The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 21, 1989
Filed:
Jun. 17, 1987
Gottfried Schneider, Stuttgart, DE;
Walter Peschka, Sindelfingen, DE;
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.