US2159467A - Pressure fluid motor - Google Patents

Description

May 23, 1939. w. H. WINEMAN y PRESSURE FLUID MOTOR Filed Sept. 28. 1936 2 Sheets-Sheet l WMM l di?? num,

May 23, 1939.

W. H.l WINEMAN PRESSURE FLUID MOTOR Filed Sept, 28, 1936 2 Sheets-Shea?l 2 0 gm. fw

IIIIIIIIIII Patented lMay 23, y1939 Pli.'rir1\l'|l OFFICE A Y v u fvpnltssoltilrsirioron Portey County, Ind., assigner to 'Sullivan'Ma- Achinery Company, a corporation'oi' Massai Y'sppriesosgspsientsr 2s, 19de, serra; No. 102,990

' 1' r20 Clal'nsr (Cl. 1217-132) Y Mir/invention .relates tomotora audio ,Certain aspects thereof more particularly to pump actua ating .;ir1oto,rs..v From another aspect itrglates tu cushioning devices. ,o Y o Mechanical pumping of oil wells is necessary when the stratum pressure isv inadequate to ,raise the oil to the surface, arida very Successful pumping apparatus used for this purpose includes cpm..- moniy o central source pfvrmotur Iluidosupplv, t. gether witha .number of cir-plausible chamber me: tors. .actuated by thellldflllpledgfl'om rdrn'f trui source and cachpperpting arrpumprraliged in the Well thlOllgh it Sollkorurodlina n such asi/stem a pressure yoi ,fromzOOto ,300. unda say, persquare inch is `culplovod Nfor f-llcctingthe l working .strokes of .tirepump operating motor,

and the,mororsexhaust-against abackpressure 0f l nemico to V10,0 ,poundfspersquare ,incluy Said 'back pressure being so determined toretard in a suitable manner Ythe ,downwardniovement v,of the motor piston and ,the parts Supported thereby. AThe pumping ',unitat. -each vWoll ,commonly com# prises a single-acting.,exnausiblefcliaiuber .motor provided ,withafrluiri-eotuated ,valvemechauism and thescmotorshave associatedowith-.thcm dash por oreushiouing frneansrso that .in thecventthat their pistons lose their loadsdue, -forfersarrrpla t0 sucker rodline breakage or to therupturing ofso pump packing;.0rl vthe .liner-the ,upwardxlllvgmerit of the motor pistonand .theattahe DOliQliPf roe-pump rod une ,mayuotfsriously damage the apparatus in its uncontrolled upwardmovcmeut, Apparatus for .shut-tins off .the motor ud Stillplv tofsaid pumping motorain :the @v ellbpf their making, a, strokenot under normal. workings G911- ditions, has been devisedandlputented by, me, s ee Ratentluofnzoali; andzthis apparatus is eiecy tive to shut down the pumping motor in the event of .a breakagcof VIAthe 'pump-rod liuepr the rupture; of a pumpgpacking, ,to protect: the. System save f orone possible facton When thernotor overtraveis .at vhigh, velocity, as would; occur when, the sucker rod line breaks tonite ,arsubsianial pressure willloeoloirilt2 up4 in .thescushion cylinder, and at vthe end of theushonng of the; rising motor piston this pressure Willtend to drive back down the motor piston and its vconnectedpaits andmperhaps cause serious damage during said downward movement of these parts. VIt would accordingly make a 4device which ywould bepractically .proof against Yany further serious injury, in the event of the rupture of a sllker rod line, if after the cushioning effect has been availed of, `the cushion pressure mightvbe quickly .bled away before it would have an opportunity to im# part a .substantial downward momentum to the motor piston and supported parts. I have devised an ap lziaratus flor this purpose, effective upon the completion of cushioning to relieve .the cushion pressure; and in .,thepform of the invention herein disclosed have rendered this pressure relief mechanism responsive to pressure changes Within the cushion cylinder, although'it Will be obvious that other and radically diierent control means might be devised within ythe scope of my invention. With this apparatus I have incorporated another mechanism which .per se formsfthe subject matter of a separate application (Serial No. 102,989) towit: lmeausfor locking the iiud distributing valve inenhausteeifectingposition when the sucker rod line or a packingl is ruptured, and thereby have provided la very ,simple and' effective complete shut-down device lfor stopping the pumping motor without anyharm whatever after such a rupture takes place.

It is an object of my invention to provide an improved motor. It is another object of my invention to provide an improved pump-operating motor having improved cushioning means. It is a further object of my invention to provide an improved pumpeoperating motor, having associatedtherewith means for .cushioning the motor in the event of the loss of load of the motor pistondand for venting the cushionzpressure before thesame has anopportunity to impart to the motor system,asthe cushion pressure fluid tends to .re-enpand, a high or detrimental velocity. It isyyet afurthc-ir object of my invention to provide an improved motorhaving associated therewith improved means operative upon material overtravel of thevumotor pistonto interrupt the operation of vthe fluid distribution means for the motor, to cushion. the abnormal motor piston movement, andto .release the cushion pressure which is huilt` in order that the motor may come to rest without detriment to itself or to supported and actuatedparts. 'It isyeta further 4object of my invention 'to' providean improved pumping motor having Iassociated 4therewith improved cushioning matisand improveddistributing valve controlling means in :order that cushioning of the motor may be gipctualiy accomplished and the motive fluid' distribution' to the motor interrupted and the cushion pressure released so that no violent downward vmovi-:ment of the motor piston and supported parts will take place. Still another object is v to n provide an improved cushioning device. Other objects and advantages of the invention will hereinafter vmoreA fully appear. jIn accompanying drawings, in which, for purposes of illustration, one embodiment which my invention may assume in practice has been shown, Fig. 1 is a view in front elevation showing a pumping motor of the character hereinabove mentioned incorporating my invention in its illustrative form.

Fig. 2 is a vertical section on a plane corresponding to the section line 2-2 of Fig. 1, some parts being shown in elevation.

Fig. 3 is a section, with parts broken away, on a still further enlarged scale, and' on a plane corresponding to the section line 3 3 of Fig. 2, showing details of the distributing valve mechanism and of the automatic control therefor.

Figs. 4 and 5 are sectional views on an enlarged scale through the automatic control device associated with the distributingvalve, these sections taken on a plane corresponding to the plane of Fig. 2, and respectively showing the automatic control device in its normal position and in its position assumed upon a predetermined over travel of the motor piston.

Fig. 6 is a horizontal section on a plane corresponding to the line 6-6 of Fig. 3.

Fig. 7 is an enlarged vertical sectional view on the plane of the section line 1-1 of Fi-g. 1, through the automatic cushion pressure release device. V

Fig. 8 is a similar view showing the cushion release device about to release the cushion pressure.

Fig. 9 is a similar view showing the release of cushion pressure in progress.

Fig. 10 is an enlarged fragmentary section showing a portion of the cushion release mechanism.

Fig. 11 is a horizontal section on the plane of the line II-II of Fig. 10.

Referring to the drawings, it may be noted that a suitable support I, of which but a portion is shown, has pivotally connected thereto at 2 the upper head 3 of a pumping motor which is generally designated 4. Such pumping motor includes, in addition to its upper head 3, a lower head 5, a cylinder 6 having a bore 1, a piston 8 reciprocable in said cylinder bore and having a piston rod 9, and a uid distribution mechanism generally designated I0.

The motor cylinder 6 comprises a portion 6a between whose ends the piston 8 is reciprocable during normal pumping operations, and an aline-d cylinder portion 6b which constitutes a dash pot or cushion cylinder; and a suitable automatic release valve device II, which forms a portion of the subject matter of my co-pending application, Serial Number 102,987, being led concurrently herewith, is arranged to permit breathing of the pumping cylinder during normal pumping operations without the building up of a differential in pressure between the interior and exterior thereof, exceeding 1 or 2 pounds per square inch. Said automatic relief valve ldevice is adapted, however, as more fully explained in my co-pendin-g application, substantially to interrupt the discharge of air from above the motor piston in the event that upward motor piston movement should commence to take place at an excessively rapid rate as, for example, a result of the loss of the pumping load onv said motor, due either to sucker rod line breakage, or to the rupturing of a pump plunger packing, or the like. Obviously, by providing a long enough pump cylinder in the well, it is possible to permit the piston rod 9 to impart to the pump plunger pumping strokes of considerable length during" normal pumping operations, and also to permit further upward movement of the pump plunger without dama-ge to the pump, should a pump packing break-sufficient to enable cushioning and bringing to rest of the motor piston 8.

The distributing valve mechanism IU forms a portion of the subject matter of my co-pending application, Serial Number 102,987, above mentioned. A description thereof in minute detail is, therefore, unnecessary in this case, but a sufcient description is desirable' to enable the mode of operation of the device and its manner of co-operation with some of the auxiliary devices employed therewith to be followed entirely within the confines of this case. The lower motor cylinder head has a projecting portion I5, in which there are formed a fluid supply space I6, a fluid exhaust space I1 and an intermediate space I8 connected through a port I il with the lower end of the cylinder bore 1. Fluid, desirably at pressures of say 200 to 300 pounds per square inch in the case of wells of substantial depth, may be supplied to the space I5 throughfa connection 20, and fluid may be exhausted from the space I1 by way of a connection 2I to a system in which a relatively constant vback pressure of say about 50 to 100 pounds per square inch, depending upon the depth of the well and other factors, may advantageously be maintained. A suitable bore 23 is formed within the projecting portion I5 of the lower cylinder head 5, and receives a liner and valve-chamber-forming member 24, which is appropriately shouldered to position the same against downward longitudinal movement beyond the desired position, in the projecting portion I5 of the cylinder head. An upper head 25 engages the upper end of the member 24 and closes the latter and also serves, together with appropriate clamping'elements 26, to secure the member 24 in the desired position with respect to the lower cylinder head 5. A lower head element 21 is secured in a position to close the lower end of the bore 23, and has a projecting portion 28 of reduced diameter, which fits into an-d closes the lower end of the bore within the element 24. The element 24 has a stepped bore formed therein, the lower, longer portion of which is designated 30 and the upper, shorter and larger portion of which is designated 3I. By the provision of clearance, as at 32, around the lower end of the member 24 and the formation of a passage 33 in the member 21, continuous communication is obtained between the space I1 and the lower end of the distributing valve shortly to be described, and the distributing valve is continuously subjected to motor back pressure.

A. distributing valve 35 is reciprocable within the bore of the member 24 and has an upper, relatively short, larger head 36 fitting the bore 3| and reciprocable therein, an intermediate head 31 spaced from the head 36, and a lower head 39 spaced by a fluid conducting groove 38 from the head 31,' heads 31 and 39 fitting the bore 30.

Since the lower end of the distributing valve is continuously subjected to motor back pressure-a pressure which ranges commonly from 50 to 100 pounds depending upon the installation-it is obvious that reciprocation of the fluid distribution valve may be controlled by effecting variations in the pressure acting upon the upper head of said Valve. So long as pressure acting on said upper head is equal to or greater than the loA 'per' position.

pressure acting upon' .the lower head 39, the uid distribution valve willoccupy a position correspending to that shown inFig. 2.` When, however, the pressure acting upon the upper head of the valve 'm reduced to substantially atmospheric pressure, the fluid distribution valve will be moved upwardly into Va position to effect a 4supply of motor fluid to the lower end of the motor cylinder from the groove I6, through the groove 38 in the valve, through the space I8 and port I9, into the lower end of the cylinder.

Means is provided whereby the movements of the motor piston 8 may control the supply and exhaust of fluid relative to the space above the upper head 36 of the distributing valve, and means controlled by the movements rof the valve itself ,are provided in order that a proper cycle of `operation may be secured. From a point 40 in the cylinder bore 1, uncovered bythe lower end of the upwardly moving piston 8, just as the lat-v ter approximately reaches the desired upper lim, it of its rworking stroke, there is extended a connection 4|, leading to the upper head element 25 of the distributingvalve mechanism. Within this head 25 vthere lis provided a check valve mechanism, so vto speak, 42, comprisinga ported Valve element 43, operative whenin seated position to prevent i'luid passage in either direction between the space above ,the head 36 in the bore 3| `and the bore 1 of the cylinder. Valve 43 is normally maintained seated by a spring 44 and has a projecting stem 45 which is engageable by a hardened plug 46 inthe upper end of the head 36 when the distributing valve 35 is in its top position. Accordingly the valve 43 is unseated and permits communication between the space within the cylinder 6 andthe space within the bore 3| above the valve head 36, when said distributing valve 35 is in its uppermost position. When, however, the distributing valve is in the position shown in Figs. A2 and 3, the valve 43 is seated, and the spring 44 is strong enough to prevent unseating of the valve and passage of iluid from the space above the head 36 to the space within the cylinder bore above the piston 8 even though that space be under only substantially atmospheric pressure, as is the case during no-rmal pumping operations.

The cylinder bore 1 is also connectable, at a considerably lower point, 50, therein, uncovered by the upper end of the piston 8 just about as the latter reaches the desired lower limit of piston travel, with the bore 3| above the head 36, under certain conditions hereinafter described. Tubing 5I connects the point 58 with .a space 52, Within a mechanism 53, hereinafter more fully described, andr tubing 54 leads from mechanism 53 to a. valve-seat-providing tubular element 55 secured centrally in the head 25. Member 55 provides `a valve seat 56, and the head 36 of the distributing valve carries a resiliently positioned valve elementv 51, which, in the upper position of the distributing valve, engages the seat 56 and prevents flow in either direction 'between the space within the bore 3| above the head 36 of the distributing valve and the point of communication 58 with the cylinder bore 1. No pressure normally present in the cylinder bore 1 can unseat the valve 51`when the distributing valve is in its up- However, when the distributing valve isfmoved to a position to move the valve portion51 out of engagement with seat 56, free communication `between the cylinder bore at 7W point 58 therein and the top of bore 3l is established.

' The mode of operation of the device so far described is self-evident. Assume that the parts are all in the position illustrated in Figs. 2 and 3, and it will be clear that the motor piston 8 is still upon its downward pass and has not yet uncovered the point 58 for a suii'iciently long period, at least, for the iluid to exhaust to atmosphere from the bore 3| above the Valve head 36, and allow back pressure acting upon the lower end of head 39 of distributing valve 35 to raise the lat.- ter to fluid admission eiecting position. It will be obvious that in the instantaneous position of the parts shown in Figs. 2 and 3, the space above the head 36 is subject to the same pressure that is acting ony the lower end of the head 39, for the lower end of the motor cylinder is connected to exhaust, that is to the back pressure against which the motor exhausts, and that same back pressure prevails in the space below the head 39. When the top of the motor piston 8 passes below the connection point 58, the i'luid within the bore 3| above the head 36 of the distributing valve will pass through the connections 54, 52 and 5| into the motor cylinder above the motor piston, and there pass to atmosphere since the space above the motor piston is normally substantially at atmospheric pressure, due to the presence of the relief device I|. As soon as the pressure above the valve head 36 has been released, the constant pressure acting on the lower head 33 thereof will raise the distributing valve, and the groove 38 in the latter will move from exhaustestablishing position to admission-effecting position, and motive fluid will be supplied from groove I6 to groove I8 and then through port i9 into the space beneath the piston 8. Obviously, as shown in the drawings, the member 24 must be provided with suitable passages connecting its interior with the several spaces |6, I1 and I8. Upon admission of motive fluid beneath the motor piston the latter commences its upward travel, and when its lower end passes above the connection point 50, cylinder pressure cannot pass to the space above the head 36 of the distributing valve and cause downward movement of the latter, because the valve 51 engages the valve seat 56 and seals oi communication between the cylinder bore and the distributing valve chamber bore. The motor piston accordingly continues its upward travel until it passes above the connection point 40, at which time iiuid will be enabled to pass through the connection 4| and the then unseated valve 43 to act upon the upper head of the distributing valve and start the latter towards exhaust-effecting position. The pressure passing the valve 43 merely starts the distributing valve upon its downward movement, and the complete throwing movement is effected by pressure which passes from the connection point 50 to the space above the distributing valve as soon as valve 51 moves oi the valve seat 56. As soon as the distributing valve assumes the position shown in Fig. 2, release occurs, and the motor piston, under its own weight and that of the supported parts, begins to move downwardly. The downwardly moving motor piston first passes below the connection point 40, and as the space above the motor piston is approximately at atmospheric pressure, the pressure holding the distributing valve in its lower position would be vented were it not for the fact that the valve 43 is engaging its seat and is not unseated by the pressure diierential at its opposite sides, the spring 44V being strong enough to prevent this occurring. ,'-Ihe motor piston therefore continues its downward movement until its'upper end passes beneath the connection point 56, at which time the pressure which has been holding the distributing valve in its lower position will be vented to atmosphere through the valve seat 56, connection 54, space 52, connection 5|, the cylinder bore, and the relief device The distributing valve will then again be moved into admission effecting position by the fluid pressure acting upon its lower end from the back pressure line, and another cycle like that which has been described will be started.

As previously pointed out, it is desirable to shut down the motor in the event of sucker rod line breakage or the blowing through of the pump packing, and, therefore, means is provided for accomplishing this function. Such means may take the form shown in Letters Patent No. 2,064,- 145, which patent shows means` for closing they admission and the exhaust lines to the pumping motor, or may assume the form shown in my copending application, Serial Number 102,989, led concurrently herewith. For purposes of illustration I am here showing the latter mechanism and will describe its mode of operation.

Obviously, if the rod line broke during the upstroke of the motor piston 8, which is evidently the time when such a breakage would occur, if at all, the motor piston 8 would be freed ofr a substantial part of its load. The pressureacting beneath the motor piston, which is so determined as to provide for the desired speed of upward movement of the motor piston under full load, would obviously be much in excess of that necessary to raise the piston under the then reduced load condition. Therefore, the motor piston would move upward at a much accelerated rate and would pass its normal upward limit of travel, notwithstanding the fact that the condition for release of the working fluid beneath it would be produced as soon as the upward movement of the piston carried it above connection point 40. The motor piston 8 would, therefore, pass up into the cylinder portion 6b and would there be cushioned, building up above it a considerable cushion pressure before it would come to rest. A downward movement of the motor piston would then be initiated, and the piston would move downward to its lower position and then again move up under the admission of line pressure, effected by the reversal of position of the distributing valve as the motor piston approached bottom position, unless some means were provided to interrupt the operation of the motor.- Serious damage might be done by an excessively rapid downward movement of the motor piston during even a single stroke, unless means were provided to reduc'e quickly the cushion pressure or otherwise retard downward movement of the motor piston, and after describing theV structure which is` employed for the purpose of stopping the motor, I shall describe the improved means which I am disclosing herein for the purpose of reducing the cushion pressure as soon as the motor piston has come to rest and begun to descend.

The means for interrupting ope-ration of the distributing valve 35 and holding the latter in exhaust-establishing.position as soon as abnormal operation of the motor begins to take place, includes the device 53 heretofore mentioned, and certain connections which I shall now explain. An additional connection point 6!) with the cylinder bore will be provided atsuch a point that it will be `uncovered by the lower end of the up- Wardly moving pistonS, only when the,latigerv makes 'such an extended upstroke as will never occur except in the event of such a derangement as breakage of the sucker rod line or the blowing out of packings on the pump plunger. This connection point will be connected by a suitable tube 6| with a space 62, the supplying of fluid to which will render the automatic shut-down device 53 effective. The shut-down device 53 cornprises a valve casing 64 provided with alined bores 65 and 66, of which the latter is somewhat the larger and also the upper one. A conical or other suitably formed seat 61 is located at the junction of the bores 65 and 66. Connection 5| enters the bore 65 near the upper end of the latter, and connection 54 communicates with the bore 65 at a point somewhat below the point of communication of the connection 5| with the bore 65. These points of communication are respectively designated herein 68 and 69. A valve element 10 is reciprocably mounted in the bores 65 and 66, and comprises a lower head 'Il tting the bore 65 and an upper head 'i2 tting the bore 66; and a conical portion 'I3 adapted to co-operate with the seat 61 is provided, and also a reduced portion I4 cut away as at 'l5 to leave the space 52 hereinabove mentioned. Within the bore 66 there is arranged the lower head 1'.' of a manually operable plunger element '18, whose stem portion 'I9 passes through an opening in the upper head 8|, which closes the top of the bore 66. A manual pressureapplying portion 82 is secured upon the stem 19. A spring 84 is arranged between the enlarged portion 'l2 of the valve element 'l0 and the head l'. A latch device 86 is movable between the positions shown respectively in Figs. 4 and 5, and normally holds the head 11 in such a position that the spring 84 will hold the valve l@ in the position shown in Fig. 4, notwithstanding the pressure which may act upon the lower end of the head H thereof. A piston 88, reciprocablc in a bore 89 formed in the member 64, is movable upon the supply of pressure through the connection 6|, to withdraw the latch 86 and release the plunger element 18 for upward movement, thereby relieving the valve 10 of the holding pressure exerted by the spring 84. Connection 6| communicates at with the space 62 formed within the cylinder bore 89, to the inside of the piston 88; and a connection 9| leading to the live pressure space I6 in the valve chest opens into the bore 65 below the valve head 1|. Obviously any other means of effecting throwing supply to the valve head 1| might be employed. A connection even with the back pressure line of the pump, having in mind the large size of the head 36 of the distributing valve, would, of course, provide a sufficient pressure to effect the desired operation.

The mode of operation of the apparatus last described may be now readily followed. In the normal position of the controlling device 53, the parts will occupy the positions shown in Fig. 4, the valve element 'lll being in its lower position with the portion 13 thereof seated on the seat 61, and the space 52 surrounding the reduced portion `'14 of the valve 10, establishing communication between the ports 68 and 69, and the head 1| preventing the flow of line pressure through the connection 9|. Assume now that the rod line breaks and that the motor piston rapidlyv moves upwardly in an extended stroke and passesk above the lconnection point 60. The pressure from beneath `the motor piston 8, even though it mayhave begun to drop as a result of 75 the `over travel ofthe motor piston, will still be kentirely adequate, upon passagev through the of what occurs when the head 11 isunlatched.

The live pressure acting upon the'lower end of the valve headf1| immediately moves the valve 10 up to the position where the head 1| will seal port 6,8 and will uncover port 69. The live uid from'the space I6 will then immediately pass through 9|, through the bore65 to the Aport 68, through the connection 54 and the element 55,

and through the valveseat'56, into the bore 3| .above the upper end of. the distributing valve 35, `and hold the latter firmly in lits exhaustestablishing position,or moveit thereto if it has not yet attained such position, and nothing can thereafter move said distributing valve out of its position until the valve 10 is again returned to its position shown in Fig. 4. Fig. 5 showsthe parts in the positions they assume after the upwardly moving piston 8 has uncovered the connection point 60. All that is necessary to enable the motor to resume operation, when this is desired, is for the operator to apply pressure to the portion 82, force the plunger 18 downward, move the latch 86 in, and so hold head 11 in the position shown in Fig. 4; and the valve 10, which will have been moved down into its position shown in Fig. 4, Will there be maintained, and the operation of the motor can then be started in its normal manner.,

Now to return to the apparatus for' preventing an unduly rapid downward movement of the motor piston and the attached parts, as a result of a building up of a comparatively high cushion pressure during the over-travel of the motor pistonin an upward direction. In order that the relatively high pressure so produced shall not continue to exert a pressure on the top of the motor piston and imparty to the latter a high downward velocity, I have provided improved means for relieving the cushion pressure asr soon as the same has begunto drop due toa reversal of movement of the motor piston.` Obviously, if such a control werer made merelyl responsive to the creation of a predetermined maximum pressure Within the cushion cylinder, itfwould'be possible that venting might occur prior'to the bringing to rest of the piston, and accordingly I prefer to employ a construction inv which the relief of the cushion pressure shall be delayed until the motor piston has been brought fully to rest and reverses its motion and begins to move downward, with a resultant slight reduction in the cushion chamber pressure. Because of the peculiar nature of the expansion and compressionof air, it will bey evident thatv with a relatively high cushion pressure a very small movement of the motor pistonin the downward direction may make a substantial reduction in the pressure within the cushion space, and accordingly the use of this reduced pressure condition will enable a certainty of actionv and at the same time not permit the imparting by the built-up cushion pressure of a high velocity to the downwardly moving motorV piston.

For the purpose of effecting the desired control, I provide means continuously subject to the pressureconditions within the cushion space of the motor cylinder, and adapted to store up energy in the event of the building up of an excess pressure in said cushion space, and to employ said energy upon a reduction in pressure within said cushion space for the purpose of opening vent means leading from said cushion space to the atmosphere or to some other point of low pressure discharge.

Now referring more particularly to Figs. l to ll inclusive on the drawings, the uppermost portion of the cylinder bore 1 within the part 6b of the motorcylinder will be observed to be connected through a suitable connecting and support device with an apparatus which is generallyV designated |0|. This apparatus contains a chamber |02 connected by a passage |03 in the connecting element |00 with the top of the cylinder bore 1; and said space |02 has continuous communication through a port |04 with an elongated fluid reservoir |05, which extends from the top of the device |0| to the bottom of the latter. Apparatus |0| includes a main body porvtion |06, a top closure element |01, and a lower head element |08, all suitably connected together; and the portion |06 includes not only the reservoir space but a larger, parallel chamber ||0. Extending upwardly within the chamber ||0 and supported by the lower head |08 is a cylindrical element I, whose upper end carries an outwardly-opening spring-pressed check valve ||2 controlling the communication between a passage ||3, which is in continuous communication itself with the fluid reservoir |05, and a space above the end of the cylindrical element Surrounding the member and slidable longitudinally with respect thereto is a hollow spring support member ||4 providing a peripheral ledge upon which the lower end or a spring I5 res-ts. The member ||4 is closed at its top, so that its interior I6 constitutes a cylinder bore coacting with the stationary piston, so to speak, The upper end of the spring ||5 engages an abutment member ||1, which contacts the lower end of the stem ||8 of a valve H9, which controls the communication between the space 02 and a space |20 which is in constant communication with the atmosphere through a series of openings |2|. 'I'he valve ||9 is adapted to co-operate with a seat |22 surrounding a passage |23, which when uncovered by said valve H9, connects the chamber |02 freely with the space |28. 'I'he upperA head |01 contains a spring |24 acting upon the top of the valve element H9, and also provides a guide |25 for a reduced cylindrical portion |26 integral herein with the valve H9. The space |05 is desirably filled substantially full with a liquid such as a light oil or the like, and the seat of the valve ||2 may be scored or grooved if desired to permit an automatic restoration of the device to working condition after a predetermined period. Since, however, it is important that this device shall be capable of functioning prior to the putting in operation again of the pumping motor, it is as well to omit any means for providing an indefinitely prompt return to operative condition, as serious injury might result were the motor to be restarted with the cushion device inoperative, as it would be if the valve ||9 were still unseated.

,Now the mode of operation of this apparatus will be readily understood. During the normal reciprocation of the motor piston 8 within the cylinder bore 1, the release device H will cause a breathing action to take place, and the differential between atmospheric pressure and the pres'- sure within the space Within .the cylinder bore'I, will not exceed one or two pounds per square inch. When, however, the sucker rod line breaks, should that occur, or a pump plunger packing ruptures, the motor piston 8 will move rapidly upward past the mouth of the release device H, and trap fluid in the upper end of the cylinder bore 1, and compress that Huid to a considerable pressure in the course of decelerating. The pressure built up within the bore 'I will pass through the connection |03 into the chamber |02, through the passage |04, and act upon the top of the liquid within the reservoir |05 and force said liquid through the passage H3 and past the valve ||2 and raise the slidable spring seat cylinder element I I 4 upwardly, and place the f spring |5 under compression.` vThe valve H9 will be formed with an upper area relatively larger than the cross section of the bore of the member H4, and because the pressure acting upon the top of the valve H9 and the pressure acting within the bore I I6 will be substantially the same, there will be no effective tendency towards unseating the valve H9 so long as the pressure within the cushion space in the cylinder bore 'I remains unreduced. When the motor piston 8 has come to a stop and begins to movedownward, and there is an increase in volume within the space above the piston 8 within the cylinder bore '1, there will be a reduction in pressure Within that space. However, the check valve H2 will not permit reverse flow of the liquid which has entered and been trapped in space H6 above the top of the member H I, so there will be no reduction of 'compression of the spring H5 by lowering of member I I4 as the pressure drops within the top of the cushion space. Therefore, a reduction in the pressure acting upon the top of the valve H9, will shortly permit the latter to be unseated by the force exerted by the spring I I5, and thereupon the pressure within the upper end of the cushion space in the cylinder bore 'I will be quickly reduced to atmospheric pressure, passing through the passage |03, space |02, port |23, and passages 2|, to the atmosphere. After the motor has been shut down the pressure may gradually leak out of the bore H6 above the stationary piston-like element and the parts graduallyassume once more Athe position shown in Fig. '7. Figs. 7, 8, and 9 are interesting in disclosing the mode of operation of this device, in that Fig. 7 indicates the position of the parts during the normal pumping operation, that is, at such times as there is no building up of any substantial pressure within the cushion spa'ce in the bore Fig. 8 illustrates the position of the parts assumed when the motor piston has made a rapid and overlong stroke as the result, say, of the breaking of the sucker rod line. Here it will be noted that fluid has been driven down in the reservoir |05, up past the check valve H2, and trapped in bore H6 above the member III. Because the pressure is still at its maximum value within the space |02, the valve H9, however, remains upon its seat. Fig. 9 shows the condition when the cushion pressure has been permitted to lower as a result of a certain amount of 1re-expansion after the motor piston 8 starts its downward'travel. Here it will be observed that the lowered pressure acting upon the top of the valve H9 has permitted that valve to unseat under the pressure of the spring VH5 and to vent to atmosphere the pressure within the cushion space. i

From the foregoing description, it will be ob! vious that I have provided an improved apparatus for cushioning the piston of a pump operating motor in the event of loss of load thereby, and a relieving of the cushion pressure prior to th possibility of the imparting to the piston of a dangerous velocity in an opposite direction. It will further be noted that I have provided an improved motor in which, when through breakage of certain parts, the motor is relieved of its load, the over-travel of the motor piston is duly cushioned 'and the piston brought to rest and then prevented from obtaining an unduly rapid opposite velocity, and the motor is simultaneously, or practically so, shut down, so that the entire system-is put out of operation, after having been brought harmlessly to rest; and the system is maintained shut down until such time as an operator can give it his attention. It will be obvious 'that the structure provided for controlling the reduction automatically in the cushion pressure is simple, positive in action, certain in operation and comparatively inexpensive in construction. Further I have provided an improved cushion device per se.

While in the accompanying drawings I have disclosed and in the foregoing specification described one species which my invention may assume in practice, it will be understood that the same may be modied and incorporated in various other embodiments without departing from the spirit of the invention or the scope of the appended claims.

What I claim and desire to secure by Letters Patent is:

l. In combination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocable therein, and means for eifecting supply of motive fluid to one end of said cylinder and the exhaust of fluid therefrom after the same has Worked in said cylinder, and means associated with the normally inactive end of said motor cylinder for building up a cushion pressure for cushioning over travel of said motor piston should the same occur and venting the cushion pressure upon a reverse movement' of said motor piston.

2. Incombination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocabletherein, and means for effecting supply of motivefluid to one end of said cylinder and the exhaustv of iiuid therefrom after the same has worked in said cylinder, and means associated With'thenormallyinactive end of said motor cylinder for building up a cushion pressure for cushioning over travel of said motor piston should the same occur and venting the cushion pressure upon initiation of reverse movement of said motor piston.

3. In combination, in a cushion apparatus, a cylinder, a piston movable into said cylinder to build up a cushion pressure, means associated with the end of said cylinder towards which said piston moves and subjected to the pressure conditions therein for placing an energy-storing means in a stressed condition as cushion pressure is built up in said cylinder, and means operable upon a reduction in the cushion pressure within said cylinder, and actuated by said energy-storing means, for venting pressure from said cylinder upon an initial drop in pressure therein.

4. In combination, in a cushion apparatus, a cylinder, a piston movable into said cylinder to build u p a Cushion pressure, means associated "itv with the end cfsaid cylinder towards-which said pistonl moves and: subjected' to the pressure con ditions therein for hydraulically placing an en ergy-storing mea-ns in astressed condition as I vpressure is built up in said cylinder, and means operabl'eupon av reduction inV the pressure within saidcyl-inder, and actuated by said' energy-storing means, for venting pressure from said cylinder upon aniinitial dropfin pressure. therein.

5. In4 a device' of 'the character described, in combination, a casing having al chamber therein connectable tea space, the pressure in which is tol be controlled?, another space in communication with the atmosphere; a" valve` controlling communications between saidr spaces, and means operableto open said valve upc-n-V a pressure drop insaidl first mentioned spacev below the maximum value esa-blished4 the latter including any energy lstoring device and mea-ns operable5 by pressure transmittedto said rst mentioned space for storingy ei-rergyJin` said device:

6: In combination, in1 a controlling apparatus for a cushioning-device, means: providing a plurality of Vchambers one connectable with a cushion space and another'connectcd with the'atmosphere, avalve'controlling communication between sai'd chambers, a spring' operative under certain conditions-to exert an opening force on said valve, means operable' byA pressure fromv said first mentioned chamber for stressing said vspring and maintaining the sarnej stressed irrespective of a later` reduction infr pressure withinsaid first named cham-ber', sai'dlast mentioned means operable when pressure conditionsfbuildf up in said cushions space above apredetermined?- desired maximum,Y said valve subject to the pressure conditionswithin salidiirst'named chamber and held by said conditions in closed position until after the pressure acting thereon falls below the maximum attained value by a predetermined amount.

7. In a cushion cylinder controlling apparatus, incombination, a casing having a chamber communicable with a cushion space, said casing further having a chamber therein communicating with the atmosphere, a valve normally maintained closed and subjected to chamber pressure conditions for normally precluding communication between said chambers, and means energized .by pressure transmitted to said first named chamber while said value is closed for creating a pressure acting on said valve in a valve opening direction and maintaining said pressure despite pressure reduction in said first named chamber.

8. A cushion cylinder, a piston movable in said cushion cylinder, a vent valve for said cushion cylinder subjected to the pressure conditions in the latter in a direction tending to maintain said valve seated, and means operable by pressure conditions created in said cushion cylinder during the cushioning function thereof for creating, while said valve is closed, a valve opening pressure applicable to said valve with undiminished force when said cushion cylinder pressure diminishes, whereby said valve opens upon a falling of! in cushion cylinder pressure.

9. In combination, a pumping motor having a pumping load, and including fluid distribution means, and means automatically operative in the event of loss of motor load for locking the fluid distribution means for said motor in exhaust establishing position, and cushioning means for checking the motion of said motor in the event of the loss of load thereby and after cushioning of the motion of said motor automatically relieving the cushion pressure prior to the establishment' thereby of a high motor velocity in a reverse direction.

lfO. In combination, a pumping motor adapted toraise a. pumping loadV and including a cylinder and a piston reciprocable. in said cylinder and a distributing.' valve for selectively admitting pressure4 to said-cylinder to effect upward movement of the piston in said cylinder and releasing the pressure from said cylinder for the purpose of causing` downward movement of said piston,

automatically operative, and controlled by pressure conditions in said cylinder resultingwhen the'motor piston makes a stroke of a length exceeding a predetermined value, for automatically maintaining said fiuid distribution valve in exhaust' effecting position, and means controlled by suchconditions above said motor piston in said cylinder for creating a cushion pressure and automaticallyf venting the same after cushioning isV completed and prior to substantial downward movement of said piston.

` Il. Inv combination, in a pumping apparatus, a pump operating motor having a vertical cylinder with a piston reciprocable therein and uid distribution means operative automatically a1- t'erna-tely' to admit pressure fluid beneath said motor pistonk and. to vent pressure fluid from beneath the same, means operable by pressure from beneath said motor piston when the latter makes a stroke exceeding by 'a predetermined amount the normal operating stroke for locking said fluid distribution means in exhaustestablishingV position, and means governed by pressure conditions in said' motor cylinder above saidpiston for sealing the upper end of said cyiinder during cushioning occurring in the event .of an unduly long motor stroke and for releasing said cushioning pressure to atmosphere in response to a drop in pressure above said motor piston prior to the attainment by said piston of a substantial velocity in a downward direction.

12. In a dash-pot, a cushioning device operative on performing its cushioning function to produce conditions conducive to a back kick by the same, and means for preventing a back kick by the same including means for relieving cushion pressure on motion in the reverse direction of the device to be cushioned.

13. In combination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocable therein, and means for effecting supply of motive fluid to one end of said cylinder and the exhaust of fluid therefrom after the same has worked in said cylinder, energy-storing means for opposing a progressively increasing resistance to piston movement as overtravel thereof in the working direction occurs, and means for releasing the stored energy early in the movement of the piston in a reverse direction following the bringing of the same to rest.

14. In combination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocable therein, and means for effecting supply of motive fluid to one end of said cylinder and the exhaust of fluid therefrom after the same has worked in said cylinder, elastic energystoring means for opposing a progressively increasing resistance to piston movement as overtravel thereof in the working direction occurs, and means for releasing the stored energy early in the movement of the piston in a reverse direction following the bringing of the same to rest.

15. In combination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocable therein, and means for effecting supply of motive uid to one end of said cylinder and the exhaust of fluid therefrom after the same has Worked in said cylinder, energy-storing means including a body of compressible gas and means for progressively compressing the same for opposing a progressively increasing resistance to piston movement as overtravel thereof in the Working direction occurs, and means for releasing the stored energy early in the movement of the piston in a reverse direction following the bringing of the same to rest.

16. In combination, a single-acting expansiblechamber motor comprising a cylinder, a piston reciprocable therein, and means for effecting supply of motive uid to one' end of saidl cylinder and the exhaust of fluid therefrom after the same has Worked in said cylinder, and energystoring and releasing means both governed by piston movement for opposing a progressively increasing resistance to piston movement as overtravel thereof in the working direction occurs and for releasing the stored energy promptly upon a reversal of piston movement following the bringing of the same to rest.

17. In combination, a pumping motor having a pumping load and including fluid distribution means, means automatically operative in the event of loss of motor load for causing the motor to be connected to exhaust, means for cushioning the resultant travel at a higher speed which follows loss of load, and means for precluding the return to the piston of the energy absorbed in the cushioning thereof.

18. In combination, a pumping motor having a means, means automatically operative in the event of loss of motor load for shutting down the motor, means for decelerating the piston following loss of motor load, and means for precluding the return to the piston of the energy absorbed in the deceleration thereof.

19. In combination, in a motor, a cylinder, a piston reciprocable therein, means for applying pressure to one end of saidvpiston to cause it to make a working stroke, and means for removing pressure therefrom after said piston has completed its Working stroke, means creating a force opposing movement of said piston beyond its Working stroke, and means removing said opposing force upon the occurrence of any decrease in said opposing force.

20. In a motor of the character described, the combination of relatively reciprocable cylinder and piston elements, fluid distribution means for supplying pressure uid to and exhausting fluid from said cylinder element for effecting relative reciprocation of said elements, means inactive during normal operation of the motor and automatically operative in the event of sudden loss of motor load for providing a relatively high cushioning pressure at one end of said cylinder element to check excessive relative movement of said elements in one direction, means automatically operative upon occurrence of abnormal motor operation for automatically rendering said luid distribution means inactive thereby to shut down the motor, and means operative subsequently to said cushioning action and when such excessive relative movement of said elements in said direction is checked for automatically relieving the cushioning pressure.

WADE H. WINEMAN.

CERTIFICATE OF CORRECTION. Patent No. 2,159,LL67. May 25, l959 Y WADE H. WINEMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page l, first column, line )41, after the word "motor insert piston; page 5, second column, line l5, for "drawings" read drawing; page 7, first column, line 18, claim 5, for "esablished" read established; line 50, claim Y, for the word "value" read Valve; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 25th day of July, A. D'. 1959.

Henry Van Arsdale, v (Seal) 'Acting Commissioner of Patents.

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