Abstract: While ceramic materials possess properties that make them suitable for use in fuel system components, they tend to be susceptible to failure when exposed to tensile stresses. The retention system described herein helps to reduce the tensile stresses experienced by a retained member by providing a retained member with an engagement structure, a multi-piece retention ring that engages the engagement structure, a resilient member coupled to the retention ring, and a retainer coupled around at least a portion of the retention ring and resilient member and spaced apart from the retention ring and/or resilient member by a gap. The retained member, retention ring, resilient member, and retainer are configured so that the retention ring is moveable in an axial direction relative to the retained member and so that the movement of the retention ring acts to expand the resilient member against the bias provided by the resilient member.

Abstract: The device comprises a cylinder (3) and a piston (7) which is guided free of contact relative to the cylinder (3). A gap seal (12) is provided between the lateral surfaces (15, 14) of the cylinder (3) and of the piston (7). The gap seal (12) has a very thin and uniform annular cross section. The lateral surfaces (14, 15) of the cylinder liner (4) and of the piston (7) are essentially smooth and comprise a material with a linear thermal coefficient of expansion which is lower relative to steel. The precise maintenance of the sealing gap and the central guidance of the piston (7) in the cylinder liner (4) is ensured through two guides (8, 9) connected rigidly with the housing (5). These guides (8, 9) are elastic in the direction of the central axis (2) of the piston-cylinder unit and highly rigid transversely to the central axis (2).

Abstract: The high temperature and high pressure seal retainer ring (40) is a continuous ring (40) of polyetheretherketone having an inner diameter that is substantially equal to outer diameters of a rear portion of a movable piston (14). The ring (40) is generally wedge shaped and is received within a wedge shaped opening defined by a surface of a bore (12) receiving the movable piston (14) and a sloped axially extending surface (22) at the rear portion of the piston (14). The piston (14) includes a groove (18) adjacent the sloped axially extending surface (22) and receives therein a rubber seal (30).

Abstract: A valve plug assembly for use in a steam throttle valve includes a valve body and a removable guide ring attached to one end of the valve body. An outer edge portion is removed from the guide ring at the interface with the valve body so that a circumferential groove is defined about the valve plug when the guide ring is assembled to the valve body. A slot is formed in one wall of the groove, preferably in the guide ring, and a wear ring inserted in the slot. The wear ring extends above the wall surface and terminates in an angled bearing surface. A pressure seal ring is formed with a mating bearing surface and is placed in the groove prior to assembly of the valve plug. The angular taper on the mating bearing surfaces causes some retraction of the pressure seal ring in response to sudden valve plug movement in the closed direction.

Abstract: A reciprocating pump for a cryogenic fluid includes a pump cylinder made of a material with low thermal expansivity, a piston displaceable in the pump cylinder, and self-lubricating piston rings made of polytetrafluorethylene held on the circumferential surface of the piston. The rings have a larger thermal expansivity than the pump cylinder. The arrangement allows optimum matching of piston rings and pump cylinder at cryogenic fluid pumping temperatures. The piston has a core made of a material with relatively large thermal expansivity which is surrounded by a spacer sleeve made of a material with a low coefficient of thermal expansion. The core protrudes on both sides from the spacer sleeve and has expanding regions increasing conically towards its free ends. The piston rings surround the core in the expanding regions and are supported against the end faces of spacer sleeve. The conical expanding regions bias the rings toward the cylinder at low temperatures to insure effective sealing.

Abstract: A collapsible plunger (10) for use in a pump is disclosed having a load carrying cylinder (12) forming in inwardly facing tapered end (14), a plug (16) forming an outwardly facing taper (18) mating the inwardly facing tapered end of the cylinder, a stud bolt (20) engaging plug 16 on one end, a plunger clamp end (22) abutting the cylinder on the opposite end and a nut (24) engaging the other end of the stud bolt. The nut is free to move away from the plunger clamp end so that the stud bolt is never in compression. The tapered end of the cylinder will yield to the plug at a predetermined force. The abutment surfaces (30 and 32) of the cylinder and plunger clamp end permit some relative movement between the two.