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:
Apr. 21, 1987
Filed:
Dec. 27, 1983
Danny S Meyer, Richmond, TX (US);
William S Shelton, Houston, TX (US);
Joy Manufacturing Company, Pittsburgh, PA (US);
Abstract
An improved heat responsive backseat for gate valves which includes a rotating valve stem (50) carried by a bonnet assembly (14) for actuation of a gate member (40). A fusible stem ring (126) supports the valve stem at an outer portion thereof (68) within a roller bearing chamber (56) of the bonnet assembly. The valve stem (50) moves axially outward from the valve chamber (20) when the fusible stem ring (126) melts due to an external fire condition to bring a valve stem backseat portion (64) into sealing engagement with a bonnet seat portion (54). The valve stem (50) moves axially outward from the valve chamber (20) independently of roller bearings (74, 76) contained within roller bearing chamber (56) such that the roller bearings (74, 76) remain axially fixed with respect to the bonnet assembly before, during and after the shifting of the valve stem. Therefore, the valve stem may be easily rotated after the fire condition has been extinguished without the occurrence of cocking or wedging between the bearing means and valve stem. Accordingly, a secondary metal-to-metal seal is provided between the valve stem (50) and bonnet assembly (14) such that if the primary packing (104) is destroyed by the fire condition the gate valve will not leak flowline fluid exteriorly of the gate valve.