A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a gas inlet on an outer circumferential surface and a supply port radially passing through the cylinder and communicating with the gas inlet. The gas inlet includes a first gas inlet and a second gas inlet disposed behind the first gas inlet, and the supply port includes a first supply port communicating with the first gas inlet and a second supply port disposed behind the first supply port and communicating with the second gas inlet. A flow rate passing through the first supply port is different from a flow rate passing through the second supply port.

A linear compressor includes a cylinder that defines a compression space of a refrigerant and has a cylindrical shape, and a piston disposed in the cylinder and reciprocating along an axis of the cylinder. The cylinder includes a gas inlet formed on an outer circumferential surface of the cylinder, a supply port radially passing through the cylinder and communicating with the gas inlet, and a recess communicating with the supply port and formed on an inner circumferential surface of the cylinder. An angle formed by an axial cross section of the recess and a straight line extending the supply port and an angle formed by the axial cross section of the recess and a straight line extending the inner circumferential surface of the cylinder each are an acute angle.

A method of actuating a double-action pump assembly with a reciprocating plunger includes signaling the reciprocating plunger to stop for a changeover period; while the pump is stopping, signaling the first inlet and outlet valves to close; while the first inlet and outlet valves are closing, signaling the second inlet and outlet valves to open, such that the second inlet and outlet valves begin to mechanically open at least a dwell period after the first inlet and outlet valves have entirely closed; and signaling the reciprocating plunger to begin moving while the second inlet and outlet valves are closing.

Provided is a linear compressor. The linear compressor includes a piston, a cylinder, and a bearing inflow passage. The bearing inflow passage includes a first bearing inflow passage extending inward from an outer circumferential surface of the cylinder in the radial direction and a second bearing inflow passage extending from the first bearing inflow passage to an inner circumferential surface of the cylinder. The second bearing inflow passage extends from the inner circumferential surface of the cylinder in a circumferential direction.

A reciprocating machine incltides a cylinder including an internal cylinder wail, a piston movable in the cylinder between a top position and a. bottom position, the piston, comprising an upper ring pack and a lower ring pack disposed around a circumference of the piston and spaced from each other by a first distance, and a circumferential collector groove in the cylinder wall in a position that is above the lower ring pack when the piston is in the top position and that is below the upper ring pack when the piston is in the bottom position, the collector groove including at least” one hole eonneciabie to a conduit for comieciion to a sump. A helical groove can also be provided in the cylinder wall.

A piston assembly for a piston pump includes an actuator rod, a piston coupled to the actuator rod and configured to contact a radially-inner wall of a cylinder, and an piston support structure coupled to the actuator rod and configured to contact the radially-inner wall of the cylinder. A fluid channel extends through the actuator rod and the piston support structure, and the fluid channel is configured to deliver a lubricating fluid to an annular space positioned between the piston and the piston support structure along an axial axis of the piston assembly.

A pumping system utilizes a linear actuator to move a shaft attached to two pistons within cylinders to pump a working fluid. A housing is designed with coolant passageways and one-way valves such that movement of the shaft also pumps coolant past cooling fins and over a motor. The shaft is formed of several sections joined by couplers which slide within a bore of the housing. The couplers have a non-round shape and the bore has a complimentary non-round cross section such that rotation of the shaft is prevented.

A linear compressor is provided. The linear compressor may include a cylinder that defines a compression space for a refrigerant; a piston that axially reciprocates inside the cylinder; a motor configured to provide a drive force to the piston; a discharge valve configured to discharge the refrigerant compressed in the compression space; and a discharge cover having a discharge space in which the refrigerant discharged through the discharge valve flows. The discharge valve and the discharge cover may be arranged inside the motor.

A linear compressor includes a cylinder that defines a compression chamber configured to accommodate refrigerant and that includes a cylinder nozzle configured to receive refrigerant, and a piston provided in the cylinder and configured to be pressed by refrigerant in the cylinder. The piston includes a piston body configured to move forward and backward within the cylinder, a piston front part located on a front surface of the piston body, the piston front part comprising a suction port through which refrigerant is supplied into the compression chamber, and a refrigerant collection part that is recessed from an outer circumferential surface of the piston front part, that extends to a front surface of the piston front part, and that is configured to receive at least a portion of refrigerant compressed in the compression chamber.

A linear compressor includes a compressor body configured to compress a refrigerant. The compressor body includes a cylinder, a discharge valve, a groove, a gas hole, and a flow restrictor. The cylinder receives a piston. The discharge valve is configured to open and close one side of the cylinder and define a compression space for the refrigerant together with the piston. The groove is defined in an outer circumferential surface of the cylinder and into which at least a portion of the refrigerant discharged through the discharge valve is introduced. The gas hole is defined in the groove to pass through the cylinder. The flow restrictor includes twisting wires made of different materials and is disposed to be wound around the groove.