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. 27, 1990
Filed:
Apr. 10, 1989
Michael E Jones, Los Ososo, CA (US);
Joseph H Nichols, San Luis Obispo, CA (US);
Ronald G Hendry, Los Osos, CA (US);
Charles M Obermeyer, Littleton, CO (US);
Cryolab, Inc., San Luis Obispo, CA (US);
Abstract
A sealed valve intended for use in ultrahigh purity applications uses a metal-to-metal seal in a crucial, but unacessible, portion of the valve. The metal-to-metal seal avoids the use of a weld which because of the location could not be adequately cleaned, and avoids the use of an O-ring seal. The O-ring seal typically would have a leak rate on the order of 10.sup.-7 standard cubic centimeters per second of helium, but the metal-to-metal seal provides a leakage rate of less than 10.sup.-13 sccm/s. In the preferred embodiment, the seal is formed by forcing a conical part into the opening of a bore. The force used is small emough to avoid permanent deformation of the sealing parts, and thus the seal can be opened and closed any number of times without degradation.