Patent ID: 7255329

Claim:
A gate valve comprising: (a) a valve body having: a.1 a flow passage extending between a first port and a second port; a.2 a gate housing section having an inner end and an outer end, and gate housing wall defining a cylindrical gate chamber transversely intersecting and in fluid communication with the flow passage; (b) a generally cylindrical gate member having an inner end and an outer end disposed within the gate chamber and movable between: b.1 an open position, in which a fluid can flow through the flow passage between the first and second ports; and b.2 a closed position, in which the gate member blocks fluid flow between the first and second ports; (c) an elongate valve stem operable to move the gate between the open and closed positions, with the longitudinal axis of the valve stem being offset from but parallel to the longitudinal axis of the cylindrical gate member, and with a first end of the valve stem engaging the gate member such that the valve stem is freely rotatable, but longitudinally retained, relative to the gate member; and (d) valve stem mounting means whereby rotation of the valve stem will move the valve stem longitudinally relative to the valve body.