US 1723874 A
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Description (OCR text may contain errors)
Aug. 6, 1929. E. LUNGE 1,723,874
PUMP AND LIKE DEVICE FOR CONTROLLING THE RATE 0F DELIVERY OF FLUIDS Filed Nov. 13, 1925 @Sheets-Sheet l F 1 50 W VT 4g@ 12,0104@ 15 l M i g5 v11s? ""r i" E/ Q 115115 1W -L .I I 111 Aug. 6, 1929. E. LUNGE 1,723,874
PUMP AND LIKE DEVICE FOR CONTROLLING THE RATE OF DELIVERY OF FLUIDS Filed Nov. 13, 1925 4 SheetS-Sheet 2 d k 23m, @Mm
Aug. 6, 1929. E LUNGE 1,723,874
PUMP AND LIKE DEVICE FOR CONTROLLING THE RATE OF DELIVERY OF FIJUIDSA Filed Nov. l5, 1925 4 Sheets-Sheet 3 Aug 6, 1929- E. LUNGE 1,723,874
PUMP AND LIKE DEVICE FOR CONTROLLING THERATE 0F DELIVERY 0F FLUIDS Filed Nov. 13, 1925 4 Sheets-5heet 4 Flgj.
Patented tug. 6, i929,
tihll'lElIi STATES PATENT OFFlC.
ERNEST LTINGE, OF LNDON, ENGLAlIilD, SSG-NOR T0 G'URTAULDS LIMITED, 0l? `LON- DON, ENGLAND, A. BRI'lSI-I COMPNY.
PUMP ND LiKE DEVCE FR COQTRLLING THE RATE F DEJIVERY GTE FLUIDS.
Application filed. November 13, 1925, Serial No G'., and in Great Britain November 20, 1934i.
invention is for improvementsin or vi to pumping appa attrs, and has tor ebiect to provide an improved construction et the same, whereby among other advantages, an unvarying rate oit delivery can be obtained. This feature is oit particular importance in the manufacture ot artiiieial silk, in which one oit the operations consists in squirting a spinning solution 'from a line nozzle in the form ot a filament; in order to produce a satist'actorily uni'torm product, it is necessary that the nozzle should be continuously supplied with a spinning solution at a uniform rate or pressure. lt is desirable that the supply should. be a continuous one, distinct trom one in which a uni'torm pressure is attained by using large reservoirs or the like, and it is therefore necessary to provide a pumpino apparatus which `shall deliver the solution at a substantially uniform pressure or rate.
iiny ordinary :term et reciprocating pump has a discharge which fluctuates and which consequently varies in pressure and velocity trom moment to moment; the extent ot the fluctuations of pressure and velocity can be reduced by using several pumps all delivering into aconn'non collector which supplies the squirting nozzle or nozzles, the pumps being so arranged that their delivery strokes are out et phase with one another'. For example, three single-acting plunger-pumps can, be actuated by cranks set 12( o apart, and in this case, although there Will still be tluctuations in the common delivery, such tluctuations will be of much less magnitude than those et thel discharge ot' any one o the pumps. But this method, even with the custoniary use of air vessels on the dclivery main, merely reduces the i'luctuations in extent and does not eliminate them.
it is an object of the present invention to provide a pumping apparatus so constructed to eliminate the iiuctuations ot velocity or pressure in the delivery main, which proceed trom a plurality of reciprocating pumps or other pumps which are like them in that the discharge oi an individual pump is intermittent or fluctuating, more nearly than has heretofore been practicable, and without the use of air vessels.
rlhe present invention, therefore, comprises in pumping apparatus, the combination With a pump or pumps having a cyclically-fluctuating rate of delivery, ot a above set forth are distinct from one another und each passage is appropriated to one end ol a pun'lp-cylindcr and is arranged to d liver in parallel with the conipanion passages to a cliamber common to all oif the pumps.
According to another feature et this invention, a viscose-puinpingv apparatus coinprises the lcombination with a pump or pumps having a cyclically-tluetuating rate et delivery, of a cam-actuated additioi'ial pump, the actifiating cam ol which is characterized in Vthatit is given a shape determinable 'from the delivery-curve et the compariion pump or pumps, and is used to operate its oivn pump at a iiuetuating rate producing a delivery trom that pump such that it counteracts by its own departures 'trom uniformity, the departures from uniformity that occur' in the rate of delivery et' the said companion pump or pumps.
This invention further comprises the conibination with a pump that to be used in combination with another pump or pumps having a cyclically-iiuctuating rate of delivery and that is actuated by a cam calculated as aforesaid to give a uniform rate ot delivery ter the group ot pumps, ot a deliveryvalve which controls the conduit leading from the pump towards the common outlet ot the piural'ity ot pumps, the valve being ot the kind which in its opening and closing movements does not alter the cubic content ot the pump charge, and a valve-operating mechanism that is actuated by the pump- Agear during pauses which occur betvveen the Working-strokes of the pump-piston.
This invention also comprises certain details ot construction and arrangement ot pumps as hereinafter described with reierence to 'the accompanying drawings in Which4 Figure 1 is a graph showing the variations in the rate of delivery of a pump or group of pumps;
liigure 2 shovvs a delivery curve for each rofl the two similar cam-operated pumps vwhich mutually counteract the variations in the rate of delivery of the other;
.Figure 3 is a graph showing the relation between the total delivery of a pump or its piston displacement; and time; n
Figure 4 is an elevation partly in section of a pair of pumps constructed in accordance with this invention;
Figure 5 is a transverse section on the line 5-5 of Figure 4;
Figure 6 is a plan in section on the line 6-6 of Figure 5;
Figure 7 is an elevation in section showing a group of pumps as illustrated in. Figures 4 to 6; and the arrangements for drivy ing them v View in plan showing a method of driving Cil CII
' the pumps;
Figure 15 is a section on the line 15-15 of Figure 14;
`Figure 16 is a section on the line 16416 of'Figure 14; and
Figure 17 is a part diagrammatic view in sectional elevation showing the arrangement of the pumps in a bath of lubricant.
Like reference characters indicate lilre parts throughout the drawings.
Before describing in detail the constructieniv of pumping apparatus in accordance with this invention; the method of determining the shape of the cam for driving the additional pump aloove mentioned will lirst he described.
VFigure 1 shows a graph or curve plot-ted on a horizontal hase-line 20, 21 which represents to a uniform scale the eihuxion of time; and the ordinates indicate vby their height the rate of delivery of the pump at any instant. The curve is drawn of an ar hitrary'shape such as might he met with in It will be seen that the delivery of the pump commences at thepoint on the time-base and the rate of delivery increases to the time 22, and then remains uniform during theperiod of time indicated by 22, 23. The rate of delivery then diminishes and becomes Zero at the time 24. rlie suction periodof the pump is indicated -at 2 25k, when the delivery-curve of course remains at Zero. The cycle then recommeuces in exactly the same form, ln this particular curve, the delivery-period 20; 24 is considerably longer than the suctioirperiod 24; 25, or; in other words; the pump has a slow delivery-stroke and a rapid returnor suction-stroke. l `urthermore, it will he appreciated that the accelerating and diminishing rates of delivery are represented hy curved portions of the graph. since the meehanii-al driving` of the parts renders it desirable to avoid abrupt or sudden changes in movement or rate of movement.
The object of this invention is to provide a uniform delivery rafle from the nozzle fed hy this pump, and this will conveniently he selected as being equal to the maximum rate of the deiiveiyv of the pump during` the period L3; this total uniform rate of delivery will then he represented hy the straight horizontal line 2o; 27.
"he total delivery from the pump during any speciiied time is measinfed hy the area enclosed hetween the curve of its delivery rate; and the time-base; that is to say; the total delivery of the pump during the time 20; is represented oy the area 20; 2S, 2E; 30, 22; 20, and similarly during any other period time. .if the total delivery is to he at a uniform rate represented hy the graph 2G; 27, it is clear that if one pump deliversl u, quantity represented by the area hetween the curve 20; 2S, 30; and the hase-line 20; 2l; there must he a second pump which will give a delivery indicated hy the area ahove the curve 20; 29; 30; hetwecn that curve and. the horizontal line 26; 30; so that when these two deliveries are added together; the total is represented hy the area 20; 2G, $30; 22, which is a ligure of uniform height.
It follows, therefore7 that the curve 2l); 2S, 29; 30, referred to the line 2G, 2T as a hase; indie-tes the raie of delivery that in req ired from the additional pump, and the pump is therefore actuated hy a cani whereof the proiile is so shaped as to give this curve of rate of delivery.
In the preferred form of the invention, two pumps are used, and bot-h are cam-operated hy similar cams. This is most easily effected. hy setting out; as in Figure 2; upon co-ordinates 5G and 55, 57, the desired uniform delivery-curve 5T; 5S. llrithin die area between the lines 57, 5S and hij; ho, 'there is dra-wn convenient delivery-curve 53 which hears thn same relation to the line 5T, 5S a hase5 as it does to the line .75, o as a hase, or in other words, which is s vnr metiY al about a line 30, parallel with and midway between the lines 55, 5G and Iii; The curve 59 constitutes the rate-ofdelivcry curve of one pump when referred to the hase-line 5G; and also the rate-of-deliveryY curve of the co-operatine pump when referred to the hase-line i; 58. Since the lll() lub' lll)
lill) curve 59 bears the same relation to the` two base-lines 55, 56 and 57, 58, it follows that the cams for the two pumps are identical with one another, and. their angular' relationship is determined by the fact that the delivery-period of one pump is to start immediately the rate of delivery ofthe other pump starts to fall ofi.
llt may be pointed out here that the design of the cams may be derived froina consideration ot curves representing the relationship between total delivery 4(or displacement) and time, instead of rate of delivery and time, and such a curve is illustrated in Figure 3. The base-line 130, 131, represents to a uniform scale the eflluxion of time, and the vertical line 130, 132 represents the displacement of the pump piston from its inner end, that is to say, lengths measured upwards from the base-line represent the amount which the piston has moved outwards on its delivery-stroke from the beginning thereof.
rithe curve or graph showing the displacement of the piston is illustrated as starting at 130, and in order that the action may be as smooth as possible, the curve at this point is tangential to the base-line 130, 131. The graph rises, slowly at lirst, but at gradually increasing rate up to the point 1233, where it is continued as a straight line, 1533, 13T-i, which is tangential to the curved part 130, 133. The piston, during the part i133, 13ans moving at a uniform velocity. From the point 134, the piston has to be slowed down, as it is approaching the end of its stroke, and the graph is again given curved forni 13a, .135, this curve being such that the line 138, 134;, is tangential to it at 134, and the line 132, 135, is tangential to it at 1.35.
From the point 135 the graph continues for a short distance to the` point 13G, parallel with the base line 130, 131; this represents a pause at the end ofthe delivery-stroke, when the piston remains stationary for a period during which the valves of the apparatus are adjusted to `a new position. The returnstrolre of the` pump is made more rapidly, being represented by the curve 13G, 137, 138 which is tangential at its ends to the line 132, 136 and the lese-line respectively so as to give a smooth action and is otherwise a smooth curve. From 138 to 139, the. graph coincident with the base-line, giving a period during which the piston remains stational7 at the inner end of its stroke whilst the valves are being readjusted. y
The shape of the graph 136, 13T, 1538 for the return-stroke is determined only by such considerations as will give smooth mechanical working. l
The corresponding graph for the conipanion pump is indicated at 141-0, 141, 1111.2, 1118, M11, M5, and is exactly sinnlar but is displaced in phase from the graph 130, 13d,
139. 'A shape of graph which gives suitable working is one in which thc portions 130, 133, and 131i, 135 are portions of paraboles adjacent their vertices. The portions 130, 1325, and lil-0, 141 of the two curves are exactly similar to one another but inverted and reversed. Further, it will be seen that the return-stroke of each pump taltes place during the period whilst the other pump is moving at a uniform rate in the middle portion of its delivery-stroke.
A particular construction and arrangement of installation comprising pairs of cani-operated pumps, which are suitable for pumping viscose or like liquids, will now be described with reference to Figures 1- to 10 oit' the accompanying drawings.
The body G1 of the device is preferably a casting with various passages bored through it from end-to-end, of which a ccntral uniform bore (32 acconin'iodates a controlling-valve. At the bottom and top there are bores (53, (Sli respectively which constitute a su pply-pipe and a return-fiow-pipe for the liquid; the supply-pipe 63 communicates with the valve-chamber by means of a vertical bore G5, and the valve-chamber opens by a vertical bore (i6 into a transverse bore which contains a manually-adjustable valve-niember 67. This member is capable of movement along its axis, to the left in Figure 5, so that communication can be established from the passage GG aforesaid, either to the outlet (38 or to a vertical bore G9 which coinmunicates with the return-flow-pipe ttl. The outlet passage G8 is extended in any convenient manner, for example, as shown in Figure d, to an outlet whereto the spinning-nozzle can be connected when the apparatus is used in the manu'acture 'of artificial silk. The valve-member G7 is limited in its lncwementsby a pin 71 engaging a slot 72 in the body of the device. This prevents rotation of the valve or other movement into an inoperative position` The pump cylinders are constituted by lon ;itudinal bores 73, 7st respectively, (see Figure 6) which contain plungers 75, 7G, these plungers being a close sliding fit therein. rlfhese plungers are operated by push rods 7"?, 78 which extend through openings of a suitable diameter into the pump-chambers respectively where they engage by their rounded ends the plungers aforesaid. The pump-chamber in each case is constituted by the annular' space surrounding the push-rods 77, 78 which are of less diameter than their corresponding plungers 75, 75.
'lllhe= pump-chambers communicate each with the valve-chamber G2 by means of an opening 79 (Figures 5 and G) bored transversely through the body 61 from front to bach.
The valve controlling these two pumps is a cylindrical. plug 550 lit'ring accurately in lOl) CII
vot the transverse bore 79 and therethrough with one or other of the pump-chambers 7 3, 74. Thesetwo recesses are so situated that they come into operation alternately, and both can not be simultaneously in use.
rlhe valve is also provided with two other recesses 86, S7 respectively, whereby the pump-chambers can be put in communication with the outlet-pipe 66. rlhese two recesses extend longitudinally along the valve for a greater length than the inlet-recesses '84, 85, and they overlap one another longitudinally* as shown most clearly in Figure 6, so as to permit ot communication being established simultaneously 'from both pumpchambers to the outlet.
It will be seen that all the passages and chambers in the pump are form-ed as straight-through bores, the ends heirg closed where necessary by removable plugs. This construction greatly facilitates the cleaning and maintenance of the device and at the Asame time renders the machining operations simple and the construction therefore inexpensive.
The operationot this device is as follows.
The pistons 75,76 are reciprocated by cam- 4mechanism constructed in the manner described with reference to Figure 3. The Jiston 75, in the position illustrated in Figure G has ust commenced its delivery at its mairiinum rate and the piston 76 has just stopp xd delivery. The valve 8() is now moved towards the right in Figure 6 so as to bring the recess 84 into alignment with the passages 79 and G5. The outlet recess 86 is thereby shut oil from communication with the outlet G6 and is also shut ol'l from the cross Iy ru .L 0f*- 7 Y passage 49. lhe outlet rece-ss or, hon ever, still'provides communication troni the cylinder 73 to the outlet. As soon the valve has completed this movement, the piston 7 6 'makes itsrapid return-stroke towards the .right 1n Figure 6; on the comple ion oit this stroke, during which a fresh charge is drawn intromfthe supply-pipe 63, thepiston pauses again, and the valve 8O is moved hack to the position shown in Figure 5. The piston 75 thereupon slows down andsimultaneously the piston 76 commencesV its delivery-stroke so that theyv are both delivering simultaneously, the total amount delivered being such as to maintain the desired uniform rate of delivery. This continues with the piston 75 slowing down unlil it stops, having reached the end of its deliverystroke, and the piston 76 is delivering at the maximum rate. The piston 75 pauses whilst the valve S() is moved to the leil't in Figure G so as to open communication from the supply-pipe 63 to the cylinder 73 through the recess 85. rlhe piston 7 5 then makes its rapid returnor suction-stroke and pauses at the end thereof. and during this pause the valve is brought hack again to the position illustrated in l `igure G. Meanwhile the piston 7G has been maintaining the full delivery at a unilorm rate. lllhen the piston 7 5 starts its deliverystrolre, the motion olf the piston 76 slows down, so that their joint delivery is at the desired uniform rate. The piston 7G then reaches the end ot its stroke and stops, and Jthis completes vthe cycle, the various parisl having now returned to the position illustrated in Figure 6 irom which they started. This cycle ot operations is repeated continuously, so that a perfectly uniform rale ol'i delivery from the outlet is obtained.
It will he appreciated that pumps mayhe constructed in various ways in accordance with this invention, and the particular a1'- rangement illustrated wherein the pistons and valves move endwise, is selected so that a number ol pump-units can be assembled together as shown in Figures 7 and 8, and all operated simultaneously by a sin glo driving mechanism. Referring to these ligures, it will be seen that a number ot the pump-units are arranged end-to-end in alignment with one another, cach moving part of each unit abutting endwise the corresponding moving part of the next unit and operating it. 'lhe supply-pipe lll-3 and the return-l'low-pipe (S-l similarly ali gu with Vone another to provide a channel extending tl roughout the whole length ol the series ol" pumps. At the end oi the series, a special unit 88 is provided to serve as a guide tor plungers Si), 90, 91 which are aligned with the valves and. pistons respectively. These plungers are provided with rollers whereby they engage each an operating` cam 92, 93, 94, respectively, so that rotation ot the cams causes an endwise movement ol the pluugers and of the corresponding parts ol the whole series oit' pumps. At the other end ol the series, the various moving parts abut the plungers 95 of a hydraulic or other lsuitable yielding pressure-device 9G which climats the return-strokes oi the various. parts. these strokes being ot course governed by the. profile of' the cam. lt will be appreciated, however, that the invention is not. limited to this particular construction of pumps, for each pair ot pumps could be actuated by its own cams, if so desired.
The viscose, or other liquid, is supplied lo the series of pumps through a pipe-connection 97 (see Figure 7) which communicates with a body-portion having passages registering respectively with the conduits 63, 6411, and which also has a conneetingpassage 98 extending between said conduits. At the other end or the series a separA unit 99 is provided with a .similar coi'inecriiig-passage 100, and conveniently this passage also communicates with a valve-controlled outlet 101, situated at the highest part of the system. 1n the passage 98 aforesaid there is provided a screw-propeller or other pumping device, whereby the liquid in the conduits G21, Gl can be continuously circulated during the operation oit the pumps .in order to ensure homogeneity et the material supplied to the various pumps. lWhen starting up such a series olf pumps, the viscose or other liquid is allowed' to flow in through the inlet 97 so that it lills the conduit G3 and rises through Jihe connectie@passages 98, 100, and then fills the passage Gel. Any air in the system is driven out by the liquid through the outlet 101 whereof the valve is kept open until the liquid flows out oit it. It is thereby ensured that 4no air is permanently entrapped in the circuit and the pumping device in the conduit 98, which device is driven for example by the pulley 102, can be started, and then the cams can be set in operation to drive the pumps in the manner hereinbetore described.
When a number o'l pumps are assembled end-to-end in the manner illustrated in Figff ures 7 and 8, any suitable packing may be provided to ensure the joints of the cenduits 63, Gilbeing tight, and the various parts are made of such length that the assembly is automatically correct. 11n elastic or yielding packing may be used so as to permit a reasonable tolerance in the fitting together of the various parts. Provision may be made it so desired, t'or adjusting the length et' any or' the moving parts as illustrated on the end 81 ot' the valve-member in Figure (i, te compensate for variations in worlunanship, or accumulations et tolerance, which might atleet the sett' oli the various parts.
The method et securing the pumps to the bench is illustrated in Figures 9 and 10. 1li ehannelsection rail 1023 is secured on the bench, and the pump-bodies 104: are so shaped as to lit into it. Holes are bored through the side-walls el the channel to give a substantial clearance to the pins 105, and these pins are a close lit in locating-plates 10G, 107. The pins are also a goed fit in the .body o the pump. llhen the various pumps are first assembled, they are accurately aligned with one another, and the pins 105 inserted, with the plates 10G, 107 loose. '.llhe plates 10G, 107 are then locked in position, as by the bolts 108, so that the position of any pump-unit is accurately determined. By simply withdrawing the pin 105 the pumpbody can be removed for inspec tion or cleaning, and when it is replacechit has only to be aliv'ned, so that the pin 105 can be inserted, and it is then assured that the pump is properly aligned with the other units.
Pumping devices in accordance with this invention may be constructed in various ways, and Figure 11 illustrates a modification. In this case the pump-cylinders are arranged transversely to the valve-chamber. The pump-body 109 is provided with three bores 110, 111, 112 extending longitudinally through it and serving respectively as the supply-pipe, the valvochamber, and returnllowpipe. rlhe two pumps are constituted by plungers 1123, 114 reci,1)rocating in transverse bores 115, 116 rea Jectivelv, which eoinmunicate with the vaivechamber 111. The valve 117 is oit the same construction as that previously described, as also is the outlet with its controlling valve 118. It will be seen that this construction olf pump can be made ol;l a. smaller length, measured along the length olt the supply-pipe, than the construction previouslyA described, so that a larger number et' units can be assembled on a given length of bench. The pistons of each pump project transversely from the line et' the row oill pumps and they may be operated in any convenient manner, as lfor example, by the mechanism illust 'ated in Figures lll- 16.
Referring to these drawings, a number of the pumps or like devices for controlling the rate of delivery of the liquid are arranged sidebyside as indicated diagrammatically at 146 with their pistons projecting trans versely from the line el' pumps as indica-ted at 147, 1118.
il rectangular trame 149 surrounds the group of pumps and is constituted by four tramesmembers 150, 151, 152 and 153. 'lille member 150 at the liront is arranged to bear by its rear edge 15/l against the pistons 147 oit the group el pumps, and its front edge 155 is termed with the cam-surface whereof the shape is predetermined according to the movement which is to be imparted to the plungers or pistons la7.
To co-operate with the cam-surliace 155 there are provided two rollers 156, 157 which are mounted as shown in Figure 16 in such a manner that they can be traversed in a straight line longitudinally o'i the framemember 150, so that the trame is moved in accordance with the contour ot the cam 155, and in so doing moves the plungers 14:7. A pin 158 is secured on the underside oit the trame-member 152J and engages a straight slot 159 to constitute a guide it'or the trame 149, so that the frame is supported and guided in its operative movement at three points, namely, by the rollers 155, 157 and by the pin 158.
.Each of the rollers 156, 157 is mounted as shown in Figure 16 in a carriage or slide block 16() which can slide in a slot in the base-plate. Each roller also has mounted on its spindle a gear-wheel 161 which engages a screw-threaded spindle 162 which rotated at a uniform speed. The rotation of the wheel 161 received from the spindle 162 causes the roller 156 to roll on the surtace ofthe cam 155 and thereby traverses the roller along it. The roller 157 is similarly operated, and its screw-threaded spindle 163 may be oppositely-handed from the spindle 162 so that the two spindles can beV coupled together and rotated in one: direction to cause the two rollers to approach one another, and rotated in the. opposite direction to cause them to recede Jfrom one another.
A second group of pumps may be arranged 'as shown at 164 back-to-back with the iirst group 146, and operated by a similar mechanism at the other side of the bench. In this case the rear frame-member 152 may be used to operate the plungers ot the second group ontheir reverse stroke, and similarly, the rear member 165 of the second trame can operate the plnngers ot the first group on their rearward stroke. With this arrangement it is not necessary to use pumps in which the plungers or pistons are moved outwards by the pressure ot the fluid supply as above mentioned. Furthermore, with this arrangement the side-tramemembers are cranked as shown in Figure 15 at 153 in order to clear the other tramemembers and permit the desired relative movement of the iframes.
Any desired number of groups of pumps may be arranged along a bench and the screwed operating-spindles of all the groups may be connected together'and driven by a single mot-or at theV end. The operating mechanism is thereby simplilied and considerable economy in space is effected. It will be seen that the features of simplicity of construction and facility for cleaning and maintenance are provided in this construction with transverse pistons, as in the previously-described construction.
1n order to make clear the great flexibility of design which is possible with pumps in accordance with this invention, yet another construction is illustrated in Figures 12 and 13. In this case, the supplyand return-flow-pipes are indicated at 119, 120 respectively, and the valve-chamber 121 is arranged with its axis transverse to that ot the supply-pipe. The pump-cylinders 122, 123 are arranged in the same horizontal plane as the valve chamber, one on each side of it,parallel with it, and extending in opposite directions from the centreline of the supplyand return-flow-conduits. The valve 124 is reciprocated by any convenient mechanism, such for eX- ample, as a moving frame 125 underneath the pump, having an upstanding lug 126 to receive a pin 127 engaged with the end of the valve-stein.
T he other details of construction need not be described in detail, for it will be obvious that they may be varied within very wide limits without departing from the scope of the invention as set forth in the appended claims.
It will be appreciated that when a number of pumps as above described are assembled in a group and all driven by the same mechanism, it may be desired to slop the delivery from one pump without interfering with that ot the others, and it is for this reason that the by-pass valve 67 aforesaid has been provided. li? the delivery from a pump is to be stopped, it is only necessary to adjust the lay-pass valve so that the liquid delivered by it is delivered into the return-ilow-conduit inst ad ot to the outlet in the normal manner. Also, it should be noted that the type of controlling-valve which is used for these pumps is one in which the adjustment ot the valve l'rom one position to another does not. vary in any way the cubic content oit the charge or ot the chambers within a pump. rlhis is effected by providing recessed or notched members so that in normal workingr the recess is iilled with liquid, and this quantity or' liquid is moved bodily with the valve as it is moved from its open to its closed position, and vice versa. Moreover, the arrangement whereby the valve is operated whilst the pump-plungers are stationary is advantageous in that before a pump starts its delivery-stroke, the outlet-passage is fully opened so that there is no throttling o1Ll the How of liquid which might tend to produce unknown variations in the rate of delivery.
A further feature ot this invention relates to the lubrication of pumps and like devices as hereinbefore described. ln the manufacture of artilicial silk trom visa-ose, when the solution is ready for spinning` it is in a state in which it hardens on exposure to atmosphere and it is desirable that any such hardening ot the solution on parts ol the pump should be avoided, and Figure 17 illustrates diagrammatically an arrangement for obviating this dilliculty. The pumps are immersed in a solution which prevents hardening of the viscose and also prevents corrosion ot the pumps and associated parts themselves.
Referring to Figure 17, the pumps are indicat-ed diagrammatically at 166, and they are supplied with the spinning solution through a pipe-connection 167. The pumps are mounted in a trough-shaped vessel 168 which is filled to a depth sufficient to submessa/i merge them with a dilute alkaline solution, such tor example as a 1% solution ot caustic soda or a 1% solution of sodium carbonate. This may be supplied to the trough through a pipe 169 and a drain-cock may be provided at 170.
Means may also be provided for regulating the temperature ot this bath, such for example as pipes 171 through Which heating or cooling mediums may be circulated. Ethyl-chloride and hot- Water are suitable mediums, although many others may be used.
It is preferred to use an alkaline solution as above mentioned since it .is available as a by-product in the process oi manufacture and can readily be made of an appropriate strength tor the purpose above iinentioned. lt caustic soda be used it is desirable that its strength should be not more than 1%, or alternatively not less than as the intermediate strengths are apt to cause a certain amount of corrosion ot' iron or steel. Sodium carbonate can be used, however, in any strength up to say 10% Without objectionable corrosion occurring.
ln order to prevent any contamination of the alkaline solution by sulphuretted hydrogen or other sulphur-bearing fumes or gases which may be present in the atmosphere, a thin layer oit mineral oil or like material may be provided on the surface ot the bath.
llVhat l claim as my invention and desire to secure by Letters Patent is 1. n prunping apparatus, the combination olf a cam-operated reciprocating pump, an operating cam therefor Which is so shaped as to cause a pause in the operation at the end ot each stroke ot' the pump, a second cam-actuated pump, an operating cam thereior which is so shaped that the combined delivery ol" the two pumps is constant at all times, and further that a pause .in the operation is caused at the end of each stroke ot the second pump, delivery passages from each of said pumps which are distinct 'from one another, each appropriated to one pump and arranged to deliver in parallel With the companion passage.
2. ln pumping apparatus, the combination ot a cam-operated reciprocating pump, an operating cam therefor Which is so shaped as to cause a pause in the operation at the end ot each stroke ot the pump, a second Cain-actuated pump, an operating 'am therefor which is so shaped that the combined delivery ot the two pumps is constant at all times, and further that a pause in the operation is caused at the end of each stroke ot' the second pump, supply and delivery passages tor each of said pumps, valve means controllingsaid passages and a valveoperating mechanism which is actuated during the pauses which occur between "the strokes ot the pumps.
3. In pumping apparatus, the combination of a cam-operated reciprocating pump, an operating cam therefor which is so shaped as to cause a pause in the operation at the end of each stroke ot the pump, a second cam-actuated pump, an operating cam theretor which is so shaped that the combined delivery ot the two pumps is constant at all times, and turther, that a pause in the operation is caused at the end oi each stroke ot' the second pump, both ot said cams being further so shaped that the maximum rate ol delivery ot each pump maintained through an appreciable extent of movement ot' the cam, as distinct 'from being merely instantaneous.
ln pumping apparatus, the combination ot a series ot plunger-operated pumps arranged in a row with their plungers disposed and movable crossvvise ol` the row, a member mounted tor movement in a single plane in which the pump plungers move eX- tending lengthwise ot the row in operative engagement With said plungers of all of the pumps, and means for moving said member in direction transverse to its length for operating simultaneously all oit said plungers.
5. In pumping apparatus, the combination ot a series of plunger-operated pumps arranged in a row With their plungers disposed and movable-crossivise of the row, a cam-member having a fiat face. opposite its cam tace, engaging said plungers by said fiat face, abutments engaging said cam tace and means 'for trayersing said abutments longitudinally of said cam tace.
6. ln pumping apparatus the con'ibination 01"" a plurality ot cam-operated reciprocating-plunger pumps arranged in a row with their plunger-s disposed and movable crossu'ise ot the row, a cam-surface mounted tor movement in a single plane in which the pump-plungers move and extending length- Wise oit.' the row in operative engagement with said plungers of all the pumps, a second plurality ot cam-operated pumps similar to and co-operating respectively with said first mentioned plurality, said cam-surfaces being so shaped that the combined delivery ot all the pumps is constant at all times and further that a pause in operation is caused at the end et each stroke of each plurality of pumps, and means for moving each cam-surface in a direction to operate simultaneously all of its associated plungers.
In testimony whereof I atlix my signature.