Abstract: Reciprocating fluid pumps include a plunger configured to expand and compress in a reciprocating action to pump fluid, and one or more magnets carried by the plunger. The one or more magnets may be used to impart a force on the plunger when the plunger expands and compresses in the reciprocating action within a pump body responsive to a magnetic field. Shuttle valves for shifting flow of pressurized fluid between at least two conduits include a spool movable within a valve body and one or more magnets carried by the spool. The one or more magnets may be used to impart a force on the spool responsive to a magnetic field. Reciprocating fluid pumps may include such shuttle valves. Methods include forming and using such pumps and shuttle valves.

Abstract: The present invention discloses a mounting structure of a linear compressor, comprising: a shell which is a hermetic space, a connection terminal for supplying power being fixed to one side of the shell; a main body frame installed in the shell, one end of a cylinder forming a compression space for compressing a refrigerant with a piston being fixed to the main body frame; and a motor cover, a linear motor comprised of an inner stator, an outer stator and a mover, for reciprocating the piston by a mutual electromagnetic force being fixed to the outer circumference of the cylinder, the outer stator being bolt-fastened between the main body frame and the motor cover. Here, the main body frame is left-right symmetric.

Abstract: In one embodiment, a compressor includes a moving assembly configured to compress a gas within a compression volume; a guide rod connected to the moving assembly which reciprocates axially with the moving assembly; and a bellows seal positioned between the moving assembly and a stationary housing which at least partially defining the compression volume. In another embodiment, a compressor includes a motor assembly configured to compress a gas within a compression volume, the motor assembly including: a stationary coil assembly; a moving assembly having at least one magnet, and a gap located between the stationary coil assembly and the moving assembly; wherein the moving assembly is configured to reciprocate axially with respect to the stationary coil assembly when electrical current is applied to the stationary coil assembly, and to change the width of the gap between the stationary coil assembly and the moving assembly so as to provide magnetic axial stiffness against motion of the moving assembly.

Abstract: The present invention discloses a linear compressor which makes it possible to adjust a variable rate of a cooling capacity. The linear compressor includes a fixed member having a compression space therein, a movable member linearly reciprocated in the fixed member to compress a refrigerant sucked into the compression space, one or more springs provided to elastically support the movable member in the motion direction of the movable member, a motor unit including a motor connected to the movable member to linearly reciprocate the movable member in the axial direction and a capacitor connected in series to the motor, and a motor control unit controlling an AC voltage applied to the motor to adjust a variable rate of a cooling capacity by the reciprocation of the movable member.

Abstract: In at least some embodiments, an apparatus includes a hydraulic directional control manifold and a plurality of electric piezopumps. The apparatus also includes an electric piezopump controller that operates the plurality of electric piezopumps in varying combinations to provide generation and directional control of hydraulic power to linear hydraulic actuators using localized closed-loop hydraulic fluid.

Abstract: Driving arrangement (11) for a pump, compressor or similar, adapted to provide alternating pressure in at least two chambers (27a, 27b, 27?, 27?), such as chambers of a pump or compressor, as result of a reciprocating movement of a bar element (23). The bar element is connected to two movable pressure chamber faces being pistons (21a, 21 b) or plungers having fluid connection to said chambers, which bar element (23) is reciprocally supported in a housing (19). The driving arrangement further comprises an electric motor (31) which is adapted to provide the reciprocating movement of the bar element (23). The bar element extends through the rotor (31b) of the electric motor (31). The electric motor is an electric rotary motor. The invention also relates to a pump assembly with a plurality of such driving arrangements.

Abstract: A linear compressor is provided. The linear compressor may include a cylinder in which refrigerant flows in an axial direction, a piston that reciprocates within the cylinder so as to compress the refrigerant, and a linear motor that drives the piston. At least one of the cylinder or the piston may be sintering molded.

Abstract: Systems and methods including a motor or electromagnets to control the movement of one or more pistons in a pumping chamber. The pumping chamber may include a pump inlet and a pump outlet in fluid communication with the pumping chamber. Surfaces on a piston or pumping chamber may include hydrodynamic bearing surfaces.

Abstract: A reciprocatory fluid pump includes an armature assembly reciprocatably mounted in a housing and two leaf springs that are connected in parallel at two sides between the armature assembly and the base of the housing to constrain the reciprocations of the armature assembly to transverse displacements, enhancing the pumping efficiency and preventing friction during the reciprocating motion of the ferromagnetic member of the armature assembly, and therefore the reciprocatory fluid pump eliminates energy loss and generation of noises.

Abstract: A refrigerant circuit includes a linear electric compressor including a housing with a cylinder bore, a pair of end plates, a valve unit, a piston, an urging device for urging the piston, a coil generating electromagnetic force and a permanent magnet. The permanent magnet cooperates with the urging device and the coil to reciprocate the piston in the cylinder bore. The piston further includes a piston rod and the urging device is provided around the piston rod and a pair of piston heads integrally formed at opposite ends of the piston rod. The diameter of the piston rod is smaller than that of the piston head. The permanent magnet is provided on the piston head and the coil surrounds the piston head. The housing further includes a seat located between the pair of piston heads and the urging device is provided between the seat and each of the piston head.

Abstract: A gaseous fluid pump having at least one cylinder having a wall defining an inner volume and containing a central axis. First and second pistons that both move along the central axis, wherein the first piston and second piston have similar mass. The first and second pistons are propelled by magnetic forces in an oscillating motion with a 180 degree phase difference between the first and second pistons.

Abstract: Valveless piston pumps are disclosed that are magnetically driven, thereby eliminating a troublesome dynamic seal used on conventional valveless piston pumps. An exemplary embodiment includes a housing defining a bore having a bore axis. A piston is situated in the bore so as to be movable in the bore in a reciprocating manner along the bore axis and in a rotational manner about the bore axis. A magnet is situated in the bore and is coupled to the piston. The magnet is engageable magnetically with a magnet-driving device configured to cause the magnet, and thus the piston, to move in the reciprocating manner and in the rotational manner. An exemplary magnet-driving device is a stator assembly.

Abstract: A machine such as an external combustion engine in an electrical power and heat cogeneration unit comprises multiple cylinders, each driving an independent load or being independently driven, and a balance shaft comprising one or more off-centre balancing mass(es) to counteract rocking motion created by the piston motion and thereby assist in dynamically balancing the machine.

Abstract: A method of displacing a pumping assembly. In a first step, a first current is applied in a first direction through a coil assembly to displace a drive assembly from an initial position to cause a first pumping motion. Then, the drive assembly is returned to the initial position to cause a second pumping motion. At some point nearing the end of the second pumping motion, a second current is applied in the first direction through the coil assembly to decelerate the drive assembly before it reaches the initial position. A third current may be applied in a second direction through the coil assembly to cause or assist a return of the drive assembly to the initial position. An apparatus capable of carrying out the method is also disclosed.

Abstract: A nozzle device comprising a nozzle chamber includes a fluid inlet located at a first side of the nozzle chamber which is operative to introduce fluid into the nozzle chamber in an injection direction and a fluid outlet at a second side of the nozzle chamber which is operative to expel fluid from the nozzle chamber. A high frequency wave generator is also located in the nozzle chamber which is oriented and operative to generate high frequency waves in a direction which is substantially parallel to the injection direction, whereby to impart high frequency energy to the fluid in the nozzle chamber.

Abstract: A compressor capable of surely preventing leakage of a refrigerant gas from a connection portion between an airtight container and a pipe to the outside at low cost is provided. The compressor comprises an airtight container to which a refrigerant introduction pipe is connected, and a compression element received in the airtight container to discharge the refrigerant into the same. The refrigerant introduction pipe has a cylindrical pipe main body, and a jaw-like flange portion formed in a tip of the pipe main body. A cylindrical connection sleeve is disposed between the refrigerant introduction pipe and the airtight container. A first bolt is disposed to connect the connection sleeve to the airtight container, and a second bolt is disposed to connect the connection sleeve to the flange portion of the refrigerant introduction pipe. The flange portion of the refrigerant introduction pipe hides the first bolt.

Abstract: The invention relates to a reciprocating piston pump for delivering a liquid. The pump includes a solenoid with an actuator and an outlet port. A check valve with a seat body is assigned to the outlet port for keeping a return flow of the liquid out of the reciprocating piston pump. The seat body bears an impact damping face at a front face facing away from a valve seat of the check valve, and the valve seat of the check valve and the impact damping face are made from the same elastomer material.

Abstract: A linear drive device comprising at least one excitation winding for producing a variable magnetic field and is provided with an associated yoke body conducting a magnetic flux and an armature body which comprises a magnet carrier provided with at least two permanent magnet parts, preferably in the form of a plate, and to which an axial oscillation movement can be transferred by the magnetic field of the excitation winding. In order to avoid eddy currents in the magnet carrier, it is made of an electrically insulating material at least in the part thereof which penetrates into the magnetic field area defined by the pole surfaces of the yoke body and the excitation winding or which are arranged in said area. The magnet parts can be provided with ferromagnetic covers.

Abstract: A system for the metering and delivery of small discrete volumes of liquid is comprised of a small or minimal number of inexpensive components. One such component is a movable member, such as a miniature precision reciprocating displacement pump head, which is driven by an actuator that comprises a shape memory alloy material. The operating mechanism of the system is of little or minimal complexity. The system facilitates the precise metering and delivery of the small discrete volumes of liquid. Potential applications for the system include subcutaneous, long-term, automated drug delivery, for example, the delivery of insulin to a person with diabetes. In such an application, the small, simple and inexpensive nature of the invention would allow for its use as both a portable and a disposable system.

Abstract: A portable electromagnetic power system used as a remote alternate power source includes a water tank having an oil reservoir mounted on top of the tank with four cylinders extending through the tank and the two outer cylinders denoted the pressure cylinders and the two inner cylinders serving as accumulators with electromagnets mounted at the ends of each pressure cylinder for reciprocating an internal floating piston and each inner cylinder having a permanent magnet mounted at one end for actuating a magnetized floating piston disposed therein and each magnetized floating piston dividing the inner cylinder into an air chamber portion and a fluid chamber portion with the oil reservoir and the cylinders all in fluid flow registration with each other and the inner cylinders connected to a working pressure line that connects to a device, such as a hydraulic motor, so that the outer cylinder develop working pressure concomitant with the flow of oil therein that is directed to the inner (accumulator) cylinders fo

Abstract: The present invention discloses a mounting structure of a linear compressor, comprising: a shell which is a hermetic space, a connection terminal for supplying power being fixed to one side of the shell; a main body frame installed in the shell, one end of a cylinder forming a compression space for compressing a refrigerant with a piston being fixed to the main body frame; and a motor cover, a linear motor comprised of an inner stator, an outer stator and a mover, for reciprocating the piston by a mutual electromagnetic force being fixed to the outer circumference of the cylinder, the outer stator being bolt-fastened between the main body frame and the motor cover. Here, the main body frame is left-right symmetric.

Abstract: A compressor includes a cylinder and a piston moveable in an oscillating manner in the cylinder and having transverse play in relation to a movement direction. An end face of the piston delimits a compression chamber in the cylinder. A diameter of the piston reduces toward the end face.

Abstract: A system for the metering and delivery of small discrete volumes of liquid is comprised of a small or minimal number of inexpensive components. One such component is a movable member, such as a miniature precision reciprocating displacement pump head, which is driven by an actuator that comprises a shape memory alloy material. The operating mechanism of the system is of little or minimal complexity. The system facilitates the precise metering and delivery of the small discrete volumes of liquid. Potential applications for the system include subcutaneous, long-term, automated drug delivery, for example, the delivery of insulin to a person with diabetes. In such an application, the small, simple and inexpensive nature of the invention would allow for its use as both a portable and a disposable system.

Abstract: A compressor including a cylinder, the cylinder delimiting a compressor chamber having a circular cross-section and the cylinder having a longitudinal axis and including a front wall, the front wall of the cylinder having inlet and outlet openings for passage therethrough of a medium to be compressed; and a reciprocating piston disposed in the compressor chamber, the reciprocating piston being reciprocable within the compressor chamber in a movement that includes a dead center position and having a pair of opposed ends with one end being more proximate to the front wall of the cylinder than the other opposed end and the reciprocating piston having an expulsion projection on its one end, the expulsion projection entering the outlet opening in a dead center position of the reciprocating piston, the longitudinal axis of the cylinder extending through the outlet opening.

Abstract: A mover stabilizing and stator cooling arrangement includes an upper sleeve surrounding the mover of the linear motor, a lower sleeve, a thermoconducting sleeve surrounding the stator and axially connected between the upper sleeve and the lower sleeve, a thermal grease filled in the space defined between the upper sleeve and the mover and the space defined between the thermoconducting sleeve and the stator and the space defined between the lower sleeve and the outer tube for quick dissipation of waste heat, a stabilizer ring set between the upper sleeve and the mover to stabilize axial movement of the mover, and a piston and multiple one-way valve sets mounted in the space between the lower sleeve and the outer tube for allowing adjustment of the volume in the thermoconducting sleeve subject expansion/contraction of the thermal grease during temperature change.

Abstract: An apparatus having at least one of a linear drive having a stator and a rotor configured for reciprocating movement therein along a drive axis between a first and a second rotor reversal point about a rotor zero position, and a linear compressor, having a piston housing and a compressor piston configured for reciprocating movement therein along a piston axis between a first and a second piston reversal point about a piston zero position and configured to be driven by the linear drive, wherein at least one of the rotor zero position and the piston zero position is adjustable.

Abstract: A valve control system for a wellbore includes a fiber composite actuator functionally coupled to a valve operating member and means for controllably charging an interior of the actuator with fluid under pressure. A valve for a wellbore includes a valve stem and a valve seat associated with a valve body. The valve stem and valve seat are configured to enable fluid flow from an inlet port in the valve body to an outlet port in the valve body when the stem is moved from the seat. An axial contraction fiber composite actuator is functionally coupled to the valve stem. The valve includes means for controllably charging an interior of the actuator with fluid under pressure.

Abstract: The invention refers to a linear compressor, comprising: a shell (20); a cylinder (30) affixed to the shell (20) and defining a compression chamber (C); a piston (40) to be displaced in reciprocating movement in the interior of the compression chamber (C) during the operation of the compressor; a linear electric motor (50) mounted to the shell (20); and an actuating means (60) operatively coupling the piston (40) to the linear electric motor (50), in order to make the latter displace the piston (40) in a reciprocating movement in the interior of the compression chamber (C), the actuating means (60) being coupled to the piston (40) by an elastic means (70), so that the actuating means (60) and the piston (40) be displaced in phase opposition during the operation of the compressor.

Abstract: A high-efficiency magnetic reciprocating fluid device is provided. Magnetic pole members 10 and 12 having respective induction coils 16 and 18 fitted thereon are opposed to each other at the opposite sides of a magnetic armature 56 connected to one end of a piston that reciprocates in a cylinder. The magnetic armature 56 has an outer peripheral surface comprising arcuate side surfaces 56a designed to face mutually opposing surfaces 10a and 12a of the magnetic pole members 10 and 12 and plane surfaces 56b extending between the side surfaces 56a. Provision of the plane surfaces 56b makes it possible to increase the spacing between the side surfaces 56a, which face the magnetic pole members, without increasing the weight of the armature in comparison to a circular columnar magnetic armature and hence possible to increase the spacing between the magnetic pole members. Accordingly, induction coils reduced in copper loss by increasing the amount of copper used therefor can be fitted onto the magnetic pole members.

Abstract: An electrical linear motor for propelling a marine vessel comprises a thruster assembly disposed within a guide tube. Permanent magnets are attached to the thruster assembly and placed in close proximity to electrical coil windings, which are positioned outside of and parallel to the guide tube. Electrical current energizing the coil windings creates an electromagnetic field, which interacts with the magnetic field of the magnets to cause reciprocating linear motion of the thruster assembly with the guide tube. During the non-propelling back stroke, a check valve on the thruster assembly is in open position to allow free passage of water. The check valve is moved to a closed position during the working stroke of the thruster assembly, allowing the thruster assembly to propel the marine vessel.

Abstract: A reciprocating motor and a reciprocating compressor having the same are provided. One side of each of outer and inner cores forming a stator are connected to each other, to prevent a magnetic flux generated by the coil and a magnet from leaking out of the stator. Hence, it is possible to fabricate components of the reciprocating compressor employing such a reciprocating motor by using a relatively low-cost magnetic substance, resulting in a decrease in fabricating costs of the compressor. Also, a length of the magnet may be reduced, which results in a reduction of the cost for the magnet, thereby decreasing fabricating costs of the reciprocating motor and the reciprocating compressor employing the reciprocating motor.

Abstract: Disclosed is a structure for fixing a motor stator of a reciprocating compressor, the reciprocating compressor comprising: a frame unit mounted in a casing and elastically supported; a reciprocating motor including an outer stator coupled to the frame unit, an inner stator inserted into the outer stator, and a mover inserted between the outer stator and the inner stator; and a compression unit for compressing a refrigerant by receiving a linear-reciprocation driving force of the reciprocating motor, wherein the inner stator and the frame unit contacting the inner stator are coupled to each other by welding. According to this, the structure is simplified and a fabrication cost is reduced by facilitating a fabrication.

Abstract: The present invention discloses a controlling apparatus and method for a linear compressor which can provide an efficient control, by selectively performing an operation which is not affected by a capacitor and an operation which does not include a phase control according to a load. The controlling apparatus for the linear compressor includes an LC path (P1) composed of a coil winding portion (L) of the linear compressor and a capacitor (CP)1 a phase control path (P2) composed of the coil winding portion (L) and a phase control unit, and a switch means (62) for selectively applying power to one of the LC path (P1) and the phase control path (P2).

Abstract: A vibratory pumping machine including a pumping chamber disposed within a housing for the machine having an inlet tube that is insertable into a container having a liquid therein to withdraw the liquid from the container upon actuation of the pumping mechanism also located within the housing. The chamber includes an oscillating rod that engages a resilient outlet member to form a vacuum within the chamber which draws the liquid upwardly through the tube into the chamber for dispensing through the outlet member. A mechanism including the pumping chamber can be utilized to withdraw liquids from within container of various shapes and sizes, as well as to introduce other fluids, such as gases, into containers containing such liquids.

Abstract: A reciprocating compressor includes a reciprocating motor that generates a reciprocation force and a compressing unit to which a discharge pipe that discharges a compressed fluid is connected. The compressing unit compresses a fluid by receiving the reciprocation force generated by the reciprocating motor. A frame, to which the reciprocating motor and the compressing unit are fixed, is connected to a suction pipe that sucks a fluid to be compressed at one side thereof, and that contains lubricating oil therein.

Abstract: In a compressor, a motor includes a stator and a moving member that reciprocates. A frame supports the stator and a conductivity member flows at least a portion of magnetic flux flowing away from the stator back to the stator. Accordingly, the reciprocating compressor has enhanced energy efficiency.

Abstract: An object of the present invention is to provide a linear actuator in which reliability is improved, and performance is also easily improved. The present invention provides a linear actuator including a stator, a movable element having an iron member, and being reciprocatable with respect to the stator, a permanent magnet fixed to the stator so as to be opposed to the iron member, and a coil fixed to the stator. Because both the coil and the permanent magnet are fixed to the stator, electrical current does not have to be supplied to the movable element, and the feeder lines connected to the coil will not be broken due to the movement of the movable element. In addition, the weight of the movable element will not be increased even when the weigh of the permanent magnet is increased in order to obtain high magnetic flux density for improvement in performance. Moreover, because the movable element does not include a magnet, a magnetizing operation does not have to be applied to the movable element.

Abstract: A method of reducing or eliminating vibration in a linear reciprocating solenoid pump 10, the method comprising the steps of providing a solenoid pump 10 having a linear reciprocating plunger 14 and providing an electric circuit 48 to energize electro-motion means 16 of the solenoid pump 10, the electric circuit 48 energizing the electro-motion means 16 with an increased frequency of n times the frequency of normal mains electricity.

Abstract: The present invention discloses a linear compressor including a shell, a compressor main body installed in the shell and composed of a cylinder, a piston reciprocated inside the cylinder to compress refrigerant, and a linear motor for driving the piston, and elastic members spaced apart from the bottom of the shell to support the compressor main body inside the shell. In this configuration, since installation positions of the elastic members approach a gravity center of the compressor main body, a rotation moment imparted to the elastic members can be lowered and vibration of the compressor main body can be reduced.

Abstract: A pump for pumping one or more media comprises a housing (1) having an actuator chamber (2) and at least one pump chamber (4). The pump chamber (4) is provided with an inlet port and an outlet port. The pump chamber (4) is delimited by a displacement member (5) which is movable to and fro between a first position and a second position. The pump further comprises a movable actuator body (3), accommodated in the actuator chamber (2) and consisting of a magnetizable or magnetic material, for driving the displacement member (5). The pump also comprises magnetic drive means (8a, 8b) for creating a magnetic field in order to move the actuator body (3). The actuator body (3) is freely movable relative to the displacement member (5) so that the displacement member (5) can be moved, by means of an impact motion of the actuator body (3), from the first to the second position.

Abstract: An object of the present invention is to provide a linear actuator in which reliability is improved, and performance is also easily improved. The present invention provides a linear actuator including a stator, a movable element having an iron member, and being reciprocatable with respect to the stator, a permanent magnet fixed to the stator so as to be opposed to the iron member, and a coil fixed to the stator. Because both the coil and the permanent magnet are fixed to the stator, electrical current does not have to be supplied to the movable element, and the feeder lines connected to the coil will not be broken due to the movement of the movable element. In addition, the weight of the movable element will not be increased even when the weigh of the permanent magnet is increased in order to obtain high magnetic flux density for improvement in performance. Moreover, because the movable element does not include a magnet, a magnetizing operation does not have to be applied to the movable element.

Abstract: A metering pump device for a vehicle heater includes an inlet chamber, an outlet chamber, a first valve arrangement between the inlet chamber and the outlet chamber, which permits a fluid exchange substantially only from the inlet chamber to the outlet chamber, a displacement piston element, which in a first piston position minimizes the volume of the inlet chamber and in a second piston position minimizes the volume of the outlet chamber.

Abstract: An oil pumping unit is disclosed to include a motor, which has a mover that moves alternately up and down when the motor is electrically connected, and a pump, which has a barrel, an oil suction pipe mounted in the barrel, an inner sleeve, which is connected to the suction pipe and has installed therein a mixing valve, a movable valve and a piston, a bottom one-way oil intake valve, and a one-way mixing flow intake valve respectively arranged in such a manner that when the mover is operated to reciprocate the oil suction pipe, crude oil is alternately pumped through the one-way bottom oil intake valve and the one-way mixing flow intake valve to alternately pass through the movable valve and the mixing valve to the ground.

Abstract: A reciprocating compressor driven by a linear motor, comprising a shell, within which are mounted: a reference assembly formed by a motor and a cylinder (1); a resonant assembly formed by a piston (2) reciprocating inside the cylinder (1), and by an actuating means (3) operatively coupling the piston (2) to the motor; two spring means (10) mounted to the resonant assembly and to the reference assembly and which are elastically and axially deformed in the displacement direction of the piston (2); a mounting element (40) coupling an end of one spring means (10) to an end of the other spring means (10); and a coupling element (50) mounted to the piston (2) and to the mounting element (40), which is axially displaced together with the piston (2) and displaced freely and transversally to the displacement direction of the piston (2), said coupling element (50) transmitting the axial forces between the piston (2) and the mounting element (40) and minimizing the application of radial forces to the piston (2).

Abstract: A reciprocating pump includes a drive section and a pump section. The drive section has a reciprocating coil assembly to which alternating polarity control signals are applied by a reciprocating circuit during operation. A permanent magnet structure of the drive section creates a magnetic flux field which interacts with an electromagnetic field produced during application of the control signals to the coil. Depending upon the polarity of the control signals applied to the coil, the coil is driven in one of two directions of movement. The reciprocating circuit employs a storage capacitor and several switches to capture the energy of the reciprocating coil as the pump is driven downwardly. The charge is recycled as the capacitor dissipates, thereby reversing the polarity of the current through the coil and driving the coil assembly upwardly to its initial position.

Abstract: The present invention relates to a piston pumping system for substantially gas-free measurement and/or pumping of predetermined quantities of liquids, preferably pharmaceutical liquids containing oxidation-prone ingredients. Preferably, the system is used as a micropump or as a component thereof in medical devices such as transdermal therapeutic systems, for example.

Abstract: The solenoid is capable of generating great thrust and having broad-ranging thrust characteristics. The solenoid of the present invention comprises: a guide pipe formed into a cylindrical shape and provided inside of an excitation coil; a movable element having a small diameter section and a large diameter section; a first yoke part covering one end face of the excitation coil, the first yoke part having a first facing surface, which faces an outer circumferential face of the small diameter section of the movable element, and a second facing surface, which faces one end face of the small diameter section; and a second yoke part covering the other end face of the excitation coil, the second yoke part having a third facing surface, which faces an outer circumferential face of the large diameter section of the movable element, and a fourth facing surface, which faces one end face of the large diameter section.

Abstract: A reciprocating pump includes a drive section and a pump section. The drive section has a reciprocating coil assembly to which alternating polarity control signals are applied during operation. A permanent magnet structure of the drive section creates a magnetic flux field which interacts with an electromagnetic field produced during application of the control signals to the coil. The coil assembly includes a drive member that drives a plunger assembly having a plunger and a valve stem movably interfitted within the plunger and having a lower poppet head. As the plunger is driven downwardly the plunger contacts the poppet head to drive it into the pump chamber to force the fluid therefrom. There is a gap between the poppet head and the plunger so that the initial downward movement of the plunger closes the gap to gain momentum before it contacts the poppet head and drives it downwardly.

Abstract: Disclosed is a method of controlling drive speed of a motor operating in overload conditions. The method includes the steps of: driving the motor at a predetermined reference speed; detecting phase voltage and phase current applied to the motor; determining whether or not the motor is operating in overload conditions based on the detected phase voltage and phase current; and controlling the motor according to whether or not the motor is operating in overload conditions. Accordingly, the present invention can prevent occurrence of over-current due to the instantaneous acceleration of the motor to a predetermined initial speed.

Abstract: A reciprocating compressor with a linear motor having an actuating means operatively coupling a reciprocating piston to the motor; and a resonant spring means mounted under constant compression to the actuating means by the mutual seating of a pair of supporting surface portions, at least one of the latter being operatively associated with one of the spring means and the actuating means, against a respective pair of convex surface portions, each of the latter being operatively associated with the other of said parts, the convex surface portions being symmetrical and opposite in relation to the axis of cylinder, the supporting surface portions and the convex surface portions being mutually seated and operatively associated with the respective parts of the spring means and the actuating means, in order to transmit, by the mutually seated surface portions, the opposite axial forces with such intensity as to minimize the moments on the piston.