US2287709A

US2287709A - Hydraulic well pumping mechanism

Info

Publication number: US2287709A
Application number: US316323A
Authority: US
Inventors: Louis A Ringman
Original assignee: Nat Supply Co
Current assignee: National Supply Co
Priority date: 1940-01-30
Filing date: 1940-01-30
Publication date: 1942-06-23
Anticipated expiration: 1959-06-23

Description

June 23, 1942. L. A. RINGMAN HYDRAULIC WELL PUMPING MECHANISM Filed Jan 30, 1940 7 Sheets-Sheet 1 IN VENTOR.

XM 1 7? WM,

' ATTORNEY.

June 23, 1942.

L. A. RINGMAN HYDRAULIC WELL PUMPING MECHANISM "7 Sheets-Sheet 2 Filed Jan. 50, 1940 IN VENT OR.

-44, ATTOR EY.

June 23, 1942. 1.. A. RINGMAN HYDRAULIC WELL PUMPING MECHANISM Filed Jan. so, 1940 7 Sheets-Sheet 3 INVENTOR. Z H P 5, BX/M4 M- M ATTORNEY.

June 23, 1942.. L. A. RINGMAN 2,237,709

' HYDRAULIC-WELL PUMPING MECHANISM Filed Jan. 50, 1940 u '7 Sheets-Sheet 4 IN VE NTOR.

J1me 1942- Q L. A. FIQINGMAN HYDRAULIC WELL' PUMPING MECHANI SM Filed Jan. 30, '1940 7 Sheets-Sheet 5 X I. PINVENTOR. BY

1 ATTORNEY.

I June 23, 1942..

L. A. RINGMAN HYDRAULIC WELL PUMPING MECHANISM Filed Jan. so, 1940 lZO 45- 7 Sheets-Sheet 6 INVENTOR fl, BY;

W ATTORNEY June 23, 1942. RlNGMAN 2,287,709

HYDRAULIC WELL PUMPING MECHANISM Filed Jan. 50, 1940 7 Sheets-Sheet '1 127 ;&5 125 125 .zzs JEkb .117 ,l 127 I 127.

INVENTOR BY W TTORNEY Patented June 23, 1942 nrnanumc WELL PUMPING MECHANISM-4 Louis A. Bingman, Toledo, Ohio, asslgnor to The v National Supply Company, Pittsburgh, Pa., a corporation of Pennsylvania Application January to, 1940, Serial No. 316.323

3 Claims.

This invention relates generally to a hydraulic pump and more particularly to a hydraulic mechanism for pumping wells.

Another object of vision of a fully hydraulically controlled pumping mechanism.

Another object is the provision of a fluid operated and controlled pumper which is iully automatic. I

Another object is the provision of a fluid this invention is the prooperated and controlled well pumper which utilizes the well load for operating the pump piston in onedirection.

Another object is the provision of a fluid controlled pumping mechanism capable of being automatically operated through any one of a series of selected strokes.

Another object is the provision oi'a fluid controlled pumper operated by a fluid pressure.

Another object is the provision of a fluid pumping mechanism wherein the stroke and the motion of the pumper are operated by the same working fluid.

Another object is the provision of means for controlling the descending movement of the pumper piston.

hydraulic pumping mechanism similar to that shown in Fig. 2 with the operating control mechanism housed in a single casing. The control in this instance is .set at the idle position with the pump piston at the lower end of the cylinder. p

Fig. 4 is a view similar to Fig. 3 illustrating the position of the controls during the upstroke oi the pump piston for a. selected stroke length.

Fig. 5 is a view similar to Fig. 4 illustrating the reversal of the control mechanism to check the'ascent of the pump piston and to causeit to descend from the top of the selected stroke. Fig. 6 is a view similar to Fig. 5 showing the position of the controls during the time the pump piston is descending and illustrating how its motion is retarded.

Fig. 'l is a view similarto Fig. 6 illustrating the automatic operation 01 the control mechanism for decelerating and finally stopping the piston at the lower end or the selected stroke just prior to its reversal, the control valve appreaching theposition similar to that shown in Another object is the provision of means for I "decelerating the'piston'to a stop at the bottom oi its stroke.

Another, object is' the provision of a fully hydraulic pumping mechanism which is selfcontained, having no atmosphere.

Another object is communication with the the provision of afully sellconta'ined hydraulic pumping system. capable of circulating the working liquid during the idling and downstroke periods and when excessive pressures build up within the system.

Another object is the provision of new and improved structural apparatus making up a V trols set for moving the pump piston to the top Fig. 4, thus representing a complete cycle of the operation of the pump piston.

Fig. 8 is a view similar to Fig. 3 with the conof the cylinder without reversing the movement of the piston, thereby causing the relief valve to function due to the development ofv an ex cessive fluid pressure in the system.

Fig. 9 is aside elevation of an actual pumping unit showing the pump and reservoir con- 1 nectedthereto. Fig. 10 is a diagrammatic-view of a complete pneumatically operated pumping mechanism.

,Fig. 11 is an enlarged sectional view of the hydraulic pumper and the method of operating the same.

Other objects andadvantages appear in the following description and claims.

In the accompanying drawings a I practicalr I embodiment illustrating the principles. or this invention. is shown wherein:

Fig. l is a diagrammatic view of a-hydraulic pumping mechanism showing a simplified control mechanism comprisingthis invention.

Fig. 2 is a viewsimilar to that shown in Fig. 1

with the provision of additional means for obtaining different stroke lengthsof the pump piston and for decelerating the movement piston at the lower end oi the down stroke.

top of the pump cylinder shown in Fig. 10.

Fig. 12 is a diagrammatic view illustrating a battery. of fluid operated pumping mechanisms actuated from acommon source of fluid pressure pp y- Fig. 1a shows a horizontally disposed fluid pumping mechanism arranged to operate a plurality of pumping jacks.

Referring to Fig. 1 of the drawings, lli'represents a well casing which is closed at its upper end by the well casing head It having a centrally disposed opening therein arranged to carry slips or other suitable means for receiving the well tubing l2 forming the pump barrel within the well.

Fig.8 is a diagrammatic view of a complete This tubing is suitably packed to pre-.- vent the escape .of fluid under pressure from the well. A-tubing adapter i3 is secured to the IB preferably welded to the lower end thereof for securing the same in an annular seat or shoulder I9 of the adapter. The latter is provided with a dashpot chamber below theopen end of the cylinder I5. p

The upper end of the cylinder I5 is enclosed by the ,cap 2! secured by bolts to an annular flange 22 welded or otherwise fastened to the cylinder. the eye 23 for hoisting the pump as a unit. A shoulder 24 is provided in the bore of the cap defining a chamber thereabove.

The motor piston 25 is arranged to reciprocate within the cylinder I5 and has secured thereto the polish rod 26 which extends down through the packings held by the glands I 6 and I7 and into the tubing l2 where it is fitted with a suitable pump plunger. It will be noted from the drawings that the shoulder 24 and the bottom of the dashpot chamber 20 are engaged by the piston 25, thereby determining the limitin position of the piston in the cylinder and these limits are obviously determined by thelength of the cylinder I5.

The valves which control theoperation of the j motor piston are shown in their simplest form in Fig. 1' wherein 28 represents the pilot valve spool slidably supported in the valve chamber .28, and 30 represents the master valve spool operated by a suitable prime mover as indicated by the motor 35. The .working liquid is contained in the sump or reservoir 38 which is provided with two compartments formed by the dividing wall 11. The liquid is withdrawn from the compartment 38 and received upon its,return from 'the' system into compartment 40-. Thus any foreign matter carried back to the reservoir is retained in compartment 40 by the dividing wall and may be removed through-a, suitable sludge opening not shown. v

The liquid is withdrawn from the compartment 3801" the reservoir through the line' I I to the pump 34 where it is forced under pressure through the line", the relief valve 43, the line 44, to the recess in the chamber ll of the master valve 30, whence it passes to recess 46; line" to the dashpot'20 below the piston25 in,

The top of the cap is provided with tains the master valve spool 30 in the extreme position at the left of the chamber.

Any'liquid that may have been trapped between the left end of the master valve spool 30 and the chamber 3| is forced out by the movement of the spool through the line 53, to the recess 54 in the chamber 29 of the pilot valve and continues through the recess 55, the line 56, the recess 51 in the master valve chamber 3i, the line 58 to the common return line 60 leading back to the compartment 40 of the reservoir 36. This circuit is of course not subjected to pressure at this time. I

A line 6i connects the pressure relief valve 43 to this common return line 60 for by-passing the liquid if the pressure in the system reaches a predetermined maximum.

When the lower edge of the piston 25 has passed above the line 62 opening into the cylinder I5 adjacent its upper end, the liquid under pressure within the cylinderpasses through line 62, the check valve 63, line 64 to' the chamber 29 of the pilot valve at the left end thereof. The pressure on the liquid causes the pilot valve spool 28 to move to the right, compressing the spring 32 as shown in Fig. 2. 7,

When the pilot valve spool' 28 is moved to the right the liquid under 'pressure travels from recess 46 through line 48, recess in the pilot valve chamber 29, thence to recess 54, line 53, to the master valve chamber 3| and'works against the left end of the master valve spool 30, causing it to move to the right.

Any liquid trapped between the right end of the master valve spool 30 and the chamber 3| is forced out through line 52; recess 5i in the pilot valve chamber 29. thence to recess 65, line 66, recess 61 in chamber 31 to the common return line and back to compartment 40' of the reservoir 36. g I

When the master valve spool 30 has been moved to the right as shown in Fig. 2 the liquid under pressure travels from the recess 45 in the cylinder I5. thereby lifting the piston 25 to actuate the polish rod on its: upstroke lifting the well loadr The liqu idv under pressure also passes from the recess 46 through the line 48 to the recess 50 in the chamber '29. of thepilotvalvewhere it continues through theirecess 5|, the line 52 to the master: valve chamber (at the'right end thereon. The pressure -,oi the liquid ,thus mainchamber 3| to recess 51 and thence through line 58 to the common return line 60. Thus the master valve spool having been reversed after the' piston 25 is raised above line 62 in the cylinder I5, by-passes the liquid to the reservoir. The

liquid thus circulates freely in this circuit while the piston 25 descends. I

The liquid in the cylinder I5 below the piston :25 is expelled from the cylinder I5 by the weight of the piston, polish rod and parts fastened thereto plus the liquid carried thereby within the well tubing. The expelled liquid from cylinder I5 passes through the dashpot 20, line 41, recess 46 in chamber 3|, to rece'sst'l, and thence through the common-return line 60 to the reservoir. The beveled surface on the spool 30 throttles the liquid'passing therethrough from This throttling action recess 46 to recess 61. limits the speed of the movement of the piston 25 during its downward'stroke'. This throttling action may be changed by the screw flg'thereby providing an external adJustment"of'the open ing between'the beveled 30' toretain it in the reversed position? against the leftendof the master-valve spool:

When the piston 2B desc'ends it creates a partial vacuum thereabove.

As the upper'edge ofthe piston 2lpasses' be surfacell'and the chain ber 31 to regulate the speed of thefdown' stroke The liquid being discharged from the cylinder' aas'moe- 1 The flexibility in low the line I opening into the cylinder 15nd- ;Iacent the lower end thereof, the partial vacuum above the piston draws the liquid from the left end of the pilot chamber 29 through line 54.

line '|l,check valve 12, line 19 to the space above the piston 25 in the cylinder l5. The spring 32 also aids in moving the liquid in this circuit. However the spring 32 could not move the pilot valve. spool 28 until pressure was relieved from line I9.

After the pilot valve spool 25 has been returned to the position shown in Fig. 1, the liquid in the left end of the master valve chamber 3| is vented through the line 53, recesses 54 and- 55 in the pilot valve chamber 29, line 55, recess 51 in the master valve chamber 3|, line 53, the

the application of this system isobvious... v In addition to the newly added stroke control lines, Fig. 2 also shows an added control for regulating the speed of the movement oi the master 'valve spool 25 in'traveling from right to left which action determines the deceleration of the piston 25 at the end of the down stroke 'by retarding the flow of the liquid from the cylinder l5 between the recesses 45 and 51. If

the beveled section 58 cuts of! this flow abruptly by sliding over the land section between these recesses the piston'would stop suddenly, producing a shock. To avoid this shock a tapered throttle screw 50 is provided in the left 'end of y the master valve casing to restrict the passage common retum line 50 back to compartment 40 r sufllcient pressure on the liquid forced out of the cylinder by the piston 25 to move the master valve spool 39 to the left into the position shown in Fig. 1.

This description completes a full operating cycle of thehydraulic pump. It will be noted however that when the piston 25 passed below lines 52 and some of the operating liquid passed into the cylinder l5above the piston 25. When the liquid accumulates sumciently to spill out the line 13 with the piston at the top of its stroke it passes down through check valve 14, line 15 to the' common return line 59 to the reservoir- It will benoted that this pumping mechanism is entirely. hydraulically controlled and operated. The hydraulic system is self-contained.

and has no communication with the atmosphere, which precludes the possibility of sand or water vapor entering the system.

The pilot valve spool serves only to control the position of the master valve spool which in turn controls the direction of the flow 'of liq-' uid under pressure, thereby controlling the direction of the movement of the piston and the rate of speed that the piston descends, which is adjustable by means of the screw- 33.

Referring now to Fig. 2 it will be' noted that additional stroke control lines 15 and I1 have been added and they enter the cylinder 15 at positions intermediate the

stroke control lines

52 and 10. Valve 18 connects either

stroke control line

52 or 15 with the check valve 53 through the line 59, andvalve 19 connects either stroke control line 10 or Tl with check valve 12 through the line 59. Thus by selecting the proper stroke control lines vwiththe

stroke control valves

18 and 19 the piston 25 may be made to operate in any. one of four strokes such as controlled by

lines

52 and 19, 52 and 11,15 and Ill or 15 and 11.

?If the distance between the entry of lines 52 .and

of the fluid therefrom. Thus the smaller the orifice the slower the movement of thespool 30 to the left resulting in gradually stopping the flow of liquid from the cylinder l5, thereby grad ually decelerating and finally stopping the down- 15 into cylinder" l5 is different than the dis- 'tance between the entry of'

lines

10 and 11, then each of the four strokes will be, of different lengths. In this manner any number .of stroke control lines may be added to produce any length of stroke desired. Again several of these stroke control lines may be added at one end of the cylinder l5with only one stroke line at the other.

ward'movement of the piston 25.

A small leakage hole 89' is provided in the throttle screw 85 to prevent stalling of the master valve spool in case one happened to turn the r tapered screw completely into theopening.

A check valve 8| is arranged to by-pass the needle throttle valve 80 to permit the master valve spool 30 to be quickly shifted to the right when the piston isat the top of its stroke and is about to reverse.

In Fig. 1 the structure is shown in its simplest form to demonstrate the principles of this invention. In Fig. 2 the stroke control, and the piston decelerating mechanisms have been added to illustrate the complete invention. However in these two views the relief valve, the pilot and master valves. the stroke control valves and the various check valves have been shown as separate or individual structures. Each of these structures has been combined-in Figs. 3 to 8 into a single housing 82 which in practice is secured to one side of the cylinder anchor and the line connections running to the various levels of the cylinder'lS may be'made by small copper lines as illustrated in Fig. 9. The lines are enclosed in the long box or conduit 83 extending up one side of the cylinder l5 and the lines 42 and 50 connecting the pump and the reservoir with the housing 92 may be flexible hose connections to prevent vibration from 'being transmitted between these two parts of the mechanism. The pump and the reservoir have been combined into one housing as illustrated at Blkwhich is se- I cured to the same baseas the motor 35.

Referring now to Figs. 3 to 8, the

stroke control valves

19 and 19 are shown as cylindrical plugs rotatably mounted in a common chamber 85. and having radial ports, disposed in angular relation to each other, andwhich connect with a common passage in the center of thelplugsrep resenting a portion of the lines 59 and 59 respect vely as previously described relative to Fig. 2. For convenience the radial passages in the cylindrical plugs of the

valves

18 and 19 are disposed at ninety degree positions.- However the more.

control lines added may necessitate reduction of this angular spacing.

Each

valve

15 and 19 is provided with a stem having an indicating dial secured thereto as shown at'35 and 91. These dialsare marked as shown in Fig. 2. The

numbers

52 and 15 on dial 35 indicate selection of the stroke control lines of the same number at the top of the piston stroke made by turning this dial. The dial 3! thereon. a

bottom of the piston stroke. In actual practice the. stroke, positions -or lengths may be stamped A valvedr ain i'gedines: opens into the chamher as between ,theplugs of the valves is and 1s andconnectswiththerecess 65 in the pilot valve control chamber 29. andthus passes directly to the common return line 50.

The

casing

12,15 also providedwith a drainage p line as connecting the right end or the 'pilot valve chamber 29 with'the line 96'. thence to the com- .mon return line 69 to avoidtrapping any liquid that may leak pa spool valve 29.

The master valve spoolspring 99, which is supported on the abutment screw 33, is provided st the last abutment of the pilot to cause leftward motion of the master valve spool incase the reversing action of the spool is so slow that the piston 25 reaches the bottom of the dashpot20 before the spool is in position for the upward stroke, at which time the deficiency in the discharge pressure of the liquid below the pistonis compensated by the force of the spring 99. v

The relief valve 43 shown in detail in Figs. 3 to 8 is made'spool-shape similar to the pilot and master valves. This valve is held to the left by the spring 9| which may be adjusted by the screw 92 to obtain a predetermined pressure on the spool, causing it to function as a safety device to protect the system from excessive pressures. when the pressure of the system exceeds the predetermined amount as set by the loading of the springthe liquid under pressure becomes effec- 4 tive against the differential piston 93 at the left of the spool 43 through the line 94 connected to the main line 42. The small differential-piston 93 maybe omitted if desired. The spool 43 is then moved to theright against the pressure of the spring 9| and the liquid under pressure is b'y-passed from the recess 95 to the recess 95, which is represented by the line 6| in Figs. 1 and 2. .A drainage line 91 is provided for the right endof the spool valve" toprevent trapping of any liquid that may have leaked past the valve. Excessive pressures may occur when one fails to properly set dial 96 and the piston 25 reaches the top of its stroke as indicated in Fig.8, or at any point of theupstroke where the load of the polish rod is excessive, such as may be encountered'when awell sands up.

Again referring to-Fig. 3 a. line 99 is shown connecting the line '41, adjacent the dashpot 29 in the adapter i 3, with a radial opening in the stroke control plug valve 19 leading .to the line 69. check valve 93, line 94 to the left end of the pilot valve chamber 29. This line 99 is connected onlywhen the dial 9515 set at the idling position,

the recess,45 to the recess 51 and thence through the line 59 to the common return line 60. The

lines

16 and 11 respectively as shown in Fig. 4

' the pressure of the working fluid formerly effective through the line 99 on the left end of the pilot valve spool 29 is cut off by therotation of the dial and at the same time line" is cut into the circuit but there is no pressure in this line or above the piston 25. The spring 32 thus forces the pilot valve spool 29 to the left, pushing the working liquid out of the chamber 29, through line 64, line IL-check valve 12, line 59, stroke control valve 19, line H to the cylinder I5 above the piston 25.

Themovement of the pilot valve spool 29 connects the left end of the master valve chamber II with the common retum and admits the working liquid under pressure to the 'right end of the master valve spool 39, thereby moving it to the left. When the recess 45 is cut off from the recess 51, the pressure of the working fluid builds up sufiicient force tolift the piston 25 onits upward 1 under pressure to the left end of the pilot valve chamber 29 moving the pilot valve spool 29 to the right, thereby admitting liquid under pressure to the left end of the master valve chamber 9|, moving the master valve spool 90 to'the right while connecting the right end of the master valve chamber to the common return line 99. The illustration in Fig. 5 shows the master valve spool just about to open the by-pass between recesses 45 and 51 and close the connection between recesses 45 and 49.

Any excess liquid in the cylinder l5 above the piston 25 will at this time be drained of! through the line 13, check valve I4 and on to the common return 69.

The master valve spool continues to move to the right until it reaches the position shown in .Fig. 6. The working liquid is then completely by-passed to'the common return 59 and the liquid from the cylinder I5 is being forced through the line 41, recess 49, past the beveled surface 89 of the valve, recess 61 to the common return 99 with the pressure thereon'being effective on the left end of the master valve spool 39 to maintain it to the right in the position shown.

After the piston clears the stroke control line 11 in, the cylinder l5 on its downward stroke as shown in Fig. 7 the liquid formerly trapped at the left end' of the pilot valve spool 29 and holding it to the right is drawn back into the cylinder l5 through the line 11 because of the partial vacuum therein and because of the force exerted by the pilot valve spring 32. I

Thus the pilot valve spool 29 moves to the left as shown in Fig. "7, thereby connecting the i left end of the master valve cylinder 3| with'the working liquid is also effective through the recess 49 of the master valve, the line 49, the recesses 59 and 54 of the pilot valve, the line,

. the check valvell tothe left end of the master valve chamber 3| and thus being effective to forcevthe master valve spoolto the right compressingfthe spring '99..

when the dials99 and 91 are set to connect common return 99 and connecting the liquid discharged from the cylinder 15 to the right end of the master valve chamber 3| to aid in moving the master valve spool 90 to the left. The movement of this valve toward the left end of the chamber is of eourse impeded by the restricted flow past the needle valve 99, which action gradually cuts off the flow of the liquid past the beveled surface 69 on the master valve spool. .When this flow is completely out off the working liquid from the pump is about to be admitted from the recess" 'to the recess 46 as shown in Fig. 7, at which timefthe pumped liquidunder pressure will cause the piston to againas'cend within the cylinder l5.

This description thus completes the action; of

. accumulator.

the control apparatus for a full cycle of the operation of the piston 25.

Gages I and I 0| may be placed at difierent parts of the system to determine the pressure.

Gage I00 is placed adjacent the discharge of the pump 34 in the line 42 which registers a positive pressure at all times. ,The gage IIII placed at 2 .the top of the cylinder I in line 13 must be capable of reading negative or sun-atmospheric pressures as well as pressures thereabove.

Referring now to the pneumatic pumping the structure is the same as the hydraulic mechanism with the exception of the'master valve 30 and the source of fluid pressure supply. The

master valve 30 of the pneumatic controlsystem ated mechanism to a pneumatically operated .mechanism. The control valves and the pump enisms the pilot valve spring 32 may be replaced mechanism shown in Fig. 10, it will be noted that w 7 is provided with a continuous land section III! which prevents communication between therecess 45 containing fluid under pressure and the recess 51 leading through line 58 to the discharge line 60. This continuous land section prevents the escape of energized fluid from the source of supply while, the piston 25 is moving downwardly. In the hydraulic system the fluid may circulate but in a pneumatic system the fluid energy must not be needlessly wasted.

This pumping mechanism is arranged to be operated from any suitable source of gas under pressure. This source of supply may be obtained from a high pressure gas well or a compressor station which produces a head pressure on either gas or air. The compressor pumping station 1 preferably provided with the type of apparatus by the differential piston I2| which is actuated by fluid under pressure eflective through the line I22 which is connected tothe line 51. The left end of the pilot valve 28-and the'right end of the differential piston I2I are subjected to the same fluid pressure when-the piston passes the selected upper control line 62 or at the end of its upward stroke, but the pilot valve 28 will move to the right because the area-of the left end 3 of the pilot valve is greater than that of the differential piston. The pressure in the cylinder I5 under the piston as it descends maintains the check valve '12 in its closed position and the pressure effective against the left end of the pilot valve maintains it to the right until the piston 25' passes below the selected lower control line -'II'I 'or 11, at which time the low pressure above the piston discharges the pressure from the left end of the pilot valve 28. The pressure eifectiveirom usually employed for such purposes, including an The fluid under pressure is conveyed to the control mechanismvthrough the conduit I I I to the pressure regulator I|2 whence it travels through the pipe 42 to the control mechanism. 1

The disposition of the pneumatic working fluid depends upon the character of fluid employed. If the source of supply is a high pressure gas it is discharged through the line 60 to the valve H3 where it may pass to the lower pressure line .I I4. This line may be a common discharge line from a plurality of similar pumping units. Again the exhaust gas may lie-returned through the line 5' to the compressor station for recompression. If a combustible gas is used it may be piped to an accumulator where it is finally discharged to a furnace engine or other similar use. The line H6 connected tothe valve H3 is arranged to discharge the pneumatic fluid to the atmosphere. p v a Shut-off valves I I1 and I III are provided in the lines 42 and 50, respectively, to permit the pumping unit to be disconnected from the fluid system.

The pressure relief valve 43 is'provided with a communication I I5 between the extreme end faces to equalize the pressure acting thereon. This structure is required when the exhaust fluid pressure is discharged into a fluid pressure line. The pressure acting on the right face of the valve the line 41 through the line I22 again forces the pilot valve to the left, which action again reverses the master valve and the piston ascends. in its pumping stroke. Thus the same pumping action is obtained through the pilot control valve by the use of the di'iferential piston I2I in'place of the spring 32.

Referring to Figs. 10 and 11, the'piston provided with a hollow tubular extension I23 arranged to pass up through thepacking I24 in the head I25. The packing may be compressed by the gland member I26. The piston extension I23 is longer than the cylinder I5 and protrudes above the head I25 when the piston is in its lowermost position. Theupper end of the extension is provided with a small bore for receiving the polish rod 25. A packing I21 and a gland member I28 are provided for sealing the polish rod as it passes through the piston extension; A polish rod clamp I29 is secured to the rod above the piston for locking it thereto. A casing, not shown, may be slid over the piston extension and is also effective on the left face of-the valve. The

communicating passageway H9 thus .nullifles the effectiveness of the pressure in the fluid discharge line 50 and the valve is actuated by the small differential piston 55 in the same manner described above.

In pneumatically operated pumping mechanism I a pop valve I20 may be provided in the upper endof thecylinder l5 in the'sameposition as the gauge I0l described above. This valve is purely fastened to the head I25 to keep the dirt and weather of! the piston surface.

; The p rposeof this piston extension is to permit the operator to raise ,or lower the pump plunger in the well and thus properly space it from the bottom thereof to obtain the most effective operationof the well pump. Again the well pump is made more readily accessible with the polish rod extending above the apparatus.

In Fig. 12 a battery of fluid operated pumping ,mechanisms are shown connected to a common source of fluid pressure supply as indicated by the line no and the return or exhaust line m. 'f

These pumping units may be operated pneumatically or hydraulically from a common source of supply. The valves Ill and H8 together with the unions permit the removal of any one unit from the system without disturbing the operation of the other units.

In'Flg. 13 the fluid pumping mechanism a supported in the horizontal position by the base casting I32. A similar casting may beused for supporting the other end of" the cylinder 15. In

this instance the polish rod 25- is replaced by a pull rod I22 which extends to the depending arms of the pump Jacks I34. Theloadon the polish has been converted from a hydraulically operrods wh ch a e sup o d m th ute n r t y lkiee b ms he um e k is balanced to provide theproper gravity, return Iorce for movingp tlie piston}! or the'punipin'g mechanism to theleft, ,Whichis the samefas returning. it to the bottom or the cylinder in the, other -views. The, pistonin each instance is thus biased by the gravitational forces'oi the pumping mechanism and load Thusit is obvious that this fluid motor may be employed in cotton tampers, baling'presses, stoker rams,

or any other type of mechanism requiring a continuous reciprocating cycle of operation as long as some means is provided to bias or reverse the movementof the .pistonon the non-load stroke. 7 v

Iclaim: 1. In a fluid operated pumping'mechanism, the

combination of a cylinder, a piston working in the cylinder and biased to move toward one end of the latter, a master valve arranged when in one position to admit-fluid under pressureto one end of the cylinder to move the piston toward the other end and when in another position to relieve the iiuid pressure from the cylinder to permit the piston to jreturn,a pilot valve arranged to control the,operation of the master valve, two sets of control lines, one set entering the cylinder adjacent one end and the other adjacent the other end for regulating the stroke ingline connecting the master valve to the first mentioned end of the cylinder, a fluid pressureactuated pilot valve arranged to control the oper'ationoi the master valve, a manually operated, ',valve for selecting the limit of the stroke of the piston at the second mentioned end of the cylinder, an idling control line connecting the operating, line with said selector valve, two control lines forming independent connections between said selector valve and longitudinally spaced ports adjacent the second mentioned end of the cylinder, a second manually operated valve for selectingv the limit of the stroke of the piston 'at'the first mentioned end of the cylinder, two

control lines forming independent connections v between said second selector valve and longitudinally spaced ports adjacent the first mentioned end i of the cylinder, a passageway connecting each of said selector valves with a common connection to the pilot valve, a check valve admitting flowirom the first selector valve to the pilot 'ond'selector valve to actuate the pilot valve in the of thepiston, check valve mechanism, and unitary means for selectively connecting one control line through said check valve mechanism from each set with the pilot valve for operating the same, the pressure of the ,fluid being efiective through a selected control line at one end to ac- K piston toward the other end of the cylinder and when in another position to relieve the fluid pressure and permit thepiston to return, an operatand the position of either end other direction.

3.In a hydraulic pumping mechanism the combination of a cylinder, a piston working in 1 said cylinder and biased to move toward one end of the latter, fluid pressure-operated valvular means for admitting fluid under pressure to and discharging it from the said end, of the cylinder to be eii'ective on one side of the piston,'two sets of control lines connected with said cylinder, the connections of the individual lines of each set being in spaced relation, two passages connected to said valvular means and having oppositely working check valves therein, each set of control lines having one of said passages operatively associated therewith, and means for selectively connecting one of the control lines of a set with the corresponding passage for varying the length of the piston stroke in the cylinder.

' LOUIS A. RINGMAN.