US2244428A - Oil well pump and counterbalance - Google Patents

Description

June 3, 1941, c. M. OLEARY OIL WELL PUMP AND COUNTERBALANCE 2 Sheets-Sheel'l 1 Filed March 18, 1958 .Fume 3, 1941. c. M. oLl-:ARY

OIL WELL PUMP AND COUNTERBALANCE 2 sheets-Sheet 2 Filed March 18, 1938 /M/fA/o/e @www M @MARY ma MM Qullllll.IIIIIHJJiIIIl11|IJ1II Patented June 3, 1941 UNITED STATES PATENT OFFICE OIL WELL PUMP AND COUNTEBBALANCE Charles M. OLeary, Los Angeles, Calif. Application March 18, 1938, Serial No. 196,751

(ci. 'i4-589) 24 Claims.

This invention relates to pumping devices, and particularly pertains to an oil well pump and counterbalance.

'I'he present invention is particularly concerned with well pumping rigs which embody the use of a walking beam mounted upon a stationary support, and which beam is operatively connected to a well pumping mechanism suspended Within a well, the beam being further provided with power means for oscillating the beam and for reciprocatin'g the well pumping mechanism. In devices of such character the condition prevails that on the down stroke the weight of the pump rods acts to assist the downward oscillating swing of the walking beam while on the up stroke the weight of the pump rods and the weight of the column of liquid being pumped is imposed upon the walking beam, thus creating unequal torque and load conditions upon the power unit during each cycle of its operation. It is the principal object of the present invention therefor to compensate and counterbalance the pumping mechanism during its cycle of operation whereby a substantially uniform torque load will be imposed upon the power unit.

The present invention contemplates the provision of the usual walking beam, a power unit for oscillating the same, a connecting means upon the free end of the walking beam for reciprocating a pumping mechanism, and a uid countelrbalance structure interposed between the free end of the walking beam and a rigid base, said counterbalance structure acting to cushion and compensate load conditions of the walking beam during its cycle of operation.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a view in side elevation showing an application of the present invention.

Fig. 2 is a View in central vertical section through the fluid cushioning device showing the details of its construction.

Fig. 3 is a top view of the compression tank.

Referring more particularly to the drawings I indicates a Samson post upon which a walking beam is mounted. A pivot pin I2 attaches the walking vbeam to the Samson post and permits free oscillating movement of the walking beam. At one end of the walking beam is a horse head I3 to receive the reins I4 of a polish rod l5. It will be understood that the polish'rod extends downwardly into a well casing I6 and operates the plunger II of a pump. At a point in the length of the walking beam a pivot pin I8V is mounted to receive the end of a pitman rod I9.

The pitman rod is connected by a wrist pin 20 with a crank 2| which is mounted upon a shaft 22 driven by a pulley 23. It is understood that the pulley receives its power from a. suitable source of power supply not shown, and that if desired other forms of driving mechanism may be used. The drawings in the present instance merely show a simple form of power unit and it is to be understood that while the Walking beam is here shown as being of the simple lever type, power might be applied to the beam at other points, such for example as at a point between the horse head and the Samson post.

Disposed at a point between the horse head and the Samson post is a pivot 24 to which the upper .end of a piston rod 25 is connected. This rod extends downwardly to operatively connect the cushioning unit 26 with the walking beam. By reference to Fig. 2 it will be seen that the rod 25 extends downwardly through a guide spider 26. This spider as shown in Fig. 3 is formed with a. plurality of guide arms 2l between which an air circulating space 28 occurs. is mounted over the upper end of a balancing cylinder 29 and guides the piston rod 25 as it reciprocates Within the cylinder 29 and moves its piston 30. The cylinder 29 is mounted within a tank 3|. The head 32 of the tank receives a flanged shoulder 33 of the cylinder 29 through whichcap screws 34 pass and by which the cylinder 29 is held in position to seal the tank 3| and to form a compression space 35 therein and around the cylinder 29. The lower end of the cylinder 29 is provided with a head 36 having an opening therethrough to which is attached a pipe 3l. The pipe 3l extends downwardly and communicates with a main control valve 38, the opposite side of which valve is provided with a pipe 39 connected with a T 40. The T 40 connects with pipes 4| which in turn establish communication with the tank 3|y through its bottom head 42. The valve 38 therefor can be used to regulate or interrupt flow of uid from the cylinder 29 hereinafter designated as the balancing cylinder and for purposes to be herein'after set forth. A draw-oir pipe 43 extends through the Wall of the tank 3| and estabishes communication with the lower end of the balancing cylinder. This pipe is connected with a four-way coupling 44. 'Ihe lower leg of this coupling is connected with a bleeder valve 45. The upper leg of the coupling connects with a pipe 46 which carries a. check valve 41 connected in turn through a pipe 48 with the tank 3 I. The remaining leg of the member 44 is provided with a check valve 49. The

The spider check valve 4l operates to permit a flow of fluid from pipes 43 and 46 to pipe 48 and into the tank.

The check valve 49 is designed to permit inow of air under suction action of the piston 30 and a subsequent introduction of said air into the tank 3| on the compression stroke of piston 30 in the manner and for the purpose to be hereinafter set forth.

Mounted in the upper end of the balancing cylinder 29 is an oil overflow drain pipe 50 which leads to an oil reservoir tank I. A flexible section 52 is provided in the length of the pipe 50 in order to accommodate movement of the tank 3| as will be hereinafter described. At a point below the draw-off pipe 50 and in the length of the tank 3| is a pipe 53 which connects with a T 54. One side of the T is fitted with a pop valve 55 which is set to release at a desired pressure by manipulation of a regulating screw 56. A conduit 51 leads from the valve to the oil reservoir 5| and a flexible section 58 accommodates movement of the tank 3|. The other leg of the T 54 connects with a check valve 59 through which fluid may flow to the T from a make-up pump 60. 'I'his pump comprises a cylinder 6I within which a plunger 62 reciprocates. The plunger 62 is pivoted to a lug 63 by a pivot pin 64. 'I'he lug 63 is mounted on the side of the tank 3|. The check valve 59 connects with the head of the cylinder 6| by a pipe 65. Diametrically opposite the pipe 65 is a pipe 66 carrying a check valve 61. The check valve 61 communicates with a conduit 68 leading to the bottom of the oil reservoir tank 5|. The head end of the cylinder 6| is pivoted by a pin 69 to a thrust bar l0. The opposite end of this thrust bar is pivoted at 1|- to a bracket 12 mounted upon the frame structure of the Samson post I0. The conduit 68 conveys oil to the make-up pump 60 on its suction stroke. This oil may pass through the check valve 61 to the cylinder but the check valve will prevent a return flow of oil through the pipe 68. The entire structure generally designated by the numeral 26 as a cushioning unit is provided with trunnions 14 which extend horizontally from opposite sides of the tank 3| near the lower end thereof and are carried in bearings mounted upon a supporting bracket 16.

In operation of the present invention the entire structure is assembled as shown in the drawings, it being understood as previously stated that the assembly of parts is here disclosed by way of example. In the structure as here assembled the main valve 38 is initially open to' insure that a suiiicient volume of incompressible liquid, such for example as oil, occurs within the compression space 'Il of the balancing cylinder 29.

The fundamental operation of the present device is directly concerned with the relative proportions of incompressible fluid and compressible fluid within the pumping system, and the manner in which these fluids are utilized during the pumping operation. It will be understood that in deep well pumps the problem of pumping is concerned with the condition created by the weight of the sucker rods and the load of fluid being lifted on the upstroke and the weight of the sucker rods and the action of fluid displacement in the Well on the downstroke. For example, assuming that the total weight of the sucker rods to be reciprocated is 1000 pounds, and that to this is added an assumed fluid head or load of 1000 pounds to be lifted by the use of a pump structure having a piston of 2% in Cil diameter or 3.97 square inches of exposed area against a 585 foot head or depth oi pump at 0.43 pound per square inch static head pressure per foot of depth. This would result in a formula as follows:

585 0.43 3.97=1000# fluid load to be lifted on each stroke of the piston in addition to the 1000# rod weight, making a total load of 2000# to be lifted.

In order to properly equalize or countcrbalance this ty-pe of weight, that is to say 1000# and 2000# disposed on the pumping mechanism alternately during each of revolution, it will be necessary first to bring the static weight of the rods into equilibrium by the expedient of applying suflicient pressure of air beneath piston 30 to lift a load of 1000# at the polish rod l5. This is the first principle of operation oi the present device and if the mechanism was placed in operation under these conditions of balance. the operation would be as follows:

During the upstroke of the beam Il and the attached parts,the load to be lifted would be 1000# of rod plus 1000# of fluid, and if the system had been adjusted so that the pressure of air acting beneath the piston 30 to lift 1000# of this load, it would be necessary for the prime mover transmitting power through crank 2l and the rod I9 to lift the other 1000# of load. It will be understood that at the end of the upstroke the fluid load will be assumed by the standing valve and then the downstroke would be aided by 1000# of rod load. This rod load will at the same time be resisted by the air in the balancing device acting beneath the piston 30. It is obvious that under these conditions the prime mover would be called upon to lift 1000# during the upstroke and would require no vpower input during the downstroke. This is not an ideal operating condition as compared to an adjustment and balance of the iiuid system in which the air balance is used for the purpose of lifting all of the rod weight at all times, together with onehalf of the Weight of the fluid which it is required to be lifted. The formula controlling this operation is as follows:

B=plus g in which B=the lifting force in pounds at` the polish rod of the air balance device.

R=the weight of the rods in the well.

F=the fluid load to be lifted, that is the rea of the pump bore times the weight of the liquid times the depth of the Well in feet.

If the apparatus is operated in this manner it Will be evident that the 2000# of weight to be lifted would be aided by 1500# vof lifting force applied by the balancing device. This would mean 500# of lifting force to be supplied by the prime mover on the upstroke. Then on the downstroke there will be 1500# of resistance supplied by the balancing device aided by 1000# of rod weight which would leave 500# of power to be supplied by the prime mover. It will be evident that in this way the prime mover will be required to supply 500# of power on the upstroke and 500# of power on the downstroke, which would mean that the load on the prime mover is reduced fifty percent over that present when the balancing device balances the weight of the rods only, thereby reducing the torque and stress in the complete mechanism proportionately.

When desired, for purposes hereinafter set and into tank 3|.

forth, the check valve 49 may be utilized to permit a flow lof air from the atmosphere to intermittently enter cylinder 29 below piston 30 by way of fitting 44 and pipe 43. This phase of operation is necessary at intervals for the purpose of establishing a perdetermined pressure of air in the tank 3|, and may be accomplished by closing valve 38, thereby causing the non-compressible liquid contained in cylinder 29 below piston 30 to be forced into tank 3l upon the first downward stroke of piston 30, by way of pipes 43 and 46 and through one way check 41 Thereafter, however, upon further reciprocation of the piston 30 within cylinder 29 air will be caused to be drawn into cylinder 29 by piston 30 during its up-stroke by entering through check valve 49, at atmospheric pressure, and into cylinder 29 by way of fltting 44 and pipe 43, then to be displaced by piston 30, upon its followingdownward stroke, into tank 3| by way of pipe 43, tting 44, pipe 46, and through check 41 into tank 3|. Thereby utilizing cylinder 29 and piston 30, together with their associated parts, as a means for developing a predetermined pressure of air in tank 3| It is intended that a predetermined set pressure shall be maintained within the tank 3| This is created and controlled by the relative volumes of air and oil within the tank 3| at all times. In the event that oil leaks around the piston 30 so that the set volume of oil within the compression space 11 of the piston and the compression space 35 of the tank is depleted by leaking around the piston this oil will overflow into the pipe 5U and will then drain into the oil supply tank 5|. The volume of oil within the compression space 35 of the tank 3| will then be made up by oil which is drawn from the bottom of the tank 5| to the conduit 68 and then injected into the compression space 35 of the tank 3| by action of the make-up pump 60. This pump is incidentally operated as the walking beam oscillates and the cushioning device 26 oscillates on its trunnions 14. In actual operation the cushioning device 26 has an oscillating swing of approximately and this swinging movement will cause the plunger 62 to reciprocate within the cylinder 6|, alternately drawing in oil through the conduit 68 on the out stroke and forcing the oil through the conduit 65 and the pipe 53 on the in stroke. This oil will thus be forced into the tank 3| and will make up the quantity of oil within the tank until a predetermined volume and pressure has been reestablished. When this takes place as determined by the adjustment of the set screw 56 on the pop valve 55 the pumped oil will be diverted through the pop valve 55 and the draw-off pipe 51 to the storage tank 5|. This return flow of oi1 will continue until the fluid pressure Within the chamber 35 of the tank 3l is lowered vand resistance to fluid flow has become such as to cause the pop valve 55 to close and the oil to be directed into the tank 3|.

It is to be understood that while the pump 6U is here shown and described as being used for pumping oil that in some instances it might be desirable to dispense with the liquid in the system and maintain a cushioning and counterbalancing action by air alone in which case it is evident that the pump 60'may be used to create a desired air pressure as the balancing and cushioning structure oscillates and incident to its operation. This acts to maintain the air in the tank 3| at a pre-determined pressure.

It may be desirable to return the excess liquid from the tank 3| to the supply tank 5|. In such cases a return pipe is provided having a cutoff valve 86. It will thus be seen that the cushioning and counterbalancing structure here disclosed provides simple and ellective means whereby a compressible fluid and an incompressible fluid may be maintained in a given proportion, and at a constant pre-determined pressure within a closed circuit of travel, thus insuring an automatic fluid cushioning and counterbalancing action cooperating with a power pump mechanism.

While I have shown the preferred form of my invention, as now known to me, it will be understood that various changes might be made in the combination, construction, and arrangement of parts, by those skilled in the art, without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A counterbalance device adapted to be interposed between the base and the walking beam of a pumping mechanism and to have free pivotal movement in vthe plane of oscillation of the walking beam, said device comprising a cushioning tank within which a compressible and an incompressible fluid are entrapped, a balancing cylinder having a working chamber in constant communication with the tank in the zone of the tank containing incompressible fluid, a piston within said balancing cylinder connected with the walking beam, means incident to the operation of the piston in said working chamber of the cylinder for forcing compressible fluid into the tank and means controlled by pressure in the cushioning tank for feeding incompressible fluid thereto.

2. In a power driven walking beam pump. cushioning and counterbalance means including a balancing cylinder, a piston therein, a piston rod attached thereto and pivoted to the walking beam whereby oscillation of the walking beam will produce reciprocation of the piston, a cushioning tank, the lower end of which is in free communication with the lower end of the balancing cylinder, said lower portion of the cushioning tank and the portion of the balancing cylinder below its piston being filled with an incompressible fluid. the upper portion of the cushioning tank containing a compressible fluid, and

. separate means in communication with the lower end of the balancing cylinder and the cushioning tank whereby compressible fluid may be automatically pumped into the tank when the fluid pressure in the tank drops below a predetermined value.

3. In a. power driven walking beam pump, cushioning and counterbalance means including a balancing cylinder, a piston therein, a piston rod attached thereto and pivoted to the walking beam whereby oscillation of the walking beam will produce reciprocation of the piston. a cushioning tank, the lower end of which is in free communication with the lower end of the balancing cylinder, said lower portion of the cushioning tank4 and the portion of the balancing cylinder below its piston being filled with an incompressible fluid, the upper portion of the cushioning tank containing a compressible fluid, separate manually controlled means in communication with the lower end of the balancing cylinder and the lower end of the cushioning tank whereby air may be pumped into the tank when the .-at its upper end, a closed tank with which said cylinder communicates at its lower end, a piston within said cylinder, the compression space of which is filled with incompressible fluid, a conduit through which said fluid is displaced from the cylinder into the tank in a free flow and having a cut off valve, and a conduit carrying a check valve through which fluid is displaced at will from the cylinder into the tank in one direction only when said cut off valve in the first conduit is closed, said cylinder having an air inlet provided with an air intake valve normally held closed while said ilrst conduit is open,

5. In a power driven walking beam pump, cushioning and counterbalance means comprising a balancing cylinder open to the atmosphere at its upper end, a closed tank with which said cylinder communicates at its lower end, a piston within said cylinder, the compression space of which is filled with incompressible fluid, a conduit through which said fluid is displaced from the cylinder into the tank in a free flow, a conl duit carrying a check valve through which fluid is displaced at will from the cylinder into the tank in one direction only, and means for interrupting said free ilow of fluid, said cylinder having an air inlet provided with an air intake valve normally held closed during free flow of liquid.

6. In a power driven walking beam pump, cushioning and counterbalance means comprising a balancing cylinder open to the atmosphere at its upper end, a closed tank with which said cylinder communicates at its lower end, a piston within said cylinder, the compression space of which is filled with incompressible fluid, a conduit through which said fluid is displaced from the cylinder into the tank in a free ilow, and a conduit carrying a check valve through which fluid is displaced at will from the cylinder into the tank in one direction only, and means associated with said last named conduit whereby air will be drawn at will into said conduit and forced into said tank.

7. In a power driven walking beam pump, cushioning and counterbalance means comprising a balancing cylinder open to the atmosphere at its upper end, a closed tank with which said cylinder communicates at its lower end, a piston within said cylinder, the compression space of which is filled with incompressible fluid, a conduit through which said fluid is displaced from the cylinder into the tank in a free flow, and a conduit carrying a check valve through which fluid is displaced at will from the cylinder into the tank in one direction only, and means automatically operating incident to the action oi.' said balancing cylinder -whereby additional quantities of incompressible fluid may be introduced into the tank when fluid pressure falls below a predetermined minimum and until said minimum has been re-established.

8. In a power driven well pump of the type including a walking beam at the free end of which well pump rods are suspended, a fluid cushioning and counterbalancing device interposed between said walking beam and a fixed base, and

comprising a .tank pivoted to the base at its lower end, a balancing cylinder within the tank and forming a seal with the upper end of the tank while being open to the atmosphere, a piston rod attached to the walking beam and reciprocating within said balancing cylinder, a piston thereon, a fluid conduit from the lower end o! the balancing cylinder to the tank and within which an incompressible fluid is placed, said duid being displaced from the balancing cylinder into the tank upon the downward reciprocation of the piston, .the quantity of incompressible fluid in the tank being sufficient to only partially illl the tank and allow a compressible fluid to be entrapped in the tank thereabove, and a valved conduit establishing communication between the lower end of the balancing cylinder and the tank at a point below the level of the accumulated incompressible fluid therein, for the flow of said fluid from the cylinder into the tank only.

9. In a power driven well pump of the type including a walking beam at the free end of which well pump rods are suspended, a fluid cushioning and counterbalancing device interposed between said walking beam and a fixed base, and comprising a tank pivoted to the base at its lower end, a balancing cylinder within the tank and forming a seal with the upper end of the tank while being open to the atmosphere, a piston rod attached to the walking beam and reciprocating within said balancing cylinder, a piston thereon, a fluid conduit from the lower end of the balancing cylinder to the tank and within which an incompressible fluid is placed, said fluid being displaced from the balancing cylinder into the tank upon the downward reciprocation of the piston and into the balancing cylinder upon upward movement of piston, the quantity of incompressible iluid in the tank being suilicient to only partially fill the tank and allow a compressible fluid to be entrapped in the tank thereabove, a valved conduit establishing communication between` the lower end of the balancing cylinder and the tank for the flow of said fluid from the cylinder into the tank only, and manually controlled means for causing the piston to draw air into the cylinder through said last named conduit automatically and force it into the tank to increase the fluid pressure therein.

l0. In a power driven well pump of the type including a walking beam at the free end of which well pump rods are suspended,` a fluid cushioning and counterbalancing device interposed between said walking beam and a fixed base, and comprising a tank pivoted to the base at its lower end, a balancing cylinder within the tank and forming -a seal with the upper end of the tank while being open to the atmosphere, a piston rod attached to the walking beam and reciprocating with said balancing cylinder, a piston thereon, a fluid conduit from the lower end of the balancing cylinder to the tank and within which an incompressible fluid is placed, saidiluid being displaced from the balancing cylinder into the tank upon' the downward reciprocation of the piston and displacing the piston on the upward movement of same, the quantity of incompressible fluid in Ithe tank being sufficient to only partially lill the tank and allow a compressible fluid to be entrapped in the tank thereabove, a valved conduit establishing communication between the lower end of the balancing cylinder and the tank and through which fluid ows from the cylinder into the tank only, and means for causing the piston to draw air into the cylinder through said last named conduit automatically and force it into .the tank to increase the fluid pressure therein, including manua.ly operated means for cutting oil the direct ow of uid through said rst named conduit from the balancing cylinder to the tank.

11. In a power driven well pump of the type including a walking beam at the free end of which well pump rods are suspended, a fluid cushioning and counterbalancing device interposed between said walking beam and a xed base, and comprising a, tank pivoted to the base at its lower end, a balancing cylinder within the tank and forming a seal with the upper end of the tank while being open to the atmosphere, a piston rod attached to the walking beam and reciprocating within said balancing cylinder, a piston thereon, a uid conduit from the lower end of the balancing cylinder to the tank and within which an incompressible uid is placed, said iuid being displaced from the balancing cylinder into the tank upon the downward reciprocation of the piston, `and displacing said piston upon upward movement of same, the quantity of incompressible uid in the tank being sufficient y to only partially ll the tank and allow a cornpressible uid to be entrapped inthe tank thereabove, a valved conduit establishing communication between the lower end of the 4balancing cylinder and the tank through which uid may flow from the cylinder into the tank only, manually controlled means for causing the piston to draw air into the cylinder through said last named conduit automatically and force it into the tank to increase the iiuid pressure therein, a pump actuated continuously incident to the oscillation of the walking beam to deliver incompressible uid 1:0 said tank when the uid pressure within the tank is lowered to a predetermined minimum, and means automatically diverting said pumped iluid from delivery to the tank when said predetermined minimum pressure has been restored.

12. In a power driven well pump of the type including a walking beam at the free end of which well pump rods are suspended, a` iluid cushioning and counterbalancing device interposed between said walking beam and a xed base, and comprising a tank pivoted to the base at its lower end, a balancing cylinder within the tank and forming a seal with the upper end of the tank while being open to the atmosphere, a piston rod attached to the walking beam and reciprocating within said balancing cylinder, a piston attached to'said piston rod, a iluid conduit from the lower end of the balancing cylinder to the tank and within which an incompressible fluid is placed, said fluid being displaced from the balancing cylinder into the tank upon the downward reciprocation of the piston and said iluid displacing said piston upon upward movement of same, the quantity of incompressible uid in the tank being sufcient to only partially ll the tank and allow a" compressible fluid to be entrapped in the tank thereabove, a valved conduit establishing communication between the lower end of the balancing cylinder and the tank, and through which iiuid ows from the cylinder into the tank only, manually controlled operated means acting when the pressure of the fluids within the tank have reached a predetermined minimum to cause the piston to draw air into the cylinder through said last named conduit automatically and force it into the tank to increase the fluid pressure therein, a pump actuated concylinder for supplying tinuously and automatically incident to the oscillation of the walking beam to deliver incompressible uid to said tank when the uid pressure within the tank is lowered to a predetermined minimum, means automatically diverting said pumped fiuid from delivery to the tank when said predetermined minimum pressure has been restored, and a manually operated bleeder valve for permitting the escape of iluid from the balance cylinder when desired.

13. A counterbalancing device for use with the walking beam of a.we1l pump mechanism, said device comprising the combination of a cylinder, piston, and piston rod constituting an Aair cushion in connection with said beam, an air cushioning tank having connection with said cylinder for supplying pressure thereto constantly during operation, the compression end of said cylinder and the bottom of the tank being lled with anv incompressible uid, a cut-olf valve disposed in the connection between lthe tank and the cylinder, and means acting automatically incidentto the operation of the piston while said valve is closed to draw air into the cylinder and to force it under pressure into the tank.

14. A counterbalancing device for use with the walking beam of a well pump mechanism, said device comprising the combination of a cylinder. piston, and piston rod constituting an air cushion in connection with said beam, an air cushioning tank having an incompressible fluid trapping air therein, and having connection with said incompressible fluid thereto constantly during operation, a cut-oil valve disposed in the connection between the tank and the cylinder, and means acting automatically incident to the operation of the piston While said valve is closed to draw air into the cylinder and to force it under pressure into the tank.

15. A counterbalancing device for use with .the walking beam of -a well pump mechanism, said device comprising a piston connected to the walking beam, a cylinder within which it operates, said cylinder being mounted to oscillate as the walking beam moves, a cushioning tank having an incompressible fluid entrapping air therein, and in communication with the compression end of said cylinder for the supply of incompressible iluid to the cylinder, a cut-oi valve in said communicating line between the tank and-cylinder, and a bleeder valve in communication with the cylinder and the tank whereby the quantity of incompressible iuid within the cylinder and the tank may be regudated when the cut-olf valve is closed.

16. A counterbalancing device for use with the walking beam of a well pump mechanism, said device compriisng a piston connected to the walking beam, a cylinder within which it operates, said cylinder being mounted to oscillate as the walking beam moves, a cushioning tank in communication with the compression end of said cylinder, a cut-off valve in said communicating line, the compression end of the cylinder and the lower communicating portion of the tank being lled with an incompressible iluid, a communicating conduit `between the compression end of the cylinder and the tank, and a bleeder valve connected therewith whereby the quantityof incompressible fluid within the cylinder may be regulated when the cut-ofi' valve is closed and the bleeder valve is opened.

17. A counterbalancing device for use with the walking beam of a well pump mechanism, said incompressible iiuid, a communicating conduit between the compression end of the cylinder and the tank, and a bleeder valve connected therewith whereby the quantity oi incompressible iiuid within the cylinder may be regulated when the cut-oi! valve is closed and the bleeder valve is opened and an air inlet check valve communi. cating with said conduitv and through which air may be drawn into the cylinder and forced into the tank when the bleeder valve is closed and the cut-oi valve is closed.

18. In a counterbalance, an upright, closed tank, a cylinder therein opening at its top through the top of the tank, the lower portion of said tank and the cylinder having therein an incompressible liquid, forming in the upper portion of the tank a space for a compressible fluid, a piston in said cylinder on the liquid, having a piston rod projecting through the open top of the cylinder, a connection extending from the lower portion of the cylinder into the lower portion of the tank and normally providing for the transfer of liquid freely from the former to the latter and vice versa, a cut oi valve in said connection, a second connection between the lower portion of the cylinder and the lower portion of the tank having therein a check valve limiting movement of iiuid into the tank only, and a fluid inlet having a check valve and bleeder having a cut off valve, both said fluid inlet and bleeder communicating with the lower portion of the cylinder through a.` portion of said second connection.

19. In a pumping apparatus of the type including a power actuated vertically oscillating walking beam, cushioning and counterbalancing means comprising a tank pivoted at its lower end to a xed base, a balancing cylinder associated with said tank and movable therewith, a piston within the balancing cylinder, a piston rod carried by the piston and extending outwardly of the upper end of the cylinder and pivotally connected to the walking beam, a conduit establishing free communication between the lower end of the balancing cylinder and the lower end of the tank, a cut ofl valve in said conduit, the space within the balancing cylinder below the piston and the lower portion of the tank being lled with an incompressible iluid, the upper space within the tank containing the cornpressible fluid, a second conduit connecting the compression end of the balancing cylinder and the tank, and a check valve at a point in said second conduit for permitting iiow of iluid from the cylinder to the tank only.

20. In a pumping apparatus of the type including a power actuated vertically oscillating walking beam, cushioning and counterbalance means comprising a tank pivoted at its lower end to a fixed base, a balancing cylinder associated with said tank and movable therewith, a piston within the balancing cylinder, a piston rod carried by the piston and extending outwardly of the upper end of the cylinder and pivotally connected to thewalking beam, a conduit establishing free communication between the lower end of the balancing cylinder and the lower end of the tank, a cut of! valve in said conduit, the space within the balancing cylinder below the piston and the lower portion of the tank being iilled with an incompressible fluid, the upper space within the tank containing the compressible fluid, a'second conduit connecting the compression end of the balancing cylinder and the tank, a check valve at a point in said second conduit for permitting ow of iluid from the cylinder to the tank only, and a bleeder valve connecting with said second conduit through which uid from the balancing cylinder may be drained.

21. In a pumping apparatus of the type including a power actuated vertically oscillating walking beam, cushioning and counterbalance means comprising a tank pivoted at its lower end to a xed base, a balancing cylinder associated with said tank and movable therewith, a. piston within the balancing cylinder, a piston rod carried by the piston and extending outwardly of the'upper end oi the cylinder and pivotally connected to the walking beam, a conduit establishingiree communication between the lower end of the balancing cylinder and the lower end of the tank, a cut oi valve in said conduit, the space within the balancing cylinder below the piston and the lower portion of the tank being filled with an incompressible fluid, the upper space within the tank containing the compressible uid, a second conduit connecting the compression end of the balancing cylinder and the tank, a check valve at a point in said second conduit for permitting flow of iiuid from the cylinder to the tank only, and an inlet check valve to the second conduit for permitting atmospheric air to be drawn into the balancing cylinder.

22. In a pumping apparatus of the type including a power actuated vertically oscillating walking beam. cushioning and counterbalance means comprising a tank pivoted at its lower end to a fixed base, a balancing cylinder associated with said tank and movable therewith, a piston within the balancing cylinder, a piston rod carried by the piston and extending outwardly of the upper end of the cylinder and pivotally connected to the walking beam, a conduit establishing free communication betwee'n the lower end of the balancing cylinder and the lower end of the tank, the space within the balancing cylinder below the piston and the lower portion of the tank `being iilled with an incompressible iluid, the upper space within the tank containing the compressible iiuid, a second conduit connecting the compression end' of the balancing cylinder and the tank, a check valve at a point in said second conduit for permitting ilow of fluid from the cylinder to the tank only, an inlet check valve to the second conduit for permitting atmospheric air to be drawn into the balancing cylinder and a valve in said rst conduit through which conduit normal free circulation of iluid from the bottom of the balancing cylinder to the tank is established and which valve may be closed whereby suction ofthe balancing cylinder will act to draw air through the intake check valve4 of the second conduit and will force said air into the tank on the compression stroke of the piston within the balancing cylinder.

23. In a pumping apparatus of the type comprising an oscillating power actuated walking beam, cushioning and counterbalancing means comprising a cushioning cylinder pivoted at its lower end, a balancing cylinder rigidly associated with the cushioning cylinder, a piston within the balancing cylinder, a piston rod extending from said piston and pivotally connected to the walking beam, the portion of the balancing cylinderV below the piston being filled with an incompressible iiuid and a portion of the cushioning cylinder being lled with said incompressible fluid, a conduit establishing constant communication between the lower end of the balancing cylinder and the lower end of the cushioning cylinder whereby said incompressible iiuid may have unrestricted low between the two cylinders, the upper end of the cushion cylinder being filled with a compressible uid, a second conduit establishing communication between the compression end of the balancing cylinder and the cushioning cylinder at a level below the level of the incompressible uid in the cushioning cylinder and having therein a check valve opening toward the cushioning cylinder, a valve in the firstnamed conduit between the balancing cylinder and the cushioning cylinder which when closed will cause the displaced fluid in the balancing cylinder to be forced directly into the cushioning cylinder through said second conduit, and an air intake check valve in communication with the second named conduit whereby on the suction stroke of the piston within the balancing cylinder air will be drawn into the uid system and on the subsequent compression stroke of the balancing cylinder will be forced into the cushioning cylinder.

24. In a pumping apparatus of the type comprising an oscillating power actuated walking beam, cushioning and counterbalancing means comprising a cushioning cylinder pivoted at its lower end, a balancing cylinder rigidly associated with the cushioning cylinder, a piston within the balancing cylinder, a piston rod extending from said piston and pivotally connected to the walking beam, the portion of the balancing cylinder below the piston being fllled with an incompressible fluid and a portion of the cushioning cylinder being filled with said incompressible fluid, a conduit establishing constant communication between the lower end of the balancing cylinder and the lower end of the cushioning cylinder whereby said incompressible fluid may have unrestricted now between the two cylinders, the upper end of the cushioning cylinder being lled with a compressible uid, a second conduit establishing communication between the compression end of the balancing cylinder and the cushioning cylinder at a level below the level of the incompressible fluid in the cushioning cylinder, and having a check valve therein opening toward the cushioning cylinder, a valve in the first named conduit between the balancing cylinder and the cushioning cylinder which when closed will cause the displaced fluid in the balancing cylinder to be forced directly into the cushioning cylinder through said second conduit, an air intake check valve in communication with the second named conduit whereby on the suction stroke of the piston Within the balancing cylinder air willbe drawn into the balancing cylinder and on the subsequent compression stroke of the balancing cylinder will be forced into the cushioning cylinder, and a bleeder valve in the line of said second named conduit, said bleeder valve when opened relieving the fluid pressure within the balancing cylinder and permitting the fluid to be drawn from the balancing cylinder whereby the spaced position of the piston Within the balancing cylinder may be set.

CHARLES M. OLEARY.

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