US2664764A - Foam pressure balanced walking beam type oil well pumping jack - Google Patents

Description

J 1954 1.. A. BLACKBURN FOAM PRESSURE BALANCED WALKING BEAM TYPE OIL WELL PUMPING JACK Filed Sept. 15, 1951 INVENTOR. LUTHER/1 BLACKBURN A 7TORNEV$ Patented Jan. 5, 1954 UNITED FOAM PRESSURE BALANCED WALKING BEAM TYPE OIL WELL PUMPING JACK Claims. 1

This invention relates to pressure balanced, walking beam type, oil well pumping jacks and more specifically contemplates improvements in the apparatus disclosed in my copending application, S. N. 213,387, filed March 1, 1951 for Hydraulic Lift, Walking Beam Type, Pumping Jacks, now abandoned, of which the present application is a continuation-in-part.

Essential structure comprising a part of the present invention and common to the application for patent last above-referred to, includes a walking beam pivotally supported intermediate its ends upon a Sampson post adjacent the well. To one end of the beam, power is applied for vertically swinging a horse-head carried by the opposite end of the beam and connected to the polish rod. The load upon the jack changes with each stroke. On the down stroke of the sucker rod string in the well, the weight of the rods constitutes the chief component of the load, while on the upstroke, the weight of the column of fluid being raised is also carried by the walking beam. It is a general object of the present invention to provide a device of this type characterized by embodiment therein of a pressure-actuated ram operable to oppose gravitation of the rods and fluid in the well throughout the cycle of operation of the device while alternately opposing and supplementing the prime power source.

More specifically, an object hereof is to provide mechanism for producing a foam pressure cushion to counterbalance, within a predetermined range, the weight of the sucker rod string and approximately one-half the weight of the fiuid column in the well.

Another object is the provision of means associated with the ram to produce an oil-containing foam within the ram cylinder so as to assure lubrication of the piston throughout its stroke and assist in preserving an efiective seal between the'piston and cylinder Wall.

Still another object is to provide a counterbalancing normally sealed foam pressure system embodying a pressure reservoir and a ram, operable to exert an upward thrust against the walking beam in opposition to the direction of imposition of the load thereon, providing for a variation in pressure during each stroke of the rod string, with the pressure range being determined primarily by the displacement of the piston relative to the capacity of the pressure reservoir, wherein the pressure increases during the downstroke of the rod string in opposition to the prime mover to retard the reversal of direction of movement of the rods at the bottom of the stroke, relieving 2 the shock upon the rods as they assume the load of the fluid column in the well, and decreases during the upstroke of the rod string while supplementing the prime mover to correspondingly retard the reversal of direction of movement of the rods at the top of the stroke.

Other objects and salient features of my invention include the provision of auxiliary means for lubricating the piston under pressure at the upper end of its stroke, a pressure cylinder closed at opposite ends and having orifices in the wall thereof through which components of the foam are drawn and expelled, and for the provision of bafiles within the pressure reservoir to induce agitation of the foam during successive strokes of the piston.

The above and numerous other objects will be apparent from an examination of the following description read in the light of the accompanying drawings, in which:

Fig. 1 is a perspective view of embodying my invention.

Fig. 2 is a longitudinal section through the unit, illustrating particularly the pressure ram and reservoir assembly.

Fig. 3 is a sectional view, taken on line 33 of Fig. 2.

Fig. 4 is an enlarged broken sectional view through the ram cylinder depicting particularly the construction of the piston.

Fig. 5 is an elevation of the closure assembly for the upper end of the cylinder, omitting the sliding plate carried by the piston rod.

Referring to the drawings in detail, the numerals of which indicate similar parts throughout the several views, l0 designates generally the foundation of the unit comprising spaced, parallel H-beams H and transverse beams [2. A pedestal I3, mounted upon H-beams i4, carried by the foundation It, supports a vertically disposed tank 15, comprising a pressure reservoir. The tank l5 serves the additional function of a Sampson post, having mounted on its upper end a bearing I6 for a pivot pin ll upon which the walking beam [8 is fulcrumed. An engine IQ for actuating the walking beam [8, is mounted upon the rearward end of the foundation It, the power being transmitted through suitable reduction gearing enclosed in a case 20, so as to rotate a shaft 2| projecting from opposite sides of the gear case. Crank arms 22, secured to the ends of the shaft 2|, carry crank pins 23, upon which are pivoted the lower ends of actuating links 24. The upper ends of the a pump jack links 24 are secured to a transverse shaft 25 Characteristic condition of the foam, I provide a pair of perforated bafiies 58 and 59 within the bore of reservoir 36, through and between which bafiles the laterally moving foam is compelled to pass.

The foam pressure maintained within the tank is determined by a regulator Bil connected to the cylinder 33 by a tube 6| The regulator 69 which controls the operation of the compressor 56 in an obvious manner, is adjusted, with the piston 31 equi-spaced from the ends of its stroke, to actuate the compressor whenever the foam pressure falls below an amount required to counterbalance the weight of the rod string plus one half the weight of the fluid column raised by the rods during the upstroke of the latter. A generator 62 (Fig. 1), actuated by the engine 19, provides power for the motors 52 and 57. Liquid from the tank 53 may be supplied to the tank [5 during operation of the uni-t by opening the valves 54, which permits its gravitation into the reservoir 3%.

The operation of my invention is further briefly described as follows: After filling the reservoir 36 to the level indicated in Fig. 2 and with the walking beam tilted to a position intermediate the ends of its stroke so as to place the piston 31 in a position approximately equi-spaced from the ends of its stroke the compressor 55 is energized to force air into the reservoir 33 and tank K it. The forcible expulsion of air through the ports of tube 55 into the liquid transforms the latter into foam, filling the tank [5 and cylinder 33. The pressure is preferably raised, as above indicated, until the weight of the sucker rods and one-half of the weight of the fluid in the tubing string is counterbalanced.

As the fluid in the well is carried by the tubing string during the downstroke of the rods, the pressure behind the piston 3! opposing the weight of the rods, is sufficient to maintain the jack inactive. The operation is initiated by starting the engine 19 which supplies sufficient power to overcome the balance of pressure within the ram and by raising the outer end of the walking beam lowers the rod string in the well. Incident to this operation, the piston is correspondingly lowered in the cylinder 33, progressively increasing the pressure within the ram reservoir 35 and tank Id. The increase in pressure is effective to slow the movement of the rod string as the latter approaches the lower end of its stroke, During the initial phase of the upward movement of the rod string, the rods assume the weight of the fluid in the tubing, but as the velocity of their movement is retarded, due to the progressively greater pressure produced in the tank by the piston moving in opposition to the downward movement of the string, the stretching of the rods is gradually accomplished, the stress upon the tool joints is minimized. Reversal of direction of movement of the rods also reverses the direction of movement of the piston, and accordingly the pressure within the tank is exerted against the walking beam in an upward direction, supplementing the action of the engine. Thus at the beginning of the upward movement the velocity of movement of the rod string is accelerated to compensate for the retardation of the movement of the string during the preceding stroke. However, as the piston and the rod string continue their upward movement, the pressure within the tank is progressively dissipated and, accordingly, the velocity of the string is again retarded soasjg effect a slower reversal of direction of movement at the top of the cycle.

It will be observed that, disregarding the variation in pressure of the ram during each cycle of operation, the range of which variation is dependent upon the displacement of the piston relative to the capacity of the tank [5 and reservoir 36, the effective load upon the engine I9 is substantially the same on each stroke, and is generally measured by the power required to raise the rod string and one-half the fluid weight. It will be understood that the compressor 56 is energized in response to actuation of the regulator Ed only when foam pressure within the tank l5, and transmitted to the regulator through the tube 6!, falls below the minimum required. to counterbalance the weight of the rod string plus one-half the weight of the fluid in the Well when the string is intermediate the ends of its stroke.

Any foam or oil leaking past the piston is permitted to drain from the cylinder through a tube 63. The tube 64 from the compressor 56 to the perforated tube 55 is equipped with a check valve 65 and a shut-off valve 66, manually operated, to facilitate control of pressure within the reservoir, cylinder and tank, as will be obvious.

The single embodiment of my invention shown in the drawings hereof and described above, is only illustrative of numerous modifications which may vary from the specific form depicted in number, shape, size, design and proportion of the various parts, and that any such changes that fall within the definitions of the claims appended hereto are included within the scope of the present invention.

What I claim and desire to secure by Letters Patent is:

1. In a foam counterbalanced oil well pumping jack for actuating a sucker rod in a well tubing. string, a Sampson post comprising a foam pres-- sure tank, a walking beam pivoted intermediate: its ends upon said Sampson post, means carried; by said beam to connect the forward end thereof to the sucker rod string, a cylinder disposed with its axis in the Vertical plane of said walking beam, extending obliquely through and sealed to said tank, and having its lower end in open communication with said tank, a piston in said cylinder, a piston rod pivoted to said piston and. extending from the upper end of said cylinder, an arm depending from the forward end of said walking beam and pivoted to said piston rod, power means connected to the rearward end of said walking beam for pivotally reciprocating the latter, means for producing a foam lubricant within said tank, means for maintaining said lubricant under pressure sufficient to counterbalance a weight in excess of the Weight of the sucker rod string and one half the weight of the fluid in the tubing string during the initial stages of the upstroke of said rod string and piston.

2. In a foam counterbalanced oil well pumping jack for actuating a sucker rod in a well tubing string, a Sampson post comprising a foam pressure tank, a walking beam pivoted intermediate its ends upon said Sampson post, means carried by said beam to connect the forward end thereof to the sucker rod string, a cylinder extending through said tank in a vertical plane, obliquely to the vertical axis of said tank, and having its lower end in open communication with said tank, a piston in said cylinder, a piston rod pivoted to said piston and extending from the upper end of said cylinder, an arm depending from the forwardend of said walking beam and pivoted to said piston rod, power me'arm connected to the rearward end of said walking beam for pivotally reciprocating the latter, means for producing a foam lubricant within said tank, means for maintaining said lubricant under pressure sufficientv to counterbalance a weight in excess of the weight of the sucker rod string and one half the weight of the fluid in the tubing string during initial stages of the upstroke of said rod string and piston, said pressure tank and. lower end of said cylinder being sealed whereby the pressure in said tank increases. during the downstroke fo the rod string and piston.

3. In a foam pressure. counterbalanced oil well pumping jack for actuating a sucker rod in a well tubing string, a Sampson post comprising a foam pressure tank, a walking beam pivoted intermediate its ends upon said Sampsonv post, means carried by said beam to connect the forward end thereof to the sucker rod string, a cylinder disposed with its axis in the vertical plane of oscillation of said walking beam, extending obliquely through. said tank, sealed thereto, and having its lower end in open communication with said tank, a piston in said cylinder, a piston rod pivoted to said piston and extending from the upper end of said cylinder,- an arm depending from the forward end of said walking beam and pivoted to said piston rod, power means connected to the rearward end of said walking beam for pivotallyreciprocating the latter, a perforated tube within said tank, a compressor connected to said tube to inject air'unde'r pressure through the perforations of said tube into said tank, a quantity of foam-producing liquid in said tank to fill said tank with foam in response to actuation of said compressor, and means to maintain said foam under sufficient pressure to counterbalance a portion of the load upon said walking beam during the upstroke of said rod string.

4'. In a foam pressure counterbalanced oil well pumping jack for actuating a sucker rodin awell tubing string, a Sampson post comprising a foam pressure tank, a walking beam pivoted intermediate its ends upon said Sampson post, means carried. by said beam to connect the forward end thereof to the sucker rodstring, a cylinder-die posed with its. axis, in the vertical plane of said walking beam, extending obliquely through said tank, sealed thereto, andihaving its lower end in open communication with said tank, a piston in said cylinder, a pistonlro'd pivoted to said piston and extending from the upper end of said cyl; inder, an arm depending rrom the forward end of said walking beam and pivotedto' said piston rod, power means connectedto'the rearward end of said walking beam. for pivotally reciprocating the latter, a perforated tube within said" tank, a compressor connected to said. tube, to inject air under pressure through the perforations of said tubev into, saidtank, a quantity of foam-producing liquid in saidtank to, fill said'tank'with foamin response. tov actuation of said" compressor, andmeans to produce and" maintain said" foam under. minimum pressure sufllcient' to counterbalance aload upon said'beam in excess of'the weight of the rod string.

5. In afoam pressure counterbalanced oilwell pumping jack for actuating a sucker rod in a. well tubing string, a Sampson post" comprising a. foam pressure tank,fa walkingjbeam" pivoted intermediate its endsiu'pon said Sampson post; means c'arriedlby saidgbeanito connect theifor ward end thereof to thesucker rodstring'; a cylinder disposed in the plane of oscillation of said walking beam, extending obliquely through said tank, sealed thereto, supported thereby, and having its lower end in open communication with said tank, a piston in said cylinder, a piston rod pivoted to said piston and extending from the upper end of said cylinder, an arm depending from the forward end of said walking beam and pivoted to said piston rod, power means connected to the rearward end of said walking beam for pivotally reciprocating the latter, a perforated tube within said tank, a compressor connected to said tube to inject air under pressure through the perforations of said tube into said tank, a quantity of foam-producing liquid in said tank to fill said tank with foam in response to actuation of said compressor, and means to maintain said foam under sufiicient pressure to counterbalance a portion of the load upon said walking beam, the pressure in said tank being variable in direct relation to the movement of said piston in said cylinder in response to movement of said beam.

6. In a foam-pressure counterbalanced oil well pumping jack for actuating a sucker rod in a well tubing string, a Sampson post comprising a foam pressure tank, a walking beam pivoted intermediate its ends upon said Sampson post, means carried by said beam to connect the forward end thereof to the sucker rod string, a cylinder disposed in the plane of oscillation of said walking beam, extending obliquely through said tank, sealed thereto, supported thereby, and having its lower end in open communication with said tank, a piston in said cylinder, a piston rod pivoted to said piston and extending from the upper end of said cylinder, an arm depending from the forward end of said'walking beam and pivoted to said piston rod, power means connected to the rearward endof said walking beam for pivotally reciprocating the latter, a perforated tube within said tank, a compressor connected; to said tube toinj e'ct air under pressure through the perforations of said tube into said tank a quantity of foam-producing liquid in said tank to fill said tank with {cam in response to actuationof said compressor, and means to maintain said foam under pressure sufficient to counterbalance a progressively greater proportion of the load during the downstroke of the rod string.

7. In a foam-pressure counterbalanced oil well pumping jack for actuating a sucker rod in a well tubing string, a Sampson post comprising a foam pressure tank, a walking beam pivoted intermediate-its ends'upon said Sampson post,- means carriedby-said beam to connect the forward'end thereof to the sucker rod string, acylinder disposed in the plane of oscillation of said walking beam, extending obliquely through said tank and having-its lower end inopen communication with said tank, apiston in said cylinder, a piston rod pivoted to said piston and extending from the upper end of said cylinder; an arm depending from the forward end of said walking beam and pivoted to said" piston rod, power means con nectedto the rearward end of said walking beam forpivotally recipro'catingthe latter, a perforated tube within said tank, a compressor connected to said tube to inject air under pressure through the perforations of said tube into said tank, a quantity of foam-producing liquid in said tank to fill said tank with foam in response to actuation of said compressor, and means-to-maintain said foam i under" sufficient pressure to counterbalance a portion: of the load uponsaid walking beam 9 during the upstroke of said rod string, and means comprising a regulator to actuate said compressor whenever pressure within said tank falls below a predetermined level.

8. In an oil well pumping jack for actuating a sucker rod string in an oil well tubing string, a foam-balance pressure tank, a cylinder extending obliquely through and sealed to the tank and thereby supported, with the axis of said cylinder intersecting and disposed in the vertical plane of the axis of said tank, means connecting the lower end of the tank to the lower end of said cylinder, a piston in said cylinder, a walking beam pivoted on said tank, an arm depending from the underside of one end of said walking beam, a piston rod pivotally interposed between said piston and the lower end of said arm, power means connected to the other end of said walking beam to pivotally reciprocate the latter upon said tank, said cylinder, tank and said first-named means being sealed whereby the pressure in said tank varies in direct relation to movement of said piston on successive strokes.

9. In an oil well pumping jack for actuating a sucker rod string in a well tubing, a foam-balance pressure tank, a cylinder extending obliquely through and sealed to the tank, with the axis of said cylinder intersecting and disposed in the vertical plane of the axis of said tank, means connecting the lower end of said tank to the lower end of said cylinder, a piston in said cylinder, a walking beam pivoted on said tank, an arm depending from the underside of one end of said walking beam, a piston rod pivotally interposed between said piston and the lower end of said arm, power means connected to the other end of said walking beam to pivotally reciprocate the latter upon said tank, the downward movement of said piston in said cylinder being efiective to raise the pressure in said tank and increase the resistance of said cylinder and piston assembly to upward movement of the end of said walking beam to which said power means is connected so as to retard said movement.

10. In an oil well pumping jack for actuating a sucker rod string in a well tubing, a foambalance pressure tank, a cylinder extending obliquely through the tank, with the axis of said cylinder intersectin and disposed in the vertical plane of the axis of said tank; means connecting the lower end of said tank to the lower end of said cylinder, a piston in said cylinder, a walking beam pivoted on said tank, an arm depending from the underside of one end of said walking beam, a piston rod pivotally interposed between said piston and the lower end of said arm, power means connected to the other end of said walking beam to pivotally reciprocate the latter upon said tank, and means to increase the pressure within said tank during the upstroke of the end of said walking beam to which said power means is connected.

LUTHER A. BLACKBURN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,122,871 Saxe July 5, 1933 2,162,125 Saxe June 13, 1939 2,233,029 Penick Feb. 25, 1941 2,291,499 Penick July 23, 1942

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