Abstract: A pump for use in low-profile applications comprises a barrel for holding fluid; and a piston that converts a rotational driving force into a longitudinal driving motion within the barrel. The pump provides space saving advantages by reducing the need for external equipment and mechanisms around the pump for providing actuation or moving the actuating mechanism.

Abstract: A pump includes a drive assembly having a drive shaft rotatable about a drive axis, and an eccentric coupled to the drive shaft for rotation therewith. The eccentric includes a shaft portion defining an eccentric axis that is offset from the drive axis. The shaft portion includes a shaft end defining a first alignment feature. A piston is rotatably coupled to the shaft portion and defines a second alignment feature. A cylinder reciprocatingly receives the piston. Positioning the first alignment feature in a predetermined orientation with respect to the second alignment feature locates the piston in one of a top-dead-center position and a bottom-dead-center position with respect to the cylinder.

Abstract: A sealed compressor (100) of the present invention comprises an electric component (111), a compression component (117), and a sealed container (101), the compression component includes a shaft (119), a cylinder block (129), a piston (133), and a crank weight (126), a rotor (115) of the electric component has a cylindrical shape, contains a cylindrical space therein, and includes an upper section (116) in which a lower portion of a bearing (131) of a cylinder block is fitted into the cylindrical space, a lower section (115e) to which a lower portion of the main shaft inserted into the through-hole of the bearing and inserted into the cylindrical space is fixedly fitted, and a balance weight (170, 270) placed on an opposite side of the crank weight with respect to the piston.

Abstract: A hermetic compressor includes a closed vessel for storing lubricating oil, an electric-driving element, and a compressing element driven by the electric-driving element. The compressing element includes a cylinder block forming a compression chamber, a piton that reciprocates inside the compression chamber, and an oiling device for supplying the lubricating oil to an outer circumference of the piston. A first oil groove is concavely formed on the outer circumference of the piston, and a second oil groove is concavely formed on a side opposite to the compression chamber relative to the first oil groove. The second oil groove has a spatial volume same or greater than that of the first oil groove. An expanded clearance portion is provided such that a clearance between the piston and the cylindrical hole portion broadens from a top dead point to a bottom dead point.

Abstract: A portable cooling unit comprising a magnetic spiral vapor pump that utilizes a magnetic pulse between two electromagnets and spiral drive slots to pull a piston back-and-forth 180-degrees and thereby alternately align compression slots on the piston's opposing ends with vapor suction ports and highly-compressed vapor discharge ports. Electromagnet use lowers the amount of battery power required for piston rotation. A condenser in a mounting pan under the pump achieves refrigerant condensation, while a fan blowing air through an evaporator positioned within a flexible hose causes cool air discharge through openings in the hose's terminal end fitting. The condenser utilizes surplus condensation from the evaporator to aid its vapor-to-liquid conversion, and batteries only provide power for the magnetic control module and fan.

Abstract: A modular paint pump for a paint roller having a battery operated pump in a housing supporting a paint can. A wetted parts subassembly is manually removable for cleaning or service without the use of tools. The wetted parts subassembly may include inlet and outlet check valves and a piston, a seal and a pump cylinder. A cover having a siphon is secured to the paint can by an elastic cord hooked to the housing.

Abstract: A refrigeration compressor includes a housing having a wall, a suction gases inlet and a compressed gases outlet. A linear compressor is supported for operation within the housing. A hollow tubular body extends from the compressed gases outlet and is adapted for attachment to a refrigerant circuit. A compressed gases discharge conduit extends from the linear compressor, and to the hollow tubular body to form a seal at a point of direct contact therewith.

Abstract: The invention relates to a domestic appliance, such as a steam iron or a coffee making apparatus. Such appliances comprising a housing, a water reservoir, an actuator, for example, plunger pump and a boiler for providing hot water or steam for an appliance. An input of the plunger pump is connected to the water reservoir, an output of the plunger pump is connected to an inlet of the boiler. In operation, the plunger pump is reciprocating at the mains frequency. The operating plunger pumps introduces vibrations which are transmitted to the housing and radiated by the housing to the environment which cause sounds and noise which are not user friendly.

Abstract: A precision pump system having a motor driver for accurately and repeatedly delivering process fluid, (e.g., photo chemicals) using a pumping fluid with minimal process fluid loss to a fabrication process and whereby the motor driver can be easily and quickly replaced without interrupting the fluid flow path. This is accomplished with the use of a process fluid reservoir and a pumping fluid reservoir that are associated with the pump, either integrated with the pump or closely adjacent. In addition, this precision pump system can be remotely monitored, viewed and controlled over the Internet. In addition, trapped process fluid within a downstream filtering block can be recirculated to the process fluid reservoir when trapped gas in the filter is removed. Furthermore, a nitrogen gas source is connected to the process fluid reservoir via a valve in case a need to insert a gas is required.

Abstract: A pump includes a substantially tubular housing having an inlet end and an outlet end and defining a central axis and a chamber within the body portion, and a movable valve assembly slidably received within the housing for movement in the direction of the central axis. The pump also includes a handle assembly slidably disposed at least partially around an outer circumference of the housing for movement in the direction of the central axis, the handle assembly being substantially annular ring-shaped, and the handle assembly including a grip engageable by a hand of an operator for manually sliding the handle assembly, the handle assembly being coupled to the movable valve assembly, manual movement of the handle assembly along the central axis causing corresponding movement on the movable valve assembly along the central axis.

Abstract: According to the invention, an air compressor includes: one pair of air tanks arranged parallel to each other by being separated from each other in a constant interval, for storing thereinto compressed air; a compressing unit that compresses air sucked from an external space so as to supply the compressed air to the air tanks; and a motor coupled to the compressing unit so as to drive the compressing unit, while the motor and the compressing unit are arranged above the one pair of air tanks; wherein: a cooling fan that generates cooling wind is provided on one end of a rotation shaft of the motor; and a control circuit unit that drives the motor is arranged above the one pair of air tanks and at a position which is overlapped with an axial direction projection area of the cooling fan.

Abstract: Disclosed is an oil-pumping machine, which is characterized in that it is composed of a secondary sheave (5) of a wheel-cylinder type driven by an electric motor.

Abstract: A hermetic compressor includes a closed vessel for storing lubricating oil, an electric-driving element, and a compressing element driven by the electric-driving element. The compressing element includes a cylinder block forming a compression chamber, a piton that reciprocates inside the compression chamber, and an oiling device for supplying the lubricating oil to an outer circumference of the piston. A first oil groove is concavely formed on the outer circumference of the piston, and a second oil groove is concavely formed on a side opposite to the compression chamber relative to the first oil groove. The second oil groove has a spatial volume same or greater than that of the first oil groove. An expanded clearance portion is provided such that a clearance between the piston and the cylindrical hole portion broadens from a top dead point to a bottom dead point.

Abstract: A pump system comprises an electric motor, a pump, a converter and a controller. The electric motor has a rotational output shaft that is rotatable in a first rotational direction and an opposite second rotational direction. The pump has a linearly displaceable input shaft that is movable in a first linear direction and an opposite second linear direction. The converter couples the output shaft to the input shaft such that rotation of the output shaft in the first rotational direction translates the input shaft in the first linear direction, and rotation of the output shaft in the second rotational direction translates the input shaft in the second linear direction. The controller repeatedly reverses rotation of the output shaft to produce reciprocating motion of the input shaft.

Abstract: Variations of the devices and methods disclosed herein pertain to an extended travel spiral flexure bearing having spiral arms, each of the spiral arms including an attachment point at the inner end thereof and at the outer end thereof. Variations of the bearing may also include a bearing clamp to be attached to the spiral flexure bearing at the attachment points, the bearing including an outer bearing portion to be disposed on the outer periphery of the flexure bearing and an inner bearing portion to be disposed at the center of the flexure bearing. Variations also pertain to a micro check valve assembly that includes a valve base, a valve cover, and a flexure that are all bonded together. The valve being closed when the valve door rests on the valve seat and open when the valve door is lifted from the valve seat.

Abstract: A hermetic compressor includes a closed vessel for storing lubricating oil, an electric-driving element, and a compressing element driven by the electric-driving element. The compressing element includes a cylinder block forming a compression chamber, a piton that reciprocates inside the compression chamber, and an oiling device for supplying the lubricating oil to an outer circumference of the piston. A first oil groove is concavely formed on the outer circumference of the piston, and a second oil groove is concavely formed on a side opposite to the compression chamber relative to the first oil groove. The second oil groove has a spatial volume same or greater than that of the first oil groove. An expanded clearance portion is provided such that a clearance between the piston and the cylindrical hole portion broadens from a top dead point to a bottom dead point.

Abstract: A compressor can have one or more of a suction fitting with integral louvers and a screen, a motor cap with a plurality of holes in the top surface of the motor cap to permit refrigerant to enter a suction plenum, a filter positioned over the plurality of holes in the motor cap, a filter for the cage bearing and a braze ring installed in one or more of the compressor fittings.

Abstract: A suction fitting for a compressor can include screens, filters, and direction control louvers to both filter out particulates and direct higher mass liquid refrigerant downward away from the inlet to the compression chamber. Alternatively, a mesh filter can be place over the opening(s) to the suction plenum to prevent debris and contaminants from entering the suction plenum.

Abstract: A motor cap has a plurality of holes in the top of the cap for the entry of refrigerant into the suction plenum. The holes are sized and located to create a tortuous path for a stream of refrigerant to enter the compression chamber. The refrigerant stream is broken into multiple streams and any liquid refrigerant is encouraged to flash to vapor. Any oil that is brought from the sump at startup by boiling liquid refrigerant is likewise encouraged to remain on the motor cap and drain back to the sump while the liquid refrigerant flashes to vapor.

Abstract: A valve device of a compressor of the present invention comprises a plate (17), a reed (21, 75), and a stopper (31), wherein the reed includes: an opening/closing section (60, 70), a fastened section (61, 71); and a joining section (62, 72), the opening/closing section, the fastened section and the joining section being arranged in a direction in which a symmetric axis extends; wherein in a portion of the joining section which is closer to the opening/closing section, a pair of portions (102, 112, 82, 86) of an outer periphery of each of one or two openings (63, 65, 73, 77) which are closest to both ends of the joining section are symmetric with respect to the symmetric axis so as to form a substantially-V-shape or substantially-U-shape, in a direction from the opening/closing section toward the fastened section; and in a portion of the joining section which is closer to the fastened section, a pair of portions (103, 113, 83, 87) of the outer periphery of each of one or two openings which are closest to the b

Abstract: Pump device for hydraulically activating a valve in particular used for oil and gas exploration wherein such a valve may be a safety valve assigned to a riser or a tree, said pump device including a piston cylinder unit from which pressurized hydraulic fluid can be pumped in direction to the valve. To improve such a pump device so that the pressure of the hydraulic fluid is produced in particular at the corresponding site and near to the valve and is safe and constructed in a simple way an electrical drive means is movably connected to a piston of the piston cylinder unit for alternating movement in axial direction of the piston within the cylinder.

Abstract: An air pump structured to facilitate the installation of a pair of pistons includes a casing (17) having a pair of cylinder chambers (14) slidably accommodating a pair of pistons (16), respectively, and a drive chamber accommodating electromagnets between the pair of cylinder chambers. The pump casing has mutually opposing side walls and a cylindrical peripheral wall defining the drive chamber. The side walls have circular cylindrical inner peripheral surfaces (28-1) of the cylinders defined therein, respectively. A piston assembly having the pistons connected to the opposite ends of an armature (34) is inserted into the pump casing through one of the cylindrical inner peripheral surfaces and installed therein. The peripheral wall has an electromagnet-loading opening (26-2) through which electromagnet pedestal members (26-7) and the electromagnets are inserted into the casing and secured therein.

Abstract: A closed type compressor of a low overall height and small vibrations provided with a structure comprising a balancing weight (142) formed of a first balancing weight (146) and a second balancing weight (148) and fixed to eccentric shaft portion (112), the first balancing weight (146) located closer to a main shaft portion (109) than the second balancing weight (148), and the second balancing weight (148) jutting out to a position further from an axis of the eccentric shaft portion (112) than the first balancing weight (146).

Abstract: A sealed compressor of the present invention comprises an electric component (105); a compression component (107); and a sealed container (101) accommodating the electric component (105) and the compression component (107); wherein the compression component (107) includes: a cylinder block (115) defining a compression chamber (135); a piston (125); and a valve plate (133) having a suction hole (137) through which a refrigerant gas to be compressed in the interior of the compression chamber (135) flows, and a discharge hole (139) through which the refrigerant gas compressed in the interior of the compression chamber 8135) is discharged; wherein the piston (125) is provided with a projection (155) on a tip end surface (153) which faces the valve plate (133); and wherein the projection (155) is configured such that side surfaces thereof include at least one flat surface and a gradient ? of the flat surface with respect to the tip end surface of the piston (125) is smaller than a gradient ? of another side surfac

Abstract: A linear drive, in particular for a piston pump, includes a first electromagnetic drive device, a second electromagnetic drive device, and a drive piston configured to be moved in an axial direction by the drive devices. The first drive device and the second drive device are each in the form of a reluctance drive device. The reluctance drive devices each have a stator with a stator coil that engages around the drive piston in a circumferential direction. The reluctance drive devices each also have a coil core with a coil receptacle, open in a radial direction toward the drive piston, for the coil winding. A piston pump arrangement includes the linear drive.

Abstract: A crank-type non-beam pumping unit, including a belt, a foundation, a crown sheave, a frame, a support rod, a belt pulley, a pin shaft, a crank, a transmission shaft, and a bracket. The bottom of the frame is disposed on the foundation, and the top of the frame is supported by the support rod. The top of the support rod is hinge connected to the frame, and the bottom of the support rod is hinge connected to the foundation. The bracket is disposed on the foundation, the transmission shaft is disposed on the bracket, and the crank is disposed on the transmission shaft. The crank rotates synchronously with the transmission shaft, and the belt pulley is disposed on one end of the crank via the pin shaft. One end of the belt bypasses the crown sheave, and is connected to a smooth sucker rod.

Abstract: An air compressor includes a cylinder housing, an outlet receptacle disposed on the cylinder housing, and a partition formed between the cylinder housing and the outlet receptacle and having an air passage formed in the partition, a piston slidably received in the cylinder housing and coupled to a motor for moving relative to the cylinder housing in a reciprocating action in order to generate a pressurized air, and a spring-biased check valve engaged with the partition for selectively blocking the air passage of the partition, the outlet receptacle includes an inner diameter “D2” no less than an inner diameter “D1” of the cylinder housing for allowing the pressurized air to easily flow into the outlet receptacle and for allowing the piston to be moved in a greater moving speed.

Abstract: A hermetic compressor is provided that is capable of supplying oil even in a low-speed operation. The hermetic compressor includes a hermetic container filled with oil in a base thereof, a rotatably crank shaft having a screw-shaped oil groove in an outer portion thereof, and an oil feeder having an upper portion in which a lower portion of the crank shaft is inserted, the oil feeder having a lower portion immersed in the oil of the hermetic container.

Abstract: A variable capacity compressor assembly (20) configured for variable capacity modulation includes a housing (30), with a compressing mechanism (22) and a driving mechanism (24) disposed within the housing. The compressing mechanism includes compressing members (54, 56) that are shiftable relative to one another between loaded and unloaded states. The driving mechanism includes a line-start brushless permanent magnet motor (26). The line-start brushless permanent magnet motor includes a plurality of permanent magnets (102) that are mounted on, and extend generally axially along, a rotor core body (90) of the motor. Using the motor may reduce manufacture cost, maintain conveniently, and increase reliability.

Abstract: A piston type compressor wherein the position of the piston highest pressure point is indicated and the rotor of the motor at the optimal starting angle aligned prior to the actual compression operation by providing a pre-pulse to rotate the rotor of the motor at least one full rotation at a certain frequency, during rotation measuring the load torque by the frequency converter as well as indicating the maximum load torque point and at the end aligning the rotor of the motor at the optimal starting angle of about 180° from the maximum pressure angle, and at the beginning of the actual compression operation setting the rotor position opposite to the maximum torque angle by feeding direct current to the stator winding and starting the motor by supplying maximum motor current to the motor to give the maximum torque and acceleration.

Abstract: A reciprocating piston compressor for use in a refrigerant compression circuit comprises first and second intake manifolds, first and second reciprocating piston compression units, an outlet manifold and a first pulsing valve. The intake manifolds segregate inlet flow into the compressor. The first and second reciprocating piston compression units receive flow from the first and second intake manifolds, respectively. The outlet manifold collects and distributes compressed refrigerant from the compression units. The first pulsing valve is mounted externally of the first intake manifold to regulate refrigerant flow into the first intake manifold. In another embodiment, a second valve is mounted externally of the second intake manifold to regulate flow into the second intake manifold, and the first and second valves are operated by a controller. The controller activates the first valve with variable width pulses having intervals less than an operating inertia of the refrigerant compression circuit.

Abstract: An improved method is provided, for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, through use of a cranked rod pumping (CRP) apparatus for imparting reciprocating substantially vertical motion to a rod of a sucker-rod pump having a pump stroke. The CRP apparatus includes a motor driven cranked mechanical actuator arrangement. The cranked mechanical actuator arrangement includes a substantially vertically moveable member attached to the rod of the sucker-rod pump for imparting and controlling vertical motion of the rod of the sucker-rod pump. The actuator arrangement may include pneumatic counterbalancing.

Abstract: A hermetic compressor includes a thrust ball bearing (176) on the thrust face (160) of the main bearing (126). The thrust ball bearing (176) includes balls (166) held in a holder (168), an upper race (164) and a lower race (170) arranged respectively on and beneath the balls (166), and an elastic support member (172) below the balls (166). The hermetic compressor is prevented from causing a load to be applied unevenly to the balls (166), thereby achieving high efficiency, low noise level, and high reliability.

Abstract: A plunger pump includes a housing with a discharge valve in communication with an outlet. The housing includes a bore that slidably accommodates a plunger. The housing also includes an inlet. The plunger has a closed proximal end connected to an actuator and a distal end with an outlet valve. The plunger also includes a sidewall with an opening that is in communication with the inlet of the housing. Fluid flows through the inlet and through the opening and into the plunger. When the plunger is retracted away from the discharge valve, the outlet valve of the plunger opens thereby providing fluid for the housing bore. As the plunger is moved towards the discharge valve, pressure in the housing bore increases thereby opening the discharge valve and permitting the pressurized fluid to exit through the outlet.

Abstract: An air pump positioned within a hollow space in an aerodynamic structure for controlling the flow over an aerodynamic surface thereof, includes a movable member linearly displaced by a very low friction piston mechanism and a compression chamber open to the exterior of the aerodynamic surface through an orifice. Reciprocal displacement of the very low friction movable member changes the volume of the compression chamber to alternately expel fluid (e.g., air) from and pull fluid into the compression chamber through the orifice. The movable member includes a piston oscillating within a piston housing each having an ultra-low friction coating for improved thermal performance and reduced maintenance. Fluid intake to the compression chamber may be increased through the use of a one-way valve located either in the aerodynamic surface, or in the piston. Multiple flapper valves may surround the orifice in the aerodynamic surface for increased fluid control.

Abstract: A pump assembly for use in a selective catalytic reduction system, the pump assembly comprising: a pump sub-assembly defining a pump axis; and a housing sub-assembly including a cavity for receiving the pump sub-assembly and comprising an inlet port for receiving a reagent for supply to the pump sub-assembly via a flow path; wherein at least one seal member is provided to seal the pump sub-assembly within the housing sub-assembly, the seal member being provided in a groove in an outer face of the pump sub-assembly, the seal member providing a fluid tight seal.

Abstract: A surface motor direct-drive sucker-rod screw pump device is driven by a vertical three-phase permanent magnet brush-less DC motor, and comprises a motor controller (6), a rectifying circuit, an inversion circuit, a CPU and a driving circuit. The motor controller (6) is used to adjust the voltage and frequency of the motor by the rectifying circuit, the inversion circuit, the CPU and the driving circuit. Thus, the speed of the motor can vary from zero to the maximum. The device is easy to operate and has a higher efficiency.

Abstract: A linear pump and motor system includes a motor, rotary-to-linear mechanism, pressure compensation device (PCD), and gas mitigation assembly. The rotary-to-linear mechanism may translate rotation of a motor into linear motion to provide a pumping action. A PCD may minimize a pressure differential between lubrication fluids and external fluids. A gas mitigation assembly may provide a mechanism that mechanically opens a valve. In some embodiments, a PCD may be utilized separately from the linear pump. In some embodiments, a gas mitigation assembly may be utilized separately from the linear pump.

Abstract: A reciprocating compressor is provided that may include an outer stator; an inner stator provided at an inner side of the outer stator with a predetermined gap therebetween; a mover configured to perform a reciprocating movement in the gap between the outer stator and the inner stator; a piston coupled to the mover to perform a reciprocating movement therewith; a cylinder, into which the piston may be inserted to form a compression space while performing a reciprocating movement; a frame coupled to the cylinder; a first support member coupled to the outer stator and the frame; and a second support member separated from the first support member, but coupled to the inner stator and the frame, thereby facilitating concentricity of the motor and compressor device, as well as simplifying an assembly process as the motor and compressor device are divided into several blocks for assembly.

Abstract: A hydrostatic actuator and an arrangement for attaching it to a receiving component are provided. The hydrostatic actuator has a master cylinder containing a housing and a piston movable axially within the housing which acts on a pressure chamber filled with a pressurizing agent. The piston is driven by a rotary-driven electric motor having a stator and a rotor, by a rolling planetary transmission that converts the rotary drive to an axial motion. In order to be able to produce such a hydrostatic actuator with little need for construction space, cost-effectively and with better quality, a supporting of the rolling planetary transmission is simplified, and the cooling and shielding of an electronic controller and the pressure behavior of the hydrostatic actuator is improved.

Abstract: An electromagnetic pump configured with an electromagnetic portion that generates an electromagnetic force for pressing the piston, and an urging member that urges the piston in a direction opposite to the electromagnetic force. A strainer member including a disk-shaped portion which has a disk shape and in which a strainer surface is formed, and a side portion that extends from an outer peripheral edge of the disk-shaped portion. A suction check valve being capable of sucking the working fluid via the strainer surface. The piston, the urging member, the suction check valve, and the strainer member are sequentially inserted into the cylinder from a side opposite to the electromagnetic portion, and the cover member is attached so as to press the strainer surface.

Abstract: An electromagnetic pump including a piston, an electromagnetic portion that moves the piston forward, and a spring that moves the piston backward. The piston including a discharge check valve built in the piston. The piston is formed with a hollow portion that opens in an inner peripheral portion of an end surface of the piston, and a spring receiving surface formed on an outer peripheral portion of the end surface to receive the spring. The discharge check valve is fixed through plastic deformation of the piston by inserting the discharge check valve into the hollow portion from an opening of the piston, and partially pressing a portion of the spring receiving surface of the piston on an inner peripheral side after the insertion to recess the spring receiving surface and elevate an inner peripheral surface of the piston surrounding the hollow portion.

Abstract: A linear compressor has a hollow piston with crown and sidewall. The piston reciprocates in a cylinder. A piston rod connects the piston to a spring. A connection between the piston rod and the piston transmits axial forces directly to the piston crown. The connection transmits lateral forces to the piston at an axial location away from the piston crown. The connection allows rotational flexibility between the piston and the piston rod transverse to and uniformly around the piston reciprocation axis. Other improvements in or relating to linear compressors are disclosed and claimed.

Abstract: A linear compressor is provided. Unnecessary parts of a motor cover of the compressor are bent toward a rear cover in an axis direction to form supporting ends of the motor cover, and the supporting ends of the motor cover are welded directly to the rear cover, thereby considerably cutting down the material cost.

Abstract: A refrigeration compressor includes a housing having a suction gases inlet and a compressed gases outlet. A linear compressor is supported for operation within the housing. A compressed gases discharge conduit extends from the linear compressor to the housing to connect with the outlet. The conduit is formed of a material of lower heat conductivity than the housing. The conduit passes through the wall of the housing at the compressed gases outlet.

Abstract: A linear compressor is provided. The linear compressor includes an electro-magnetic spring and a casing that defines a chamber. A piston is received within the chamber of the casing. The electro-magnetic spring can apply a non-linear force to the piston such that a total spring force applied to the piston during a compression stroke is substantially linear.

Abstract: A linear compressor is provided. The linear compressor includes a casing that defines a chamber and a piston slidably received within the chamber of the casing. A driving coil is configured for selectively urging the piston to slide within the chamber of the casing. An electro-magnetic spring is configured for urging the piston towards a default position when the piston is positioned away from the default position. The electro-magnetic spring can permit the linear compressor to operate at a resonant condition.

Abstract: An apparatus and method for pumping fluids, such as water and/or hydrocarbons, from a subterranean formation or reservoir, include a linear rod pump having a mechanical rack and pinion drive arrangement, adapted for attachment to a pumping mechanism, such as the polished rod at the top of a rod string in a hydrocarbon well. The rack gear, of the rack and pinion drive arrangement, is adapted for connection to a cable and pulley arrangement for imparting motion to the polished rod. The pinion gear does not translate with the rack gear, and is driven by a reversible motor for affecting up and down reciprocating motion of the rack gear and pumping mechanism. Some forms of the invention include a compressible gas counter-balance arrangement. Some forms of the invention include an electronic drive configured for dealing with electric power generated by the motor during a portion of the pumping cycle.

Abstract: A fluid end 15 for a multiple reciprocating pump assembly 12 comprises at least three plunger bores 61 or 91, each for receiving a reciprocating plunger 35. Each plunger bore has a plunger bore axis 65 or 95. The plunger bores are arranged across the fluid end to define a central plunger bore with lateral plunger bores located on either side. The fluid end 15 also comprises at least three respective suction valve bores 59 or 89 in fluid communication with the plunger bores. Each suction valve bore can receive a suction valve 41 and has a suction valve bore axis 63 or 93. The fluid end 15 also comprises at least three respective discharge valve bores 57 or 87 that can receive a discharge valve 43 and are in fluid communication with the plunger bores. Axes of suction and discharge valve bores are offset in the fluid.

Abstract: A fluid end (15) for a multiple reciprocating pump assembly (12) comprises at least three plunger bores (61 or 91) each for receiving a reciprocating plunger (35), each plunger bore having a plunger bore axis (65 or 95). Plunger bores being arranged across the fluid head to define a central plunger bore and lateral plunger bores located on either side of the central plunger bore. Fluid end (15) has suction valve bores (59 or 89), each suction valve bore receiving a suction valve (41) and having a suction valve bore axis (63 or 93). Discharge valve bores (57 or 87), each discharge valve bore receiving a discharge valve (43) and having a discharge valve bore axis (63 or 93). The axes of at least one of suction and discharge valve bores is inwardly offset in the fluid end from its respective plunger bore axis.