Blackmer Lpg Handbook 500

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LIQUEFIED GAS HANDBOOK BULLETIN 500-001 Section 500 Effective November 2001 Replaces October 1969 Practical suggestions on the design and installation of handling systems for propane, butane, anhydrous ammonia and similar liquefied gases

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Blackmer Lpg Handbook 500

Transcript of Blackmer Lpg Handbook 500

Page 1: Blackmer Lpg Handbook 500

LIQUEFIED GAS HANDBOOK

BULLETIN 500-001Section 500Effective November 2001Replaces October 1969

Practical suggestions on the design and installation of handling systems for propane,butane, anhydrous ammonia and similar liquefied gases

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This handbook is about Blackmer lique-fied gas pumps and compressors, theirinstallation and operation. It out- lines several practical suggest-tions and guidelines that canbe used in the design ofnew trucks and plants aswell as the troubleshoot-ing of older installations.It is not, nor is it intendedto be, a treatise on theentire LPG industry. Thereare many excellent publica-tions that cover in detail thevarious other specializedphases of this business.

Before installing propane equipmenton any mobile vehicle or in a perma-nent location, review the requirementsof N.F.P.A. Pamphlet No. 58 "Standardfor the Storage and Handling ofLiquefied Petroleum Gases."

You can obtain a copy from:National Fire Protection Association1 Batterymarch ParkQuincy, MA 02269-9101Telephone: 1-800-344-3555web: www.nfpa.org

This pamphlet is generally accepted byregulatory authorities and is the indus-try guide to safety in equipment andhandling procedures. In addition,check state laws and ordinances onthe subject. Equipment on vehiclesused in interstate service must complywith applicable requirements of theDepartment of Transportation.

Bulletin 500

www.blackmer.comInformation for all Blackmer products, both present and past models, isavailable at our website. Specification Sheets, Parts Lists, InstructionManuals and more are all available worldwide 24 hours a day.

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Table of Contents

About Blackmer 2General Characteristics of Liquefied Gas 3Positive Displacement Pumps 4Compressors 6Propane Installations 12Delivery Systems on Bobtail Trucks 15Delivery Systems on Transports 24Stationary Motor-Driven Pumps 27Vaporizer/Standby Plant Applications 29Appendix 31

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In 1903 Robert Blackmer, inventor ofthe first Rotary Vane pump, success-fully launched a new technology (slid-ing vane pumps) effectively settingvaluable pumping standards for yearsto come for pump companies aroundthe world. For nearly a century,Blackmer has continued to strengthenits commitment of providing qualityproducts to its valued customers.

Meeting customer’s challengesthrough a combination of expertise,dedication and support, allowsBlackmer to provide the most effectiveproducts with the information cus-tomer’s need to choose the rightproduct for their applications. It is thepeople at Blackmer that make thecompany what it is today. With adiverse range of market segments andexperts in the field, Blackmer takesgreat pride in its services and productsavailable worldwide.

Blackmer has five manufacturing facili-ties located around the world: GrandRapids, Michigan, Claremore,Oklahoma, Oklahoma City, Oklahoma,Ward Hill, Massachusetts and Auxerre,France. Each facility is fully equippedwith the latest technology and trainedtechnicians needed to provide prod-ucts to meet the industries highestglobal standards with local responsive-ness.

Blackmer has two research and designlocations: Grand Rapids, MI USA andAuxerre, France. These locations workaround the clock testing not only newproducts, but also changes andadvancements made to existing prod-ucts. Experts in the field are continu-ously providing one-on-one producttraining throughout the world.Blackmer believes strongly in its team,whose purpose is to service its cus-tomer’s needs through years of experi-ence and longevity in the workforce.

Blackmer has become a global compa-ny, supplying markets around theworld with expert flow-technologyapplications. Blackmer is quick torespond to the industry’s rapidadvances, through constantly reengi-neering its products to include newinnovations.

However, Blackmer is about more thanthe latest, cutting-edge technology.The employees at Blackmer worktogether as a team in order to meetcustomers’ ever-evolving needs withkeen knowledge and insight. Blackmerprovides outstanding service thatenhances its customer’s business fromsite training to expert engineering sup-port. The customer is always the firstpriority at Blackmer.

About Blackmer

Mission Statement

To provide advanced flow solutions for

applications in the chemical, refined fuels,

food/sanitary, oilfield, wastewater, pulp

and paper, transport and military

/marine industries. Through product tech-

nology, total life cycle cost value, an inter-

national manufacturing presence and glob-

al, distribution channels, we strive to deliv-

er our products and services with the

quality, expertise and efficiency our cus-

tomers deserve.

PRODUCTS LG and LGL Sliding Vane PumpsThese ductile iron pumps, available in 1” to 4" sizes are all UL listed for LPG and Anhydrous Ammonia Service. Models areavailable for motor fueling, cylinder filling, vaporizers, general transfer and truck loading/offloading.BV Bypass ValvesAll positive displacement pumps are to be fitted with a back-to-tank bypass valve. To serve that purpose Blackmer bypassvalves are all ductile iron and available in 1.25 to 2" sizes.Hydrive Hydraulic CoolersHydraulic drive systems for truck mounted pumps are becoming more and more popular. The Blackmer Hydrive HydraulicCoolers allow these systems to operate more efficiently.LB Compressors for LPG and NH3 TransferThese ductile iron compressors are available in four sizes to meet any application. Compressors are especially well suited forunloading rail cars, evacuating cylinders and tanks and anywhere vapor recovery is required.

In addition to products available for the transfer of liquefied gases, Blackmer manufactures a wide range of products for use inmany industries and markets worldwide:-Sliding Vane Pumps -System One Centrifugal Pumps -DMX Air Elimination Systems-Abaque Peristaltic Hose Pumps -HD Industrial Process Compressors -HR Gear Reducers-Tarby Progressing Cavity Pumps -Enterprise Rotary Vane Compressors -Hand Pumps-Eccentric Disc Pumps -Typhoon &Mistral Screw Compressors -Labyrinth Seals for Pumps

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General Characteristics of Liquefied GasLPG is an abbreviation for "liquefiedpetroleum gas" and encompasses sev-eral products in the hydrocarbon fami-ly; compounds composed of carbonand hydrogen of varying molecularstructures. Propane and butane arethe two best known hydrocarbons thatare used as fuel in homes, businessesand industries. In the internationalmarkets, LPG predominantly refers to apropane-butane mixture. These mixesmay vary in composition from onesthat are predominantly butane to oneswhich propane is the principal con-stituent.

LPG, whether butane or propane, isunique in that it can be transportedand stored as a liquid but whenreleased it will vaporize and burn as agas. Also, LPG can easily be changedfrom either liquid state or gas state.No other commercial fuel has thesecharacteristics. Natural gas, for exam-ple, cannot be transported in a tank inany meaningful quantities unless it iseither compressed to extremely highpressures or chilled to -259°F (-126°C), at which point it liquefies.Even when compressed, it containsonly a fraction of the useful energy ofthe identical volume of liquid-stateLPG.

When liquefied, LP gases are always attheir boiling point at normal tempera-tures. The slightest drop in pressureor the least addition of heat will causethem to boil and give off vapor or gas.This characteristic becomes criticalwhen considering the transfer of lique-fied gases from one tank to another.Being a liquefied gas, LPG must bestored in an enclosed container underpressure. The fluid in a tank is in stateof equilibrium with the gas vapors ontop of the liquid providing the tankpressure to keep the liquid from boil-ing.

Appendix A shows a chart outliningthe physical properties of propane andbutane. The specific gravities of theliquids are just over half that of water.This means a gallon of propane orbutane weighs only half the weight ofa gallon of water. Also, propane andbutane have viscosity of about 0.1centipoise, which make them approxi-mately 10 times thinner than water.This property makes LPG a difficultfluid to pump since a low viscosityfluid is harder to seal and preventpump slippage.

The single significant differencebetween propane and butane is theirboiling points, the temperature atwhich each will vaporize. Butane boilsat approximately +32°F (0°C), propaneat -44°F (-42°C) at atmospheric pres-sure. Therefore, at 0°F (-18°C), butanewill not vaporize at atmospheric pres-sure while propane will. Consequently,at any given temperature, the pressurefor a propane vessel will be higherthan a butane vessel. Refer to chart inthe Appendix B titled, "Vapor Pressureof Liquefied Gases."

LPG is inherently a safe fuel. Twoprime factors contribute to LPG safety;one is its narrow limits of flammability,the other is the fact that the containerin which it is stored is extremelystrong and airtight. If the confined gascannot escape it can't burn. LPG hasnarrower limits of flammability thanmost fuels. For propane, the respec-tive limits are 2.4% and 9.6%. Thismeans that when the concentration ofLPG in air is less than about 2.4% ormore than 9.6%, the mixture will notsupport combustion.

PROPERTIES OF LPGThe following properties of LPG should be understood for the purpose of promoting safety in usage and for intelligentaction in handling this fuel:1. The gas or vapor is heavier than air.2. The gas or vapor will diffuse into the atmosphere very slowly unless the wind velocity is high.3. Open flames will ignite air-gas mixtures which are within the flammable limits.4. Gas-air mixtures may be brought below the flammable limit by mixing with large volumes of nitrogen, carbon dioxide,steam or air.5. Fine water sprays reduce the possibility of igniting gas-air mixtures.6. The vapor pressure of this fuel is greater than gasoline. It is safely stored only in closed pressure vessels designed, con-structed and maintained according to appropriate regulations and equipped with safety devices as required.7. Liquid in open vessels will evaporate to form combustible mixtures with air even if the ambient temperature is manydegrees below the boiling point.8. The rapid removal of vapor from the tank will lower the liquid temperature and reduce the tank pressure.9. The liquids will expand in the storage tank when atmospheric temperature rises. Storage tanks must never be filledcompletely with liquid. Refer to NFPA 58 for storage tank filling density.10. Liquid drawn from the storage tank will cause freeze burns on contact. This is due to the rapid absorption of heat bythe liquid upon vaporization in the open.11. Condensation will occur in gas (vapor) distribution lines when surrounding temperatures are below the boiling point ofthe liquid.12. Liquefied petroleum gases are excellent solvents of petroleum products and rubber products. Special pipe joint com-pound and rubber substitutes are available for use in distribution.

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Positive Displacement PumpsThe pump is probably the oldest fluid transfer device known. At least two typesdate from early recorded history: (1) the undershot-bucket waterwheels ornorias, used in Asia and Africa 3,000 years ago and still common today and (2)Archimedes' screw pump (around 250 BCE) still being manufactured today tohandle solid-liquid mixtures.

A pump is a device for transferring fluids; but if it transfers gases (or vapors),three different terms may be used depending upon the pressure rise achieved.Up to about 1 psi pressure rise a gas pump is called a fan; between 1-40 psi it iscalled a blower; and above 40 psi it is called a compressor. In addition to trans-ferring fluid, a pump also is a device which adds energy to a fluid. There are twobasic types of pumps, positive-displacement and dynamic or momentum-changepumps. There are several billion of each type in use around the world today.

Positive-displacement (PD) pumps have a moving boundary which forces fluidalong by volume changes. A cavity opens and fluid is admitted through an inlet.The cavity is then closed and fluid is squeezed through an outlet. The classicexample is the mammalian heart, but mechanical versions are in wide use. PDpumps may be classified into two basic groups; reciprocating and rotary. Bothsliding vane and gear pumps are considered rotary pumps.

All PD pumps provide a nearly constant flow rate over a wide range of pressurerises, while the dynamic (centrifugal) pump gives uniform pressure rise over arange of flow rates. A PD pump is appropriate for high pressure rise and lowflow rate and its' greatest advantage is the capability to handle some quanti-ty of entrained vapors.

Blackmer manufactures a Sliding Vane pump specifically designed for LPG appli-cations. A sliding vane pump consists of a slotted rotor attached to a rotatingshaft. Vanes are fitted in the rotor slots and freely slide in and out during opera-tion. An eccentric cam profile is machined into the liner, forming the pumpchamber.

As the rotor turns, the vanes slide out of the slots and ride along the liner. Atthe intake port fluid is drawn into the pumping chamber which is formed byrotor and liner surfaces. A volume of fluid, trapped between two vanes, ispushed along the pumping chamber. At the outlet port, the vanes slide backinto the vane slot and the fluid is squeezed out the discharge piping.

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Figure 1

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As mentioned on the previous page, propane is easily converted from a liquid to a gas, which can be advantageous.However, this property also classifies propane as a highly volatile fluid. The volatility of a liquid is a measure of its ability toremain a liquid at atmospheric temperature and pressure. Water is a stable fluid. It is this volatility that makes LPG so dif-ficult to pump.

Figure 2 illustrates what happens when you transfer liquefied gas from one tank to another. As the liquid level drops, thevapor above expands and its temperature and pressure drop. Immediately, the liquid begins to boil creating vapor bub-bles. The velocity of liquid entering the intake pipe carries some of these gas bubbles with it. Each restriction in the intakepiping drops the pressure of the liquid-vapor mixture causing the vapor bubbles to expand and causing more boiling andmore vapor bubbles to form.

Vapor causes an adverse effect on both pump life and performance. Vapor bubbles prevent liquid from completelyfilling the pumping chamber cavity, which results in reduced pump capacity. Excessive vapor in the suction lines willcause large pressure spikes, which affects vane actuation and results in increased noise levels. The vanes will rapidlybounce on and off the liner. Also, excessive vapor will prevent liquid from cooling and lubricating the mechanical sealface. Without a liquid film, the seal faces will rapidly wear and lead to premature seal failure.

A globe valve is illustrated in Figure 2 because it increases the amount of vaporization. We recommend full port ball valveor gate type valves for minimum vaporizing effect.

Some vaporization will occur whenever liquefied gasses are pumped. Proper system design will minimize the amount ofvapor formed and significantly increase the pump's performance and service life.

EFFECT OF VAPORIZATION ON PUMP PERFORMANCE

Figure 2

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As mentioned in the pump section, adevice which pumps a gas at differen-tial pressure above 40 psia is termed acompressor. Like pumps, compressorsare classified into two basic classes,positive displacement and dynamic. Apositive displacement compressorcaptures a fixed volume of vapor orgas, compresses the volume and thendischarges the gas into the dischargeline.

A piston type compressor is classifiedas a reciprocating positive displace-ment compressor. Other positive dis-placement compressor types arescrew, sliding vane, wobble plate,diaphragm or lobe.

A vertical compressor orients thecylinders in the vertical plane, result-ing in a machine requiring a minimumamount of floor space. Horizontal, "V"or "W" configurations are also on themarket.

Compressors

A single-stage compressor draws gasfrom the suction line into the cylin-der(s), compresses it and discharges itinto the discharge line. Only onestage of compression is involved.

A two-stage compressor draws gasfrom the suction line into the firststage cylinder, compresses it and dis-charges the gas into a second stagecylinder, where it is compressed fur-ther and pushed into the dischargeline. The gas is compressed twice,raising it to a higher pressure than canbe done with a single-stage compres-sor. Two-stage compressors are sel-dom used for liquefied gas transfer.

APPLICATIONSBlackmer compressors may be used inmany industries and in many situa-tions. In general, most LPG applica-tions will fall into two categories:

Liquefied Gas Transfer: The compres-sor is used to pressurize a vessel full ofliquid. This pressure then pushes theliquid to another vessel. The mostcommon application of this techniqueis the unloading of LPG rail cars intostationary storage vessels. If needed,a compressor can also be used forgeneral liquid transfer in the plant,such as storage tank to transport orstorage tank to bulk truck or from atransport or bulk truck back to storage.After the liquid has been pushed outof the vessel, a vapor recovery opera-tion is often performed.

Vapor Recovery: Gases that were pre-viously left in the vessel or vented tothe atmosphere are now being recov-ered due to growing environmental,

safety or economic considerations.Almost any gas should now be recov-ered if at all possible. Some typicalexamples would be liquefied gasvapors left in a vessel after the liquidhas been pushed out, emptying ofvessels prior to a maintenance orrefurbishment operations, and evacua-tion of cylinders, hoses, and lines.

GENERALBlackmer compressors are quite spe-cialized among the many types ofcompressors offered in the market.They are a positive displacement, ver-tical, reciprocating design and areavailable in single or two-stage mod-els. All models have two cylindersand some are available with either air-cooling or water-cooling. Most mod-els have single-acting cylinders,although the largest have double-act-ing cylinders. Oil-free ductile ironcylinders with Teflon piston rings arestandard.

In general, Blackmer compressors maybe used on those applications withpressures in the range of 3 - 615 psia(0.2 - 42.4 bar) and 2 - 50 BHP (1.5 -37 KW). Liquefied gas transfer com-pressors are available for transfer ratesof approximately 40 - 675 GPM (9 -153 m3/hr).

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mally used openings into the tank con-nect to the liquid section in the tank.In any of these situations, a liquidpump would be useless in trying toempty the vessel. Compressors, onthe other hand, can easily handle all ofthese situations while the very bestthat a pump can do is to empty a ves-sel of liquid but would still leave it fullof vapor.

While pumps must be provided withproperly designed suction lines, thismay be impossible to do with manyvessels. A compressor is not subjectto these limitations. A compressorcan recover both the liquid and thevapor from virtually any vessel undervirtually any situation.

Figure 3 shows a typical LPG liquidtransfer system with a compressor. Inthis case, the compressor with its four-way valve transfers the contents of therail tank car into the storage tank.Note that a vapor line connects thetop of the storage tank through thefour-way valve in the compressor sys-tem to the top of the rail tank car.Also, note the liquid withdrawal linewith a dip tube connecting the top ofthe tank car to the bottom of the stor-age tank. As illustrated, a typical LPGcompressor unit is mounted on a

Figure 3baseplate complete with motor andbelt guard. Also, shown are a four-way valve, an inlet strainer, liquid trapand the discharge relief valve.Virtually every compressor used forLPG transfer will have these items.

In order to transfer the liquid from therailcar to the storage tank, the com-pressor will draw vapors from the stor-age tank vapor portion and into thecompressor where they are com-pressed slightly.

These compressed vapors, which areat a slightly elevated pressure, will bedischarged into the top of the rail tankcar. This action of pulling vapors fromthe storage tank, compressing themslightly and then putting them into thetop of the rail tank car, will slightlyreduce the pressure in the storagetank while raising the pressure in therail tank car. This difference in pres-sure will then cause the liquid to movethrough the liquid line from the railcarover to the storage tank.

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LPG TRANSFERA liquid pump cannot completelyempty a LPG vessel of all its' product.A small amount of liquid (the “liquidheel”) will always remain. Even if allof the liquid could be pumped out, thevessel would still be full of vapor atvapor pressure. This remaining vaporcan equal approximately 3% of thetank's total capacity. This means, thatif a plant were to receive its productvia transport, 97 transports unloadedwith a compressor would be the sameamount of product as 100 transportsunloaded with a liquid pump. Also, ifa vessel needs to be opened to atmos-phere for service or repair work, vent-ing the vapor to atmosphere can beexpensive and may pose a safety haz-ard. Using a compressor to recoverthese vapors before opening the tankto atmosphere can minimize both ofthese problems.

Many vessels only have openings ontop of the tank and none on the bot-tom of the tank. The most commonexample is an LPG rail tank car. If youwill recall from the pump section, allof the suggestions for a proper pipingsystem show the inlet line coming outof the tank bottom. Trying to pumpout of a tank with only top openingwill result in poor pump suction condi-tions. This will result in very shortvane and seal life and noisy operation.Also, as the liquid level lowers duringtransfer, the pump suction conditionscontinually worsen until the pump canno longer function. Considerable liq-uid will be left in the vessel anddepending upon the installation, thismight be 20 or 30 percent of the ves-sel's capacity.

Some vessels have no openings at allinto the liquid section of the tank.Typical home delivery tanks of under500 gallons (2,000 liters) and typicalsmall cylinders, such as the 20 pound(5 kg) cylinders, only have a singleopening in the top of the vessel. Also,trucks or railcars that have beeninvolved in accidents may be laying ontheir side such that none of the nor-

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COMPRESSOR COMPONENTSFigure 5 is a cross-section of a typicalLPG compressor. All the pressurecontaining components are ductileiron. The piston rod seals in the pack-ing box are a series of Teflon V-ringsthat are spring-loaded. The entire sealassembly is contained in the packingbox so that the entire packing assem-bly may be installed easily. The pis-tons are a simple one-piece design,fabricated from either steel or ductileiron. The piston rings are Teflon,which allows them to operate withoutlubrication. Both the suction and dis-charge valves are designed for non-lubricating service. The suction valvesare normally fitted with a liquid reliefdevice. This device will help to pro-tect the compressor in the event thatsome liquid does enter the compres-sor. Figure 5

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VAPOR RECOVERYOnce all of the liquid is pushed out ofthe railcar, the transfer operation canthen continue to recover the remain-ing vapor in the railcar. Figure 4 illus-trates the same installation as shownin the liquid transfer operation, exceptthat some of the valve settings havebeen changed in order to perform thevapor recovery operation. First, thefour-way valve has been rotated 90°so that the compressor will now drawvapor from the railcar and discharge itinto the storage tank, which is just theopposite of what it was on the liquidtransfer operation. Second, the dis-charge of the compressor is now rout-ed back to the storage tank's liquidportion. This will help prevent exces-sive pressure rise in the storage tank.Third, the liquid line valve is closed.

With the valves properly set, the com-pressor can withdraw vapor from thetop of the railcar, compress themslightly and discharge them into theliquid section of the storage tank. Theliquid in the storage tank will thencondense these vapors back to liquid.In this operation the railcar pressurewill gradually drop, while the storagetank pressure will rise only slightly.This operation should continue untilthe pressure in the railcar is at about

Figure 4

25-30 percent of the original tank carpressure. Of course, this pressure isgoing to vary throughout the year andwith the actual product being trans-ferred, whether it's propane or butane,because the vapor pressure of theproduct varies throughout the year.Attempting to go beyond the 25 to 30percent cutoff point is generally noteconomical since the time and energyinvolved versus the amount of productrecovered makes it not worthwhile.

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FOUR-WAY VALVEOne advantage of using a compressor is that both the liquid and the vapor may be recovered from the vessel. The four-way valve makes this process both practical and easy. The four-way valve reverses the flow of gas through the systemwithout changing the direction of compressor rotation.

Figure 7Figure 7 shows what happens inside the four-way valve. During the liquid transfer operation vapor is drawn off the top ofthe storage tank and into the top of the four-way valve where it is routed to the liquid trap and into the compressor suc-tion. The vapor is then compressed slightly and comes from the compressor discharge into the opening at the right of thefour-way valve, and is eventually routed to the railcar out the bottom of the four-way valve.

In order to perform vapor recovery, the four-way valve is rotated 90°. In this position, vapor is drawn from the railcar intothe bottom of the four-way valve and out the left side of the four-way valve to the liquid trap to the compressor suction.The compressor then discharges into the right side of the four-way valve and the gas is routed to the top of the four-wayvalve and to the storage tank.

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Figure 6

TYPICAL COMPRESSOR PACKAGESFigure 6 illustrates the various compo-nents that make up a typical LPG liq-uid transfer and vapor recovery pack-age. The mounting arrangement con-sists of the compressor, complete withpressure gauges, a baseplate, the beltguard and the belt drive system. Italso includes the four-way valve, liquidtrap, inlet strainer, relief valve and pos-sibly a liquid level switch.

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MINIMIZE LINE LOSSESWhile pipe and fitting size is not ascritical as that on a pump suction, aproperly designed system will performbetter. In general, lower pressure loss-es will require less power to drive thecompressor and will result in a fastertransfer rate. Typically, total systemlosses should be about 20-30 psi (1.5-2 bar). Pressures higher than 40 psi (3bar) should be avoided.

Installing piping or fittings that are toosmall will increase the system differen-tial pressure and will seriously degradesystem performance. In general, uselarger line sizes and keep them asshort as possible. Eliminate anyunneeded fittings, particularly on theliquid line, as this is where most of thepressure losses will occur. Use lowrestriction fittings and valves whichwill minimize pressure losses andalways ensure all strainer elements areclean.

MINIMIZE HEAT LOSSESThe compressor should always beplaced next to the vessel being emp-tied. If the compressor discharge linelength is excessive, too much heat willbe lost before reaching the vesselbeing emptied. The hot compressedgases will then start to condense. Anygas that condenses back to a liquid isessentially useless to the transferprocess and the net effect is that theoverall transfer rate will decline. Itmay be desirable to insulate dischargelines that are longer than is typical.

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LIQUID TRAPSLiquid traps are fitted to the suctionside of the compressor and must beused on all LPG compressor installa-tions. The purpose of the liquid trap isto trap liquid before it can enter thecompressor. Even though the com-pressor is connected only to vaporlines, these lines will contain some liq-uid due to changes in temperaturecausing some condensation inside theline. Also, on many systems an incor-rectly positioned valve may allow liq-uid into the vapor line.

Liquid traps provide a space for smallamounts of liquid, such as that thatwould normally occur due to conden-sation in the vapor lines to collectbefore entering the compressor. Thissmall amount of liquid will eventuallyboil off during the course of the trans-fer operation and usually poses no sig-nificant problems.

The liquid trap may be fitted with amechanical float that will physicallyblock the suction line between the trapand the compressor if too much liquidcollects within the trap. Also, an elec-tric float switch may be used to actual-ly stop the compressor's motor in theevent of high liquid level in the trap.

RELIEF VALVES AND STRAINERSAll Blackmer LPG compressors mustbe fitted with a discharge pressurerelief valve. For most LPG services, arelief valve setting of 250-265 psig(17.2-18.3 bar gauge) is typical.Ensure that the proper relief valve forthe service is chosen. Valves used forLPG, propane or butane service aretypically brass. Brass valves must notbe used for anhydrous ammonia serv-ice.

Inlet strainers should normally be usedwith compressors. Clearances insidethe compressor are quite small and

any foreign material allowed into thecompressor would quickly causesevere wear and tear and expensiverepairs will be needed soon. A 30-mesh screen is generally adequate.Clean strainers regularly. Cleaning ofthe strainer is especially important onany new systems or recently recommi-sioned systems.

Figure 8

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WATCH OUT FOR LIQUIDAllowing liquid to enter a compressorcan result in an extremely expensivefailure. As mentioned earlier, a liquidtrap must always be used with a LPGcompressor system.

If the distance between the two ves-sels is longer than normal, a larger liq-uid trap should be considered. Formost installations, the optional ASMEtrap will provide sufficient volume,although in some cases, an even largervessel may be required.

Whenever possible, place the com-pressor so that it is physically a littlehigher than most of the piping used inthe system. This will cause any liquidthat does collect in the lines to drainaway from the compressor.

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INSTALLATION GUIDELINES Figure 11 shows a typical compressorinstallation. Since Blackmer compres-sors are reciprocating rather than arotating device, a proper foundationfor the compressor and support for thepiping is very important. A 8-10-inch(20-25 cm) foundation depth is recom-mended.

The compressor baseplate must bewell supported along with its entirelength and be firmly bolted to the con-crete foundation. Pipes leading to andfrom the compressor should be wellsupported as near to the compressoras feasible. Flex connectors may beused to help dampen any vibrationinduced by the compressor.

Figure 11

Figure 9

Figure 10

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Propane Pump InstallationsPumping systems on bobtail trucks, truck transports or bulk plants all contain similar components; vapor return lines,bypass piping, suction and discharge piping which can affect the liquid transfer delivery rates. Proper pump suction designis a common consideration for any propane installation and is particularly critical for motor speed pumps, undergroundpumping and cold weather pumping.

VAPOR RETURN LINEThe vapor return line from the top ofthe receiving tank to the supply tankhelps to keep the pressure up in thesupply tank and reduces the amountof boiling. Also, relieving vapor pres-sure in the receiving tank as the liquidrises in the tank equalizes pressures inboth tanks and reduces the differentialpressure across the pump.Consequently, the pump can delivermore product at the lower differentialpressures.

The effect of this vaporization can bedemonstrated on a bobtail deliverytruck by attaching the hose to the sup-ply tank and recirculating the liquid.The flow rate when recirculating isalways more than when delivering toanother tank because the pressure inthe supply tank does not drop. Theamount of flow reduction will indicatehow much vaporization has occurredin the tank and inlet line.

Vaporization in the intake line imposesa rather rigid limit on the maximumdelivery rate, when no vapor returnline is used. This limit is about 2 to 2½% of the tank's capacity per minute,

but will vary somewhat with tempera-tures of liquid and atmosphere and intake line restrictions. For example, a1,000 gallon (3,785 liter) tank will belimited to 25 gpm (95 lpm), maximumwithdrawal rate. Overspeeding thepump or using a larger pump willhave little or no effect, once thisbarrier has been reached.

Quite often, vapor return lines are toosmall to be effective. To check theefficiency of existing return lines,

observe the pressure gage on the sup-ply tank during a delivery. If it showsa drop of more than two or three psi,vaporization can be seriously affectingthe delivery rate. A more exact checkwould be to time the delivery rate dur-ing the first minute of pumping with astopwatch, then wait several minutesand time the rate again. The secondreading will typically be less than thefirst.

BYPASS PIPING SYSTEMAll pump installations must be fittedwith a bypass line back to the supplytank. All PD pumps deliver a fixedvolume of fluid with each revolution.Therefore, provision must be made toroute any excess flow back to the tank.

If a bypass piping system is not pres-ent, fluid will recirculate within thepump. The liquid recirculating in thepump will rapidly heat up and vapor-ize. The pump may run completelydry, greatly decreasing vane and seallife. A bypass line routed to the suc-tion line will have the same effect. Aback-to-tank bypass line extends therecirculation loop allowing the recircu-

lated liquid to cool. The back-to-tankbypass line may go either to the bot-tom of the tank, the liquid section, orthe top of the tank.

Set the bypass valve at least 25 psi(1.7 bar) lower than the pump's inter-nal relief valve setting. This will

ensure the bypass valve opens first.The pump's internal relief valve shouldopen only as a final system protectiondevice. The pump's internal reliefvalve routes discharge fluid back tothe pump inlet, which will quicklycause wear and tear on the pump ifused excessively.

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Figure 12

Figure 13

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SUCTION LINE PIPINGOne of the most important considera-tions for a proper installation is thesuction line piping. A properlydesigned suction line will minimizevapor formation by limiting the linerestrictions and by preventing vaporpocket formations. In light of the ten-dency of LPG liquid to vaporize, thedesign of the intake piping plays a crit-ical role in the efficiency of every sys-tem. The following paragraphs outlinesome good design practice for LPGsuction line installations. Adhering tothese guidelines will promote longerpump service life.

a) Inlet piping from the tank to thepump should be as short as possible.

b) The pump should always be at alower level than the tank's lowest liq-uid level.

c) For stationary applications, the stor-age tank should shield the pump andinlet piping from sun's heat. Also, thesuction lines should be painted whiteor silver to reduce the radiant heatabsorption.

d) Suction line pressure losses shouldbe less than 2 psi (0.14bar). To mini-mize pressure losses in the suctionline, use low restriction type valvesand fittings. Also, long sweep radiusells are preferred.

e) The nearest fitting or strainer shouldbe at least 10 pipe diameters from thepump inlet.

f) Check and clean the inlet strainersregularly.

g) Use eccentric reducers with the flatside up.

h) Long intake lines should be avoid-ed, even when they are so large thatthey have practically no friction loss.At night or in cold weather, the liquidwill cool. Then, as the day warms orwhen a hot sun is shining on thepipes, the cool liquid will be heated,causing some liquid to be vaporized.This vapor will decrease the pump'sflow rate and increase the noise andvibration. To minimize this problem,intake lines should be sloped upwardtoward the supply tank so vapors canflow back into the tank.

i) Avoid up-across and down pipeloops where vapors can accumulate.

13

Figure 14

Figure 15

Figure 16

Figure 17

Page 15: Blackmer Lpg Handbook 500

TEM

PER

ATU

RE

0 20% 40% 60% 80% 100%

APPROXIMATE PERCENTAGE OF PUMP CAPACITY

-29°

-18°

-7°

16°

27°

°F°C

-20°

20°

40°

60°

80°

NET POSITIVESUCTION HEADNet Positive Suction Head Required(NPSHR) is the minimum inlet pressurerequired at the pump inlet to avoidexcessive cavitation. The Net PositiveSuction Head Available (NPSHA) mustbe greater than required (NPSHR) toprevent pressure at some region inthe pump suction area from droppingbelow the liquid's vapor pressure. Ifthe inlet pressure is lower than thevapor pressure, bubbles will form inthe liquid. As the bubbles travelthrough the pumping chamber to thehigher discharge pressure region, thebubbles will collapse. The collapse ofthe vapor bubbles causes pressurespikes, resulting in noise, vibration anddamaged hardware.

In addition, the vapor bubbles reducea pump's capacity since the pumpingchamber volume is being filled with amixture of vapor and liquid. Thevapor bubbles will occupy a volumewhich under normal conditions is filledby liquid. Although PD pumps areless susceptible to vapor lock than acentrifugal pump, under severe condi-tions, PD pumps will vapor lock aswell.

NPSH becomes more of a concern incertain applications such as pumpingfrom an underground tank, coldweather pumping and running a pumpat motor speed.

All typical propane transfer applica-tions operate with some degree ofvapor in the suction line. As observedon a bobtail delivery, the pump willdeliver more flow when recirculatingto the supply tank versus delivering toa cylinder. This reduced flow rate isdue to the increased amount of vaporin the suction line during the deliveryoperation. As the supply tank liquidlevel drops, the tank pressure dropsand the liquid boils, creating vaporbubbles. The vapor bubbles travelalong the inlet piping to the pump.As the fluid trapped between thevanes rotates through the pumpingchamber, the high-pressure dischargefluid collapses the vapor bubbles. Theimplosion of the vapor bubbles createsthe noise which character-izes cavitation.

NPSH required is normally determinedwith room temperature water per theHydraulic Institute's standards.However, a typical LPG installationoperates with less NPSHA than whentesting with water. Other pump man-ufacturers, both centrifugal and PD,have reported the same findings.

These general facts have been estab-lished from years of experienceregarding PD pumps for LPG applica-tions: 1. PD pumps can handle someentrained vapors without adverseaffect to pump service life.2. A flooded inlet condition is suffi-cient head for a PD pump to operate.3. Pumps handling LPG will operatewith less NPSHA than would berequired for water.4. Even pumps with properly designedsuction piping may have a negativeNPSHA.

COLD WEATHER PUMPING As the ambient temperature and prod-uct temperature drop below 40°F(4°C), a noticeable reduction in pumpcapacity is observed. An installationlocated in a cold weather region mustconsider this capacity reduction whenselecting the proper pump size. Asshown in Figure 18, pump efficienciesare significantly lower in a cold envi-ronment.

There are several guidelines that canminimize the effects of cold weatherpumping.1. Avoid high friction fittings in theinlet such as tees, globe valves, plugvalves, angle valves, check valves andstandard port ball valves.2. Use as few fittings on the inlet pip-ing as possible.3. Use one size larger inlet pipe.4. Install the pump as far below thesource tank as possible.

5. Install the pump as close to thesource tank as possible and avoid longhorizontal runs.6. Avoid low spots in the inlet pipingwhere vapor bubbles can accumulate.7. Use a larger size pump to compen-sate for the lower efficiency at coldtemperatures.8. Keep discharge pressures as low aspossible by using vapor return lines.

14Figure 18

Page 16: Blackmer Lpg Handbook 500

Delivery Systems On Bobtail Trucks

PUMP DRIVEPumps on bobtails are commonly driv-en by the power take-off through ajackshaft connected by universal joints.

A well lubricated, splined slip joint isrecommended for the drive shaft.Also note that the PTO and pump'sshafts must always be parallel; that theuniversal yokes at the ends of the jack-shaft must be parallel and in phase,and the angularity between two adja-cent shafts must not exceed 15degrees. Failure to heed these sug-gestions will result in a "gallup" oruneven turning of the pump rotor,which will result in a premature bear-ing, shaft or seal failure. Figure 20illustrates the correct mounting of thedriveline when universal joints areused.

Hydraulic driven units are becomingmore prevalent both for safety con-cerns and for ease of truck construc-tion. Hydraulic driven units increasepump service life by eliminating theexternal loading on the pump shaft,which is inherent with a power take-off. They also provide, for more con-sistent speed control and "soft starting"of the pump.

Bobtail Trucks are trucks used for localdelivery to fill end-use tanks. Theygenerally provide a metered deliveryand have tanks of 3,000 to 5,000 gal-lons (11,000 to 19,000 liters).

15

Figure 19

Figure 20

Page 17: Blackmer Lpg Handbook 500

PUMP MOUNTINGThere are several methods of mount-ing and piping pumps on bobtails.Figures 21 and 22 show the arrange-ments most common, both of whichuse an internal tank valve with excessflow capability. An internal valve ismandatory. NFPA Pamphlet No. 58requires that liquid unloading connec-tions on tank trucks be equipped withremotely controlled internal shut-offvalves. They are either flanged to thetank as shown in Figure 21, or thread-ed as in Figure 22. The valve can beactuated in any of several ways:hydraulic, using pump discharge pres-sure or an oil hydraulic system, bycable control or pneumatic power.

Ordinarily, internal valves are ideal formaximum pump performance becauseof their low-pressure drop. However,they should be checked from time totime to make sure they open com-pletely when the pump is delivering.Testing procedures are outlined inNPGA Safety Handbook, bulletin no.148-90, titled "Internal ValveOperation and Maintenance." If theystick or do not open completely forany other reason, the restriction willcause vaporization, with a resultingloss of pump capacity and shorterpump vane and seal life.

The Flange-mounted Pump (Figure21) is the ultimate in simplicity ofmounting and has the least restrictionof flow into the pump. This style isparticularly valuable when flow rates of60 GPM (227 lpm) or more aredesired.

The Foot-Mounted Pump (Figure 22)can be mounted on a pad welded tothe tank when an internal valve with asided outlet is used. This eliminatesthe need for a flexible pipe connectorwhich is usually necessary on pumpsattached to the chassis. The foot-mounting arrangement requires theuse of flanged connectors. The inter-nal valve is equipped with a strainerwhich must be cleaned periodically.

Figure 21

Figure 22

INTERNAL VALVE WITH STRAINER

REMOTE SAFETY RELEASE

VALVE CONTROL

16

Page 18: Blackmer Lpg Handbook 500

TYPICAL BOBTAIL DISCHARGE PIPING SYSTEM

1 Flexible Connector 12 Clutch Control2 Vapor Eliminator 13 Liquid Delivery Hose3 Meter 14 Vapor Return Hose4 Differential Regulator 15 Thermometer5 Manual Shut-off Valve 16 Pressure Gage with Valve6 Bypass Valve 17 Rotary Liquid Level Gage7 Tachometer 18 Pressure Gage8 Power Take-Off Control 19 Back Check Valve9 Throttle Control 20 Excess Flow Valve10 Tank Outlet Valve Control 21 Vapor Equalizing Valve11 Hydrostatic Relief Valve 22 Filler Valve

151

Figure 23 17

Page 19: Blackmer Lpg Handbook 500

TYPICAL BOBTAIL DISCHARGE PIPING SYSTEM (Cont.)

20

6

165

2122 12

19

5

18

17

15

5

1413

11109

8

76

5432

Figure 24

Figure 25

Page 20: Blackmer Lpg Handbook 500

EXCESS-FLOW VALVESExcess-Flow Valves are still in use in the liquid unloading connections of many older trucks. Delivery rates from these oldertrucks are usually lower than from new ones because their intake piping design and excess flow valves offer significantlygreater restriction to flow.

Often these older tucks can be improved by revamping the piping system between the tank and the pump. Improvementsmight include using 3 inch (75 cm) pipe instead of 2 inch (50 cm), replacing the excess-flow valve with an internal valve(which also eliminates the need for a separate strainer) and replacing globe valves with gate or ball valves.

MEASURING PRESSURE LOSSAs explained before, probably nothingaffects the flow rate through the pip-ing system more than the intake linefriction losses. You can measure theexact pressure drop due to friction inany existing system. Simply install apressure gauge in the tapped openingon the pump intake. With the pumpnot running, the pump inlet pressureand tank pressure should be equal solong as the gauges are properly set.With the pump operating at its normalcapacity, a well-designed intake lineshould not allow more than 1 or 2 psi(0.07 to 0.14 bar) total pressure drop.A higher loss than this will have a criti-cal effect on both pump capacity andlife.

A high-pressure loss on trucksequipped with an internal valve indi-cates that the valve is not opening orthe strainer is dirty. It might also indi-cate that there are unseen restrictionsto the valve inside the tank.

THE DISCHARGE SYSTEMFigure 23 shows a typical dischargesystem for bobtail trucks with all thevarious fittings detailed in theschematic.

Discharge Piping can be smaller thanthe intake piping because pressurebuild-up by the pump to overcomefriction losses in a discharge line doesnot seriously affect the pump's capaci-ty. Generally speaking, a 1¼ inch (32cm) piping system is satisfactory forflow rates up to 30-35 GPM (132 lpm)and 1½ inch (38 cm) for flow rates upto about 50 GPM (189 lpm).

A Union should be used in the dis-charge piping next to pumps withthreaded connections.

A Flexible Connector is required byNFPA Pamphlet No. 58 in dischargepiping, which is subject to stresses.System vibrations are dampened bythe flexible connectors which reducesthe attachment loading.

A Bypass Valve piped back to thesupply tank as shown in Figure 26 isabsolutely necessary for maximumpump performance and long pumplife. The bypass line is never to bepiped back into the pump intake line.The Blackmer 2" Bypass Valve (BV 2w/ Companion Flanges) is recom-mended for use on bobtails to easepiping installation and maintenance aswell as increase pump service life.

Though all Blackmer pumps are builtwith an internal relief valve, theseinternal relief valves are for emergencyprotection only and must not be usedfor normal recirculation. If a bypassvalve stuck shut or a manual bypassline valve is inadvertently closed, thepump's internal relief valve preventssystem overpressurization. Sometimesit is difficult to determine whether liq-uid is bypassing back through the sep-arate back-to-tank line or recirculatingthrough the pump's internal reliefvalve. A sight glass in the bypass lineas shown in Figure 26 are helpful indetermining bypass flow when adjust-ing the bypass valve setting.

FILLCONNECTION

SIGHT GLASS

BYPASS VALVE

FROM PUMP

TO METER AND DELIVERY HOSE

Figure 26

19

Page 21: Blackmer Lpg Handbook 500

To set the bypass valve, first check thepressure setting of the pump's internalrelief valve. Shut off the separatebypass line, then gradually shut offflow through the delivery line whilewatching a pressure gauge on thepump discharge. The pump's internalrelief valve setting is the peak pressurewhich shows on this gauge. (Afterrecirculation starts through the pump'sinternal relief valve, vaporization willcause the pressure to fall quickly).

Figure 27 illustrates the vapor forma-tion when fluid is recirculating throughthe pump's internal relief valve. It rapidly transforms to vapor becauseof turbulence within the valve, theheating of the liquid and the sharppressure drop between pump dis-charge and inlet. The recirculationresults in noise, vibration and exces-sive wear within the pump.Consequently, a back-to-tank bypassvalve is critical to longer, trouble-freepump operation.

Figure 27

The bypass valve must be set atleast at 25 psi (1.7 bar) less than thepeak pressure reading for thepump's internal relief valve. To dothis, open both the pump dischargeline and the bypass return line, allow-ing a few minutes of recirculation tobe sure of purging any vapors fromthe pump and lines. Then turn theadjusting screw on the separatebypass valve out far enough to be surethe valve is set lower than the pump'sinternal relief valve. Close the dis-charge line, causing liquid to return tothe supply tank through the bypassline. Finally, screw in the adjustingscrew on the bypass valve until theproper reading is shown on the pumpdischarge pressure gauge.

Caution: Never set the bypass valvefor a pressure higher than the differen-tial pressure rating of the pump orhigher than the maximum 125 psi (8.6bar) differential recommended byUnderwriters Lab.

There are several makes of bypassvalves on the market but they havewidely different pressure characteris-tics. Many tend to leak below thepressure for normal full-flow delivery,causing a loss of delivery rate. Someof them have a rising pressure,referred to as "tail", which results inhigher and higher backpressure as

flow rates increase. Often, with slightpump overspeeding, the backpressurewill crack the pump's internal reliefvalve, resulting in undesirable circula-tion through the pump valve.

Some types of bypass valve are sensi-tive to fluid debris and small particleswill tend to either stick the valve in theopen or closed position. Bypassvalves that stick closed, have poorpressure profiles or are improperly set,are the most common causes of rapidvane wear in the pump. Blackmer'sbypass valve (Figure 28) is quiet andsimple in construction, won't stick andhas ideal pressure characteristics.

Take extra care in sizing the bypassvalve and its piping. Pumps on truckswith inaccurate speed controls areoften oversped. If either the bypassline or valve is too small, liquid will beforced back through the pump's inter-nal relief valve. Use at least a 1¼ inchbypass valve and piping on a 2 inchpump and an 1½ inch valve and pip-ing on a 3 inch pump.

Here's a simple method of checkingthe efficiency of a separate bypassvalve. With the delivery hose closedand with the full discharge of thepump flowing through the bypass line,observe the pump discharge pressureas the engine is oversped a moderate

amount. The separate bypass valveand bypass line must be large enoughto take the extra flow from moderateoverspeeding without an excessivepressure rise.

It is desirable to use an automaticengine speed control, throttle stop orsome other speed-limiting device tomake sure that the pump can't be seri-ously oversped. If there is an enginetachometer, it should be marked forcorrect pump speed.

Meters should be used at capacitiesrecommended by the meter manufac-turers. Overspeeding on liquefiedgases will shorten the life of the meter.

Figure 2820

Page 22: Blackmer Lpg Handbook 500

The Vapor Return Line from the vaporeliminator should be at least as largeas the vapor opening at the top of theeliminator and should not contain anyfittings which would restrict the freeflow of vapor back into the tank. Ifthis line is too small or too long, or ifthere are too many restrictions in theline, vapor will pass through the elimi-nator and register on the meter, espe-cially when the tank is nearly empty.

A Differential Regulator (Figure 29)serves two purposes. It providesbackpressure on the meter and vaporeliminator, thus helping the eliminatordrive vapors back into the tank.

The regulator also serves as one moresafety device since it opens only whenthe pump is running. There have beenaccidents when the delivery hose waspulled off a moving truck. The differ-ential regulator blocked the flow sincethe pump was not running.

Figure 29 explains the principle of thedifferential regulator. The area abovethe diaphragm is maintained at tankpressure while the area below thediaphragm is filled with liquid at pumpdischarge pressure. When the pumpis not running, these pressures areidentical, so the spring keeps the valveclosed. But as soon as the pump isoperated, the discharge pressureincreases. This pressure build-upovercomes the force of the spring andopens the valve. However, a rupturedor leaking diaphragm in the regulatorcan restrict or completely block flow.

Hydrostatic Relief Valves must beinstalled in any section of liquidpiping that can be blocked off byclosed valves.

Figure 29

HIGHER DELIVERY RATESThere is an ever-increasing trend todeliver liquefied gas at higher andhigher rates. Newer trucks are usinglarger pumps, piping, hose and acces-sories. Older trucks can be revampedto improve delivery, usually byinstalling a larger intake line. Yetinstalling a larger pump or a largerintake line may not increase flow at all.The flow rate could be limited by thesupply tank size, restrictions in the dis-charge line or the restriction of thereceiving tanks. If the pump has beenrunning at its maximum differentialpressure rating, faster delivery withthe same pump can only be achievedthrough changes in the discharge sys-tem that will reduce the pressuredrop. In no case should the pump bemade to operate at more than its rateddifferential pressure.

The greatest restriction in a deliverysystem is most often the hose andfiller valve on the receiving tank,although newer filler valves are nowavailable which allow much greaterflow rates. Quite understandably,drivers prefer to use a smaller diame-ter, lightweight hose. But to achieve

delivery rates of 50 GPM (189 lpm) ormore, it is necessary to use at least a 1inch (25 cm) hose.

TROUBLESHOOTINGNo Product DeliveryOn trucks equipped with lever-operat-ed internal valves: when the lever ismoved to the open position, theexcess-flow valve may remain closed ifthe pressure on the pump side islower than in the tank. A leak in thepiping system will lower pressure.Also, putting the pump in gear beforeopening the valve sometimes willkeep the excess flow valve from open-ing. In which case, the driver mustwait until the pressure equalizes. Thisis accomplished by an orifice hole inthe valve, which allows the fluid toslowly bleed through the valve.Manually trying to actuate the valve tothe open position will help the situa-tion.

Low CapacityIf the pumping rate is not as fast as itshould be, the operator will usuallysuspect something is wrong with thepump. All too often, he will attemptto compensate by over-speedingwhich only causes more liquid to

bypass. Instead of boosting the deliv-ery rate, it will only damage thepump.

In a great majority of these cases, thedifficulty will be found in the system,not in the pump. Pressure gauges onthe pump inlet and discharge as wellas the bypass valve can help isolatethe problem. Based on the pressurereadings, the fittings and valves introuble section should be carefullyanalyzed.

Keep in mind, delivery rates will beslower when pumping Butane thanPropane. They will also be slowerwhen the weather is cold. As men-tioned earlier, delivery rates will beslower when pumping without a vaporreturn line than with one.

On older trucks that once enjoyedgood delivery rates, a gradual slowingcould be due to pump wear but notnecessarily. Worn pumps are usuallynoisier than new ones.

21

Page 23: Blackmer Lpg Handbook 500

To diagnose a system, install pressuregages in the inlet and outlet connec-tions on the pump. These connectionsare tapped gage holes usually foundnear or on the internal relief valve. Inorder to avoid variation, caused byboiling in the supply tank and pressurebuild-up in the receiving tank, run alltests while recirculating liquid backinto the same tank. Before starting thepump, check the difference in thereadings of the gages against the tankgage. Run the pump at normal speed.

Case A: If the pump inlet pressuredecreases more than 2-3 psi (0.14 -0.21 bar), vaporization in the line willseriously reduce delivery rate. Checkthe internal valve to see if it is openingall the way. An internal valve may notcompletely open for several reasons:insufficient equalization time, brokeninternal parts or insufficient excessflow valve sizing. An undersizedexcess flow valve will tend to closeprematurely. Also, inspect the strainerand clean it if necessary.

A Rego Flowmatic type valve requiresapproximately 20 psi (1.38 bar) differ-ential pressure to actuate. If the pumpis running too slow or the bypassvalve is stuck in the open position, thepump will not develop sufficient differ-ential pressure to activate the valve.

Case B: If pump discharge pressureonly increases slightly, the problem ismost likely related to the bypass valveor the pump.

A possible cause of low delivery is lossthrough the back-to-tank bypass line,either because the separate bypassvalve is set too low or the bypassvalve is leaking. To determine if this isthe problem, close the manual valve inthe bypass line while delivering. Ifpressure and flow rate increases, thebypass valve is at fault.

To determine the setting for thebypass valve, follow the procedureoutlined in the “Bypass Valve” discus-sion. If both the pump's internal reliefvalve and the separate bypass valveare properly set, yet you still can notfind the problem, the cause might beexcessive pump wear. While recircu-lating through the delivery hose withthe pump running at normal speed,check the pump's delivery against itscatalog rating. If it is too low, checkthe wear on the pump's moving parts,particularly the vanes.

However, if you find the separatebypass valve is set properly and alsofind that the discharge pressure whilerecirculating through the delivery hoseis just as high as the bypass valve set-ting, then there is too much restrictionin the discharge system to allow high-er flow rates.

Case C: If the pump discharge pres-sure rises substantially, the problem ismost likely downstream of the pump.Check for a damaged meter, differen-tial valve, vapor eliminator, cloggedmeter strainer or a restriction in thedischarge piping from the pump i.e. apartially closed valve.

PUMP TROUBLESHOOTING

Excess Vane WearThe life of pump vanes can vary wide-ly, depending on operating conditions.Unusually rapid vane wear is an indica-tor of poor system design, improperbypass valve adjustment, stickingbypass valve, pump overspeeding orsevere operational abuse.

A set of vanes should pump 1 to 2million gallons (3.8 to 7.6 millionliters) or more on average service. Ofcourse, a truck operated on two orthree daily shifts will subject the pumpvanes to more wear than a truck onsingle shifts.

The most frequent cause of vane wearis pump overspeeding, overpressureand running dry. Remove the pump'sinternal relief valve and examine it. Ifits surface is shiny and worn, liquidhas been recirculating through it,thereby causing excessive vane wear.

If the system lacks a strainer or hasone that is too coarse, dirt will abradethe vanes with coarse markings andleave scratches and grooves aroundthe liner.

Occasionally, a driver forgets to disen-gage the power take-off and drivesaway with the pump in gear. This is avery severe operating condition for thepump and will result in melting the

vanes. The other reason for rapid vanewear is pumping excessive vapors,usually the result of a restricted inletcaused by:

1. Inadequate pipe size.2. Too many elbows, tees and other fittings.3. Too long a suction line.4. Dirty strainer basket, too small a strainer or too fine a basket mesh.5. On lever operated internal valves, sometimes the wire from the controlknob in the meter compartment slipson the lever so that pulling the knobdoes not fully open the valve.6. On pressure-actuated internal outletvalves, dirt may cause them to stick ina partly closed position.

22

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Seal LeakageThe life of a seal is unpredictable.Most last several years, but there aremany things that can shorten its life.One cause is foreign material such astank scale, rust, welding slag or dirt.Another is running the pump dry oroverspeeding the pump resulting inoverheating the seal faces. This istough on both vanes and seals. Whena pump is de-pressurized frequently,the alternate heating and chilling caus-es deterioration of the seal o-rings.Pumps operating in cold climateshould be lubricated with low-temper-ature grease. If the lubricant comes incontact with the seals, some greasesthat freeze hard will damage the sealcomponents.

If the separate bypass is closed off, theflow is recirculated through thepump's internal relief valve. This caus-es the liquid to flash into vapor andthe seals and o-rings will overheatsince no liquid is present to cool thepump. Sometimes internal valves willmalfunction and close unnoticed dur-ing a delivery or, a tank may be com-pletely emptied without the operatornoticing it. If the pump runs dry longenough, heat will buildup and damagethe mechanical seals.

Noise and VibrationOne of the most common causes ofnoise and vibration is in the drivelinefrom the power take-off. Figure 21illustrates the proper alignment of uni-versal joints. If the pump shaft is notparallel with the power take-off shaftor if the two universal joints are out-of-phase, the pump shaft will rotatewith an irregular or jerky motion andimpart a surging pulsation to the liquidstream.

If the system suddenly develops noiseand vibration when there were nonebefore, check the following:1. Recirculation through pump's inter-nal relief valve.2. Dirty intake strainer.3. Other line restrictions such as partialclosing of outlet valve.4. Overspeeding the pump.5. Worn pump vanes.6. If pump was recently repaired,installation of liner or vanes back-wards.

23

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Delivery Systems On TransportsThe propane industry has over manyyears developed a progressive trans-portation system. In the early days,LPG was transported only in smallmetal containers, commonly referredto as cylinders or bottles. In the late1920's, railroad tank cars suitable forhauling LPG in large volumes wereintroduced. A later development wasthe highway transport which enabledgas to be consumed in substantial vol-umes in areas far removed from rail-road terminals. Around the mid1960's transports were beingequipped with their own unloadingpumps. Today, an unloading pump orcompressor (see compressor section)is standard equipment for a transport.

The economies of transport-mountedpumps become apparent when youcompare unloading times. It is notuncommon for motor-driven stationarypumps to require between 3 and 4hours to unload an 11,000 gallon(41,600 liter) transport. But a 4 inchpump mounted directly on the trans-port can do the job in 35-45 minutes.Spending less time in the plant andmore on the road not only increasesdriver and rig efficiency; it can mean asubstantial reduction in the number oftransports needed in the fleet.

When planning these higher unloadingrates, it is very important to haveproper mounting of the pump with acarefully engineered piping systemand driving mechanisms. Of equalimportance is a consideration of thepiping at the bulk plant where thetransport is to be unloaded. Smalldiameter piping will cause excessivepressure losses.

PUMP LOCATIONWhen selecting a position on the tankfor pump placement, safety should bethe first consideration. Tanks havebeen known to uncouple from a mov-ing tractor and in such cases, a pumplocated up front bears the full brunt ofthe transport's weight. Mounting thepump near or between the landinggear brackets allows some measure ofprotection. The safest location is justahead of the rear wheels

which provides some collision protec-tion. Hydraulic driven units havegiven the transport builder more flexi-bility with pump placement. Also,hydraulic driven units provide betterspeed control and eliminate potentialhazards from exposed rotating PTOshafts as well as increased pump serv-ice life.

Hydraulic drives make use of hydraulicoil to power rotating equipment.Hydraulic motor adapters provideclose-coupled connections betweenthe pump and hydraulic motor. TheHydrive cooler protects the systemduring cold start-up, allows for systemon/off control and provides both con-trolled system cooling and oil filtrationmonitoring. Also, Blackmer incorpo-rates a speed control valve for over-speed protection into every hydraulicdrive package.

Blackmer supplies all the major com-ponents required for a completehydraulic drive system. A typicalpackaged drive system includes a PTO,hydraulic pump, Hydrive cooler/con-troller, speed control valve, hydraulicmotor and mounting hardware.Hydraulic motor adapter kits are alsoavailable to easily mount on Blackmerpumps.

PUMP AND VALVE OPERATIONThe 4 inch flange-mounted transportpump (Figure 30) requires an internalvalve. Two valve types are typical.One is a lever-operated internal valvewith excess flow protection as manu-factured by Fisher. The other is theRego Flowmatic valve which is pres-sure-operated and remains closed untilopened by differential pressure. It isusually necessary to start the pumpwith the discharge closed to actuatethe Rego valve. In winter, the receiv-ing tank is sometimes colder than thetransport. In which case, the pumpdischarge pressure may be lower thanthe inlet. Consequently, the pressure-operated valve will remain closed.Under these conditions, you can eitherthrottle a manual valve on the dis-charge to build up pressure, or oper-ate the internal valve manually.

24

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PUMP AND VALVE OPERATION(Cont.)The function of an excess flow valvemounted in the tank bottom is to shut-off flow in the event a pump issheared from the mounting flange.An excess flow valve will not neces-sarily close in the event of a line rup-ture downstream of the pump.Shutting off the pump or disengagingthe PTO will not prevent liquid fromflowing out of the transport. In such ascenario, the internal valve must beclosed to prevent the transport's loadfrom spilling. Recent events havebrought this limitation to light andboth NPGA and DOT are workingtoward improving the transport sys-tem's excess flow protection.

BYPASS VALVEThe internal relief valve on Blackmerpumps is there to protect the system,not for continuous recirculation duringnormal operation. When ordering anew transport, always specify that a 2"bypass valve in a back-to-tank bypassline be furnished. Though a very smalladded investment on a new truck, itwill greatly reduce pump maintenancecosts and extend pump-operating life.This is particularly important if thetransport will be delivering to plantswith long or restrictive piping.

AUXILLARY INLET

STRAINER

BYPASS VALVE

DELIVERY HOSE

LOADING CONNECTION(or vapor return line)

NOTE: The back-to-tank bypassis normally piped to a seperateconnection on new trucks, thearrangement shown above sug-gests a method for adding thebypass to older transports

PUMP DRIVERefer to Figure 31 and follow these simple rules to avoid problems when usingjackshafts and universal joints to drive the pump from the power takeoff:

1. Always use the least practical number of jackshafts.2. Use an even number of universal joints.3. The pump shaft and every other jackshaft must be parallel to the PTO shaftboth vertically and horizontally.4. The remaining jackshafts do not have to be parallel with anything but theyshould not exceed 15 degrees of angularity at any joint.5. If a U-joint is used to couple two shafts with no angularity, ignore its pres-ence; consider the two shafts as one and omit the joint from Rule No. 2.6. To keep the driveline in proper alignment and balance, the tractor shouldalways be lined up with the tank while unloading.

If a transport has no bypass and it isimpractical to add one, the operatormust be instructed to operate thepump slow enough so the pump'sinternal relief valve will not open.Liquid recirculation through thepump's internal relief valve usuallymakes a noticeable noise.

Figure 30

25

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PUMP DRIVE (Cont.)Always remember that an improperdriveline will cause the pump to "gal-lop" or turn with an uneven, jerky rota-tion. This will impart a surging pulsa-tion of liquid through the piping andhose, causing the entire system tovibrate. Failure to heed these sugges-tions will result in premature bearing,shaft or seal failures.

A 4 inch Blackmer pump needs about150 ft-lbs (203 N-m) of torque todevelop a 75 psi (5.2 bar) differentialpressure. Since most popular PTOmodels are rated at 150 ft-lbs. (203 N-m), design unloading systems whichwill not require more than 75 psi (5.2bar) differential pressure on the pump.For overall performance, includingfaster delivery rates, the piping at thebulk plant should be designed so thatdifferential pressures can be kept toless than 75 psi (5.2 bar) for transportunloading.

SALT CORROSIONSalt water can seep into the propanefrom poorly serviced calcium chloridedehydrators or underground storagedomes. LPG pumps were neverdesigned to pump brine. They havelittle corrosion resistance. If the slight-est trace of salt water corrosion turnsup on pumps or other system equip-ment, investigate at once. Find thesource of the brine and correct itimmediately. Then clean out the com-plete pumping system and repair anydamage. Obviously, an extremelydangerous condition would exist if forexample, relief valves should freeze upfrom this salt water corrosion.

Figure 31

26

Page 28: Blackmer Lpg Handbook 500

Stationary Motor-Driven PumpsMotor-driven pumps are used for avariety of services from unloadingtransports to filling bottles and dis-pensing fuel to motor vehicles. Ingeneral, everything that has been saidon preceding pages about bobtail andtransport trucks applies to stationarypumps as well.

There is one important rule. Keep thepump as close as possible to the sup-ply tank. It is difficult to locate a sta-tionary pump as close to the supplytank as a truck pump. For that reason,larger intake lines should be used tohelp reduce friction. Figure 32 showsthe piping arrangement for a typicalbulk plant, using a single pump toboth deliver to and from the tank.

Where the stationary pump is onlyneeded to unload the tank, a flange-mounted pump arrangement such asthe one shown in Figure 33 hasbecome increasingly popular. Bymounting directly to the tank's internalvalve, the intake line and virtually allvaporization problems usually associat-ed with the intake line are eliminated.Loading of the tank can be done, ifnecessary, through the pump's auxil-iary intake port, using either a separatestationary pump or the transport-mounted pump.

When unloading transports, it isimportant to use the largest practicalsize of hose, or multiple hoses.

BYPASS LINE

VAPOR RETURN LINE

TO LOAD TANK VEHICLES

TO UNLOAD TANK VEHICLES

Figure 33

BYPASS VALVE

DELIVERY

Figure 32

27

Page 29: Blackmer Lpg Handbook 500

BOTTLE FILLINGCylinders or bottles are usually filledby weight. Scales with automatic trip-valves, such as those shown in Figure34, are widely used for this service.When selecting pumps for filling bot-tles, use this rule of thumb; it takesabout 1½ minutes to fill a 100-pound(45 kg) cylinder at 85 psi (5.9 bar) dif-ferential pressure. To fill one bottle ata time, a motor-mounted pumpshould do the job. For larger opera-tions, the pump size depends on thenumber of bottles to be filled at anyone time. One man can handle threefilling points by moving from one scaleto another in turn. A 2 inch, 50 GPM(189 lpm) pump has proven mostpopular for a three-station setup.

Figure 35 shows a frequently usedarrangement for a Blackmer dispensingpump involved in single-cylinder fillingsuch as motor fueling. Because thismotor-mounted Blackmer pump has acombination bypass and internal reliefvalve, the bypass line is piped directlyfrom a port on top of the pump. Abypass line size of at least ½ inch(1.25 cm) is recommended for thistype of pump, since smaller lines areexcessively restrictive to flow.

Figure 34

Figure 35

28

BYPASS LINE

Page 30: Blackmer Lpg Handbook 500

Vaporizer/Standby Plant ApplicationsCommercial or industrial users of natu-ral gas often require a standby plant asa secondary energy source. Whenquantities of natural gas are limited,these customers may have their regu-lar supply curtailed or cut off duringpeak seasons, or they may pay a pre-mium price when their usage goesbeyond a pre-determined level.

An LP-gas standby plant is the answerto both situations. It can provide asource of fuel compatible to naturalgas whenever the existing service isinterrupted, or it may function as apeak-shaving plant to supplement nor-mal supplies and reduce the cost ofnatural gas during periods of highdemand.

COMPONENTS OF A STANDBY PLANTIn addition to a liquid supply andvapor surge tank, a standby plantincludes the following equipment cate-gories: vaporizers, mixers, pumps,piping and valves.

VaporizersCommercial applications using largesize burners such as grain dryers,tobacco dryers or industrial furnacesrequire large quantities of vapor.Vaporizers employ heat to acceleratethe normal vaporization rate and areused to meet this high demand.

Vaporizers are made in a wide rangeof sizes and are usually rated in BTUper hour or in gallons-per-hour, andthis usually indicates average flowrates of liquid propane required tosupply them. These rates can varyfrom less than one to several hundredgallons per minute. Some models aredirect-fired by a flame in contact withthe vaporizing chamber, others mayuse a heat transfer medium such assteam or water, or electric heaters, toconvert the liquefied propane intovapor.

There are three main considerations inplanning for the use of vaporizer:1. Gallons per hour of liquid propanerequired.2. Amount of discharge pressurerequired from the vaporizer.3. Peak flow demand of the vaporizer.

Air MixersThere are two basic types of mixers.One type is known as the batch type,in which vapor under pressure isdrawn through an orifice into a ven-turi. One or two air check-valves maybe incorporated between the orificeand the venturi. The force of the gaspassing through draws air into the gastrain and the resultant mixture is dis-charged into a surge tank. This type ofsystem usually has a mixed gas dis-charge pressure of 10 psig or less, buthigher pressure may be achieved byusing compressed air.

The other type is called the modulat-ing type, in which a system of pres-sure control valves, regulating valvesand controller, modulate the air andgas pressures to achieve the desiredmix ratios.

Low pressure mixers sometimes use abooster blower to achieve the desiredmix gas pressure. Higher pressuretypes will require separate source ofcompressed air, in order to achievehigher mixed gas pressures. Bothtypes of mixers usually require a stor-age tank and a vaporizer.

PUMP & PIPING LAYOUTPump and piping layout systems,designed for standby plants, follow thesame general guidelines as for mostother LP-gas applications. In practice,one of the first considerations is tokeep the length of the intake pipingruns to a minimum, locating the pumpas close as possible to the supply tank,and keeping the number of valves, fit-tings and elbows to a minimum.

Friction losses within the system canresult in a pressure drop sufficient toallow liquefied propane or butane tovaporize. This can lead to pump cavi-tation, not only reducing pump effi-ciency but also creating undue wear.A simplified piping system layout canavoid these problems.

Oversized inlet piping, at least onesize larger than the pump inlet, with ashort run will minimize friction losses.Also, the pump speed should be suchthat the resulting suction line velocityis approximately 3 ft/sec (0.9 m/sec).Studies have shown the optimum inletvelocity is in the range of 160-200fpm (49 - 61 m/min). This is thespeed range which minimizes bothheat transfer and friction losses.

29

Page 31: Blackmer Lpg Handbook 500

PUMP SELECTIONBecause of the critical function of thestandby plant in providing an uninter-rupted fuel supply, the sizing of itscomponents should be governed bythe maximum peak demand of thesystem at the coldest temperature,even though the standby plant willnormally operate at somewhat lessthan this demand.

Most vaporizer manufacturers makegeneral recommendations on the GPMrating of the supply pump. A com-mon rule-of-thumb is to specify apump with a flow rating 3 to 4 timesthe rating of the vaporizer.Manufacturers suggested factors mightdiffer. There are two principle factorswhich make this oversize rating neces-sary.

A vaporizer operating at full rated out-put will have its heat exchange cham-ber nearly full of liquid propane. Thisis necessary to maintain maximumcontact area between the liquid andthe heating surface. If the vapordemand is suddenly reduced to nearzero, as will happen when the usingfurnace is shut down or modulating,the liquid continues to boil.Accumulating vapor drives liquid fromthe chamber back through the pipingtoward the pump.

Renewed vapor demand requires arapid refilling of the vaporizer and thepump must have enough capacity toprovide the necessary surge in addi-tion to the normal liquid flow rate. Ifthe total flow is insufficient to maintainproper pressure at the vaporizer, auto-matic controls should shut down thesystem.

The second consideration in sizing apump for vaporizer service is therange of anticipated operating temper-atures for the system. Standby plantsusually operate in very cold weatherwhen the demand for natural gas ishighest or premium rates are in effect.As shown in Figure 18, page 14,pump efficiencies are significantlylower in a cold environment. Thisreduced efficiency is a thermodynamicproperty of the liquid propane.

RETURN LINES AND BYPASS VALVESIf the pump has been sized correctly,its capacity will be enough to supply ademand greater than the normal maxi-mum vaporizer flow, at the lowestdesign temperature. Therefore, in nor-mal operation, the excess dischargefrom the pump must be recirculatedthrough a valve and a return line backto the supply tank. This return linemust be large enough to bypass thefull pump output, plus the back-flowfrom the vaporizer.

Two types of valves are used to regu-late and maintain the system pressure;either a differential type or a constantstatic pressure type. A differentialvalve is dependent upon supply tankpressure and will require pressure-set-ting changes throughout the year tocompensate for temperature changes.A constant static pressure valve, onthe other hand, is independent of sup-ply tank pressure and once set will notvary, regardless of temperature.

30

Page 32: Blackmer Lpg Handbook 500

APPENDIX

App. A Properties of Liquefied GasesApp. B Vapor Pressure of Liquefied GasesApp. C Saturated Propane Vapor in a 10,000 Gal. TankApp. D Friction Loss in LPG HoseApp. E Friction Loss in PipeApp. F Resistance of Valves & Fittings in Equivalent Feet of PipeApp. G Other Reference Materials from Blackmer

31

Page 33: Blackmer Lpg Handbook 500

Appendix A

PROPERTIES OF LIQUEFIED GASES *English

ANHYDROUSAMMONIA PROPANE BUTANE

Formula NH3 C3H8 C4H10

Boiling Point, °F -28 -44 32Specific Gravity of Gas (Air = 1.00) 0.596 1.50 2.01Specific Gravity of Liquid (Water = 1.00) 0.616 0.504 0.582Lbs. per Gallon of Liquid at 60°F 5.14 4.20 4.81BTU per Gallon at 60°F 91,502 102,032BTU per Lb. 21,548 21,221BTU per Cu. Ft. of Vapor at 60°F 2,488 3,280Cu. Ft. of Vapor / Gal. of Liquid at 60°F 14.14 36.38 31.26Cu. Ft. of Vapor / Lb. of Liquid at 60°F 2.75 8.66 6.51Latent Heat of Vaporization at Boiling PointBTU/Gal.

3,027 773 808

Ignition Temperature in Air, °F 920-1,120 900-1,000 Maximum Flame Temperature in Air, °F 3,595 3,615Limits of Inflammability, Percentage of Gas in AirMixture: At Lower Limit --% At Upper Limit --%

2.159.60

1.558.60

Octane Number (ISO-Octane = 100) Over 100 92* Commercial quality. Figures shown in this chart represent average values.

MetricANHYDROUS

AMMONIA PROPANE BUTANE

Formula NH3 C3H8 C4H10

Boiling Point, °C -33 -42 0Specific Gravity of Gas (Air = 1.00) 0.596 1.50 2.01Specific Gravity of Liquid (Water = 1.00) 0.616 0.504 0.582Kgs. per Cubic Meter of Liquid at 15.56°C 616 504 582Kilojoule per cubic meter of Vapor at 15.56°C 92,430 121,280Kilojoule per kilogram of Vapor 49,920 49,140Kilojoule per liter at 15.56°C 25,140 28,100Cubic Meter of Vapor per liter of Liquid at15.56°C

0.105 0.271 0.235

Cubic Meter of Vapor per kilogram of Liquid at15.56°C

0.171 0.539 0.410

Latent Heat of Vaporization at Boiling Point,Kilojoule/liter

846 216 226

Ignition Temperature in Air, °C 493 - 549 482 – 538 Maximum Flame Temperature in Air, °C 1,980 2,008Limits of Inflammability, Percentage of Gas in AirMixture: At Lower Limit --% At Upper Limit --%

2.159.60

1.558.60

Octane Number (ISO-Octane = 100) Over 100 92* Commercial quality. Figures shown in this chart represent average values.

32

Page 34: Blackmer Lpg Handbook 500

Appendix B and C

33

PSIGBAR

0.07

0.14

0.21

0.28

0.41

0.55

0.69

1.38

2.07

2.76

3.45

4.14

5.52

6.90

13.79

20.69

433832272116104-1-7-12-18-23-29-34-46 °C

°F

-40

-501

-40 -20-30 -10 0 10 20 30 40 50 60 70 80 90 100 110

3

4

6

8

10

100

80

60

300

200

2

20

30

40

50

PROPANE

N. BUTANE

ANHYDROUSAMMONIA

50% PROPANE /50% N. BUTANE

TEMPERATURE

VAPO

R P

RES

SUR

E

LIQUID AMOUNT

PSIGBAR

LITERS

GALLONS

26502270189015101140760380

3.5

6.9

10.3

13.8

17.2

0

0

TAN

K PR

ESSU

RE

700600500400300200100

50

100

150

200

250

00

Appendix B

Vapor Pressure of Liquefied Gases

Appendix C

Saturated Propane Vapor in10,000 Gallon Tank

Page 35: Blackmer Lpg Handbook 500

Appendix D and E

34

1891511147638 379303 757 1136 1514 1893 3028 3785

1000800500400300200100805040302010

PSIBAR

LPM

GPM

FLOW

6.90

5.52

4.14

3.45

2.76

2.07

1.38

0.69

0.55

0.41

0.35

0.28

0.21

0.14

0.07

FRIC

TIO

N L

OS

S

1

2

3

4

5

6

8

10

20

30

40

50

60

80

100

3/4 1 1-1/4 1-1/2 2 2-1/2

3

37853028189315141136757

1000800500400300200

3793031891511147638

100805040302010

PSIBAR

GPM

LPM

FRIC

TIO

N L

OS

S

FLOW

0.07

0.14

0.21

0.28

0.35

0.41

0.55

0.69

1.38

2.07

2.76

3.45

4.14

5.52

6.90 100

80

60

50

40

30

20

10

8

6

5

4

3

2

1

3/4

3

2-1/221-1/21-1/41

4

Appendix D

FRICTION LOSS IN LPG HOSE

Hose Friction loss in psi for 100 ft. smoothbore rubber hose with inside diameters asshown, for propane. (These values willvary because of manufacturing toleranceson hose diameters.)

For Butane ---Multiply friction loss values by 1.15

For Anhydrous Ammonia ---Multiply friction loss values by 1.21

Appendix E

FRICTION LOSS IN PIPE

Pipe Friction loss in psi for 100 ft. new,clean extra strong schedule 80 pipe forpropane

For Butane ---Multiply friction loss values by 1.15

For Anhydrous Ammonia ---Multiply friction loss values by 1.21

Page 36: Blackmer Lpg Handbook 500

Appendix F and G

35

RESISTANCE OF VALVES & FITTINGS IN EQUIVALENTFEET OF PIPE

PIPE SIZE1 1 ¼ 1 ½ 2 2 ½ 3 4

Elbow 90° 4 4.5 5 6 8 9 11Elbow 45° 1 2 2 2.5 3 4 5Tee thru side 6 8 9 12 14 17 22Y strainer same size aspipe

25 25 25 42 42 42 60

Y strainer next size larger 16 16 16 16 14 20Globe valve 28 35 45 60 65 85 120Angle valve 15 19 22 28 35 42 57Ball valve ½ ½ ½ ½ ½ ½ ½Quick-closing gate 3 3 3 3 3 3 3Above values are approximate and will vary from one manufacturer to another.

OTHER REFERENCE MATERIALS FROM BLACKMER

500-002 Application Guide - Pumping from Underground TanksCB254 LPG Equipment Training ManualCB047 Emptying LPG Cylinders with a CompressorCB048 Liquefied Gas Transfer with a CompressorCB184 Frequently Asked Questions About LPG Transfer CompressorsLBLTRAN Computer Program for LPG / NH3 Transfer CompressorsCB197 Unloading Multiple Rail CarsCB296 Transfer LPG From Underground Tanks With a Compressor / Pump

Combination --- LGL Pump Maintenance, Powerpoint Presentation--- Compressor Disassembly, Powerpoint Presentations

Page 37: Blackmer Lpg Handbook 500

NOTES

Page 38: Blackmer Lpg Handbook 500

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