Systems and methods for enhancing performance in a reciprocating compressor are described. The compressor includes a cylinder, a crank shaft housing, a crank shaft, a motor, a motor housing and rod assembly. The rod assembly includes a coupling rod portion, a head portion, a cup seal, a cap and one or more valves. The rod assembly is configured to reciprocate within the cylinder so as to compress fluid within a space formed by the cylinder. The rod assembly is driven by the crank shaft. The one or more valves are configured to control air to the compressor. The one or more valves are removably coupled to the head portion, such that the one or more valves remain coupled to the head portion when the cap is detached from the coupling rod assembly.

A reciprocating compressor may include a shell, a first cylinder, a plate, a second cylinder, and a piston. The first cylinder may be disposed within the shell and may include a first valve. The plate may be fixed relative to the first cylinder and may include a second valve. The second cylinder may be axially aligned with the first cylinder and may be moveable relative to the first cylinder between first and second positions. The piston may be disposed within the second cylinder and may include a third valve. The piston may reciprocate relative to the first and second cylinders. The piston and the plate may define a first compression chamber therebetween. The piston and the first cylinder may define a second compression chamber therebetween. A fluid-injection passage extending through the first cylinder selectively provides a working fluid from a source to the second compression chamber.

A double-headed piston type swash plate compressor includes a rotation shaft, a housing, a swash plate, two cylinder bores, a double-headed piston, and two shoes. The double-headed piston includes two shoe holders, a neck, two heads, and two coupling portions. Each of the coupling portions includes an outer portion and an inner portion. A direction orthogonal to both of an opposing direction of the inner portion and the outer portion and the axial direction of the double-headed piston is referred to as a widthwise direction. The inner portion includes a narrow portion and a wide portion. The wide portion projects out of the narrow portion in the widthwise direction and has a larger width than the narrow portion. An outer surface of the wide portion is slidable on a wall surface of the corresponding cylinder bore when the double-headed piston reciprocates in the cylinder bores.

A positive displacement pump includes at least two pumping chambers and associated plungers. Each plunger is driven by an associated variable speed motor, such as a stepper motor, in a reciprocating motion. The stepper motor varies speed during each stroke of the plunger. A controller controls speed and direction of each stepper motor. Each stepper motor is coupled to a leadscrew having an associated guide rod mounted on the leadscrew to move along the leadscrew as the leadscrew rotates and actuate an associated plunger. The controller varies the speed, displacement and duration of the stepper motors' steps to maintain a constant outflow without pulses.

A head assembly for a multi-cylinder compressor or pump having a first cylinder and a second cylinder includes a valve plate that has a first cylinder portion, a second cylinder portion, and a third portion positioned therebetween. The valve plate further including a valve plate face with a first aperture extending through the first cylinder portion and a second aperture extending through the second cylinder portion. The head assembly also includes a head cover having a head cover face, and at least one wall extending from one of the valve plate face and the head cover face to form a channel. The head cover being couplable to the valve plate such that the channel cooperates with the other of the valve plate face and the head cover face to form a chamber extending between and enclosing the first and second apertures of the valve plate.

A head assembly for a multi-cylinder compressor or pump having a first cylinder and a second cylinder includes a valve plate that has a first cylinder portion and a second cylinder portion. The valve plate further includes a valve plate face with a first aperture extending through the first cylinder portion and a second aperture extending through the second cylinder portion. The head assembly also includes a head cover having a head cover face, in which the head cover is operatively couplable to the valve plate. The head assembly further includes a first chamber formed by the valve plate cooperating with the head cover. The first chamber extends between and encloses the first and second apertures. The head assembly further includes a second chamber formed by the valve plate cooperating with the head cover. The second chamber is in fluid communication with the first chamber.

The present disclosure provides a variable-capacity compressor, a variable-capacity two-stage compression system and a control method thereof. The compression system includes a compressor, wherein the compressor includes a low pressure cylinder and a high pressure cylinder connected in series, wherein the low pressure cylinder comprises at least two cylinders connected in parallel. The compression system further comprises a control mechanism that can control at least one of the at least two cylinders connected in parallel to perform full-load and/or no-load operation.

An apparatus and method for sensing the position of a piston in a valve in a gas compressor or the position of a piston in a free piston engine. The apparatus includes a plurality of valve sensors, a plurality of magnets, and a plurality of valve sense modules coupled to the valve sensors and a controller coupled to the plurality of valve sense modules. The method includes processing information received from the valve sensors to determine the linear position of the valves in the gas compressor or a piston in a free piston engine.

A pump includes: a base with a through-hole flanked by an intake-hole and discharge-hole; an external cylinder fixed to the base; an end-fitting element disposed at external cylinder and having a through-hole; an internal cylinder inserted into the through-hole of end-fitting element and thereby partially received in external cylinder to fit coaxially inside external cylinder; a handle fixed to internal cylinder; a delivery pipe fixed to the base's through-hole and received coaxially in internal cylinder; an internal cylinder piston fixed to delivery pipe and received in internal cylinder; an external cylinder piston fixed to internal cylinder, received in external cylinder, and having a through-hole penetrated by delivery pipe; a check-valve disposed in intake-hole to ensure unidirectional gas movement therein; a discharge-valve disposed in discharge-hole; a control element for controlling discharge-valve to open and close; and a guide-channel communicating with the base's through-hole and intake-hole and connected to a nozzle.

An electromagnetic linear motor is described. It comprises a tubular stator (1) having a longitudinal axis (W); and a permanently magnet (7) with poles oriented along the axis and linearly movable along said axis inside the stator (1). The stator (1) comprises at least two columns (A, B) formed by electromagnets (2), each electromagnet (2) comprising a core (U) formed by a central straight segment (4) and two end polar expansions (5) all being oriented towards theand orthogonally tosaid axis (W), The columns are circularly arranged around said the permanent magnet (7), and mutually linearly offset along said axis.