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:
Oct. 02, 1984
Filed:
Sep. 02, 1983
Danny S Meyer, Richmond, TX (US);
ACF Industries, Incorporated, New York, NY (US);
Abstract
A valve having a back-sealing capability provided by a pressure energizable sealing assembly which becomes operative independently of valve stem movement and valve element position for sealing between the valve casing (10, 22) and the valve stem (21) in the event of loss of sealing by the valve stem packing (33). A sealing ring (45) of the sealing assembly is installed with limited axial movement in an enlargement (20a) of the valve stem bore located intermediate the valve stem packing (33) and the valve chamber (11). The sealing ring (45) is provided with inner peripheral sealing surfaces (54) and an outer peripheral sealing surface (51) conforming in configuration to that of a corresponding sealing surface (42) provided in the stem bore enlargement. Yieldable spacer means (47) are provided for normally maintaining the sealing ring with the outer peripheral sealing surface (45) of the sealing ring in close proximity to the sealing surface (42) of the valve stem bore enlargement whereby the sealing assembly is responsive to a pressure differential induced across the sealing ring by a stem packing leak to establish a pressure energized metal-to-metal seal between the valve casing and the valve stem. In a modified form, the yieldable spacer means includes a eutectic member (62) which melts at a predetermined temperature whereby the magnitude of the packing leak at which the sealing assembly becomes operative is minimized.