Stem seal and retainer for gate valve

Claim 1

In combination with a non-rising stem gate valve of the type comprising a body portion with flow openings, a bonnet portion attached to said body portion in fluid-tight relationship thereto, means for opening and closing said flow openings, said means including a stem extending through a tubular opening in said bonnet, the improvement comprising a stem seal shoulder on an inner surface of said bonnet surrounding said tubular opening, a collar surrounding an intermediate portion of said stem and being of greater diameter than said tubular opening to prevent said stem from movement outwardly with respect to said bonnet, an upper shoulder on said bonnet surrounding said tubular opening exteriorly of said bonnet, means, entirely within said tubular opening, connecting said stem and said upper shoulder to prevent said stem from moving inwardly with respect to said bonnet and a slip fitting seal cartridge surrounding said stem and resting on said upper shoulder, said cartridge having an annular notch, a first ''''O'''' ring seal inserted in said notch, and being radially compressed between said seal cartridge and said bonnet portion, said stem having an annular groove therein, and a second ''''O'''' ring seal inserted in said groove and being radially compressed between said stem and said seal cartridge to prevent fluid leakage along said stem.