Patent ID: 7635113

Claim:
A ball valve comprising: a valve body; a cylindrical seal surface in said valve body; a ball disposed in the valve body; a spring disposed in the valve body; a gland surrounded by said cylindrical seal surface, said gland having an outer end surface, a radially outermost surface that extends axially inward from the outer end surface, an axially innermost end surface, a gland seal surface having a diameter that is smaller than a diameter of said radially outermost surface and that extends axially outward from the innermost end surface, and an annular shoulder surface that extends between said radially outermost surface and said gland seal surface, wherein the gland is disposed in the valve body such that the spring applies force to the outer end surface; a seat having an end surface and a seat seal surface disposed in the valve body such that the force applied by the spring presses the gland against the seat end surface and urges the seat seal surface against the ball; wherein the gland seal surface of the gland, the annular shoulder surface of the gland, and the end surface of the valve seat together define an annular seal groove; and a seal member that is separate from said seat disposed in the annular seal groove, wherein the seal member contacts the gland seal surface and the cylindrical seal surface to form a seal against the gland seal surface and the cylindrical seal surface to prevent fluid flow between gland seal surface and the cylindrical seal surface.