Compact well pumping unit actuated by linear motor with counterweight directly attached to slider

Abstract

A compact well pumping unit actuated by a linear motor with one or more counterweights directly attached to the slider. In one embodiment, two slider units are joined to form a rectangular complex around a two-sided stator track mounted vertically inside of a vertical steel frame. A belt assembly connects the slider complex to the polished rod of the well pump. The belt assembly passes over a first set of pulley wheels mounted on top of the vertical steel frame and a second set mounted on the side of the vertical steel frame. Thus when the slider complex caused to moves up and down, the polished rod of the well pump is actuated by the linear motor.

1 . A well pumping unit comprising:
 (a) a well pump affixed to the wellhead of an oil well;   (b) a vertical support structure located adjacent to the well pump;   (c) a first set of overturned pulley wheels mounted on top of the vertical support structure;   (d) a second set of overturned pulley wheels mounted on the side of the vertical support structure facing the well pump and near the top of the vertical support structure;   (e) a two-sided stator track having a plurality of magnets on each side, said stator track is mounted vertically inside of and parallel to the vertical support structure, said stator track having rails running vertically on both sides of the stator track;   (f) a linear motor assembly having two symmetrical electromagnetic sliders joined together and affixed movably on the stator track, said linear motor assembly having one or more detachable counterweight;   (g) said electromagnetic sliders having two sets of roller wheels running on rails along each side of the stator track;   (h) one or more belts having one end attached to the linear motor assembly, passing through the first set and then the second set of overturned pulley wheels, and having the other end attached to the well pump;   (i) a control system for providing regulated and controlled low-voltage electric power to the linear motor assembly; and   
     whereby when power is provided to the motor assembly, the electromagnetic sliders will move in either linear vertical direction parallel to the stator plate causing the belt to move the well pump in the opposite vertical direction to extract liquid from the oil well. 
   
   
       2 . The well pumping unit of  claim 1 , wherein the electromagnetic slider can be braked by one or more electromagnetic brakes comprising of an electromagnetic switch, a pair of brake pads, and a mechanical means to squeeze the brake pads on the stator track; whereby when electricity is applied, the electromagnetic switch uses the mechanical means to causes the brake pads to squeeze the stator track, thus braking the slider on the stator track. 
   
   
       3 . The well pumping unit of  claim 1 , the electromagnetic slider is protected by bumpers placed above and below the stator track; said bumpers are made of soft elastic material. 
   
   
       4 . The well pumping unit of  claim 1 , wherein the linear motor assembly is connected by wire to a control panel; said control panel monitors and controls the linear motor assembly. 
   
   
       5 . The well pumping unit of  claim 1 , wherein the electromagnetic slider contains a fan to cool the electromagnetic slider. 
   
   
       6 . A device for actuating a rod of a sucker rod pump assembly, the device comprising:
 (a) a vertical support structure located adjacent to the sucker rod pump assembly;   (b) a linear motor comprising:
 (i) a stator track mounted vertically on the vertical support structure, 
 (ii) a slider able to slide on the stator track, said slider having one or more detachable counterweight, and 
 (iii) a guideway means to stabilize the slider sliding on the stator track; 
   (c) one or more elongate flexible member, said elongate flexible member having one end attached to the slider and the other end attached to the rod; and   (d) a wheel means for reversing the direction of the force urged on the two ends of the elongate flexible member, said wheel means is mounted on the vertical support structure above the stator track;   
     whereby when power is provided to the linear motor:
 (a) the slider is urged to slide up and down the stator track; 
 (b) the end of the elongate flexible member attached to the slider moves in the same direction as the slider; 
 (c) the direction of the force exerted on the elongate flexible member is reversed by said wheel means; and 
 (d) the end of the elongate flexible member attached to the rod moves in the opposite direction as the slider, thereby actuating the rod. 
 
   
   
       7 . The device of  claim 6 , wherein the vertical support structure is a steel frame constructed from four standing steel beams connected by a plurality of horizontal and diagonal steel beams. 
   
   
       8 . The device of  claim 7 , wherein the stator track is mounted inside of the steel frame. 
   
   
       9 . The linear motor of  claim 6 , wherein the slider contains a plurality of electromagnetic coils and the stator track contains a plurality of magnets. 
   
   
       10 . The stator track of  claim 9 , wherein the plurality of magnets is covered by a thin stainless steel cover with less magnetic conductivity. 
   
   
       11 . The linear motor of  claim 6 , wherein the stator track is a two-sided stator track sandwiched between two sliders that are joined together. 
   
   
       12 . The linear motor of  claim 6 , wherein the guideway means to stabilize the slider sliding on the stator track is comprised of:
 (a) a plurality of wheels mounted on the slider, and   (b) one or more rail mounted on the vertical support structure, said rail is mounted parallel to the stator track; whereby when the slider slides on the stator track, the wheels mounted on the slider roll on the rail, thus guiding the vertical course of the slider on the stator track while maintaining a consistent horizontal position.   
   
   
       13 . The device of  claim 6 , wherein the elongate flexible member is selected from the group consisting of a belt, chain, rope, cable, strap, or equivalent thereof. 
   
   
       14 . The device of  claim 6 , where in the elongate flexible member is a belt composed a plurality of steel cables enclosed within rubber. 
   
   
       15 . The device of  claim 6 , wherein the wheel means for reversing the direction of the force urged on the two ends of the elongate flexible member is selected from the group consisting of a pulley, overturned wheel, roller, gear or equivalent thereof. 
   
   
       16 . The device of  claim 6 , wherein the elongate flexible member passes over a wheel means for positioning the elongate flexible member directly above the rod; said wheel means is mounted on the upper end of the vertical support structure on the side of the vertical support structure facing the sucker rod pump assembly; said wheel means is selected from the group consisting of a pulley, overturned wheel, roller, gear or equivalent thereof. 
   
   
       17 . The device of  claim 6 , wherein the slider can be braked by one or more electromagnetic brake comprising of an electromagnetic switch, a pair of brake pads, and a mechanical means to squeeze the brake pads on the stator track; whereby when electricity is applied, the electromagnetic switch uses the mechanical means to causes the brake pads to squeeze the stator track, thus braking the slider on the stator track. 
   
   
       18 . The device of  claim 6 , wherein the slider is protected by bumpers placed above and below the stator track; said bumpers are made of soft elastic material. 
   
   
       19 . The device of  claim 6 , wherein the slider contains a fan to cool the slider. 
   
   
       20 . The device of  claim 6 , wherein the slider contains an oil tank to lubricate the guideway means to stabilize the slider. 
   
   
       21 . The device of  claim 6 , wherein the linear motor is connected by wire to a control panel; said control panel monitors and controls the linear motor. 
   
   
       22 . The linear motor of  claim 21 , wherein the stroke and speed of the slider can be adjusted on the control panel when the linear motor is in operation. 
   
   
       23 . The device of  claim 21 , wherein the force and power consumption of the linear motor and the lag time of the slider can be adjusted on the control panel when the linear motor is not in operation. 
   
   
       24 . The device of  claim 21 , wherein the linear motor automatically shuts off when:
 (a) the temperature of the slider is above a preset temperature;   (b) the load on the linear motor is above or below a preset range;   (c) the voltage on the linear motor is above or below a preset range; or   (d) the current on the linear motor is above or below a preset range.   
   
   
       25 . A method for pumping a fluid utilizing a sucker rod assembly, a vertical support structure, a linear motor, a pulley wheel, one or more counterweight, one or more elongate flexible member and one or more rail; the sucker rod assembly including a rod, the linear motor including a slider and a stator track, the slider having a plurality of wheels, the elongate flexible member having two ends; the method comprising:
 (a) positioning the sucker rod pump assembly such that the pump contacts a fluid reservoir;   (b) positioning the vertical support structure adjacent to the sucker rod pump assembly;   (c) mounting the pulley wheel on top of the vertical support structure;   (d) mounting the stator track on the side of the vertical support structure opposite of the sucker rod pump assembly;   (e) mounting the rail to the vertical support structure such that the rail is parallel to and adjacent to the stator track;   (f) attaching one end of the elongate flexible member to the rod;   (g) positioning the elongate flexible member over the pulley wheel;   (h) attaching the other end of the elongate flexible member to the slider;   (i) positioning the slider on stator track such that the wheels of the slider roll on the rail;   (j) attaching the counterweight on the slider such that it alleviates the load imposed on the linear motor by the sucker rod and the column of fluid to be pumped; and   (k) operating the linear motor such that the pump acquires fluid on its down stroke and transports fluid on its up stroke.