Butterfly valve

A butterfly valve, comprising

• a body including an annular hub having opposite ends disposable between spaced apart ends of a flowline and a neck extending from the side of the hub and having a bore therethrough,
• said bore having an outer enlarged cylindrical surface and an end surface at one end of the cylindrical surface,
• a seat of resilient material on the inner side of the hub,
• a disc having an outer periphery for tightly engaging the seat,
• a stem having
• an inner end fitting closely through the seat and into a hole in the hub,
• an inner end fitting closely through the seat and into a hole in the hub,
• an outer end fitting closely through the seat and the bore through the neck, and
• a portion intermediate its end extending through the disc and including a non-circular part fitting closely within a non-circular part of the disc, whereby the disc may be rotated with the stem between open and closed positions by means of an actuator connected to said outer end of the stem,
• said stem being moveable axially into and out of close-fitting position within the hub seat and disc, and
• a seal ring about the stem within the cylindrical surface of the bore and supported on the end surface thereof for sealably engaging there between,
• a bushing about the stem and supported on the seal ring within the cylindrical surface of the bore, and
• means retaining the stem, seal ring and bushing in said positions including
• a groove about the cylindrical surface,
• a groove about the stem,
• ring segments having inner edges releasably disposed within the groove about the stem and over the bushing and outer edges fitting closely within the cylindrical surface to hold inner edges in the stem groove, and
• a ring in the groove about the cylindrical surface and engaging the outer sides of the ring segments,
• said ring being split at one location about its circumference to permit it to be sprung into and out of the groove in the bore when removed from within the cylindrical surface.