US2836121A - Pumps - Google Patents

Description

May 27, 1958 l.. H. BRowNE 2,836,121

PUMPS ll (D 'h SJ v r INVENZIUR.y

- LINDSAY H. BRowNE ATTORNEYS May 27, 1958 L. H. BRowNE 2,835,121

PUMPS Filed June 12. 1953 3 Sheets-Sheet 2 FIG. 2.

I N f3 v INVENTOR. nnllllllllllllllll iBS/AY H- BROWNE ATTORNEYS May 27, 1958 1 H. BROWNE 2,836,121

PUMPS Filed June l2. 1953 5 Sheets-Sheet 5 "HH- l MUL Mb- LILMHLLLLL- l LLIi .rd mi? Fl 6.9. 3o 32 INVENToR.

LINDSAY H. BROWNE ATTORNEYS nited States Patent PUMPS Lindsay H. Browne, Westport, Conn.

Application .lune 12, 1953, Serial No. 361,225

6 claims. (ci. ies- 44) delivery of liquid is achieved despite the use of pulsators. As pointed out in the last mentioned application, a pair of pulsators may be 'so operated that, when supplied with a continuous flow of `driving liquid, they will provide a substantially continuous ow of the liquid being pumped. The statement that the flow is substantially continuous does not here imply that there is any appreciable deviation percentagewise from accurately continuous ow. Actually, the only deviation from precise continuity is involved in the occurrence of transient pulses of short duration which are more in the nature of sound Waves than measurable deviations of flow rate. These transient shock pulsations, however, have considerable amplitude and give rise to noise and vibration of the pumping system which is objectionable. Several sources of these transient shocks are recognizable. To provide truly continuous flow, it is necessary that both pulsators should have their inlet passages open to receive driving liquid 'simultaneously for at least short periods.. Assuming that one pulsator is substantially, expandedA while the other is contracted, and that the inlet is opened to the latter before the inlet to the former is closed, the fact that delivery is 'against high pressure and that thepulsators themselves have, for proper operation, substantial tendencies to collapse, it will be evident that upon the occurrence of the conditions just noted the driving liquid will tend to ow from the expanded pulsator into the collapsed pulsator to fully or partially equalize the expanded conditions of both. When this action takes place, the inlet valve of the liquid being pumped corresponding to the originally expanded pulsator will transiently open. Since any valves which are used have inertia, the result ot' this condition is to produce a shock in the system. rThis shock, however, does not involve occurrence, 'for a continuous supply of pumping liquid to the ,pulsators, of substantial discontinuity in the flow of :liquid being pumped; the transient involved is-ess'en'tially the result ot' interaction in the pulsator systembetween'thetwo pulsators andy the chambers interior and exterior tothem. The sudden pressure changes accompanying this constitute the cause of the shock. Y

`risecondV source' or" shock appears to accompany the beginning of-exhaustof the operating liquid from a pulsator, While Vthe liquids involved and the rubber material of the pulsators :are substantially incompressible,

very slight lag, and Considering the quite high pressures which are in practice generally desirably provided by this type of pump, there may be a substantial backward transmission of delivery pressure through the delivery valves before such valves can completely close. Reference is here made to pressure because the actual backflow of liquid is very small, and essentially the action primarily involves a transient transmission of pressure. The result is to cause compression-type transient shock waves to be transmitted in the system involving, in particular, a noticeable thrust on the distributing valve for the driving liquid.

The foregoing sources of transient pulsations accompany, particularly, conditions of high pressure of delivery. When the discharge pressure is low, transient pulsation's also occur due to the fact that the pulsators are necessarily of such character that they Will tend to collapse :against a substantial applied internal pressure. For example, in a typical operation, it may require a pressure of iifty pounds per square inch to provide substantial initial expansion of a pulsator. The pulsator spring characteristics will not normally be identical, land shock conditions will here also arise due to the dilerent tendencies of the pulsators to collapse, probably coupled with and aggravated by the lag of the valves in respective closing and opening.

lt is the general object of the present invention to provide improved pumps of the type just described in which the transient shock conditions which have been discussed :are minimized. Other objects `of the invention are concerned with improvements in various structural details of pumps particularly designed for delivery of liquids at high pressures and in continuous ow fashion.

These and other objects of the invention will become apparent from the following description read in con-v Figure 2 is a horizontal section taken through the driving liquid distributing valve and associated parts of the Pump;

Figure 3 is a vertical section taken through the dis-..

charge and inlet valves for the liquid being pumped and through the outer ends of the pulsators; and

Figures 4 to 9, inclusive, are diagrammatic sectionsV showing various 'successive positions of the driving liquid distributing valve during a half cycle of its operation. t f

The particular spatial arrangement of the various partsl or' the pump is not of major consequence and, accordingly, various elements are indicated diagrammatically in rather arbitrary location. A driving motor 2 serves to drive through shaft connections indicated at 4 reduction gearing indicated as located within a housing 6 by which, in turn, there is driven a shaft 8 carrying a crank 10 which through link 12 and pin 14 serves to reciprocate a slide 16 in a guideway 18 provided in a valve block 2). The various elements so far described are desirably located within a pump housing a portion of the wall of which is indicated at 21, this housing also enclosing a primary pump 23 (Figure 2) which is driven -by the motor 2. The pump 23 may be of any of a large variety ot' positive types. It has been found, for example, that one highly satisfactory form of pump is of multiple piston, Variable delivery type, which is capable of providing an `output reasonably continuous and free from pulsation. In such a pump, for example, variation of displacement from zero to some maximum capacity may be controlled by a manual adjusting device, though the adjustment of the pump may be automatically controlled either pneumatically or electrically.- Rotary piston or other types of positive variable delivery pumps may also be used. The particular driving pumpl here useddoes not, in itself, constitute a part of: the invention, the invention being rconcernedonly Withthe use of a positive pump desirably having substantially uniform displacement, andunder some'circumstances, desirably` adjustable asV toV de'- livery rate'. 'A constant rate pumpV may -be used where adjustability is not required. Conveniently, Vthe housing which encloses the elements described,Vv including the pump, mayrprovide an oil sump from which oil maybe pumped through theV system with delivery backA to the sump; Theoilused maybe any' suitable lubricating oil Vairdinay servenot only as the driving liquid but also for lubrication'of the'm'echanically operating parts.

A valve cylinder 26 is located with a press'iit ina borc 2.2i- 'ii1 the block 20, and arranged to' reciprocate in cylinder 2'6"V is a'driving' liquid'- distributing valve generally' designate'd '28;' This'valve comprises the main pistons130 and 32 and' end pistons' 34' and '36:' The spindle ofthe valve is 'bored a'tits endsltofreceivc'rods'BS'whichare arranged to be engaged'by discs' 22' threaded'on studs 2S' secured in' the end's'o the slide 16, th'e' discs-being located in' binding'con'dition against therods`38 and held' byloclr nuts.

` The purpose 'ofthe arrangement just described is to' provide'axiahadjustability 'of the valve 28"with r'esp'ect'tothe` slideA 16' to provide for proper' phasing' of 'its' respective c'i'peratio'nsV as' hereafter' described. Through' the c'onnec;

Y tions' from crank 10"the"va'lve' is' given' approximately simple harmonic motion for control ofV the' driving liquid ow.' A centra'lport 40 is provided'in 'block' 20 and cylin` der 26'to' servev for" the introduction ofoperatin'g liquid through' pipe 41' from the pump 23'. Y

Various p'orts'are provided inV 'axially displaced posi- Ytionsalon'gthe cylinder 26 and providecommunication betweenlitsbore and annular' spaces about the cylinder provided' in the' block' 20. Each of "these ports desirably consists'of a number of radial holes-through the cylinder, as'indic'ated in yFigureV l., to provide 'free' iiow of the driving liquid',. but for' convenience will be hereafter referred to in' the'Y singular. PortsY 421' and' 44 provide for' delivery' of' the driving rliquidfro'm th'ecentral' portion of'thewcylinder 26. These ports communicate withthe spaces 46V and 48`in the blockZO Forts 50 and' 52 provide for the exhaustY of driving liquid from. the pulsators andcommunicate with the spaces S24-and 56 inthe block 20. Y

' Ports Siand 60" provide, for exhaust o'f'the operating liquid from-thecylinder and' communicate withrthe spaces 672.y and VM in the` block. The spaces 62 and, 64 are; re-

spectively port'edat 66'fand68lto connectingpipes: 67 and 69 which serve to returnl theV exhausted driving',liquid'toV Y tl'iesurnp.Y

A's Will. appear hereafter, the valve pistonsV serve to control iiows through the various cylinderports.

VThe spaces 54 and` 56 are in communication with passages 70 andr72in the yblock 201 Spaces 46 and 4Sfcommunicate with the openings through valve seats 73' and which are, respectively, controlled-by ballcheclcvalves 74jand'76above which, as viewed in Figure 2, are located passages 75 and 77 communicating, respectively, through lateral passages 90"and 92y with the passages 70 and 72.

Inwardly. directed tins 93 guide the balls' and provide 'for f passage of liquid 'by the balls. Springs 82 VandA 84 serve to urge 'the balls 74and 76 towardseated position, these Y springs beingl'ccated within plugsV S76. andV 8;V inthe pas-` sagesf75-and 77`the plugs beingproviddV with packing to provide' against leakage from these passages. Snap rings 79y and 81` hold the Yplugs 8'6- and 88 in position. VThe bores 70 andi 72 are in communication with. bores'l 99 and 97, respectively, provided in.a.'block 94 whichlisY vmounted on the wall 2110i the housing. and serves to support, in an: opening through this wall,.the block 20.v Sealing hetweenthe' block` 20 Vandblocl:v 94 at Vthe passages is provided by O" rings as. illustrated in Figure 2. Communicating'with the bores 97 and 99'are tubular llers 96 43 Y and- 98 forV pulsators'Vv whicharedesignated generally at- 100 and 102. These pulsators 100 and 102 are of the same construction illustrated most clearly in Eigure 1. Each comprises a metal base 104 to which is molded a thimble 1.06V Vof rubber, the rubber used being desirably of synthetic type capable of withstanding lubricating oil in its interior and the liquidi being' pumped lon its exterior. Each pulsator also comprises a base 108 of metal bonded to an outer thimble 110 of'the 'same nature as the thimbleV 106. Desirably, this double arrangement of thimbles is provided for eachpulsator s0 as to avoidjdisastrous results in the event thatl oneY ofthe thimbles becomes rup tured. Actually, either willsutice for pumping, and while both are in proper condition, they effectively provide a unitary pulsator. The thimbles :106 and 110 are both of such construction as to tend to'collapse to Vnormal con- 'Y dition illustrated in Figure l against substantial pressure differential ineXcessf-of atmospheric pressure. This is of great 'importance for'practicral operation since, otherwi'se" if the' inlet valve of a pulsator should stick inA closed 'conf' dition', a thmble incapable of suchicolla'pse wouldremain' distended and: upon subsequentV expansion wouldengagc' theV walls ofg its/chamber andl possibly *be extruded; into the valve passages with resulting rupture. Collapsev of the thimbles'fis limitedz by the presence of the metal illers 96 Y andY 98` which are provided'V withV smallradial openings` 1-12 tol providey free passage of' the operating liquid' but" which are' so small' a'srto'prevent extrusion through them* which is'not shown but which' maj/"serve to deliver .le'ali ing liquid to a safe location. in' the' event thatthe'v liquid' being' pumped is of a dangerous character'. i Y

A block 'V serves' to' provide chambers' exterrxa'l"toV the pulsators' and mountings for" inlet andoutle'trvalve's; Y

for the 'liquidbeing pumped; This'block" 1203is'p'rov1 e with` bores 124 and' 126 receiving'the'pulsators 100i an'dl'Y 102, respectively; The' block 120 is' clamped byflolt's' 122' against 'the' thim'ble base`s`z10`8"and 104 4 and/the blockY 94', there'being'interpo'se'd O'rings'fa's,indicatedin'Figure 1 to' 'provide' p'a'cking's'fb'etween'V these elements" capable ofwithstanding'th'e high pressuresinv'olvedin thep'umping'.

The assembly thus'provided is particularly desirable for ready'dismounting-for the purpose of cleaning the various elements' which come' in' contact with the `liquid being pumped'. f Y ,Y

Inlet and outlet valves 128 and 132, respectively, are provided in removable housings in communication. with the' chamber provided at 124 and similar valves 130 andA 134 are provided in` association with chamber 126. The valve housings, one of which isY designated V136,- arel readily removable and are suitably packed 'by O rings.

An. inlet header. 133V is provided. withY a passage. 140 communicating with both inlet valves 128 and-130 andY communicating `with the.Y delivery valvesfV 132v and. 13,4-

and. with piping 148 for delivery of. the: liquidi; being pumped. Theseheaders arek clamped to Ithe'-, block- 1201'Y by. suitably arrangedlbolts', 0 rings providing; the' necesisarypacking. The operation of the pump may;nowbe':descrbotla Preliminarily,. it mayV be` remarked that the"rateg0f rotation of Ythe',j shaft. 8 forthe'purp'ose-of Yreciproca'tinge` the distributing valve 28 through its cycles isxsuch that,`

considering the maximum delivery of pump 23, if the delivery rate of the pump is adjustable, the pulsators will not be expanded during any cycle to such extent as to cause them to engage the walls of their respective chambers. Variation in delivery rate of the pumping liquid by pump 23 then merely involves less expansion of the pulsators to provide corresponding `displacement of the liquid being pumped.

Reference may now be made particularly to Figures 4 to 9, inclusive, with additional reference to Figure 2. There may be rst assumed the conditions involved when the valve 28 occupies the position illustrated in Figure 4, i. e. its extreme left hand position, as viewed in the gures. Under such condition, the port 42 is in communication with the supply port 40 for the operating liquid which will then be ilowing past valve 74, shown as open in Figure 2, and through passages 90, 70 and 99 to provide expansion of the pulsator 102. As this ow continues, the pulsator 102 reduces the volume in pumping chamber 126 providing outflow of the pumped liquid past check valve 134. The corresponding inlet valve 130 is closed. Outilow port 50 is closed by piston 30. The inlet port 44 for pulsator 100 is closed by piston 32. Ports 52 and 60 are in communication with each other through the space between the pistons 32 and 36 and are also in communication with the outlet port 68. While check valve 76 is now closed, the interior of pulsator 100 is in free communication with the outlet and this pulsator will be in collapsed condition under its own resiliency, the check valve 128 having opened to permit the chamber 124 to receive liquid being pumped. The check valve 132 will be closed under the high pressure of the discharge.

As the valve 23 moves toward the right from its left hand dead center position, there will be attained the position illustrated in Figure 5. The piston continues to close port 50 and will not then have started to close the port 42. Port 44 remains closed by piston 32, but this piston will now have closed the port 52 cutting oli communication between the interior of pulsator 100 and the discharge port 63. Actually, at this time, the pulsator 100 will have been fully collapsed and, consequently, ilow through the port 52 will have ceased before the piston closes this port. inasmuch as port 42 is still open for the passage of the operating liquid, the pulsator 102 will continue to expand.

The next event is the location of the valve 28 in the position illustrated'in Figure 6, which position is characterized by the beginning of opening of port 44 to the operating liquid. As this port 44 is cracked open, there would occur a tendency for iiow to take place from the expanded pulsator 102 to the interior of the collapsed pulsator 100. lf such action occurred, there would be produced, in view of the high pressures involved and since the discharge valve 134 is open, a transient shock z due to the interchange of liquid from one pulsator to the other. However, in accordance with the present invention, such a transfer of the operating liquid is prevented by the closure of check valve 74 under the action of spring 82. This check valve may close because, even though port 42 is open to the operating liquid supply, the pressure exerted inwardly by the pulsator 102 due to its expanded condition exceeds the inward pressure exerted by the collapsed pulsator 100. This condition continues, in fact, as the pulsator 100 expands due to the ow of operating liquid thereinto, inasmuch as until it receives its full volume of operating liquid it will be less expanded than the pulsator 102. Accordingly, the incoming operating liquid following the attainment of the conditions illustrated in Figure 6 will ow only into the pulsator 100. As pulsator 100 expands, its delivery valve 132 will open providing outflow of the liquid being pumped. Valve 134 corresponding to pulsator 102 will have closed due to the fact that a very small amount of The condition existing, therefore, is that for a short in terval after the attainment of the conditions illustratedof possible slight leakage) through port 42 in either direction. If any slight leakage occurs, it would be from pulsator 102 past check valve 74 and through the space between pistons 30 and 32 into the pulsator 100 under a relatively small head due to dilferent extents of expansion of the pulsators. Such slight ow, however, will not produce any noticeable transient in the nature ot' a` When the position of Figure 7 is attained byl shock. valve 28, port remainsV closed. Flow either to or from the pulsator 102 is thus cut oli except for possible slight leakage.

When the condition illustrated in Figure 8 is reached, the piston 30 starts to open the port 50. Pulsator 102 is thus brought into communication through passages 99 and and the space between pistons 30 and 34 and port 5S with the outlet passage 66, 67. In the absence of piston 34, the sudden application of pressure at the left of piston 30 would cause the valve 28 to receive a sharp impulse toward the right. However, with piston 34 provided, there is involved an equilization of pressures effective on the valve 2S to avoid the occurrence of a transient at this time. Pulsator 102 now collapses due to its resiliency and produces an opening of its inlet valve to cause ilow of the pumped liquid into chamber 126. At this time, port 44 remains open so that liow of operating liquid continues to expand the pulsator 100.

The movement of valve 28 from the 'position of Figure 8 to that of Figure 9 involves nonew operation, the pul- Y sator 102 being completely collapsed before the position of Figure 9 is reached, while the pulsator 100 continues to receive operating liquid through the port 44.

lt will be evident that the position of Figure 9 corresponds to that of Figure 4 so that the return of the valve to the position of Figure 4 involves merely a repetition of the phases of the cycle but with inverse respect to the twov pulsators.

Despite the intermittent openings and closing of ports, Y The Icontinuous supply of operating liquid involves necessarily total displacements of the two pulsators, first one, then possibly both, and then the other, in such fashion that the total of the displacements in the two chambers 124 and 126 remains constant.

the discharge is continuous.

The result is that the tlow of pumped liquid is also constant, assuming no leakage which, with suitably viscous operating oil, is actually negligible. paratus, this constant ow occurs with minimizing of transient shocks at the several changes of phases in the operation. t may be noted that the tiow through the inlet connect1on 142 for the pumped liquid is not constant,

and this might be considered a source of pulsations.

However, under ordinary conditions of supply at approximately atmospheric pressure, the magnitude of the pressure changes which occur on the intake side of the pump is small and, consequently, pulsations due to the intermittent intake are not of consequence. The pulsations which are to be avoided are those which involve transient changes of pressure of considerable magnitude and, in accordance with the present invention, these are kept down to a satisfactory level.

What is claimed is:

l. Pumping means compri-sing a plurality of expandible and contractible members, means providing With said members individual chambers of which said members form wall portions, inlet and outlet valves controlling ow to and from said chambers, and means for supplying driving liquid contraction ot pulsator i132 will occur as valve 74 closes. 'L5 to said members on their sides opposite their chambers In the present ap-Y ier.' expanding them and releasingl liquid therefrom l for rhein contraction,v the last Y namedmeans comprising;l a pump` supplying the drivingliquid at asubstantially constantjrateoverV the period ofja. plurality of complete cycles: of operation ofthe pumpingm/eans-L.apmovable j drivingliquid distributing, valvereceiving driving. liquid 'v from. said` pump, .driving means forsaidvalve; means providingafplurality of ported passages connected-.to theV respective members *and controlled by saiddistributing Y valve toreceive driving liquidvforpassage to the respective members, the distributing valve-controlling ow of driving liquid: Ainto said passages so (that,- atftinies,y flow occursA simultaneously thereinto',A check valves in said passages,

Y and means providing por-ted passages'L connectedtoV the respective members,k and. controlled by said distributing valve and through? which: last mentioned passages driving liquid Vis releasedfrom said members.v

Y 2. Pumping means comprising a plurality ofexpandible and contractible members, means providing-f` Withysad members individual chambers' of which said members form Wall portions, linlet and outlet valves controlling ow to and from said chambers, and meansA for supplying driving li'quidto said members on their Vsidesopposite their chambers for expanding'them andrfor releasing liquid therefrom for their contraction, thelast named means comprising a pump supplying` the driving liquid, a movable driving VIliquid distributing valve `receiving driving liquid from said pump, driving-means forV said Vvalve, means providing a plurality ofrported passages connected toV the respective members and controlled by'lsaiddistributing valve to receive driving-liquidrfor passage to therrespective members, the ydistributing valve controlling flow of driving liquid into said passages so that, at times, ow occurs simultaneously thereinto, check valves in saidpassages, and means providingported passages connected to the respective membersl and controlled by said distributing valve and through. which last mentioned passages driving liquid is released vfrom said members.V r y .a

3. Pumpingmeans comprising a plurality offexpandible and contractible members, means providing with said members individualchambers of whichsaid members lform y wallportions, inlet and` outlet valves'controlling oW to' and from said` chambers, means comprising a liquid distributing valve for supplying driving liquidftoV said members on their sides`V opposite theirchambers for expanding them and for releasing liquidv therefrom for their contraction, the

last mentionedmeans attimes-producin'g simultaneous ex' pandedconditions oisaid` members; and means for preventing'. iintercommunication between. the last mentioned sidesofsaidmembers during simultaneous expanded conditions, thereof, c Y

'4'. Pumping'means comprising arplurality of expandible" and"` eoutract'ible 'menti-fers, Ymeans providing with said members" individual chambers of which said membersz formfvvall portions,A inlet and outlet valves controlliugilovv"toeand from said chambers, and means for sup'- plying liquid to saidfmernbers on' their' sides opposite assenzitheir. rchambers for expanding; them andl for.' releasing. Y Y

liquidU 'therefrein` for their' contraction, ftlielast' named means supplying,v the-liquid at a' substantially' constant.

f uninterruptedtotal'rate to Said members' to effect a total" members, and means for preventing intercommunicati'oni,V

volumetricdsplacement ofsaid members due to their expansions which` is 'substantially constant throughout a complete cycle' ofiopera'tion, and Vs'aidhlavst'nan'red vmeans at times producing, simultaneouslyl expanded `coilditions ofY sai'd members, and'means for preventing,i'riterc'om-` mnnicationbetween the lastV mentioned' lsides of'said' members during simultaneous expanded conditions there'- of. Y

Y 5. Pumping means comprising a plurality of. expand-y ibleandA vcontra'ctible members, means providing'with said: members individual chambers of. which saidl inem'- bers form wall portions, inlet and outlet' Avalves ,conf trollingiiow' to and from'saidchambers',and' mea'jrfs for'L supplying liquid'to said members on'th'e'ir sides opposite" theirchambers" for expanding' tleni arid-r fot" reizea'sin'g liquid1 therefrom for' their' contraction, the' last named" means supi-dying'I the liquid" at' a' substantially constant"Y uninterruptedV total Yrate to said members t'o e'e'ct' Va' total volumetric Vdisplacement ofV said' members dueto"V n their' expan'sio'nswh'ich is substantially constant' tii'r'oug fr out' ac'om'ple'te' cycle of' operation, said last named'nl at times producing simultaneously' expanded' conditions."

of saidmember'ls,a'nd the .last named means' 'comprising' a' movable driving liquid' distributing valve', driving Vmean's for said' valve'V and mea-ns'for' preventing intercom'- i n munication between thev last mentioned' sides ofV said' mem'- j bers' during simultaneous expandedconditionstlrereof. Y Y

6. Pumping' means comprising a' plurality of`expand ible and contractible members, means providing'V said members individual chambers of which' saidl'me'me. bers form wall portions, inlet and outlet valves' controlarv ling'flow to andfrom said chambers, means comprising" a liquid distributing valve for supplying' driving; liquid, to said members on their sides' opposite their'chambers"y for 'expanding them and'for releasing liquidV therefr'ronif;`

for their' contraction, the' last mentioned means' at' tinre'sjjV producing simultaneous Vexpanded conditions'v of between the last mentioned sides' of's'aid members duringv simultaneous Vexpanded conditions'thereof, said members*L Y being contractible due to their resiliency to 'a predes;

termined initial condition despite pressure gradients across them'in excess of 'atmospheric pressure..

References' Cited in' the iilerofthis patent

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