* GB784763 (A)

Description: GB784763 (A) ? 1957-10-16

Improvements in temperature measuring apparatus

Description of GB784763 (A)

COMPLETE SPECIFICATION Improvements in Temperature Measuring Apparatus. We, THE FOXBORO COMPANY, a corporation organized. and existing under the laws of the Commonwealth of Massachusetts, having a place of business at Neponset Avenue, Foxboro, Massachusetts, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to gas-filled temperature measuring systems, and particularly to a pressure-responsive element, and method of making the same, used in such a system. Gas-filled pressure-type thermometers operating on the principle of Charles' Law, i.e., those thermometers referred to by the industry generally as " Class III Systems", have been in use for some time, particularly where there is a wide range of temperature fluctuations and where linear characteristics are especially desired. Such thermometers typically comprise a hermetically sealed system including a thermometer bulb, for immersion in a medium whose temperature is to be measured, which is connected through capillary tubing to a pressureresponsive element such as a Bourdon tube, etc.. The entire system is filled with an inert gas under pressure, for example several hundred pounds per square inch at room temperature, and the movable portion of the pressure-responsive element is connected to, or otherwise associated with, some type of motion or force measuring mechanism which translates the system pressure into a temperature reading. In operation, when the temperature of the bulb changes there will be a corresponding change in the pressure of the thermometer system, due to

the essentially fixed relationship, in a gas, between its temperature and pressure. The pressure-sensitive element will sense this pressure change and, if the system is properly calibrated, will provide an indication of the magnitude of the new temperature by means of the associated measuring mechanism. Even though such thermometers have been found to be suitable for certain applications, there have been a number of long-standing limitations which have prevented them from being broadly useful. For example, the relationship between the pressure of the system and the- temperature of the bulb is normally not strictly linear, as in the ideal case This is partly because the pressure responsive element and most, if not all, of the capillary tubing is out of contact with the medium whose temperature is being measured, and hence the temperature of the gas in the latter portions of the system will not ordinarily change with changes in the temperature of the bulb. This non-linearity must generally be accounted for in some manner, and various attempts have been made to do this by means of special compensation arrangements. Further, it is apparent that any change in the ambient temperature around the capillary tubing or the pressure-responsive element will alter the pressure within the system and so give an erroneous indication of change in the measured temperature of the thermometer bulb. -Any such change in ambient temperature will also generally affect the accuracy of whatever compensation is provided for the non-linear effects referred to above. Consequently, it can be seen that there are several factors leading to inaccuracy of the gas-filled type of thermometer, and that these factors result essentially from the necessity of having a portion of the gas, in the system, out of contact with the medium whose temperature is to be measured. These errors can be minimized, in a practical sense, by employing a bulb of very large volumetric capacity; however, this solution has not been broadly satisfactory, primarily because the bulb size limits its usefulness to applications where there is considerable space available. Various ambient-temperature compensators'have been suggested from time to time, but these also have been unsatisfactory, partly because their operability is restricted to a narrow range of ambient temperatures. Attempts have also been made to use various types of pressure-responsive elements, e.g. diaphragms, etc., but, for a number of reasons, none of these has provided a suitable solution to the problems. Accordingly, it is an object of this invention to provide a gas-filled thermometer which has broad utility, and which can be used in

spatially restricted applications without deterioration of measurement accuracy. It is a further object of this invention to provide a pressure-responsive element, for use with a gas-filled thermometer, which is superior to prior arrangements, and which affords high measurement accuracy and simplicity of construction. It is still a further object of this invention to provide a simple yet precise method offorming such a pressureresponsive element. According to the invention, temperature measuring apparatus includes a thermometer bulb arranged for immersion in a medium whose temperature is to be measured, capillary tubing connected at one end to the thermometer bulb, a pressure responsive bellows connected to the other end of the capillary tubing, a filler plug positioned within the bellows to reduce the volume thereof, the bulb, tubing and bellows being hermetically sealed and filled with gas under pressure, the folds of the bellows having an mternal spacing of between two and three thousandths of an inch, the external spacing between adjacent folds of the bellows being between four and six thousandths of an inch, whereby the volume of gas in the bellows is minimized so as to reduce errors in temperature measurement resulting from changes in ambient temperature around the bellows, and position-sensitive means associated with said bellows for producing a signal indicative of the expansion or contraction thereof in response to pressure variations caused by changes in the temperature of the bulb. The thermometer bellows unit so formed is believed to be arranged in such a manner as to provide minimum gas volume (and hence minimum measurement error) consistent with superior operating characteristics when used in such a temperature-responsive system. A preferred embodiment of the invention will be described with reference to the accompanying drawings, in which: Figure 1 is an elevation, partly in section, of a transmitter for producing a pneumatic signal in accordance with temperature; Figure 2 is a section (greatly enlarged) of a pressure-responsive bellows used with the apparatus of Figure 1; Figure 3 is a detail, to scale, of a portion of the bellows of Figure 2; Figure 4 is a vertical section of apparatus for forming the bellows of Figure 2 Figure 5 shows the apparatus of Figure 4 with the bellows fully formed; and Figure 6 is a plan of one of the split rings used in the apparatus of Figure 4; Referring now to Figure 1, which shows apparatus often generally referred to as a "temperature transmitter", in the upper right hand

corner thereof is a thermometer bulb 10 arranged to be immersed in a liquid or other medium whose temperature is to be measured. This bulb is of relatively small size, so that it may be inserted into siratally restricted areas, and for example may have a length of 3 inches, a diameter of -8 of an inch, and a total interior volume -of approximately 0.21 cubic inches. Connected to one end of this bulb 10 is a capillary tube 12, having an extremely small inside diameter, which leads through suitable fittings to the interior of a thermometer bellows 14 within a cylindrical capsule generally indicated at 16. The far right-hand fold of this bellows -14 seats against an inner shoulder 18 within the capsule 16, and hence does not move with changes in pressure within the bellows. The left-hand end of the bellows is formed with a cylindrical cap 20, extending through a hole in the capsule wall, and this cap is provided with a tip 22 of reduced diameter that extends into a bore in a fitting 24 threadedly engaged with the lower arm of a force bar 26. A bolt 28 is threaded into the tip 22 to firmly press the cap 20 against the force bar 26, and the fitting 24 is locked in place by a nut 30. If the temperature of the bulb 10 increases, the pressure in the bellows 14 increases and tends to move the lower arm of the force bar 26 to the left. The force bar is pivotally mounted on a pair of cross-flexures generally indicated at 32, and hence this motion causes the force bar to rock clockwise about the pivotal support. The upper arm of the force bar 26- is provided with a small plate 34 adjacent to the mouth of a nozzle 36 which is connected through passages in the interior the transmitter frame and a line restrictor (i.e.. a pneumatic resistance) to a source of gas under pressure (not shown). As the plate 34 approaches the nozzle 36. the flow of air therethrough is reduced; hence, the pressure drop across the line restrictor is reduced and the pressure in the nozzle is correspondingly increased. The nozzle 36 is also coupled through passages in the interior of the transmitter frame and through a pneumatic relay 38 (which may be of any type having suitable response characteristics, e.g., a relay such as shown in the specification of British Patent Application No. 15275/54 (Serial No.749,498) to a feedback bellows 40 which is mounted between an upstanding member 42 of-the transmitter frame and the upper arm of the force bar 26. Thus,. 'as the nozzle-pressure increases with clockwise motion of the force bar, the pressure in - the feedback' bellow correspondingly increases until the change in feedback torque exactly balances the change in torque produced by the thermometer bellows 14. The pressure in the feedback bellows is, therefore, a measure of the temperature of the bulb 10, and-this pressure is coupled through interior passages in the frame to

an- output conduit 44 for-transmission to remote indicating, recording or control equipment. Referring now to Figure 2; the thermometer bellows 14 is provided with a filler plug 50 which occupies substantially all of the interior space of the bellows (except between the folds) and thereby reduces the volume of gas in the thermometer system that is subject to ambient temperature changes. In accordance with one aspect of the present invention, it has been discovered that there is an optimum bellows configuration which provides minimum gas volume, yet affords superior operational characteristics - when used with a temperature- measuring system such as described above. For example, referring now to Figure 3, it has been found that the internal wall spacing 52, of a bellows constructed of typical material such as brass or bronze, should be between two and three thousandths of an inch. Correspondingly, the external spacing 54 between the convolution walls should be between four and six thousandths- of an inch. Such dimensional ranges avoid contact between adjacent folds, and consequent hysteresis effects, throughout the normal range of bellows pressures encountered in Class III temperature measuring systems, yet permit a -large - number of convolutions per inch axially of the bellows so as to decrease the bellows spring rate and reduce total space requirements. Advantageously, the walls of the folds are substantially parallel, except at the inner and- outer ends where the bends should be essentially unifotm and gradual, especially to ensure that the operation is linear and consistent. With such a bellows, a desirably minimum spring rate can be achieved, yet with adequate pressure capacity, with a wall thickness 56 between three and four thousandths of an inch. A highly satisfactory bellows of this type may be formed with an outer fold diameter' between 0.30-0.35", and an inner fold diameter, (i.e. " root diameter,') between 0.20-0.25". The axial length of such a bellows preferably is between 0.25-0.30"and has about 18 to 22 folds. Such a bellows provides extremely low internal volume, minimum spring rate, adequate high pressure capacity, and essentially no hysteresis or other non-linearity effects. Reverting now 0 Figure 1, the bellows capsule: 16 is positioned within a bore passing through a web 60 which is part of the transmitter frame. The capsule is formed with a shoulder ring 62 which is pressed against the right-hand surface of the web 60, and is firmly secured thereto by a plate 64 bolted to the web. The reduced-diameter stem 66 of the capsule 16 extends through a hole in the centre of the plate 64, and is coupled at its right-hand end to the capillary 12.

The transmitter is also provided with a compensation bellows 70, secured at one end to the frame member 42 and at its other end to the force bar 26. This bellows 70 is slightly pressurized, and serves in the usual way to counterbalance pressure changes in the thermometer bellows 14 that result from changes- in ambient temperature. Seated against the right-hand side of the force beam upper arm is a bias spring 72 which tends to balance out the torque produced by the thermometer bellows 14 (the internal pressure of which may be upwards of several hundred pounds per square inch). This spring 72 extends to the right, through the frame member 42, and is seated at its far end against the bottom of a cylindrical cup 74. Threadedly engaged with the cup 74 is an adjustment bolt 76 which extends back through the frame member 42 and through a hole in the force bar 26 to a cross-plate 78. This cross-plate is fastened at each end (front and rear) to a post 80 extending out from the frame member 42, to form a yoke surrounding the force bar 26 but permitting free movement thereof. Adjustment of the bolt 76 varies the position of the cup 74 as well as the tensioning of the spring-72, and thereby controls the temperature at which the force bar 26 first starts to move toward the nozzle 36 A bellows like that mentioned above with reference to Figure 3 may advantageously be formed by a crushing operation in a manner now to be described. Figure 4 shows a press adapted to perform such an operation, and which includes a circular, stepped base portion 100 having a cylindrical housing 102 seated on its outer and lowest step 104. This housing serves to guide the reciprocating movement of a piston 106 slidable therein. A previously formed bellows 108 e.g. constructed of brass or bronze and of standard commercial configuration with an outer fold diameter of about 0.32 inches and a root diameter of about 0.22 inches, is mounted on the stepped base 100 with the neck portion 110 of the bellows engaging the vertical surface of the third step 112, and the lower edge of the neck portion extending down toward the flat horizontal surface of the second step 114. Surrounding the innermost step 116, which is in the form of a boss, and pressed against the horizontal surface of the second step 112, is a circular 0being 118, for example formed of rubber or the like. The outer edge of this O-ring is in contact with the bellows neck portion 110, and serves to hermetically seal the interior of the bellows 108 from the outside atmosphere. Positioned between adjacent folds. of the bellows 108 is a series of annular spacer rings 120 which extend inwardly nearly to the root of each fold, and which are formed with smooth and parallel horizontal

surfaces. These rings have a thickness equal to the desired final external spacing between adjacent folds, e.g. 0.005 inches, and are split into sectional halves (120a and 120b) as shown in Figure- 6 to facilitate assembly with the bellows 108 prior to the crushing operation. Interleaved with this series of split spacer rings 120 is a second series of spacer rings 122, the inner diameter of which is slightly larger than the fold outer diameter, and-which have a thickness equal to the sum of the desired final internal fold spacing (e.g. 0.002 inches) and twice the bellows wall thickness (e.g. 0.006 inches). The lowermost fold of the bellows 108 rests on an annular base block 124, the upper flat surface of which serves, in a sense, as an anvil against which the folds are crushed as will be explained. Prior to the crushing operation, the bellows 108 is filled, by means of a pipe 126 leading from outside the circular stepped base 100 through the inner central boss 116, with gas under pressure, e.g. nitrogen at several hundred pounds per square inch. This pressure is sealed within the bellows by the O-ring 118, and provides an internal resistance to deformation during the crushing operation which assures that the final fold configuration conforms closely to the spatial arrangement of the spacer rings 120 and 122, and that the fold walls of the crushed bellows are substantially parallel. The piston 106 positioned above the bellows has an annular lower surface with a central recess into which the cap 128 of the bellows fits and which is sufficiently deep to prevent contact between the cap and - the piston. The lower annular surface of the piston is substantially flat and engages the upper wall of the top fold as the piston is moved downwardly, for - example by hydraulic pressure means not shown, As the piston 106 moves down, it crushes the fold walls together until, as shown in Figure 5, both sets of spacer rings 120 and 122 are firmly engaged with each other and are maintained in parallel relation by contact between their corresponding upper and lower planar surfaces. Since at this stage the spacer rings form, in effect, a solid mass, further pressure on the piston will not cause any additional downward motion, and the bellows walls will have been moulded into the desired configuration. Accordingly, it will be apparent that the invention disclosed herein achieves the several objects set forth above. An optimum combinaflan of the controllable bellows parameters produces minimum ambient gas volume in the thermometer system, and at the - same time affords superior operating characteristics over a wide range of temperatures

without taking a permanent set or being subject to hysteresis effects. Such a bellows is well suited for use in force-balance measuring apparatus, since its relatively low effective area avoids the need for complicated biasing arrangements, e.g. there is less normal force to be balanced out than in prior constructions employing a conventional diaphragm. The spring rate of such a bellows is low, and since it has a relatively large motion for a given pressure change, the need for mechanical amplification is minimized. Further. the disclosed method of forming such a bellows offers several marked advantages, especially in providing a process, well adapted for commercial production, that is capable of forming bellows walls with the desired close spacing yet maintaining the walls essentially parallel. What we claim is 1. Temperature measuring apparatus including a thermometer bulb arranged for immersion in a medium whose temperature is to be measured, capillary tubing connected at one end to the thermometer bulb. a pressure-responsive bellows connected to the other end of the capillary tubing. a filler plug positioned within the bellows to reduce the volume thereof, the bulb, tubing and bellows being hermetically sealed and filled with gas under pressure, the folds of the bellows having an internal spacing of between two and three thousandths of an inch, the external spacing between adjacent folds of the bellows being between four and six thousandths of an inch, whereby the volume of gas in the bellows is minimized so as to reduce errors in temperature measurement resulting from changes in ambient temperature around the bellows, and position-sensitive means associated with said bellows for producing a signal indicative of the expansion or contraction thereof in response to pressure variations caused by changes in the temperature of the bulb. 2. Apparatus according to Claim 1, in which the walls of the bellows are between three and four thousandths of an inch thick. 3. Apparatus according to Claim 1 or Claim 2, in which the side walls of the bellows folds are substantially parallel. 4. Apparatus according to any one of the preceding claims, in which the bellows has approximately twenty folds. 5 Apparatus according to any one of the preceding Claims, in which the outer diameter of each fold is between three hundred and

* GB784764 (A)

Description: GB784764 (A) ? 1957-10-16

Improvements in method for imparting durable lustrous finish effects tofabrics

Description of GB784764 (A)

PATENT SPECIFICATION 784,764 Date of Application and filing Complete Specification: Sept 22, 1955. No 27070/55. Application made in United States of America on Oct 18, 1954. {Complete Specification Published: Oct 16, 1957. Index at Acceptance:-Class 42 ( 1), A 4. International Classification:-DO 6 h. COMPLETE SPECIFICATION Improvements in method for finish effects We, JOSEPH BANCROFT & SONS Co, a corporation organised under the laws of the State of Delaware, United States of America, of Rockford, Wilmington, State of Delaware, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: - This invention relates to fabric finishing and is concerned with a novel method for imparting what may be termed a subdued or subtle luster finish effect to one or both surfaces of a textile fabric. According to the present invention there is provided a process of imparting a durable finish effect to fabric which has previously been treated with an impregnant capable of fixing finish effects imparted to the fabric by forming a thermoset resin or by reacting with the fabric, involving passing said fabric while still moist through a drum and belt or blanket type finishing machine and heating the fabric to set or react the impregnant and fix the finish effect, characterized in that the temperature of the drum and the contact pressure of the fabric are specially adjusted to impart a subdued luster finish effect to the fabric and that said fabric is thereafter heated in a separate curing device to set or react the impregnant and fix said subdued finish effect. In carrying out the invention, the fabric is fed to a carrier blanket which serves to carry the fabric to and in contact with the external

surface of a drying drum Various forms of equipment of this general kind incorporating a carrier blanket are known and used in the textile industry for purposes of effecting compressive shrinkage It is important that certain operating conditions be established within certain ranges, notably the pressure exerted by the blanket against the drying drum (which also determines the lPrice 3 s 6 d l imparting durable lustrous to fabrics pressure of engagement of the fabric with the drum surface), and the temperature of the drying drum. We have found that when observing the operating conditions referred to above and 50 by subsequently heating the fabric to set or cure the impregnant, a subtle or subdued luster finish effect is imparted to the fabric and such effect is rendered highly durable. Several embodiments of apparatus and 55 variations of the method are described more specifically hereinafter with reference to the accompanying drawings, in whichFigure 1 is a diagrammatic view illustrating one form of equipment usable in the 60 practice of the invention and further illustrating in a schematic manner the several steps of treatment contemplated according to the invention; Figure 2 is an enlarged detail view of 65 certain portions of the equipment incorporated in the embodiment of Figure 1: Figure 3 is a diagrammatic view of a second embodiment of equipment for practicing the invention; and 70 Figure 4 is a diagrammatic view of a third embodiment of equipment for practicing the invention. In connection with all three embodiments, it is mentioned that the forms of equipment 75 diagrammatically illustrated in the several figures are representative of types of equipment incorporating carrier blankets commonly used for the purpose of effecting compressive shrinkage of fabrics It is 80 possible according to the invention to concurrently effect at least some shrinkage while at the same time imparting the durable lusterized effect herein contemplated However, the preferred extent of lusterization is 85 achieved with operating conditions, adjustments, and variations of the equipment itself which will result in little, if any, compressive shrinkage; and, in accordance with another aspect of the invention, it is contemplated 90 that the fabric first be passed through the equipment under the operating conditions and adjustments effecting little, if any, shrinkage, and after curing of the fabric the fabric be passed again through the same or similar equipment under operating conditions and adjustments adapted to effect appreciable compressive shrinkage. With the foregoing in mind, reference is first made to the embodiment illustrated in Figures 1 and 2. As indicated in Figure 1, the fabric F is delivered from the supply roll 3 to a mechanism 4 adapted to apply an impregnant to the fabric, for instance, a thermosetting resin precondensate Here the fabric

picks up the resin or other impregnant, preferably in aqueous solution, and the fabric is then passed to a dryer 5 in which it is dried to a moist condition The fabric is then delivered to the carrier blanket and the associated equipment for imparting the luster, after which it passes through a curer 6 being ultimately rolled up as indicated at 7. Since the equipment here used for imparting the luster may be of a type known per se, it is not illustrated in detail herein However, it is pointed out that a typical machine of this kind includes a carrier blanket 8 traveling in a closed circuit and having a sharply curved run established by a supporting roll 9, from which the blanket passes around the periphery of a large diameter drying drum 10. The blanket is delivered from the drum over the roll 11 and then passes over a blanket drying drum 12, from which it returns over suitable guides to the supporting roll 9 For the purpose of maintaining tension in the blanket one of the guide rolls therefor, for instance one of the rolls immediately adjacent the drum 12, is adjustably mounted and preferably biased by weights, so as to tighten the blanket In this way tension is set up in the blanket and blanket pressure against the drum 10 is established. A guide 13 serves to deliver the fabric to the blanket at the start of the curved run around the blanket supporting roll 9, from which the fabric passes around the drum with the blanket 8 in a position interposed between the drum and the blanket A guide 14 provides for delivery of the fabric away from the blanket and drum, for independent travel to the fabric curer 6. In the embodiment of Figures 1 and 2 one or more pressure shoes 15 are arranged to engage the fabric as it passes with the blanket in the sharply curved run established by the roll 9 While such shoes need not necessarily be used, as will appear from the description of the embodiment of Figure 3, where the shoes are used, they are preferably arranged so that the toe of such shoe or shoes, as indicated at 16 in Figure 2, extends around the run of the blanket over the roll 9 substantially all the way to the point of delivery of the blanket (and thus of the fabric) to the exterior surface of the drum Appropriate yielding mounts for pres 70 sure shoes of the kind just mentioned are known and, therefore, need not be described in detail herein Heater elements 17 may also be provided in the pressure shoes and are preferably employed to heat the shoes 75 to a substantial temperature, say from about 300 'F to about 400 'F. We have found that by the above treatment a desirable type of subtle luster effect is imparted to one surface of the fabric, 80 provided certain conditions of temperature of the drying drum and of pressure against the drying drum be observed Thus the pressure of the blanket

against the drum should be of the order of from 3 5 ounces 85 to 3 lbs per square inch, and the drying drum temperature should be of the order of 230 'F to 300 'F The desired pressure may be established by appropriate weight of the adjustable blanket guide roll above men 90 tioned, and the desired drum temperature may be established by regulating the pressure of heating steam supplied to the drum. Some variation of the extent of lusterization may be effected by varying the pressure and 95 temperature within the limits just referred to; and the pressure and temperature selected may also vary somewhat according to the nature of the fabric and also the nature of the impregnant applied to the 100 fabric. It will be understood that the heating effect resulting from passage of the fabric in contact with the drying drum will ordinarily result in little, if any, actual 105 curing, the curing of the impregnated fabric being effected subsequently in order to fix the luster effect, as by heating in a curer or oven, in which the temperature of the fabric may be raised to from about 260 'F 110 to 400 'F for a period of about 1 minute to about 100 minutes The higher temperatures, of course, require the shorter time. Fabrics of a variety of types may be treated according to the method of the 115 present invention, including both natural and artificial cellulosic fabrics, and also fabrics made of synthetic linear polyamides or other resin type materials. The impregnant applied to the fabric may 120 either be of the thermosetting type or may be of a type adapted to react with the material of which the fabric is formed, so long as it is capable of fixing the finishing effect after delivery of the fabric from the 125 carrier blanket, for instance, by passage thereof through the oven or curer, such-as indicated at 6. The specific form of impregnation equipment employed is not here of concern, but 130 784,764 such shoes being present in Figure 1 but absent in Figure 3 The pressure shoes are frequently employed in compressive shrinkage operations and when operating in accordance with Figure 1, some compressive 70 shrinkage may occur, although, as above indicated, the adjustments of shoe pressure, fabric feed speed, drum speed, etc, are preferably such as to impart little, if any, compressive shrinkage even in the case of 75 use of such shoes, as in Figure 1 In the arrangement of Figure 3 still less tendency toward compressive shrinkage is present because of the spacing of the blanket supporting rolls 9 a and 9 b so as to leave at 80 least some free run of the blankets as they approach the surfaces of the drying drums. Turning now to the embodiment of Figure 4, there is here shown a machine of the type incorporating a carrier blanket or 85 belt 18 of substantial thickness, say of the order of 2 ", constructed, for

example, of soft rubber This blanket or belt passes over a supporting roller 19 and from there to the surface of the drying drum 20, and 90 thence over suitable rollers to complete the circuit back to the supporting roller 19 In this instance the exterior surface of the blanket or belt may be cooled as by the spray device 21 located at a point beyond 95 the point where the fabric web leaves the blanket or belt In common with the arrangement of Figure 1, the arrangement of Figure 4 also provides for the imparting of the finish effect to one surface only of the 100 fabric web. The rubber blanket or belt type of machine may be used in combination with one or more fabric type of blanket unit. such as those shown in Figures 1 and 3, 105 the fabric being passed sequentially through the rubber blanket or belt machine and then through the other units In this way modified effects as to both luster and also shrinkage are obtainable 110 As to both of the arrangements of Figures 3 and 4, it should be understood that similar conditions of blanket or belt pressure and drying drum temperature should be employed With regard to the 115 matter of pressure it is to be noted that ordinarily the type of blanket machine illustrated in Figures 1 and 3 would be operated to provide a blanket pressure against the drying drum of the order of 120 from a few ounces per square inch up to about 1 lb per square inch Where higher per square inch pressures are desired, running for example, up to about 3 lbs per square inch, these pressures may be obtained 125 by the employment of the rubber belt or blanket type of unit generally illustrated in Figure 4. Subsequent to the final curing step contemplated in accordance with all embodi 130 it is desirable that following impregnation the fabric be dried to a moist condition, for instance, to a condition containing from about 2 % to about 18 % water, as compared with the bone dry fabric Excessive moisture in the fabric delivered to the carrier blanket is to be avoided, so as to minimize transfer of impregnant to the blanket. In the embodiment illustrated in Figure 3, the fabric F is fed to a carrier blanket 8 a in the region of the supporting roller 9 a and passes thence in contact with the surface of the drying drum i O a in a manner similar to that described above with reference to Figure 1 Here, however, the shoes 15 referred to in the description of Figures 1 and 2 are not employed and the diameter of the blanket supporting roller 9 a and/or the thickness of the blanket 8 a are so selected as to provide some spacing between the blanket and the surface of the drying drum in the region where the blanket passes from the supporting roller 9 a to the drying drum 1 Oa. In the embodiment of Figure 3, after delivery of the fabric from the first drying drum ( 1 Oa), the fabric may be delivered to the blanket

8 b of a second unit incorporating drying drum 10 b The blanket supporting roller 9 b of the second unit and/or the thickness of the blanket 8 b thereof is also selected to provide the spacing from the surface of the drying drum aforementioned. It will be observed from inspection of Figure 3 that the threading path of the fabric through the two drying drum units is such as to bring one face of the fabric into contact with drying drum i O a and the opposite face of the fabric into contact with drying drum l Ob Thus the arrangement of Figure 3 provides for the imparting of the luster effect to both surfaces of the fabric. If the finish effect is desired on only one surface of the fabric, only one finishing machine of the kind shown in Figure 3 need be used. It will be understood that as in the arrangement of Figure 1, the fabric is preliminarily impregnated with the desired impregnant, partially dried, and then delivered to the first blanket-and-drum-unit, and also that following delivery of the fabric from the second blanket-and-drum-unit, the fabric is passed through a suitable curer in order to heat the impregnated and lusterized fabric and thereby fix the lusterized effect. In addition, it will also be understood that, as in the arrangement of Figure 1, the desired blanket pressure against the drums l Oa and l Ob may be established by appropriate adjustment of the blanket tension. In comparing Figures 1 and 3 it should be observed that there is a difference with respect to the use of the pressure shoes 15, 784,764 ments, the fabric may be passed through the same or a similar machine with adjustments adapted to effect compressive shrinkage. According to the foregoing, an attractive, durable, subtle or subdued luster effect may readily be applied to a fabric by the use of known and commonly available equipment. Moreover, the invention not only provides for the imparting of a durable lusterized finish but further provides for the production of such a finished fabric having good shrinkage characteristics, as by the subsequent passage of the surface finished and cured fabric through a compressive shrinkage machine, which may even be the same machine as employed to impart the luster. The method of the invention may also be applied to fabrics which have received a pressure mechanical finish treatment after the impregnation and partial drying steps. The pressure mechanical treatment mav consist of glazing, embossing, or the like, and in this event the subtle luster effect is superimposed upon the mechanical finish effect.

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* GB784765 (A)

Description: GB784765 (A) ? 1957-10-16

An improved method of and apparatus for the rapid and uniform heating ofindustrial furnaces

Description of GB784765 (A)

PATENT SPECIFICATION 784,705 Date of Application andfiling Compiete Specitifition Sept 27, 1955, No 27523155. Application made in Germany on July 19, 1955. Complete Specification Published: Oct 16, 1957. Index at Acceptance:-Classes 51 ( 1), BA 8 (A 1:B:B 5: G:K:L: M: R), BA 26; and 75 ( 1), TA 2 (A 1: B 2: D). International Classification:-F 23 c, d, f. COMPLETE SPECIFICATION An Improved Method of and Apparatus for the Rapid and Uniform Heating of Industrial Furnaces. We " OFU " OFENBAU-UNION, G M B H, of 67, Graf Adolf Strasse, Dusseldorf, Germany, a Company organised under the laws 'of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:The invention relates to an improved method of and apparatus for the rapid and uniform heating of industrial furnaces of the kind wherein the heating flames are directed along the furnace walls. When it is necessary to heat articles of high quality, e g bundles of laminations, rolls of wire, or to anneal boilers to relieve stresses, the problem arises as how to heat the articles with a minimum of damage and at the same time in an economical and time saving manner It has, therefore, been suggested that the material to be heated should

be kept during annealing as much as possible away from the direct action of the heating flames. To this end, it has been proposed to construct the heating furnaces in such a manner that the flames are directed along the furnace wall so that they do not come into direct contact with the material being heated. Heating furnaces have been built with circular or slightly conical apertures in their walls, within which are arranged burner nozzles whose outlet openings are directed parallel to the furnace wall with the-result that the heating flames are directed along the said wall The disadvantage of this known construction is that the burner nozzles are subjected to high furnace temperatures and are therefore prone to breakdowns which are expensive. According to the invention an industrial furnace for the indirect heating of material in a closed chamber wherein the heating lPrice 3 s 6 d l flames are directed over the furnace walls is characterised in that a 'burner is disposed 45 with its axis normal to the wall of the chamber and the combustible media issues from the burner as a whirling jet to the burner duct associated therewith said duct merging as a continuous curve of increasing gradient into 50 the furnace wall so that the core of t 1 d jet is of a low pressure and a reverse current of furnace gases is thereby produced, the whirling movement imparted to the combustible media and the form of the burner duct 55 stabilising the deflection of the flame and forcing it into contact with the furnace wall. The arrangement is preferably such that a number of burners are distributed over the furnace walls in staggered formation 60 According to a further constructional form of the invention a screen or wall which forms an -obstacle to the direct issue of flames and to backflow from the furnace chamber, is provided in the furnace chamber in front of 65 the mouth of the burner duct The screen or wall can also expediently be constructed as an annular disc, projecting partly into the burner duct, in which case its surface lying opposite the mouth of the burner duct is constructed 70 as curves of increasing gradient The annular disc can be suspended so as to hang free. According to a further preferred constructional form of the invention, the axis of the burner duct can deviate from the direction 75 of the burner axis in the form of any desired curve, e g with a gradient which increases towards the outlet of the burner duct. Further features of the invention will be explained in more detail with reference to 80 Figure 1 to 7 of the accompanying drawings which illustrate by way of example apparatus for carrying the method according to the invention into effect Figure 1 is a side view, partly in section, of 85 a burner arrangement suitable for carrying into

effect the method according to the invention Figure 2 is a sectional view of a second constructional example showing the details of an apparatus which is adapted to impart a rotary movement (whirling movement) to the fuel for combustion. Figure 3 is a sectional view of a part of Figure 2 taken along the line III-III. Figure 4 is a longitudinal sectional view of a third constructional example of the invention. Figure 5 is a view, partly in longitudinal section, of a fourth constructional example. Figure 6 is a longitudinal sectional view of a fifth constructional example. Figure 7 shows five cross-sections taken through the burner duct according to Figure 6. Figure 1 shows partly in section, part of the wall of an industrial furnace adapted for carrying out the method according to the invention The burner duct illustrated is conveniently duplicated and distributed in staggered formation or other arrangement over the furnace wall during its construction. The fuel for combustion, e g fuel gas, oil, powdered coal and air and hereinafter termed " fuel " is fed through connecting pipes 2 and 3, the latter supplying the necessary combustion air to a burner I in which a helical or spiral (whirling movement) is imparted to the fuel From an outlet opening 7 the fuel passes in spiral form as at 11 into a burner duct 8 bounded by a burner brick 5 The burner duct 8 is so constructed that the boundary lines of the burner brick form, in longitudinal section, curves of increasing gradient 6 which merge into the furnace wall 4 The burner brick 5 is bedded into the furnace wall 4. The curves of increasing gradient are preferably continuous, parts of ellipses and cycloids have proved advantageous, but it is also possible to employ other curves, e g. arcs of circles, parts of parabolas of any degree, parts of hyperbolas, and parts of logarithmic curves. Owing to the whirling movement transmitted to the fuel and by reason of the form of the burner duct 8 bounded by curves 6 of increasing gradient, when the flames leave the burner duct they are directed along the furnace wall so that they are not projected straight into the furnace chamber to contact directly the material under heat treatment. The effect is achieved due to the fact that fuel issuing from the burner duct with a whirling movement creates a suction effect which sets up a back flow of atmosphere from the furnace in the direction of the burner axis, such back flow being repelled in the mouth of the

burner duct. Figure 2 is a sectional view of another constructional example, showing a burner which is particularly suitable for carrying into effect the method according to the invention. This burner makes it possible to impart as constant whirl io the fuel independently of the qquantity supplied 10 The burner in Figure 2 consists of the burner housing la with the gas pipe 2 and air pipe 3 A sleeve 34 is mounted so as to be pivotable and axially displaceable -in the interior of the housing la, its front end being 75 formed as a gas nozzle with a nozzle portion 35. A rim part 37 forming the nozzle mouth is integral with a tubular part 36 arranged between the burner housing I a and the burner brick 5 80 The two oppositely disposed nozzle parts and 37 are toothed at their edges in their plane of division in the manner of a ratchet coupling The individual teeth consist of a vertical or substantially vertical front face 38 85 and a sloping tooth back 39 which is inclined at an angle with respect to the general axis of flow and constructed to provide a helical surface The front faces 38 can be radially directed, but preferably, and in this particular 90 embodiment they are arranged at a definite pitch angle in such manner that the planes of the front faces 38 lie substantially parallel to the burner axis and are tangential to a theoretical whirl circle 40 The crests and 95 valleys of the teeth can also be directed substantially perpendicularly to the burner axis without substantially impairing the effect according to the invention As in the case of a claw coupling, both the front faces 38 and 100 also the backs 39 of the teeth contact one another when in full engagement, and form a closed ring. Since the tooth backs 39, always contact one another with a sealing fit even when the 105 two nozzle parts 35, 37 are not completely engaged, the two parts can be turned relatively one to the other so as to adjust the area of the openings 55 between the faces of the teeth according to the angle of turn Through 110 these openings 55 the air flows in jets inclined with respect to the burner axis and tangentially to the whirl circle 40 and are mixed with the axially flowing gas. The sleeve 34 can be rotated by means of 115 an operating lever 41 mounted on the free end of the sleeve, and can also be moved in an axial direction A stud bolt 42 provided with nuts 43 is fixed to the housing la, and a projection 44 of the lever 41 is guided on the stud 120 bolt 42 between the nuts 43 by means of an arcuate slot in the projection 44 The nuts 43 serve at the same time for fixing the operating lever 41 in a chosen position The sleeve 34 is provided with a radial aperture 45 through 125 which the gas supplied through the pipe 2 can be fed into the burner nozzle An annular packing 46 between

the burner housing, and the sleeve 34 provides a gas-tight closure At the end of the sleeve 34 remote from the 130 184,165 relieving furnace, further modification is expedient ' Such a constructional example of the present invention for use with stress-relieving furnaces is illustrated in Figure 5, wherein it 70 is assumed, as in Figure 4, that liquid fuel is to be used. In the constructional example of Figure 5 an annular disc 60 having a central opening 61 'arranged concentrically with the burner 75 axis, is disposed in front of the burner duct. If a baffle wall arranged as a simple plate were used, the return flow Would pass into the burner duct fron the side, thus producing flow condition's in which it would still be 80 possible to a slight extent for the material being annealed to undergo the risk of small local overheating. With the use of the annular disc 60, the return flow is how introduced into the burner 85 duct through the central opening 67 according to the arrows 61 and 62 from the centre of the said disc; from here the gases are again led out from the mouth of the burner duct as shown by the arrows 63 and 64 As is shown 90 in the drawings, the gases which are aspirated from the furnace chamber, as shown by arrows 63, 64, 61 ', 62 ', wash the baffle wall on all sides It is thereby protected from being, overheated to an unallowable extent, 95 whilst at the same time it covers the zones giving the greatest heat radiation The radiation which enters the furnace through the central opening 67 in the annular disc 60 has no harmful affect since the radiation of the 100 whirling core of the flame is very slight. As is shown in Figure 5, the annular disc can project partly into the burner duct 8 and its surfaces which lie opposite the curves 6 of the burner duct 8 are expediently con 105 structed as curves of increasing gradient. The annular disc 60 can be suspended and so arranged that in one position'it enters into the burner duct so that it allows only a narrow annular gap through Which the flame can 110 issue all round the said disc When the output of the furnace increases the annular disc moves outwards in the axial direction (in the drawing: towards the right) and provides a wider annular gap through which the corm 115 bustion gases can issue. It should, however, be stressed that the aforedescribed construction of the burner duct according to the invention in itself generally guides the flame so effectively along 120 the furnace wall that in normal annealing furnaces it is only very rarely necessary to provide a baffle wall in front of the burner duct If the wall 10 (Figure 4) or disc 60 (Figure 5) is mounted so as to be inter 125 changeable or removable, it is advantageously possible to provide a multi-purpose

furnace which can be used both as an annealing furnace and also as a so-called stressrelieving furnace,',,' ' 130 g:upp 13 nozzle there is provided a' cleaning opening with closure plug 47. A third constructional example is illustrated in Figure 4 ' This apparatus is adapted to carry ihe method according to the invention into effect when a liquid fuel is being used. The liquid fuel is fed through a pipe 15 and a feed pipe 17 to an atomising cup 18. Through a stub pipe 19 having a throttle valve 20, air passes into a blower 21 and then through an annular passage 22 to the nozzle outlet and assists the atomisation of the liquid particles which are projected from the atomising cup 18 'The blower 21 is driven by a motor 16 through a hollow shaft 23 mounted in anti-friction bearings 24 Air is introduced through the pipe 3 into an annular chamber' 27, is given the desired whirling movement in an_ adjustable whirl-imparting device 25 and passes through an annular channel 26 to the nozzle outlet Here the air imparts its whirling-movement' to' the air fuel mixture'issuing from 18 and 22, so that, in co-operation with the burner duct constructed according to the invention, the flames are directed along the furnace wall. A baffle wall or screen 10 can be arranged in the furnace chamber in front of the burner duct in order to prevent the flames from acting directly on the material under heat treatment. A wall or screen 10 of this kind may be expedient if it is feared that in certain operating conditions the whirling movement of the fuel might not be sufficient to direct the flame reliably along the furnace wall, e g when -the input is reduced very considerably or when the air supply fails owing to operational faults, etc The effect of the baffle wall 10 in these cases is to protect particularly delicate material from being damaged In addition, with burner arrangements according to the invention a return flow is set up in the core of the flame so that during the heating up stage, particularly in the case of oil burners, owing to the cold state of the furnace chamber there is a danger that cold furnace gases may enter the burner through the return flow and cool down the flames so considerably as to cause incomplete combustion and thereby to endanger the material being heated. The use of a baffle wall ensures that during the heating up period only hot gases can flow back into the burner duct, so that efficient combustion can take place directly after the flame has been ignited. When the invention is used with annealing furnaces of all kinds, the invention provides completely satisfactory results when the aforesaid constructional examples are used But if the invention is to be used for the stressrelieving annealing of very delicate material at relatively low temperatures, e g 'up to approximately 600 'C in a

so-called stress784,765, z A further possible construction of the burner duct for carrying into effect the method according to the invention is shown in Figure 6. As seen in longitudinal sectional view the interior of the burner duct is again bounded by curves of increasing gradient which merge into the furnace wall, but the cross-sectional views taken through the burner duct no longer represent concentric circles, as has been hitherto assumed, but form eccentric circles (Figure 7). In the arrangement according to Figure 6, the flames travelling along the furnace wall are, above all, guided towards the upper part of the furnace Other constructions are also conceivable in which, for example, the flames are guided downwards, to the right or to the left, or in any oblique direction Likewise, the individual cross-sections of the burner duct may be, not circles as illustrated, but shaped in the manner of ellipses. The method which has been described has the advantage, as compared with known methods, that all the delicate parts of the burner are arranged some distance from the hot furnace chamber The known advantages of radiant heating by means of wall surfaces heated to a very high degree-i e very rapid heating of the material in the furnace and no direct flame action on the said material-are here combined with the advantage of a simple design which is very trouble free A further advantage is that, as the flame flows very smoothly into the furnace, as compared with known methods, even temperature is provided along the whole furnace wall, thus preventing irregular heat distribution. The method is particularly suitable for use in forging furnaces furnaces for the stressrelieving and annealing of welded constructions in order to heat material very rapidly, uniformly and without damage.

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* GB784766 (A)

Description: GB784766 (A) ? 1957-10-16

Improvements in cubicles housing drawout type switchgear

Description of GB784766 (A)

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PATENT SPECIFICATION v 784,766 Date of Application and filing Complete Specification: October 13, 1955. A t 'i i ^ l No29228/55. Application made in United States of America on October 25, 1954. 0 DY Complete Specification Published: October 16, 1957. Index at acceptance:-Class 38 ( 5), B 2 B( 9: 10: 15), 53 (A 3: K). International Classjification:-HI 01 n H 02 b. COMPLETE SPECIFICATION Improvements in Cubicles Housing Drawout Type Switchgear We, ALLIS-CHALMIRS MANUFACTURING COMPANY, a Corporation organised under the laws of the State of Delaware, United States of America, of Post Box 512, Milwaukee 1, Wisconsin, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention comprises improvements in cubicles housing drawout type switchgear. It is customary in both indoor and outdoor switchgear equipment to provide metal cubides for housing the various switchgear components, such as switches or circuit breakers and the like It is further usual to provide a panel door for each switch enclosed in a switchgear unit. When the panel door is closed, energized portions of the switch are

enclosed for the protection of operating personnel and to maintain acceptable atmospheric conditions. In some types of drawout switchgear, when equipped with a conventional door hinged at a fixed position onto the cubicle, it is necessary to open the door in order to move or withdraw the switch on its mounting to a disconnected position In the disconnected position the switch then projects beyond the door hinge making it impossible to close the door This situation is highly undesirable as the energized portions of the switchgear are then exposed and present dangerous areas to possible contact by the operating personnel. Attempted solutions of this problem have included provision for a cubicle large enough to permit withdrawal of the switch to its fullest extent without requiring opening of the panel door This solution is unsatisfactory for two reasons First space is at a premium requiring minimal sized cubicles and second, in the operating position of the switch the manual control means will be (Price spaced at a considerable distance from the door Operation of the operating portions or manual control means on the switch becomes difficult and unsafe This condition necessitates addition of linkage means be 50 tween the door and manual control means on the switch Such linkage systems have been used commercially but their application involves complications in design and in operation and maintenance Further, when it 55 becomes necessary to replace the switch by one of a rating other than the original, a complete new set of linkages may have to be designed and built to effect proper operation Accordingly, this aproach is com 60 mercially unfeasible. An object of the present invention is to overcome these disadvantages by providing a cubicle which will permit operation of the switch whilst furnishing maximum protection 65 to operating personnel. According to the present invention there is provided, in drawout switchgear, the combination comprising a cubicle housing the switchgear, a door hingedly mounted on the 70 cubicle and comprising a panel having a dished portion formed with a cutout section for receiving switchgear components, and means for selectively mounting the panel door on the cubicle with the dished portion 75 facing towards the interior of the cubicle or facing outwardly from the cubicle. Also according to the present invention there is provided in drawout switchgear, the combination comprising a cubicle housing 80 the switchgear, a door hingedly mounted on the cubicle, said door comprising a door frame and a reversible panel adapted to be mounted on the door frame, the panel having a dished portion provided with cutout 85 sections for receiving switchgear components, and means for selectively mounting the panel on the door frame so that the dished

portion faces towards the interior of the cubicle or faces outwardly from the cubicle 90 784,766 Other features of the invention will hereinafter be described and referred to in the appended claims. The invention is illustrated, by way of example in the accompanying drawings, in which:Figure 1 is a side elevational view of a switchgear cubicle embodying the invention; Figure 2 is a frontal view of the switchgear cubicle of Figure 1; Fig 3 is an enlarged fragmentary view in elevation showing the door frame mounting a reversible panel therein, Fig 4 is a view in section along line IVIV of Fig 3; Fig 5 is a view in section along line V-V of Fig 3; Fig 6 is a modification of Fig 5 showing the reversible panel dished outwardly from the switchgear; Fig 7 is an enlarged fragmentary view of a modification of means for mounting and fastening the reversible panel in the door frame; Fig 8 is a view in section along line VIII-VIII of Fig 7; Fig 9 is an enlarged view in section of the seal means carried by the cubicle, Fig 10 is a fragmentary view in elevation of a modification of the invention in which the door frame and panel are integral; and Fig 11 is a view in section along line XI-XI of Fig 10. Figs 1 and 2 of the drawings show an arrangement of low voltage switchgear The illustrated switchgear includes three circuit breakers or switches 10, 11 and 12 movably mounted in a cubicle 13 having a front 14 and a rear 15. Switches 10, 11 and 12 are movably mounted in cubicle 13 by supporting means which wholly supports an individual switch 10, 11 or 12 and permits movement of the switch relative to cubicle 13 Any known type of supporting means may be utilized to effect the required movement The present arrangement utilizes pairs of conventional pantographs 16 The pantographs 16 are pivotally attached to cubicle 13 and switches 10, 11 and 12 Accordingly, an individual switch may be moved from its normal operating position as shown by switch 10, to a disconnect position as shown by switch 11, or to a test position such as shown by switch 12, supported by pantographs 16 and moved by any suitable means for actuating the supporting means to bodily shift the switch from the energized or connect position into the test position or into the disconnect position. The means for actuating the supporting means may include any suitable known drawout structure such as screws 17 which are threaded through a portion of individual switch 10, 11 or 12 and journaled and carried by cubicle 13 Screws 17 may be rotated by a crank (not shown) which may be fitted and detachably connected to a squared portion 18 normally accessible at front 14 of individual switches 10, 11 or 12 in cubicle 13. Operation of screw 17 permits individual 70 switches 10, 11 or 12 to be bodily shifted from the energized or connect position of switch 10

into the deenergized or disconnect position of switch 11. The several positions of an individual 75 switch 10, 11 or 12 permit selective placement of primary and auxiliary contacts 21, 22 of switch 10, 11 or 12 with respect to circuit fixed primary and auxiliary contacts 23, 24 80 A schematic showing is made of the connections of primary and auxiliary contacts 21, 22 connecting individual switches 10, 11 and 12 to circuit primary contacts 23 presented by the circuit to be protected and to 85 auxiliary contacts 24, respectively The circuit primary contacts 23 are shown connected to representative three phase bus bars connecting the circuit with switches 10, 11 and 12 Circait auxiliary contacts 24 are 90 provided for the various control signals and responses necessary to operate switch 10, 11 or 12. In all positions of switch 10 11 or 12, the contacts 21 and 22 thereof are in alignment 95 with their mating contacts 23, 24 Contacts 21 and 22 are adapted to be connected to contacts 23, 24 by sliding frictional engagement therewith Switch 10 illustrates the connect position in which both primary and 100 auxiliary contacts 21, 22 23 and 24 are connected Switch I 1 illustrates the position of the switch in the disconnect position with all contacts open And switch 12 illustrates the test position wherein the primary con 105 tacts 21, 23 are disconnected, but the auxiliary contacts 22, 24 are still connected The test position permits actual operation of the control circuits of switch 10, 11 or 12. The requirement of being able to position 110 switch 10, 11 or 12 in three positions with respect to the primary and auxiliary contacts 21, 22, 23 and 24 gives rise to the present invention Each individual switch is provided with a panel door 28 mounted on 115 cubicle 13 to provide a anens of access to switch 10, 11 or 12 Panel door 28 shown in detail in Figs 3, 4, 5 and 6, includes a door frame 29 carried on cubicle 13 and a reversible panel 30 mounted in and carried by 120 door frame 29 Means are provided for selectively mounting and fastening reversible panel 30 in door frame 29 These means may include a plurality of thumb screws 32 as shown in Figs 5 and 6 or a plurality of 125 spring clips 33 as shown in Figs 7 and 8. Door frame 29 is further mounted by means of hinges 34 to cubicle 13 and is held in closed relation with cubicle 13 by closure screws 35 130 the disconnect position by rotating screw 17 with pantographs 16 supporting switch 10, 11 or 12 in horizontal travel, as shown in Fig 1 This movement effects separation of primary and auxiliary contacts 21, 22, 70 23 and 24, the switch then being in the disconnect position Door 28 is then reclosed. To effect the test position as illustrated by switch 12, it is merely necessary to move the switch by means of screw 17 from the 75

disconnect position toward rear 15 of cubicle 13 until auxiliary contacts 22 contact the circuit auxiliary contacts 24. Figs 10 and 11 show a modification of the invention in which a panel door 128 has its 80 door frame 129 made integral with reversible panel 130 The door 128 is carried by its hinge members 134 which in turn are carried in hinged relation to cubicle 113 by hinge supports 136 presented by cubicle 113 The 85 panel door is fastened to cubicle 113 by thumb screws 132 Panel 130 is provided with a modified cutout section 143 for receiving the desired switch gear components. Panel door 128 is illustrated as being dish 90 ed inwardly Should it be desired to reverse the dishing thereof, door 128 may be removed by disengaging thumb screws 132 and lifting hinge members 134 from hinge supports 136, turn the door end over end so 95 that it dishes outwardly and reinsert members 134 in supports 136. It is evident that the described invention provides a simple solution of the problem of enclosing drawout type switchgear for all 100 positions of a switch In addition, it provides an inexpensive and practical means without resorting to complicated linkages or other devices necessary when a single hinged panel is utilized 105

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* GB784767 (A)

Description: GB784767 (A) ? 1957-10-16

Belt grinding machine for woodworking

Description of GB784767 (A)

PATENT SPECIFICATION 784,767 4,> ' Date of Application and filing Complete Specification: Oct 28, 1955.

t | i F r No30961/55. Application made in Germany on Dec 15, 1954. Complete Specification Published: Oct 16, 1957. Index at Acceptance:-Class 60, D 1 (A H 4). International Classification:-B 24 b. COMPLETE SPECIFICATION Belt Grinding Machine for Woodworking. We, PAUL B 6 TTCHER, ERNST BOTTCHER, MAX BUTTCHER, all German citizens, trading as Bottcher & Gessner KG, of Gasstrasse 18-20 Hamburg-Bahrenfeld, Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement- In known belt grinding machines, furnished with a long grinding belt a relatively short pressure shoe executes a reciprocating movement parallel to the running of the belt, when the object worked Upon is moving perpendicularly to said'belt. Such a pressure shoe, reciprocated from one end to the other of the workpiece, does not produce everywhere an even machining, because the single parts of the surface stay a longer or shorter time beneath the shoe, dependent on the co-operating of the workpiece's transverse and the shoe's longitudinal movement. Even if pressure shoe and workpiece move automatically, the reciprocating pressure shoe returns only periodically to the same spot during each stroke while meanwhile the workpiece, even if it advances uniformly is pushed forward a correspondent step relative to the shoe A smooth even shadeless finish is therefore very difficult and depends on the skill of the attendant Compared with a cylinder grinding machine, working continually over the whole width of the machine, the belt grinding machine has only a -small efficiency When the shoe is operated by hand, the moving of the shoe also requires great bodily strength. The object of the invention is the construction of a belt grinding machine, in which, similar to a cylinder grinding machine, the abrasive is continuously in contact with the surface of the workpiece all over the whole width of the work table of the machine to produce a uniform coherent surface, when lPrice 3 s 6 d l the workpiece is moving onward. A simple lengthening of the pressure shoe all over the width of the machine does not present any useful results because of the big lengths of the workpieces 50 The contact length between a grinding belt and the surface being worked upon is limited by the filling-up of its abrasive graining with grinding dust A satisfactory grinding effect at the leading end of the workpiece would 55 already diminish in the

middle part and almost disappears totally at the trailing end. The capacity of the grinding belt would be overcome by the necessary high grinding pressure and power requirement necessary 60 for the large pressure surface Besides this the grinding belt is working blunt on a great part of its way in consequence of the accumulation of dust and therefore produces too much heat 65 These difficulties are overcome by this invention by providing a long stationary pressure beam extending over the whole width of the work table of the machine, each grinding grain however sweeping only over a part of 70 the length of the beam This is attained by mounting a comparatively narrow pressure beam slantwise to a corresponding wider grinding belt Thus the length of the grinding path for each grinding grain is no longer 75 determined by the length of the pressure beam, but by its width in connection with its slanting position, and all over the length of the pressure beam sharp grinding grains uniformly come to action The thus obtained 80 shorter grinding path may further be shortened at pleasure by notching the correspondent parts of the pressure beam. With such a method a continuous grinding effect is achieved over the total length of the 85 pressure beam without excessively lengthening the path of the grinding grains below the pressure surface or the latter itself The slanting position of the pressure beam is chosen such, that the grinding belt attacks 90 uniformly all over its width and over the whole length of the workpiece. The known advantages of the belt grinding machine can be maintained with such a long and stationary pressure beam only in case the latter is pressed on to the belt over the whole length equally elastic and soft To this end the pressure body of the beam may be constructed of any material with appropriate natural elasticity or may also be assisted in its elasticity by additional elastic elements (e.g pneumatic means) Such construction is no essential part of the invention. The invention is illustrated, merely by way of example, in the accompanying drawings, in which:Fig 1 shows a scheme of the new operation of the belt grinding 'machine, Fig 2 shows a section of the pressure beam in the plane II-II of Fig 1, Fig 3 shows a front elevation of the machine, Fig 4 shows a plan view of the same machine. In Fig I the new position of workpiece, grinding belt and pressure beam to one another are shown Over two pulleys I and 2 is running a grinding belt 3 in the common way This belt 3 in its middle part is shown broken away to make visible the parts lying beneath On the belt 3 at an angle W obliquely to its running direction is arranged a pressure beam 4 Beneath the belt lies the workpiece which is arranged such in regard to the pressure beam, that its feed as shown by the double arrow occurs right-angled to the pressure beam.

Fig 2 shows in section a simple embodiment of beam 4, consisting of pressure case 6 and a pressure body of two parts 7 and 8 The pressing is done by the lower part 8 of the body, consisting of a material flexible in longitudinal direction and somewhat stiff in transverse direction The real high elasticity of the whole beam is effected by part 7, which is mounted between pressure case 6 and the lower part 8, and consists of high elastic material As shown in the Figure the pressure surface of part 8 is provided with notches 9 and 10, so that the longitudinal ribs 11, 12 and 13 only do the real work In order to obtain better conditions regarding friction and heat the surface of part 8 in a known way is covered with a layer of felt 14 or some similar substance. As shown in Fig 1, grinding belt 3 has a width a, while the obliquely lying pressure beam 4 has the considerably smaller width b. The slanting position is chosen such that the pressure beam though being small in width, nevertheless covers the whole width of the grinding belt, so that the latter does its work in full width A grinding grain moving in the direction of the arrow on the belt from right to left over the total length of the workpiece travels under the pressure beam over a distance c, being considerably shorter, than the length of the workpiece This effective path c is not determined by the length of the workpiece, but by the width b of the pressure 70 beam in connection with the angle is Sinde the pressure surface of the beam is provided with notches 9 and 10 (Fig 2) the grindihg grain really grinds only while passing ovdr the ribs 11, 12 and 13 and the distances'd, e 75 andf Instead of a grinding path equal to the length of the workpiece, by the new arrangement a considerably shorter grinding path is obtained, consisting of the three sections d e, andf 80 Fig 3 and 4 show a belt grinding machine operating according to the method described above. The machine frame consists of a left and right pillar 15 and 16 and a top and bottom 85 traverse 17 and 18 At the left-hand side of the machine is mounted an electro motor 19 with the driving pulley 20 A suction hood 42 is provided to suck off the dust On the right hand side of the machine an idler 90 pulley 22 is mounted to a tensioning device 21 of the usual kind A grinding belt 23 is running over the two pulleys 20 and 22. Angle levers 24 and 25 with stationary shafts 26 and 27 are pivotably mounted in the upper 95 traverse 17 To the horizontal arms of these angle levers 24 and 25 is articulated a pressure beam 28 The vertical arms of the levers 24 and 25 are connected by a bar 29 so that the beam 28 swings up and down in its horizontal 100 position when the levers 24 and 25 swing out. Beneath the beam 28 a pressure beam case 31 is mounted pivotably round

bolt 30 by means of screws 32 and 33 Slots 34 and 35 permit the beam case 31 to swing round bolt 30, 105 dependent on the width of the grinding belt and the length of the workpiece 36 Further at point 38 a hand lever 37 is mounted pivotably to the upper traverse 17 By means of this lever 37 pressure beam 28 is pressed 110 down to workpiece 36 The weight of this pressure and suspension system is counterbalanced by a spring 39 arranged within the upper frame 17 between a nose 40 on the bar 29 and a stationary bolt 41 115 In a vertical guide 43 on the bottom traverse 18 is arranged a guided rest 44 on to which a supporting frame 45 is mounted. This frame 45 bears two round bars 46 and 47, which serve as a guide way for the rollers 50 120 of the worktable consisting of a frame 48 and the ledges 49 screwed to it Furthermore at the front side of frame 48 a round bar 52 is arranged on three supporting noses 51 on which bar a fence 53 is attached which may be 125 shifted as required A hand-wheel 54 serves to keep the fence stationary in a desired position The workpiece 36 will be aligned along fence 53 on the ledges 49 Rest 44 together with the whole work table can be 130 784,; 1 i; 7 784,767 adjusted according to the thickness of the workpiece by means of a threaded spindle 55, bevel gears 56 and 57 and a positioning shaft 58 rotated by a hand-wheel 59 By turning the rest 44, the direction of the feed of the workpiece can be kept at right angles to the respective position of the obliquely arranged pressure beam case 31. In the shown example the feed of the workpiece is effected by a reciprocating work table. This table may be reciprocated by any known automatic means and may also be replaced by continually driven endless chains or caterpillar chains.

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