US2780063A - Counterbalanced pumping jack - Google Patents

Description

Feb. 5, 1957 R. BACCHI COUNTERBALANCED PUMPING JACK 3 Sheets-Sheet 1 Filed Oct. 27, 1955 INVENTOR. Fay flaw/n BY FEE. 5, 1957 R. BAccHI COUNTERBALANCED PUMPING JACK 3 Sheets-Sheet 2 Filed 001. 27, 1955 VINVENTORL P0] 5065/7/ BY MWMZJ Array/WK;

Feb 5, 1%? R. BACCHI fi fl COUNTERBALANCED PUMPING JACK Filed Oct. 27, 1955 3 Sheets-Sheet 3 KZWr 0M United States Patent COUNTERBALANCED PUMPING JACK Ray Bacchi, Daly City, Calif., assignor, by mesne assignments, to Baldwin-Lima-Hamilton Corporation, Philadelphia, Pa., a corporation of Pennsylvania Application October 27, 1955, Serial No. 543,088

1 Claim. (Cl. 60-51) My invention relates to means for mechanically operating deep well pumps, usually oil pumps, and is of the general sort shown in my co-pending application entitled Hydraulic Pumping Jack, Serial No. 529,241, filed August 18, 1955, and assigned to the assignee of this application. Pumping jacks are utilized under widely variant circumstances and on diflerent types of wells of varying depth and pumping speeds. It is often necessary to provide a relatively simple and economical pumping jack for wells which are not particularly productive and which are often pumped by means of the well-known beam pumpers, usually mechanically driven.

It is an object of my invention to provide a pumping jack which can readily be substituted for a beam pumper with improved results.

Another object of my invention is to provide a pumping jack in which the counterbalancing mechanism normally provided with a beam is dispensed with.

Another object of my invention is to provide a counterbalanced pumping jack to compact construction.

Another object of my invention is to provide a pumping jack having a number of improved features.

Another object of my invention is, in general, to provide an improved counterbalanced pumping jack.

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 counterbalanced pumping jack constructed in accordance with my invention and in position on a well.

Figure 2 is a diagrammatic showing of my counterbalanced pumping jack, the hydraulic circuits being indicated by single lines and some of the structure being diagrammatically illustrated in cross section.

Figure 3 is a cross section through the jack mechanism, parts of the structure being broken away to reduce the size of the figure.

Figure 4 is a cross section showing the interior construction of a make up pump utilized in connection with the pumping jack.

While the subject matter of the invention can be incorporated in a large number of variant forms depending particularly upon the requirements of the environment in which it is to be operated, it has successfully been embodied in practice as generally illustrated herein.

In this instance, the counterbalanced pumping jack is utilized in connection with a well 6 from which a polish or sucker rod 7 projects to a fitting S. This joins an actuating cable 9 secured to the horse head 11 of a pumping beam 12. This beam is like the customary beam in that it is provided with a pin connection 13 to a support 14 included in and suitably mounted on and secured to a skid base 15 and adequately braced by struts 16. The pumping beam is not like the customary arrangement in that it terminates substantially at the rocker mounting 13 and does not extend to provide a counterbalance and does not carry any counterbalance weights. In fact, the

2,780,063 Patented Feb. 5, 1957 pumping beam 12 distinguishes from the usual arrangement in that it is not itself counterbalanced.

In accordance with the invention, there is provided a means on the skid 15 for actuating the pumping beam 12. This constitutes a jack mechanism generally designated 17 at its upper end connected by a pivot connection 18 to a mounting pad 19 on the pumping beam 12 and on its lower end having a rocker connection 21 to the skid 15. The jack mechanism 17 is included in hydraulic circuits and derives its power from aninternal combustion engine 22 or similar power source likewise mounted on the skid 15 and connected by driving belts 23 with some of the hydraulic structure 24.

Much of the oil for use in the hydraulic system is normally contained in a sump tank 26 situated at a low point on the skid 15 and provided with a filler and atmospheric vent 27 so that the sump tank 26 is normally partially filled with oil up to a level 23 and above that level contains air under atmospheric pressure at all times. Extending into the oil in the sump tank 26 is an inlet pipe 39 of an oil pump 31 appropriately driven by the belt 23. Conveniently, the pump is mounted with much of the attendant structure on the sump tank 26 which serves also as a frame.

The pump 31 discharges through a pipe 32 having a check valve 33 therein into a pressure relief valve 34. Within the valve 34 is a guided piston .36 urged in one direction by a spring 37 positioned by an adjuster 38 so that when the pressure of the pump is below a predetermined valne, the output of the pump passes through a line 39 to a main valve 41. When the pump pressure is excessive, the piston 36 rises against the influence of the spring 37 and uncovers a port leading into a line 42 extending back to the sump tank 26. Under such circumstances the excessive amount of fluid simply returns to the sump tank for recirculation.

Oil flowing from the line 39 into the main valve 41 travels in either of two paths depending upon the particular position of the shuttle 43 of the main valve. This has two extreme positions, a right-hand position as illustrated in Figure 2, and an opposite left-hand position. in the righthand position shown, the incoming oil from the line 39 is transferred between lands 44 and 46 into a pipe 47 leading to a duct 48 in the jack mechanism 17. The duct 48 is formed in a lower head 49 serving as a mounting for a central tube 51 secured in position by a nut 52. Apertures 53 establish communication between the interior of the tube 51 and the duct 48, the bottom of the central tube being otherwise sealed. The central tube 51 extends axially upward in the jack mechanism 17 and terminates in a tube head 54 which carries adequate packing devices 56.

Reciprocable around and relative to the central tube 51 is a piston tube 57 secured on an upper head 58 forming part of the pivot connection 18 and included in the jack mechanism 17. Thus, when pressure fluid enters the duct 48 it travels upwardly through the interior of the central tube 51 into a central volume 59 Within the piston tube 57 and exerts an expanding force. This force is effective to lift the pumping beam 12 upwardly.

Because of volumetric capacity requirements, the piston tube 5 7 carries with it a coaxial sleeve 61 similarly secured to the upper head 58 being also fastened to a piston 62 at its lower end. The piston 62 is provided with adequate packing 63 and is reciprocable within a cylinder 64 forming part of the jack mechanism 17.. As the piston 62 rises with the rise of the head 58, the interior volume between the piston and an upper cylinder closure 66 is reduced. Consequently, the hydraulic content of the an.- nular cylinder chamber 67 is driven out through a port 68 into a pipe 69. This leads back to the main valve 41. In the position of the valve shuttle illustrated, the return oil from the pipe 69 is transferred between lands 44 and 71 into a pipe 72 leading to a conduit 73 extending into the sump tank 26. Thus, as the upper head 58 rises by pressure within the central volume 59, the content of the annular chamber 67 is expelled into the sump tank 26.

'In accordance with my invention, and pursuant to the arrangement of the structure, there is provided a means for assisting in the lifting of the pumping beam 12 as described, such assisting means being adequate substantially to counterbalance part of the weight or load on the connection 9. Thus the weight of the pumping mechanism in the well-is partially offset and the duty of the pumping jack is then substantially equalized to drive the structure upwardly n the upstroke and downwardly on the downstroke. For this reason, the lower head 49 to which the cylinder 64 is attached is formed beneath the piston 62 with a chamber 75. This is joined by a duct 76 leading through apipe 77 having a hand valve '78 therein to the bottom ofabalance tank 7 9.

The balance tank is of the sort shown in my companion application and contains a lower body 81 of oil under pressure and an upper body 82 of air under pressure, this pressure being substantially sufficient to balance the weight on the cable 9. Thus, the pressure exerted through the pipe 77 when the hand valve 78 is open, as it normally is, and acting through the duct 76 and within the chamber 75 on the lower face of the piston 62 is just sufficient to counterbalance the reciprocating parts. As the mechanism reciprocates on the upstroke, there is a surge of oil from the balance tank 79 into the jack mechanism 17'and on the downstroke there is a return surge of the balancing oil from the jack mechanism 17 back to the balance tank 79. The jack mechanism can be locked or'held in place in any particular position for service op erations by closing the hand valve 78.

When the mechanism arrives at the upper part of the stroke of the balancing beam 12, a mechanism is effective to reverse the operation. The balancing beam 12 carries a sector 83 having adjustable, axially spaced lugs 84 and 86 thereon. In the paths of the individual lugs are two, axially spaced depending arms 87 and 88 on the rotatable body 89 of a pilot valve 91 having a stationary housing 92. During the upstroke and in the illustrated position of the pilot valve, pressure fluid from the line 32 flows through a pipe 93 into a passage 94 in the pilot valve. From such passage flow is into a line 96 having a regulating device 97 therein. The regulating device includes a check valve 98 open under pressure from'the direction of the pilot valve and includes a shunt orifice 99. Flow through the remaining part of the pipe 96 is into a chamber 101 in the main valve 41 within which the land 71 reciprocates as a piston. The pressure against the land 71 or piston urges it into the right-hand position as shown in the figure.

During this time, a corresponding land 102 or piston in the other end of the main valve 41 reciprocable in a chamber 103 therein is also at the right-hand end of its stroke. The chamber 103 is in communication with a pipe 104 having a regulating mechanism 106 therein. This regulating mechanism incorporates a check valve 107 which closes when the direction of flow is from the chamber 103 into the pipe 104 and incorporates a shunt orifice 108 regulating the speed of flow in that direction. The pipe 104 connects to the housing 92 of the pilot valve and flows through a passage 111 in the body 89 to a pipe 112. This returns to the sump tank 26 and operates substantially at atmospheric pressure.

connects the pipe 93 through the channel 94 with the pipe 104and connects the pipe 96 through thepassage 111 with the pipe'-112.-- Thus, pressure fluid travels ,into the pipe 104 freely, opening the check valve 107 and flowing immediately into the chamber 103 wherein it exerts i ts influence against the piston 102.

Since the pipe 96 is connected to the pipe 112, the pressure in the chamber 101 drops substantially to atmospheric so that the shuttle 43 is translated from its extreme right-hand position to its extreme left-hand position. The contents of the cylinder 101 are expelled through the pipe 96 but since the check valve 98 then immediately closes the return flow is only through the shunt orifice 99 so that the speed of shifting of the shuttle 43 is regulated. Oil passing through the pipe 96 then travels through the passage 111 into the pipe 112 and so returns to the sump 26. Thus, the stroke is reversed by the reversal of the main valve 41. Under these conditions, flow from the pump 31 through the pipe 39 is then not into pipe 47 but rather is into the pipe 69 and through the duct 68 into the annular cylinder chamber 67 to exert a downward force on the jack piston structure.

Similarly, the central volume 59 is connected through the duct 48 and the pipe 47 not with the pipe 39, as before, but rather with the return pipe 73 leading to the sump. The oil discharged as the piston 62 is forced down is expelled from the central volume 59 into the sump 26. At the bottom of the stroke, a reversal takes place since the lug 86 contacts the then centrally positioned lever 88 and rocks the pilot valvebody 89 back into the position illustrated in Figure 2, the structure then assuming its pictured position. The reversal of the shuttle 43 is regulated in speed by the rate of return flow from the pipe 104 through the restricting orifice 108 into the pipe 112 leading to the sump tank. Thus, the pumping jack reverses itself at the opposite ends of the stroke, being balanced throughout each stroke by the surge flow between the chamber and the balance tank 79 through the pipe 77.

Certain auxiliary structures are utilized to maintain this structure in continued opera-tion. Inevitably some leakage takes place in the fluid system not only of oil but also of air and consequently make-up mechanism is provided.

At a convenient location there is disposed a make-up pump 121 (Figure 4) having a central cylinder 122 within which a main piston 123 is reciprocable. The cylinder at one end is connected by a pipe 124 to the pipe 69 which has within it a pressure fluctuating in accordance with the position of the main valve spindle 43. At the other end of the cylinder on the other side of the piston 123, a pipe 126 connects to the pipe 47. This has a simultaneous but opposite fluctuation in pressure since it is likewise connected into the body of the main valve 41. Thus, the piston 123 is subjected to alternating pressures on opposite sides in time with the reciprocation of the jack mechanism 17.

The piston 123 is joined to a large plunger 127 reciprocable within a cylinder 128 having an inlet check valve 129 therein. This controls flow in one direction from a pipe131 extending into the air space within the sump tank 26 above the oil therein and drawing air through the atmospheric vent 27. The cylinder 128 is likewise provided with an outlet check valve 132 connected to a pipe 133 leading to a junction 134 with the air space 82 of the balance tank 79. As the piston 123 reciprocates, the plunger 127 also reciprocates and when it is withdrawn induces air to flow inthrough the inlet check valve 129 and then compresses such air and expels it through the check valve 132 and the line 133 into the balance tank.

While the air pump plunger 127 continually operates and furnishes air to the balance tank, the pressure is kept at a predetermined value as any excess is blown off through a relief valve 136, carried in a line 137 having a junction 138 to the balance tank. The relief valve 136 has a spring pressed valve plunger 139 therein with an adjustment 141 for setting itsvalue. When the pressure .within the balance tank 79 is low, the valve 139 covers the outlet port 142 of the relief valve. When the pressure rises sufiiciently, the plunger 139 is lifted against the urgency of the spring and excess air discharges through a pipe 143 extending from the port 142 to the pipe 112 and so returns to the sump from which it escapes through the atmospheric opening 27. There is thus maintained at all times a set air pressure within the balance tank.

The piston 123 also serves to actuate an oil make-up pump. Secured to the piston 123 is a plunger 146 reciprocable Within a cylinder 147 connected by suitable passages 148 and 149 to an inlet duct 151 having a check valve 152 therein and extending into the sump tank 26 below the oil level. The passage 148 is also connected to a pipe 153 having a check valve 154 therein and leading into a fitting 156 in the balance tank 79 preferably below the oil level. As the piston 123 reciprocates, the plunger 146 is reciprocated in time with the operation of the pumping jack mechanism 17 so that oil is induced to flow from the sump tank into the oil make-up pump and is expelled therefrom through the pipe 153 into the balance tank 79.

Since the fitting 138 and the relief valve 136 are sit uated at a predetermined level or elevation in the side of the balance tank, the oil supplied to that tank rises to the same predetermined level 157. Oil rising above the level 157 is discharged, when the pressure is great enough, by overcoming the relief valve 136 and flowing out through the pipe 143 into the pipe 112 which returns it to the sump tank 26. There are thus provided make-up pumps for oil and for air so that the balance tank 79 is at all times adequately supplied.

Sometimes, for initially filling the balance tank before substantial pressure is imposed thereon, there is provided a shunt line 158 having a hand valve 159 therein and extending from the pressure line 93 to a fitting 161 in the balance tank. With this arrangement, when the hand valve 159 is open and the pump 31 is running, oil under some pressure not exceeding the pressure at which the relief valve 36 is set can be transferred through the pipe 158 and the fitting 161 into the balance tank. When a sufiicient supply is had to assure continuous operation of the pumping jack, the valve 159 is closed and the makeup pump plunger 146 is relied upon for replenishing the balance tank thereafter.

With this arrangement, the pumping jack mechanism carries within its reciprocating member an expansible chamber always in communication with the balance tank so that the balance tank serves to ofilset the continuous load on the pumping connection 9. While in some pumping jacks the balance tank is utilized primarily as a reservoir with a relatively small sump tank, in the present instance, the balance tank serves primarily as a counterbalance and the sump tank 26 is enlarged to serve as the principal oil reservoir. With this arrangement, there is afforded a simple, compact, self-contained mechanism applicable to a Well previously mechanically pumped and which is readily counterbalanced to the exact amount required merely by varying the pressure at which the balance tank 79 is operated and this is accomplished through regulation of the relief valve 136.

What is claimed is:

A counterbalanced pumping jack comprising a base, a pumping beam, 9. pin connection between said pumping beam and said base, a jack mechanism including an up right cylinder, a rocker connection between the bottom of said cylinder and said base, a central tube secured to said rocker connection and extending upwardly through said cylinder, a tube head on the upper end of said central tube, a piston tube reciprocably engaging said tube head and extending around said central tube into said cylinder, a piston on the bottom of said piston tube and reciprocably engaging said cylinder, a pivot connection between the top of said piston tube and said pumping beam, a balance tank, means interconnecting said balance tank and said cylinder below said piston, a pump, a sump tank, a main valve, means including said main valve for interconnecting said pump and said sump tank to said central tube, means including said main valve for interconnecting said pump and said sump tank to said cylinder above said piston, and a pilot valve actuated by said pumping beam for controlling said main valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,910,766 Hobson May 23, 1933 2,477,359 Barksdale July 26, 1949 2,564,285 Smith Aug. 14, 1951 2,572,748 Noll et a1. Oct. 23, 1951

Images