Abstract: A natural gas pumping system that includes six reciprocating compressor cylinders, the reciprocating pistons of the six compressors having cycles offset by 60 degrees one from another.

Abstract: A piston includes a piston body which is surrounded by a media side, by an oppositely disposed drive side and, at the peripheral side, by a piston jacket, wherein the piston jacket forms a connection between the media side and the drive side. The piston jacket is arranged about a piston axis, wherein the piston jacket is connected to the piston body via a web element so that a peripheral groove is formed on the media side between the piston body and the piston jacket. A cover element is arranged at the media side, and has a drive side surface which lies directly on the media side surface of the piston body.

Abstract: A hydraulic accumulator for use in a drill string having a fluid passage for supply of fluid to a hydraulic drill string tool is provided. The accumulator comprises a body provided with connecting means for connecting the accumulator to the drill string and an expansion chamber in fluid communication the fluid passage when the accumulator is connected to the drill string by the connecting means. The expansion chamber is expandable between a first volume and a second volume which is larger than the first volume. Further, the expansion chamber is provided with means for moving the expansion chamber from the first to the second volume upon a fluid pressure increase in the fluid passage and for moving the expansion chamber from the second to the first volume upon a pressure decrease in the fluid passage.

Abstract: A unitary, “hollow out” piston is molded or forged with only two tools, which move along a single parting direction, with a pair of arcuate side walls that provide maximal outer surface area with minimal thickness and weight. The thin walls are internally fortified by a cruciform support structure that is molded integrally by the same tools. No post forming machining steps are needed to reduce weight.

Abstract: The invention can prevent gas leakage and reduce friction force while relaxing tolerance for manufacturing a displacer and the like for Stirling cycle machines. Gas leakage between the outer periphery of a seal (1) and the inner peripheral surface (5a) of a cylinder (5) is prevented. Accordingly, precise finish of the radial clearance between the displacer (2) and the cylinder (5) is not required. As the difference of pressures between the front and rear spaces of the displacer (2) is small, the gas leakage is sufficiently prevented without pressing the seal (1) against the inner peripheral surface (5a) of the cylinder (5). On the other hand, as the friction force generated between them is significantly small, it does not affect the reciprocation of the displacer. As the seal (1) is provided so as not to be restricted axially and radially, the displacer is kept closely contacted with the inner peripheral surface (5a) of the cylinder (5) even if the displacer (2) eccentrically shifts.

Abstract: A piston unit (10) comprises a piston (10a) and a connecting element (5). The piston comprises a piston head (1) comprising a compression surface (1a1) and a skirt portion. The skirt portion comprises a first and second ring (2, 3) apart form each other in the axial direction. The first and second rings (2, 3) are jointed to each other by jointing members (4a) at angularly-spaced positions with widows being left between the first and the second rings (2, 3). The piston head (1) is made of resin and is fixedly mounted at an axial end of the first ring and the connecting element (5) is fixed to the opposite axial end of the second ring (3). The connecting element (5) comprises four plates (5b, 5c) combined to form a cross in cross section. The four plates (5b, 5c) connect the axial end of the second ring (3) at angularly-spaced positions.

Abstract: A compressor having a cylinder bores and pistons are disclosed. Each piston moves in the associated cylinder to compress gas therein. Each piston slides on an inner peripheral wall of an associated cylinder to seal a compression chamber. Each piston includes an outer peripheral surface and cavities. The outer peripheral surface has a seal to seal the cylinder and a pressure receiving surface to receive reaction forces from the wall of the cylinder. A low friction layer is formed on the pressure receiving surface. The layer facilitates the sliding movement of the piston with respect to the cylinder.

Abstract: A piston for a fluid-actuated, percussive, down-the-hole drill is provided with self-lubricating bearings and self-lubricating seals. The piston includes an elongated body member terminating in a front end and a back end and having a longitudinal bore therethrough. A bearing and seal combination is positioned adjacent each end of the piston and an undercut portion of the piston body extends therebetween. The bore and undercut portions of the body form a portion of fluid passageways in the drill, when the piston is reciprocated in the drill. The seals float in their grooves, being movable axially, radially and circumferentially. The bearings are substantially nonmovable axially and radially.

Abstract: A hollow through-bolt is threaded internally and externally, at one end, to receive therein a reciprocable, end-threaded rod. A pair of fluid-control valves, centrally bored, are mounted on the through-bolt in spaced apart disposition. The other end of the through-bolt has a shoulder formed thereon for seating one of the valves thereagainst, and the other valve central bore is tapped for threaded engagement with the one end of the through-bolt. A sleeve, slidably engaged with the through-bolt, and interposed between the valves, maintains the one valve positioned against the shoulder.

Abstract: In a pyrotechnic linear piston and cylinder drive in a belt pretensioner, the cylinder (10) has a frustoconical free end (12) and the piston (14) is attached to the end of a cable (16). The piston (14) is tapered frustoconically at its end adjacent to the free end (12) of the cylinder (10). An annular piston member (22) is slipped over and frictionally engaged with the tapered end portion (20) of the piston (14). When the annular piston member (22) reaches the frustoconical free end (12) of the cylinder (10), the piston (14) is forced further into the annular piston member, deforming both parts and dissipating energy.

Abstract: A fluid actuator (10) including a chamber (14) in which a piston assembly (17) reciprocates. The piston assembly (17) includes a pair of spaced pistons (18, 19) which divide the chamber (14) into three sections (20, 21, 22) and a passageway (29) which supports a valve member (30). Reciprocating movement of the slide valve member (30) causes fluid to be directed to the chamber sections (20) and (22) and thereby corresponding reciprocating movement of the piston assembly (17). The actuator (10) may be applied to the control of any device such as valves of internal combustion engines, fuel injectors or comprise actuating means for the piston of an internal combustion engine.

Abstract: The present invention relates to a high pressure piston sealing system. More particularly, the present invention relates to a sealing system adopted for rigorous marine applications which prevent or inhibit the use of a seal lubricant.

Abstract: A free-piston Stirling machine has a piston which can reciprocate and also rotate within a cylinder and which is supported and centered in the cylinder by a grooved dynamic bearing, the piston having two end faces which are acted upon during operation by different fluid pressures. The piston includes at least one sealing part having a circular-cylindrical smooth sealing surfaces and at least one bearing part which is provided in its peripheral surface with a groove pattern. The length of the sealing surface and the size of the gap between the sealing surface and the cylinder wall are selected such that the pressure difference across the bearing surface is reduced so that the piston remains free of radial dynamic instability during operation.

Abstract: The Compressor is small, compact and lightweight in that it is formed of the barest essentials. It has a pair of in-line cylinders, with pistons reciprocatable therein, and the crankshaft, having only one crank, is drivingly coupled to one of the pistons. The other piston is fastened to the crank-driven piston, in spaced-apart disposition, for a common reciprocation of the two. One of the cylinders serves as the crankcase.

Abstract: An improved piston-and-cylinder arrangement has a pressure-balanced piston head mounted on an actuator rod. The piston head is mounted for axial movement with the rod, and for radial movement relative thereto. Three annular ring-type seals are provided between facing cylindrical surfaces of the piston head and rod. The frictional impediment to radial movement of the piston head relative to the rod is minimized, and the improved device exhibits a reduction in the average maximum longitudinal frictional force per stroke.

Abstract: A piston for a swash plate type compressor is disclosed in which a plurality of similar pistons are reciprocated to provide a compressing operation by means of a swash plate which is mounted on the drive shaft and rotated in the compressor cylinder. The piston comprises a piston main body or blank made of aluminium or aluminium alloy, and a coating layer applied to the overall surface of the piston blank except central portions of both outer end faces of the blank, said coating layer being of ethylene fluoride or a copolymer of ethylene fluoride and a vinyl compound, the heat conductivity of which is lower than that of the piston blank.

Abstract: A conveyor system is designed for moving loads along a curved path and takes the form of a guide pipe having within it a piston-like driver which may be shuttled from one end to the other thereof by forcing driving fluid, as for example water and oil, into the one end or the other end of the pipe. A sleeve-like runner is placed on the outside of the pipe and is joined up with the driver by a magnet system which may take the form of a magnetic driving part on the driver and so placed thereon as to be radially spaced from the inner wall face of the pipe. The driver within the pipe and the runner on the pipe, together with any magnet system on them, have outer and inner forms taking into account the curved forms of the pipe.

Abstract: A double-acting pneumatic cylinder has a housing with a cylindrical chamber therein. A cylindrical piston is supported coaxially in the chamber for movement axially thereof and has a circumferential groove in the outer surface thereof. A pair of spaced, facing annular surfaces and a radially outwardly extending annular rib are provided in the groove, the rib being axially intermediate the annular surfaces. Two passageways in the housing communicate with the chamber on opposite sides of the piston for supplying compressed air to the chamber. A resilient O-ring encircles the piston within the groove and has annular bands of engagement with the chamber and the rib. The O-ring is transversely movable within the groove between two positions having annular bands of engagement with the respective annular surfaces in the groove in response to low air pressure selectively supplied to the chamber through the two passageways.

Abstract: An exhaust gas recirculating type diesel engine wherein part of the exhaust gas is recirculated from its exhaust system to its intake system. An annular groove is formed on the circumferential surface of the piston, and a ring for preventing small particles generated within the combustion chamber from being transferred is engaged within the annular groove.

Abstract: A free piston rabbit for an oil and gas well having gas seal and rotation features which improve its operation, reliability and durability. Circumferential grooves on the body of the rabbit have a turbulence-inducing configuration which improves their gas-sealing capacity while helically oriented slots develop rotation of the body of the rabbit to reduce the risk that the rabbit will become lodged in the production pipe and to improve its sealing capacity by hydrodynamic fluid action.

Abstract: A servo control mechanism for controlling the reciprocal movement of a piston member along the length of a curtain rod. The curtain rod is composed of a fluid pressure-tight tubular member made of a nonmagnetic material and having pressurized fluid supply ports therein adapted to supply pressure to opposite sides of the reciprocal piston member. A plurality of ring members, certain ones of which are made of magnetizable material, surround the curtain rod and are capable of movement along the length of the rod. A plurality of permanent magnets are reciprocally mounted inside the curtain rod and are magnetically coupled to certain ones of the curtain rings which are made of a magnetizable material. An elongated strand extends between the piston member and at least one of the permanent magnet members inside of the curtain rod so that a driven movement of the piston member will cause a forced movement of the permanent magnet therewith.