US 4,796,858 AGranted

Dual seal valve

AssigneeHalliburton Company

InventorTerry D. Kabel

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Abstract

A dual seal valve having a bubble-tight primary seal and a metal-to-metal secondary seal for sealing engagement with a rotating valve element. The primary seal is preferably a composite seal comprising a relatively hard, high lubricity element bonded to a relatively soft, resilient elastomeric element. The elastomeric element biases the hard element into sealing engagement with the valve element. Several embodiments of the primary seal are disclosed. Tapered inserts are positioned on opposite sides of the valve element, and a seal groove is provided on a tapered outer surface of the insert and adapted for receiving a seal therein. The groove has an enlarged portion which provides a seal relief, allowing deformation and unsealing disengagement of the seal when pressure thereon exceeds a predetermined level. While plug valve embodiments are disclosed, the dual seal arrangement and seal relief are also applicable to ball valves, spherical plug valves, and other valve types having rotating valve elements.

Claims18

Dependent claims

A valve comprising:

body means having inlet means and outlet means thereon and defining a central cavity therein in communication with said inlet and outlet means;
insert means disposed in said central cavity and defining an opening therethrough in communication with at least one of said inlet and outlet means;
valve means disposed in said central cavity and rotatable with respect to said body means and said insert means, said valve means defining an opening therethrough in communication with said opening in said insert means when said valve means is in an open position and spaced from said opening in said insert means when in a closed position, one of said valve means and said insert means having a sealing surface thereon and the other of said valve means and said insert means defining a seal groove therein adjacent said sealing surface;
and
composite seal means disposed in said seal groove and comprising:
a relatively hard, high lubricity element adapted for sealing engagement with said sealing surface;
and
a relatively soft, elastomeric element integrally connected to said hard element and adapted for resiliently biasing said hard element toward said sealing surface,
wherein a radial side wall of said composite seal means defines an annular concave groove therealong such that at least a portion of said side wall of said elastomeric element is spaced from a corresponding side wall of said seal groove.

6 more elements

A plug valve comprising:

a body having an inlet and an outlet and defining a central cavity therein in communication with said inlet and outlet, at least a portion of said central cavity being bounded by a tapered wall;
an inlet side insert disposed adjacent said inlet and defining an inlet side insert opening in communication with said inlet, said inlet side insert having a tapered outer surface adapted for engagement with said tapered wall of said body and a substantially cylindrical inlet side inner surface, said inlet side inner surface having a sealing portion thereon adjacent said inlet side insert opening and defining an inlet side groove therein surrounding said sealing portion;
an outlet side insert disposed adjacent said outlet and defining an outlet side insert opening in communication with said outlet, said outlet side insert having a tapered outer surface adapted for engagement with said tapered wall of said body and a substantially cylindrical outlet side inner surface, said outlet side inner surface having a sealing portion thereon adjacent said outlet side insert opening and defining an outlet side groove therein surrounding said sealing portion on said outlet side inner surface;
a substantially cylindrical plug disposed in said central cavity between said inserts and having a plug opening therethrough in communication with said insert opening when said valve is in an open position, said plug having a plug sealing surface thereon;
and
resilient seal means disposed in each of said grooves for providing sealing engagement between said plug sealing surface and said inserts outwardly of said sealing portions on said inner surfaces of said inserts, said sealing portions providing metal-to-metal sealing with said plug sealing surface, wherein at least one of said tapered walls in said body and the tapered outer surface of at least one of said inserts defines a seal groove therein surrounding the opening in the corresponding insert, said seal groove having an enlarged segment extending radially outwardly away from said opening in said corresponding insert and in a direction toward said cylindrical plug;
and
further comprising a resilient seal disposed in said seal groove for providing sealing engagement between said body and said one of said inserts when a pressure exerted on said seal is below a predetermined level, said seal being at least partially deformable into said enlarged segment when said pressure exceeds said predetermined level.

5 more elements

Dependencies are inferred from the claim text.