Controlled floating seat for gate valves

摘要

A controlled or limited floating seat for an expanding type gate valve. The seat is received in a shrink fit in a groove formed around the flow passage of the valve adjacent the valve chamber. The seat is able to move in the groove toward the valve chamber until a frusto-conical outer side of the seat contacts a frusto-conical outer surface of the groove to prevent the seat from dragging against the gate assembly in the collapsed condition thereof. In the expanded condition of the gate assembly, the seat is bottomed in the groove with a sealing surface of the seat tightly sealing against the gate assembly.