Abstract: A valve has an annular seat member coaxially mounted in a groove in the valve body around the outlet passageway. The groove has parallel sides which are perpendicular to its bottom. The seat member has a lesser radial thickness than the groove and is mounted in the groove in an uncompressed condition with substantial clearance between the sides of the seat member and the adjacent sides of the groove. A lip about the outer face of the seat member adjacent its inner periphery normally contacts the adjacent valve member in sealing relation. The portion of the seat member which fits within the groove has an inclined inner annular portion that does not contact the groove bottom and an outer resting surface which contacts the groove bottom. The seat member is formed of a deformable material with the lip being deformed when the seat member is loaded in compression as the valve is assembled.

Abstract: A ball valve seat assembly has a seat ring with an annular recess around an inner annular portion thereof and a resilient seat ring insert mounted in the recess. The seat ring has a radially outwardly extending groove located within the recess. The insert has a radially outwardly extending retaining flange which is engaged in the seat ring groove to anchor the insert. The insert is sufficiently deformable to be radially inwardly deformed temporarily as the flange is moved through the interior of the seat ring and into the groove. The insert has a face portion that is sealingly engaged with the ball valve member. The seat ring and the insert are biased toward the ball valve member and a peripheral seal is provided around the seat ring to seal with the valve body. The seat pocket inner side extends in an overlying relation to a portion of the insert in order to prevent radially inward movement of the insert.