Shaft seal for corrosion resistant butterfly valve
First Claim
1. In a rotatably operable pipe line valve for corrosive service including a metal body defining a flow passage between an inlet and an outlet, a closure member in said passage operable between open and closed positions thereof, a thruport seal in said passage for cooperating with said closure member in its closed position and an operator shaft extending through said body from a driving connection internally enclosed within said closure member to a location external of said body, an annular seal member surrounding said shaft in axially squeezed relation interposed between said closure member and said body thereat, said seal member being operably effective for shaft protection against line content independent of said thruport seal and comprising an elastomer and deflection control means operative against said elastomer to restrict radial deflection thereof.
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Accused Products
Abstract
A valve, such as a butterfly valve, having an offset closure vane supported on stub shafts for operating the vane in the flow passage of the body, has all exposed and/or potentially vulnerable metal surfaces encapsulated in a corrosion resistant polymeric plastic coating. Annular seals of resilient composition bonded to a steel insert are formed with an annular radial recess at an axially intermediate location and are positioned on the vane shafts axially squeezed between vane and body bosses thereat. In this arrangement, controlled deflection is provided by the seals in effecting a positive sealing pressure whereby the shafts are protected against exposure to line content. At the same time, the seals are rendered self-packing in response to pressure of line content while also functioning to assure concentric centering of the vane in the body passage.
22 Citations
10 Claims
- 1. In a rotatably operable pipe line valve for corrosive service including a metal body defining a flow passage between an inlet and an outlet, a closure member in said passage operable between open and closed positions thereof, a thruport seal in said passage for cooperating with said closure member in its closed position and an operator shaft extending through said body from a driving connection internally enclosed within said closure member to a location external of said body, an annular seal member surrounding said shaft in axially squeezed relation interposed between said closure member and said body thereat, said seal member being operably effective for shaft protection against line content independent of said thruport seal and comprising an elastomer and deflection control means operative against said elastomer to restrict radial deflection thereof.
Specification