Patent ID: 7481418

Claim:
A two-part back cap for a plug valve, comprising: a back cap seal body having an inner end and an outer end, the inner end comprising a seal rim that includes at least one O-ring groove that accepts an O-ring for providing a fluid seal between the back cap seal body and a plug valve body of the plug valve; and a back cap retainer nut having pin threads that threadedly engage box threads in the plug valve body for securely retaining the back cap seal body within the plug valve body, the back cap retainer nut having an inner end that supports only a first part of the outer end of the back cap seal body until the plug valve is subjected to high fluid pressures, the outer end of the back cap seal body comprising first and second surfaces, the first and second surfaces being inclined towards the seal rim at different angles of inclination with respect to a line perpendicular to an axis of the back cap seal body and the back cap retainer nut supports only the first surface until the plug valve is subjected to the high fluid pressures.