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Publication numberUS3868820 A
Publication typeGrant
Publication dateMar 4, 1975
Filing dateFeb 25, 1974
Priority dateFeb 25, 1974
Publication numberUS 3868820 A, US 3868820A, US-A-3868820, US3868820 A, US3868820A
InventorsLawson Joseph M
Original AssigneeLawson Joseph M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Pump control means
US 3868820 A
Abstract
A control means for use with a counterbalanced pump unit including in general a frame, a pump rod leading to a bottom hole pump, counterweights movably mounted from the frame for offsetting the weight of the pump rod, means for driving the counterweights between upper and lower positions, and means for causing the pump rod to move relative to the counterweights. The control means includes cammed means mounted to the frame, cam means mounted to the counterweights and coacting with the cammed means as the counterweights are driven between the upper and lower positions, and linkage means connecting the cammed means to the means for driving the counterweights to regulate the means for driving the counterweights as the cam means coacts with the cammed means causing the counterweights to move between the upper and lower positions in a smooth, even rate.
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Description  (OCR text may contain errors)

United States Patent [191 Lawson 1 Mar. 4, 1975 1 PUMP CONTROL MEANS [76] Inventor: Joseph M. Lawson, PO. Box 518, [57] ABSTRACT Natchez, i 39120 A control means for use with a counterbalanced pump unit including in general a frame, a pump rod leading Flled: 1974 to a bottom hole pump, counterweights movably [211 App} 45 52 mounted from the frame for offsetting the weight of the pump rod, means for driving the counterweights between upper and lower positions, and means for [52] 11.8. C1 60/382, 60/446, 74/8920 causing the pump rod to move relative to the Counter [51] Int. Cl. .l F16h 39/46, Fl5b 15/18 weights The comm] means includes cammed means [58] Field of Search 91/216 B, 218, 327; mounted to the frame, Cam means mounted to the 74/8922 8920; 60/382 counterweights and coacting with the cammed means as the counterweights are driven. between the upper References C'ted and lower positions, and linkage means connecting the UNITED STATES PATENTS cammed means to the means for driving the counter- 36.656 10/1864 Knowles 91/327 weights to regulate the means for driving the counter- 407,338 7/1889 Downie l l 91/327 weights as the cam means coacts with the cammed 904,528 11/1908 Pierce s r r 91/216 B means causing the counterweights to move between 2 3 1 x32 Bender 8 52 the upper and lower positions in a smooth, even rate. 3318 9 awson V r r M V n Primary E.\'aminerPaul E. Maslousky Attorney, Agent, or Firm-John R. Walker, 111

6 Claims, 5 Drawing Figures PUMP CONTROL MEANS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to pumping units and more specifically to control means for use with counterbalanced pumping units for pumping crude oil or the like from wells.

2. Description of the Prior Art The following U.S. patents disclose counterbalanced pump units: Bender, U.S. Pat. No. 3,248,958 and Lawson, U.S. Pat. No. 3,482,399. Neither of the above patents disclose or suggest the present invention.

The U.S. Pat. No. 3,248,958 reference discloses a counterbalanced pump unit which is controlled by means of limit switches. That is, as the travel of the counterweights is completed in one direction, a limit switch is tripped causing a reversal of the movement of the counterweights. The U.S. Pat. No. 3,482,399 reference discloses a counterbalanced pump unit which is controlled by means of cams. That is, as the travel of the counterweights is completed in one direction, a cam is contacted and causes an immediate reversal of the movement of the counterweights.

The known prior counterbalanced pump units are disadvantageous in that they are highly susceptible to failure due to pump rod breakage caused by the high velocities, high and low peak loads, frequent reversals, rod stretch, and overtravel common to counterbalanced pump units.

SUMMARY OF THE INVENTION The present invention is directed towards overcoming the problems and disadvantages in counterbalanced pump units. More specifically, the present invention minimizes pump rod stretch and, thereby, minimizes failure of the pump unit due to pump rod breakage.

The concept of the present invention is to provide a control means adapted to be used with a counterbalanced pump unit which causes the counterweights to revese directions in a smooth, even rate thereby pre venting the builk-up of stress or the like in the pump rod. The control means includes, in general, cam means, cammed means for coacting with the cam means as the counterweights are driven between upper and lower positions, and linkage means for connecting the cammed means to means for driving the counterweights to cause the counterweights to move between the upper and lower positions in a smooth, even rate. Preferably, stop means is included to prevent over travel of the cammed means.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat simplified front elevational view of a counterbalanced pump unit including the control means of the present invention.

FIG. 2 is an end elevational view of FIG. 1.

FIG. 3 is detailed view of a portion of the linkage means of the present invention.

FIG. 4 is a detailed view of the stop means of the present invention.

FIG. 5 is a detailed view ofa portion of the means for driving the counterweights of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The control means 11 of the present invention is for use with a counterbalanced pump unit such as the pump unit 13 illustrated known to those skilled in the art. In general, the counterbalanced pump unit 13 includes a frame 15, a pump rod 17 leading to a bottom hole pump (not shown) in a typical oil well 19 or the like, counterweights 21 movably mounted from the frame 15 preferably by means of a carriage 23, means for driving the counterweights 21 between upper and lower positions, and means for causing the pump rod 17 to move relative to the counterweights 21. The frame 15 preferably includes a crown post 15', a rear post 15', and a horizontal beam 15". The means for driving the counterweights 21 between upper and lower positions preferably includes a motor 25, a hydraulic pump 27, a hydraulic cylinder 29, a piston rod 31, and hydraulic lines 33 between the hydraulic pump 27 and the piston rod 31. The hydraulic cylinder 29 and the piston rod 31 are preferably of the type disclosed in the U.S. Pat. No. 3,482,399 reference with the carriage 23 being attached to the hydraulic cylinder 29 by any means well known to those skilled in the art such as the gimbal assembly disclosed in the U.S. Pat. No. 3,482,399 reference, with the upper end of the piston rod 31 attached to the frame 15 through an anchor joint 35 allowing universal pivot pin movement of the piston rod 31 while preventing any vertical movement thereof, and with the lower end of the piston rod free for lateral movement.

The means for causing the pump rod 17 to move relative to the counterweights 21 preferably includes first and second sheaves 37, 39 rotatably mounted on the upper portion of the crown post 15' 0f the frame 15; third and fourth sheaves 41, 43 rotatably mounted on the hydraulic cylinder 29; a pump rod hanger 45 fixedly attached to the upper end of the pump rod 17; a first flexible cable 47 having a first end fixedly attached to the pump rod hanger, having a body portion extending around the first sheave 37 and the third sheave 45, and having a second end fixedly attached to the horizontal beam 15' of the frame 15; and a second flexible cable 49 having a first end fixedly attached to the pump rod hanger 45, having a body portion extending around the second sheave 39 and the fourth sheave 43, and having a second end fixedly attached to the horizontal beam 15" of the frame 15. As thus constructed, the means for causing the pump rod to move relative to the counterweights 21 gives the pump rod 17 twice the travel of the counterweights 21. However, it should be noted that any such construction well known to those skilled in the art may be used.

The control means 11 of the present invention includes in general cammed means 51 mounted to the frame 15, cam means 53 fixedly mounted on the counterweights 21 for coacting with the cammed means 51, and linkage means 55 connecting the cammed means 51 to the means for driving the counterweights 21 for regulating the means for driving the counterweights 21 to cause the counterweights 21 to move between the upper position and the lower position in a smooth, even rate. The cammed means 51 includes a shaft 57 rotatably mounted preferably to the rear post 15" of the frame 15 by support members 5'9, a first cylindrical cammed member 61 fixedly mounted on a first end 57' of the shaft 57 having a cam surface 61, and a second cylindrical cam 63 fixedly mounted on a second end 57" of the shaft 57 having a cam surface 63'.

The cam means 53 includes in general an arm 65 fixedly mounted to the counterweights 21 and a roller 67 rotatably mounted on the arm 65 for coacting with the cam surfaces 61 63 of the first and second cylindrical cammed members 61, 63.

The linkage means 55 includes, in general, a first rigid member 69 (FIG. 3) fixedly connected to the shaft 57 for rotation therewith and a second rigid member 71 having a first end pivotally mounted to the first rigid member 69 and having a second end pivotally mounted to the hydraulic pump 27. As thus constructed, the linkage means transfers movement of the shaft 57 to the hydraulic pump 27 to control the output of the hydraulic pump 27 and thereby controls the movement of the counterweights 21. Preferably, the second rigid member 71 includes a turnbuckle means 73 and a flexible connection 75.

The control means 11 includes flywheel means 77 coactively mounted to the shaft 57 for temporarily storing the momentum of the rotation of the shaft 57 to cause rotation of the shaft 57 to continue after the counterweights 21 have reached the upper or lower position. The flywheel means 77 preferably includes a first sprocket 79 fixedly attached to the shaft 57, a second sprocket 81 fixedly attached to a second shaft 83 that is rotatably mounted from the rear post of the frame 15 by support members 85, a continuous chain 87 connecting the first sprocket 79 to the second sprocket 81, and a flywheel 89 fixedly mounted to the second shaft 83. The first sprocket 79 is of a larger diameter than the second sprocket 81 so that one complete revolution of the shaft 57 will cause more than one complete revolution ofthe second shaft 83. Preferably, the ratio between the first sprocket 79 and the second sprocket 81 is 15-20 to 1. A clutch means 91 is preferably provided adjacent the flywheel 89 to dissipate excessive momentum of the flywheel 89 after the rotation of the shaft 57 is stopped.

The control means 11 is preferably provided with a stop means 93 for stopping the rotation of the shaft 57 after a fixed amount of rotation. The stop means 93 preferably includes an arm portion 95 fixedly mounted to the shaft 57, a platform member 97 fixedly mounted to support structure such as the frame 15 or the like adjacent the arm member 95, and first and second stop members 99, 101 mounted on the platform member 97 so that when the arm member 95 is rotated a fixed amount such as 70, it contacts either the first or second stop member 99, 101 and is thereby prevented from further rotating. Preferably, the first and. second stop members 99, 101 are manually adjustable to allow the amount of rotation of the arm member 95 and, therefore, the shaft 57 to be varied or graduated. More specifically, the platform member 97 is preferably provided with a plurality of apertures 99' for selectively receiving the first stop member 99 and a plurality of apertures 101' for selectively receiving the second stop member 101. The apertures 99', 101 are located at predetermined positions on the platform member 97 so that the first and second stop members 99, 101 may be adjusted to allow the arm member 95 to rotate various amounts such as 60, 70or 80. it should be noted that the first and second stop members 99, 101 can be selectively received in the apertures 99, 101' by any means well known to those skilled in the art such as by screw threads or the like.

The hydraulic pump 27 is of the well known variable displacement type which is controlled by a manually operated servo valve 103 (See, for example, US. Pat. No. 3,482,399). The servo valve 103 regulates both the volume output and the direction of flow from the pump 27. In general, the servo valve 103 includes a control arm 105 having a first definite position in which the volume output of the pump 27 is at its maximum and in which the direction of flow is in a first direction, having a second definite position in which the volume output of the pump 27 is at its maximum and in which the direction of flow is in a second direction opposite from the first direction, and having a definite neutral position between the first and second definite positions in which there is no flow from the pump 27. As the control arm 105 is moved between the first definite position and the definite neutral position or the second definite position and the definite neutral position, the volume output of the pump 27 is varied by an amount proportional to the amount of movement. That is, as the control arm 105 is moved away from the definite neutral position towards either the first or second definite position, the volume output ofthe pump 27 is increased until the volume output is at a maximum when the control arm 105 is at either the first or second definite position. On the other hand, as the control arm 105 is moved toward the definite neutral position away from either the first or second definite positions, the volume output of the pump 27 is decreased until there is no flow when the control arm is at the definite neutral position. It should be noted that the servo valve 103 includes first and second stop portions 107, 109 for preventing movement of the control arm 105 beyond the first or second definite position. in addition, the stop portions 107, 109 are preferably of variable sizes to alter the positions of the first and second definite positions thereby varying the maximum volume output of the pump 27. That is, by increasing the size of the stop portions 107, 109 the first and second definite positions are moved closer to the definite neutral position thereby decreasing the maximum volume output of the pump 27. The first and second stop portions 107, 109 may be of different sizes to cause the maximum volume output of the pump to be different between the first and second definite positions. Similarly, the turnbuckle means 73 may be utilized to vary the maximum volume output of the pump 27. That is, increasing or decreasing the length of the second rigid member 71 will cause the movement of the control arm 105 to be increased in one direction and decreased in the other thereby varying the amount of control the linkage means 55 has over the pump 27.

The operation of the present invention is as follows: as the counterweights 21 approach the upper position, the roller 67 of the cam means 53 contacts the cam surface 61' of the first cylindrical cammed member 61 causing the shaft 57 to rotate. As the shaft 57 rotates, the linkage means 55 moves the control arm 105 of the servo valve 103 away from the first definite position towards the definite neutral position causing the volume output of the pump 27 to decrease, thereby slowing down the movement of the counterweights 21. As the roller 67 of the cam means 53 continues to cause the first cylindrical cammed member 61 to rotate the shaft 57, the control arm 105 will be moved to the definite neutral position in which there is no flow from the pump 27 and, thus, the movement of the counterweights 21 will stop. However, due to the flywheel means 77, the rotation of the shaft 57 will continue causing the control arm 105 to be moved past the definite neutral position towards the second definite position so that the flow from the pump 27 will cause the counterweights 21 to begin movement towards the lower position. The shaft 57 will continue its rotation until stopped by the stop means 93. When the stop means 93 causes the shaft 57 to stop rotating, the control arm 105 is in the second definite position and the volume output of the pump 27 is at its maximum. As the counterweights 21 move towards the lower position, the roller 67 of the cam means 53 contacts the cam surface 63 of the second cylindrical cammed member 63 causing the shaft 57 to rotate in the opposite direction from that caused by the coaction of the cam means 53 and the first cylindrical cammed member 61, thereby, causing the control arm 105 to move away from the second definite position towards the def inite neutral position. After the control arm 1115 reaches the definite neutral position and causes the counterweights 21 to stop movement, the shaft 57 continues rotating because of the flywheel means 77 and causes the control arm 105 to move from the definite neutral position towards the first definite position thereby causing the counterweights 21 to start movement towards the upper position again. The shaft 57 will continue rotating until stopped by the stop means 93 with the control arm 105 in the first definite position and with the volume output of the pump 27 at its maximum. As the counterweights 21 move towards the upper position, the above described process is repeated.

As thus constructed and operated, the present invention allows movement of the counterweights 21 in a smooth, even rate to prevent failure of the pump rod 17 due to stresses being set up in the pump rod 17 as a result ofthe high velocities, high and low peak loads, frequent reversals, rod stretch, and over travel common to counterbalanced pump units. A counterbalanced pump unit 13 having the control means 11 of the present invention is capable by the use of direction of flow and volume output variations of the hydraulic pump 27 of maintaining equal speed on the up and down strokes of the counterweights 21 between the upper position and the lower position, of maintaining a fast upstroke and a slow downstroke, or of maintaining a slow upstroke and a fast downstroke. The advantages of maintaining such stroke speeds are well known to those skilled in the art.

Although the invention has been described and illustrated with respect to a preferred embodiment thereof, it is not to be so limited since changes and modifications may be made therein which are within the full intended scope of the invention.-

I claim:

1. A control means for use with a typical counterbalanced pump unit including in general a frame, a pump rod. counterweights for offsetting the weight of the pump rod, means for driving the counterweights between upper and lower positions, and means causing the pump rod to move relative to the counterweights, said control means comprising:

a. cammed means for mounting to the frame;

b. cam means for fixedly mounting on the counterweights and for coacting with said cammed means as the counterweights are driven between the upper and lower positions to cause said cammed means to rotate;

c. linkage means for connecting said cammed means to the means for driving the counterweights to regulate the means for driving the counterweights to cause the counterweights to move between the upper and lower positions in a smooth, even rate as said cam means causes said cammed means to rotate;

d. means for temporarily storing the momentum of the rotation of said cammed means to cause rotation of said cammed means to continue after the counterweights have reached the upper or lower position;

e. stop means for stopping the rotation of said cammed means after a fixed amount of rotation; and

f. means for dissipating excessive momentum of said means for temporarily storing the momentum of the rotation of said cammed means after the rotation of said cammed means is stopped.

2. The control means of claim 1 in which said cammed means includes:

a. shaft means for rotatably mounting to the frame,

said shaft means having first and second ends;

b. a first cylindrical cammed member fixedly mounted on said first end of said shaft means for coacting with said cam means when the counterweights are being driven to the upper position to cause rotation of said shaft means in a first direction; and

c. a second cylindrical cammed member fixedly mounted on said second end of said shaft means for coacting with said cam means when the counterweights are being driven to the lower position to cause rotation of said shaft means in a second direction.

3. The control means ofclaim 2 in which said linkage means is fixedly connected to said shaft means so that when said shaft means is rotated in the first direction said linkage means causes the means for driving the counterweights to drive the counterweights in the upper direction and when said shaft means is rotated in the second direction said linkage means causes the means for driving the counterweights to drive the counterweights in the lower direction.

4. The control means of claim 3 in which said linkage means includes turnbuckle means for varying the length of said linkage means to vary the amount of control over the means for driving the counterweights.

5. A control means for use with a typical counterbalanced pump unit including in general a frame, a pump rod leading to a bottom hole pump, counterweights movably mounted on the frame for offsetting the weight of the pump rod, means for driving the counterweights between upper and lower positions, and means for causing the pump rod to move relative to the counterweights, said control means comprising:

a. cammed means including shaft means for rotatably mounting to the frame, a first cylindrical cammed member fixedly mounted on a first end of said shaft means, and a second cylindrical cammed member fixedly mounted on a second end of said shaft means;

b. cam means for fixedly mounting on the counterweights and for coacting with said first cylindrical cammed member when the counterweights are being driven to the upper position to cause rotation of said shaft means in a first direction and for coacting with said second cylindrical cammed member when the counterweights are being driven to the lower position to cause rotation of said shaft means in a second direction;

c. flywheel means coactively mounted to said shaft means for temporarily storing the momentum of the rotation of said shaft means to cause rotation of said shaft means to continue after the counterweights have reached the upper or lower position;

(1. stop means for stopping the rotation of said shaft means after a fixed amount of rotation;

e. clutch means for dissipating excessive momentum of said flywheel means after the rotation of said shaft means is stopped; and

f. linkage means for connecting said shaft means to the means for driving the counterweights so that when said shaft means is rotated in the first direc tion said linkage means causes the means for driving the counterweights to drive the counterweights in the upper direction and when said shaft means is rotated in the second direction said linkage means causes the means for driving the counterweights to drive the counterweights in the lower direction.

6. The combination with a typical counterbalanced pump unit including in general a frame, a pump rod leading to a bottom hole pump, counterweights movably mounted on the frame for offsetting the weight of the pump rod, means for driving the counterweights between upper and lower positions, and means for causing the pump rod to move relative to the counterweights, of control means for controlling the means for driving the counterweights to allow the counterweights to move between the upper and lower positions with equal or unequal speed in a smooth, even rate, said control ineans comprising:

a. cammed means including shaft means rotatably mounted to the frame, a first cylindrical cammed member fixedly mounted on a first end of said shaft means, and a second cylindrical cammed member fixedly mounted on a second end of said shaft means;

b. cam follower means fixedly mounted on the counterweights for coacting with said first cylindrical cammed member when the counterweights are being driven to the upper position to cause rotation of said shaft means in a first direction and for coacting with said second cylindrical cammed member when the counterweights are being driven to the lower position to cause rotation of said shaft means in a second direction;

c. linkage means connecting said shaft means to the means for driving the counterweights so that when said shaft means is rotated in the first direction said linkage means causes the means for driving the counterweights to drive the counterweights in the upper direction and when said shaft means is rotated in the second direction said linkage means causes the means for driving the counterweights to drive the counterweights in the lower direction;

d. flywheel means coactively mounted to said shaft means for temporarily storing the momentum of the rotation of said shaft means to cause rotation of said shaft means to continue after the counterweights have reached the upper or lower position;

e. stop means for stopping the rotation of said shaft means after a fixed amount of rotation; and f. clutch means for dissipating excessive momentum of said flywheel means after the rotation of said

Patent Citations
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US3248958 *Apr 2, 1962May 3, 1966Emil A BenderWire line deep well pumping apparatus
US3482399 *Feb 27, 1968Dec 9, 1969Lawson Joseph MPump operating unit
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3959967 *Jun 6, 1975Jun 1, 1976Centre D'etudes Et De Realisations Industrielles De L'atlantique C.E.R.I.A.Reciprocating apparatus particularly for pump unit
US4020707 *Jan 1, 1975May 3, 1977Owens-Illinois, Inc.Motion translating apparatus and controls therefor
US4062640 *Sep 24, 1976Dec 13, 1977Bethlehem Steel CorporationMethod and means for controlling long stroke pumping units
US4391155 *Jun 28, 1982Jul 5, 1983Bender Emil AReciprocating drive and reversing mechanism for long stroke, well pumping unit
US5735170 *Sep 11, 1995Apr 7, 1998Bales; Donald R.Pumping unit with dynamic fluid ballast
US6041597 *Jun 22, 1998Mar 28, 2000Huang; Chih-HsiangPneumatic/hydraulic balance weight system for mother machines
US6348000 *Feb 12, 1999Feb 19, 2002Ap Time LimitedTorsional vibration dampers
Classifications
U.S. Classification60/382, 74/89.2, 60/446
International ClassificationF04B47/02, F04B47/00, F04B47/14
Cooperative ClassificationF04B47/14, F04B47/02
European ClassificationF04B47/14, F04B47/02