US2184437A - Counterbalancing system for oil wells - Google Patents

Description

Filed July 2, 19 38 2 Sheets-Sheet 1 //v v/v TOR 6y WAL 76/? A. 6A XE HARR/s, K/ECH, Fos n: R a HARE/5 FOR TH FIRM Arromvzms.

Dec. 26, 1939. v w. E. SAXE 2,184.43?

COUNTERBALANCING SYSTEM FOR OIL WELLS Filed July 2, 1938 2 Sheets-Sheet 2 gale M FOR THL' FIRM Pirated Dec. 26, 1939 PATENTS OFFICE COUNTERBALANCING SYSTEM FOR OIL WELLS Walter E. Saxe, Alhambra, Calif. Application July 2, 1938, Serial No. 217,113

20 Claims.

invention relates to a counterbalancing system for oil wells and is a continuation-in-part of my copending application, Serial No. 103,169,

filed September 29, 1936, entitled Method and apparatus ior counterbalancing oil well pumping apparatus. a Y

In oil well pumping apparatus, the reciprocating mechanism, including the pump plunger and connecting parts, may be counterbalanced by employing a confined body of gas, compressing the gas to store energy from the apparatus durvide an apparatus whereby, when the prime ing the, downstroke of the pump plunger and expanding the gas to return energy to the apparatus during the plungers upstroke, thereby equalizing the loadon the prime mover during the two plunger strokes. When the prime mover is not in operation, the pump plunger and the reciprocating mechanism in such an arrangement may be moved upwardly by adding compressed gas to the counterbalancing system and may be moved downwardly by releasing compressed gas from the system. The latter of these steps is objectionable because it dissipates the energy stored by the compression of gas in the system and the former of these steps is objectionable because such a large volume of compressed gas must be added to the system to overcome inertia of the reciprocating parts before the upward movement commences, that, thereafter the compressed gas continues to expand and generally moves the reciprocating parts upward beyond the desired mark, accurate controlbeing impossible.

It is one of the objects of my invention to provide a counterbalancing system whereby, as a result of travel of liquid in the counterbalancing system, the load upon the prime mover during the upstroke of the pumpplunger is made substantially equal to the load thereon during the plungersdownstroke.

It is a further object of my invention to promover is inoperative, the reciprocating parts may be moved upwardly or downwardly easily and quickly and without dissipating any of the energy stored in the counterbalancing system.

and connected reciprocating parts during the.

latter half of the downstroke of the pump plunger and to accelerate the pump plunger and connected reciprocating parts during the first hall of the upstroke of the pump plunger. It is an object of my invention to provide a counterbalancingsystem operating by the travel of liquid therein whereby energy'from the pumping apparatus is stored at a sufliciently high rate during the latter half of the downstroke of the pump plunger and its associated parts to decelerate their motion, and is returned to the pump plunger and its associated reciprocating parts at a high rate during the first half of the upstroke of the pump plunger to accelerate their motion.

In one form of my invention, I propose to derive my cpunterbalancing pressure solely from theweight of a column of liquid with no reliance whatsoever on pressure of a confined body of gas. A feature of this form of my invention is that I may have such a column vary in horizontal cross-sectional area within the range of levels through which the liquid level reciprocates during pump action, so that the ratio of energy transmittedto or from the liquid column to the volume of liquid simultaneously transmitted to or from the column will vary in the course of the operating cycle. In other words, I propose to take advantage of the fact that the liquid level will rise relatively rapidly with correspondingly rapid increase in counterbalancing pressure if the liquid level is rising through a relatively restricted channel and vice versa. For example, the rate of energy transmission to the liquid column pervolume of liquid displaced may be sharply increased toward the end of the downward pump stroke .dissipating the energy of momentum of the various working parts involved, energy being returned to the pumping apparatus at the same high rate in theearly part of the upward pump stroke to accelerate the reciprocating mechanism. A further feature of the form of my invention that utilizes solely the weight of a liquid column for counterbalancing is that the liquid-containing means for forming the column may be constructed for adjustable variation in vertical configuration to provide for adjustable control of the mean height of the liquid level.

and for adjustable control of the rate at which the liquid level rises or falls at various points of the cycle of pump operation.

Another object of my invention is to provide apparatus, as hereinbefore described, that may be inexpensively constructed and quickly and easily installed upon existing pumping apparatus.

'lhese and other'cbjects and advantages will be "made apparent in the following description, which may be better understood in the light of the accompanying drawings, inwhich:

.. 70 sure chamber.

Fig, 1 is an elevational view, partially sectioned, of the counterbalancing apparatus of my invention;

Fig. 2 is a fragmentary side elevation on an enlarged scale of auxiliary pumps and associated pipe connections which may be substituted for the auxiliary pump means in Fig. 1;

Fig. 3 is an elevational view of an alternative embodiment of my invention;

Fig. 4 is a fragmentary sectional view showing one configuration for the upper end of the liquid chamber of Fig. 2;

Fig. 5 is a fragmentary elevational view partly in section showing another configuration for the upper end of the liquid chamber of Fig. 2;

Fig. 6 is a vertical axial section on an enlarged scale of an adjustable liquid chamber which may be substituted for the liquid chamber of Fig. 4;

Fig. 7 is a side elevation partly in section of 29 a second form of adjustable liquid chamber; and

Fig. 8 is a fragmentary side elevation of a third form of adjustable liquid chamber comprising a flexible tube.

Referring to the drawings, which are for illustrative purposes only, the numeral H indicates an oil well having therein a casing 12 and a pump tubing iii, in the lower end of which tubing a pump plunger I4 is reciprocated by a string of sucker rods l5. Connected to the upper end of the string of sucker rods l5'is a polished rod l6 which extends through the casing head and is attached to a cable ll, the cable being secured to a mule-head H8 at one end of a walking-beam N. The other end of the walking-beam i9 is mounted upon a pivot 20 on a Sampson post 2!. Se-

cured to the walking beam l9 intermediate its ends is a pitman 22, the lower end of which is attached to a. crank 23 mounted upon a crankshaft 24.

' A crank-shaft gear 25 is secured to the crankshaft 24. The crank-shaft gear 25 is driven by a countershaft gear 26 through a chain 21. The countershaft gear 26 is carried by a countershaft 28 which supports a driven gear 29. The driven gear 29 is rotated by a drive-shaft 30 through a chain drive 3!, the drive-shaft 30 being rotated by a prime mover 32 which may be a steam engine, a gas engine, or the like. When the prime mover is energized, the drive-shaft 30 is rotated,

thus rotating the driven gear 29, the crank-shaft gear 25 and the crank 23'whereby the pitman 22 oscillates the walking-beam [9 about the pivot 20 and raises and lowers the pump plunger [4 in the well.

Swingably secured to the walking-beam I9 is a connecting rod 33, the other end of which is swingably mounted in a piston 34. The piston 34 is slidably disposed in a cylinder 35 open at its upper end to the atmosphere and communicating at its lower end with a housing or conduit 36. The connecting rod 33 carries a cylindrical hood 3'. extending over the open upper end of the cylinder 35. The piston 34 and cylinder 35 may be regarded as two members forming a working chamber.

The conduit 36 communicates with a chamber 38 which is connected by a pipe 39 with a reservoir 40. The chamber 38, either alone or together i with the reservoir 40, may be regarded as a pres- A manual valve 4| is disposed in the conduit 36 so that communication may be -shut ofi between the cylinder 35 and the chamber 38. and the pipe 39 is likewise provided with a "Lflmanual' valve 42. 7g is? no counterbalancing apparatus is employed,

it will be seen that, upon the upstroke of the pump plunger l4, it is necessary for the prime mover to lift the walking-beam l9 with the pitman 22, the string of sucker rods l5, the pump plunger l4, and the weight of a column of liquid 5 extending from the pump plunger It to the surface of the ground. On the downstroke of the pump plunger l4, all of these reciprocating parts of the pump mechanism tend to fall by gravity. Thus, without a counterbalancing apparatus, the 10 load upon the prime mover during the upstroke of the pump plunger I4 is enormously greater than the load thereon during the downstroke of the pump plunger.

The interior of the cylinder 35 below the piston 15 34, together with the conduit 36 and a portion of the chamber 38, are filled with liquid, there being a closed gas space above the liquid level 43 in the chamber 38 and in the reservoir 40. Gas in this space may be compressed to an extent 20 to exert through the liquid, the piston 34, and the connecting rod 33 a counter-clockwise moment upon the walking-beam l9 equal to the clockwise vmoment imposed thereon by the weight of the pressure in the gas space in the chamber 38, the :10

gas in the chamber 38 and the reservoir 40 may be compressed to an additional degree during the downward movement of the walking-beam l9 and the downstroke of the plunger l4, thereby imposing upon the prime mover 32 a load substantially 3 equal to one-half of the load imposed by the column of liquid in the pump tubing l3 during the upstroke of the plunger M. This work of the prime mover 32 during the downstroke of the pump plunger I4 is stored in the compressed gas 40 and returned to the pumping apparatus during the succeeding upstroke of the pump plunger I4, assisting the prime mover 32 in lifting the column of liquid in the pump tubing l3, so that the load upon the prime mover during this upstroke 45 is substantially equal to one-half of the weight of the column of liquid in the pump tubing l3.

In this manner, the loads upon the prime mover in the upstroke and downstroke of the pump plunger l4 are substantially equalized, approxi- 50 mately one-half of the weight of the column of liquid in the pump tubing l3 being effective at the end of the walking-beam l3.

If the prime mover 32 is inoperative and it is desired to move the walking-beam I9 and its connecting parts, such movement may be easily accomplished and accurately controlled by means incorporated in the apparatus of my invention now to be described.

A liquid pipe 44 is connected to the conduit 0 36 adjacent the cylinder 35 and to the inlet side of a liquid pump-45. The liquid pipe 44 has therein a manual valve 46 and a check valve 4! adjacent the pump 45. The check valve 4'! may be of any convenient construction, such as a ball 5 valve, which will prevent the passage of liquid from the pump 45 through the liquid pipe 44 toward the conduit 36. The pump-45 may be of level 43 therein. L The pipe 50 includes a manual valve adjacent the chamber 36 and a check valve 52 adjacent the pump 45. The check valve 52 is similar in construction to the check valve 41 and is designed to prevent the passage of liquid through the liquid pipe 50 toward the pump 45.

A liquid pipe 53 has one end connected to the chamber 38 below the liquid level 43 therein and the other end connected to the liquid pipe 44 between the manual valve 46 and the check valve 41. A three-way valve 54 is adapted to be moved between one position providing communication between the pipe 44 and the pipe 53 and another position cutting off communication of the pipe 53 with the pipe 44 but not interfering with flow through the pipe 44. Another liquid pipe 55 has one end connected to the liquid pipe 44 between the valve 46 and the conduit 36 and its other end connected to the liquid pipe 50 between the manual valve 5| and the check valve 52. A three-way valve 56 is adapted to be moved between a position permitting communication between the pipe 50 and the pipe 55 and a second position cutting oi the pipe 55 from the pipe 50.

If the prime mover 32 is inoperative, the valve 4| in the conduit 36 may be closed. The pressure on the liquid in the conduit 36 on the two sides of the valve 4| is now substantially equal. It, now, it is desired to raise the walking-beam l9 and the pump plunger l4, the valve 46 in the liquid line 44 is closed, the valve 5| in the liquid line 56 is closed and the valves 54 and 56 are positioned for flow through the pipes 53 and 55 respectively. If the lever 49 of the pump 45 be then actuated, liquid under pressure will be pumped from the chamber 38, through the liquid line 53, past the check valve 41, through the pump, 45, past the check valve 52, and through the liquid line 55, and a portion of the liquid line 44 into the conduit 36 adjacent the cylinder 35, thus forcing the piston 34 upwardly. This upward movement of the piston 34 moves the walking-beam l9 and its connected parts upwardly.

While the valve 4| is closed, it is also possible to set the valves to operate the pump 45 to transfer liquid in the opposite direction to permit the walking-beam l9 and the various parts connected therewith to move downward. Thus, if the three- way valves 54 and 56 are closed to cut off pipes 53 and 55 respectively, and valves 46 and 5| are open, operation of the pump 45 will cause liquid to move through the pipe 44, valves 46, 54, and 41, pump 45, pipe 50,, valves 52, 56, and 5| to the pressure chamber 38. It is apparent, then, that the pump 45 and its associated pipes and valves comprise a reversible pumping means for controlling the disposition of the reciprocating mechanism during cessation of pumping operation,- and that the control of the reciprocating mechanism, being achieved by strictly hydraulic means, is exceptionally ac curate.

It will be noted that such adjustment during cessation of pumping operation merely afiects the distribution of liquid in the system, not the total amount of gas or liquid in the system. As soon as the valve 4| is opened, normal liquid distribution and normal pressure against the piston 34 are established automatically.

A power-driven pump may be incorporated in the reversible pumping system in parallel with the manual pump 45, as indicated in Fig. 2. A rotary pump 60 is shown driven by a suitable motor 6|. A pipe 62 branching from the pipe 44 between the check valve 41 and the threeemployed for the same purpose.

,ancing pressure. piston in the cylinder 35a on the downstroke of way valve 54 communicates with the inlet side of the rotary pump 66 and is provided with a suitable check valve 63. The outlet side of the rotary pump 60 is connected by a pipe 64 with the pipe .50 betweenthe pump 45 and the check valve 52. It will be apparent that either the hand pump 45 or the electric pump 60 may be In practice. the electric pump is utilized for any extensive transmission of liquid, and the hand pump 45 is utilized to cause minor movements of liquid when fine adjustment is necessary.

-In the form of my invention above described, hydraulic means is incorporated in the counterbalancing system, but the counterbalancing pressure is derived primarily from the pressure of a confined body of gas. A feature of other forms of my invention is that the counterbalancing pressure is derived solely from the weight of a column of liquid, with incidental atmospheric pressure, but with no reliance whatsoever upon the effect of a confined body of gas. For an example of such construction, attention is directed K to Fig. 3 in which the pressure chamber includes a vertically extensive tube 66 supported by the derrick framework 61 of the well, the tube'being open to the atmosphere at its upper end.

This tube replaces the chamber 38, the pipe 39, and the reservoir 40 of Fig. 1, but the remaining parts of the apparatus are identical with the corresponding parts of Fig. 1, being designated by corresponding numbers with the sufiix a.

The tube 66 is of such vertical type that hydraulic pressure against the'piston in the working chamber 351; is of the required magnitude to provide the desired counterbalancing eiiect. It

will be-apparent that, in eliminating the confined gas body, I avoid all the problems incidental to maintaining gas pressure, and that the counterbalancing pressure may be readily varied by simply changing the volume of liquid in the tube 66, thereby changing the height of the column.

The minimum height of the liquid column, when the piston in the cylinder 35a is at its uppermost position, will, of course, be the height necessary to result in the desired counterbal- Downward movement of the the well pump will introduce an additional volume of liquid into the tube 66 and cause the liquid level in the tube to rise, with consequent increase of the counterbalancing pressure. The rate at which the liquid level is raised in the tube 66 controls, of course, the rate at which energy is stored in the counterbalancing system and the smaller the cross-sectional area of the channel through which the liquid level rises, the more rapid the rate of pressure increase per unit volume of liquid displaced.

A feature of the forms of my invention utilizing the weight of such a liquid column for counter-,

balancing purposes is that the manner in which the counterbalancing pressure fluctuates during the pump cycle may be readily controlled by simply changing the configuration of the channel through which the liquid level at the top of the liquid column fluctuates. I imize the rate of pressure change and the range through which pressure fluctuates, the upper end of the tube 66 may communicate, as shown in Fig. 4, with a laterally extensive tank '68. In employing such an arrangement for example, the minimum counterbalancing pressure may be provided by the weight of liquid in the tube 66, the liquid level fluctuating within the confines of the tank If it is desired to min- 68 as determined by the volume of liquid displaced by the piston in the working chamber 35a.

On the other hand, the channel through which the counterbalancing liquid column fluctuates in the course of pump operation may be restricted to cause a relatively high rate of pressure change, for example, as shown in Fig. 5 in which a pressure tube 66b terminates in an open-end pipe 10 of restricted diameter.

The manner in which the counterbalancing pressure will change, if the construction shown in Fig. 5 is employed, will depend upon the range of levels in which the liquid level reciprocates. If, in the course of a pumping stroke, the top of the liquid column fluctuates between the level 12 and the level 13, the rate in change of counterbalancing pressure will be uniform. If the top of the liquid column fluctuates between levels 14 and I5, the rate of change will again be uniform but much higher. If the-range of liquid level fluctuation is between levels 13 and 1'4, the rate of pressure rise per unit volume of liquid displaced will increase during the later part of the downward Pump stroke and the early part of the upward pump stroke. The increased resistance to movement of the reciprocating mechanism caused by the rapid rise of counterbalancing pressure may have a substantial and useful braking efiect upon the movement of the reciprocating mechanism, the liquid system absorbing the energy of momentum of the reciprocating mechanism. It is especially desirable to increase the rate of pressure rise per unit volume of liquid transmitted at this point in the pump stroke because the crank 23 is approaching dead center and the rate of liquid transmission is falling off rapidly. It is apparent that the liquid channel may be sufilciently restricted to more than offset the slowing down of the rate of fluid transmission in the counterbalancing system. At the beginning of the subsequent upstroke of the reciprocating mechanism, considerable energy is required to overcome the inertia of the pumping mechanism combined with the inertia of the column of oil in the well tubing, and the energy .previously stored in'a liquid system in the deceleration of the pumping mechanism now becomes efiective to overcome this combined inertia.

In the last-mentioned arrangement in which the upwardly rising liquid column enters a restricted passageway in the course of the downward pump stroke, it may be desirable to provide some means of adjusting the point in the pump stroke at which the higher rate of pressure change is initiated. This end may be accomplished by making the liquid-pressure tube adjustable in effective configuration. For example, an arrangement of telescoping-tubes: may be employed, as indicated in Fig. 6, in which a relatively small tube 18 is adjustably mounted in the upper end of a pressure tube 660 corresponding to the tube 68 of Fig. 3. The tube 18, being open at both ends, extends into the tube 660 and is embraced near its lower end by a suitable piston 19 in sliding engagement with the inner wall of the tube 68. At the upper end of the tube 68, a bushing threaded to the tube 66 embraces in a freely slidable manner the tube 18 and is provided with suitable means, such as a setscrew 8|, for releasably engaging the tube 18. A packing gland 82 may be provided, if desired.

Another construction for a liquid-pressure means providing for adjustable variation in the eflective cross-section thereof may be understood by referring to Fig. 7. In this particular form of my invention, the liquid-containing means defin ing the counterbalancing liquid column includes a flexible tube or hose 85 in communication with the working chamber of the counterbalancing system. The flexible tube 85 communicates with an inlet port 86 in a liquid tank 81, which tank is suspended from a derrick 88. The tank may be adjustably suspended, for example, by a rope or cable 89 passing over a sheave 90 on the crownblock 9| of the derrick. The drawings show the cable 89 terminating in a yoke 93, from which short cables 94 extend to the tank. It is contemplated in this arrangement that the liquid level of the counterbalancing liquid body will fluctuate within the range of levels occupied by the tank 81 to provide for variation in the rate of pressure change per unit volume of liquid displaced. It is necessary only to place in the tank some body of the required shape to cooperate with the tank in defining the liquid configuration desired. Such a body may be simply a concrete block 95. If it is desired that the rate of pressure rise change sharply from one uniform rate to another uniform rate in the course of a pump stroke, the concrete body may be rectangular in cross-sectional configuration as shown. To provide for conveniently controlling the depth to which the concrete block 95 is immersed in the liquid body 96 in the tank, thereby to control the efiective cross-sectional configuration of the liquid column, the concrete block 95 may be suspended by a cable 91 that passes through an aperture 98 in the yoke 93 and passes-over a sheave 99 at the top of the derrick. It is apparent that by manipulating the cables 89 and 91 from the derrick floor, an operator may regulate the height of the tank 81 to control the mean counterbalancing pressure and may regulate the position of the concrete block relative to the tank 81 to determine the points in the cycle of pump operation at which changes are to occur in the rate of pressure change per unit volume of liquid displaced.

Another flexible arrangement for a liquidpressure counterbalance permitting ready control of the liquid column configuration is shown in Fig. 8. In this form of my invention the liquid counterbalancing system includes a flexible tube or hose I00 containing at least the upper part of the liquid column that exerts the counterbalancing pressure. Since the rate of pressure change per unit volume of liquid transmitted to or from the hose I00 will depend upon the angle at which the hose is disposed within the range of liquid level fluctuation, this form of my invention permits exceptionally flexible control. The hose may be disposed at an angle close to horizontal for minimum variation in pressure and may be disposed vertically to provide maximum pressure variation per unit volume of liquid displacement. Thus, the hose may be carried up the derrick of the well a sufllcient distance to provide the required minimum counterbalancing pressure, then disposed at a slight inclination to pr ide minimum pressure variation during the early part of the downstroke of the well pump, and finally turned vertically upward to provide relatively rapid increase in pressure per unit volume of liquid displaced towards the end of the well pump downstroke for the purpose of decelerating the pumping mechanism, as heretofore stated.

In Fig. 8 the vertical portion H of the hose provides the minimum counterbalancing pressure, the lowermost liquid level, for example, being at I02. During the early part of the downward pump stroke, the liquid column rises to occupy the slightly inclined portion I03 of the flexible hose with relatively little increase in the pressure head. Towards the end of the downward pump stroke, however, the liquid is forced into the vertical portion I04 of the flexible hose where the efiect of liquid displacement is accentuated. The hose may be readily adjusted for a wide range of rates of pressure change and the changes in the rate may be as sharp or gradual as desired.

My invention includes not only the illustrative forms specifically described herein, but also all changes and modifications of those forms and all other embodiments that properly come within the scope of my appended claims.

I- claim as my invention:

1. In an oil well pumping apparatus, including a beam member supported for oscillation, pump means in a well, connecting means extending from the beam member to the pump means, and drive means for oscillating the beam member,

the combination of a primary member; a sec- I ondary member connected to the beam member and cooperating therewith to close a fluid chamber variable in volume in response to the oscillation of the beam member and containing fluid compressed to substantiallycounterbalance the weight of the oscillating and reciprocating parts and one-half the weight ofthe liquid lifted by a pump plunger and reciprocating parts, the

combination of: a primary member; a second- 1 ary member associated with the reciprocating parts whereby said secondary member is moved by the reciprocating parts, said secondary member cooperating with said primary member in forcing a liquid under pressure in one direction to store energy from the pumping apparatus during the downstroke of the pump plunger and in returning energy to the pumping apparatus during the upstroke oi'the pump plunger by the flow of liquid in the opposite direction; closure means for interrupting the flow of liquid; and control means for pumping such liquid under pressure from either side of said closure means to the other during such interruption.

3. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the com- -bination of: a primary member; a secondary member associated with the reciprocating parts whereby said secondary member is moved by the reciprocating parts, said secondarymember cooperating with said primary member in.forcing a liquid under pressure in one direction to store energy from the pumping apparatus during the downstroke of the pump plunger and in returning energy to the pumping apparatus during the upstroke of the pump plunger by the flow of liquid in the opposite direction; closure means for interrupting the flow of liquid in both directions; and manually operable control means for pumping such liquid under pressure from either side of said closure means to the other during such interruption.

4. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a comm cat-= ing working chamber; means varying the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by passing liquid under pressure from said working chamber to said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by passing liquid under pressure from said pressure chamber to said working chamber during the upstroke of said pump plunger; means for closing communication between said chambers to maintain the pump plunger stationary; and meansfor moving the pump plunger and reciprocating parts while maintaining pressure on the liquid in said pressure chamber comprising means for passing liquid between said pressure chamber and said working chamber.

5. In anoil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of a liquid circulating system including a pressure chamber containing gas and a liquid and a communicating working chamber containing liquid; means varying the volume of the working chamber in response to the reciprocation of the. pump plunger, whereby energy from the pumping apparatus is stored by passing liquid under pressure from said working chamber to said pressure chamber compressing the gas passing liquid between said pressure chamber and said working chamber. I

6. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the

combination of aliquid circulating system including a pressure chamber and a communicating working chamber, both of said chambers containing liquid; means varying. the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by raising the liquid in said pressure chamber during the downwardstroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber and its passage into said working chamber during the upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts; means for closing communication between said chambers to maintain the pump plunger stationary; and means. for moving the pump plunger and reciprocating parts comprising means for passing liquid into or out of said working chamber. g

7. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the

combination of: a liquid circulating system including a pressure chamber and a communicating working chamber; means varying the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by passing liquid Y under pressure from said working chamber to stroke of the pump plunger and energy is returned to the pumping apparatus by passing liquid under pressure from said pressure chamber to said working chamber during the upstroke of said pump plunger; means for closing communication between said chambers to maintain the pump plunger stationary; and means for moving the pump plunger and reciprocating parts while maintaining pressure on the liquid in said pressure chamber comprising a liquid by-pass connecting said chambers around said closing means and valve means in said by-pass.

8. In an oil well pumping apparatus, including a pump plungerv and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicating working chamber; means varying the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by passing liquid under pressure from said working chamber to said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by passing liquid under pressure from said pressure chamber to said working chamber during the upstroke of said pump plunger; means for closing communication between said chambers to maintain the pump plunger stationary; and means for moving the pump plunger and reciprocating parts while maintaining pressure on the liquid in said pres sure chamber comprising a liquid by-pass line connecting said chambers around said closure member, a liquid pump connected to said line, and valve means in said line.

9. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicatingworking chamber; means varying the volume of the working chamber in response to the reciprocation of thepump plunger, whereby energy from the pumping apparatus is stored by passing liquid under pressure from said working chamber to said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by passing liquid under pressure from said pressure chamber to said working chamber during the upstroke of said pump plunger; means for closing communication between said chambers to maintain the pump plunger stationary; and means for moving the pump plunger and reciprocating parts while maintaining pressure on the liquid in said pressure chamber comprising a liquid pump having connections from its inlet to both of said chambers and connections from its outlet to both of said chambers and valves in said connections whereby liquid may be pumped from either of said chambers into the other of said chambers.

10. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicating working chamber, both of said chambers containing liquid; means varying the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by raising liquid in said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said storage chamber and its passage into said working chamber during the.upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts, said pressure chamber having a cross-sectional area varying at different levels whereby the rate of travel of the liquid level in said pressure chamber is increased during the later part of the downstroke and the early part of the upstroke of the pump plunger to decelerate and accelerate such pump plunger; means for closing communication between said chambers to maintain the pump plunger stationary; and means for moving the pump plunger and reciprocating parts comprising means for passing a manually controlled quantity of liquid between said pressure chamber and said working chamber.

11. The combination with a reciprocating pumping apparatus or the like of counterbalancing means, comprising: a liquid chamber open to the atmosphere and forming a liquid column of sufiicient vertical extent to develop a desired counterbalancing pressure solely by the weight of the liquid column and the weight of the atmosphere thereon; and means to transmit pressure from said liquid chamber to said apparatus.

12. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicating working chamber, both of said chambers containing liquid; and means varying the volume of the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by raising liquid in said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber and its passage into said working chamber during the upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts, said pressure chamber varying in horizontal cross-sectional area at difierent levels whereby the rate of travel of the liquid level in said pressure chamber relative to the rate of change of liquid volume therein and the resultant rate in energy storage or release is varied during the reciprocation of the pump plunger.

13. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicating working chamber, both of said chambers containing liquid; and means varying the volume oi. the working chamber in response to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by raising liquid in said pressure chamber during the downward stroke 01 the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber and its passage into said working chamber during the upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts, said pressure chamber being adjustably variable in effective cross-sectional configuration whereby the rate of travel of the liquid level in said pressure chamber relative to the rate of change of liquid volume therein and the resultant rate of energy storage or release may be varied during reciprocation of the pump plunger.

14. In a counterbalancing apparatus for pumping oil wells, including a reciprocating pump plunger in a well, reciprocating connecting elements, and counterbalancing means operable by passing liquid under pressure back and forth between a pressure chamber and a working chamber adapted to transmit counterbalancing pressure to said connecting elements, means for controlling the disposition of said pump plunger and saidconnecting elements during cessation of pumping operation, said controlling means including: means for cutting ofi normal liquid communication between said pressure chamber 10 and working chamber; a liquid pump; means providing passages from the inlet side of said pump to said pressure chamber and said working chamber respectively and from the outlet side of said pump to said pressure chamber and working chamber respectively; and valve means controlling said passages whereby said pump may be operated to transfer liquid in either direction between said pressure chamber and said working chamber.

15. In an oil well pumping apparatus, includliquid in said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber and its passage into said working chamber during the upstroke of said pump plunger to substantially counterbalance the pump plunger'and reciprocating parts, said pressure chamber varying in cross-sectional area at different levels whereby the rate of travel of the liquid level in said pressure chamber and the resultant rate in energy 40 storage or release is varied during the reciprocation of the pump plunger; means for closing normal communication between said chambers during cessation of pumping operation to maintain said pump plunger and said reciprocating parts stationary; and means for moving the pump plunger and reciprocating parts during cessation of pumping operation comprising means for pumping liquid into or out of said working chamber. 7 5o 16. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system including a pressure chamber and a communicating working chamber, both of said chambers 5 containing liquid; and means varying the volume of the working chamber inresponse to the reciprocation of the pump plunger, whereby energy from the pumping apparatus is stored by raising liquid in said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber and its passage into said working chamber during the upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts, said pressure chamber being of telescoped construction to provide adjustable variation in the effective configuration 70 thereof whereby the rate of storage of energy from and return of energy to the pump plunger and reciprocating parts may be varied.

17. In an oil well pumping apparatus, including a pump plunger and reciprocating parts, the combination of: a liquid circulating system 5 including a pressure chamber and a communicating working chamber, both of said chambers containing liquid; and means varying the volume of the working chamber in response to reciprocation of the pump plunger, whereby energy 10 from the pumping apparatus is stored by raising liquid in said pressure chamber during the downward stroke of the pump plunger and energy is returned to the pumping apparatus by the falling of the liquid in said pressure chamber during 15 the upstroke of said pump plunger to substantially counterbalance the pump plunger and reciprocating parts, said pressure chamber being relatively restricted in horizontal cross-sectional area in the range of liquid level movement cor- 20 responding to the latter part of the downward stroke ofthe pump plunger whereby energy is in such later part of the downward stroke stored in the pressure chamber at a relatively high rate per unit volume of liquid displacement to de- 25 liquid chamber including a flexible conduit to permit adjustment in the height and configuration of the liquid column; and means totrans- 40 mit pressure from said liquid chamber to said apparatus.

19. The combination with a reciprocating pump apparatus or the like of counterbalancing means, comprising: a liquid chamber open to 45 the atmosphere and forming a liquid column of sufiicient vertical extent to develop the desired counterbalancing pressure solely by the weight of the liquid column and the weight of the atmosphere thereon; means within said chamber 50 cooperative therewith to determine the con-, figuration of the liquid column and causing the liquid column to change in horizontal crosssectional area within the range of liquid level fluctuation; and means to transmit pressure from said liquid chamber to said apparatus.

20. The combination with a reciprocating oil well pumping apparatus and an oil well derrick of counterbalancing means, said counterbalancing means comprising: a liquid chamber open to the atmosphere andforming a liquid column of sufiicientvertical extent to develop a desired counterbalancing pressure solely by the weight of the liquid column and the weight of the atmosphere thereon, at least a portion of said chamber being adjustably mounted on said derrick to permit adjustment in the height of the liquid column; and means to transmit pressure from said liquid chamber to said apparatus.

' WALTER E. SAXE. l0

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