US2755780A - Hydromechanical pumping jack - Google Patents

Description

July 24, 1956 R. BACCHI HYDROMECHANICAL PUMPING JACK 4 Sheets-Sheet 1 Filed Aug. 19, 1954 Awavroe AZW 544cm W lrranviy July 24, 1956 R. BACCHI 2,755,780

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irraevir HYDROMECHANICAL PUlVlPIN G JACK Ray Bacchi, Daly City, Calif., assignor, by mes x1e assignments, to Baldwin-Lima-Hamilton Corporation, Philadelphia, Pa., a corporation of Pennsylvama Application August 19, 1954, Serial No. 450,928

3 Claims. (Cl. 121-164) My invention relates to pumping jacks for use primarily in operating the sucker rod or polish rod of a pump located at or near the bottom of a well, such as an oil well. An apparatus comparable to the present is shown in the copending application of Ray Bacchi, entitled Pumping Jack, Serial No. 355,102, filed May 14, 1953, and now Patent No. 2,702,025, and assigned to the assignee of the present application.

Pumping jacks are sometimes utilized on wells which are somewhat marginal. These wells are economical to pump when the price of oil is relatively high and the difficulty of operating the pumping mechanism is not too great. Under unfavorable conditions, these wells are necessarily shut down because operation of the pumping mechanism is not justified. There is, consequently, a demand in the industry for a pumping jack which is relatively low in first cost, can operate quite economically, can be moved from one well to another and can effectually pump for a long time without requiring a large amount of mechanism.

It is therefore an object of my invention to provide a hydromechanical pumping jack which meets the requirements above stated.

Another object of my invention is to provide a hydromechanical pumping jack in which the portions of the unit under pressure are relatively few in number and are closely interconnected.

A still further object of my invention is to provide a hydromechanical pumping jack obviating the use of a sizeable pressure vessel.

Another object of my invention is to provide a hydromechanical pumping jack which has a self-contained lubricating system.

Another object of my invention is to provide a hydromechanical pumping jack which can be manufactured of a shape and size to replace the customary mechanical beam pumpers.

A still further object of my invention is to provide a hydromechanical pumping jack which is an improvement over other jacks available commercially.

Other objects, together with the foregoing, are attained in the embodiment of my invention described in the accompanying description and illustrated in the accompanying drawings, in which:

Figure 1 is a side elevation of a hydromechanical pumping jack constructed in accordance with my invention and shown in installed position at a Well being pumped.

Figure 2 is a cross seection, to a dilferent scale, of part of the structure shown in Figure 1, the plane of section being indicated by the line 2-2 of Figure 1.

Figure 3 is a cross section, to an enlarged scale, of the expansible chamber or cylinder and piston portion of my hydromechanical pumping jack, the plane of cross section being longitudinal and diametrical.

Figure 4 is a detailed cross section, to an enlarged scale, the plane of section being indicated by the line 44 of Figure 3.

Figure 5 is a diagrammatic showing of the principal nited States Patent F ice Patented July 24, 1956 mechanical parts and the connecting hydraulic circuit members involved in the operation of the jack on an upstroke.

Figure 6 is a view comparable to Figure 5, but showing the parts of the jack and the hydraulic mechanisms in position for a downstroke of the jack.

While the hydromechanical pumping jack of my invention can readily be incorporated in various and sundry different embodiments, it has successfully been practically embodied as illustrated herein. In this arrangement, the hydromechanical pumping jack is disposed on the ground 6 for operation in connection with a well 7 having a pump (not shown) near the bottom thereof, the pump being connected by a sucker rod or polish rod 8 extending above the ground to a connector 9 of a standard sort.

Located at a convenient spot adjacent the well '7 is a frame 11 preferably fabricated of structural shapes, and including skids, designed for use on the surface of the ground or to be lifted from the ground and transported to any one of various locations. The frame 11 not only includes bottom horizontal skid members but likewise includes a pair of upright members 12 joined to the bottom members and braced by diagonal struts 13. Adjacent the top of the upright members 12 of the frame 11 is a fulcrum 14, including a suitable anti-friction bearing forming a mounting for a beam 16. This is a-suitable structural member of approximately standard construction, for the most part, and is comparable in some respects to the beam normally utilized in mechanical beam pumpers.

At one end, the beam 16 is provided with an appropriate counterweight 17 in the requisite amount for the particular well to which the unit happens to be connected, and at the other end is provided with an arcuate guide frame 18, or horse head, of the kind usually provided. This includes a saddle 19 from the reception of a loop of a cable 21, at its ends connected to the fitting or connector 9. With this arrangement, as the beam 16 is rocked or oscillated on the bearing fulcrum 14, the cable 21 translates the arcuate movement of one end of the beam into a straight line motion to provide suitable travel of the polish rod 8. At the same time, the counterweight 17 overcomes or counterbalances part only of the weight of the structure connected to the fitting 9 to assist in smoothing out the cyclic power required for the' reciprocating operation.

In accordance with my invention, means of a hydraulic nature are provided for reciprocating or rocking the beam 16. This mechanism includes an expansible chamber 26, including a cylinder 27 at one end connected by a pivot bearing 28 to the framework 12. The mechanism also includes a piston 29 disposed at one end of a piston rod 31 projecting from the cylinder and connected by a pivot bearing 32 to an extension 33 forming part of the structure of the beam 16. Hydraulic fluid, such as oil, from a reservoir 34 on the frame 11 is periodically discharged under pressure into the expansible chamber 26 and is released therefrom to the reservoir under the control of a valve mechanism 36 appropriately mounted on the frame and actuated in accordance with the rocking or oscillation of the beam 16.

The hydraulic apparatus is driven by any suitable source of motive power, such as an internal combustion engine (not shown), or an electric motor 37 conveniently mounted on the frame 11 and connected by a belt drive 38 to an economical and eflicient hydraulic pump 39 or" any suitable sort. The pump 39 withdraws hydraulic fluid from the reservoir 34 through an inlet pipe 41 and discharges the hydraulic fluid under a higher pressure into a conduit 42. This conduit extends eventually to the cylinder 26 but is provided with a number of branch paths and controlling instrumentalities.

Considering that the structure is on an upstroke cycle,

the parts are as shown in Figure 5. The fluid discharged from the pump 39 and passing through the conduit 42 enters into a pump unloading valve 43. This valve has a central bore 44 within which a valve spool 46 is operable under the influence of an adjustable spring 47 disposed at one end and under the influence of pressure exerted on the other end of the spool 46. When the spring 47 exerts the major force, the spool 46 is in the position shown in Figure and flow from the conduit 42 is then completely through the pump unloading valve 43 into a duct 48 in which a check valve 49 is situated. From that point, a part of the flow is then through a cylinder unloading valve 51, similar in construction to the valve 43, and having a longitudinal bore 52 within which a valve spool 53 is reciprocable under the influence of an adjustable spring 54. Opposing the spring influence is pressure exerted against the end of the spool 53.

In the condition of the apparatus shown in Figure 5, the spool 53 permits flow from the conduit 4 into a duct 56 which is provided with a flexible hose 57 extending to a port 58 at the lower end of the cylinder 26 and leading into the interior thereof below the piston 29. The piston 29 is provided with a suitable packing 59 so as to be substantially leak proof. Under those circumstances, oil entering under pressure beneath the piston is efiective to drive the piston and piston rod 31 outwardly in the cylinder and to expand the chamber. This motion then rocks the beam 16 in a counterclockwise direction in Figures 1, 5 and 6.

Adjacent the end of the counterclockwise oscillation, an adjustable lug 61, slidable into a selected position on an arcuate extension 60 of the beam 16, abuts and works against a depending actuating lever 62 on a valve core 63. This is rotatable within a valve housing 64 forming part of the valve 36. This valve is conveniently mounted on a structural shape 66 upstanding from and forming part of the frame upright 12. The valve is thus mounted in position just above the beam 16. The effect of the lug 61 is to rotate the valve core 63 from the position shown in Figure 5 into the position illustrated in Figure 6. Prior to the valve reversal with the parts in the position of Figure 5, some of the hydraulic fluid under pressure is diverted from a point in the conduit 48, between the check valve 49 and the valve 51, into a pipe 65 leading into a duct 67 supplied with an appropriate pressure gauge 68 and communicating through a spring pressed check valve 69 with a line 71. Connected into the line 71 by a branch 72 is an accumulator chamber 75 effective to enlarge the capacity of the line 71 in an elastic fashion so that pressure can be maintained in the line 71 despite substantial volume variation. The line 71 continues until it joins a port 70 in the housing 64 of the valve 36. When this port is blocked, as shown in Figure 5, a steady pressure is maintained in the line 71.

When the valve core 63 is rotated from its Figure 5 position to its Figure 6 position, then the pressure within the line 71 is effective to produce flow from the port 70 through a central bore 73 in the valve core 63 and then into a line 74 extending through a metering or needle valve 76 into a conduit 77. A branch 78 extends to the lower end of the pump unloading valve 51. The resulting pressure in the branch 78 causes a prompt shifting of the valve spool 53 from the position shown in Figure 5 into the position shown in Figure 6. This compresses the spring 54 and permits back flow from the conduit 56 through the body of the unloading valve 51 into a line 79 leading through a manual valve 81 into the oil reservoir 34. This fluid path permits the weight of the equipment transmitted to the beam 16 by the cable 21 (which largely overbalances the counterweight 17) to contract, the expansible chamber 26. The piston 29 is thus drivendownwardly within the cylinder 28 so that previously pumped fluid is discharged into the reservoir 34. During this time, any leakage oil which may have passed the spool 53 in the valve 51 into the chamber surrounding the spring 54 is permitted to discharge through a shunt line 82 leading into the chamber from which the line 79 extends back to the reservoir so that the spring chamber of the valve 51 is maintained at a sufliciently low pressure for proper operation.

At the same time that pressure within the lines 77 and 78 is effective to lift the spool 53, it is also transmitted through a check valve 83 into a line 84. The line 84 extends through a branch 86 to the pump unloading valve 43 beneath the spool 46. The pressure transmitted is immediately effective to lift the spool. Despite the lifting of the spools 46 and 53, the accumulator 75 maintains pressure in the lines 71 and 74 and their connections. Lifting of the spool 46 affords access from the pump discharge conduit 42 into a discharge line 87 leading directly into the reservoir 34. Thus, when the reversing valve 36 is actuated by the lug 61, the pump 39 is unloaded and discharges directly into the reservoir 34 at the same time that the expansible chamber 26 is unloaded and itself discharges directly into the reservoir 34. The weight on the expansible chamber drives it into its lowermost extreme position with the beam 16 similarly oscillating clockwise. During this time, the electrical load to drive the pump is diminished since the pump need discharge only back to the reservoir and not against a substantial pressure.

As the beam 16 then rotates clockwise in its oscillation, it eventually comes to a point where an adjustable lug 88, slightly staggered in axial position with respect to the lug 61, moves to abut a staggered lever 89 and to move that lever from the position shown in Figure 6 back into the position shown in Figure 5. This produces a rotation of the core 63 of the valve 36 from its Figure 6 position into its Figure 5 position. The line 71, through which the accumulator 75 has been partially depleted, is blocked so that the accumulator and the line 71 can again be re-charged.

When the valve 63 is moved back from its Figure 6' to its Figure 5 position, the cross passageway 73 connects to a much lower pressure so that the pressure within the line 74 drops. Flow into the line 74 is then through the restricting valve 76, permitting drainage of the cylinder unloading valve 51 at a regulated rate under the influence. of the spring 54 so that the spool 53 changes its position from the Figure 6 location to the Figure 5 location. The drop in pressure in the line 74 also permits drainage of the pump unloading valve 43 under the influence of the spring 46. The rate at which the pump unloading valve spool 76 shifts is controlled by an orifice 92 in a shunt circuit 93 around the check valve 83 which is closed under these circumstances. The effect of the return of the valve spools 53 and 46 to the lower positions, as shown in Figure 5, is again to connect the pump outlet through the conduit 42 to the bottom cylinder port 58 so that the lifting cycle repeats.

During the time that the pump 39 is actively pumping, its maximum pressure is exerted on a pressure regulating valve 94 having a spool 96 therein urged into one position by an adjustable spring 97. Pressure from the conduit 42 at the pump outlet is carried by a line 98 into the interior of the valve body where it is exerted beneath the spool 96. As long as the pressure is below the set amount there is no flow from the regulator valve but when the pressure exceeds the desired value the spool 96 is lifted against the urgency of the spring 97 and uncovers a discharge port 101 leading into a line 102 joined to the line 84. Flow under high pressure into the line 84 is largely blocked by the check valve 83 and the orifice 92, but some flow continues through the branch line 86 so that the high pressure lifts the spool 46 of the pump unloader valve 43. In the lifted position of the pump spool, as shown in Figure 6, discharge from the pump is from the conduit 42 into the line 87 and so back to the reservoir 34. In this fashion, excessive pressure from the pump is not discharged into the cylinder structure 26, but, rather is relieved to the reservoir 34.

Any leakage liquid which passes the spool 96 into the chamber of the spring 97 of the relief valve 1s carried out by a conduit 103 into the spring chamber of the pump unloading valve 43. Drainage from there is through a shunt line 104 extending to connect into the discharge line 87.

In the event the operation of the jack is interrupted while it is on the downstroke, the beam will come all the way down by gravity and remain in its lowermost position. If, however, the unit is stopped at some pomt in the upstroke, the beam will then hold 1ts position. If it is then desired to lower the beam, a normally closed valve 105 is opened to permit the load on the beam to move the piston 29 into its lowermost position, the Oil in the line 57 flowing through the lines 56 and 65 and through the valve 105 into a discharge line 106 extendlng to the reservoir 34.

When the valve 36 reverses into the Figure 5 position, not only is the pressure in the line 74 dropped, but 1n leaving registry with the port 72, the cross passageway 73 aligns with a port 109 connected to a pipe 111. Instead of extending directly to the reservoir 34, the line is utilized as a means for diverting part of the hydraulic actuating fluid to serve as a lubricant for the major moving parts of the structure. For that reason, the pipe 111 and other parts of the lubrication circuits are shown in broken lines to distinguish them from the jack actuating fluid lines.

Flow from the port 109 through the pipe 111 goes to a reservoir 112 built into the framework, as shown in Figures 2 and 5. At an appropriate level in the reservoir 112, there is provided an overflow 113 connected by a pipe 114 to a drain line 116 extending back to the reservoir 34. An atmospheric opening is provided at the upper end of the drain line and is guarded by an air filter 117. With this arrangement, a predetermined level of lubricating oil is maintained in the reservoir 112 at a SllfllClBIllI elevation in the structure to serve as a source of gravity feed of lubricant. From the reservoir, a flexible line 118 extends downwardly into one end 119 of the fulcrum bearing 14 of the beam 16. The fulcrum bearing 14 is interiorly provided with a number of lubricating passageways 121, leading eventually to a discharge opening 122. From this opening, a lead 123 conducts surplus oil not needed for the lubrication of the fulcrum bearing into one end 124 of the upper pivot bearing joining the piston rod 31 to the beam extension 33. Oil flow is into a central passage 125 in this bearing, with adequate lubrication being thus provided. Surplus lubricant leaves the bearing 32 through a passageway 126 and flows into the interior of the hollow piston rod 31.

Also communicating with the interior of the hollow piston rod by means of a passageway 127 is the volume enclosed by a flexible protecting boot 128, at one end secured to the piston rod structure and at the other end secured to the cylinder structure. Variations in interior volume of the boot as the chamber operates do not cause any substantial fluctuation in pressure since flow through the passage 127 to the interior permits equalization. Furthermore, this surging flow also carries some oil vapor and lubricant to the exterior of the piston rod or permits the return to the interior of the piston rod of any surplus of lubricating oil within the boot 128.

Surplus oil from within the hollow piston rod 31 travels through apertures 129 in the lower end thereof into the volume within the cylinder 27 about the piston 29. During the reciprocation of the piston, this oil is carried up to the upper end of the cylinder and, if an excessive amount is present, there is a ready overflow provided on the high side of the piston through a passageway 131 leading into a substantial pipe 132, directed back to the reservoir 34. An

atmospheric vent 136 on the pipe 132 is protected by a filter 137. Oil in a small amount is discharged from the cylinder 27 above the low side of the piston 29 through a line 138 into one end 139 of the lower pivot bearing interposed between the lower end of the cylinder and the framework. This bearing is of a typical construction utilized not only for the fulcrum bearing, but also for the upper pivot bearing 32.

The bearing 28 (Figure 4) comprises, preferably, a central pin 141 keyed into supporting blocks 142 and 143, secured by bolts 144 to the adjacent structure. The pin itself is held in position by take-up nuts 146 and 147. The pin is further provided with an axial bore 148 through which the lubricant travels into branch passages 149, 151 and 152. These, in turn, lead onto lubricating grooves 153 in an anti-friction bushing 154 pressed into the boss 156 of the supporting block 157 of the bearing 28. Lubricant seals 158 are utilized at opposite ends of the bearing bushing 154 and thrust washers 159 are disposed between the blocks 142 and 143 and the boss 156. The bushing 154 is surrounded by a groove 161 opening into a port 162 provided with a drain line 163 leading back to the reservoir 34. Oil which drains from the lubricant reservoir 112 and which has passed through the fulcrum bearing 14, the upper pivot bearing 32, the interior of the cylinder 27, and the lower pivot bearing 28, is finally returned to the reservoir 34. With this lubricating circuit, there is provided a means for automatically lubricating under gravity pressure all of the moving parts of the structure subjected to any substantial load.

There has thus been provided, in accordance with the invention, a hydromechanical pumping jack of a simple straightforward construction, useful on any one of a number of Well pumps, self-contained, capable of ready regulation and operation under variant conditions, and incorporating not only its own automatic hydraulic actuating structure but also a built in gravity pressure lubri' eating system for the heavily loaded bearings.

What is claimed is:

1. A hydromechanical pumping jack comprising a frame, a beam, a fulcrum for said beam on said frame, means at one end of said beam for connection to a pump rod, a counterweight at the other end of said beam, an expansible hydraulic chamber, means connecting said chamber to said frame and to said beam, a source of hydraulic fluid under pressure, a conduit interconnecting said source and said chamber, a valve actuated by said beam for controlling fiow in said conduit, a reservoir high on said frame, means for diverting hydraulic fluid from said valve to said reservoir, means for conducing hydraulic fluid from said reservoir down to said fulcrum bearing, and means for conducting hydraulic fluid from said fulcrum bearing to said source.

2. A hydromechanical pumping jack comprising a frame, a beam, a fulcrum bearing for said beam on said frame, means at one end of said beam for connection to a pump rod, a conterweight at the other end of said beam, an expensible hydraulic chamber, bearing means pivoting said chamber at one end to said frame and at the other end to said beam, a source of hydraulic fluid under pressure, a conduit interconnecting said source and said chamber, a valve in said conduit, means responsive to the motion of said beam relative to said frame for periodically actuating said valve, lubricating pipes connected to said fulcrum bearing and to said bearing means in series, a reservoir on said frame means for periodically diverting hydraulic fluid from said conduit to said reservoir, and means for conducting hydraulic fluid from said reservoir to said fulcrum bearing and from said bearing means to said source.

3. A hydromechanical pumping jack comprising a frame, a beam, a fulcrum for said beam on said frame, means at one end of said beam for connection to a pump rod, a counterweight at the other end of said beam, a hydraulic cylinder, means pivoting said cylinder to said frame, a piston and piston rod reciprocable in said cylinder, means pivoting said piston rod to said beam, a source on said frame of hydraulic fluid under pressure, a conduit interconnecting said source and said cylinder, a valve in said conduit and mounted on said frame above said fulcrum, valve levers depending toward said fulcrum, and lugs upstanding on said beam adjacent said fulcrum for engaging and actuating said valve levers as said beam moves relative to said frame.

References Cited in the file of this patent UNITED STATES PATENTS Lower Oct. 29, 1935 Salentine Mar. 16, 1937 Vernon et a1 Nov.15, 1938 Bays Dec. 27, 1938 Eckert May 14, 1940 Perry Feb. 10, 1942 Barksdale July 26, 1949

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