US2697985A

US2697985A - Well pump and operating mechanism therefor

Info

Publication number: US2697985A
Application number: US260454A
Authority: US
Inventors: Charles C Carlisle
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-12-07
Filing date: 1951-12-07
Publication date: 1954-12-28
Anticipated expiration: 1971-12-28

Description

DCC- 28, 1954 c. c. CARLISLE 2,697,985

WELL PUMP AND OPERATINGMECHANISM THEREF'R ATTQRNEYS.

Dec. 28, 1954 c. c. CARLISLE 2,697,985

WELL PUMP AND OPERATING MECHANISM THEREFOR Filed Dec. 7, 1951 5 Sheets-Sheet 2 Dec. 28, 1954 c. c. CARLISLE WELL PUMP AND OPERATING MECHANISM THEREFOR il? Fili 1||| ATTORNEYS.

Dec. 28, 1954 c; c. CARLISLE WELL PUMP AND OPERATING MECHANISM THEREFOR Filed Deo. 7, 1951 5 Sheets-Sheet 4 C. C. CARLISLE WELL PUMP AND OPERATING MECHANISM THEREFOR Filed Dec. 7, 1951 Dec. 28, 1954 5 Sheets-Sheet 5 INVENTOR. Char/es C Car/l's/e.

BY Mdm ATTORNEYS.

WELL PUMP OPERATING MECHANISM THEREFOR This inventionirelates, to pumpsffor removing fluids from wells particularly where the., uidsare to .be lifted from 4substantial depths, the ypresentinvention.being an improvement over the pumping apparatuses disclosedm Patent No. 2,118,547 issued to me May 4, 1938, for Deep Well Motor and Patent No. 2,287,779 issued to me "June' 13, 1942, for .DeepfWell Pumping Mechanism?, Pumps of the character .disclosed in the patents are very desirable for lifting uids from great depths for the reason that the` actuator or power unit which operates the pump piston is located within the well and connected with the 2,697,985 Hatented Dec. 28, 1954 ICC an inlet tubev that depends from standing valve cage '11* of the pump.

' .The .standing valve cage 11 includes a lower section 12 having an annularly tapered lower end 13 to removably seat within an internal annular taper 14 of the collar 7 and form a seal between the well gas anchor 3 and the tubing 4. The standing valve cage has an internally threaded axial bore 15 into which the upper end of the inlet tube 10 is threaded to connect with an upper reduced extension 16 of `the bore. The extension 16 of the bore is formed within a reduced neck 17 of the section 12 toprovide an annular shoulder 18 having a circular series V`ofspring seats` 19 forsprings 20 ,of a valve ringl 21.

, The upperfsection .22 ofthe standing valve cage has an axial bore 23 that is internally threaded as at 24l to lconnectpwith external threadsonthe neck 17 of the lower section. Inset withinthe bore 23` isY a ring 25 for retaining a valve seat 26 against an internal annular shoulder 27. 'The seat 26 mountsla ball valve 28 contained within a valve chamber29 Vthat is provided within the upper Y portion of the bore between the shoulder 27 and a transpump unit bya short mechanical linkage. Therefore, rod

. problems of deepwell pumps are eliminated. The pumps also have the advantage in that they effect lift of the well uid on both the up and down stroke of the pump piston. However, the pumps ofthe patents cannot produce a constantly uniform volumetric ow of the well,

uid to the top of the well because of differential effective areas at therespective ends of the power piston and different volumetric capacities of the upper and lower'pump chambers. t i

lItistherefore the principal objecttof the present in Avention-to provide` a pump structure which overcomes .these inherent inefficiencies lof pumps disclosed in the fpatents by providing substantially the same effective areas at the respective ends of the powerpiston and substantial- @ly the same volumetric displacement of the well uid from;l f.,

the respective pump chambers. i Other objects ofthe invention -are to provide for smoother acting power and pump units; toprovide a more positive operation of the automatic control mechanism and thereby eliminatepossibility of the pump `stopping on dead `center position;,and to provide apower` and pump unit having greater over-all efficiency relatively to the volume of power uid required to operate the t power unit. Y

In accomplishing these andother objectsof the invention, I have provided improved structure, the preferred -form of which is illustrated inthe accompanying drawings wherein:

Figs. l, 1A and.1B illustrate-the upper, mid and lower I :portions of a well pumping `apparatus includingpower ,fand pumpunits constructed in accordance with thepresent 'invention and shown installed within a1well. t

w vnFigs. i2, 2A, 2B, 2C and 2D are enlargedvvertlcal sections through the pumping apparatus.

Fig. 3 is a perspective-view of the toggle mechanism of the'automatic control apparatus.

Fig. 4 is la cross section on the line 4--4 of 3; y Fig. 5 is a cross section on the line 5-5 of Fig. 2A. Fig. 6'is a cross section on the.line'6-,6 of Fig..2B.

I Fig. 7 isa cross section'onthe line 7-7 of Fig. 2C. p

Fig. 8 is a cross section on the line 8-8fof Fig-2D. V,

1 Fig. 9l is a cross section-,on the-line 9;-9 of Fig. 2D.

yReferring more indetailto the drawings:

VV1 designates a pumping vapparatus constructed in acchgr 8that is: supported on the ybottom-of the well and providezl-.with` suitable apertures 9 through jwhich the `well fluid' ows into the gas anchor for jupflow throughy A -cordance with the present invention and includes a pump t unit,2,.and ,a closelyeoupled:actuator or power unit 3` adapted Y,to be located within the lower portion of a well, "indicatediby Vthecasing or tubing- 4 that extends from near .thefbottom of the well'to above ground and vcof -operates with ani innerflow tubingS in forming an annular Verse guard 30 having suitable openings 31 for passing vwell fluid into and out of the lower end of the pump unit.

, that is connected with thej upper cage section 22.

The pump cylinder has a lower head 36 threadedly connected therewith as indicated at 37. The head has atreduced exteriorly tapered portion 38 which removably engages within a tapered seat 39 of a seat member40 y having a reduced neck portion 41 threadedly connected with the upper end of the upper valve cage section 22. The

parts

36 and 40 have registering

bores

42 and 42 that connect the openings 31 with channels 43 leading to the lower end of the pump chamber 44 and through which the well fluid is drawn into and discharged from the lower end of the pump cylinder as later described.

Formed in the section 22 of the standing valve cage, in encircling relation with the bore thereof, is a series of ports 45 extending through the lower end thereof to pass fluid discharged fromv the lower chamber of the pump cylinder and. which connect with the upflow passageway 6, the outlets being controlled by the Valve ring 21.

Located intermediate the ports 45 are ports 46 that connect with the axial bore 25 below the valve 28. The upper ends ofthe ports 45 extend through the upper end of the cage section 22 and connect with an annular passageway 47 that is formed between the pump cylinder 32 andthe tubing 33. The upper end of the passageway 47 connects through ports 48 with a valve chamber 49 in the upper pump head 50, the, ports being controlled byra valve ring 51 contained within the annular valve chamber 49 and normally seated rby springs 52. The upper head 50 has an axial bore 53 to pass the well fluid from the valve chamber into the upper pump chamber 54. Slidable within the pump cylinder and separating the upper pump chamber from the lower pump chamber is a piston which is reciprocated by the power unit as later described. The well fluid is discharged from the upper pump chamber Vthrough ports 56 that connect the valve 'chamber 49 with an upper valve chamber 57 that is formed a piston,rodtcoupling64 ,to connect a piston rod 65 (Fig.

213)." The piston rod is reciprocable through registering

bores

67 and 68 in the upper head of the pump andjthe lower head of 'the power unit;

- .The `cylinder head 5 0 is preferably composed of a cylindricalbody section 69" provided with reduced externally -ciprocably mounted within a power cylinder 92. .powereylinder 92 is contained within the tubing 5 and the wall of the power cylinder is spaced inwardly thereof d threaded ends 70 and 71 to connect with the upper end of the tubing 33 which surrounds the pump cylinder and a lower skirt portion 72 of a part of the head in which the outlet ports 56 are formed. The end portion 71 has a reduced depending extension 73 that is externally 'threaded for connecting the upper end ofthe pump cylinder as indicated at 74. The lower head `of 'the power cylinder has a reduced externally threaded neck 76 to which a section of tubing 77 of the tubing 5 connects. Formed within the neck portion of the upper section is a ksocket 78 for receiving a packing element 79 and which is retained in 'sealing Contact with the piston rod by a packing gland 80 that is contained -in a counterbore 81 by a nut 82.

It is obvious that when the piston 55 is moved upwardly within the pump cylinder 32, -Well lluid is drawn into the inlet tube 10, bores 16 and 25, past the ball valve 28 and through the openings 31, bores 42 and 42 and channels 43 into vthe lower end of the pump cylinder to ''ill the lower pump chamber 44. Simultaneously, upward movement of the piston discharges well fluid from the upper pump chamber 54 'through the passageway 53 surrounding the piston rod 65, valve chamber 49 and ports 56 to unseat the valve ring 59 and pass into the upper valve chamber 57 for discharge through the ports V61 into the upflow passageway 6. On the downward movement of the pump piston 55, the ball valve 28 seats and the valve ring 21 unseats so that the fluid trapped below the piston '55 is discharged into the up'liow passageway 6. Well fluid is thus lifted on both the up and down stroke of the pump piston.

From the structure thus far described, it is obvious that 'the space in the upper pump chamber 54 is restricted by the piston rod 65, and since the piston rod 65 must be of relatively large cross section to withstand the compression and tension stress thereon, the fluid capacity of the upper pump chamber is substantially less than the fluid capacity ofthe lower pump chamber. Therefore, more fluid would be displaced bythe pumps ofthe patent on the downstroke than on lthe upstroke. As above stated, it is a principal object of the present invention to overcome this ditiilcul'ty by providing equal capacities for the upper -and lower pump chambers. This is eiected by providing a standing piston or vrod 83 having alength substantially corresponding with half the length of the pump cylinder and providing a displacement within the lower ,pump chamber substantially cor-responding with 'the displacement causedby the pump rod 65 and which forms a guide rod over which the piston is adapted -to operate.

The .rod 83 is mounted coaxially of 'the .pumpcylinder and as stated has across sectional area conforming with the cross sectional areaof the piston rod. The stationary rod is mounted lon the lower cylinder head 36 andhas a .reduced threaded end 84 turned within a threaded opening 85 of the lower cylinder head as clearly shown in Figs. 1B and2D. The stationary rod extends upwardly coaxially of the .pump cylinder and is of suliicientr length so that when the piston is at the top of 4its stroke, the free end portion 86 of the stationary rod-is contained within lan axial bore 87 of the pump piston-as best shown in Fig. 2D.

A .Huid-tight seal is maintained about the stationary rod by a nut or collar 88 that is threaded on a depending neck 89 of the piston and contains a packing 90. With this arrangement it is obvious that bothpump chambers comprise annular spaces between the pump cylinder and the respective pump and stationary rods of equal capacities so -that the amount of well iiuid drawn into the respective pump chambers is substantially equal and equally displaced therefrom incidental to operation of the piston 55. Consequently, Vthe volumetric Ilowof the well uid throughthe upow duct isy continuous and uniform as long as the power piston of the power unit operates with -the same relative speeds on the 'up and down strokes of vthe respective pistons.

The power unit includes a power piston 91 that is rei The to .provide an annular flow passageway 93. The lower end of the power cylinder is closed by 'aplug 94 that is threaded therein and provided with an axial bore 95 to pass the piston rod 65. Theplug '94 has anannular skirt portion 96 encircling the packing'nut 82 and which seats on the -upper end of the part58.

The power cylinder extends upwardly within `the tubing `5 and connects with an externally threaded skirt 97 of an upper head 98 and to which the tubing section 92 also connects. The upper end of the head 98 in turn connects gvgth the lower end of the wel1 tubing 5 as indicated at The pump piston includes an elongated central body portion 100 closely fitting within the pump cylinder and having an axial bore 101 for accommodating a trip rod 102. The lower end of the piston body has a reduced externally threaded neck 103 on which is mounted a coupling 104 having a transverse web 105 closing the lower end of the bore 101 and which forms an abutment for the pressure iiuid admitted to the upper end of the pump cylinder to etect downward movement of the pump piston. The coupling 1'04 has a threaded socket 106 mounting the upper threaded end 107 of the pump rod 65 as best shown in Fig. 2B. The coupling is formed to provide a space 108 between the transverse partition 105 and the end of the rod 65. This space 108 is connected with a lower chamber 109 of the power cylinder through ports l110 for a purpose later described.

The upper end -of the 'central body `of the power piston is provided with a reduced externally threaded neck 111 mounting a piston head 112. The piston head 112 is formed with a transverse partition 113 and which is provided with an axial opening 114 to pass the trip rod 102 -therethrough as shown `in Fig. 2B. The trip rod 102 has spaced

collars

115 and 116 fixed thereon and which are adapted to be alternately engaged by the respective sides of `the partition 113 when the piston is reciprocated responsive to control flow yof pressure uid under action of a valve mechanism 117 which substantially conforms to vthe valve structure disclosed in the above number Patent 2,287,779 for controlling ow and discharge of pressure iluid from upper and lower chambers of the power cylinder.

The valve mechanism comprises a main valve assembly 1148 and which is described 'in detail in Patent No. 2,287,779. The main valve assembly is contained within a valve housing 119 which comprises a cylindrical tube having its upper end 120 threadedly engaged with threads -on the inner vside of the skirt portion 97 of the head 98 'so that the housing depends within 'the tubing 92 to provide an annular passageway 121 extending the length of the housing and directly connected with the upper power chamber 122. The interior of the valve housing and head 98 provide a cylindrical valve chamber 123 which cooperates with an upper valve chamber 1.24 formed in the upper --head 98.

yThe valveV housing also lhas a -lower cylindrical valve chamber Y125. The Yvalve chamber 125 is of smaller diameter than the valve chamber 123 and rprovides an annular "shoulder `126 forseatingl the valve assembly in one position thereof. The valve assembly `includes a main piston-like portion 127 which is slidably lcontained within the -va'lvechaniber 123 and fconneoted'with a pistonlike valve 'portion 128 contained inthe valve chamber V124, the piston portions lbeing connected by a reduced sleeve portion 129. The main valve assembly also includes a lower piston-like portion 1300i smaller diam- -eter and containedwithin 4the lower valve chamber 119 as 'shown' in Fig. 2A. Extending -upwardly from 4the main pistonf portion 128 is a sleeve 'portion l3'1having spaced ears 132 and .f1-33 .(Fig. 3) to which .toggle -

levers

134 and 135 are connected.

The lmainvalve 'has a longitudinal bore 137 that has a reduced portion 138 extending downwardly within the piston portion '130. The lower piston portion 130 has a reducedextension 139 that operates with thelower bore of the`valve housing to form an 'annular vertical .passage 140 'that connects with the pilotl 'valve 'chamber through ports 141. The ports 141are-'adapted to .'be connected with ports 142 leading to channels 143 that extend upwardly through the main valve body to connect with the valve chamber `-123. The pasageway121 connects at itsupper end with the valve chamber 123 through ports 144 that are under control 'of 'the piston portion 127 of the mainvalveV while the lower end of the passageway 121 connects with the upper yend of the power chamber 12.2. The annular ilow passageway 93 extends upwardly ing under-control 'of lthe upper piston'portion 128. The

lower end of thepassageway 93 connects with thelower Lend vofthepower chamber 109throu'gh =ports 147 which are arranged Iin vertically spaced zannular'series `'with the in its cylinder.j 4 Y j When the power piston is moved suiiiciently in either direction for the part 113 to engage .the respective collars 'upper series beingof larger diameter than the lower series for they purpose lateide'sczribe'd'.v The main" 'valve also has ports 146 located drectly below the piston port1i 23111 127 which supply pressure uid to the passageway The upper valve chamber also has ports 148 that connect through channels"I 149 with ports 150 in an annu lar valve seat 151. The ports 148are under control of the piston portion 128 of the main valve while the ports 150-are controlled-by a ring-shape valve- 152z that=is yieldingly retained on' the seat by, springs 153 that rare contained in an annular chamber 154v which is connected with the upow passageway or duct 6 through ports 155. The upper' end of the pilot valve chamber` issupplied with pressure uid through the annular space around the rod member '163, Fig. l, `arid'inside of the sleeve portion 131 where there is ample space, yet a small portion of the ,pressureiluidzows through theports 156.

`Then `pilot valve includes piston-like y-valvirig Vportions 4157 and 158jconnected by a' reduced sleeve portionf159.

than the rod 102 to provide a passageway 161. The; upper end of the pilot valve isl connectedby a cage 162 with a tubular rod 163 that extendsfupwardly of the trip rod and terminates in a threaded pin 164 for connecting the box end 165 of a tubular member. 166 which forrnsan 'upward'continuation ofthe tubular rod l'163) The trip rod, previously mentioned, extendsupwardly through a stui-ling box 167 that is carried bya plug' 168 closing the lower end of the valve housing as shown in Fig. 2A. The trip rod 102 also extends through va packing 169 contained in a stuing box 170.011` the lower end of `the main valve assembly. The packing is retained `by a bushing 171 protected within a cap 172 which forms the terminalend ofthemain valve assembly. The cap 172 has an endface 173 whichcooperates with the upper end face of the plug and the wall of the main valve casingto form a pressure chamber 174 to balance thepres- `sure on the respective ends of the valve assembly. The

pilot valve chamber has a similar pressure space 17'5by which pressure is substantially'equalized on the respective ends of the pilot valve.

The

links

134 and 135 are pivotally connectedwith the

ears

132 and 133 by

pins

176 and 177; The links extend upwardly alongside the members 1 63 and 166 and f are pivotally connected by

pins

178 and 179 with the terminal ends of toggle levers 180 and 181 that are pivotally mounted ontrunnions 184 and 185 that project laterally from opposite sides of the member 166 as b est shown in Fig. 3. The

links

134 and 135 areresiliently `springs 195 which are sleeved over the respective studs.

To this construction the `springs exert pressure between theheads 193` andanges 194' to drawthe

bars

187 and 188 in contact with the

links

134 and 135 to support thelinks with the toggles in either their up or down position. When the toggles are in their up position as shown in Fig. 3, the power piston is moving downwardly and when the toggles are in their lowermost position,` as

shown in Fig. 2, the

power piston'is movingupwardly

115 and 116, the toggles are shifted through their repective positions to effect actuation of the pilot valve as later described.

The toggles are under control of a trip spring 196 which is not to be described. .l yThe upper end of the member 166 has a threaded pin 197 connected with a box 198 ofl a tubular housing 199 that extends upwardly within the tubing 6 and has an internally threaded box 200 receiving a threaded pin 2,01

of atubular guide housing 202. Slidable in the1 gu ide housing 202 is a pilot .tube '1203,1tha`tIisfconriectedbyla coupling 204. witha tube 205' of substantially smaller diameter` than the tube 199to accorrirn'odatefy the trip spring 196 which is coiled about the inner tube 205 andhas its 6 'upper end bearing against a collar 206 which seats against Aa shoulder 207' on the' coupling 202.' The 1owe'r`ei1d of the spring seats against the upper end 208 of a tube 209 Athat is slidablymounted within the tube 199 and h as its and 181. The upper end of the spring 19.6 acts against the collar 206 to support the trip rod in its upper position through its connection with the tube 205. When the trip spring 196 is in expanded position, the' toggles are held in their up or down position as shown in Figs. Z-.an'd 3 so as to retain the pilot valve' in its respective positions to control ow of pressure iluid to Ythe mainvalve assembly. "i

Assuming that the pumping apparatus is assembled and installed within a well so that well iluidows through Vthe openings 9 of the gas anchor and upwardly through the inlet tube'10 tothe respective ends ofthe pump cylinder, a iluid, `which may be a part of the fluid pumped from the well, is pumped into the inner tubing 5 to effect actuation of the power unit.

When the power plston and pump

pistons

91 and 55 are at the lower ends of their

respective cylinders

92 and 32, the part 113 of the power piston is in engagement with the lower stop 116 of the trip rod 102, and the pilot and main control valves are in the position shown in Fig. 2A.

The pressure fluid ows from the inner tubing through the ports 156, bore 137 of the main valve unit, ports 146, channels 145, annular longitudinal passageway 93, ports 147, and into the. power chamber 109 to `act upon the lower end of the power piston. The pressure `iluid also actsthrough the ports of the rod coupling 104, space 108 and axial bore 65 of the connecting rod 65 to exert pressure between the end 86 yof the fixed rod 8 3 andthe 'inner face 64, of the coupling 64 to supplement the pressure acting on theannular area at, the lower endof the power piston whereby the effective pressure areas at the lower end of the power piston are substantiallyjequal to `the effective pressure'area of the upper Vend of the power piston. f

The pressure uid thus raises thepower piston inthe power cylinder, the pump piston and the pump cylinder *through the connecting rod 65.

Upward movement of the pump piston 55 creates a vacuum within the lower pump chamber 44 so that well fluid lifts the standing valve 28 and rises through the

ports

42', 42, and 43 into the lower end of the pump cylinder to till the expanding chamber 44.

Simultaneously, welltluid which has been previously admitted to the upper pump chamber 54 on ai previous downstroke of the pump piston is being discharged through the passageway 53 into the valve chamber 49 fordischarge through` theports 56, valve chamberl60 andpprts 61 into the upowpassageway 6.v When the power pistonA reaches the position wherethe part y113"thereof"engages the upper is'top.; 1 15 on the-trip-rod 102,`the Vtriprod is moved upwardly therewith to cause the collar'212 to liftthe tube 208'which seatsthe lower end of the spring 196. yThis movement begins to compress the spring 196 until the action therein is sufficient to lift the tube 199.

As the'tube 199 is lifted, the trunnions 185 on the connecting tube 166 move upwardly to press the toggles outwardly againstactiou on thesprings195 through-the links 1314- and and bars 187 and 183 ofthe clamp 1 86. lAs

.the trunnions continue'their travel, the toggles, pass dead and" againstfftlie lower fend 173f the mainvalveL'TThe *main valve,'i.'the`refore,' moves upwardly "funder thi`s"'p`res 's'ue so thatthe piston portion 128 `pas"s'es"the'portsf146, andfthe pisto'riportionf 12.7 vpasses theports`144, "Now,

1.? the passageway 121 into the upper end `ofthe power cylinder Ato act against the upper end of the power piston and start downward movement thereof.

Simultaneously, the pressure fluid in the lower end of the power cylinder is discharged through the ports 147 into the passageway 93 to be Vented through the passages 145 which are then in communication with the valve chamber 123, ports 148, channels 149, valve chamber 154 and ports 155 for upflow with the well Huid which moves upwardly through the upow duct 6.

The power piston is now moving downwardly to effect downward movement of the pump piston to displace the well fluid from the lower pump chamber 44 and to draw in well fluid into the upper pump chamber 54 by way of the

ports

16, 46, passageway 47, ports 48, valve chamber 524, and passageway 53 and to the upper pump chamber Simultaneously, the well fluid in the lower pump chamber 44 is being discharged through

ports

43, 42, 42', 45 to the upow passageway 6.

When the portion 113 of the power piston engages the stop 116, the trip rod 102 is shifted downwardly to apply load on the upper end of the spring 196 to push against the tubular rod 209 and carry the toggles downwardly. When the toggles pass dead center the springs snap the pilot valve to a position with the ports 141 in communication with the ports 142 so that the fluid pressure acting in the chamber 174 is allowed to exhaust through the passageway 140, port 141, ports 142, passageways 143, ports 148, passageway 149 to the valve chamber 154 and fromv the valve chamber through the ports 155 to the upilow passageway 6. This allows the main valve to return to the position shown in Fig. 2A. An up stroke is started to continue litt of the iiuid in the upflow passage` 6 as previously described.

With the structure described, it is obvious that the effective areas at the respective ends of the power cylinder are equalized so that the power piston has the same elective up and down strokes. Also, it is obvious that the pump chambers in the respective ends of the pump cyl-v inder have substantially the same volume so that the discharge from the respective chambers is equal, with the result that the upflow of the well iiuid is continuous and of uniform volume flow.

It is also obvious that I have provided improved and simplified operation for the pilot valve since with the present structure only a single trip spring is used.

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

1. A double-acting pump including a working barrel,

having uid passageways at the respective ends thereof, a reeiprocatory piston in the working barrel, an actuating rod connected with the piston and extending through one end of the working barrel, and a compensating rod having fixed support within the other end of the working barrel in substantially close relation to the fluid passageway at that end of the working barrel and having displacement corresponding to displacement of the actuating rod, said piston being slidably movable over the compensating rod to eect admission and discharge of a well fluid to and from the respective ends of the working barrel and to discharge any sand that may settle around said ixed end of the compensating rod through said closely related uid passageway. 2. In combination with a double acting pump having uid intake and discharge means at respective ends of the pump and provided with a reeiprocatory piston, a double action pressure actuated power means, means connecting the power means with the piston of the pump, means for supplying and exhausting pressure uid alternately from the respective ends of the power means, compensating means for equalizing volume of fluid displaced from the respective ends of the pump, and means for admitting uid pressure to said compensating means for establishing substantially equal pressure areas at the respective ends of the power means and for exhausting the fluid pressure from said compensating means with pressure fluid exhausted from the power means.

3. In a double acting pump having upper and lower sections for elevating a uid, a double acting power unit directly connected with the upper section of the pump, means returning a portion of the pumped uid to eiect actuation -of the power unit for operating the pump, means for equalizing displacement of fluid on both actions of the pump, means cooperating with the displacement means in thelower section of the pump for establishing substantially equal pressure areas on both actions of the power unit, valve means for the power unit for supplying a portion of the returned fluid to the displacement means in the lower section of the pump to render the pressure equalizing means elective and to vent the returned iiuid from the said displacement means in the lower section of the pump simultaneously with the actuation of the power unit.

4. A pump including a working barrel, a reeiprocatory piston slidable in the working barrel, an actuator, a rod connecting the actuator with the piston, means for admitting and discharging a uid to be pumped alternately to and from respective ends of the cylinder, and a compensating rod having fixed support within the working barrel on the side of the piston opposite the connecting rod and having a displacement corresponding with the displacement of the connecting rod whereby the capacities at the respective ends of the working barrel are substantially equal, said piston being slidable upon the compensating rod to form a pressure chamber within the piston, means for supplying a pressure medium to the pressure chamber, and a valve mechanism for controlling the supply of pressure medium to the actuator, and to and from the pressure chamber in the piston.

5. A pump including coaxial pump and power cylinders, pistons slidable in said cylinders, a rod extending coaxially through adjacent ends of the cylinders and interconnecting said pistons, compensating means in the pump cylinder on the side of the pump piston opposite said connecting rod for substantially equalizing the displacement of the pump rod in that end of the pump cylinder, means for admitting a fluid to be pumped into the respective ends of the pump cylinder, and valve means for alternately admitting and exhausting a pressure fluid to and from said compensating means simultaneously with control of the pressure uid supply for the power cylinder.

6. A pump including coaxial pump and power cylinders, pistons slidable in said cylinders, a rod extending coaxially through adjacent ends of the cylinders and interconnecting said pistons, a fixed rod in the pump cylinder on the side of the pump piston opposite said connecting rod for substantially equalizing the displacement of the pump rod in that end of the pump cylinder, said pump cylinder being slidable over the iixed rod and cooperating therewith in forming a pressure chamber within the pump piston in direct connection with the end of the power cylinder adjacent to the pump cylinder, means for admitting a iiuid to be pumped into the respective ends of the pump cylinder, and means for alternately admitting and discharging a pressure uid to and from the respective ends of the power cylinder and to and from the pressure chamber of the piston, said pump piston having a bore cooperating with said pump piston to form a pressure chamber having connection with the pressure fluid inlet at the end of the power cylinder passing said rod which interconnects the pistons.

7. A pump including coaxial pump and power cylinders, pistons slidable in said cylinders, a connecting rod between the pistons and extending coaxially through adjacent ends of the cylinders, a compensating rod having substantially the same displacement capacity as the connecting rod, means supporting the compensating rod in the end of the pump cylinder opposite the connecting rod, said piston having a bore for slidably passing the compensating rod, means for admitting and exhausting an actuating uid alternately to the respective ends of the power cylinder, means for alternately admitting and discharging fluid to and from the pump cylinder, and means for admitting the actuating pressure medium from the power cylinder to act on the compensating rod when the pistons are moved in one direction and for venting said pressure medium to the exhaust of the actuating means on movement of the pump piston in the opposite direction for providing substantially equal pressure areas at the respective ends of the power piston.

8. A pump including coaxial pump and power cylinders, pistons slidable in said cylinders, a rod interconyslidably passing the compensating rod and forming a pressure chamber and piston area substantially equal to the cross sectional area of the connecting rod, means for admitting an actuating iluid alternately to the respective ends of the power cylinder, means for alternately admitting and discharging iuid to and from the pump cylinder, and said connectingirod having a bore in connection with the power cylinder and pressure chamber formed by the pump piston and said iixed rod for admitting the actuating pressure medium from the power cylinder to act on the compensating rod for providing substantially equal pressure areas at the respective ends of the power piston.

9. In a pump of the character described a power cylinder, a power piston slidably mounted in the power cylinder and forming pressure chambers at opposite ends of the power cylinder, a pump cylinder connected in tandem with the power cylinder, a connecting rod coupling having passageways in connection with one of the pressure chambers in the power cylinder, a pump piston slidable in the pump cylinder and having an axial bore, a connecting rod coupling closing the bore at the end of the piston nearest the power piston, a connecting rod having ends interconnecting the couplings and having a longitudinal duct for connecting the passageways of the coupling on the powerlpiston with the bore of the pump piston, a compensating rod iixed within the pump cylinder and having an end extending into the bore of the pump piston to form a pressure chamber in cooperation with said one pressure chamber of the power cylinder to effect equalization in pressure areas on the respective ends of the power piston, means for admitting pressure iluid to the respective ends of the power cylinder to reciprocate the power and pump pistons, and means for admitting and discharging iluid to be pumped to and from the ends of the pump cylinder.

l0. In a pump of the character described a power cylinder, a power piston slidably mounted in the power cylinder and forming pressure chambers at opposite ends of the power cylinder, a pump cylinder connected in tandem with the power cylinder, a connecting rod coupling having passageways in connection with one of the pressure chambers in the power cylinder, a pump piston slidable in the pump cylinder and having an axial bore, a connecting rod coupling closing the bore at the end of the piston nearest the power piston, a connecting rod having ends interconnecting the couplings and having a longitudinal duct for connecting the passageways of the coupling on the power piston with the bore of the pump piston, a compensating rod xed within the pump cylinder and having an end extending into the bore of the pump piston to form a pressure chamber in cooperation with said one pressure chamber ot' the power cylinder to effect equalization in pressure areas on the respective ends of the power piston, means for admitting pressure fluid to the respective ends of the power cylinder to reciprocate the power and pump pistons, and means for admitting and discharging fluid to be pumped to and from the ends of the pump cylinder, said compensating rod having substantially the same diameter as the connecting rod whereby the capacities of the pump cylinder at opposite sides of the pump piston are substantially equa ll. In a pump of the character described a double acting liuid pressure actuator, a valve housing in connection with the actuator, a main pressure actuated valve slidable in the valve housing to control alternate inlet and discharge of pressure uid to the actuator, a pilot valve slidable relative to the main valve for controlling the actuating fluid to the main valve, a trip rod having spaced stops for contact by a movable part of the actuator, a toggle mechanism connecting said trip rod with the main valve, spring means normally retaining the toggle mechanism in position to retain the pilot valve in one and the other of two positions relatively to the main valve, spring abutments on the trip and pilot valve rods, and a single spring having ends engaging the respective abutments and adapted to be compressed when the trip rod is actuated to provide the power for shifting the toggle mechanism in opposition to said spring means for changing the relative position of the pilot and main valves in controlling admission of the pressure fluid to the actuator.

l2. ln a pump of the character described a power cylinder, a piston slidable in the power cylinder, a valve housing in connection with the power cylinder, a main pressure actuated valve slidable in the valve housing to control alternate inlet and discharge of pressure fluid to the respective ends of the power cylinder, a pilot valve p slidable relative to the main valve for controlling the actuating fluid to the main valve, a trip rod having spaced stops for contact by a part of the power piston near the respective ends of the stroke of the power piston, a toggle mechanism connecting said trip rod with the main valve, spring means normally retaining the toggle mechanism in positions to retain the pilot valve in one and the other of two positions relatively to the main valve, spring abutments on the trip and pilot valve rods, and a single spring having ends engaging the respective abutments and adapted to be compressed when the power piston engages the respective stops on the trip rod to provide the power for shitting the toggle mechanism in opposition to said spring means for changing the relative position of the pilot and main valves in controlling admission of pressure iluid to and from the respective ends of the power cylinder.

13. A pump including coaxial pump and power cylinders, pistons slidable in said cylinders, a rod interconnecting the pistons, a compensating rod at the end of the pump cylinder opposite the connecting rod to substantially equalize the pump capacities at the respective ends of the pump cylinder and cooperating with the pump piston for forming a pressure area which in conjunction with the pressure area on the connecting rod end of the power piston substantially equals the pressure area at the opposite end of the power piston, a valve housing in connection with the power cylinder, a main pressure actuated valve slidable in the valve housing to control alternate inlet and discharge of pressure iluid to the respective ends of the power cylinder, a pilot valve slidable relative to the main valve for controlling the actuating lluid to the main valve, a trip rod having spaced stops in the path of the power piston and adapted to be engaged by a part of the power piston at the respective ends of the stroke for the power piston, a toggle mechanism connecting said trip rod with the main valve, spring means normally retaining the toggle mechanism in position to retain the pilot valve in two positions relatively to the main valve, spring abutments on the trip and pilot valve rods, and a single spring having ends engaging the respective abutments and adapted to be compressed when said part of the power piston engages the respective stops on the trip rod to provide the power for shifting the toggle mechanism under action of said spring means for changing the relative position of the pilot and main valves in controlling admission of the pressure to and from the respective ends of the power cylinder.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,081,220 Coberly May 25, 1937 2,186,411 Gurley et al. Jan. 9, 1940 2,287,779 Carlisle June 20, 1942