric pressure(760 mm Hg).

204, Chemistry: Electrical and Wave Energy,appropriate subclasses for processes in which achemical change is brought about by the appli-cation of an electric current or wave energy tomaterial being treated wherein more than themere thermal effect of the current or energy isinvolved and subclasses 554 through 573 forprocesses for the separation or purification ofliquids by the physical or physical-chemicalaction of an electrical stress. See particularlysubclass 157.3 for processes in which an initialnormally gaseous mixture is treated by waveenergy so as to remove therefrom by a chemi-cal reaction or change to a different chemicalform at least one of the components therein.

208, Mineral Oils: Processes and Products, appro-priate subclasses for processes for the recoveryor treatment of naturally occurring mineral oilwhich result in the production of a purified ormodified mineral oil. See particularly subclass310 for the separation of mineral oils intohydrocarbon fractions, at least one of which isa mineral oil, wherein a mineral oil containingfluid mixture is contacted with a solid materialwhich selectively adsorbs a mineral oil fraction


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from the fluid mixture. See also subclass 340for the recovery of liquid mineral oils from nat-ural gases or from uncondensed gas-vapor mix-tures obtained from a mineral oil conversionoperation including separation of mineral oilsinto hydrocarbon fractions, at least one ofwhich is a mineral oil. Processes which involvea gas separation procedure classifiable in Class95 followed by the recovery of a mineral oil byname only (e.g., reciting only rectification,vacuum pressure or flash distillation, etc.) areclassified in Class 95. Processes wherein themineral oil recovery step includes any detailsthereof or includes some subsequent treatmentof the separated mineral oil are classified inClass 208.

209, Classifying, Separating, and Assorting Solids,subclasses indented under subclasses 21 and133 that include “deposition” in their titles forprocesses for the separating and segregatinginto grades components of solid mixturesemploying a gaseous suspending mediumwhich is separated from the solids.

210, Liquid Purification or Separation, appropriatesubclasses for the separation of a constituentfrom a flowable liquid mixture; except for theseparation of a gas initially present in a liquidmixture. Class 210 is superior to Class 95 andtakes separating processes, per se, genericallydisclosed or claimed as fluid separation or ifthe disclosure or a claim is restricted to liquidseparation. Class 210 also takes processeswhich remove or vent gas formed incidentallyto the handling of the fluid mixture or as aresult of a Class 210 treatment (see particularlysubclasses 603, 640, 664, 718, and 750). How-ever, Class 95 takes processes operating toremove gas initially present in an inflowing liq-uid mixture, with or without liquid separation.The removal of a volatile organic compound(e.g., ethanol (C2H5OH), gasoline, etc.) from aliquid is not taken to be degasification of a liq-uid for Class 95 when the volatile organic com-pound is initially present as a liquid mixed withanother liquid. The removal of a volatileorganic compound from a liquid may be foundin Class 210 for liquid purification or separa-tion or Class 203 for separatory distillation pro-cesses. Class 95 will also take a processincluding a liquid separation step in a Class 95operation (e.g., regenerating a scrubbing liquidin a gas scrubbing operation, etc.).

241, Solid Material Comminution or Disintegration, subclasses 18 through 19 for processes forcombinations of comminution and separationof solids from a gas. Class 241 is superior tothe material separation classes and, therefore,provides for processes in which comminutionis combined with steps to separate the materialinto classes according to the physical charac-teristics of its components before, during, orafter the comminuting operation. Class 95takes processes, such as deflection or the like,that may act to comminute material as a sec-ondary or incidental function of what is basi-cally a holding back or separating procedure(e.g., disintegration or attrition of ignited parti-cles in spark arresters, etc.). Such processes areclassified on the basis of their essential func-tion in Class 95.

250, Radiant Energy, subclasses 282 through 284 for methods for the ionic separation of materi-als utilizing the charge-to-mass ratios of parti-cles. These methods may be for subjecting theionized particles to the effects of an electric ormagnetic field, which causes the particles totravel through a curved trajectory, the particlesof a certain charge-to-mass ratio having a tra-jectory different from those particles havingother charge-to-mass ratios.

252, Compositions, subclasses 189 through 192 forsubstances (e.g., liquid sorbent compositions,etc.) for use in absorbing or binding carbonmonoxide (CO), sulfur (S), negative elements,or acids; subclass 193 for substances (e.g., liq-uid sorbent compositions, etc.) for use inabsorbing or binding ammonia, alkalis, or otherbases; and subclass 194 for substances (e.g.,liquid sorbent compositions, etc.) for use inabsorbing or binding water.

261, Gas and Liquid Contact Apparatus, appropri-ate subclasses for apparatus for degasifying liq-uid (e.g., deaerating feed water heater, etc.)wherein the liquid is merely contacted with agas in a chamber or space for deaerationthereof; for apparatus wherein a gaseous fluidmixture is contacted with a liquid spray, sheet,stream, or bath to precipitate dust or to sorb aconstituent from the gaseous fluid mixture; forapparatus comprising a nonabsorbent elementon which a gaseous fluid mixture is contactedwith a liquid if the element is continuouslysupplied with a liquid or is continuously movedinto and out of a liquid bath or supply; and forapparatus comprising an absorbent poroussheet or mass on which a gaseous fluid mixture


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is contacted with a liquid if the sheet or massis: (a) continuously supplied with liquid, (b)cyclically or periodically moved through a liq-uid reservoir, (c) maintained wet by liquidapplying means, or (d) moistened by maintain-ing some part of a continuous wick type mem-ber immersed in liquid, by following the law ofthe machine, or during normal operation of agas contacting function. Note that under theprovisions of (a) and (b) there must be no affir-mative means to dry the sheet or mass, normeans to assure a dry condition of the sheet ormass before gas flow is resumed or the sheet ormass is returned to the gas contacting position.If apparatus for degasifying liquid by contactwith a gas has other means to cause gas separa-tion of the liquid with gas entrained therein, ofthe separated gas, or of the separated liquid,then the apparatus is classified in Class 96. Ifapparatus in which a gaseous fluid mixture iscontacted with a liquid to precipitate dust or tosorb a constituent from the gaseous fluid mix-ture has other means to cause gas separation orhas means to treat the contact liquid, then theapparatus is classified in Class 96.

(1) Note. Apparatus for separating ammonia(NH3) or acid anhydrides (CO2, SO2, etc.)from a gas by mere contact with a liquid isclassified in Class 261.

(2) Note. Processes for gas separation by con-tacting a gaseous fluid mixture with a liquidand processes of degasifying a liquid areclassified in Class 95.

376, Induced Nuclear Reactions: Processes, Sys-tems, and Elements, for processes for inducednuclear reactions combined with steps for reac-tion product treatment. See particularly sub-classes 146 through 148, 189, 195, 198, and201. See subclasses 308-316 for processesincluding fission reactor material treatment.

406, Conveyors: Fluid Current, subclasses 154through 180 for processes to convey solidmaterial in a fluid current with separation ofthe solids from the fluid at the conveyor outlet.

422, Chemical Apparatus and Process Disinfecting,Deodorizing, Preserving or Sterilizing, sub-class 4 for processes of acting on a gas formaintaining a protective environment or coun-teracting a destructive environment by disin-fecting, deodorizing, preserving, or sterilizing.The deodorizing for Class 422 generallyinvolves adding a substance to a gas to mask an

odor. Class 95 takes deodorizing a gas thatinvolves gas separation of the type that meetsthe requirements for gas separation in the defi-nition for Class 95. Class 422 is the residualplace for deodorizing a gas that does not meetthe requirements of the definitions for Class 95or Class 423.

423, Chemistry of Inorganic Compounds, sub-classes 210 through 215.5 for gas separationmethods relying upon a chemical reaction(including combustion). However, for a Class95 process including a chemical reaction notinvolved in the separation, per se, see the Class95 Glossary for TREATMENT. A particularchemical must be claimed and the chemicalreaction must be inherent or disclosed for pat-ents to be placed in Class 423. Broadly recitingthe separating material as a “chemical” or as“gas purifying material” does not exclude thepatent from Class 95. Absorption and adsorp-tion are not considered chemical reactions inthis respect. Processes for separating a gaseousfluid mixture having therein ammonia (NH3)or acid anhydrides (e.g., CO2, SO2, etc.) bycontacting the gaseous fluid mixture with waterand thus dissolving these gases out of the gas-eous fluid mixture are in Class 95, notwith-standing the fact that a chemical reactionoccurs in the solution and that ammoniumhydroxide or the acids are formed. Correspond-ing gas and liquid contact apparatus, per se, isclassified in Class 261. See the search classnote for Class 261 in this section for the line.See subclass 658.2 for hydriding an alloy oftwo or more metals and recovering hydrogenfrom the hydride.

435, Chemistry: Molecular Biology and Microbiol-ogy, appropriate subclasses for processes ofusing a micro-organism or enzyme to synthe-size a chemical product and for processes oftreating a material with a micro-organism orenzyme to separate, liberate, or purify a preex-isting substance. See particularly subclass 266for processes of treating a gas, emulsion, orfoam with an enzyme or immobilized enzymeor micro-organism or plant or animal cells toisolate or recover a preexisting substancewhich is chemically unchanged by the process.

494, Imperforate Bowl: Centrifugal Separators, appropriate subclasses for processes for thebreaking up or subdividing of material, whichmaterial comprises a mixture of fluids or fluentsubstances, into two or more components by


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utilizing a rotatable, receptaclelike memberhaving a generally solid wall, and commonlytermed a bowl, for subjecting the material tocentrifugal force. Thus, gas separation pro-cesses that use an imperforate bowl, centrifugalseparator are proper for Class 494.

502, Catalyst, Solid Sorbent, or Support Therefor:Product or Process of Making, subclasses 20through 56 for regenerating or rehabilitatingsolid sorbent compositions, per se, subclasses60-87 for zeolite compositions and for pro-cesses of making zeolite compositions, andsubclasses 400-438 for other solid sorbentcompositions and for processes of making solidsorbent compositions. Class 95 will take thecombination of gas separation using a solidsorbent composition and regenerating or reha-bilitating the solid sorbent composition.

516, Colloid Systems and Wetting Agents; Subcom-binations Thereof; Processes of Making, Stabi-lizing, Breaking, or Inhibiting, appropriatesubclasses for colloid systems or agents forsuch systems or making or stabilizing such sys-tems or agents, appropriate subclasses for pro-cesses of or compositions for orsubcombination compositions for the breakingof or inhibiting of colloid systems (subclasses115 through 134 for defoaming); in eachinstance, when generically claimed or whenthere is no hierarchically superior provision inthe USPC for the specifically claimed art.

585, Chemistry of Hydrocarbon Compounds, sub-classes 800 through 868 for processes in whicha mixture of a hydrocarbon compound withanother substance is treated to recover thatsame compound in a more usable condition,that is, a purer or more desirable condition, bya treatment which comprises separating thehydrocarbon from the other substance or mak-ing the other substance less noxious.

588, Hazardous or Toxic Waste Destruction or Con-tainment, appropriate subclasses for non-gas-eous hazardous or toxic waste destruction byany chemical means, including heating, chemi-cal agents, or the interaction with any form ofradiation to cause a chemical change whichresults in an environmentally safe substance.Class 588 provides for the destruction of gas-eous chemical warfare agents, and includes gasseparation when it is incidental to the destruc-tion of non-gaseous hazardous or toxic waste.

SECTION IV - GLOSSARY

DETECT

The term “detect,” which is used in many of the controlsubclasses, is used in both a quantitative and a qualita-tive sense. This means that a definite measurement of aprocess variable is made (e.g., temperature, pressure,concentration, etc.) or that the presence of a particularevent is determined (e.g., presence of sparking, changein liquid level determined by position of float, etc.).

FILTER

An article or mass of material made of closely spaced orintimately arranged intermeshed or unconnected fibers,elements, strands, or particles that collectively act as abarrier to physically retain at least one constituent of afluid mixture on its surfaces or in the spaces between thefibers, elements, strands, or particles while permittingpassage of the remaining constituents.

A filter has no “chemical” affinity for a constituent of afluid mixture. The retention of the constituent by the fil-ter depends upon a mechanical entrapment of solid orliquid particles because of their relatively large sizecompared with the interstices or spaces between indi-vidual fibers, elements, strands, or particles. Theretained particles can be removed by brushing, wiping,shaking, or similar mechanical action.

FLUID MIXTURE

The phrase “fluid mixture” is used throughout the defi-nitions to mean (a) a gas and solid or liquid particlesentrained therein, (b) a liquid and gas entrained therein,or (c) a plurality of gases.

GAS

Matter of very low density and viscosity, relatively greatexpansion and contraction with changes in pressure andtemperature, that is readily diffusive, with a tendency toexpand indefinitely, with molecules in free movement.The term “gas” includes “vapor” (q.v.).

GASEOUS FLUID MIXTURE

The phrase “gaseous fluid mixture” is used throughoutthe definitions to mean (a) a gas and solid or liquid par-ticles entrained therein or (b) a plurality of gases.

LIQUID SORBENT

A liquid capable of retaining part of a fluid mixture with


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which it is contacted. The action in most cases is that ofselective retention (i.e., the sorbent removes only thatpart of the fluid mixture for which it has the greatestaffinity).

REGENERATION

Restoration of the separatory material to the condition itwas in before the separatory process.

SEPARATING APPARATUS

The entire gas separating means, which consists of all ofthe apparatus parts related to gas separation andincludes apparatus parts that are in addition to the sepa-rator.

SEPARATING MEDIUM (MEDIA)

Liquid sorbent or means that effects the separation intoconstituent parts (e.g., deflector, filter, molecular sieve,sorber, etc.). (Media has been used in the singular and inthe plural.)

SEPARATOR

The portion of the apparatus that consists of a separatingmedium and the structure supporting, retaining, or sub-stantially confining the separating medium.

SOLID SORBENT

A solid sorbent is a solid material which separates aconstituent (e.g., a gas, vapor, etc.) from a fluid mixturecontaining such constituents in a “quasi-chemical” man-ner. The action in most instances is that of selectiveretention (i.e., the sorbent removes only the part of thefluid mixture for which it has the greatest affinity). Theretained constituent cannot be removed by shaking,brushing, or similar mechanical action, but generallycan be removed by heating, pressure reduction, or use ofa stripping or denuding fluid.

TREATMENT

(a) With respect to the class subject matter, the term isrestricted to reversible and nonchemical changes inphysical characteristics of the fluid mixture or a sepa-rated constituent (e.g., heating, cooling, humidity con-trol, agitating, pressure regulation, etc.). (b) Withrespect to the media used to perform the gas separationor to a material used to condition the fluid mixture forseparation, the term may include chemical preparation,reconditioning, or reaction.

VAPOR

The gaseous state of matter that is liquid or solid under atemperature of 0°C and 760 mm Hg pressure.

SUBCLASSES

1 WITH CONTROL RESPONSIVE TOSENSED CONDITION:This subclass is indented under the class defini-tion. Process in which the separation is regu-lated by detecting a characteristic or a changein a characteristic of the process and by imple-menting an action in the process based uponthe detected characteristic or change therein.

(1) Note. In this subclass and the subclassesindented hereunder, a single means maybe used both to detect the characteristicor the change in the characteristic in theprocess and to implement an action inthe process based upon the detectedcharacteristic or change therein. Theremust be a positive action made by themeans because of the detected character-istic or change therein. An example isthe use of a pressure relief valve inwhich a certain pressure must be reachedbefore the valve opens to relieve the highpressure in the process. Another exampleis the use of a bimetallic element in athermostat in which a certain tempera-ture must be reached before a switch istripped in order to control the tempera-ture in the process. A third example isthe use of increased weight on a separat-ing media because of accumulation of aseparated constituent to cause the sepa-rating media to move to a position ofnonuse or regeneration. Excluded fromthis subclass and the subclasses indentedhereunder are processes in which there isno positive action made by the singlemeans because of the detected character-istic or change therein. An example of aprocess which is excluded and placedbelow is the flow of liquid over a baffleonce the liquid level reaches the top ofthe baffle.


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SEE OR SEARCH CLASS:73, Measuring and Testing, subclasses

23.2 through 31.07 for gas analysis,and see the class definition of Class95 for a statement of the line.

96, Gas Separation: Apparatus, sub-classes 18 through 24 for electricalseparation apparatus with controlmeans responsive to sensed condition;subclass 102 for chromatographyapparatus with control means respon-sive to sensed condition; subclasses109-114 for solid apparatus with con-trol means responsive to sensed con-dition; subclasses 156-174 fordegasifying means with control meansresponsive to sensed condition; sub-classes 397-412 for gas separationapparatus with automatic controlmeans for gas or nongaseous constitu-ent discharge; and subclasses 417-423for gas separation apparatus with sig-nals, indicators, measuring, or testingmeans.

2 Electric or electrostatic field (e.g., electro-static precipitation, etc.):This subclass is indented under subclass 1.Process in which there is a step including dis-charge of an electric current into the fluid mix-ture or electrifying a fluid or solid that contactsthe fluid mixture.

SEE OR SEARCH THIS CLASS, SUB-CLASS:57 through 81, for processes using elec-

tric or electrostatic fields without con-trol responsive to a sensed condition.

SEE OR SEARCH CLASS:96, Gas Separation: Apparatus, sub-

classes 18 through 24 for electricalseparation apparatus with controlmeans responsive to sensed condition.

3 Concentration sensed:This subclass is indented under subclass 2.Process in which concentration of a constituentpresent in the process or a change therein (e.g.,dust, humidity, etc.) is detected and is used tocontrol some aspect of the process.

4 Temperature sensed:This subclass is indented under subclass 2.Process in which temperature or a changetherein is detected and is used to control someaspect of the process.

5 Sparking sensed:This subclass is indented under subclass 2.Process in which the presence or frequency ofsparking in the gas phase, often accompaniedby short bursts of increasing current flow ordecreasing electrode voltage, is detected and isused to control some aspect of the process.

6 Current sensed:This subclass is indented under subclass 2.Process in which current flowing between dis-charge and collector electrodes or a changetherein is detected and is used to control someaspect of the process.

7 Voltage sensed:This subclass is indented under subclass 2.Process in which voltage applied, eitherdirectly to an electrode or indirectly to the fluidmixture, or a change therein is detected and isused to control some aspect of the process.

8 Concentration sensed:This subclass is indented under subclass 1.Process in which concentration of a constituentpresent in the process or a change therein (e.g.,pH, humidity, dust content, etc.) is detected andis used to control some aspect of the process.

9 pH sensed:This subclass is indented under subclass 8.Process in which pH or a change therein isdetected and is used to control some aspect ofthe process.

10 Humidity sensed:This subclass is indented under subclass 8.Process in which humidity or a change thereinis detected and is used to control some aspectof the process.

11 Flow of fluid mixture to sorber stopped ordiverted to other equipment, or sorbentregenerated:This subclass is indented under subclass 8.Process in which the flow of the fluid mixtureto a sorber is stopped or the flow of the fluid


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mixture is switched to another sorber basedupon the detected concentration or changetherein; or process in which a sorbent is regen-erated based upon the detected concentration orchange therein.

12 Gas flow rate modified:This subclass is indented under subclass 8.Process in which flow rate of a gas is changedbased upon the detected concentration orchange therein.

13 Sorbent flow rate modified:This subclass is indented under subclass 8.Process in which flow rate of a sorbent ischanged based upon the detected concentrationor change therein.

14 Temperature sensed:This subclass is indented under subclass 1.Process in which temperature or a changetherein is detected and is used to control someaspect of the process.

15 And pressure sensed:This subclass is indented under subclass 14.Process in which pressure or a change thereinis also detected and is used to control someaspect of the process.

16 Modification of flow rate of liquid which isadded to gas:This subclass is indented under subclass 14.Process in which flow rate of liquid which isadded to a gas is modified based upon thedetected temperature or change therein.

17 Cooling:This subclass is indented under subclass 14.Process in which the fluid mixture, a separatedconstituent, or an apparatus involved in theprocess is cooled based upon the detected tem-perature or change therein.

18 Heating:This subclass is indented under subclass 14.Process in which the fluid mixture, a separatedconstituent, or an apparatus involved in theprocess is heated based upon the detected tem-perature or change therein.

19 Pressure sensed:This subclass is indented under subclass 1.Process in which pressure or a change thereinis detected and is used to control some aspectof the process.

20 Apparatus cleaned:This subclass is indented under subclass 19.Process in which apparatus is cleaned basedupon the detected pressure or change therein.

21 Sorbent regenerated:This subclass is indented under subclass 19.Process in which a sorbent is regenerated basedupon the detected pressure or change therein.

22 Gas flow rate modified:This subclass is indented under subclass 19.Process in which flow rate of a gas is changedbased upon the detected pressure or changetherein.

23 Gas flow rate sensed:This subclass is indented under subclass 1.Process in which gas flow rate or a changetherein is detected and is used to control someaspect of the process.

24 Liquid level sensed:This subclass is indented under subclass 1.Process in which liquid level or a changetherein is detected and is used to control someaspect of the process.

25 WITH RECORDING OR SIGNALINGCONDITION:This subclass is indented under the class defini-tion. Process in which a characteristic or achange in a characteristic of the fluid mixture,of a separated constituent, or of apparatus usedin the process is set down for preservation inpermanent form or is indicated by means giv-ing information of an audible or a visual nature(e.g., alarm, etc.).


23.2 through 31.07 for gas analysisand see the class definition of Class95 for a statement of the line.


1December 2009

26 WITH TIMING OF OPERATION:This subclass is indented under the class defini-tion. Process in which the time at which anoperation occurs is controlled or the length oftime in which an operation is performed is con-trolled.

27 MAGNETIZED PARTICLE BED:This subclass is indented under the class defini-tion. Process in which magnetic lines of forceare applied to a bed of loose particles that con-tain a magnetizable component.

(1) Note. The application of magnetic linesof force to a magnetizable particle bedmay be to stabilize the bed, to preventback-mixing, or to control porosity ofthe bed.

28 MAGNETIC SEPARATION:This subclass is indented under the class defini-tion. Process in which the separation is causedor aided by magnetic lines of force.


classes 1 through 3 for apparatuswhich separates a gas by magneticlines of force.

209, Classifying, Separating, and Assort-ing Solids, subclasses 38, 39, 40, 212,and 213-232 for classifying, separat-ing, and assorting solids using appara-tus of the magnetic type.

210, Liquid Purification or Separation, subclasses 222 through 223 for mag-netic apparatus for purification or sep-aration of a liquid and subclass 695for processes of purifying or separat-ing a liquid using magnetic force.

29 SOUND WAVES USED:This subclass is indented under the class defini-tion. Process in which the separation iseffected or enhanced by the energy of compres-sional vibratory waves in a fluid medium, thewaves being below, within, or above the audi-ble spectrum.

(1) Note. Pressure pulses in a fluid gener-ated merely by intermittent discharge ofa gas are not considered to be compres-sional vibratory waves under this defini-

tion. However, compressional vibratorywaves under this definition may be pro-duced by intermittent discharge of a gas,as in a siren.

SEE OR SEARCH CLASS:55, Gas Separation, subclass 292 for

cleaning means for separating mediaof the sonic type.

96, Gas Separation: Apparatus, subclass389 for gas separation apparatus usingwound waves.

30 Degasification of liquid:This subclass is indented under subclass 29.Process in which the wave energy is used toseparate gas from a liquid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:46, for processes of degasification of a

liquid by selective diffusion of gasesthrough a substantially solid barrier.

156 through 186, for processes of contact-ing a gas with a liquid and degasifica-tion of the contact liquid.

241 through 266, for other processes ofdegasification of a liquid.

31 DIFFERENCE IN MOLECULAR VELOC-ITY, DENSITY, OR MOMENTUM OFGASES USED:This subclass is indented under the class defini-tion. Process in which the plurality of gases isseparated into constituent gaseous parts bymaking use of physical differences in molecu-lar speed, weight, or inertia of the constituentgaseous parts.

SEE OR SEARCH THIS CLASS, SUB-CLASS:267 through 272, for processes of separat-

ing solid or liquid particles from a gasby deflection.

32 Passing gases through nozzle:This subclass is indented under subclass 31.Process in which gaseous constituents havingdifferent molecular weights or different gaskinetic cross sections are separated, with theplurality of gases flowing out of a short tube,usually tapering, that forms the vent of a hoseor pipe in order to effect the separation.


December 2009

33 Directing gas streams toward one another:This subclass is indented under subclass 32.Process in which gas streams or jets aredirected toward one another and are deflected.

34 Centrifugal force:This subclass is indented under subclass 31.Process in which the plurality of gases is sepa-rated by the effect of centrifugal action whichcauses the gases to assume a rapid arcuate orcircular movement, with this movement caus-ing the constituents of the mixture to separateinto more or less distinct layers, dependingupon the density of the constituents.


ing solid or liquid particles from a gasby using centrifugal force.

35 Created by rotating equipment:This subclass is indented under subclass 34.Process in which the centrifugal force is causedby a rotating element moving around an axis.

SEE OR SEARCH THIS CLASS, SUB-CLASS:270, for processes of separating solid or

liquid particles from a gas by usingcentrifugal force created by rotatingequipment.

36 LIQUID-SOLID SLURRY USED:This subclass is indented under the class defini-tion. Process in which the separation is accom-plished by contacting the fluid mixture with apumpable mixture of a solid and a liquid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:92, for a two-step process of solid sorp-

tion and liquid sorption.

37 Organic compound removed from gasThis subclass is indented under subclass 36.Process in which an organic compound isremoved from gas by contact with a liquid-solid slurry.

38 Halogen containing compound removedfrom gas:This subclass is indented under subclass 36.Process in which a halogen (i.e., fluorine (F),chlorine (Cl), bromine (Br), iodine (I), astatine(At)) containing compound is removed fromgas by contact with a liquid-solid slurry.

39 COMPRESSING AND INDIRECT COOL-ING OF GASEOUS FLUID MIXTURE TOSEPARATE:This subclass is indented under the class defini-tion. Process in which the separation of a con-stituent from a gaseous fluid mixture is accom-plished by extracting heat in an indirect heatexchanger before, after, or while increasing thepressure on the gaseous fluid mixture.

(1) Note. The cooling must not involvedetails of a refrigeration process or appa-ratus. See the class definition for the linebetween Class 95 and Class 62.

40 And use of heat absorbing agent:This subclass is indented under subclass 39.Process in which a substance is added to thegaseous fluid mixture to prevent a material risein temperature of the gaseous fluid mixture byabsorbing the heat of compression.

41 And solid sorption:This subclass is indented under subclass 39.Process in which a solid sorbent is used toremove a constituent from the gaseous fluidmixture.

SEE OR SEARCH THIS CLASS, SUB-CLASS:90 through 148, for processes of solid

sorption without compressing andcooling of the gaseous fluid mixturein order to separate.

42 And liquid contact (e.g., scrubbing, sorp-tion, etc.):This subclass is indented under subclass 39.Process in which a liquid is used to remove aconstituent from the gaseous fluid mixture(e.g., scrubbing, sorption, etc.).


1December 2009

SEE OR SEARCH THIS CLASS, SUB-CLASS:149 through 240, for processes of liquid

contact without compressing andcooling of the gaseous fluid mixturein order to separate.

43 SELECTIVE DIFFUSION OF GASES:This subclass is indented under the class defini-tion. Process in which a fluid mixture contain-ing a gas to be separated contacts a solid, liq-uid, or gaseous barrier, with the gas separatingbecause of the differential permeability of thebarrier with respect to the gas.


classes 4 through 14 for apparatus forselective diffusion of gases.

44 Selective diffusion of gases through immobi-lized liquid:This subclass is indented under subclass 43.Process in which a plurality of gases containinga gas to be separated contacts a liquid barrierthat is supported or immobilized in or on aporous medium, with the plurality of gasesbeing separated because of the differential per-meability of the liquid with respect to thegases.

SEE OR SEARCH THIS CLASS, SUB-CLASS:149 through 240, for processes of contact-

ing a fluid mixture with a liquid.

SEE OR SEARCH CLASS:96, Gas Separation: Apparatus, subclass 5

for corresponding apparatus. Patentsare not cross-referenced from Class96, subclass 5 to this subclass basedonly on disclosure. Therefore, rele-vant disclosures of gas separation pro-cesses may be found in the apparatusarea.

45 Selective diffusion of gases through substan-tially solid barrier (e.g., semipermeablemembrane, etc.):This subclass is indented under subclass 43.Process in which a plurality of gases or a mix-ture of gas entrained in a liquid contacts a sub-stantially solid surface (e.g., semipermeable

membrane, etc.) and a gas is separated fromanother gas or a gas is separated from the liquidbecause of the differential permeability of thesurface of the solid with respect to the gases.

(1) Note. Class 95 will take dissociation of agas molecule at the barrier boundarywhen such dissociation facilitates pas-sage of the gas through the barrier; theatoms reconvert to the gas molecule onthe downstream side of the barrier. If thedissociation of the gas occurs away fromthe barrier and a resulting product dif-fuses through the barrier, then the patentwill be in Class 423 for an inorganic gasand in the appropriate organic class foran organic gas.

SEE OR SEARCH CLASS:205, Electrolysis: Processes, Composi-

tions Used Therein, and Methods ofPreparing the Compositions, sub-classes 334 through 639 for pro-cesses using a solid electrolyte mem-brane (SEM) situated between twoelectrodes positioned to apply exter-nal voltage across the membrane.These membranes are used where thepartial pressure of the gas to be dif-fused through the membrane on thefeed side of the membrane is lowerthan that on the permeate side. Mole-cules on the feed side of a cell con-taining a solid electrolyte membraneare electrochemically dissociated intoions on the cathode. The ions are thentransported across the matrix of themembrane by the applied voltage andrecombined to form molecules on theanode. Class 95 takes the use of asolid electrolyte membrane whichfunctions without electrodes and with-out externally applied voltage. Thesemembranes are used where the partialpressure of the gas to be diffusedthrough the membrane on the perme-ate side is lower than that on the feedside. Electrodeless solid electrolytemembrane cells are operated by main-taining a pressure on the feed sidesuch that a positive driving force forion transport can be achieved in theabsence of an externally applied volt-age and power source.


December 2009

210, Liquid Purification or Separation, subclasses 96.2, 257.2, and 321.6-321.9 for apparatus having mem-branes or dialyzers for separating liq-uids, subclasses 500.21-500.43 forsemipermeable membranes used inthe separation of liquids, and sub-classes 634-655 for processes of sepa-rating a liquid by selective diffusionof a component of a liquid through amembrane or septum.

427, Coating Processes, subclasses 245through 246 for methods of coating abase so that the resulting product isforaminous or porous, wherein thecoating includes openings or holeswhich are very small, generallymicroscopic in size.

520, Synthetic Resins or Natural Rubbers,appropriate subclasses for syntheticresins or natural rubbers that may beused for selective diffusion of gases.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 818 through 819for processes in which a liquid hydro-carbon is recovered from a liquid mix-ture containing the hydrocarbon bythe use of selective diffusion througha semipermeable membrane.

46 Degasification of liquid:This subclass is indented under subclass 45.Process in which gas is separated from a liquidby selective diffusion of the gas through a sub-stantially solid barrier.


liquid by use of sound waves.156 through 186, for processes of contact-

ing a gas with a liquid and degasifica-tion of the contact liquid.

241 through 266, for other processes ofdegasification of a liquid.

SEE OR SEARCH CLASS:75, Specialized Metallurgical Processes,

Compositions for Use Therein, Con-solidated Metal Powder Composi-tions, and Loose Metal ParticulateMixtures, subclass 405 for processesof removing gas from liquid metal byuse of a gas permeable membrane.

96, Gas Separation: Apparatus, subclass 6for corresponding apparatus. Patentsare not cross-referenced from Class96, subclass 6 to this subclass basedonly on disclosure. Therefore, rele-vant disclosures of gas separation pro-cesses may be found in the apparatusarea.

210, Liquid Purification or Separation, subclass 640 for processes of separat-ing a constituent from a liquid byselective diffusion of the constituentthrough a membrane or septumwherein the constituent is not initiallypresent as a gas in the liquid andpasses through the membrane or sep-tum in vapor phase.

47 Nitrogen or nitrogen containing compoundpermeates barrier:This subclass is indented under subclass 45.Process in which nitrogen (N2) or a nitrogencontaining compound selectively diffusesthrough a substantially solid barrier.

48 Halogen containing compound permeatesbarrier:This subclass is indented under subclass 45.Process in which a halogen (i.e., fluorine (F),chlorine (Cl), bromine (Br), iodine (I), astatine(At)) containing compound selectively diffusesthrough a substantially solid barrier.

49 Sulfur containing compound permeates bar-rier:This subclass is indented under subclass 45.Process in which a sulfur (S) containing com-pound selectively diffuses through a substan-tially solid barrier.

50 Organic compound permeates barrier:This subclass is indented under subclass 45.Process in which an organic compound selec-tively diffuses through a substantially solidbarrier.

51 Carbon dioxide or carbon monoxide perme-ates barrier:This subclass is indented under subclass 45.Process in which carbon dioxide (CO2) or car-bon monoxide (CO) selectively diffusesthrough a substantially solid barrier.


1December 2009

52 Water vapor permeates barrier:This subclass is indented under subclass 45.Process in which water (H2O) vapor selec-tively diffuses through a substantially solidbarrier.

53 Helium permeates barrier:This subclass is indented under subclass 45.Process in which helium (He) selectively dif-fuses through a substantially solid barrier.

54 Oxygen permeates barrier:This subclass is indented under subclass 45.Process in which oxygen (O2) selectively dif-fuses through a substantially solid barrier.

55 Hydrogen permeates barrier:This subclass is indented under subclass 45.Process in which hydrogen (H2) selectivelydiffuses through a substantially solid barrier.

56 Elemental metal or alloy barrier:This subclass is indented under subclass 55.Process in which hydrogen (H2) selectivelydiffuses through a substantially solid barrierthat is made of elemental metal or alloy or con-tains a layer of elemental metal or alloy.

(1) Note. The hydrogen (H2) molecule maydissociate into hydrogen (H) atoms at thesurface of the barrier. The atoms willthen diffuse through the barrier andrecombine into a hydrogen (H2) mole-cule on the downstream side of the bar-rier.

SEE OR SEARCH CLASS:210, Liquid Purification or Separation,

subclass 500.25 for a metal-contain-ing semipermeable membrane used inliquid separation.

423, Chemistry of Inorganic Compounds, subclass 658.2 for processes of pro-ducing elemental hydrogen (H) bydirect decomposition of a binary com-pound (e.g., chemical storage, etc.).

57 ELECTRIC OR ELECTROSTATICFIELD (E.G., ELECTROSTATIC PRECIP-ITATION, ETC.):This subclass is indented under the class defini-tion. Process in which an electric current isdischarged into the fluid mixture or the fluidmixture is contacted with a fluid or solid whichhas been electrified.

(1) Note. The separation of the fluid mixtureneed not be accomplished directly by theelectrical treatment, provided that theoverall process results in separation ofthe fluid mixture. The electrical treat-ment may be for the purpose of causingentrained particles to become agglomer-ated for easier removal by other means,such as filtration or deflection.

(2) Note. Gas separation processes includingthe mere application of electricity to amaterial contacting the fluid mixture forthe purpose of resistance heating is clas-sified below.

(3) Note. Processes for separating isotopesare classified based upon the specificmethods used (e.g., the separation of liq-uid isotopes by distillation is classifiedin Class 203, subclass 5; isotope separa-tion involving chemical reaction broughtabout by wave energy is found in Class204, subclasses 157.2-157.22, etc.).

SEE OR SEARCH THIS CLASS, SUB-CLASS:2 through 13, for processes involving

an electric field with control respon-sive to sensed condition.

25, for processes involving an electricfield with recording or signaling of acondition.

26, for processes involving an electricfield with timing of an operation.


classes 15 through 100 for apparatususing an electric field to separate gasconstituents. Also, see other collectedsearch class notes regarding relatedsubject matter.


December 2009

204, Chemistry: Electrical and WaveEnergy, subclasses 164 through 179 for processes involving gas treatmentby chemical reaction and electricaldischarge or chemical change by elec-trical discharge, and subclasses 554-573 and 660-674 for similar processesand apparatus for electrical separationor purification of liquids and fordegasification of liquid aided by elec-trical discharge involving the conver-sion of constituents to othercompounds. When such chemicalconversion is in doubt, placement ofelectrical processes and apparatus fordegasifying liquid is proper for Class95 or Class 96, respectively.

209, Classifying, Separating, and Assort-ing Solids, subclass 12.2 for a combi-nation process or apparatus of classi-fying, separating, and assorting solidsincluding an electrostatic field; andsubclasses 127.1-131 for process andapparatus for classifying, separating,or assorting solids by an electrostaticfield.

210, Liquid Purification or Separation, subclasses 748.01 through 748.2 forliquid purification or separation pro-cesses utilizing electrical or waveenergy directly applied to liquid ormaterial being treated.

250, Radiant Energy, subclasses 282through 284 for methods of separat-ing certain accelerated ionized mate-rial from similar accelerated ionizedmaterial having different mass-to-electric-charge ratios by use of elec-trostatic or magnetic fields.

58 With addition of solid, gas, or vapor:This subclass is indented under subclass 57.Process which includes adding a solid, gas, orvapor to the fluid mixture undergoing treat-ment or separation.

(1) Note. To come under this definition, theadded solid, gas, or vapor must not bemerely a different amount of the samefluid mixture that is to be separated, butmay be a constituent of this mixture,which may be derived from a previousseparation process.

(2) Note. The addition of solid includes theuse of a fluidized solid particle bed,regardless of whether the solid remainsentrained in the gas after passagethrough the bed. The use of a stationaryparticle bed is not considered to be addi-tion of a solid, and patents in which astationary particle bed is used will befound elsewhere under subclass 57.Also, for the purposes of this subclass,the added solid, gas, or vapor mayinclude any combination thereof (exceptfor a different amount of the fluid mix-ture to be separated, as in (1) Note),including aerosols.

SEE OR SEARCH CLASS:96, Gas Separation: Apparatus, subclass

27 for means to add charged solid orliquid particles to the gas stream, sub-class 52 for vapor or liquid contactapparatus involving electrical separa-tion, and subclass 74 for gas separa-tion apparatus including an electricalprecipitator and means to treat or con-dition the gas before, during, or afterprecipitation.

59 Electrode treating (e.g., coating, cleaning,etc.):This subclass is indented under subclass 58.Process which includes the physical treatmentof an electrode (e.g., by addition of a protectiveor reactive layer to the electrode or the removalof collected material from the electrode, etc.).

SEE OR SEARCH THIS CLASS, SUB-CLASS:74 through 76, for processes with clean-

ing of a collecting electrode but with-out the addition of a solid, gas, orvapor.


classes 28 through 51 for electricalseparation apparatus with electrodecleaner, apparatus part flusher or dis-charger, or wet collector.


1December 2009

60 Heating or cooling:This subclass is indented under subclass 58.Process in which the fluid mixture to be sepa-rated is heated or cooled either by or along withthe addition of solid, gas, or vapor.

61 Solid is electrically conducting:This subclass is indented under subclass 58.Process in which a solid of low electrical resis-tance is added to the fluid mixture.


classes 28 through 51 for electricalseparation apparatus containing elec-trodes coated with a wet conductivefilm.

62 Agglomerating gas-borne particles:This subclass is indented under subclass 58.Process in which solid or liquid particles to beseparated from a gas are agglomerated intolarger conglomerates either in the gas phase oron a collecting surface, with the agglomerationbeing facilitated by addition of a solid, gas, orvapor to the incoming fluid mixture.


77 for electrical separation apparatuscontaining electrical means foragglomerating particles.

63 And nonelectrical separation of fluid mix-ture:This subclass is indented under subclass 57.Process which includes methods of separationof the fluid mixture other than those explicitlyconnected with an electrical separation tech-nique.


the removal of material from a col-lecting electrode.


27 for electrical separation apparatuswith means to add charged liquid orsolid particles to the gaseous fluidmixture, subclass 52 for electrical

separation apparatus with means toadd a liquid or vapor to the gaseousfluid mixture, and subclass 55 forelectrical separation apparatus withserially arranged nonelectrical separa-tors.

64 Liquid addition to gaseous fluid mixture:This subclass is indented under subclass 63.Process in which a liquid is added to a gaseousfluid mixture before, during, or after electricaltreatment either (a) to cause separation or (b) tocondition the gaseous fluid mixture in any way.

SEE OR SEARCH THIS CLASS, SUB-CLASS:75, for processes involving the removal of

material from a collecting electrodeby flushing with a liquid.


classes 52 through 53 for electricalseparation apparatus with vapor orliquid contact.

65 Liquid addition precedes electrical precipi-tation:This subclass is indented under subclass 64.Process in which liquid addition is made beforethe gaseous fluid mixture is subjected to elec-trical separation.

66 With heating or cooling:This subclass is indented under subclass 65.Process including heating or cooling either as aresult of the liquid addition or as a separate,additional gas treatment.

67 By heating or cooling:This subclass is indented under subclass 63.Process in which nonelectrical gas separation iscaused by heating or cooling a gaseous fluidmixture.

68 Including cleaning or regeneration of sepa-rating means (e.g., particulate bed filter,deflector, etc.):This subclass is indented under subclass 63.Process which includes removal of collectedmaterial from or regeneration of a nonelectricalgas separating means, such as a particulate bedfilter or deflector.


December 2009

SEE OR SEARCH THIS CLASS, SUB-CLASS:90 through 148, for processes of solid

sorption which may include regenera-tion of the solid sorbent.

276, for processes of cleaning a particulatefilter bed.

278, for processes of cleaning a cohesivefilter.

SEE OR SEARCH CLASS:55, Gas Separation, subclasses 282

through 305 for gas separating appa-ratus with nonliquid cleaning meansfor separating media, and subclass431 for means contacting an apparatuspart with a fluid for discharge ofmaterial residue.

96, Gas Separation: Apparatus, subclass228 for gas separation apparatus withmeans using liquid to clean the gasseparation apparatus.

69 Distinct separation step precedes electric orelectrostatic treatment:This subclass is indented under subclass 63.Process in which at least one nonelectrical sep-arating step is performed on the fluid mixturebefore electric or electrostatic treatment.


through 337 for serial diverse sepa-rating media not including an electri-cal separation apparatus.

96, Gas Separation: Apparatus, sub-classes 55 through 59 for electricalseparation apparatus with seriallyarranged diverse separators; in partic-ular, subclass 57 for such apparatuspreceded by a nonelectrical separator.

70 Distinct separation step follows electric orelectrostatic treatment:This subclass is indented under subclass 63.Process in which at least one nonelectrical sep-arating step is performed on the fluid mixtureafter electric or electrostatic treatment.


through 337 for serial diverse sepa-rating media not including electricalseparation apparatus.

96, Gas Separation: Apparatus, sub-classes 55 through 59 for electricalseparation apparatus with seriallyarranged diverse separators.

71 With addition of liquid to gaseous fluid mix-ture:This subclass is indented under subclass 57.Process in which a liquid is added to a gaseousfluid mixture undergoing treatment, but doesnot directly result in the separation of gas con-stituents.


contacting a gaseous fluid mixturewith a liquid in a diverse type opera-tion (in which gas constituents arealso separated by nonelectrical meth-ods, such as directly results from liq-uid addition).


52 for corresponding electrical fieldseparation apparatus with means toadd liquid or vapor to the gas and sub-classes 243-371 for gas separationapparatus with gas and liquid contactmeans.

72 Vaporization of liquid:This subclass is indented under subclass 71.Process in which the added liquid is vaporizedto join the gas phase.

73 With heating or cooling:This subclass is indented under subclass 57.Process which includes heating or cooling ofthe fluid mixture being treated.

SEE OR SEARCH THIS CLASS, SUB-CLASS:67, for related processes in which a non-

electrical gas separation is caused byheat exchange with the gas.


1December 2009

74 With cleaning of collector electrode:This subclass is indented under subclass 57.Process which includes cleaning or removingof a deposited constituent from an electricalelement provided to attract and retain the con-stituent.


classes 28 through 51 for correspond-ing electrode cleaning means.

134, Cleaning and Liquid Contact WithSolids, appropriate subclasses forcleaning matter from solid materialsor objects.

75 By liquid flushing:This subclass is indented under subclass 74.Process in which the cleaning of the element isperformed by the application of a liquidstream.


classes 43 through 50 for correspond-ing apparatus with fluid contactingmeans.

76 By scraping or vibrating:This subclass is indented under subclass 74.Process in which the cleaning of the element isperformed by the application of mechanicalcontacting or jarring means to remove retainedmaterial.


classes 32 through 38 for correspond-ing apparatus with vibrating means,and subclass 51 for correspondingapparatus with scraping means.

77 Continuously moving electrode:This subclass is indented under subclass 57.Process in which an element discharging elec-tricity into the fluid mixture or collectingdeposits therefrom continually moves duringoperation.


classes 39 through 42 for electricalseparation apparatus with movably

mounted electrode assembly forcleaning purposes and subclass 94 forelectrode supporting means permit-ting movement thereof during use orfor orientation.

78 Including baffling, deflection, or restrictionof gas flow:This subclass is indented under subclass 57.Process in which a restriction or redirection ofgas flow is caused by inclusion of a baffle,deflector, or specially shaped electrode for thepurpose of such restriction.


classes 60 through 73 for correspond-ing apparatus with gas flow distribu-tion means, subclasses 95-97 forapparatus with specific type or shapeof discharge electrode, and subclasses98-100 for specific collector means.

79 Plural separate stages or zones (e.g., sepa-rate ionization and collection regions, etc.):This subclass is indented under subclass 57.Process in which a gaseous fluid mixturepasses through two or more distinct regions orunits, such regions providing either multipleidentical gas treatments or plural diverse treat-ments for removal of entrained particles.

(1) Note. The stages or zones may bearranged in series or in parallel.

(2) Note. A single stage with two or moreregions or zones of differing appliedvoltage is included under this definition.

SEE OR SEARCH THIS CLASS, SUB-CLASS:63 through 70, for processes with non-

electrical gas separating steps.


classes 55 through 59 for electricalseparation apparatus with serialdiverse separators and subclasses 75-79 for electrical separation apparatuswith diverse or serially distinct elec-trical fields.


December 2009

80 Pulsing or time-varying electric field (e.g.,AC, pulsed DC, etc.):This subclass is indented under subclass 79.Process involving the application of a voltagewhich fluctuates with time during treatment ofthe gaseous fluid mixture.


54 for electrical separation apparatushaving an alternating current field.

81 Pulsing or time-varying electric field (e.g.,AC, pulsed DC, etc.):This subclass is indented under subclass 57.Process involving the application of a voltagewhich fluctuates with time during treatment ofthe gaseous fluid mixture.


54 for electrical separation apparatushaving an alternating current field.

82 CHROMATOGRAPHY:This subclass is indented under the class defini-tion. Process in which (a) the plurality of gasesto be separated enters a column to contact a liq-uid, known as the “stationary liquid phase,”supported by a base of solid material to succes-sively sorb therein the different gases of themixture or (b) the plurality of gases to be sepa-rated enters a column to contact a solid sorbentto successively sorb thereon the different gasesof the mixture with or without subsequentlysuccessively eluting or displacing the sorbedgases in (a) or (b) with a gas which is inert withrespect to the sorbed gases and sorbent; andsubcombinations of the processes in (a) and (b)that do not result in separation when the sub-combinations are not provided for elsewhere.

(1) Note. The plurality of gases is usuallyallowed to flow slowly through a columnof particulate sorbent. Different gaseswill pass at different speeds through thecolumn and will eventually be separatedinto zones. The zones can be eluted bypassing an inert gas through the columnand collecting the various fractions.

(2) Note. When a liquid is supported by abase of solid material for the separation

of the mixture of gases, the process isknown as “gas-liquid chromatography”or “GLC.” If liquid is not present, theprocess is known as “gas-solid chroma-tography.” Other phrases used whenreferring to chromatography are “gas-chromatography” or “GC,” “vapor-phasechromatography” or “VPC,” “gas-liquidpartition chromatography,” “vapor frac-tometry,” “capillary column gas chroma-tography” or “CC-GC,” and “partitionchromatography.”

(3) Note. Sometimes a “carrier” gas ismixed with or used to propel the plural-ity of gases to be separated through thechromatography column.

(4) Note. The plurality of gases to be sepa-rated may be obtained by vaporizing aliquid. The liquid that is injected into thechromatography column is vaporized,and then the resulting vapors are sepa-rated in the chromatography column.

SEE OR SEARCH THIS CLASS, SUB-CLASS:245 through 246, and 263-265, for pro-

cesses of separating gases from liq-uids by contacting the liquid with agas.


19.02, 23.22-23.27, and 23.35-23.42for chromatography including analy-sis of eluted or displaced gas.

96, Gas Separation: Apparatus, sub-classes 101 through 107 for gas chro-matography apparatus.

210, Liquid Purification or Separation, subclasses 656 through 694 and198.2-198.3 for processes and appara-tus of liquid purification or separationinvolving chromatography.

436, Chemistry: Analytical and Immuno-logical Testing, subclasses 161through 162 for processes whichinvolve a chemical reaction for ana-lytical testing including chromatogra-phy and for processes of analysis ofthe chemical properties of a sampleincluding chromatography.


1December 2009

83 Liquid supported on surface of capillary col-umn:This subclass is indented under subclass 82.Process in which the base of solid material sup-porting the stationary liquid phase as a thinfilm is the inner surface of a capillary tube orcolumn.

84 Liquid supported on particulate packing:This subclass is indented under subclass 82.Process in which the base of solid material sup-porting the stationary liquid phase is a granularsolid.

85 Including use of gas flow distributor in col-umn:This subclass is indented under subclass 82.Process in which gas is directed or channelledby use of a deflector inside the column.


107 for corresponding apparatus. Pat-ents are not cross-referenced fromClass 96, subclass 107 to this subclassbased only on disclosure. Therefore,relevant disclosures to gas separationprocesses may be found in the appara-tus area.

86 Plural separate columns:This subclass is indented under subclass 82.Process in which the plurality of gases passesthrough two or more parallel or serial columns.


104 for chromatographic apparatushaving two or more separate and dis-tinct stages or zones.

87 With heating or cooling:This subclass is indented under subclass 82.Process in which the plurality of gases, a liq-uid, a separated constituent, or an apparatusinvolved in the process is heated or cooled(e.g., the column may be heated in order todegas the solid sorbent or a gas may be heatedor cooled, etc.).

88 Specific column packing or sorbent material(e.g., particle size, composition, etc.):This subclass is indented under subclass 82.Process in which a specified packing or sorbentmaterial (e.g., sorbent compositions, particlesize, etc.) is used.

89 Injection, per se, without separation:This subclass is indented under subclass 82.Process in which a method of injecting the plu-rality of gases or a liquid into the chromatogra-phy column is claimed, per se, without gasseparation.

SEE OR SEARCH CLASS:141, Fluent Material Handling, With

Receiver or Receiver CoactingMeans, appropriate subclasses forprocesses and apparatus for the trans-fer of fluent material through a flowconfining system, the source andreceiver parts of which are normallyseparable.

90 SOLID SORPTION:This subclass is indented under the class defini-tion. Process in which a solid sorbent is usedto retain on its internal or external surfaces aconstituent of the fluid mixture passing in con-tact therewith.

(1) Note. A solid sorbent is a solid materialwhich separates a constituent (e.g., a gas,vapor, etc.) from a fluid mixture contain-ing such constituents in a “quasi-chemi-cal” manner. The action in mostinstances is that of selective retention(i.e., the sorbent removes only the part ofthe fluid mixture for which it has thegreatest affinity). The retained constitu-ent cannot be removed by shaking,brushing, or similar mechanical action,but generally can be removed by heating,pressure reduction, or use of a strippingor denuding fluid. A filter (particulatesolids or other) has no particular “chemi-cal” affinity for a constituent of a fluidmixture. The separation in the case of afilter depends on a mechanical entrap-ment of solid or liquid particles becauseof their relatively large size comparedwith the interstices or spaces betweenindividual elements of the filter. The


December 2009

retained particles can be removed bybrushing, wiping, shaking, or similarmechanical action.

(2) Note. “Absorption” is the holding of aconstituent by cohesion or capillaryaction in the pores of a solid. “Adsorp-tion” is the ability of a sorbent to hold orconcentrate gases, liquids, or dissolvedsubstances upon its surface.

(3) Note. The desorption of a solid sorbent,which may appear in one of the sub-classes below, must be before or after itsuse as a sorbent, as claimed. The meretreatment of a solid sorbent to drive offthe fluid sorbed thereon or therein isproper subject matter for Class 502. Seesearch class note below.

(4) Note. This subclass and the subclassesindented hereunder will take the degas-ification of a liquid by use of a solid sor-bent.

SEE OR SEARCH THIS CLASS, SUB-CLASS:41, for processes using compressing and

cooling of a fluid mixture to separatea constituent from the mixture in addi-tion to using a solid sorbent to sepa-rate a constituent from the gas.


classes 108 through 154 for appara-tus containing solid sorbents.

203, Distillation: Processes, Separatory, subclass 41 for a separatory distilla-tion process including the step ofpassing the produced vapor through asolid sorbent.

210, Liquid Purification or Separation, subclasses 660 through 694 for pro-cesses of using a solid sorbent topurify or separate a liquid.

420, Alloys or Metallic Compositions, subclass 900 for hydrogen (H2) stor-age alloys or metallic compositions.

423, Chemistry of Inorganic Compounds, subclass 658.2 for processes of pro-ducing elemental hydrogen (H) bydirect decomposition of a binary com-pound (e.g., chemical storage, etc.).

436, Chemistry: Analytical and Immuno-logical Testing, subclass 167 for pro-cesses wherein the basis for analysisis an optical result of a chemical reac-tion that is measured mechanically orvisually, including solid sorption of agas.

502, Catalyst, Solid Sorbent, or SupportTherefor: Product or Process of Mak-ing, subclasses 20 through 56 forregenerating or rehabilitating solidsorbent compositions, per se, sub-classes 60-87 for zeolite compositionsand for processes of making zeolitecompositions, and subclasses 400-438for other solid sorbent compositionsand for processes of making solid sor-bent compositions. Class 95 will takethe combination of gas separationusing a solid sorbent composition andregenerating or rehabilitating the solidsorbent composition.

585, Chemistry of Hydrocarbon Com-pounds, subclasses 820 through 831 for processes in which a mixture of ahydrocarbon compound with anothersubstance is treated to recover thatsame compound in a more usable con-dition, that is, a purer or more desir-able condition, by a treatment whichcomprises separating the hydrocar-bon from the other substance by con-tact with a solid sorbent.

91 Soluble or deliquescent material used:This subclass is indented under subclass 90.Process in which the solid sorbent dissolves inthe constituent retained or sorbed therein orthereon.

(1) Note. The resultant solution may be usedin a liquid contacting zone to aid in theseparation.

(2) Note. A deliquescent material is a water-soluble chemical salt used to sorb atmo-spheric water vapor.


classes 118 through 120 for apparatuscontaining a soluble or deliquescentsorbent material.


1December 2009

92 And liquid contact (e.g., scrubbing, sorp-tion, etc.):This subclass is indented under subclass 90.Process in which a gaseous fluid mixture iscontacted by a liquid in addition to a solid sor-bent in order to remove a gas, solid, or liquidtherefrom.

SEE OR SEARCH THIS CLASS, SUB-CLASS:36 through 38, for processes in which a

liquid-solid slurry is used to cause gasseparation.

93 Sweep gas used on solid sorbent:This subclass is indented under subclass 92.Process in which a gas is used to purge the con-stituent separated from the solid sorbent or agas is used to regenerate the solid sorbent.

SEE OR SEARCH THIS CLASS, SUB-CLASS:97 through 102, and 104-105, for pro-

cesses of using a sweep gas on a solidsorbent including reduction of pres-sure.

94 And recycle or reuse of contact liquid forfurther contact:This subclass is indented under subclass 92.Process in which (a) the contact liquid is recir-culated for further contact with the fluid mix-ture or a portion thereof or (b) the contactliquid is used in another step of the process forfurther contact with the fluid mixture or a por-tion thereof.

95 Including reduction of pressure:This subclass is indented under subclass 90.Process in which pressure over a mass of solidsorbent is decreased in order to separate fromthe solid sorbent the constituent sorbed in thegas separation process.

96 Plural pressure varying steps (e.g., pressureswing adsorption, etc.):This subclass is indented under subclass 95.Process in which there is more than one step ofincreasing or decreasing the pressure on thesolid sorbent.

97 Sweep gas used:This subclass is indented under subclass 96.Process in which a gas is used to purge the con-stituent separated from the solid sorbent or agas is used to regenerate the solid sorbent.

SEE OR SEARCH THIS CLASS, SUB-CLASS:93, for processes of solid sorption and liq-

uid contact including use of a sweepgas on a solid sorbent.

104 through 105, for processes in which asweep gas is used to carry desorbedgas without the use of plural pressurevarying.

98 Feed gas or constituent thereof is sweep gas:This subclass is indented under subclass 97.Process in which the sweep gas is the gaseousfluid mixture or a portion thereof, before orafter being treated or separated.

99 With heating or cooling:This subclass is indented under subclass 98.Process in which the solid sorbent or a gas isheated or cooled.

100 Stepped pressure reduction:This subclass is indented under subclass 98.Process in which the pressure over the solidsorbent is decreased in more than one step.

SEE OR SEARCH THIS CLASS, SUB-CLASS:103, for processes in which there is use of

pressure reduction in more than onestep without the use of a sweep gas tocarry desorbed gas.

101 Vacuum applied:This subclass is indented under subclass 100.Process in which a step of pressure reduction isaccomplished by using a pressure below that ofthe atmosphere.

102 Vacuum applied:This subclass is indented under subclass 98.Process in which a step of pressure reduction isaccomplished by using a pressure below that ofthe atmosphere.


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103 Stepped pressure reduction:This subclass is indented under subclass 96.Process in which the pressure over the solidsorbent is decreased in more than one step.

SEE OR SEARCH THIS CLASS, SUB-CLASS:100, for processes in which there is use of

pressure reduction in more than onestep with the use of a sweep gas tocarry desorbed gas.

104 Sweep gas used:This subclass is indented under subclass 95.Process in which a gas is used to purge the con-stituent separated from the sorbent or a gas isused to regenerate the solid sorbent.

SEE OR SEARCH THIS CLASS, SUB-CLASS:93, for processes of solid sorption and liq-

uid contact including use of a sweepgas on a solid sorbent.

97 through 102, for processes in which asweep gas is used to carry desorbedgas with the use of plural pressurevarying.

105 Feed gas or constituent thereof is sweep gas:This subclass is indented under subclass 104.Process in which the sweep gas is the gaseousfluid mixture or a portion thereof, before orafter being treated or separated.

106 With heating or cooling:This subclass is indented under subclass 95.Process in which the solid sorbent or a gas isheated or cooled.

107 Moving sorbent:This subclass is indented under subclass 90.Process in which the solid sorbent is movedfrom one zone to another by moving a housing,is moved from one zone to another in a station-ary housing, or is blown about or fluidized by agas in a housing.

(1) Note. The zones need not all be for sorb-ing the gas or for desorbing the solid sor-bent; it is sufficient that the solid sorbentbe moved from one zone to another, ineach of which zones the solid sorbenteither is treated or is used to treat.


150 for apparatus having a movingsolid sorbent.

108 Fluidized bed:This subclass is indented under subclass 107.Process in which the solid sorbent is blownabout or fluidized by a gas in a housing.

109 Having gravity flow of sorbent from zone tozone:This subclass is indented under subclass 108.Process in which the solid sorbent is movedfrom one zone to another in a stationary hous-ing by the forces of gravity.

110 Gravity flow of sorbent from zone to zone:This subclass is indented under subclass 107.Process in which the solid sorbent is movedfrom one zone to another in a stationary hous-ing by the forces of gravity.

111 Sweep gas used:This subclass is indented under subclass 110.Process in which a gas is used to purge a con-stituent separated from the solid sorbent or agas is used to regenerate the solid sorbent.

112 Steam is sweep gas:This subclass is indented under subclass 111.Process in which the sweep gas is steam.

113 Rotating housing containing fixed sorbentor rotating plurality of housings:This subclass is indented under subclass 107.Process in which the housing containing afixed solid sorbent turns on its axis in order tomove the solid sorbent from one treatmentzone to another or a plurality of housings isturned about a central axis to the housings toplace a housing in a position of use or nonuseor regeneration.

114 With plural indirect heat transfer steps onsolid sorbent or gaseous fluid mixture orconstituent thereof:This subclass is indented under subclass 90.Process in which there is more than one step ofheating or cooling the solid sorbent or the gas-eous fluid mixture or constituent thereofthrough a wall before or after separation.


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(1) Note. The heat transfer steps must bepart of a larger process containing sub-ject matter for Class 95, such as will befound in this and the indented subclasswhere the heat transfer steps are com-bined with sorption of a constituent froma gas on a solid sorbent. If the only sepa-ration involved is conducted by the heattransfer steps, then classification in Class165 is proper.

SEE OR SEARCH CLASS:165, Heat Exchange, appropriate sub-

classes for processes where only indi-rect heat exchange causes theseparation of a constituent from a gas.

115 Heating and cooling:This subclass is indented under subclass 114.Process in which there is heating and coolingof the solid sorbent or of a gas.

SEE OR SEARCH CLASS:165, Heat Exchange, subclasses 58

through 66 and 201-265 for processesof heating and cooling where only theindirect heat exchange causes the sep-aration of a constituent from a gas.

116 Inorganic gas or liquid particle sorbed (e.g.,vapor, mist, etc.):This subclass is indented under subclass 90.Process in which an inorganic gas or liquid par-ticle (e.g., vapor, mist, etc.) is sorbed from theplurality of gases or the gas with entrained liq-uid particles.

(1) Note. For purposes of classification inthis area, “inorganic” compounds or ele-ments are those that would fall withinthe definition of Class 423. For example,the cyanides (CN joined only to a metalor to hydrogen) and the carbon oxidesare found in the indented subclasses.

117 Water sorbed:This subclass is indented under subclass 116.Process in which water is sorbed from the plu-rality of gases or the gas with entrained liquidparticles.

SEE OR SEARCH THIS CLASS, SUB-CLASS:91, for processes in which water-soluble

chemical salts are used to sorb atmo-spheric water vapor.

118 Plural separating treatments of gas by solidsorbent to remove water:This subclass is indented under subclass 117.Process in which the gas is passed through aplurality of discrete or diverse separatingstages or steps, with the solid sorbent being thesame or a different solid sorbent in each step ofthe process.

119 And regeneration of any solid sorbent:This subclass is indented under subclass 118.Process in which at least one of the solid sor-bents is revivified or regenerated.

120 Heating or cooling:This subclass is indented under subclass 119.Process in which the solid sorbent or a gas isheated or cooled.

121 And regeneration of solid sorbent:This subclass is indented under subclass 117.Process in which the solid sorbent is revivifiedor regenerated.

122 Sweep gas used:This subclass is indented under subclass 121.Process in which a gas is used to purge thewater separated from the solid sorbent or a gasis used to regenerate the solid sorbent.

123 Hot sweep gas:This subclass is indented under subclass 122.Process in which there is a positive step of rais-ing the temperature of the sweep gas above theambient temperature or the sweep gas isalready at a temperature above the ambienttemperature.

124 And cooling of sweep gas:This subclass is indented under subclass 123.Process in which the sweep gas is cooled.

125 And cooling of solid sorbent:This subclass is indented under subclass 123.Process in which the solid sorbent is cooled.


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126 By heating:This subclass is indented under subclass 121.Process in which the solid sorbent is revivifiedor regenerated by heating.

127 Noble gas sorbed:This subclass is indented under subclass 116.Process in which a noble gas (i.e., helium (He),neon (Ne), argon (Ar), krypton (Kr), xenon(Xe), or radon (Rn)) is sorbed.

128 Nitrogen containing compound sorbed:This subclass is indented under subclass 116.Process in which a nitrogen containing com-pound is sorbed.

129 Nitrogen oxide sorbed:This subclass is indented under subclass 128.Process in which a nitrogen oxide (e.g., nitricoxide (NO), nitrogen dioxide (NO2), etc.) issorbed.

130 Nitrogen sorbed:This subclass is indented under subclass 116.Process in which nitrogen (N2) is sorbed.

131 Halogen or halogen containing compoundsorbed:This subclass is indented under subclass 116.Process in which a halogen (i.e., fluorine (F),chlorine (Cl), bromine (Br), iodine (I), astatine(At)) or a halogen containing compound issorbed.

132 Chlorine or chlorine containing compoundsorbed:This subclass is indented under subclass 131.Process in which chlorine (Cl) or a chlorinecontaining compound is sorbed.

133 Metal or metal containing compoundsorbed:This subclass is indented under subclass 116.Process in which a metal or metal containingcompound is sorbed.

(1) Note. Arsenic (As) is considered to be ametal.

134 Mercury sorbed:This subclass is indented under subclass 133.Process in which mercury (Hg) is sorbed.

135 Sulfur containing compound sorbed:This subclass is indented under subclass 116.Process in which a sulfur (S) containing com-pound is sorbed.

136 Hydrogen sulfide sorbed:This subclass is indented under subclass 135.Process in which hydrogen sulfide (H2S) issorbed.

137 Sulfur dioxide or sulfur trioxide sorbed:This subclass is indented under subclass 135.Process in which sulfur dioxide (SO2) or sulfurtrioxide (SO3) is sorbed.

138 Oxygen or ozone sorbed:This subclass is indented under subclass 116.Process in which oxygen (O2) or ozone (O3) issorbed.

139 Carbon dioxide sorbed:This subclass is indented under subclass 116.Process in which carbon dioxide (CO2) issorbed.

140 Carbon monoxide sorbed:This subclass is indented under subclass 116.Process in which carbon monoxide (CO) issorbed.

141 Organic gas or liquid particle sorbed (e.g.,vapor, mist, etc.):This subclass is indented under subclass 90.Process in which an organic gas or liquid parti-cle (e.g., vapor, mist, etc.) is sorbed from theplurality of gases or the gas with entrained liq-uid particles.

(1) Note. For purposes of classification inthis area, “organic” compounds are thosethat would fall within the definitions ofClass 260.

142 Halogen containing compound sorbed (e.g.,phosgene, etc.):This subclass is indented under subclass 141.Process in which a halogen containing (i.e.,fluorine (F), chlorine (Cl), bromine (Br), iodine(I), astatine (At)) compound (e.g., phosgene,etc.) is sorbed.


1December 2009

143 Hydrocarbon sorbed:This subclass is indented under subclass 141.Process in which a hydrocarbon is sorbed.

144 Alkene sorbed:This subclass is indented under subclass 143.Process in which an alkene (i.e., olefin) issorbed.

145 Alkyne sorbed (e.g., acetylene, etc.):This subclass is indented under subclass 143.Process in which an alkyne (i.e., alkine) issorbed (e.g., acetylene, etc.).

146 Gasoline sorbed:This subclass is indented under subclass 143.Process in which gasoline is sorbed.

147 Benzene ring containing compound sorbed:This subclass is indented under subclass 143.Process in which a benzene ring containingcompound is sorbed.

148 And regeneration:This subclass is indented under subclass 90.Process in which the solid sorbent is revivifiedor regenerated.

SEE OR SEARCH THIS CLASS, SUB-CLASS:95 through 106, for processes of regener-

ation of the solid sorbent including thereduction of pressure.

107 through 113, for processes of regener-ation of the solid sorbent including theuse of a moving sorbent.

114 through 115, for processes of regener-ation of the solid sorbent includingplural indirect heat transfer steps.

116 through 140, and 141-147, for pro-cesses of regeneration of the solid sor-bent including the sorption of aspecifically named compound.

149 LIQUID CONTACTING (E.G., SORP-TION, SCRUBBING, ETC.):This subclass is indented under the class defini-tion. Process in which the fluid mixture is con-tacted with a liquid.

(1) Note. The contact of the fluid mixturewith a liquid generally results in separa-tion of a gas, solid particles, or liquid

particles from a gaseous fluid mixture(e.g., sorption, scrubbing, etc.). The con-tact of the fluid mixture with a liquiddoes not have to cause separation of themixture, however, but may be used forother reasons (e.g., to humidify a gas,etc.). As long as there is separation of thefluid mixture by some process of thisclass along with the contacting of themixture with a liquid for reasons otherthan separation, the patent will be placedhere (e.g., filtration plus humidification,etc.).

SEE OR SEARCH THIS CLASS, SUB-CLASS:44, for selective diffusion of gases

through an immobilized liquid.64 through 66, and 71-72, for electric or

electrostatic field processes com-bined with liquid addition to the gas.


classes 243 through 371 for gas sepa-ration apparatus using gas and liquidcontact means combined with meansto further handle the process constitu-ents before, during, or after separa-tion. See the class line to Class 261 inSection III, References to OtherClasses, of this class for furtherdetails about gas and liquid contactapparatus and processes.

261, Gas and Liquid Contact Apparatus,appropriate subclasses for gas and liq-uid contact apparatus, per se, with orwithout separation, and for gas andliquid contact processes, per se, with-out separation (e.g., humidification,etc.). See the class line to Class 261 inSection III, References to OtherClasses of this class for further detailsabout gas and liquid contact apparatusand processes.

436, Chemistry: Analytical and Immuno-logical Testing, subclass 168 for pro-cesses wherein the basis for analysisis an optical result of a chemical reac-tion that is measured mechanically orvisually, including liquid sorption of agas.


December 2009

585, Chemistry of Hydrocarbon Com-pounds, subclasses 833 through 868for processes in which a mixture of ahydrocarbon compound with anothersubstance is treated to recover thatsame compound in a more usable con-dition, that is, a purer or more desir-able condition, by a treatment whichcomprises separating the hydrocar-bon from the other substance by addi-tion of an extraneous agent (e.g.,solvent, etc.).

150 Including foaming of liquid to aid in the sep-aration:This subclass is indented under subclass 149.Process in which a frothy or sudslike disper-sion of gas in the contact liquid is formed to aidin the separation.

(1) Note. When foam is intentionallyformed, it will be assumed to aid in theseparation unless otherwise stated.

SEE OR SEARCH CLASS:516, Colloid Systems and Wetting Agents;

Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, appropriate subclasses forcolloid systems or agents for such sys-tems or making or stabilizing suchsystems or agents (subclasses 10-19for foaming), appropriate subclassesfor processes of or compositions foror subcombination compositions forthe breaking of or inhibiting of colloidsystems (subclasses 115-134 fordefoaming); in each instance, whengenerically claimed or when there isno hierarchically superior provision inthe USPC for the specifically claimedart.

151 Mechanical agitation of liquid body to con-tact gaseous fluid mixture:This subclass is indented under subclass 149.Process in which the gaseous fluid mixture iscontacted with the liquid by mechanically stir-ring a liquid body or mass or by mechanicallydisturbing the surface of a liquid body or massin such a way that the liquid is flung into themixture.

SEE OR SEARCH THIS CLASS, SUB-CLASS:150, for processes in which agitation of the

liquid body causes foaming of the liq-uid.

185, for processes of contacting a fluidmixture with a liquid combined withmechanical agitating in order todegasify the liquid.

260, for processes of degasification of aliquid by agitating.

152 Coagulating or flocculating agent:This subclass is indented under subclass 149.Process in which solid particles are removedfrom a gas by a contact liquid that contains anagent that causes the solid particles to agglom-erate.

(1) Note. These agents are known as “coag-ulating” agents, “flocculating” agents, or“flocculent” materials.


Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 98 through 112 for colloid systems of continuous orsemicontinuous solid phase with dis-continuous liquid phase (gels, pastes,flocs, coagulates) or agents for suchsystems or making or stabilizing suchsystems or agents, when genericallyclaimed or when there is no hierarchi-cally superior provision in the USPCfor the specifically claimed art.

153 Hydrate inhibitor:This subclass is indented under subclass 149.Process in which the contact liquid contains anagent that prevents formation of a substancecontaining water combined in the molecularform (e.g., agent prevents formation of meth-ane hydrate: CH4-7H2O, ethane hydrate:C2H6-8H2O, chlorine hydrate: Cl2-8H2O, etc.).

154 Surfactant or wetting agent:This subclass is indented under subclass 149.Process in which the contact liquid contains anagent that reduces the surface tension of thecontact liquid.


1December 2009

(1) Note. These agents are known as “sur-factants,” “wetting” agents, or “surface-active” substances.

155 Defoaming or antifoaming agent:This subclass is indented under subclass 149.Process in which the contact liquid contains anagent that either (a) resolves or breaks a frothyor sudslike dispersion that was formed duringthe liquid-gas contact into separate fluid phasesor (b) prevents formation of a frothy or suds-like dispersion during the liquid-gas contact.

SEE OR SEARCH THIS CLASS, SUB-CLASS:157, and 242, for other processes of

defoaming a liquid.


Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 115 through134 for processes of or compositionsfor or subcombination compositionsfor the breaking of or inhibiting offoam colloid systems, when generi-cally claimed or when there is no hier-archically superior provision in theUSPC for the specifically claimed art.

156 And degasification of a liquid:This subclass is indented under subclass 149.Process in which a gas is removed from a liq-uid.

(1) Note. Generally, the patents in this sub-class and the subclasses indented here-under involve contacting a plurality ofgases, with or without solid or liquid par-ticles entrained therein, with a liquid inorder to sorb or remove a gas or gasesfrom the plurality of gases, allowing theremaining gas or gases to pass out ofcontact with the liquid. The liquid withgas entrained therein then is treated toremove the sorbed gas. The removal maybe for regenerating the liquid for furtheruse or may be for obtaining the sorbedgas. In addition, this area takes processesin which the degasification of a liquidoccurs first and the removed gas is sub-

jected to a liquid contacting step (seesubclass 158).

(2) Note. In order for a patent to be placedhere, the gas sorbed by a liquid from aplurality of gases and removed from theliquid must be normally gaseous at atemperature of 0°C and a pressure of 760mm Hg (e.g., hydrogen sulfide (H2S),carbon monoxide (CO), carbon dioxide(CO2), ethane (C2H6), ammonia (NH3),etc.). If, however, a constituent is at atemperature above its boiling tempera-ture for a particular pressure, then theconstituent is presumed to be a gas andthe patent is placed here when the con-stituent is sorbed as a gas by a liquid,remains in gaseous phase in the liquid,and is removed from the liquid as a gas.The C4 hydrocarbons, which have boil-ing points above and below a tempera-ture of 0°C, are classified according totheir individual boiling points in sub-classes 149-240 (e.g., butane with a boil-ing point of -0.5°C at 760 mm Hgpressure is a gas at a temperature of 0°Cand 760 mm Hg pressure; whereas 1,2-butadiene with a boiling point of 10.8°Cat 760 mm Hg pressure is a liquid at atemperature of 0°C and 760 mm Hgpressure). This handling of the C4 hydro-carbons is in contrast to that of Class203, in which all of the C4 hydrocarbonsare arbitrarily classified as liquids at atemperature of 0°C and 760 mm Hgpressure.


liquid by use of sound waves.46, for processes of degasification of a


188 through 194, and 206-209, forremoval of a liquid from the contactliquid.

241 through 266, for processes of degas-ification of a liquid without liquidcontacting.


December 2009


classes 155 through 220 for degasify-ing means for liquid.

157 Defoaming:This subclass is indented under subclass 156.Process in which a frothy or sudslike disper-sion that was formed during the liquid-gas con-tact or was present before the liquid-gascontact is resolved or broken into separate fluidphases.


defoaming a liquid.


classes 176 through 180 for defoam-ing apparatus.

516, Colloid Systems and Wetting Agents;Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 115 through134 for processes of or compositionsfor or subcombination compositionsfor the breaking of or inhibiting offoam colloid systems, when generi-cally claimed or when there is no hier-archically superior provision in theUSPC for the specifically claimed art.

158 Degasification step occurs first, withremoved gas subsequently contacted by liq-uid:This subclass is indented under subclass 156.Process in which a liquid with gas entrainedtherein is degassed and the removed gas is thencontacted with a liquid.

159 By stripping with gas:This subclass is indented under subclass 156.Process in which the gas is removed from thecontact liquid by passing a gas through or incontact with the contact liquid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:83, and 84, for processes of eluting or dis-

placing separated constituents from a

chromatographic column comprisinga liquid solvent on a solid base.

191, and 207, for separation of liquid fromcontact liquid by stripping with gas.

245 through 246, for plural successive liq-uid degassing treatments whichinclude stripping with gas.

263 through 265, for degasification of liq-uid by stripping with gas.


classes 202 through 203 for degasify-ing means for liquid with gas contact-ing means.

160 And reduction of pressure (e.g., flashing,etc.):This subclass is indented under subclass 159.Process in which the pressure acting on thecontact liquid is decreased.

(1) Note. The pressure reduction may beused in a separate step in order toremove gas from the contact liquid inaddition to the step of removing gasfrom the contact liquid by stripping withgas, or the pressure reduction may beused in order to aid the removal by strip-ping with gas.

SEE OR SEARCH THIS CLASS, SUB-CLASS:172 through 177, for liquid contacting and

degasification of liquid by reductionof pressure.

247 through 250, for plural successive liq-uid degassing treatments whichinclude reduction of pressure.

266, for degasification of liquid by reduc-tion of pressure.


classes 193 through 201 for degasify-ing means for liquid of the pressurereducing type.

161 And heating:This subclass is indented under subclass 160.Process in which the contact liquid or a gas isheated.


1December 2009

(1) Note. The heating may be used in a sepa-rate step in order to remove gas from thecontact liquid in addition to another stepof removing gas from the contact liquid,or the heating may be used in order toaid the removal by stripping with gas orby reduction of pressure.


degasification of liquid by strippingwith gas combined with heating.

173 through 174, for liquid contacting anddegasification of liquid by reductionof pressure combined with heating.

178 through 184, for liquid contacting anddegasification of liquid by heating.

251 through 252, for plural successive liq-uid degassing treatments whichinclude heating.


218 for heat exchange apparatus todegasify liquid.

162 Steam is stripping gas:This subclass is indented under subclass 161.Process in which the stripping gas is steam.

163 Liquid recycled or reused:This subclass is indented under subclass 160.Process in which (a) the contact liquid is recir-culated for further contact with the fluid mix-ture or a portion thereof or (b) the contactliquid is used in another step of the process.

164 Feed gas or constituent thereof is strippinggas:This subclass is indented under subclass 160.Process in which the stripping gas is the gas-eous fluid mixture or a portion thereof, beforeor after being treated or separated.


(1) Note. The heating may be used in a sepa-rate step in order to remove gas from theliquid in addition to the step of removing

gas from the liquid by stripping with gas,or the heating may be used in order toaid the removal by stripping with gas.


degasification of liquid by strippingwith gas combined with reduction ofpressure and heating.







167 Vaporized component of contact liquid isstripping gas:This subclass is indented under subclass 165.Process in which a constituent of the contactliquid is gasified and this constituent removesanother gas from the contact liquid.



170 Air is stripping gas:This subclass is indented under subclass 159.Process in which the stripping gas is air.


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171 Inert stripping gas:This subclass is indented under subclass 159.Process in which the stripping gas is specifiedas being inert or is one of the following gases:helium (He), neon (Ne), argon (Ar), krypton(Kr), xenon (Xe), radon (Rn), nitrogen (N2), orcarbon dioxide (CO2).

172 By reduction of pressure (e.g., flashing, etc.):This subclass is indented under subclass 156.Process in which the gas is removed from thecontact liquid by decreasing the pressure actingon the contact liquid.


contacting and degasification of liquidby stripping with gas in which there isreduction of pressure.

192, and 208, for separation of liquid fromcontact liquid by reduction of pres-sure.






(1) Note. The heating may be used in a sepa-rate step in order to remove gas from theliquid in addition to the step of removinggas from the liquid by reduction of pres-sure, or the heating may be used in orderto aid the removal by reduction of pres-sure.


degasification of liquid by stripping

with gas combined with reduction ofpressure and heating.

165 through 168, for liquid contacting anddegasification of liquid by strippingwith gas combined with heating.






175 Vacuum applied:This subclass is indented under subclass 172.Process in which the step of pressure reductionis accomplished by using a pressure below thatof the atmosphere.

176 Removed gas recycled:This subclass is indented under subclass 172.Process in which the gas removed from thecontact liquid is recirculated to the fluid mix-ture for further contact with liquid.


178 By heating:This subclass is indented under subclass 156.Process in which the gas is removed from thecontact liquid by heating.


degasification of liquid by strippingwith gas combined with reduction ofpressure and heating.


1December 2009

165 through 168, for liquid contacting anddegasification of liquid by strippingwith gas combined with heating.


193, and 209, for separation of liquid fromcontact liquid by heating.





180 Liquid cooling step before being recycled:This subclass is indented under subclass 179.Process in which there is a step of lowering thetemperature of the liquid before it is recycled.

181 Sulfur compound removed:This subclass is indented under subclass 178.Process in which a gaseous sulfur (S) com-pound is sorbed by the contact liquid and thenis removed from the contact liquid by heating.

182 Halogen compound removed:This subclass is indented under subclass 178.Process in which a gaseous halogen compound(i.e., a compound with fluorine (F), chlorine(Cl), bromine (Br), iodine (I), astatine (At)) issorbed by the contact liquid and then isremoved from the contact liquid by heating.

183 Carbon dioxide removed:This subclass is indented under subclass 178.Process in which carbon dioxide (CO2) issorbed by the contact liquid and then isremoved from the contact liquid by heating.

184 Organic compound removed:This subclass is indented under subclass 178.Process in which a gaseous organic compoundis sorbed by the contact liquid and then isremoved from the contact liquid by heating.

185 By liquid flow modifying or mechanical agi-tating:This subclass is indented under subclass 156.Process in which the gas is removed from thecontact liquid by mixing, stirring, or turbulat-ing by contact with a solid member or the flowpath of the contact liquid is altered.

SEE OR SEARCH THIS CLASS, SUB-CLASS:260 through 262, for degasifying liquid by

liquid flow modifying or mechanicalagitating.


187 And recycle or reuse of contact liquid forfurther contact:This subclass is indented under subclass 149.Process in which (a) the contact liquid is recir-culated for further contact with the fluid mix-ture or a portion thereof or (b) the contactliquid is used in another step of the process forfurther contact with the fluid mixture or a por-tion thereof.

(1) Note. The recycled or reused contact liq-uid may have been regenerated or it maybe a mixture with the removed constitu-ent.

188 After separation of liquid from contact liq-uid:This subclass is indented under subclass 187.Process in which the contact liquid is recycledor reused after another liquid constituent isremoved from the contact liquid.

(1) Note. The liquid removed from the con-tact liquid may have been originallypresent as liquid particles entrained in agas, or the liquid removed may havebeen originally present as vapors as partof a plurality of gases, in which case thevapors would have condensed to liquidbecause of the liquid contact.


December 2009

(2) Note. In order for a patent to be placedhere, the vapors sorbed by a liquid froma plurality of gases and removed fromthe liquid must be normally liquid at atemperature of 0°C and a pressure of 760mm Hg and the vapors must have con-densed to liquid (e.g., methanol(CH3OH), ethanol (C2H5OH), etc.).

SEE OR SEARCH THIS CLASS, SUB-CLASS:156 through 186, for liquid contact and

removal of a gas from a liquid.206 through 209, for separation of a liquid

constituent from the contact liquidwithout recycling or reusing the con-tact liquid.

189 And separation of solid from contact liquid:This subclass is indented under subclass 188.Process in which a solid is removed from thecontact liquid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:195, and 205, for other processes of sepa-

rating a solid from the contact liquid.

190 By liquid-liquid extraction or formation ofazeotrope:This subclass is indented under subclass 188.Process in which (a) a liquid extractant ismixed with the contact liquid in order to causeseparation of a solute from the contact liquidand then the liquid extractant with the removedsolute is separated from the contact liquid or(b) a compound that forms a mixture of con-stant boiling point with a solute in the contactliquid is added to the contact liquid and thenthe azeotropic mixture is separated from thecontact liquid.

SEE OR SEARCH CLASS:210, Liquid Purification or Separation,

subclass 634 for processes, per se, inwhich a dissolved or suspended con-stituent of a liquid is preferentiallydissolved or dispersed into a secondliquid.

191 By stripping with gas:This subclass is indented under subclass 188.Process in which the liquid constituent isremoved from the contact liquid by passing agas through or in contact with the contact liq-uid.


degasification of liquid by strippingwith gas.

207, for liquid contacting and separation ofa liquid constituent from the contactliquid by stripping with gas withoutrecycle or reuse of the contact liquid.

192 By reduction of pressure (e.g., flashing, etc.):This subclass is indented under subclass 188.Process in which the liquid constituent isremoved from the contact liquid by decreasingthe pressure acting on the contact liquid.



208, for liquid contacting and separation ofa liquid constituent from the contactliquid by reduction of pressure with-out recycle or reuse of the contact liq-uid.

193 By heating (e.g., fractional distillation, etc.):This subclass is indented under subclass 188.Process in which the liquid constituent isremoved from the contact liquid by heating thecontact liquid (e.g., fractional distillation, etc.).


degasification of liquid by heating.209, for liquid contacting and separation of

a liquid constituent from the contactliquid by heating without recycle orreuse of the contact liquid.

194 Indirect heat exchange:This subclass is indented under subclass 193.Process in which heat is transferred through awall.


1December 2009

195 After separation of solid from contact liq-uid:This subclass is indented under subclass 187.Process in which the contact liquid is recycledor reused after a solid is removed from the con-tact liquid.



196 By filtration:This subclass is indented under subclass 195.Process in which the contact liquid containingthe solid to be removed is passed through aforaminous or porous mass which separates thesolid from the liquid by entrapment and reten-tion while permitting the liquid to passthrough.

197 By gravity separation:This subclass is indented under subclass 195.Process in which the solid settles to the bottomof a mass of the contact liquid in a settling tankor the solid rises to the top of a mass of thecontact liquid in a flotation tank due to the dif-ference in density of the solid and the contactliquid, with the layer of the contact liquid con-taining the solid being separated from theremainder of the mass of contact liquid.

198 And deflection to remove liquid particlesfrom gas:This subclass is indented under subclass 187.Process in which the gas and liquid after con-tact impinge on a surface to effect an abruptchange in direction of the gas-liquid mixture orto guide the gas-liquid mixture to cause the liq-uid to drop out and remain behind while thegas flows on.

SEE OR SEARCH THIS CLASS, SUB-CLASS:216 through 222, for other processes of

liquid contacting and deflection.267 through 272, for deflection without

liquid contacting.

199 Liquid contact in plural serial stages:This subclass is indented under subclass 187.Process in which liquid and gaseous fluid mix-ture contact is effected in more than one step orzone in series.

SEE OR SEARCH THIS CLASS, SUB-CLASS:223 through 225, for liquid contact in plu-

ral serial stages without recycle orreuse of the contact liquid.


classes 267 through 280 for gas sepa-ration apparatus with gas and liquidcontact means having diverse meansfor adding the liquid.

200 Removal of solid or liquid particles fromgas:This subclass is indented under subclass 199.Process in which solid or liquid particles areremoved from a gas.

SEE OR SEARCH THIS CLASS, SUB-CLASS:202, for removal of solid or liquid particles

from gas in a single stage.

201 Reduction of pressure during liquid contact:This subclass is indented under subclass 199.Process in which pressure is decreased duringthe liquid contact.

202 Removal of solid or liquid particles fromgas:This subclass is indented under subclass 187.Process in which solid or liquid particles areremoved from a gas.

SEE OR SEARCH THIS CLASS, SUB-CLASS:200, for removal of solid or liquid particles

from gas in plural serial stages.

203 Reduction of pressure:This subclass is indented under subclass 187.Process in which pressure is decreased.


December 2009

204 And recycle of gas for further contact:This subclass is indented under subclass 149.Process in which the gaseous fluid mixture or aseparated gaseous constituent is recirculatedfor further contact with the liquid.

205 And separation of solid from contact liquid:This subclass is indented under subclass 149.Process in which a solid is removed from thecontact liquid.



206 And separation of liquid from contact liq-uid:This subclass is indented under subclass 149.Process in which a liquid constituent isremoved from the contact liquid.

(1) Note. The liquid removed from the con-tact liquid may have been originallypresent as liquid particles entrained in agas, or the liquid removed may havebeen originally present as vapors as partof a plurality of gases, in which case thevapors would have condensed to liquidbecause of the liquid contact.

(2) Note. In order for a patent to be placedhere, the vapors sorbed by a liquid froma plurality of gases and removed fromthe liquid must be normally liquid at atemperature of 0°C and a pressure of 760mm Hg and the vapors must have con-densed to liquid (e.g., methanol(CH3OH), ethanol (C2H5OH), etc.).

SEE OR SEARCH THIS CLASS, SUB-CLASS:156 through 186, for liquid contact and

removal of a gas from a liquid.188 through 194, for separation of a liquid

constituent from the contact liquidwith recycling or reusing the contactliquid.

207 By stripping with gas:This subclass is indented under subclass 206.Process in which the liquid constituent isremoved from the contact liquid by passing a

gas through or in contact with the contact liq-uid.


degasification of liquid by strippingwith gas.

191, for liquid contacting and separation ofa liquid constituent from the contactliquid by stripping with gas with recy-cle or reuse of the contact liquid.

208 By reduction of pressure (e.g., flashing, etc.):This subclass is indented under subclass 206.Process in which the liquid constituent isremoved from the contact liquid by decreasingthe pressure acting on the contact liquid.



192, for liquid contacting and separation ofa liquid constituent from the contactliquid by reduction of pressure withrecycle or reuse of the contact liquid.

209 By heating (e.g., fractional distillation, etc.):This subclass is indented under subclass 206.Process in which the liquid constituent isremoved from the contact liquid by heating thecontact liquid (e.g., fractional distillation, etc.).


degasification of liquid by heating.193 through 194, for liquid contacting and

separation of a liquid constituent fromthe contact liquid by heating withrecycle or reuse of the contact liquid.

210 On surface extending mass:This subclass is indented under subclass 149.Process in which the contact between the gas-eous fluid mixture and the liquid takes place ona material which serves to increase the area forcontact.


1December 2009


classes 290 through 300 for gas sepa-ration apparatus in which gas and liq-uid contact takes place on particulatemedia, shaped packing elements, orporous media.

211 Particulate media, fibrous media, or pack-ing elements:This subclass is indented under subclass 210.Process in which the surface extending massconsists of (a) a plurality of small, discrete sol-ids (e.g., particulate bed, etc.), (b) a mass ofslender, elongated material (e.g., a mass ofwicklike or threadlike material, etc.), or (c) amass of randomly oriented or positioned ele-ments which may be molded, machined, orformed, that possess specific advantages ofsurface availability for gas and liquid contact-ing (e.g., Raschig rings, Berl saddles, Intaloxsaddles, Pall rings, etc.).

SEE OR SEARCH CLASS:261, Gas and Liquid Contact Apparatus,

subclasses 94 through 99 for appara-tus specially adapted to produce anintimate contact between gases andliquids including a stationary porousmass of material (not a sheet). Seealso digest 72 for packing elements.

212 And cleaning of particulate media, fibrousmedia, or packing elements:This subclass is indented under subclass 211.Process in which the liquid or the separatedconstituent is removed from the particulatemedia, fibrous media, or packing elements.

213 Apertured partition member:This subclass is indented under subclass 210.Process in which the surface extending masshas one or more openings through which thegaseous fluid mixture or liquid passes in orderto increase the contact of the gas with the liq-uid (e.g., use of perforated plates, bubble captrays, mesh screens, parallel wires, parallelbars, etc.).

SEE OR SEARCH CLASS:261, Gas and Liquid Contact Apparatus,

subclasses 108 through 114.5 forapparatus specially adapted to pro-

duce an intimate contact betweengases and liquids including stationarybaffles over which the liquids flow incontact with gases. See particularlysubclass 113 for perforated bafflesand subclass 114.2 for apparatus uti-lizing bubble caps.

214 And filtration of gas:This subclass is indented under subclass 149.Process in which a gas and solid or liquid parti-cles entrained therein is passed through aforaminous or porous mass which separates thesolid or liquid particles from the gas by entrap-ment and retention while permitting the gas-eous or vaporous constituents to pass.

SEE OR SEARCH THIS CLASS, SUB-CLASS:273 through 287, for filtering without liq-

uid contact.281, for filtering with cleaning of the filter

by use of a liquid.

215 Including movement of filter:This subclass is indented under subclass 214.Process in which the filter is not stationary dur-ing filtration.

216 And deflection:This subclass is indented under subclass 149.Process in which the gaseous fluid mixture, liq-uid, or the gaseous fluid mixture and liquidafter contact (a) are impinged on a solid or liq-uid mass and the direction of flow is changedbecause of the impinging on the solid or liquidmass or (b) are contacted by a gas stream toeffect an abrupt change in direction of flow.

(1) Note. The deflection may or may notcause separation of a constituent fromthe gaseous fluid mixture.

SEE OR SEARCH THIS CLASS, SUB-CLASS:198, for other processes of liquid contact-

ing and deflection with recycle orreuse of the contact liquid.

267 through 272, for separation of a con-stituent from a gas by deflection.


December 2009

217 Liquid is in form of curtain:This subclass is indented under subclass 216.Process in which the liquid falls through openspace freely in a thin stream for gas-liquid con-tact.

218 Including movement of deflector:This subclass is indented under subclass 216.Process in which the deflection is caused by asolid mass that is not stationary during deflec-tion.

219 Including rotation of liquid, gaseous fluidmixture, or gas-liquid mixture through 360degrees in stationary apparatus:This subclass is indented under subclass 216.Process in which the liquid, gaseous fluid mix-ture, or gas-liquid mixture rotates or spinsaround an axis through 360° in an apparatusthat does not move to cause the rotating orspinning.

220 With heating or cooling:This subclass is indented under subclass 219.Process in which the gaseous fluid mixture, aseparated constituent, the contact liquid, orapparatus involved in the process is heated orcooled.

221 Deflection in plural serial stages:This subclass is indented under subclass 216.Process in which the deflection of the gaseousfluid mixture, liquid, or the gaseous fluid mix-ture and liquid after contact occurs in morethan one step or zone in series.


ral serial stages without deflection.



222 Using diverse type deflectors:This subclass is indented under subclass 221.Process in which two or more discrete deflec-tors are arranged one downstream of the other,

at least two of the deflectors being of differingtypes.

223 In plural serial stages:This subclass is indented under subclass 149.Process in which the fluid mixture is contactedwith a liquid in more than one step or zone inseries.


ral serial stages with recycle or reuseof contact liquid.



224 Liquid sprays:This subclass is indented under subclass 223.Process in which the fluid mixture is treated ineach zone or stage with liquid which has beenfinely dispersed.

225 With heating or cooling:This subclass is indented under subclass 224.Process in which the fluid mixture, a separatedconstituent, the contact liquid, or apparatusinvolved in the process is heated or cooled.

226 Gaseous fluid mixture discharged against orbeneath surface of liquid body:This subclass is indented under subclass 149.Process in which the gaseous fluid mixture tobe treated (a) impinges onto the top layer of aliquid contained in a reservoir or (b) is dis-charged beneath the top layer of a liquid.


classes 329 through 354 for gas sepa-ration apparatus having a liquid bathor reservoir for gas and liquid contact.

261, Gas and Liquid Contact Apparatus, subclasses 121.1 through 124 fordevices specially adapted to producean intimate contact between gases andliquids by means that discharges gasbeneath the surface of the liquid.


1December 2009

227 With heating:This subclass is indented under subclass 149.Process in which the fluid mixture, a separatedconstituent, the contact liquid, or apparatusinvolved in the process is heated.

228 With cooling:This subclass is indented under subclass 149.Process in which the fluid mixture, a separatedconstituent, the contact liquid, or apparatusinvolved in the process is cooled.

229 Cooling before liquid contacting:This subclass is indented under subclass 228.Process in which the contact with a liquidoccurs after the cooling.

230 Inorganic gas, liquid particle, or solid parti-cle sorbed (e.g., vapor, mist, dust, etc.):This subclass is indented under subclass 149.Process in which an inorganic gas, liquid parti-cle, or solid particle is separated from the plu-rality of gases or the gas with entrained liquidor solid particles by the contact with a liquid.

(1) Note. For purposes of classification inthis area, “inorganic” compounds or ele-ments are those that would fall withinthe definition of Class 423. For example,the cyanides (CN joined only to a metalor to hydrogen) and the carbon oxidesare found in the indented subclasses.

231 Water sorbed:This subclass is indented under subclass 230.Process in which water is separated.

232 Nitrogen or nitrogen containing compoundsorbed:This subclass is indented under subclass 230.Process in which nitrogen (N2) or a nitrogencontaining compound is separated.

233 Halogen or halogen containing compoundsorbed:This subclass is indented under subclass 230.Process in which a halogen (i.e., fluorine (F),chlorine (Cl), bromine (Br), iodine (I), astatine(At)) or a halogen containing compound is sep-arated.

234 Metal or metal containing compoundsorbed:This subclass is indented under subclass 230.Process in which a metal or a metal containingcompound is separated.

235 Sulfur or sulfur containing compoundsorbed:This subclass is indented under subclass 230.Process in which sulfur (S) or a sulfur contain-ing compound is separated.

236 Carbon dioxide sorbed:This subclass is indented under subclass 230.Process in which carbon dioxide (CO2) is sepa-rated.

237 Organic gas, liquid particle, or solid particlesorbed (e.g., vapor, mist, dust, etc.):This subclass is indented under subclass 149.Process in which an organic gas, liquid parti-cle, or solid particle is separated from the plu-rality of gases or the gas with entrained liquidor solid particles by the contact with a liquid.

(1) Note. For purposes of classification inthis area, “organic” compounds are thosethat would fall within the definitions ofClass 260.

238 Alkyne sorbed (e.g., acetylene, etc.):This subclass is indented under subclass 237.Process in which an alkyne (i.e., alkine) is sep-arated (e.g., acetylene, etc.).

239 Cyclic compound sorbed:This subclass is indented under subclass 237.Process in which a cyclic compound is sepa-rated.

240 Alkene sorbed:This subclass is indented under subclass 237.Process in which an alkene (i.e., olefin) is sepa-rated.

241 DEGASIFICATION OF LIQUID:This subclass is indented under the class defini-tion. Process in which a gas is removed from aliquid.

(1) Note. In order for a patent to be placedhere, the gas removed from the liquidmust be normally gaseous at a tempera-


December 2009

ture of 0°C and a pressure of 760 mm Hg(e.g., hydrogen sulfide (H2S), carbonmonoxide (CO), carbon dioxide (CO2),ethane (C2H6), ammonia (NH3), etc.). If,however, a constituent is at a tempera-ture above its boiling temperature for aparticular pressure, then the constituentis presumed to be a gas, and a patent to aprocess for removing the constituent willbe placed here when the constituent isinitially present in gaseous phase in theliquid and is removed from the liquid asa gas.

(2) Note. The removal of a volatile organiccompound (e.g., ethanol (C2H5OH), gas-oline, etc.) from a liquid is not taken tobe degasification of a liquid for Class 95when the volatile organic compound isinitially present as a liquid mixed withanother liquid. The removal of a volatileorganic compound from a liquid may befound in Class 210 for liquid purificationor separation or Class 203 for separatorydistillation processes.


liquid by use of sound waves.46, for processes of degasification of a


90 through 148, for processes of degas-ification of a liquid by use of a solidsorbent.

156 through 186, for processes of contact-ing a gas with a liquid and degasifica-tion of the contact liquid.


classes 155 through 220 for degasify-ing means for liquid.

203, Distillation: Processes, Separatory, appropriate subclasses for processesfor separating a liquid mixture byvaporizing and condensing at least aportion thereof to isolate in the con-densed liquid (distillate) or in theunvaporized portion (residue) a com-paratively pure compound that was

present as such in the original mix-ture.

210, Liquid Purification or Separation, appropriate subclasses for processesof removing a volatile organic com-pound from a liquid wherein the vola-tile organic compound is initiallypresent as a liquid mixed with anotherliquid.

242 Defoaming:This subclass is indented under subclass 241.Process in which a frothy or sudslike disper-sion is resolved or broken into separate fluidphases.


defoaming a liquid.


classes 176 through 180 for defoam-ing apparatus.

516, Colloid Systems and Wetting Agents;Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 115 through134 for processes of or compositionsfor or subcombination compositionsfor the breaking of or inhibiting offoam colloid systems, when generi-cally claimed or when there is no hier-archically superior provision in theUSPC for the specifically claimed art.

243 Plural successive degassing treatments:This subclass is indented under subclass 241.Process in which the liquid is subjected to morethan one degasifying step, each step occurringat a different time than another step.

244 Boiler feed water degassing:This subclass is indented under subclass 243.Process in which the liquid that is degasified isthe feed going to a steam generator, whetherraw water or condensed steam.

245 By stripping with gas:This subclass is indented under subclass 243.Process in which in at least one of the degasify-ing steps the gas is removed from the liquid by


1December 2009

passing a gas through or in contact with the liq-uid.


placing separated constituents from achromatographic column comprisinga liquid solvent on a solid base.

159 through 171, for contacting a gas witha liquid and degasifying the contactliquid by stripping with gas.



246 And reduction of pressure (e.g., flashing,etc.):This subclass is indented under subclass 245.Process in which the pressure acting on the liq-uid is decreased.

(1) Note. The pressure reduction may beused in a separate step in order toremove gas from the liquid in addition tothe step of removing gas from the liquidby stripping with gas, or the pressurereduction may be used in order to aid theremoval by stripping with gas.

SEE OR SEARCH THIS CLASS, SUB-CLASS:160 through 164, for contacting a gas with

a liquid and degasifying the contactliquid by stripping with gas andreduction of pressure.

247 through 250, and 266, for degasifica-tion of liquid by reduction of pressure.



247 By reduction of pressure (e.g., flashing, etc.):This subclass is indented under subclass 243.Process in which in at least one of the degasify-ing steps the gas is removed from the liquid bydecreasing the pressure acting on the liquid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:172 through 177, for contacting a gas with

a liquid and degasifying the contactliquid by reduction of pressure.




248 And liquid flow modifying or mechanicalagitating:This subclass is indented under subclass 247.Process in which the liquid is mixed, stirred, orturbulated by contact with a solid member orthe flow path of the contact liquid is altered.

(1) Note. The liquid flow modifying ormechanical agitating may be used in aseparate step in order to remove gasfrom the liquid in addition to the step ofremoving gas from the liquid by reduc-tion of pressure, or the liquid flow modi-fying or mechanical agitating may beused in order to aid the removal byreduction of pressure.

SEE OR SEARCH THIS CLASS, SUB-CLASS:185, for contacting a gas with a liquid and

degasifying the contact liquid by liq-uid flow modifying or mechanicalagitating.

260 through 262, for degasifying liquid byliquid flow modifying or mechanicalagitating.

249 And heating:This subclass is indented under subclass 248.Process in which the liquid or the gas is heated.

(1) Note. The heating may be used in a sepa-rate step in order to remove gas from theliquid in addition to the step of removinggas from the liquid by reduction of pres-sure or liquid flow modifying, or theheating may be used in order to aid theremoval by reduction of pressure or liq-uid flow modifying.


December 2009


degasification of the contact liquid byheating.

251 through 252, for degasifying liquid byheating.



250 And heating:This subclass is indented under subclass 247.Process in which the liquid or the gas is heated.

(1) Note. The heating may be used in a sepa-rate step in order to remove gas from theliquid in addition to the step of removinggas from the liquid by reduction of pres-sure, or the heating may be used in orderto aid the removal by reduction of pres-sure.



251 through 252, for degasifying liquid byheating.



251 By heating:This subclass is indented under subclass 243.Process in which in at least one of the degasify-ing steps the gas is removed from the liquid byheating the liquid.



247 through 250, for degasifying liquid byreduction of pressure and heating.



252 And liquid flow modifying or mechanicalagitating:This subclass is indented under subclass 251.Process in which the liquid is mixed, stirred, orturbulated by contact with a solid member orthe flow path of the contact liquid is altered.

(1) Note. The liquid flow modifying ormechanical agitating may be used in aseparate step in order to remove gasfrom the liquid in addition to the step ofremoving gas from the liquid by heating,or the liquid flow modifying or mechani-cal agitating may be used in order to aidthe removal by heating.



260 through 262, for degasifying liquid byliquid flow modifying or mechanicalagitating.

253 Emulsion breaking or multiple liquid sepa-rating:This subclass is indented under subclass 241.Process in which two liquids are separated, oneof which (a) is originally finely dispersed in theother, as in an emulsion, or (b) is mixed in andflows with the other.

SEE OR SEARCH THIS CLASS, SUB-CLASS:188 through 194, and 206-209, for con-

tacting a gas with a liquid and separa-tion of the liquid from the contactliquid.

SEE OR SEARCH CLASS:55, Gas Separation, subclass 421 for gas

separation apparatus which has meansto separate a liquid from a mixturewith one or more additional liquids.


1December 2009

96, Gas Separation: Apparatus, sub-classes 182 through 186 for degasify-ing means for liquid which has meansto separate a liquid from a mixturewith one or more additional liquids.

210, Liquid Purification or Separation,appropriate subclasses for liquid puri-fication or separation, and see particu-larly subclass 708 for emulsion break-ing.

516, Colloid Systems and Wetting Agents;Subcombinations Thereof; Processesof Making, Stabilizing, Breaking, orInhibiting, subclasses 135 through197 for processes of or compositionsfor or subcombination compositionsfor the breaking of or inhibiting ofemulsion colloid systems, by additionof chemical agent or by action ofphysical agent, when genericallyclaimed or when there is no hierarchi-cally superior provision in the USPCfor the specifically claimed art.

254 And subsequent handling of evolved gas,stripping gas, or residue liquid:This subclass is indented under subclass 241.Process in which the removed gas, a strippinggas, or the remaining liquid is further treated orused in some manner involving more than mereremoval from the system.

255 Evolved gas removed by sweep gas:This subclass is indented under subclass 254.Process in which a purge gas is used to carryoff the removed gas.

256 For indirect heat exchange:This subclass is indented under subclass 254.Process in which the removed gas, the strip-ping gas, or the remaining liquid is used totransfer heat to or to accept heat from anymaterial through a solid wall.

257 Gas condensed:This subclass is indented under subclass 256.Process in which the removed gas or the strip-ping gas is the heat exchange medium and iscondensed to liquid.

258 Gas recycled or further separated:This subclass is indented under subclass 254.Process in which (a) the removed gas is used tofurther strip gas from the liquid, (b) the strip-

ping gas is recovered and is used for furtherstripping of gas from the liquid, or (c) the gas issubjected to an additional separating treatment.

259 Liquid further separated:This subclass is indented under subclass 254.Process in which the remaining liquid is sub-jected to an additional separating treatment.

260 By liquid flow modifying or mechanical agi-tating:This subclass is indented under subclass 241.Process in which the gas is removed from theliquid by mixing, stirring, or turbulating bycontact with a solid member or the flow path ofthe liquid is altered.



248 through 249, and 252, for plural suc-cessive liquid degassing treatmentswhich include liquid flow modifying.

261 Centrifugal force:This subclass is indented under subclass 260.Process in which the gas is removed from theliquid by the effect of centrifugal action whichcauses the liquid with gas entrained therein toassume a rapid arcuate or circular movement.

262 Impinging on baffle:This subclass is indented under subclass 260.Process in which the gas is removed from theliquid by causing the liquid with gas entrainedtherein to contact a solid surface in the flowpath of the process in order to redirect or alterthe flow path and to cause separation of the gasfrom the liquid.

263 By stripping with gas:This subclass is indented under subclass 241.Process in which the gas is removed from theliquid by passing a gas through or in contactwith the liquid.


placing separated constituents from a


December 2009

chromatographic column comprisinga liquid solvent on a solid base.

159 through 171, for liquid contacting anddegasification of the contact liquid bystripping with gas.

245 through 246, for plural successive liq-uid degassing treatments whichinclude stripping with a gas.




265 Nitrogen is stripping gas:This subclass is indented under subclass 263.Process in which the stripping gas is nitrogen(N2).

266 By reduction of pressure (e.g., flashing, etc.):This subclass is indented under subclass 241.Process in which the gas is removed from theliquid by decreasing the pressure acting on theliquid.


contacting and degasification of liquidby stripping with gas in which there isreduction of pressure.

172 through 177, for liquid contacting anddegasification of liquid by reductionof pressure.




267 DEFLECTING:This subclass is indented under the class defini-tion. Process in which solid or liquid particlesare removed from a gas by causing the gas andsolid or liquid particles entrained therein (a) to

contact a solid surface to effect an abruptchange in direction of the gas which (i) causesthe solid or liquid particles to drop out andremain behind while the gas flows on or (ii)causes the solid or liquid particles to move tothe outer periphery of a rotating gas stream in aconcentrated layer to permit such layer to beseparated from the gas with fewer or noentrained particles or (b) to contact a gasstream to effect an abrupt change in directionof the gas which causes the solid or liquid par-ticles to drop out and remain behind while thegas flows on.


ing a plurality of gases into constitu-ent parts by making use of differencesin molecular velocity, density, ormomentum of gases.

198, for processes of contacting a gas witha liquid and deflection to remove liq-uid from gas with recycle of contactliquid.

216 through 222, for processes of contact-ing a gas with a liquid and deflection.


through 465 for deflectors.

268 And filtering:This subclass is indented under subclass 267.Process in which a gas and solid or liquid parti-cles entrained therein is passed through aforaminous or porous mass which separates thesolid or liquid particles from the gas by entrap-ment and retention while permitting the gas-eous or vaporous constituents to pass.

SEE OR SEARCH THIS CLASS, SUB-CLASS:273 through 287, for filtering without

deflection.

269 Centrifugal force:This subclass is indented under subclass 267.Process in which the solid or liquid particlesare removed from the gas by the effect of cen-trifugal action causing the gas and the solid orliquid particles entrained therein to assume arapid arcuate or circular movement, with thismovement causing the constituents of the mix-


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ture to separate into more or less distinct lay-ers, depending upon the density of theconstituents.


ing a plurality of gases into constitu-ent parts by making use of centrifugalforce.

270 Created by rotating equipment:This subclass is indented under subclass 269.Process in which the centrifugal force is causedby a rotating element moving around an axis.

SEE OR SEARCH THIS CLASS, SUB-CLASS:35, for processes of separating a plurality

of gases into constituent parts by mak-ing use of centrifugal force in rotatingequipment.

271 Tangential gas inflow (e.g., cyclone, etc.):This subclass is indented under subclass 269.Process in which the gas enters deflectingapparatus in a path other than one that inter-sects or is parallel to the longitudinal axis ofthe apparatus.

272 Tortuous flow path:This subclass is indented under subclass 267.Process in which the gas passes through anapparatus in a path that is repeatedly turned orbent.

273 FILTERING:This subclass is indented under the class defini-tion. Process in which a gas and solid or liquidparticles entrained therein are passed through aforaminous or porous mass which separates thesolid or liquid particles from the gas by entrap-ment and retention while permitting the gas-eous or vaporous constituents to pass through;and subcombinations of gas filtration processesthat do not result in separation (e.g., cleaningof a filter, etc.) when the subcombinations arenot provided for elsewhere.

(1) Note. A filter (particulate solids or other)has no “chemical” affinity for a constitu-ent of a fluid mixture. The separation inthe case of a filter depends on a mechan-ical entrapment of solid or liquid parti-

cles because of their relatively large sizecompared with the interstices or spacesbetween individual elements of the filter.The retained particles can be removed bybrushing, wiping, shaking, or similarmechanical action.

A solid sorbent is a solid material whichseparates a constituent (e.g., a gas, vapor,etc.) from a fluid mixture containingsuch constituents in a “quasi-chemical”manner. The action in most instances isthat of selective retention (i.e., the sor-bent removes only the part of the fluidmixture for which it has the greatestaffinity). The retained constituent cannotbe removed by shaking, brushing, orsimilar mechanical action, but generallycan be removed by heating, pressurereduction, or use of a stripping or denud-ing fluid.

SEE OR SEARCH THIS CLASS, SUB-CLASS:214 through 215, for processes of contact-

ing a gas with a liquid and filtration ofthe gas.

268, for processes of filtering with deflec-tion.

SEE OR SEARCH CLASS:55, Gas Separation, appropriate sub-

classes for filters.

274 Through particulate solids:This subclass is indented under subclass 273.Process in which the mass comprises a plural-ity of small, distinct, separate, nonfilamentoussolids.


through 519 for filtering apparatusincluding means for securing orretaining a mass of particulate solidsduring use as a filter medium.

275 Moving bed:This subclass is indented under subclass 274.Process in which a bed of solid particles is con-stantly in motion during the separation.


December 2009

SEE OR SEARCH CLASS:55, Gas Separation, subclass 474 for

apparatus in which a bed of particu-late solids is agitated or caused to bemoved to different zones during nor-mal use thereof.

276 With cleaning of filter bed:This subclass is indented under subclass 274.Process in which the separated solid or liquidparticles are removed from the particulate sol-ids.

277 Moving filter:This subclass is indented under subclass 273.Process in which the filter is in motion duringthe separation.

278 With cleaning of filter:This subclass is indented under subclass 273.Process in which the separated solid or liquidparticles are removed from the filter.


through 305 for cohesive filter clean-ing means.

279 By use of gas:This subclass is indented under subclass 278.Process in which the separated solid or liquidparticles are removed from the filter by con-tacting the filter with a gas, usually in a direc-tion opposite that of the process fluid flowduring separation.


through 303 for cohesive filter clean-ing means using pneumatic reverseflushing.

280 Pulsed gas flow:This subclass is indented under subclass 279.Process in which the pressure of the gas thatcontacts the filter in order to remove the sepa-rated solid or liquid particles increases anddecreases periodically.

281 By use of liquid:This subclass is indented under subclass 278.Process in which the separated solid or liquidparticles are removed from the filter by con-

tacting the filter with a liquid, usually in adirection opposite that of the process fluid flowduring separation.


233 for gas separation apparatus hav-ing means using liquid to clean a fil-ter.

282 By mechanical manipulation:This subclass is indented under subclass 278.Process in which the separated solid or liquidparticles are removed from the filter by effect-ing filter motion or a relative movement amongportions thereof whereby accumulations areremoved or prevented.


through 305 for cohesive filter clean-ing means using filter manipulation.

283 With heating of filter:This subclass is indented under subclass 273.Process in which the filter is heated.

284 And reduction of pressure:This subclass is indented under subclass 273.Process in which the pressure acting in the pro-cess is decreased.

285 Coated or chemically treated filter:This subclass is indented under subclass 273.Process in which the filter is coated or in whichthe filter is treated with a chemical before itsuse for filtration.

286 Plural separate media:This subclass is indented under subclass 273.Process in which at least two filters that arespaced apart are used.


through 489 for two or more spacedfilters in a flow line or casing.

287 In series:This subclass is indented under subclass 286.Process in which the filters are placed one afterthe other in succession.


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SEE OR SEARCH CLASS:55, Gas Separation, subclass 485 for three

or more serially spaced filters.

288 HEAT EXCHANGING:This subclass is indented under the class defini-tion. Process in which there is transfer of heat.

(1) Note. The heat transfer steps must bepart of a larger process containing sub-ject matter for Class 95. If the only sepa-ration involved is conducted by indirectheat transfer steps, then classification inClass 165 is proper. However, Class 95does take cold wall-hot wall thermal dif-fusion and condensing a constituent of agas to the solid state.

SEE OR SEARCH CLASS:62, Refrigeration, appropriate subclasses

for specialized refrigeration arrange-ments. See the class definition ofClass 95 for an amplification of theline.

165, Heat Exchange, appropriate sub-classes for heat exchange apparatus orprocesses. See the class definition ofClass 95 for an amplification of theline.

289 Cold wall-hot wall thermal diffusion:This subclass is indented under subclass 288.Process in which the separation occurs by con-tacting the plurality of gases with plural sur-faces of different temperatures to causemigration of gaseous constituents to one sur-face or another.

(1) Note. This subclass takes specific refrig-erating steps for maintaining the coolerwall at the lower temperature.


221 for corresponding apparatus. Pat-ents are not cross-referenced fromClass 96, subclass 221 to this subclassbased only on disclosure. Therefore,relevant disclosures of gas separationprocesses may be found in the appara-tus area.

290 Condensing to solid:This subclass is indented under subclass 288.Process in which the separated constituent iscaused to pass to the solid state.

291 MISCELLANEOUS:This subclass is indented under the class defini-tion. Process not otherwise provided forabove.

CROSS-REFERENCE ART COLLECTIONS

The following cross-reference art collections represent acollection of patents found elsewhere in the classifica-tion of this class, but merit isolation for aid in searchingcertain concepts which do not form appropriate basesfor the placement of original patents. These concepts areas given in the titles and definitions of the subclassescross-reference art collections listed hereunder.

The cross-reference patents contained in these collec-tions may be of further assistance to the searcher, eitheras a starting point in searching this class or as an indica-tion of further related fields of search inside or outsidethe class. Thus, there is provided here a further path ofaccess for retrieval of a limited number of types of dis-closure.

(1) Note. Disclosures are placed in thesecross-reference art collections for theirvalue as references and as leads toappropriate main or secondary fields ofsearch, without regard to their originalclassification or their claimed subjectmatter.

(2) Note. The disclosures found in the fol-lowing cross-reference art collectionsare only examples of the indicated sub-ject matter, and in no instance do theyrepresent the entire extent of the priorart.

900 SOLID SORBENT:Solid sorbent as provided for use in this classin which particular details are disclosed aboutthe solid sorbent.

(1) Note. Merely stating that a solid sorbent,activated carbon (C), or molecular sieveis used is insufficient to cause a patent tobe placed here.


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SEE OR SEARCH CLASS:502, Catalyst, Solid Sorbent, or Support

Therefor: Product or Process of Mak-ing, appropriate subclasses for solidsorbents.

901 Activated carbon:This subclass is indented under cross-referenceart collection 900. Solid sorbent as providedfor use in this class in which particular detailsare disclosed about the activated carbon (C),which is a highly absorbent carbon obtained byheating granulated charcoal, obtained fromvegetable matter, to exhaust contained gases.

902 Molecular sieve:This subclass is indented under cross-referenceart collection 900. Solid sorbent as providedfor use in this class in which particular detailsare disclosed about the molecular sieve whichis usually a natural or synthetic metal alumi-num silicate.

(1) Note. The separation is similar to filtra-tion in that the interstices of the molecu-lar sieve particle accept and retain onlythose molecules which are smaller insize than the interstices.

903 Carbon:This subclass is indented under cross-referenceart collection 902. Solid sorbent as providedfor use in this class in which the molecularsieve material is carbon (C).

END

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