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:
Aug. 11, 1987
Filed:
Jan. 30, 1986
David P Herd, Houston, TX (US);
Smith International, Inc., Newport Beach, CA (US);
Abstract
A split gate for a gate valve regulating fluid flow with reduced gate drag. The split gate comprises a plurality of members for sealing a flowway intersecting a valve chamber. A first member seats against a first portion of the flowway and has a pressure-balancing surface pressure-isolated from the first flowway portion and from the valve chamber. A second member seats against a second portion of the flowway and allows pressure in the second flowway portion to bear on the pressure-balancing surface of the first member. Pressure in the valve chamber exceeding pressures in the flowway portions creates pressure differentials pressing the gate members more firmly against their seats, thereby increasing the frictional resistance opposing reciprocation of a closed gate to its open position. The invention provides that, to the extent of the area of the pressure-balancing surface, the net pressure differential seating the first member is the first flowway portion-to-second flowway portion pressure differential, in place of the higher pressure differential between the valve chamber and the first flowway portion. A similar result is obtained for the second member by reducing the areas for pressure differential to act on the second member. The invention thus reduces the effects of internal valve pressure differentials to lower the frictional gate drag resisting opening of the gate.