A device for transferring fluid between two separate structures includes a rigid pipe with a double shell extending along a longitudinal axis. The pipe includes an outer-shell housing (in the inner vacuum space thereof), at least one inner duct for fluid transfer, and at first and second ends thereof, includes respective first and second rigid connections of the outer shell to the first structure and second structures, respectively. The first and second ends of the outer shell are rigidly connected to the at least one inner duct. The pipe comprises a system to compensate for movements in the longitudinal direction.

A flexible metal seal assembly for isolating one or more fluids in an operative region of a machine comprises a first flexible metal seal and a second flexible metal seal arranged in series, allowing the additional exertion of a spring bias. The inner surface of the first flexible metal seal is restrainably and hermetically attached to the outer surface of a metallic coupler, while the outer surface of the second flexible metal seal is restrainably and hermetically attached to the inner surface of the metallic coupler. Amongst other applications, the assembly may be used in a valve seal, or in an engine fuel pump, where it serves to isolate lubricating oil from fuel, or one fluid from a region, where one fluid may be present on an actuator that reciprocates within the second flexible metal seal or outside of the first flexible metal seal.

A flexible metal seal assembly for isolating one or more fluids in an operative region of a machine comprises a first flexible metal seal and a second flexible metal seal arranged in series, allowing the additional exertion of a spring bias. The inner surface of the first flexible metal seal is restrainably and hermetically attached to the outer surface of a metallic coupler, while the outer surface of the second flexible metal seal is restrainably and hermetically attached to the inner surface of the metallic coupler. Amongst other applications, the assembly may be used in a valve seal, or in an engine fuel pump, where it serves to isolate lubricating oil from fuel, or one fluid from a region, where one fluid may be present on an actuator that reciprocates within the second flexible metal seal or outside of the first flexible metal seal.

A compensator, having a first corrugated bellows section, a second corrugated bellows section, an intermediate pipe section positioned between the first corrugated bellows section and the second corrugated bellows section, a first attachment flange, and a second attachment flange. The first corrugated bellows section engages the first attachment flange and intermediate pipe section. The second corrugated bellows section engages the second attachment flange and intermediate pipe section. An intermediate flange is positioned between the first attachment flange and the second attachment flange and surrounds the intermediate pipe section at the outside without a a rigid connection to the intermediate pipe section. The intermediate flange is connected by first tension rods to the first attachment flange and by second tension rods to the second attachment flange.

A bellows restraint includes a first bracket having a first mount and a first arm extending from the first mount, a second bracket having a second mount and a second arm extending from the second mount to be adjacent to the first arm with the second arm having at least one through-hole, and a first fastener extending through the at least one through-hole of the second arm to connect to the first arm with the first fastener having a cross-sectional area that is smaller than a cross-sectional area of the at least one through-hole to allow the first bracket to move in relation to the second bracket.