Compact expanding gate valve

摘要

A compact expanding gate valve having a valve body defining a flowway and having spaced internal seat rings. Guide elements project internally from the valve body. A valve stem driven gate and segment assembly is movable within the valve body between open and closed positions relative to the seat rings and has control arms mounted by actuating pins to each side of gate and segment members of the gate and segment assembly. The control arms are movable linearly with the gate and segment assembly and are disposed in guided relation with the guide elements during opening and closing movement. During initial movement of the gate and segment assembly from the closed position, the pinned connection of the control arms to the gate member and the segment member causes the control arms to pivot responsive to relative linear movement of the gate and segment members and apply collapsing force to the gate and segment members to collapse the gate and segment assembly to minimize frictional contact thereof with the seat rings and permit its movement by the valve stem from the closed position to the open position.