US2950685A

US2950685A - Deep well pump reciprocator

Info

Publication number: US2950685A
Application number: US761577A
Authority: US
Inventors: Herbert M Salentine
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-09-17
Filing date: 1958-09-17
Publication date: 1960-08-30
Anticipated expiration: 1977-08-30

Description

Aug. 30, 1969 H. M. sALENTlNE DEEP WELL PUMP4 RECIPROCATOR 4 Sheets-Sheet 1 Filed Sept. 17, 1958 .lfrfrlbllllillillllllil tllllllmwl.

INVENTOR.

Aug. 30, 1960 H. M. SALENTINE 2,950,685

DEEP WELL PUMP RECIPROCATOR Filed sept. 17, 195s '4 sheets-sheet 2 s BY rroe/VEX AUS' 30, 1960 H. M. sALENTlNE 2,950,685

DEEP WELL PUMP REcIPRocAToR Filed SePt- 17, 1958 4 Sheets-Shea?l 3 JNVENTOR.

Aug' 30, 1960 H. M. SALEN-'HNE 2,950,685

DEEP WELL PUMP RECIF'ROCATOR Filed Sept. 17, 1958 4 Sheets-Sheet 4 165 ./45 .1.49 .(44 ..147 Bajg 155 (55 [43 105 j@ JM ./S J4! ab? E 1 v M M 42 [a4/xq, i 1 j Y J4 17a f 47! f 7.?

\\;\7 i ff@ Joa 16j 107 l .fee 1 j j 115 JNVENTOR. 19-25H27 M S40/WM;

United States Patent Q DEEP WELL PUMP RECIPROCATOR Herbert M. Salentine, Gardena, Calif. (269 Rocky Point Road, Palos Verdes Estates, Calif.)

Filed Sept. 17, 1958, Ser. No. 761,577

Claims. (Cl. 10S-'45) This invention relates to improvements in a hydraulic reciprocator provided at the top of an oil Well for actuating an oil pump at the bottom of the well through a string of sucker rods, an example of which is shown in my U.S. Letters Patent No. 2,803,193, issued August 20, 1957, on Long Stroke Well Pump Reciprocator.

It is an object of the present invention to provide an improved reciprocator of the type covered by said Letters Patent.

The aforesaid patented reciprocator included means for effecting a retardation of the downward movement of the piston rod as the latter approached the end of its downward stroke. I have discovered that there is substantial advantage in wells varying in depth 'to vary the period over which this retarding action takes place at the end of each down stroke of the reciprocator.

It is another object of the invention to provide such a novel reciprocator in which the vertical retarding action aforesaid may be readily adjusted to minimize tension and torque fatigue in the various functional elements of a complete pumping unit.

In the production of oil by reciprocating the plunger in a pump at the bottom of the well through a string of sucker rods, it may become necessary from time to time to adjust the vertical position of the plunger in the pump at the lower end of its stroke.

It is an object of the invention to provide such a reciprocator in which the rods may be adjusted vertically to effect a corresponding vertical adjustment of the pump plunger suspended on the lower end of said rods without dismantling said reciprocator.

As the piston rod load in a deep well pumping operation sometimes is as great as 30,000 pounds, it has been found helpful in deep well pumping to counter balance a substantial portion of this load.

lt is a still further object of the present invention to provide such a reciprocator which has embodied therewith a counter balance for a substantial portion of the piston rod load.

Still another object of the invention is to provide such a reciprocator in which said counter balance comprises a unit which can be readily added to or removed from said reciprocator, with relatively short loss of operating time in making the change.

lt is another object of the invention to provide such a reciprocator in which withdrawal of the pump tubing string is facilitated by means peirnitting this to be initiated by coupling directly onto the upper end of this string where the latter connects with the lower end of the reciprocator housing by extending a tubing section downwardly through said housing, after the reciprocator and the sticker rods have been withdrawn from the well, to make direct threaded connection with said pump tubing string. i

Another object of the invention is to provide a novel hydraulic power unit for operating such a reciprocator.

A yet further object of the invention is to provide such 2,950,585 Patented Aug. 36, 1960 a hydraulic power unit in which the upstroke and the downstroke of the reciprocator may be independently varied by simple mechanical adjustments of said power unit.

A further object of the invention is the provision of such a hydraulic power unit for operating a reciprocator in which the retardation of the down movement of the piston rod of the reciprocator, in concluding a downstroke, may be retarded over a varying period of time with said period being controlled by a simple adjustment of said power unit.

The manner of accomplishing the foregoing objects as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings, in which:

Fig. l is a diagrammatic vertical sectional view of an oil well in which a preferred embodiment of the invention is installed.

Fig. 2 is an enlarged vertical sectional View of the fluid counter balance means of the invention.

Fig. 3 is an enlarged vertical sectional View of a portion of ithe reciprocator disposed just below that shown in Fig. 2.

Fig. 4 is an enlarged vertical sectional View of a lower portion of the reciprocator of the invention disposed just below the portion shown in Fig. 3.

Fig. 5 is an enlarged cross-sectional View taken on the line 5-5 of Fig. 3.

Fig, 6 is a diagrammatic view illustrating the reciprocator of the invention during an upstroke thereof and the positions of the parts of the hydraulic power unit at this time.

Fig. 7 is a view similar to Fig. 6 showing the positions of the parts of the reeiprocator and the power unit during a downstroke of the reciprocator.

Fig. 8 is a sectional view of the hydraulic power unit valve taken on the plane of the axes of the pilot plunger and the main plunger of said valve.

9 is a cross-sectional view taken on the line 9*9 of Fig. 8.

Referring specifically to the drawings, the invention is there illustrated as embodied in a hydraulic reciprocator 15 having a hydraulic power unit i6 and a fluid counter balance 17. The reciprocator 15 is enclosed in an upper portion of the well casing l of :a well 19, said casing having a casing head Ztl at its upper end and being confined in a concrete box Z1; which is sunk in the surface 22, of the earth at the upper end of said well. The box 21 has a cover 23 which is apertured centrally to allow the coun yter balance i7 to extend upwardly therethrough.

The reciprocator l5 includes three

concentric tubes

25, 26 and 27. The tube 25 has a flange 28 welded thereto and extending radially therefrom to rest on the casing head 20 and is secured there as by bolts (not shown). At its upper end, the tube 25 has a similar flange 29 which fonns a secondary casing head for supporting a flange 30 welded `on tube 26 and secured to llange 29 by bolts or any other preferred means. Tube 26 extends a slight distance above flange 30 and has its upper end threaded to receive a stuffing box 31 having a ange 32 in which a series of bolts 33 are mounted. Extended downwardly into the stuing box 31 by bolts 34 is a gland 35 which compresses packing material in said stufling box around the tube 27. A short distance above the stutlng box 31 the tube 27 has a anve 36 welded thereto. Flange 36 is perforated in axial alignment with the holes receiving the bolts 33 in ange 32 so that these bolts also pass through ange 36 and receive nuts 37 which -adjustably relate vertically the

flanges

32 and 36.

Tube 27 extends a slight distance above ange 36 and is externally threaded to receive a bonnet 38 which is internally threaded for receiving the threaded lower end of a short tube 39, the upper end of tube 39 being externally threadedn for connection to the fluid counter balance 17 Y as will be made clear hereinafter.

The tube 25 may be referred to as the production fluid tube and is provided with a productioun uid discharge pipe 45 at a point located between the

flanges

28 and 29. The lower end of tube 25 is closed by an annular head 46 V(Fig. 4) which is welded in place within said tube and has an internal diameter suicient to freely receive the threaded upper end of a string of pump tubing 47. Resting concentrically on the head 46 is a tubing coupling 48 which is welded to said head so as to make a fluid tight union therewith 4and the lower half of said coupling is adapted to have the upper end of the pump tubing string 47 screwed thereintoV as shown in Fig. 4 so as to support said string of pump tubing on the production fluid tube 25.

The tube 26 may be referred to as the operating iud tube and is provided with an operating fluid supply line 55 which connects therewith between the flange 30 and the stufling box 31. The lower end of tube 26 is closed A by an annular head 56 inserted therein and welded in place to `form a uid tight connection with said tube. The bore of annular head 56 is threaded to receive the externally threaded base 57 by a piston rod sealing quill,

58 which extends upwardly from the base 57.

The innermost of the three main tubes of the reciprocator 15, which is tube 27, may be referred to as the cylinder of the reciprocator, and this is provided near its upper end just below the bonnet 38 with a relief line 59. Also connecting with the cylinder 27 at a point just below the flange 36 is a trigger line 60 of relatively small diameter. The lower end of cylinder 27 has an annular internal shoulder 61 with a bore 62 which is substantially smaller than thebore 63 of the cylinder 27. Slidable in the cylinder 27 is the piston 64 of the reciprocator 15 which is provided with suitable rings 65 to make a uid tight sliding t with the `bore 63 of the cylinder. The piston 64 has a downwardly extending cylindrical extension 66 which is slightly less in external diameter than the internal diameter of the bore 62 of the annular shoulder 61 at the bottom of cylinder 27. The piston 64 has a bore 67 the upper end of which is counter bored and threaded to receive a gland 68 of a stung box 69 which s 2,950,685 fe A ---l 4 webs 84 and having internally threaded

sockets

85 and 86 extending downwardly and upwardly respectively therefrom. The upper end of short tube 39 screws into socket 85 thereby supporting counter balance 17 on the reciprocator 15. The socket 86 threadedly receives the lower end of a tube 87 the upper end of which is covered by a'cap 88 screwed thereon, this cap having a relief port 89. Extending slidably through stuffing boxes 82 and 83 is a counterbalance shaft 90, the ends of which are threaded, the upper end screwing into an axial tapped hole provided therefor in a counterbalance plunger 91 having suitable rings for effecting ya close sealing engagement with the Abore 92 of tube 87. Connecting with the lower end of tube 87 is a high pressure air line 93 which leads to an air reservoir 94 in which airunder high pressure is maintained. Provided on plunger 91 and extend- 'ing axially upwardly therefrom is a threaded pulling stud 95. The lower end of shaft 90 extends into tube 39 and is connected by a threaded collar 96 to a pulling stud 97 provided on an internally threaded cap 98 which screws onto piston rod 70. It is thus seen that reciprocation of the piston 64 in the reciprocator cylinder 27 causes a similar reciprocation of the plunger 91 in the tube 87 of the fluid counterbalance 17.

The operating unit 16 of 'the invention is preferably mounted in a concrete box 99 and includes an operating oil reservoir tank 100, a motor driven operating iluid pump 101 and an automatic operating valve 102. vThe valve 102 includes a body 103 having a main plunger bore 104 and a pilot plunger bore 105. Opposite ends of bore -104 are closed by caps 106 and 4107 which are secured to the body 103 in any suitable manner as by cap screws (not shown). The opposite ends of bore 105 are closed y by

caps

108 and 109 which are secured in a similar manformsm a tight seal between the piston 64 and a piston rod v 70 which extends through the bore 67 of said piston and through said stufrihg box and has threads 75 on its upper end which receive a nut 76 which functions through a collar 77 to compress said stuing box and for-m said seal.

. The upper end of piston rod 70 extends above the nut 76 Reciprocation of the piston 64 in the cylinder 27 operates through the piston rod 70 and the string of sucker rods connected thereto to reciprocate the plunger of the pump 80 and cause a flow of oil upwardly through the string of pump tubing 47 and between the

tubes

25 and 26 to the production line 45 which conducts the production fluid to a suitable storage or transmission lines.

Theweight of the string of sucker rods through which the reciprocator 15 operates the pump 80, and the weight of the production fluid in pump tubing string 47, varies of course with the depth at which the pump 80 is located but this weight referred to as the piston rod load is sometimes considerable so that it is often times highly desirable to counter balance a substantial portion ofV this. The nid counter-balance 17, provided for this purpose, includes a double stuffing box unit 81 having aligned stuffing boxes 82 and 83 held in opposed vertically spaced relation by ner to the body 103. Suitable O-rings 110 are provided in all of the

caps

106, 107, 108 and 109 to make a fluid 'ght tit between said caps and the body 103.

Cap 107 is provided with a threaded bore 115 for receiving a stop screw 116 the position of which in the bore is xed by a set nut 117. Provided at spaced intervals along bore 104, by annular enlargement of the bore, are

pockets

120, 121, 122, 123 and 124. Screwed into -suitable tapped holes provided in the body 103 and connecting respectively with said pockets are

lines

125, 126, 127, 55 and 129 (see Figs. 8 yand 9).

Slidable in bore 104 is a main valve plunger 130 having annular channels 131, 132 and 133 turned therein at spaced intervals therealong. The portions of plunger located between said channels are ground to make a close fluid tight sealing engagement with the surface of the bore '104. The plunger 130 has axially formed

bosses

135 and 136 on its opposite ends, and is adapted to be shifted axially in bore 104 between what will hereinafter be referred to as a first position in which boss engages cap 106 and a second position in which boss 136 engages adjustable screw 116.

The cap 108 which covers one end of pilot bore 105 has a threaded bore 140 which receives a threaded screw 141 having a set nu-t 142 thereon for securing said screw in any desired adjusted position in the bore 140. Formed on the screw 141 and extending axially inwardly therefrom is a spring guide pin 143, the purpose of which will subsequently be made clear.

Slidable in the bore 105 is a pilot valve plunger 144 having

end bosses

145 and 146 formed to extend axially from opposite ends thereof and

annular recesses

147, 148 and 149 formed at successive intervals in the outer surface of the plunger. The portions of the plunger 144 the diameter of which is not thus reduced are ground to make a liquid-tight sliding t with the bore 105. Formed axially in boss 145 and extending a substantial distance into the plunger 144 is a spring receiving bore 155 into which a coiled spring 156 extends, this spring being of such `a length as to extend over the pin 143 and pressurably engage the adjustable screw 141 so as to place the E pilot plunger 144 constantly under a spring bias tending to cause the boss 146 to Contact the cap 109. This is the iirst oi two operative positions of the pilot plunger 144 in the bore 105, the second of these positions being when the pilot plunger is shifted to the left to bring the boss 145 into contact with the cap 168.

Due to the construction above described, a pressure chamber 169 is formed in the right end of the bore 105 between the cap 169 and the pilot plunger 144. A pressure chamber 161 is likewise formed in the right end of bore 194 between the cap 167 and the main valve plunger 139. ln a similar manner a pressure chamber 162 is provided in the left end ofthe bore 104 between cap 106 and the plunger 13-9.

Screwed into suitable tapped holes provided in the Valve body 103 so as to communicate respectively at all times with the annular recess 148 and pressure chamber 160 of pilot plunger 144 are main plunger actuating uid pressure line 163 and pilot plunger trigger liuid pressure line 164.

Formed by suitable connecting bores in the valve body 193 are passages 170, 171, 172 and 173. Passage 170 connects pocket 124 at all times with annular recess 149 of pilot plunger 144. Passage 171 connects pressure pocket 162 with recess 149 when plunger 144 is in its first position and with recess 148 when plunger 144 is in its second position. Passage 172 connects pressure chamber 161 with annular recess 148 of plunger 144 when the latter is in its iirst position and with recess 147 of said plunger when the latter is in its second position. Passage 173 connects pocket 120 at all times with annular recess 147 ot' pilot plunger 144.

Referring now to Figs. 6 and 7 the reciprocator actuating iluid pump 101 has an intake (not shown) which draws operating iluid from the reservoir 100 at a pointbelow the level 190 of said iiuid in said reservoir, and a. discharge line 191 which is connected by a variable pressure check valve 192 to line 127 which communicates constantly with main plunger recess 132 in valve 102. Here it is also seen that line 126 runs into line 125 and the latter terminates in the operating fluid reservoir 100. Pump discharge line 127 has a by-pass line 193 with a valve 194 providing means for loy-passing fluid discharged into line 127 back to the reservoir 100 for a purpose which will be made clear hereinafter. Line 129 leads from valve 102 to the fluid reservoir 109.

Valve actuating iiuid line 163 has a needle valve 195 and connects with the discharge line 191 of pump 101 between said pump and valve 192 so as to constantly deliver operating fluid under a controlled volume rate from the pump 191 to the annular recess 148 of the pilot plunger 144,

The valve trigger uid line 164 has a manual shut ofi valve 196 and connects to variable pressure check valves 197 and The opposite end of valve 197 connects to the line 6i) and the opposite end of valve 198 is connected by a pipe 199 to operating iiuid pressure line 55.

Operation The operation of the invention will now be described with particular reference to Fig. 6, in which the pilot and main plungers of the operating valve 102 are shown respectively in their first positions, and Fig. 7 in which said valve plungers are shown in their respective second positions. Whenever the valve pilot plunger 144 is free to respond to the spring 156 it shifts under the pressure of said spring to its rightward or rst position in the bore 105 as shot 'n Fig. 6. This normally takes place at a time when the main plunger 13) of the valve is in its second position as shown in Fig. 7. The movement of pilot plunger 144.- to its first position, as shown in Fig. 6, sets up a communication between the valve actuating uid line 163 and the pressure chamber 161 at the right end of valve bore 104. This movement of pilot plunger 144 simultaneously connects pressure chamber 162 with pocket 124 and line 129 which leads to the reservoir 100. Thus the uid in pressure chamber 162 is allowed a passage for escape therefrom at the same time that fluid under pressure is admitted to the pressure chamber 161 which rapidly shifts main valve plunger 130 from its second position to its iirst position with the boss 135 engaging the valve body cap 106.

In a similar manner when fluid under pressure is admitted through line 164 to pressure chamber 160 of the bore 105, at the right hand end of pilot plunger 144 while the latter is in its rst position, this plunger is quickly shifted leftward in bore 105, compressing spring 156 as shown in Fig. 7 to place said plunger in its second position. This movement of pilot plunger 144 connects pressure chamber 161 of the main valve plunger bore 104 with the relief line thus permitting the escape of operating uid from said pressure chamber to the reservoir tank 100, and simultaneously connects valve pressure fluid operating line .163 with the pressure chamber 162 at the opposite end of bore V104 thereby shifting main Valve plunger to its second position with the boss 136 thereof contacting the adjustable stop screw 116.

With the plungers of control valve 102 in their 'first positions as shown in Fig. 6, the discharge line 127 from pump 101 is connected with the pressure fluid reciprocator operating line 55 so that fluid is delivered under high pressure from `the pump 191 into the operating fluid conveying tube 26 and this iiuid flows upwardly under the pressure imparted theretoby said pump into the lower end of reciprocator cylinder 27, thereby exerting an upward pressure against piston 64 and causing an upward stroke of the latter.

yAs the plunger 64 arrives at the upper end of its upper stroke (Fig. 3), the lower end of this piston passes above the point where trigger iiuid line 60 connects with cylinder 27 and thereby admits fluid from said cylinder under high pressure into said trigger line. It is to be noted at this point that the variable pressure check valve 197 is normally set to respond to a substantially higher pressure than the check valve 198. It is also to be noted that the check valve .197 prevents a back flow of liuid from trigger line 164 into line 60 whereas the check valve 198 is positioned so as to permit a ow of iiuid therethrough from the `trigger line 164 to the pipe 199, which opens into operating fluid pressure line 55, but permits this flow of course only when the pressure in pipe 199 falls below the liuid pressure in trigger line 164. In the prac tical operation of the invention it has been found to produce a satisfactory operation thereof when check valve 197 is set to open at a pressure of approximately 65 p.s.i. to admit fluid from line 60 to line 164 while check valve 19S is adjusted so as to allow a ow of fluid from line 164 to line 199 when a differential in pressure of 5 p.s.i. exists between these two lines, `and when, of course, the pressure in line 164 is greater than the pressure in line 199.

The valve 196 is normally open, just as the valve 194 is normally closed, and when operating iiuid is discharged from the cylinder 27 through line 60 and valve 197 into line 164 the pressure of this iluid thus discharged is approximately equal to the fluid pressure in pressure iiuid supply line 55 which of course is transmitted through pipe .199 to the check Valve 198. Thus the fluid passing from cylinder 27 through trigger line 60 into line 164 is discharged into the uid pressure chamber 169 at the right end of pilot plunger 144 so as to rapidly shift the latter from its rst position to its second position as shown in Fig. 7. As above pointed out this results in immediate shifting of the main valve plunger 130 to its second position as shown in Fig. 7 so as to disconnect the discharge line of the pump 101 with the fluid supply pipe 55, connect the discharge line 127 of the pump to the reservoir return line 126 and likewise connect the pressure iluid supply line 55 with the reservoir return line 129.

Y Y This releases the space within the cylinder 27 beneath the piston 64 of `any applied pressure from the pump 101 and allows the piston 64Yto descend underthe action of the weight of Vthe uncounterbalanced portion of the weight of the piston rod load imposed on said piston to expel the pressure fluid beneath said piston and from the lower end of the cylinder 27. This constitutes a downstroke of the piston 64 and is accomplished entirely under the iniluence of gravity. Normally the space in the cylinder 27 above the piston 64 is filled with air and as the space in the cylinder above the piston 64 increases with the downstroke air is supplied to the upperl end of the cylinder through the return line 59. Y

The approach of piston 64 to the bottom of its downstroke causes the cylindrical extension 660i the piston to enterthe reduced bore 62 provided Vat the .lower end of the cylinder 27 so as to trap fluid between the piston 64 and the inward extension 61 forming said restricted bore. There is enough space, of course, between the eX- tension 66 and the bore 62 so that the entrapment of uid above mentioned is not absolute and merely acts as a dampener or retarder decelerating the rate of down@ ward travel of the piston 64 and thus cushioning the effect of the change of direction of the piston on the sucker rod suspended from the piston rod 7d.

As the descent of piston 64 is thus decelerated the pressure set up in the line 55 by the rapid expulsion of the liquid from that portion of the cylinder 27 beneath the piston 64, during the downstroke of the latter, is greatly reduced. While the piston 64 was descending relatively freely in the cylinder 27 during the downstroke of the piston, the pressure thus produced in the supply line 55 and transmitted from this through the pipe 199 to the check valve v19% was in excess of the pressure of the lluid conned in trigger line 164 and pressure chamber 160. Entry of projection 66 into the restricted bore 62 at the lower end of cylinder 27, however, gradually reduces the iuid pressure in line^55 and pipe 199 to a point where this pressure is inadequate to prevent a flow of liquid from the trigger line 164 through the valve 198 thereby permitting the pilot plunger 144 to respond to the compression set up by spring 156 and travel to the right, into the first position of saidV pilot plunger as shown in Fig. 6.

The gradual reduction of pressure in the line 55 as the piston 64 is decelerated at the lower end of its downstroke provides an opportunity for determining the point in said deceleration at which the downstroke of the piston 64 will be halted and a subsequent upstroke started by delivery of fluid under pressure beneath said piston. This opportunity is afforded by the adjustment provided on the valve 102 by the screw v141 acting'on the spring 156 to vary the pressure applied bythe latter to the pilot plunger 144.

By screwing this screwV 141 outwardly from the threaded bore 1'40 of the valve, the pressure applied by the spring 156 to the pilot plunger 144 is reduced so that the iud in the trigger line 164 isV coniined therein at a relatively low pressure. Thus thevactuation of the pilot plunger 144 so as to start an upstroke ofthe piston 64 will occur a substantial period of time later than it would prior to such adjustment. By this means it is possible to control the extent to whichrdeceleration has taken place in the downward movement of the piston 64 at the time that uid under 'pressure is admitted beneath this piston so as to halt the downward movementl of this and start an upward stroke of the piston.

The counter balance 17 of the invention has a number of important novel features including the simple manner in which it is associated with the reciprocator so that yit can berfadded to or removed from the reciprocator with relatively short loss in operating'rtime and, Awhile in use, may be adjusted by .variationof the air pressure supplied thereto through. the pipe 93 so as to counter balance any desired portion of the piston rod load carried by the reciprocator. the counter balance 17 is shown united with the reciprocator 15, and the removal of the counter balance is preferably accomplished in the following manner: The operationof the reciprocator 15 is halted with the piston 64 at the endy of an upstroke by closing the trigger line valve 196A sometime during said upstroke and halting the pump 161 after this ups-troke is completed. The closing of valve 196 prevents iluid passing through trig-` gertline -164 to the valve 182 so as to change the valve plungers from their rst positions as shown in Fig. 6. Thus at the end of the upstroke just mentioned, the uid supply line 55V remains connected with the discharge line 127 of the pump 191 and reverse ow of operating oil through line 127 being prevented by check valve 192,. the piston 64 is retained in its upwardrncst posi-V tion until some change is made in the operating apparatus. YThe location of the piston 64 in the reciprocator 15 when thus halted is illustrated in Fig. 3 of the drawings. The cap 88 'may now be removed and a hoisting iitting screwed onto the pull stud 95 on the top of counter balance plunger 91 and the weight of the piston rod load transferred to the rigging of a derrich mounted over the well 19. Such a derrick of course may be provided temporarily for the perfomance of this particular operation and then removed when the operation is com-` pleted.

The disassembly of the counter balance from the reciprocator 15 may be accomplished in any of several different ways such as removing bolts (not shown) whichl connect the anges embodied in the receptacle 35 of the double stuing box 81 or on the other hand this disassembly mightV be performed by unscrewing tube 39 from the bonnet 38 so that this tubeand the counter balance 17 might be lifted upwardly to uncover the lower end of the counter balance shaft 90. When this has been done the shaft 90 may be disconnected from the piston rod 70 by unscrewing the collar 96 from the pull stud 97 on the upper end of the piston 64.

When' this has been done, the tube 39 may be unscrewed lfrom the lowermost receptacle 85 of the counter balance 17 'and this tube screwed back into the bonnet 38, after which the cap 88 may be unscrewed from the upper end of the counter balance 17 and screwed onto the upper end of tube 39 which is of the same diameter and has like'threads as the counter balance tube 87.

The installation of `a counter balance 17 in association with the reciprocator 15 as shown in the drawings is of course `accomplished by an exact reverse of the above described process of removing the counter balance.

As soon as the steps involved in adding the counter balance 17 or removing the same from the reciprocator '15 yare nished, the operationV of the reciprocator 15 may be resumed at once by merely starting the operating liquid pump 101 and opening the trigger line valve 196. The starting of the pump will build up any diminished uid pressure inthe cylinder 27 beneath the pist-on 64 so as to boost this to its uppermost Vposition in which the trigger line 60 is exposed and receives liquid under pressure from beneath the piston and this condition of course, coupled with the opening of valve 196 immediately delivers operating liquid under high pressure through the trigger line 164 to the right hand end of pilot plunger 144 which results in the rapid switching of the two valve plungers to their respective second positions and the initiation of a downstroke in the operation of the invention. From this Vpoint on, the

.reciprocation of the reciprocator 15 is resumed so as to occur automatically in the manner already described. Another important advantage possessed by the present invention is 4the facility which it affords for adjusting the vertical limits within which the plunger (not shown) of the deep well pump is reciprocated during the pumping of oil by said pump. Two dijerent ways are provided in the present invention for accomplishing this As .disclosed herein,

function. In the rst and simplest of these methods, the cylinder 27 of the reciprocator itself is vertically adjusted in relation to the tube 26 on which said cylinder is supported by the bolts 33 (Fig. 3). This adjustment is effected by a balanced manipulation of the nuts 37 on the various bolts 33 which support flange 36 from flange 32 so that the flange 36 is elevated or lowered with respect to flange 32 by the net operation. The vertical adjustment of reciprocator cylinder 27 in this manner varies the upper and lower limits of travel of the piston 64 of said reciprocator and where there is no change made in the aggregate length of the piston rod 79 and the string of sucker rods attached thereto, this adjustment thus makes a like change in the upper and lower limits over which the plunger reciprocates in the pump 80.

One advantage of this method of adjustment is that it may be accomplished even while the reciprocator is operating.

The other method afforded by `the invention for accomplishing this particular adjustment is embodied in the manner of attaching the upper end of piston rod 70 to piston 64 and this method involves removing the tubing 39 from the bonnet 38 by unscrewing this tubing and hfting it and the counter balance 17, if the latter is in place, upwardly to expose the nut 76 and permit this to be rotated so as to engage the threads 75 and either raise or lower the piston rod 70 and the string of sucker rods suspended therefrom relative to the piston 64. In preparation for making the latter adjustment of course the operation of the reciprocator 15 must be halted in the manner above described with the piston 64 temporarily stationary in its upwardmost position as shown in Fig. 3.

Provision is also made in the present invention for the ready withdrawal of the string of pump tubing 47 from the well 19 after the reciprocator 15 has been re` moved from the well along with the piston rod 70 and the string of sucker rods and deep well pump plunger suspended therefrom. When these preliminary steps of removing the pumping system from the well have been accomplished, the tubing 25, pump tubing string 47 and deep well pump Sii alone remain mounted in the casing 1S and are supported on the casing head 20 of the latter.

To remove the production tube 25 of the reciprocator 15 and the uppermost section of the string of pump tubing 47, a section of pump tubing is inserted downwardly from the rigging mounted over the well and into the tube 25 and the lower threaded end of this section is screwed into the upper internally threaded half of the coupling 4S. The last mentioned section of tubing is then lifted to remove the tube 25 and the uppermost section of the pump tubing string 47 until the coupling at the lower end of said section appears above the casing head 2t) and may be supported by blocks provided therebeneath. From this point the disassembly and removal section by section of the string of pump tubing 47 may proceed in the normal manner.

The present invention also provides a novel means of varying not only the length but the time consumed in the upstroke and downstroke of the reciprocator 15. This is accomplished by adjustment of the needle valve 195 so as to vary the volume of operating liquid delivered through the line 163 to the annular recess 148 of the pilot plunger 144 of the valve 102. Variation in this manner of the rate of delivery of operating liquid to the pilot plunger 144 through pipe 163 varies the time period required for this operating liquid to respond to a change of position in the pilot plunger 144 by effecting a similar change in the position of the main valve plunger 139. lt is manifest that a very slight change in this period will effect a corresponding delay in the starting or" the upstroke of the piston 64 of the reciprocator as well as a starting of the downstroke of said piston. Thus the time period of both the upstroke and the downstroke of piston 1G 64 of the reciprocator may be materially modified by manipulation of the needle valve 195.

The by-pass line 193 and valve 194 are provided for convenience when it is desired to lower the reciprocator plunger 64 in the cylinder 24 during a time when the pump 101 is shut down. This valve may also be employed while the pump 101 is operating to effect a manually controlled movement of the piston 64 in the cylinder 27, for whatever purpose this might be desired.

The claims are:

l. In a reciprocator for actuating the plunger of a pump in an oil well through a string of sucker rods, the combination of: a cylinder; a piston in said cylinder; a piston rod secured to said piston, and extending downwardly therefrom; seal means at the lower end of said cylinder through which said rod slidably extends, said rod yconnecting with said sucker rod string below said seal means; passage means for delivering operating fluid to the lower end portion of said cylinder to produce an up stroke of said piston and to discharge said fluid from said cylinder during a downstroke of said piston; fluid actuated piston descent retarding means including inter-related elements on the lower end of said piston and in the lower portion of said cylinder which retard the discharge of operating fluid through said passage means when said elements are brought into overlapping relation by a down stroke of said piston thereby progressively decreasing the pressure with which fluid is discharged from said cylinder through said passage means; means operative in response to a critical pressure being reached in the fluid being discharged through said passage means during the concluding portion of a down stroke of said piston to cause fluid to be delivered under relatively high pressure into said cylinder beneath said piston to start an up stroke of said piston; and means for adjusting said pressure responsive means to determine the value of the critical pressure to which said pressure responsive means responds.

2. In a hydraulic reciprocator for actuating a pump in an oil well through a string of sucker rods, the combination of: a cylinder supported at the upper end of said well; a piston slidable in said cylinder; a piston rod connected at its upper end with said piston and at its lower end with said string of sucker rods; means on said piston and the lower portion of said cylinder for trapping uid as said piston approaches the lower end of its downstroke for decelerating the downward movement of said piston, piston rod and string of sucker rods; an operating uid reservoir; an operating fluid pump Withdrawing fluid from said reservoir; means for delivering fluid discharged from said operating 'fluid pump to the lower end of said cylinder; a control valve interposed in said fluid delivery means, said control valve including a main plunger having first and second positions and a pilot plunger having first and second positions, said main plunger in its first position connecting said operating fluid pump discharge with the lower end of said Cylinder and in its second position connecting the discharge of said operating uid pump with said reservoir and connecting the lower end of said cylinder with said reservoir, said pilot plunger in its first position directing fluid from said operating fluid pump to one end of said main plunger to move the latter into its vfirst position, said pilot plunger in its second position directing iluid to the opposite end of said main plunger to move the latter to its second position, a trigger line leading from an upper portion of said cylinder just below said piston when it reaches the top of its upstroke to conduct operating iluid from said cylinder to one end of said pilot plunger to shift the latter to its second position; adjustable spring means bearing against said pilot plunger to spring bias the same towards its first position; and valve means responsive to the decrease in pressure of operating uid expelled from the lower end of said cylinder during the downstroke of said piston which takes place, when der starts the upstroke of said piston.

3. In a hydraulic reciprocator for actuating the plunger of a pump in a deep well through a string of sucker rods, the combination of: a cylinder; a piston in said cylinder; a piston rod provided on said piston and extending downwardly therefrom to connect with said sucker rod; means for automatically delivering uid beneath said piston into the lower endrof said cylinder to cause an upstroke of' said piston and then permitting said uid to be exhaustedV from beneath said piston to permit a downstroke of the latter; a casing head at the upper end of said well; stut-v ng box means on said casing head admitting said cylinder axially through said casing head and making a uidY tight seal therewith; and adjustable means for mountingY said cylinder on said casing head whereby the elevation of said cylinder may be altered to adjust the upper and lower limits of travel of said sucker rod string in the reciprocation thereof'by said reciprocator.

4. In a hydraulic reciprocator for actuating the plunger of a pump in a deep well through a string of sucker rods, the combination of: a cylinder; a piston in said cylinder; a piston rod provided to extend slidably through said piston and downwardly therefrom to connect withV said sucker rod; means for'automatically delivering fluid beneath said piston into the lower end of said cylinder to cause an upstroke of said piston and then permitting said uid to be exhausted from beneath said piston to permit a downstroke of the latter; a casing head at the upper end of said well; means for mounting said cylinder on said casing head; nut means screwed onto said rod above said piston for supporting said rod von said pistonand forkvertically adjusting said piston rod rela-` tive to said piston; and means for haltingthe operation of said pistonreciprocating means with said piston in its uppermost position to permit actuation' of said piston rod adjustment means. 'L f 5. In a hydraulic reciprocator for actuating the plunger of a pump in an oil well through a string of sucker rods, the `combination of: a cylinder; a piston slidable therein; a piston rod connected at its upper end Vto said piston and at its lower end to said string of sticker rods; an operating uid tube concentrically surrounding said cylinder; a uid tight seal means provided in the lower end of said tube through which said piston rod is slidable; a production iiuid tube concentrically surrounding said operating uid tube; means forming a head in the lower end of said production fluid tube having a central aperture therein about which is providedwa threaded production tubing coupling for` making a threaded connection with the upper end of a string of production tubing extending downwardly therefrom to said pump, and

, threaded means on said head disposed above the upper end of said Ystring of production tubing for engagement by an element inserted downwardly through said production uid tube after said cylinder, piston, operating uid tube, piston rod, and string of sucker rods have been removed from within said production uid tube and said string of production tubing, to start the withdrawal upward of said string of production tubing from said well; and means for supporting said cylinder said operating fluid tube and s'aid production iiuid tube at the upper end of said well.

References Cited inthe tile of this patent UNITED STATES PATENTS 1,636,001- Kasley `Tuly 19, 1927 2,699,154 Smith Ian. 11, 1955 2,703,557 Polki Mar. 8, 1955 2,729,941 Rose et al Ian. 10, 1956 2,803,193 Salentine Aug. 20, 1957 2,838,910 Bacchi June 17, 1958