US 5,042,365 AGranted

Annular preloaded seal for a sliding piston in cylindrical tank

AssigneeRockwell International Corporation

InventorIrwin E. Rosman

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Abstract

A peripheral sliding seal for sealing the liquid propellant in a cylindrical tank 10 containing a piston 14 for positive expulsion of the liquid propellant. The seal comprises a peripheral inward flange member 16 around the piston periphery adjacent the inner wall of the tank, an annular pressure ring 18 bonded to the flange member 16 and forming several recesses therewith, one recess containing a compliant sealing ring 20 and the other containing a shear seal 32 bonded both to the flange member 16 and to the entrance head 12 of the tank. The bonds prevent internal and external leakage of the liquid fuel during storage. Pressurization of the piston 14 permits the piston 14 to move and breaks the shear seal 32. The compliant-ring seal slides with the piston 14, the compliant ring 20 being pressed against the inner wall of the tank by resilient fingers 34 of the pressure ring 18 to form a sliding seal.

Claims25

Dependent claims

An annular sliding seal for sealing the space between an inner wall of a tank for holding a liquid and an adjacent circular periphery of an internal piston for expelling the liquid therefrom, said tank having a cylindrical body, an entrance head for closing an entrance end of the cylindrical body and an exit end from which the liquid is expelled, said seal comprising:

a head flange formed on the entrance head and extending toward the exit end of the tank to enclose an outer wall of the tank at its entrance end, the flange being bonded to said outer wall;
a shoulder member formed on the periphery of said piston and extending inwardly thereof, said shoulder member having a longitudinally extending shoulder flange;
a compression ramp formed on and extending inwardly from an inner surface of the entrance head and spaced from a juncture between the entrance head and the cylindrical body;
a pressure ring located outwardly of said shoulder flange and bonded thereto, said pressure ring having a slope at one end which conforms to and rests upon the compression ramp when the entrance head is fitted to the cylindrical body, said pressure ring forming a first recess with the entrance head and a second recess with the shoulder flange, the entrance end of the tank and the entrance head, the pressure ring being fabricated from resilient material and having an inward pressure exerted on it by the compression ramp, the resilience of the pressure ring exerting an outward pressure against the ramp;
a sealing ring made of compliant material and located within the first recess;
and
an annular shear seal located in the second recess, wherein, when said piston is pressurized and caused to slide, the shear seal ruptures, and the pressure ring slides off the compression ramp and exerts outward pressure against the compliant ring so that it forms an annular sealing contact with the inner wall of the tank throughout the movement of the piston.

4 more elements

In a cylindrical tank having an entrance head fitting on an entrance end of the tank and a slidable internal piston having a circular periphery circumferentially abutting an inner wall of the tank, a sliding annular seal comprising:

first means for effecting a static seal between the piston periphery, the entrance end of the tank, and an exit end of the entrance head;
and
second means for effecting a dynamic seal between the piston periphery and the inner wall of the tank and interacting with said first means when the piston is set in motion, said second means including:
a compliant sealing ring, and
a pressure ring in contact with said compliant sealing ring, said pressure ring including a finger section having resilient fingers extending longitudinally in the entrance head direction from a band section which has band of unslotted material, the finger section sloping outwards from the band section in the normal, unstressed condition of the pressure ring;
a sloping compression ramp extending inwards from the inner surface of the entrance head;
a slope at the entrance end of the pressure ring, which slope conforms to and rests upon the compression ramp, so that the compression ramp exerts an inward force on the resilient fingers of the pressure ring whereby the outward normal slope of the fingers is reduced as long as the pressure ring rests on the compression ramp;
wherein, when the piston moves along the inner wall of the tank, said pressure ring applies outward pressure on said sealing ring thereby keeping the sealing ring in sealing contact with the inner wall of the tank.

5 more elements

Dependencies are inferred from the claim text.