Abstract: Disclosed is an expanding gate valve that expands the gate assembly by engagement of symmetrical opposing inclined cam surfaces with corresponding symmetrical opposing wedges, where at least one of the wedges is driven by the stem that moves the gate assembly, and where the gate assembly is urged back toward the retracted position by at least one lateral-force-inducing member at least when the gate assembly is not in the closed position. Example compact and full body gate valve designs are disclosed. Lateral-force-inducing members may comprise one or more springs, such as a snap-ring, or may comprise cam followers running against surfaces defining the gate members' movement profile. A sealed sleeve is also disclosed that seals the interior of the valve body from pressure in the pipeline when the valve is open, while allowing the gate assembly to expand and retract laterally.

Abstract: A dual stage hydraulic actuator (9) for actuation of an expanding gate valve (10). The actuator is mountable to the valve housing and comprises a housing 40 which defines a piston chamber 41 and a primary piston (61) slidably received therein. An actuator stem (23) connects the piston (61) to the valve gate assembly (20). A secondary piston (77), of smaller piston area than the primary piston (61), is slidably received in a piston receiving bore (75) which is formed in the fluid receiving face of the primary piston. A piston rod (80) connects coaxially with the piston (77) and extends through the end (52) of the actuator housing. The actuator is responsive to hydraulic fluid pressure which when applied through an inlet (71) of the actuator housing to one side of the pistons (61, 77) drives the actuator stem and gate assembly to an operational open or closed position of the valve.

Abstract: An expanding gate valve according to the present invention includes a gate system incorporating a pair of segments, one segment being formed to define opening cam surface means and the other segment being formed to define closed cam surface means. Spreader means is positioned in stationary manner within the valve chamber of the valve and includes opening and closing cam surface means that is engageable respectively with the cam surface means of the segments to achieve wedging, mechanically energized sealing enhancement between the segments and the valve seats as the gate segments reach the open or closed positions thereof during operation. The body structure of the valve is formed to define a valve chamber of generally cylindrical configuration within which may be located a pair of partially cylindrical seat carrier elements that properly position a pair of seat rings in relation to the valve body and the planar sealing surfaces of the gate segments.

Abstract: A housing, connectable to a pipe, has therein an opening, a chamber, a stationary sealing seat, and a movable sealing seat displaceable toward and away from the stationary sealing seat. A slide plate is movable from an open position, exterior of the housing, through the opening to a closed position between the sealing seats to block the pipe. A closing element closes the opening and seals the chamber when the slide plate is in the open position.