US2947144A - Pneumatic hydraulic pumping apparatus - Google Patents

Pneumatic hydraulic pumping apparatus Download PDF

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US2947144A
US2947144A US67880757A US2947144A US 2947144 A US2947144 A US 2947144A US 67880757 A US67880757 A US 67880757A US 2947144 A US2947144 A US 2947144A
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pressure
pump
rod
reservoir
valve
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Samuel V Smith
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PNEU HY CO
PNEU-HY Co
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PNEU HY CO
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04BPOSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B47/00Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps
    • F04B47/02Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level
    • F04B47/04Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps the driving mechanisms being situated at ground level the driving means incorporating fluid means
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00Fluid handling
    • Y10T137/2931Diverse fluid containing pressure systems
    • Y10T137/3115Gas pressure storage over or displacement of liquid
    • Y10T137/3127With gas maintenance or application

Description

Aug. 2, 1960 s. v. SMITH 2,947,144
PNEUMATIC HYDRAULIC PUMPING APPARATUS i Filed Aug. 19, 1957 3 Sheets-Sheet l n" JAMUEL I/'M/TH INVENTOR.
n 1MM/wf Aug. 2, 1960 s. v. SMITH 2,947,144
PNEUMATIC HYDRAULIC PUMPING APPARATUS i Filed Aug. 19, 1957 3 Sheets-Sheet 2 'g. a 7: /g. 5. 5
Je" I JAM/Ez. HJM/TH [Z4/SE1 INVENTOR.
l ff BY M t:
f7 fram/Ey Aug. 2, 1960 s. v. SMITH 2,947,144
PNEUMATIC HYDRAULIC PUMPING APPARATUS Filed Aug. 19, 1957 5 Sheets-Sheet 3 F/g.4. fr
AMI/EL 1./ J'M/ TH INVENTOR.
rrORA/EY access to .the well ,for :servicing purposes.
2,947,144v Y PNEUMATIC HYDRAULIC PUMPING APPARATUS Samuel V. Smith, Long Beach, Calif., assgnor to Pneu- Ely Co., LongBeach, Calif., a corporation of Caliomra t Filed Aug. 19, 1957, seri. No. :678,807 1o Claims. (icl. ntl-"52) This invention relates generally to apparatus used for pumping wells, and more particularly has to do with improvements in .Huid pressure powered pump jacks operable to raise and lower well pump rods and the like.
In general fluid pressurized pump jacking units presently in use are characterized as regards their construction in relation to the well head as extending to a considerable height above the ground and over the well, it being conventional practice to mount a large pumping assembly vertically ,over the pump rod for supporting the latter and for reciprocating it up and down. However, at the present time there is increasing public and civic expression of .a need for restricting the observable size of such equipment, particularly in residential areas where the benefits ofl petroleum production are recognized and sought after at the expense of accommodating to the necessary presence ofthe production machinery.
Accordingly, it is a Vmajor object of the present invention to substantially limprove the construction and especially the arrangementof well pump jacking units so as to .minimize the apparent size thereof to the observer, while ,at the same time increasing the reliability and improvinglthe operation -of the equipment. To this `end, the invention contemplates the provision of apparatus for vertically reciprocating a well pump rod or .the like projecting above ground surface level, comprising a plurality of vertical .cylinders spaced apart laterally so that they may besunk downwardly into the ground in laterally offset relationto the well, together with pistons ,reciprocable up and down in the cylinders and means for supporting the pump rod atY its ,projection .above yground by the pistons and for reciprocating the `supported rod up and down in response ,to piston reciprocation. Ihe pistons are then reciprocable below groundsurfacelevel rby application of fluidpressure to them in ,the manner .to be explained, so that alarge part of the equipment needed to lift `and lower ,the pump vrod is ,underground .and out of sight of the observer. Also, there lis a VYof jacking equipment over the well head itself, facilitating ready The ground surface level referred to will be understood to meanthe surface immediately around the well head, so that the surface may comprise the `bottom of a-,shallow open pit into Iwhich all of the `equipment is received.
In the carrying out `of the invention to Suit vthe purpose described, the pistons and cylinders 'are preferably ,laterally .spaced on opposite sides of a center corresponding to the well location, so that an aboveground .cross head structure interconnectingthe pistonrods may ,bridge over the well pump rod for reciprocating ithe latter as the pistons are ,displacednp Land down in thelcylinders. Such displacement is yeffected by means interruptedly cornmunicating `hydraulic pressure,` for example, -toatirstpair of jacking tpistons n. opposi te fsides rof the *well `and tending interruptedlgyttoraise `the,p tnnprod, :and also.by. means constantlyrcommuuicating gas pressurevtoasecondpair of balance ,pistons likewsespaced onopposite `sidesof the Well and underground, tending constantly to raise the arent pump rod. When, as contemplated, the pressure communicated to the balance pistons is insufcient alone to raise the pump rod, thelattcr is lifted only during communication of hydraulic pressure to the-'jacking pistons, interruption of such communication allowing the pistons to drop on the pump rod downstroke, the rate of drop being controlled by restricting` the backflow of hydraulic uid pushed from the Vcylinders by the pistons, as will be explained.
Another major object of the invention concerns the provision of valve means responsive to reciprocation of the pistons for controlling interruption of hydraulic uid pressure communication to the pistons, the valve placing pump discharged vhydraulic fluid in communication with the jacking pistons on the pump rod upstroke, and placing fluid backfiow therefrom in communication with the pump intake during the pump rod downstroke, the net effect of the latter being to brake and thereby control the dropping rate ofthe pump rod. At this time, the pump discharge is placed in communication with the balance pistons so that the pump then discharges against the gas pressure constantly Vcommunicated rto the balance pistons. i
Other .additional objects of the invention include the provision of means for maintaining a predetermined pressure differential between the pressure exerted on the hydraulic fluid by the jacking pistons under the weight of the pump |rod load, andthe gas pressure communicated from a gas reservoir to the balance pistons via hydraulic liquid, so that as the load increases` or decreases, the balance pressure may likewise increase or decrease to balance the load and thereby permit the hydraulic fluid pump to operate lfor effectively lifting the-pump rod in the well.
These and other vfeatures and objects of the invention, as Well as the details of an illustrative embodiment, will be more fully understood from the following detailed description of the drawings, in which:`
'Fig 1 is a general view showing in .elevation the pumping apparatus and its relation to the well head;
Fig. 2 is a plan view of the Fig. r1 apparatus;
Fig. 3 is an enlarged vertical Vsection taken through actuating mechanism for the pilot valve; v j
Fig. 4 is an enlarged View taken in section through a part of the Fig. 3 mechanism, the pilot valve and master valve, showing how these operate with relation to one another;
Fig. 5 is a partial kplan view of Fig. 1 v,showing mechanism used to regulate the gas pressure in a reservoir;
IFig. 6 is a section taken through actuating mechanism usedfor comparing reservoir gas pressureexerted lo n the balance pistons and hydraulic iluid pressure exerted .on the jacking pistons; and
Fig. 7 is a section taken through the lower portion of the gas reservoir illustrating the manner in Vwhichsystem -luid is cooled.
Referring to the apparatus as shown in jF-igs.' 1 `and 2 and generally indicated at 10, the `latter includes a pair of balance cylinders 11 extending vertically and laterally spaced on opposite sides of an underground well casing 142, indicated in broken lines, andanother pair of jacking cylinders 13 also spaced on opposite sides of the casing, and extending vertically underground. The various cylinders may be supported on concrete as indicated at 1 4, or merely by the formation itself where the structure thereof is sufficient to support'the loads involved. Also, the cylinders Aare :interconnected by a steel ring `shown at 15 below the ground surface level 16, thering Apreferably being connected to the casing l12 so that .jacking Iand Abalance loads may be transferred from the pistons and ,cylinders tothe casina The lower ends of all the cylinders 11 and 13 are closed as by means of steel plugs 17, While their upper ends are internally threaded for receiving cylinder heads 18 projecting above the ground level 16. The top surfaces of the heads serve to stop downward travel of enlarged piston rods 19, the lower and relatively smaller end portions 20 of which are secured within tubular balance pistons 21 and jacking pistons 22, these latter being guided for up .and down reciprocation by the cylinder heads 18. Suitable packing material 23 seals olf between the pistons 21 and 22 and the cylinder heads so as to maintain hydraulic pressure within the spaces between the pistons and the cylinders during-their reciprocation. j
The extensions 19 of the jacking and balance pistons projecting above ground surface level 16 are interconnected byV a cross head structure25 shown in Figs. 1 and 2 and including transversely extending arms Z6 interconnecting the opposite extensions 19 and extending over the well head 27 and supporting a central pump rod 28, which is received downward within the casing 12. A suitable interconnection between the cross head 25 and rod 28 may be a conventional keeper indicated at 29 into which a locking bolt 30 is threaded for securing the keeper to the rod 28.
Speaking generally with respect to :dow of fluid and liquid to and from the jacking and balance cylinders, Figs. l and 2 show that hydraulic liuid is conducted to and from jacking cylinders 13 via lines 33 branching from common line 34, while liquid under pressure is conducted to and from the balance cylinders via conduits 35 branching from a common conduit 36, both the lines and the conduits described opening into the cylinders underground. While reference in different portionsof this description will be made to hydraulic iluid and also to hydraulic liquid, it will be understood that these terms refer to a common hydraulic liquid or fluid, the distinction in terminology being merely for purposes of claritica-tion as regards association of liquid with pressure communication to the balance pistons, and ,uid as concerns pressure communication to the jacking pistons.
'Further in this respect, the common source of the hydraulic liquid or uid is in the bottom portion 37 of a reservoir tank 38, and its upper level upon which gas pressure in the reservoir is exerted iiuctuates between the broken lines indicated at 39 and 40 in Fig. l, associated with the extreme downstroke and upstroke positions of the pistons respectively. Gas pressure in the reservoir is constantly communicated to the balance pistons via the liquid in the bottom portion 37 of the reservoir, and the liquid in the conduits 41, 36 and 35, conduit 41 shown in broken lines in Fig. l opening into the bottom portion of the reservoir. 4It will be understood that this balance pressure exerted on the pistons 11 and tending to raise them togetherV withV the pumping `rod is insufficient to accomplish such lifting to a degree which may be overcome by the application of hydraulic fluid pressure to the jacking pistons 13, as will be described, the total pressure then being suicient to lift the pump rod and the string attached thereto in the well. However, upon interruption of hydraulic iiuid pressure communication to the jacking pistons, the pump rod 28 and the supporting pistons will drop, such lowering being interrupted before the piston extensions 19 strike the cylinder heads 18.
The above described rather small pressure differential needed to effect raising of the well pump rod and supporting pistons is supplied by the pump 42 shown in Figs. l and 2 having its pressure fluid discharge 43 connected through a master valve 44 with lines 33 leading to the jacking pistons during the upstroke, and having its inlet 45 in liuid pressure receiving communication with jacking cylinders via lines 33, 34 and the master valve 44 during the downstroke movement of the pistons and pump rod. Briefly, in regard to the latter condition and V42 is preferably used to meter fluid backow from the jacking cylinders to thel reservoir during the piston downstroke, the constant speed pump regulating the downstroke speed so that the latter is constant regardless of pressure or vacuum conditions of uid under the jack pistons and hence at the pump inlet.
Coming now to a description of the master valve 44 referred to in connection with Figs. l and 2, it is shown in detail in Fig. 4 to comprise an elongated housing 48 having a bore 49. The latter receives a pair of like plugs Si), preferably cast iron, received endwise oppositely in the bore, the plugs having llanges 51 connected with housing anges 52 by means of bolts 53. The plugs in turn contain axially aligned bores 54 receiving an elongated valve spool assembly 5S which includes an axial shaft 56 mounting spools or pistons 57 at opposite ends of the shafts, and intermediate spools or pistons 58, the entire spool assembly being shown in its extreme leftward position in Fig. 4. Leftward and rightward travel of the assembly is effected by the alternate introduction of fluid under pressure from ducts 59 and 60.
In the position of the valve spool shown in Fig. 4 hydraulic fluid from the pump 42 flows via pump discharge 43 into the master valve and between the spaced ends of the plugs 50. From there the uid ows outward through line 34 connected into the master valve housing, the spools 58 confining the flow within the housing to have this described direction during applicaton or communication of lluid pressure to the jacking pistons for lifting the pump rod. At this time, hydraulic liquid from the reservoir enters the master valve through line 46 connected into the housing 48 and discharges at 61, as indicated by the broken lines in Fig. 4, for circulation to the pump intake 45. Therefore, the pressure exerted on the pump intake during the upstroke of the pistons is the .pressure existent in the balance cylinders, and may be conveniently referred to as the balance pressure. .As a result, the pump adds to the balance pressure its characteristic pressure dilerential for communication to the jacking pistons for lifting purposes. During this time, the exhaust outlet 62 from 'the master valve is plugged olf from communication with either line 34 or 46.
On the other hand, when the valve spool assembly is at its extreme rightward position as indicated by the broken lines in Fig. 4, hydraulic Huid from the jacking cylinders backows through line 34 into the master valve unit and discharges at 62 to the pump intake at 45, while the pump discharge 43 is then placed'in communication with line 46 and iluid from the pump then flows to the reservoir 38. Under these conditions, the discharge 61 is plugged olf from communication with lines 34 and 46.
Further in connection with the construction of the plugs 50, their outside diameters are annularly reduced opposite lines 34 and 46, in the discharges 61 and 62, and the thus formed thin walls of the cylindrical plugs are perforated as shown in Fig. 4, to pass hydraulic fluid back and forth.
Another pair of lines 63 and 64 are connected into the master valve housing 48 opposite lines 34 and 46 to receive hydraulic pressure from the jacking cylinders and yfrom the reservoir respectively. These lines are shown in Fig. 5 as extending to a pressure comparing mechanism generally indicated at 65, which is enlarged in Fig. 6 and shown in detail. The mechanism includes tubular housing 66 receiving end plugs 67 between which a piston 68 is slidable in the housing bore 69. An oppositely endwise extending pair of rods 70 and 71 conatteignit nected with the pistonliiyare guided Withr'endwise revciprocationby plugs 67rightwardtravel of the rods beinggopposed by exertion of hydraulic, iluid4 pressure entering the mechanism from line 63, and leftvvard travel being opposed by hydraulicV pressure from the reservoir conducted viaV line 64 to the `-leftward tace, of the piston `68. Since the balance pressure communicated to the balance pistons is in general less than the hydraulic duid indicated at 72.V However, when the Apressure jdiierential j rises beyond a predetermined arnonnt, as for example where the load rexerted by the pump rod-.carried equipment increases above .a certain amount, piston 68 travels to the left and the stepped rod 70 actuates the regulating val-veY lever v'73 to the brokenflne position shown in Fig. 5. Under these conditions, compressed gas supplied from,V the tank via line 74 to the regulating valve 72, and t-hen normally via line 75 to a clutch indicated at 76, is bled od at 7.7 allowing .the clutch to engage. Consequently, the motor 78 which is always running then drives the compressor 79 through ia V-belt 80 engaged by the clutch, and additional gas is compressed into the tank. Clutch *76 may normally `have a spring acting `to urge a movable'sheave toward the V-belt 80 for engaging same, and a-rnovable piston urging the -sheave away from the V-belt under the iniluence 'of compressed gas frontline 75.
O11 the other hand, should the hydraulic fluid pressure `from the jaclsing cylinders and communicated .to the mechanism `65 via line 63 drop below a predetermined level, vthe pressure trom the tank exerted against lthe left `face of piston 68 plus the action of the spring in the regulating valve 72 will displace the piston 68 and rod 731 to the right, and the latter will actuate .a hleeder valve 81, for bleeding excess gas pressure in thetank or reservoir from the valve 81 via line 82. Therefore, the desired pressure differential will tend to be maintained as respects therelatiouship between the balance pressure and the hydraulic duid pressure associated with the balance and jacking pistons respectively.
Turning back to Fig. 4, leftward and rightward travel ofV #the valve spool S is under the control ofa'pilot valve indicated generally at 83, and including elongated housing 84 containing la bore 85 in which another valve spool assembly 86 is axially `endwise reciprocable. *The latter includes a pair of pistons 87 at opposite ends of lthe .spool shait 88 and a pair of intermedi-ate and spaced pistons 89 which are axially endwise movable between Vlbores 90 in which they are shown 'as received, and 'bores 91. In the position shown, hydraulic iluid pressure from 'the pump discharge at 43 enters 'the housing 84 via `line 92 and ows between the spools 89 and outward via line 59 to the master valve for urging its spool assembly 55 leftwardly to the position in `which it `is shown. vDuring such leftward travel, hydraulic Huid from line 60 flows back to the pilot valve and then ont discharge 93 as shown by the broken lines, through a hand operated valve y94- and to discharge line 95 com- Vrnunicating with the pump discharge. Valve 94 may be opened or closed to the degree as ydesired for restricting backward flow ot duid throughthe pilot valve and there- A'by controlling the rate at which the valve spool 55 travels in the master valve assembly, in turn controlling the stroke of the pump rod 28.
In like manner, when the pilot valve spools 89 are inthei alternate position received within bores 91, uid from the pump Vdischarge at 4?` iiows into the pilot valve through line 92 and out through 'line 60 to the master `valve for urging valve spool 55 rightwardly. At
valve 97 and to the discharge 95. As above, valve 97 may be 'adjusted in relation to valve 94 to control the upward travel .of the pump rod. Y
Shifting of the pilot valve spool 86 in response to' reciprocation of the balance piston 21 shown in Fig. 3 is accomplished by operation of the actuating mechanism generally shown at 98 to include a vertically extendingfrod 99 reciprocable up and down by the pis-ton ,extension 19 towhich the rod is connected by link 100. The upper end of the rod extends through asleeve 101 carried by the transverse link 100, anda set screw 102 threaded in the sleeve and engaging the rod, is adjustable to permit control of the rod position relative to the piston extension 19 lfor changing the stroke length of the pistons and the pump rod 28.
Actuating rod 99 is movable in a vertically extending f protectiveunderground tube `103 extending downward lfrom connecting ring 15 supporting cylinder 104 through which the rod 99 projects `upward and above ground surface level 16. .As better shown in Fig.l 4, housing 104 contains a cylinder 116 and a piston 105 reciprocable up and down in thercylinder bore 106, with cylinder end plugs 107 guiding the upper and lower piston extensions 108 and 109 projecting through the plugs. Boththe .piston and its extensions are tubular so that the rod 99 may reciprocate axially therethrough, suitable O-ring seals 110 and 111 being provided to seal vof between the piston 105 and bore 106, and between the piston extensions and the end plugs 107, all for the purposes of retaining hydraulic fluid within the bore spaces 112 and 113 above and below the piston itself. The fluid in spaces 112 and 1113 communicates respectively with the pilot valve lend spools 87 via lines 114 and 115, so that the pilot valve spool assembly is displaced endwise in accordance with a change in the direction of travel of piston 105.
Housing 104 contains hydraulic iluid standing at a level above check valve intakes 117 to extensions 118 and 119 of lines V114 and 115 respectively within the housing 104, it being understood that liquid may be drawn into those extensions and into the bore spaces 112 and 113 when suction pressures exist therein. Aiso, suitable ball check pressure Yrelief valves 120 `are connected into the ttings 121 and 122 joined to the cylinder 116 and through which fluid in "lines v1114 and -communicates with the bore spaces 112 and 113 respectively. Thus,
should fthe'lpressure developed by displacement of piston -105`lexceed fa predetermined level, hydraulic huid will `escape into the `duid-chamber 123 'in housing 104.
`Refer-ring Vto the operation `of the actuating mechanism indicated vat 98 in Fig '13, it will be seen that upward displacement of the actuating rod 99 bythe balance piston extension 19 will bring a shoulder 124 at the lower end of rod 991`into engagement with lower end of piston extension 109, vand further upward travel of Vrod 99 will displace Vpiston 105 vupwardly `in bore 106, eiecting a shifting of the Apilot `valve spool assembly v.'56 from the position shown in Fig. 4 to its alternate position. Conversely, downward travel of 'the'balance piston extension irl-9 will -cause link 100 to engage the upper end of the piston extension 108;, thereby displacing piston 105 .downwardlyin'bore 106 and eitecting shifting of the pilot valve spool :assemblyo to the position shown in Fig. 4. Operation Arcomplete .cycle of operation yof the pump jacking apparatus'will now be described. At the completion of the pump rod downstroke and at the beginning of its upstroke,1the lpilot Valve and master valve spools S6 and u55 are inthe position -shownin lFig. 4, `facilitating `direct communication of hydraulic fluid pressure from the ,pump discharge 43 -to the jacking pistons ,'22, via lines 33..and .3.4, vthe spaces lbetween the jacking cylinders '13 andthe pistons 21, Vand @the i clearances between the cylin- .ders of .the .fjaclringcpistonheads 32. At this time, fluid :stands lat level 39in the reservoir tank 38 asshown in ',Fig. l, and during the jacking piston and pump rod upfstroke, fluid Viiows from the reservoir to the pump intake 45 via the master valve, as explained above. The Vpump is driven by theV motor 78, as by the V-belt drive shown in Figs. l and 5, preferably at constant speed, so that the pump rod 28 is steadily lifted, and the liquid level in the reservoir tank 38 falls to the broken line level indicated at 40. n 4
Near the completion'of the pump rod upstroke, the actuating rod 99 effects the lifting of the piston 105, with consequent shifting of the pilot valve and master valve spool assemblies 86 and 55. This time, hydraulic fluid in the jacking cylinders is placed in communication with the pump intake 45 via the master valve, as explained above, and the pumpv discharge 43 is connected with the iluid in the reservoir 38, also via the master valve and lines 46 and 36 as shown in Fig. 2. Therefore, the only hydraulic liquid pressure tending to lift the pump rod 28 is the balance pressure exerted on the balance piston head 31, so that the pump and rod begins its downstroke, together with the jacking and balance pistons. During such downstroke, the pump 42 driven at constant speed brakes the downward travel of the jacking pistons since hydraulic iuid under pressure exerted by those pistons can iiow through the pump only as regulated by the pump speed. Therefore, the pump meters or restricts hydraulic iiuid ow toward the reservoir 38, and the level of fluid in the reservoir rises at aV constant rate in accordance with such metering to the upper level 39 at the completion of the downstroke.
Oil standing in the lower section of the reservoir is conveniently cooled by air blown between the outer and inner shells 130 and 131 by means of a fan 132 rotated by pump shaft extension 133 in the inlet 134, as indicated in Fig. 7. After passing in cooling relation to the oil standing within the inner shell 131 of the reservoir, air flows through the outlet 135.
Reference to Fig. l shows the pump 42, reservoir tank, compressor, and valves 43 and 44 mounted on a frame 137 standing on the ground, whereas the actual jacking cylinders and pistons extend well below ground level, It is of course understood that the reservoir tank 38 may be mounted horizontally to decrease the height of the equipment standing above ground.
I claim:
l. An apparatus for vertically reciprocating a loaded rod at a constant uniform rate onthe downstroke thereof irrespective of variation of the magnitude of said load on said rod which includes: a plurality of substantially vertically extending and laterally spaced cylinders adjacently disposed to said rod; piston means reciprocal up and down in said cylinders; a reservoir partially filled with hydraulic fluid and having a quantity of gas at at least a predetermined minimum second pressure situated thereabove; a source of gas at a pressure substantially higher than said second pressure; a positive displacement pump; a prime mover which when operating continuously drives said pump; first valve means which include a movable valve member capable of occupying first and second positions; first conduit means which when said valve member is in said first position have said iiuid fiowing therethrough from said reservoir to the suction of said pump to be discharged to a first portion of said cylinders at a first pressure higher than said second pressure to cause said pistons therein to rise and raise said loaded rod; second conduit means which when said valve member is in said second position and said loaded rod moves downwardly from the top of its stroke have said hydraulic iiuid owing therethrough from said first cylinders to the suction of said pump, and the discharge of said pump being conducted by said second means to said reservoir, with the rate at which said uid is pumped through said pump solely determining the rate at which said loaded rod moves downwardly on the downstroke thereof; means responsive to the movement of said loaded rod that move said valve member to said first position at substantially the termination of the downstroke lofsaid rod and to said second position at substantially the completion of the upstroke by said rod; Ythird conduit means extending between said reservoir andv said second portions of said cylinders to force said pistons therein by fluid at said second pressure to support a predetermined fraction of said load on said rod on both the upstroke and downstroke thereof; and means sensitive to the pressure of said gas in said reservoir and said uid at said first pressure that bleeds gas from said reservoir, or admits gas from said source to said res- -ervoir to automatically maintain a predetermined differentialin pressure that is substantially constant between said rst and second pressures to 4force said pistons in said secondV portions of cylinders to support said predetermined fraction of said load on said rod on both the upstroke and downstroke thereof, even if the magnitude of said load over a period of time varies.
A2. An apparatus as defined in claim l in which said source of gas under pressure is a gas compressor, and
-an air pressure controlled clutch is provided capable of driving said compressor together with transmission means connecting said clutch to said prime mover, and the air pressure on said clutch varied to place said clutch `in a compressor driving position to supply gas to said reservoir until the pressure of said gas in said reservoir has risen sufiiciently to establish said predetermined differential between said first and second pressures by opand said first passage, a second conduit connected to the l interior of said reservoir and said second passage, a third conduit connected to the suction of said pump and said third passage, a fourth conduit connected to said fourth passage and the interior of said `first portions of said cyl- Yinders, with said member disposed in said body, and
when said member is occupying said first position establishing communication between said first and fourth passagesand said second and third passages, and said fifth Vand sixth passages connected to said second conduit means.
V4. An apparatus as defined in claim 3 in which said l second conduit means includes a fifth conduit connected to said fifth passage and said suction of said pump, a sixth condult connected to said sixth passage and the interior of said reservoir, and said member in said valve when in said second position establishing communication between said fourth and fifth passages yand said first and sixth passages.
5. An apparatus as defined in claim 3 in which movement of said valve member in said valve body is in response to hydraulic fluid pressure exerted thereon, and a pilot valve is provided that controls hydraulic fluid under pressure that is caused to be exerted on said valve ,member in response to reciprocation of said loaded rod.
6. An apparatus as defined in claim 3 in which said means responsive to the second pressure of said gas in said reservoir and the first pressure of said uid in said first portion of said cylinders is a hollow cylindrical body in which a piston is slidably mounted which has two piston rods extending outwardly from opposite sides thereof-through ksaid body, the end interior portions of said body in communication with said gas in said reservoir and said fluid in said first portion of said cylinders, with a normally closed bleed-off Valve being provided that is in communication with said gas in said reservoir, and `said piston when said pressure of said gas in saidreservoir attains more than a predetermined differential relative to said fluid at said first pressure moving in a direction to cause one of said piston rods to actuate said bleed-off valve to assume an open position until sufficient of said gas in said reservoir has escaped through said bleed-off valve to permit said piston in said body to move out of said position in which said bleed-off valve is actuated.
7. An apparatus as defined in claim 6 in which a valve is provided that controls the air supply tov said clutch, and said piston in said body when said gas pressure in said reservoir falls below said differential relative to said pressure onV said fluid in said first portion of cylinders, moving in a direction to cause one of said rods project- `ing from said piston to actuate said air control valve until said air pressure in said reservoir has built up to said predetermined differential relative to said pressure of said uid in said first portion of cylinders.
8. In a hydraulically operated unit to reciprocate a substantially vertically disposed loaded rod of the type of unit which includes a first cylinder with a first piston movably disposed therein that raises said rod when a hydraulic fluid under pressure is discharged into said first cylinder, a second cylinder and second piston movably disposed therein, which second piston partially supports said load on said rod on each upstroke and downstroke thereof when'hydraulic uid under pressure is maintained in said second cylinder, said first and second pistons being rigidly connected to said rod, the improvement in which the downward movement of said rod is maintained at a desired uniform rate irrespective of variation in the load on said rod comprising: a positive displacement pump capable of discharging hydraulic iiuid under pressure when actuated; a prime mover that actuates said pump at a constant pumping rate; a reservoir of suflcient volume to hold a quantity of said hydraulic iiuid greater than that required to be discharged into said first cylinder to raise said piston and rod on said upstroke a predetermined distance and to cause said second piston at all times to partially support said load on said rod; first Valve means that includes a body having first, second, third, fourth, fifth and sixth fluid passages formed therein, and a valve member movably mounted in said body, said valve member capable of occupying a first position in which said first and fourth passages are in communication as are said second and third passages, and a second position in which said fourth and fth passages are in communication as are said first and sixth passagesya first conduit connected to the discharge of said pump and said rst passage; a second conduit connected to the interior of said reservoir and said second passage; a third conduit connected to said third passage and the suction of said pump; a fourth conduit connected to said fourth passage and the interior of said first cylinder; a fifth conduit connected to said fifth passage and said suction of said pump; a sixth conduit connected to said sixth passage and the interior of said reservoir;
a seventh conduit connected to the interior of said reservoir and said second piston; means that at all times maintain at least a predetermined minimum pressure on said fluid in said reservoir to exert an upward force on said second piston at all times to partially support said load on said rod; means responsive to the movement of said rod that moves said valve member to said first position as said first piston approaches the completion of its downstroke and to said second position upon said rod being raised on the upstroke thereof to a predetermined elevation, said Valve member in said first position permitting said pump to draw said fluid from said reservoir through saidsecond and third conduits from said reservoir under a head of at least said minimum pressure and discharge said hydraulic iiuid through said first and fourth conduits to said first cylinder to raise said rod to said predetermined elevation, with said valve member in said second position permitting the portion of said load on said rod not supported by said second piston to move said rod downwardly with concurrent discharge of said fluid from said first cylinder through said fourth and fifth conduits to the suction of said pump to be discharged therefrom through said first and sixth conduits to the interior of said reservoir, and said pump when discharging said fluid through said first and sixth conduits acting as la regulator to control the rate at which said rod moves on said downv stroke thereof.
9. In a hydraulically operated unit as defined in claim 8 in which said means to maintain said substantially constant head on said fluid in said reservoir is a quantity of a gas disposed therein that is at all times maintained above the predetermined pressure required for said second piston to support said desired portion of said load on said rod on both the upstroke and downstroke thereof.
10. in a hydraulic pumping unit as defined in claim 9 in which a desired differential is automatically maintained between the pressure on said fluid in said firstV cylinder and said pressure on said gas in said reservoir by providing a source of said gas at a pressure substantially greater than said minimum pressure, a normally closed gas bleed olf valve on said reservoir, means which when actuated result in the flow of said gas from said source to said reservoir, and a pressure-comparing mechanism including a movable member, said mechanism at all times in communication with said gas in said reservoir and said fluid in said first cylinder, said member responsive to a predetermined differential in pressure between the pressure on said uid in said rst cylinder and the pressure on said gas in said reservoir, said member being moved to a first position when the pressure on said uid in said first cylinder exceeds said predetermined differential relative to said gas in said reservoir, said member in said first position actuating said means to permit iiow of said gas to said reservoir, said member being moved to a second position when the pressure on said gas in said reservoir exceeds said predetermined differential relative to said pressure of said Huid in said rst cylinder, said member when in said second position maintaining said bleed-off valve in an open position to permit discharge of said gas to the ambient atmosphere until the difference in pressures between said gas in said reservoir and said Huid in said first cylinder is at said predetermined differential.
References Cited in the le of this patent
US67880757 1957-08-19 1957-08-19 Pneumatic hydraulic pumping apparatus Expired - Lifetime US2947144A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
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US3058307A (en) * 1960-08-29 1962-10-16 Pneu Hy Co Hydraulic pneumatic well pumping apparatus
US3058308A (en) * 1960-10-17 1962-10-16 Pneu Hy Company Hydraulic pumping apparatus

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US1619474A (en) * 1925-05-04 1927-03-01 Hubbard Machine Company Pumping system
US1925109A (en) * 1933-09-05 Hydraulic chuck
US1943061A (en) * 1929-10-21 1934-01-09 Oilgear Co Hydraulic drive for machine tools
US2167623A (en) * 1936-08-15 1939-08-01 George H Britter Fluid operated pump jack
US2276016A (en) * 1940-03-22 1942-03-10 Westinghouse Electric & Mfg Co Hydraulic well-drilling apparatus
US2541887A (en) * 1943-09-16 1951-02-13 Payne William Harvey Means for automatically adjusting arc furnace electrodes
US2564285A (en) * 1948-03-11 1951-08-14 Samuel V Smith Pneumatic-hydraulic system for operating well pumping equipment
US2617256A (en) * 1948-06-12 1952-11-11 Pelton Water Wheel Co Hydraulic pumping jack control
US2763128A (en) * 1952-12-08 1956-09-18 Joyce Cridland Co Low level oil control for hydraulic lifting mechanism
US2803193A (en) * 1954-04-09 1957-08-20 Herbert M Salentine Long stroke well pump reciprocator

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Publication number Priority date Publication date Assignee Title
US1925109A (en) * 1933-09-05 Hydraulic chuck
US1619474A (en) * 1925-05-04 1927-03-01 Hubbard Machine Company Pumping system
US1596145A (en) * 1925-11-14 1926-08-17 Lee J Black Hydraulic pumping system
US1943061A (en) * 1929-10-21 1934-01-09 Oilgear Co Hydraulic drive for machine tools
US2167623A (en) * 1936-08-15 1939-08-01 George H Britter Fluid operated pump jack
US2276016A (en) * 1940-03-22 1942-03-10 Westinghouse Electric & Mfg Co Hydraulic well-drilling apparatus
US2541887A (en) * 1943-09-16 1951-02-13 Payne William Harvey Means for automatically adjusting arc furnace electrodes
US2564285A (en) * 1948-03-11 1951-08-14 Samuel V Smith Pneumatic-hydraulic system for operating well pumping equipment
US2617256A (en) * 1948-06-12 1952-11-11 Pelton Water Wheel Co Hydraulic pumping jack control
US2763128A (en) * 1952-12-08 1956-09-18 Joyce Cridland Co Low level oil control for hydraulic lifting mechanism
US2803193A (en) * 1954-04-09 1957-08-20 Herbert M Salentine Long stroke well pump reciprocator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3058307A (en) * 1960-08-29 1962-10-16 Pneu Hy Co Hydraulic pneumatic well pumping apparatus
US3058308A (en) * 1960-10-17 1962-10-16 Pneu Hy Company Hydraulic pumping apparatus

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