Abstract: A lubrication distribution assembly is provided. The lubrication distribution assembly includes a lubrication metering device, which includes a piston. The lubrication distribution assembly also includes a sensor and a controller. The sensor automatically detects a piston stroke length of the piston over at least two movement cycles of the piston. The controller receives the piston stroke length from the sensor, sets an operating point of the piston based on the piston stroke length, and controls the lubrication metering device by utilizing the set operating point.

Abstract: Electro-hydraulic work vehicle system having a hydraulic lift mechanism comprising a first electric machine, a first hydraulic machine operatively connected to the first electric machine. A load holding valve is switchable between a first position in which it retains pressurized fluid in the hydraulic lift mechanism and a second position in which it enables pressurized fluid to flow between the first hydraulic machine and the hydraulic lift mechanism. A pressure relief valve is switchable between a first, initial position in which it prevents pressurized fluid from flowing from the first hydraulic machine to the hydraulic tank and a second position in which it enables pressurized fluid to flow from the first hydraulic machine to the hydraulic tank.

Abstract: Adaptable systems for a surface pumping unit that includes a low inertia pumping unit mechanism having a pneumatic counterbalance assembly are described, as well as methods for the use of such systems for subterranean fluid recovery. The system is capable of being integrated with well management automation systems, thereby allowing for response to active control commands, and automatically altering and/or maintaining a counterbalance force in the pumping unit by adding or removing air mass from a containment vessel associated with the pumping unit.

Abstract: Disclosed is a power unit of a hydraulic pumping unit, which comprises a motor; a pumping rod driving device for driving reciprocating movement of a pumping rod; a variable pump driven by the motor, the variable pump hydraulically connected to the pumping rod driving device; a secondary hydraulic control unit hydraulically connected to the pumping rod driving device; an energy accumulator being in transmission connection with the secondary hydraulic control unit; a sensor for setting a stroke of the pumping rod; a first control device adapted to, based on the signals from the sensor, set the discharge capacity of the variable pump to be zero during the declining process of the pumping rod and to be positive during the ascending process of the pumping rod to drive the pumping rod driving device; and a second control device adapted to based on the signals from the sensor, set the secondary hydraulic control unit to function as a motor for driving the energy accumulator to accumulate energy during the descending

Abstract: A potential energy store has a hydraulic cylinder in which a piston for storing energy in the form of potential energy of the piston is arranged. A position of the piston relative to the earth's surface can be varied. A pump pumps hydraulic fluid via lines into the hydraulic cylinder such that the piston is raised. A generator converts hydraulic energy of hydraulic fluid, which is displaced out of the hydraulic cylinder as the piston falls, into electricity. A seal arrangement is at least partially arranged between the hydraulic cylinder and the piston. The seal arrangement has a sealing section with a flexible support structure for absorbing the acting forces. The support structure may be coated on one or both sides with a layer which is impervious to fluid and which seals against the passage of fluid or may be impregnated with a solidified material which is impervious to fluid.

Abstract: A method and a mechanism for releasing a hydraulically actuated elevator brake system wherein the brake release mechanism includes a rotary pump, a crank handle to manually turn the rotary pump, a fluid supply port, a fluid return port, an output port for connection to a cylinder of the brake system, a rapid exhaust valve having an inlet port connected via the rotary pump to the fluid supply port, a cylinder port selectively connectable to the output port, and an exhaust port connected to the fluid return port. By turning the rotary pump, for example with the crank handle, a continuous flow of pressurized hydraulic fluid is delivered through the rapid exhaust valve and onto the brake cylinder, thereby releasing the hydraulic brake system.

Abstract: A pumping assembly includes a hydraulic pump having a hydraulic ram tied to a reciprocating annular piston having a central bore. When the annular piston moves in an upward direction, the hydraulic ram moves toward an extended position extending from the housing. When the annular piston moves in a downward direction, the hydraulic ram moves toward a retracted position retracted within the housing. A polish rod extends up through the central bore of the annular piston and is held in position by a polish rod clamp positioned on top of the hydraulic ram. The polish rod moves with the hydraulic ram. Other pumping systems, devices, and methods are also disclosed.

Abstract: An open loop heat pipe radiator comprises a radiator tube and a free-piston. The radiator tube has a first end, a second end, and a tube wall, and the tube wall has an inner surface and an outer surface. The free-piston is enclosed within the radiator tube and is capable of movement within the radiator tube between the first and second ends. The free-piston defines a first space between the free-piston, the first end, and the tube wall, and further defines a second space between the free-piston, the second end, and the tube wall. A gaseous-state working fluid, which was evaporated to remove waste heat, alternately enters the first and second spaces, and the free-piston wipes condensed working fluid from the inner surface of the tube wall as the free-piston alternately moves between the first and second ends. The condensed working fluid is then pumped back to the heat source.

Abstract: The disclosed invention introduces an efficient lifting mechanism for reciprocating vertically a load system, the load consisting of the aggregate weights of a cargo payload in conjunction with “dead weights” of moving parts of the lifting apparatus. The disclosed invention uses a hydro-pneumatic linear actuator to lift the load and a pressurized accumulator, acting as a force intensifier. The pressurized accumulator, acting as a self-contained stored energy source, provides to the actuator adequate power to lift the “dead weights” plus part of the cargo payload. An external power source provides to the actuator adequate power to lift the remainder of the cargo payload. The disclosed invention saves significant amounts of power and energy in applications in which the “dead weights” are sizable compared to the cargo load. The disclosed invention provides also exceptional means for accurate motion control of the cargo payload.

Abstract: The present invention relates to an implement, in particular an excavator or machine for material handling, with an element movable via at least one working drive, wherein at least one energy recovery cylinder is provided for energy recovery from the movement of the movable element, which includes a chamber filled with gas, wherein the actuation of the implement is effected in dependence on the directly or indirectly determined temperature of the gas in the chamber filled with gas.

Abstract: An energy management system includes an energy storage reservoir and a fluid pump. The reservoir includes a fluid reservoir configured to contain varying quantities of a fluid and to isolate the fluid from the ambient. The fluid reservoir has a top surface, bottom surface, flexible member, and at least one opening for filling or emptying the reservoir. A pressing mass of solid material is positioned above the fluid reservoir with a weight sufficient to press the reservoir and empty the reservoir of fluid when the reservoir opening is open. The pressing mass is supported by the fluid reservoir when the reservoir contains fluid and is closed. The flexible member is disposed around the fluid reservoir to seal the fluid and to facilitate vertical motion of the pressing mass as the reservoir is filled and emptied. The pump supplies fluid to the fluid reservoir via the opening.

Abstract: The present invention relates to a piece of working equipment, in particular to an excavator or to a machine for the transfer of material, having an element movable via at least one working hydraulic cylinder, wherein at least one energy recovery hydraulic cylinder is provided for the recovery of energy from the movement of the movable element. In accordance with the invention, the energy recovery hydraulic cylinder is filled with gas at the bottom side and has a hollow piston rod.

Abstract: A reciprocating drive apparatus for connection to a top end of a rod swing to drive a downhole pump located in a well includes a plate adapted to be fastened to a top end of a well head assembly of the well, and a mast attachable to the plate in a substantially vertical working position. A hydraulic cylinder is attached to the mast such that when the mast is in the working position the hydraulic cylinder is oriented substantially vertically, and such that the hydraulic cylinder can extend and retract in response to a controller. A tether is adapted to be fixed to the well head and to the top end of the rod string and is configured such that the hydraulic cylinder engages the tether to move the rod string up and down as the hydraulic cylinder extends and retracts.

Abstract: An unlimited stroke drive method for pumping fluid from an oil well in which the well has a tubing string extending from the earth's surface down to a fluid producing formation. The method includes the steps of positioning a pump barrel within the tubing, an upper end of the pump barrel having communication through a standing valve with the interior of the tubing string, vertically reciprocating a length of flexible cable within the tubing string to vertically reciprocate a plunger within the pump barrel to allow a lower portion to quickly fill with fluid from the producing formation and then to a downward position in which fluid within the pump barrel lower portion is transferred through a traveling valve to an area within the pump barrel above the plunger to move formation fluid from within the pump barrel to the interior of the tubing and thence to the earth's surface.

Abstract: A reciprocating body 12 is reciprocably housed in a cylinder body 6, and a pressure rod 20 is reciprocably attached to this reciprocating body 12. A pressure end 20a of the pressure rod 20 protrudes from the cylinder body 12 toward the outside. By the reciprocating body 12 and diaphragms 17 to 19, an advance pressure chamber 27 and a weight offset pressure chamber 29 are partitioned and formed in the cylinder body 6. After the pressure end 20a is disposed vertically downwardly, the weight offset pressure chamber 29 is filled with compressed fluid, whereby self weight of the reciprocating body 12 and the pressure rod 20 is offset. Then, the compressed fluid is supplied to the advance pressure chamber 27, and an object to be pressurized W is pressurized through the pressure rod 20.

Abstract: An electrochemical analyte sensor formed using conductive traces on a substrate can be used for determining and/or monitoring a level of analyte in in vitro or in vivo analyte-containing fluids. For example, an implantable sensor may be used for the continuous or automatic monitoring of a level of an analyte, such as glucose, lactate, or oxygen, in a patient. The electrochemical analyte sensor includes a substrate and conductive material disposed on the substrate, the conductive material forming a working electrode. In some sensors, the conductive material is disposed in recessed channels formed in a surface of the sensor. An electron transfer agent and/or catalyst may be provided to facilitate the electrolysis of the analyte or of a second compound whose level depends on the level of the analyte. A potential is formed between the working electrode and a reference electrode or counter/reference electrode and the resulting current is a function of the concentration of the analyte in the body fluid.

Abstract: The invention relates to a drive device for a hydraulic elevator, the device comprising an actuator (1) whose pressure chamber (1a) is connected to a pump (11) via a down duct (15) and via an up duct (16). A pressure accumulator (4) is connected to the down and up ducts (15, 16) via parallel ducts (15a, 16a), each duct having an electrically controlled valve (2, 2a; 6, 6a). While the elevator is moving downwards, hydraulic fluid is transferred from the pressure chamber (1a) to the accumulator (4) via the down duct (15) and the parallel duct (16a). While the elevator is moving upwards, hydraulic fluid is transferred from the accumulator (4) to the pressure chamber (1a).

Abstract: A control module system provides convenient and economical operation of downhole tools, which operation is controllable from a remote location. In a described embodiment, a control module system includes a control circuit configured to control selective opening of a plurality of valves interconnected between a plurality of accumulators and multiple tools, all positioned within the well. Additionally, the control circuit communicates with a terminal at the earth's surface for transmitting instructions from the terminal to the control circuit, and for transmitting data from the control circuit to the terminal.

Abstract: This pneumatic stroke reversal system for reciprocating, linearly driven pumping units is completely automatic in its cyclic operation, and greatly improves efficiency. A smaller drive motor is required because kinetic energy is stored at the end of each stroke, to be returned to the system to assist in beginning and accelerating the following stroke, and because the smooth and controlled reversals allow a substantially higher stroke velocity and production from a unit of a given size. The reversals are effective on both the upstroke and the downstroke, and their maximum net values are individually selectable over a wide range, and adjustable in the field. The exact points of direction change occur at the instant of maximum rod stretch and maximum rod contraction, respectively, thereby greatly reducing parasitic rod string oscillation, and reducing pressure peaks on, and problems with, the rod string.

Abstract: A hydraulic oil well pump drive system for driving an oil well sucker rod includes a master piston positioned within a master cylinder for axial displacement between first and second ends of the master cylinder. The master piston has a piston drive rod which extends through one end of the master cylinder. The drive rod is connected to a crank pin of an eccentric crank. A center seal assembly divides the master cylinder into a working chamber and a pressure chamber in opposite ends of the master cylinder. Each respective chamber defines a fluid volume which varies with the displacement of the master piston. The master piston displacement creates a bi-directional flow of working fluid from the working chamber. A wellhead hydraulic assembly is operably connected to the oil well sucker rod and is in fluid communication with the master cylinder working chamber to receive the working fluid flow.

Abstract: A fluid system is connected to a three chamber fluid cylinder. The effective pressure responsive areas of two of the pressure chambers are equal such that when fluid at a selected rate of flow and at a predetermined pressure is communicated to one of the chambers, a force of a predetermined magnitude is generated to cause contraction of the fluid cylinder at a predetermined rate. A servo valve is disposed in the system between the inlet and outlet of a fluid pump to selectively direct fluid to either of the equal pressure chambers to selective expand or contract the fluid cylinder. The fluid system further comprises an accumulator and a directional control valve adapted to communicate a third chamber of the fluid cylinder to the accumulator. The accumulator maintains the pressure in the third fluid chamber to exert a force on the fluid cylinder balancing a selected load that the cylinder may be carrying during the expansion and contraction stages of the cylinder.

Abstract: This pumping unit stroke reversal invention can be employed in various embodiments, and uses one or more resilient hydraulic-pneumatic accumulators which slow and stop each stoke, storing the kinetic energy, and returning this energy to begin and accelerate the next succeeding stroke. This storing and re-application of energy greatly increases the efficiency of any pumping unit which incorporates the stroke reversal system of this invention. Counterbalance force is mechanical, hydraulic-pneumatic, or a combination of the two, and is applied in linear or rotary fashion. Drive power is applied during the larger central portion of each stroke, either mechanically or hydraulicly, and in either linear or rotary fashion, and the drive mechanism is then passive during the remaining, reversal portions of the stroke cycle.

Abstract: A hydraulic oil well pump drive system for driving an oil well sucker rod includes a master piston positioned within a master cylinder for axial displacement between first and second ends of the master cylinder. The master piston has a piston drive rod which extends through one end of the master cylinder. The drive rod is connected to a crank pin of an eccentric crank. A center seal assembly divides the master cylinder into a working chamber and a pressure chamber in opposite ends of the master cylinder. Each respective chamber defines a fluid volume which varies with the displacement of the master piston. The master piston displacement creates a bi-directional flow of working fluid from the working chamber. A wellhead hydraulic assembly is operably connected to the oil well sucker rod and is in fluid communication with the master cylinder working chamber to receive the working fluid flow.

Abstract: A double acting reciprocating intensifier uses a single low pressure fluid stream as both the power supply and the source of fluid the pressure of which is to be intensified. The entire device, including flow paths, is confined within a compact cylindrical housing. Tandem drive pistons minimize operating frequency, while maximizing intensification ratio and output volume flowrate. Placement of both high pressure cylinders downstream of the drive cylinders permits simple routing of flows through the centers of the low and high pressure pistons. A check valve connected between the high pressure pistons eliminates one of the four high pressure check valves required in the prior art. A single reciprocating valve, whose state is determined by drive and high pressure piston position, coordinates all of the drive side flows. Various components perform multiple functions to permit the compact shape.

Abstract: A well pumping system includes a pivotally mounted walking beam and "horsehead" connected to a downhole pump by a pump rod in the conventional manner. A hydraulic lift piston and cylinder and a pneumatic balance piston and cylinder are connected to the walking beam. A process control computer controls input signals to a hydraulic control valve for controlling the hydraulic cylinder rate and direction of travel to provide corresponding control over the motion of the walking beam. The computer receives input information from a position sensor indicating the displacement of the beam in its range of travel. The computer program also is responsive to a timer for determining actual stroke rate and acceleration of the beam. The computer monitors and controls operation of the hydraulics and pneumatics as the pumping unit produces the lift necessary to extract fluid from the well.

Abstract: An air-balance control system for a pumping unit minimizes the difference in torque on pumping unit components on the upstroke and the downstroke. The control system measures pump motor current and rod string position to effectuate porting air to or venting air from the air receiver tank in an air-balance system.

Abstract: The invention involves pressure-counterweighted oil-well pumping apparatus in which derrick structure of elemental simplicity involves components which are readily assembled and disassembled, such that a given pumping apparatus can be loaded on a single truck and transported from one to the next desired well-pumping location. For a given capacity pumping system, overall height requirements for the derrick structure are less than one half those of U.S. Pat. No. 4,631,918. And power-integrator complexity is substantially reduced by employment of a fixed-displacement variety in conjunction with a variable speed a-c motor as the prime mover, under control of solid-state devices and pressure-sensitive transducer elements which determine upper and lower limits of the reciprocating stroke.

Abstract: The invention contemplates hydraulic-lift mechanism which employs a power integrator in the connection between a charged hydraulic accumulator and the actuator for a vertically positionable load; the power integrator, additionally, has a prime-mover connection, and the pressurized charge of the accumulator is advisedly set to fully accommodate a preselected level of average load upon the actuator. The hydraulic circuit importantly includes check valves, with a pilot-operated check valve interposed between the power integrator and the accumulator and another pilot-operated check valve interposed between the power integrator and the load actuator. The pilot-operated check valves cooperate with other check valves to assure automatic transfer of hydraulic fluid under pressure from the accumulator to the load actuator, and vice versa, as may be determined by selected control of or via the power integrator.

Abstract: A battery-operated electric-motor driven hydraulic-lift mechanism for a fork-lift vehicle employs a hydraulic accumulator which serves an intertia-free counterweight function, designedly to the degree that such counterweight action is a direct offset of a predetermined average-load condition, as seen by the hydraulic-lift actuator of the system. Electric-motor drive is utilized for up/down operation of the fork lift, only to the extend needed to displace hydraulic fluid into or out of the "counterweighted" actuator. In some cases, such displacement will call for expending energy to add to or substract from the counterweight action; in other cases, the necessary fluid displacement results in an energy return to the system, i.e., in restoring energy to the battery.

Abstract: The invention contemplates hydraulic-lift mechanism which employs a power integrator in the connection between a charged hydraulic accumulator and the actuator for a vertically positionable load; the power integrator, additionally, has a prime-mover connection, and the pressurized charge of the accumulator is advisedly set to fully accommodate a preselected level of average load upon the actuator. The hydraulic circuit importantly includes check valves, with a pilot-operated check valve interposed between the power integrator and the accumulator and another pilot-operated check valve interposed between the power integrator and the load actuator. The pilot-operated check valves cooperate with other check valves to assure automatic transfer of hydraulic fluid under pressure from the accumulator to the load actuator, and vice versa, as may be determined by selected control of or via the power integrator.

Abstract: A pumping apparatus is disclosed which uses a reversible, variable displacement hydraulic drive pump capable of pumping fluid under pressure. A hydraulic cylinder enclosing a piston is operatively connected to a port of the hydraulic drive pump. A fluid accumulator, which is precharged to a selected precharge pressure, is operatively connected to the other port of the hydraulic drive pump. The fluid accumulator supplies the fluid under the precharge pressure to the hydraulic drive pump. The hydraulic drive pump increases the pressure on the fluid to a working pressure required to drive the piston from a first position in a first direction to a second predetermined position. Upon reaching the second position, the hydraulic drive pump reverses direction to reverse the flow of fluid from the hydraulic cylinder thereby reciprocating the piston back to its first position, and directing the fluid to the fluid accumulator.

Abstract: The invention contemplates a hydraulically operated twin-cable suspension for a clamshell or the like load-handling device. In a preferred embodiment, a charged accumulator is effectively a counterweight and is the source of all hydraulic fluid needed for the full range of actuation of two traction cylinders, one for each of the respective cables. Both cables automatically share the load, without slack, in any elevational situation, and simple hydraulic control circuitry selectively enables (a) an automated closing dig into loadable material and (b) a quick opening for load discharge. A single power integrator is interposed between the accumulator and the two traction cylinders for directionally controlling hydraulic-fluid displacement between the accumulator and the traction cylinders, as needed for all cable displacements.

Abstract: A pumping unit particularly for pumping oil from an oil bore has an inner stationary cylinder unit and an outer cylinder unit reciprocatable relative to the inner unit by hydraulic fluid; the units are enclosed in a casing and the outer unit functions as a piston in the casing; as the outer unit moves downwardly in the down-stroke, under the action of gravity and hydraulic fluid, air in the casing beneath it is displaced into a reservoir to form a supply of pressurized air; in the upstroke the supply of pressurized air is exploited to drive the outer cylinder upwardly, aided by the hydraulic fluid.

Abstract: The invention contemplates oil-well pumping apparatus (a) in which a traction cylinder is mounted at the well-head for direct reciprocating operation of the polish rod from which a pumping piston is suspended in a well casing, and (b) in which hydraulic-counterweight principles of copending application, Ser. No. 601,481, filed Apr. 18, 1984 are employed to reduce lift-capacity requirements which would otherwise be imposed on the prime mover.

Abstract: A hydraulic well pump for operating a pump sucker rod string including a hydraulic cylinder assembly for raising and lowering the sucker rod string and a fluid counterbalancing system for offsetting the combined weight of the reciprocating service equipment, the fluid column above the pump plunger, and the sucker rod string. One counterbalancing embodiment includes an air supported piston on the movable cylinder exposed to an air chamber below the air piston functioning independently of the hydraulic and power and logic system of the pump. Another counterbalancing system embodiment uses a hydraulic fluid accumulator connected into the system fluid power and logic for supercharging the hydraulic power pumps during the lift stroke and providing opposing force during the downstroke.

Abstract: A pumping apparatus includes a reversible variable displacement drive pump having two ports and a lifting apparatus connected to one of the ports. The lifting apparatus is designed to fit on the well-head of an oil well and attach to the polish rod of the well to operate a down-hole pump. A fluid accumulator containing a precharge is connected to the second port of the drive pump. A pump-off control system automatically adjusts the pumping rate of the lifting apparatus to the individual rate of formation flow of a particular well.

Abstract: A cylinder driving system comprising balance cylinders communicated to an accumlator for supporting a load under balanced state, a drive cylinder of a small diameter connected by way of a switching control device to an air source for driving the load with reduced air consumption and a speed controller provided either to the balance cylinders or to the drive cylinder for switching the load driving speed between high and low speeds.

Abstract: A pumping method, principally for oil, allows the sucker rod to fall under gravity for the first part of the downward stroke, then decelerates the sucker rod to a slow rate of descent, so creating a pause in the sucker rod's motion. Shock-absorbing means are provided to eliminate the impulsive loadings imposed upon the sucker rod at either extremity of its motion in conventional pumping methods. Hydraulically and mechanically-driven apparatus is disclosed for carrying out the method.

Abstract: An emergency shutdown system for an air-balanced pumping unit which includes a pump motor, a walking beam driven by the pump motor, a rod string reciprocated by the beam, and an air-balance cylinder and an air receiver which together define an air spring for storing energy from the beam is disclosed. A lever arm is pivotally mounted on the walking beam and attached at one end to the rod string so that a rotational moment is exerted in proportion to the weight of the rod string. Such rotational moment is opposed by an air bag, the output force of the air bag being adjustable within the expected range of the rotational moment. Thus, by properly adjusting the air bag, loss of load on the rod string results in movement of the lever arm. A shutdown valve is operatively connected to the lever arm and bleeds air from the air cylinder upon loss of load.

Abstract: A hydraulic actuator and system for driving a subsurface reciprocating pump. The actuator is double acting and comprises a piston reciprocable in a cylinder on a guide tube, so that the maximum volume of the chamber below the piston is greater than that of the chamber above the piston, and the lower working area of the piston is greater than its upper working area. Ports in the cylinder above and below the piston are connected to a valving and control arrangement, and a source and receiver of hydraulic fluid and an accummulator are also provided. The valving arrangement is controlled so that when the piston reaches a lower level of travel fluid is discharged from the upper chamber to the receive, to enable upward movement of the piston, and when the piston reaches an upper limit of travel discharge of fluid from the upper chamber is interrupted and flow of fluid from the lower chamber to the upper chamber and accummulator is enabled. Several valving and control arrangements are disclosed.

Abstract: The preferred embodiment is directed to an oil well pumping apparatus incorporating a walking beam having a horsehead at one end which connects to the sucker rods in the oil well. The opposite end of the walking beam is supported on a fixed pivot. A hydraulic and pneumatic combination unit connects from a supporting platform to a central point on the beam to raise and lower the beam. The improved apparatus utilizes air pressure to balance the static load on the apparatus and dynamically strokes the sucker rod string by imparting a reciprocating motion through hydraulic power applied at a specified rate to raise and lower the walking beam. A pump and motor system for a closed hydraulic loop is included. Alternate preferred embodiments are disclosed. In one form, a lubricating system is incorporated. First and second alternate forms of pickoff apparatus which powers the pneumatically balanced pumping apparatus is also included.

Abstract: A pumping method, principally for oil, allows the sucker rod to fall under gravity for the first part of the downward stroke, then decelerates the sucker rod to a slow rate of descent, so creating a pause in the sucker rod's motion. Shock-absorbing means are provided to eliminate the impulsive loadings imposed upon the sucker rod at either extremity of its motion in conventional pumping methods. Hydraulically and mechanically-driven apparatus is disclosed for carrying out the method.

Abstract: A hydraulic pump unit for pumping oil from oil-bearing strata which includes a frame slidably mounted on a stationary push-off tray and a hydraulic pumping unit mounted on the frame, which pumping unit further includes a pair of hydraulic cylinders supporting a head assembly. The head assembly is carried by a traveling mast slidably positioned in a vertically-oriented, stationary mast mounted on the frame, and includes a pair of rotatably-mounted chain rollers carrying a pair of chains attached to the stationary mast at one end and a bridle at the opposite end, which bridle also carries a polish rod extending into the well. Extension of the pistons in the hydraulic cylinders according to a selected hydraulic fluid flow control system causes the head assembly and traveling mast to move upwardly and the rollers to rotate with respect to the head assembly and extend the chains and polish rod upwardly to effect pumping of oil from the well.

Abstract: The present invention provides a hydraulic pumping unit, which is capable of pumping oil and other fluids from the downhole of a well. The pumping unit includes a frame and multi-cylinder system which is attached to the frame in such a manner that it is gravity centered. The bottom of the multi-cylinder system can be attached to the rod system of a well, and when the multi-cylinder system is expanded and contracted, the rod system and moving portion of the downhole pump of the well will be reciprocated back and forth, to bring (pump) oil or other fluid to the surface of the earth.Many other features and facets of the pumping unit are also disclosed.

Abstract: One pair of actuating piston and cylinder assemblies are operatively connected to the polish or sucker rod of the pump and are extended or retracted by hydraulic fluid. A further pair of piston and cylinder assemblies are operatively connected to the polish rod and are operatively connected on the underside thereof to an accumulator that includes an inert gas over oil with the gas being supplied under adjustable control conditions from a cylinder or source of high pressure gas so that these further pair of piston and cylinder assemblies counteract the weight of the pump system. On the downstroke, pressure is supplied to the upper sides of all four piston and cylinder assemblies with the two further piston and cylinder assemblies supporting the weight via the accumulator.

Abstract: A balanced hydraulic well pumping unit for actuating an underground pump in which the weight of the downstroke is utilized to store energy in an accumulator which is then used to assist in the upward stroke of the pump. A working rod passes through first and second vertically positioned cylinders and is connected to first and second pistons in the cylinders, respectively. Hydraulic power means are connected to the first cylinder for alternately supplying hydraulic fluid to opposite sides of the first piston for moving the working rod upwardly and downwardly. An accumulator is connected to opposite ends of the second cylinder whereby downward movement of the working rod causes the second piston to store energy in the accumulator which is then used to assist movement of the working rod upwardly on the upward stroke of the pumping unit. Preferably, the sucker rod of the well pump extends into the working rod thereby allowing the pumping unit to be positioned close to the well surface.

Abstract: A pumping unit for a well pump has a surface main cylinder with a main piston reciprocable therein, the piston having a connection to a standard well pump. In a flow cylinder of a relatively large diameter, a flow piston reciprocates within and divides the flow cylinder into a first flow chamber and a second flow chamber. The first flow chamber is in communication with the main cylinder. Air under pressure substantially to counterbalance the load on the well pump connection is supplied to the second flow chamber. There is a drive cylinder divided into a first drive chamber and a second drive chamber by a drive piston connected to but substantially smaller in diameter than the flow piston.

Abstract: A pumping jack for use with a well having a vertically reciprocable polish rod has a base including a horizontally extending table. A hydraulic cylinder is mounted on the base, with the cylinder axis extending parallel to and above the table. A plunger is reciprocable in the cylinder along the axis and carries with it a block including a first sheave around which a first flexible line is reeved. One end of the first line is affixed to the base, and the other end of the first line extends around a well sheave mounted on the base with the well sheave periphery tangent to the polish rod, the line from the well sheave being affixed to the polish rod. The reciprocating parts are balanced at least in part in either of two ways. In one way, there is a pneumatic chamber variable in volume in accordance with the reciprocation of the polymer and provided with air under an elevated pressure sufficient to counterbalance or offset part of the reciprocating load.

Abstract: A horizontally exposed pumping unit including a hollow base structure containing a volume of hydraulic fluid and compressed air, the base structure supporting a horizontally aligned reciprocating piston assembly deployed for horizontal translation along a support track formed thereon. The piston assembly terminates at the free end in a roller attached to the cylinder structure, the piston rod in turn being secured to yet another fixed roller. A sheave chain connected to the cylinder exterior passes around the rollers to be played out along the track, the chain being turned around the translating roller to a guide roller deployed above an oil well. The articulation of the piston assembly is achieved by way of an electrically driven hydraulic pump communicating between the hollow base structure and the cylinder. Two reversing switches are deployed within the track to change the direction of the hydraulic pump according to the stroke position of the piston assembly.

Abstract: A pump jack, such as the type capable of use in pumping crude oil from an oil well, the pump jack including a double acting piston and cylinder motor with the piston rod of the motor being adapted to be connected to the polished rod projecting upwardly from a well head. A variable displacement hydraulic pump, which is driven by a motor or engine, is included in a closed hydraulic loop wherein conduits are connected to a pair of output ports of the pump. A pump control means controls the direction and volume of flow in the loop so as to establish the stroke of the piston rod. A compressible fluid counterbalance is provided for accumulation of energy during a down stroke of the piston rod so that the energy may be returned to the piston during the up stroke. An economical and versatile unit may be produced by mounting a counterbalance cylinder coaxially above the motor and providing the counterbalance with an additional closed chamber in fluid communication with a charged chamber of the counterbalance.