This application discloses a reciprocating compressor including: a piston rod extending along a predetermined central axis that crosses an opening formed in an end of a cylinder, the piston rod being coupled to a piston and a crank mechanism to convey driving force from the crank mechanism to the piston; a rear head penetrated by the piston rod, the rear head closing the opening of the cylinder; and a rod ring portion configured to prevent a gas in the cylinder from leaking out from a gap between the rear head and the piston rod. The piston rod includes an outer circumferential surface on which an annular groove portion surrounding the central axis of the piston rod is formed. The rod ring portion includes an inner circumferential portion inserted into the groove portion, and an outer circumferential portion in sliding contact with an inner circumferential surface of the rear head.

A pump barrel (70) for use in a hydrostatic pump assembly includes a barrel body (88) defining a plurality of piston bores (84) that receive a plurality of pistons moveable within the bores, and a porting face (74) that defines a plurality of ports (72) in fluid communication with the piston bores and providing fluid flow paths into and out from the barrel body. Each port (72) has a leading edge surface and a trailing edge surface relative to a direction of rotation of the pump barrel, said leading and trailing edge surfaces being oriented in a first direction (along line 6-6) at non-right angles relative to the porting face (74). Each port (72) has an inner edge surface (80) and an outer edge surface (82) relative to a radial direction of the pump barrel, said inner and outer edge surfaces (80,82) being oriented in a second direction (along line 9-9) comprising a tilt angle (90,92) relative to the porting face (74) that is different from the angles in the first direction. A hydrostatic pump assembly incorporating such a pump barrel (70) is also disclosed.

A linear compressor is provided that may include a shell including a suction inlet, a cylinder provided in the shell to define a compression space for a refrigerant, a piston reciprocated in an axial direction within the cylinder, a discharge valve provided at a first side of the cylinder to selectively discharge the refrigerant compressed in the compression space, at least one nozzle, through which at least a portion of the refrigerant discharged through the discharge valve flows, the at least one nozzle being disposed in the cylinder, and at least one expansion portion that extends from the at least one nozzle to an inner circumferential surface of the cylinder, the at least one expansion portion having a flow cross-section area greater than a flow cross-section area of the at least one nozzle.

A hermetic compressor includes an electric motor element driving a compression element that includes a crankshaft including a main shaft, an eccentric shaft, and a flange, a cylinder block having a cylinder bore, and a piston configured to reciprocate in the cylinder bore. The crankshaft further includes a communicating oil supply passage provided in the flange, a main shaft oil supply passage, and an eccentric shaft oil supply passage.

A machine having one or more cylinders, each cylinder having an inner surface configured to engage a circumferential surface of a piston ring of a piston thereby defining a contact zone between the inner surface of the cylinder and the circumferential surface of the piston ring, the inner surface having at least one recess indented into the inner surface, wherein the ratio of the dimension of the recess in the direction of travel of the piston to the dimension of the contact zone in the direction of travel of the piston is in the range of approximately 1:5 to 3:5.

A fluid end block for attachment to a power end of a high pressure reciprocating pump includes a main body portion having an outwardly facing body forward face, an outwardly facing body rear face opposite the body forward face, and opposing side surfaces. A web portion protrudes outwardly from the outwardly facing body forward face. The web portion may have an outwardly facing web forward face and a curvilinear side surface. The web portion may be integral with the main body portion. A plurality of bosses protrude from the web forward face and having a forward facing end. The plurality of bosses may be integral with the main body portion and the web portion. A plunger bore extends through one of the plurality of bosses configured to receive a reciprocating plunger.

A flow restrictor is adapted for application in a bearing arrangement between a piston and a cylinder of a gas compressor. The compressor includes a protective block that involves the cylinder externally, and also includes at least one inner cavity, which is fluidly fed by a discharge flow resulting from a compression movement exerted by the piston inside the cylinder. The compressor includes a bearing-arrangement clearance that separates the piston and an inner wall of the cylinder. The compressor includes at least one flow restrictor provided with a housing that associates fluidly the inner cavity to the bearing-arrangement clearance. The flow restrictor is associated to the housing by a process of at least partial plastic deformation inside the housing, the flow restrictor being provided with channels for passage of fluid, the plastic deformation being sized for limiting the gas flow through the inner cavity to the bearing-arrangement clearance.

A manufacturing method for manufacturing a cylinder for a reciprocating compressor is disclosed. The method comprises the step of manufacturing a compressor barrel comprising a cylinder chamber, a first suction valve seat, fluidly coupled to the cylinder chamber through a respective first gas suction port; and a first delivery valve seat, fluidly coupled to the cylinder chamber through a respective first gas delivery port. The method further comprises the step of manufacturing a gas inlet plenum and further manufacturing a gas discharge plenum, separately from the compressor barrel.

Various embodiments include approaches for determining a top-dead-center (TDC) of a reciprocating compressor. In some cases, an apparatus includes: a pressure transducer configured to measure pressure fluctuations inside a compressor cylinder and convert the pressure fluctuations into an asynchronous waveform; and at least one computing device operably connected with the pressure transducer, the at least one computing device configured to: extract a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform; remove data representing invalid piston angles from the data set to form a refined data set; determine an average piston angle for the single revolution from the refined data set; and adjust the refined data set to identify a top-dead-center (TDC) position of the piston within the compressor cylinder.

A linear compressor according to an embodiment of the present invention comprises: a shell; a cylinder which is provided inside the shell and forms a compression space of a refrigerant; a frame which is coupled to the outer side of the cylinder; a piston which is provided so as to perform a reciprocating movement in an axial direction inside the cylinder; a motor which supplies power to the piston; and a spring mechanism which is coupled to the piston to allow the piston to perform a resonant movement, wherein the spring mechanism may comprise: a support which is connected to the piston and comprises a spring support unit having one or more insertion holes formed therein; a first coupling protrusion which extends from the rear side of the spring support unit along the edge of the insertion hole; a support cap which is inserted into the insertion hole and comprises a second coupling protrusion protruding from the front side of the spring support unit; a first resonant spring which is inserted into the outer circumferential surface of the second coupling protrusion; and a second resonant spring which is inserted into the outer circumferential surface of the first coupling protrusion.