BALL VALVE SEAT ASSEMBLY HAVING A REMOVABLY MOUNTED FACE SEAL INSERT

摘要

BALL VALVE SEAT ASSEMBLY HAVING A REMOVABLY MOUNTED FACE SEAL INSERT 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 en-gaged in the seat ring groove to anchor the insert. The insert is sufficiently deform-able 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, In one construction an O-ring is compressed in the seat pocket against the seat ring and the insert to urge them toward the valve member and to seal around the seat ring. In another construction an O-ring seal is provided around the perimeter of the seat ring and springs are used to bias the seat member toward the ball valve member.