Cryogenic pump multi-part piston with thermal expansivity compensated polytetrafluoroethylene seal rings
First Claim
1. A reciprocating pump for a cryogenic fluid comprising:
- a pump cylinder made of a material with low thermal expansivity,a piston displaceable in said pump cylinder, andpiston rings made of a self-lubricating material with a large expansivity than the material of said pump cylinder held on the circumferential surface of said piston,said piston comprising a core made of a material with relatively large thermal expansivity and a spacer sleeve made of a material with low thermal expansivity surrounding said core,said core protruding on both sides from said spacer sleeve and having expanding regions increasing conically towards its free ends,andsaid piston rings surrounding said core in said expanding regions and supported against the end faces of said spacer sleeve.
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Accused Products
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.
28 Citations
7 Claims
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1. A reciprocating pump for a cryogenic fluid comprising:
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a pump cylinder made of a material with low thermal expansivity, a piston displaceable in said pump cylinder, and piston rings made of a self-lubricating material with a large expansivity than the material of said pump cylinder held on the circumferential surface of said piston, said piston comprising a core made of a material with relatively large thermal expansivity and a spacer sleeve made of a material with low thermal expansivity surrounding said core, said core protruding on both sides from said spacer sleeve and having expanding regions increasing conically towards its free ends, and said piston rings surrounding said core in said expanding regions and supported against the end faces of said spacer sleeve. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification