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:
Dec. 27, 1994
Filed:
Dec. 06, 1993
Peter M Kent, Greengates Warthill, GB;
ABB Vetco Gray Inc., Houston, TX (US);
Abstract
A metal stem seal for sealing between a movable stem and a stem opening in a valve body has an annular seal body through which the stem extends. The seal has a flexible annular seal leg depending from the seal body for sealing against the stem. The inner surface of the seal leg has at least one groove defining a plurality of sealing lands, including at least a lower sealing land and upper sealing land. The undeflected inner diameter of the lower sealing land is selected so that upon insertion of the stem through the seal, the seal leg deflects outward. The undeflected diameter of the upper sealing land is selected so that it is larger than the undeflected inner diameter of the lower sealing land. The undeflected diameters of additional sealing lands are selected so that they are successively larger than the undeflected inner diameters of the sealing lands below them. Increased fluid pressure in the stem opening causes the seal leg to flex inward causing additional sealing lands to contact the stem.