US2293915A - Counterbalanced pumping unit - Google Patents

Description

Aug. 1942- E. w. PATTERSON 2,293,915

COUNTERBALANCED PUMPING UNIT Filed Sept. 25, 1939 gamma L01 sa -a1- WPaiiersazz Patented Aug. 25, 1942 COUNTERBALANCED PUMPING UNIT Edgar W. Patterson, Long Beach, Caliifi, assignor of one-half to M. D. Patterson, Long Beach, Calif., and one-half to Charles M. OLeary, In,

Los Angeles, Calif.

Application September 25, 1939, Serial No. 296,501 '6 Claims. (Cl. 74-589) The present invention relates generally to well pumping units, and more particularly to fluid balanced units of the type disclosed in my prior application Serial Number 50,540, filed November 19, 1935.

In my above application I proposed the utilization of an air balance controlled by air pressure from a receiving tank or reservoir which was supplied with pressure by a compressor operated by the walking beam of the unit, the compressor including an arrangement whereby air is merely compressed and expanded in alternationtherein when it is not supplying air to the reservoir, for instance when the latter is at or above the normal operating pressure desired for proper action of the counterbalance.

I also proposed in my above application an arrangement whereby compression strokes of the compressor coincide with compression strokes of the air balance so that the compressor, when not acting to compress air in the reservoir as when pressure therein is at or above the desired maximum, will alternately compress and permit expansion of the same air therein and will to a substantial extent supplement the air balance or in other words augment its practical effect and assist the same in its work.

It is the primary object of my present invention, in continuation of, and supplementing the above described arrangement of my previous application, to further simplify and improve the pumping unit as a whole by a reduction in the number of necessary parts, and particularly by substituting for the air balance and separate compressor, a compressor, which may be of the same type, but with a capacity and connections adapting and permitting the same to act fully and efiectively as the air balance of the unit between those infrequent periods during which it is required to compress air into the receiving tank or reservoir to bring the latter to the desired maximum.

To accomplish the foregoing it is preferable to employ a compressor of the type shown in my above mentioned application, mounted, connected, and of a capacity, to quickly compress air at the start of operations and during those periods in which it is necessary for this dual functioning element of the unit to act as a compressor, with the object of shortening such periods as far as it is possible to do so and permitting this element to function as a full complete balancing means for the unit during all other periods of use.

With the above in mind, the further objects,

as well as the resulting advantages of the invention will be better understood and more thoroughly appreciated in the course of the following detailed description, and by reference to the accompanying drawing, which forms a part of this specification, and in which,

Figure 1 is a side view of the complete unit.

Figure 2 is a vertical transverse sectional view through the combined compressor and air balance, showing its connections with the rocking beam.

Figure 3 is a vertical longitudinal section through a portion of the cylinder on line 33 of Figure 2, and

Figure 4 is a view showing in detail one of the fluid connections between the compressor and reservoir.

Referring now to these figures and particularly to Figure 1, there is illustrated a pumping unit of the type contemplated by the present invention, including a sub-frame l0. Carried by this sub-frame is a base unit which includes a receiving tank ll and structural frame members l2 rigidly connected therewith. Mounted upon this base unit is a power unit 13 which includes any suitable driving motor or means, plus gear reduction means through which a shaft I4 is driven. Secured on the shaft I4 is a crank disk l5 and this crank disk is preferably provided with a crank pin it and with an annular series of crank pin receiving openings i6 successively spaced greater distance throughout the series from the axis of crank disk IE to thus provide for adjustment and disposition of the crank pin in a selected opening in order to regulate the length of throw-of the crank.

Engaging the crank pin 16 is the lower end of a. connecting rod H, the upper end of which is connected by a pivot at Hi to a cross head carried by the rocking beam l9 at approximately the central portion of the latter. The beam [9 is preferably pivoted at one end, for vertical swinging movement, upon a fulcrum shaft 20 supported at the upper end of a vertical Samson post 2|. This post 2|, as shown, upstands from the base structure to which it may be suitably secured as by means of bolts 22. The outer free end of the rocking beam [9 may be provided with the usual horse head 23 having a segment 24 over which the usual reins of a pump polish rod are extended in order that the up and down swinging movements of the free end of beam l9 will be communicated to a pump polish rod in the usual manner.

The rocking beam cushioning and counterend of the beam and the point at which the power actuating connections are secured thereto.

This combined air balance and compressor is preferably in the nature of the compressor of my application above referred to, though of considerably greater capacity, and is shown in Figures 1 and 2 as comprising a cylinder 36, the lower end of which is provided with an axial extension supporting a. cross shaft 3|. This cross shaft is movably disposed in bearings 32 suitably secured to and resting on the structural frame members l2 of the base unit.

The cylinder 36 which is thus mounted at its lower end to swing toward and away from the Samson post 2| below and in the plane of the rocking beam I3, is closed at its base except for an axial port 29 leading therefrom through its above mentioned axial extension and communicating with a bore 36 extending therefrom through one end of the cross shaft 3|, as shown particularly in Figure 2 so that air thus passes into and out of cylinder 36 through port 29 and bore 36 at the lower pivoted end of the cylinder which is its point of least oscillation. The outer end of bore 30 of the cross shaft 3| is at all times in communication wtih one end of a pipe 33 connected thereto and having therein adiacent to the shaft, fittings 33 permitting ready oscillation of that portion of the pipe connected to the cross shaft 3|. The opposite end of pipe 33 is connected to the receiving tafik or reservoir II. This pipe 33 is provided with a manually operated controlling valve 34 located therein adjace'nt to the tank or reservoir II for a purpose which will presently appear.-

The combined compressor and air balance includes the cylinder 36 and an upstanding piston rod 40, cylinder 36 being formed with a packing gland 33 at its upper end through which the said piston rod extends and is operable. The gland 33 is preferably of considerable length as shown in order to offset any tendency of the rod toward lateral displacement. On the lower end of the rod 46, within cylinder 36, is a piston 4|.

At the upper end of piston rod 40 is a U-shaped bracket 42, the upstanding arms of which straddle the rocking beam I3 and support upper bearings 43 receiving the ends of a pivot pin 44 suitably carried by the web of the rocking beam II. This connection is made as before stated at a point on the rocking beam between its free end and the pivotal connection I 6 of the power means. The piston rod 40 is threaded at its upper end centrally through the base of bracket 42 in order that it may be rotated for adjusting the position of the piston 4| in the cylinder 36. This threaded upper portion of the rod is provided with a jam nut normally bearing tightly against bracket 42 to prevent the above mentioned adjustment from working loose.

The above mentioned piston 4| and cylinder 36 are thus adapted, by the adjustment of the position of the former within the latter, to feed any desired pressure of fluid into the tank or reservoir during action of the cylinder as a compressor and to subsequently maintain such pressure at any stroke length of the pumping unit,

change in the length of the pump stroke following the shifting of the-crank pin i6 from one of the openings l6 of crank disk I5 to another. As a pressure supplying connection between the base of cylinder 36 and the tank or reservoir II, I preferably utilize a pipe 54, as best seen in Figure 2 in a manner to form a by-pass around the manual valve 34, this pipe 54 being connected at its opposite ends to the previously mentioned connecting pipe 33, at spaced points of the latter, with one end of pipe 54 in communication with pipe 33 at a point between valve 34 and the tank or reservoir. As also best seen in Figure 2, the pipe 33 has intermediate its ends a lateral pipe provided with an intake check valve 5| through which air'may be taken into the pipe. Pipe 54 has a check valve 53 therein which opens toward the reservoir so that with valve 34 closed air may be pumped from the base of cylinder 36 through a portion of pipe 33 and through pipe 54 into the tank or reservoir during the down-stroke of piston 4|. During the upstroke of the piston air will be drawn into the base of the compressor through pipe 50 and intake valve 5| and thence through the upper portion of pipe 33.

The piston 4|, as is plainly shown in the several figures, operates intermediate the ends of cylinder 36 to thus divide the latter into an upper compression space or chamber 56, between the piston and the upper closed end of the cylinder, and a lower compression space or chamber 51 between the piston and the base of the cylinder. Obviously the lower compression space has two-way communication with the tank or reservoir II when valve 34 is open and but one-way communication therewith as above described when valve 34 is closed, so that air may be quickly pumped into the reservoir.

In order that the pressure may be compounded, there is connected at the upper portion of the upper compression space or compartment 56 of the cylinder 36 a pipe 53 opening therein immediately below the upper end of the cylinder defined by the inner end wall 58 of the packing gland 39. A,T-connection 66 is attached to the pipe 53 in order to couple thereto a lateral leg carrying a stopcock 6|. A second T 62 is connected to pipe 53 and beyond this T the pipe carries a check valve 63 through which air may be drawn into the pipe and at the same time checked from flow in the opposite direction.

Connected to one leg of the T 62 is a pipe 64 depending along the cylinder 36 and provided at this same adjustment compensating for any its lower end with an elbow 65 and a lateral pipe provided therein with a check valve 66. The lateral pipe 61 in which check valve 66 is connected, extends through the wall of the cylinder 36 at a point where it will be covered on the lower portion ofthe downstroke of I the piston 4| and uncovered during a portion of the upstroke of the piston. Check valve 66 permits the flow of fluid from pipe 64 through pipe 61 into the cylinder but prevents the flow of fluid in an opposite direction.

It will be understood that the valve 5| while functioning to prevent discharge of pressure from the lower chamber of cylinder 36, will allow inflow of fluid to said chamber at any time, either when valve 34 is closed, or when the latter is open and the amount of pressure in the connection between the cylinder and the tank or reservoir permits. The check valve 53 will at all times permit the movement of pressure from the cylinder 36 to the tank or reservoir and is also present to function either when valve 34 is closed or when the latter is open and the air discharge capacity of the cylinder 38 is greater than the then existing pressure within the reservoir. Thus it should be noted there will. be no tendency to build up heat in the unit, since after the desired pressure in the receiver or reservoir II has reached the desired maximum, the same fluid, with the valve 34 open, is being compressed and expanded as the piston 4| reciprocates. The valves and piping which establish communication between the upper and lower chambers of cylinder 36 make it possible to supercharge the lower chamber as the piston 4| travels upwardly and this supercharging action is effective or not- 'valves positioned as above. pressure will be rapidly built up in the tank or reservoir ii to the desired maximum. When the desired maximum has been reached valve 34 is then opened so that a full unobstructed two-way communication is thus opened between the lower chamber of the cylinder 36 and the reservoir or tank Ii whereby the pressure in the latter will be the same .as that in the lower chamber of cylinder 36 and this cylinder and its piston and piston rod 40 connected as previously described to the rocking beam I9 will act as a full counterbalance for the latter.

During this operation as a counterbalance and since the pressure in the lower chamber 51 of the cylinder 35 is the same as that of the tank or reservoir, air will be merely compressed and expanded alternately within the upper chamber 55 as long as valve 6! is closed, ready to be forced into the lower chamber 51 at any time pressure in the latter falls below pressure in the upper chamber.

Performance may be varied by adjusting the piston rod 40 with respect to the rocking beam bracket 42, so that the compression spaces 56 and/or 51 within cylinder 36 will be such as to produce the maximum pressure desired. This adjustment is made by loosening the jam nut of rod 50 and turning the rod with respect to bracket 42, the adjustment after being made, being locked by again turning the jam nut tightly against the bracket.

It is evident, therefore, that the piston 4| may be adjusted within the cylinder for varying its position relative to the latter, without effecting its ability to maintain a constant stroke length at any set stroke length of the rocking beam. Thus in providing for adjustment in the relative position of piston 4| in cylinder 35, simple and effective means are present to both compensate for any adjustment which may be necessary in the length of stroke of the rocking beam or in other Words the pump stroke, and to quickly bring the pressure tank or reservoir up to maximum and subsequently maintain said maximum at any length of pump stroke within the range of adjustment thereof.

Under normal conditions at the start of operation, assuming that it is desired to have the piston 4| supply air to the tank without supercharging action, the stopcock 6| is opened and valve 34 of course closed. Thus as the piston 4| moves upwardly to the extreme upper position during which air is taken into the space 51 through valve 5|, pipe 50 and a portion of pipe 33, no air will be forced from space 38 into the said space 51 through pipe 81 and check valve 83 due to the fact that no compression of air can take place in the upper chamber 58 as long as valve 8| is open. On the downstroke of piston 4| check valve 6| closes and the air previously drawn into the space 51 is forced through pipe 33, by-pass 54 and check valve 53 into the tank.

In the event it is desirable to supercharge the fluid, as is usually the case in order to hasten the increase of pressure in the tank to the desired maximum, the stopcock BI is closed. Thus on downstroke of the piston 4|, air will be drawn into the space 58 above the piston through check valve 63 and pipe 59. Since on a portion oi the downstroke of the piston the inner port of pipe 61 is closed by the piston, on the upstroke of piston 4| the air will be drawn in through valve 5| and pipe 50 until the port of pipe 61 is uncovered, that is the piston proceeds above the same. At this time the air previously entrapped within the space 56 above the piston will be compressed, the check valve 83 will be closed, and this air will be forced through pipe 64 and check valve 66 into the space 51 in view of the fact that such air is compressed while the air previously drawn into space 51 is not under compression. Thus at this time the lower space 51 will not only contain the normal volume of air drawn into it through valve 5| but will also contain the air from space 56 which is under a predetermined pressure.

Upon the next downstroke of piston 4| the air, already under compression within space 57 will be further compressed and forced into the receiving tank or reservoir.

Thus by the arrangement shown and described a multistage compression may be obtained which will insure that while the compressor is working as the sole counterbalance of the rocking beam, it will he constantly ready with the stopcock closed to maintain the desired pressure within the receiving tank in order to offset any leakage which might occur in the apparatus.

With the foregoing in mind it is the obvious the invention provides a combined counterbalance and compressor which may be utilized with all of the advantages previously mentioned in order to carry out in an effective manner the objects first above stated and that while the preferred form only of the invention has been illustrated, it will be understood that it contemplates any changed or modified arrangements which may be employed to bring about the same results.

What is claimed is:

1. A counterbalance for a well pumping unit having a power actuated walking beam, said counterbalance comprising a fluid pressure receiver and reservoir, a compressor of a capacity to act as a full air counterbalance for the beam and including a cylinder, a piston therein, and a piston rod rising from the piston above the upper end of the cylinder, said cylinder havin an extension at its base including a rock shaft and having an air channel leading through said rock shaft from the cylinder space below the piston, means movably supporting the rock shaft to permit oscillation of the cylinder thereon, means pivotally connecting the upper end of the piston rod to the walking beam and with which means the rod is in adJustable engagement permitting adjustment of the piston in said cylinder toward and away from the bottom and/or top of the cylinder, and valve controlled air connections between said rock shaft channel and the receiver and reservoir including an air conduit, and means for utilizing said conduit as a one-way passage for fluid pressure from the cylinder when the latter is acting as a compressor, and as a two-way passage between the cylinder and the receiver when the former is acting as a beam counterbalance.

2. A counterbalance for a well pumping unit having a power actuated walking beam, said counterbalance comprising a fluid pressure receiver and reservoir, a combined compressor and air counterbalance including a cylinder closed at its upper end and having a rocking support at its lower end, a piston in said cylinder dividing the same into upper and lower chambers, and a piston rod extending upwardly from said piston through the closed end of the cylinder, means pivotally connecting the upper end of said rod to the walking beam and with respect to which means the rod is adjustable to adjust the piston in the cylinder for varying the chambers above and below the same, valve controlled air connections between the said upper and lower chambers including an air inlet to the upper chamber, and valve controlled connections between the lower chamber of the cylinder and the reservoir including an air conduit, and means for rendering said conduit eflective as a one-way passage for fluid pressure from the cylinder, acting as a compressor, to the receiver, and as a two-way passage between the receiver and the cylinder acting as a beam counterbalance.

3. A counterbalance for use with a pumping unit having a power actuated, vertically oscillating member, said counterbalance comprising a cylinder having a rocking support at its lower end, a piston therein connected at its upper end to the said member, a storage tank for maintaining a definite set pressure, means forming a conduit between said tank and the cylinder below its piston for permitting free passage of air to and fro between the cylinder and tank, a control valve in said conduit for isolating the cylinder from the tank, a pipe connected at its ends to said conduit at opposite sides of said control valve and forming a by-pass around said control valve, a check valve in said by-pass pipe opening toward the tank for permitting passage oi. air from the cylinder to the tank and preventing passage of air from the tank to the cylinder when the control valve is closed, and air intake means for the cylinder effective when the control valve is closed having therein a check valve opening toward the cylinder on the upstroke of its piston for the intake of air and closing on its downstroke for forcing such air into the tank through said by-pass to increase the pressure in the tank when desirable.

4. A counterbalancing device for a well pumping unit having a power actuated member of a type adapted to the actuation of a piston, said device consisting of a combined compressor and counterbalance cylinder, a piston therein dividing the same into a compression space and a working space, the latter forming a balancing chamber of a capacity to receive and maintain maximum predetermined air pressure for substantially counterbalancing said unit by opposing such pressure against the piston in its movements in one direction, valved means forming an air pressure flow channel from the compression space into the balancing chamber and preventing its reverse movement, whereby the maintained pressure in the chamber will equal the maximum out put pressure from the compression space through said channel, valved means admitting air from the exterior into the compression space and preventing its exhaust therefrom whereby the piston will alternately compress air therein and permit expansion of such air when the compression chamber is at maximum maintained pressure, and operative connections between the piston and the power actuated member including means for respacing the piston in its cylinder to thus vary the output pressure 01 the compression space and thereby regulate the maximum maintained pressure within the balancing chamber.

5. A counterbalancing device for a well pumping unit having a power actuated member or a type adapted to the actuation of a piston, said device consisting of a combined compressor and counterbalance including means forming a piston chamber, a piston operatively connected to said power actuated member and arranged intermediate the ends of said piston chamber, forming a compression space therein at one side of the piston and a working space at the opposite side, means in communication with said working space to receive and maintain a predetermined pressure for substantially counterbalancing the unit by opposing said pressure against the piston in its movements in one direction, said compression space having an air intake and a check valve in said intake normally, preventing outlet of air and causing air taken into said space to be alternately expanded and contracted by the piston while pressure in the working space is at a maximum, and connections between said compression space and the working space ior supplying pressure from the former to the latter during movements of the piston in the opposite direction when pressure in the working space falls below said predetermined pressure having a check valve therein preventing movement of pressure from the working space to the compression space.

6. A counterbalancing device for a well pumping unit having a power actuated member or a type adapted to the actuation of a piston, said device being in the nature oi a combined air compressor and counterbalance including means forming a closed piston chamber, a piston therein operatively connected to the power actuated member and dividing the chamber into a compression space at one side of the piston and a working space at the opposite side thereof, said compression space having an air intake and a valve in said intake preventing outflow of air therethrough, a receiver in communication with said working space for receiving and maintaining a predetermined maximum pressure at one side of the piston to substantially counterbalance the pumping unit, the piston alternately compressing and permitting expansion of air taken into the compression space through said intake connections between the compression space and the working space for feeding pressure from the former into the latter whenever pressure therein falls below said maximum pressure having a valve preventing reverse movement of pressure between said spaces, and means for adjusting the piston in its chamber to simultaneously and proportionately vary the relative volumes of said compression and working spaces and control the compression ratio of the said compression space.

EDGAR W. PATTERSON.

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