A cylindrical valve chamber having a vertical axis is formed in the valve body and intersects the flow passage to define diametrically opposed inlet and outlet openings in the chamber.GATE VALVES The flow passage at the position of the openings in the chamber is provided with a portion of slightly enlarged diameter.

A pair of identical valve seats, each valve seat having a cylindrical portion and a nose portion, the nose portion terminating in a planar portion and the valve seat having a bore extending therethrough, is provided with the cylindrical portion of each valve seat being secured within the enlarged diameter portion of the flow passage at one end of the openings. The nose portion of each valve seat is located within the valve chamber and the bores of the valve seats are coaxial and constitute extensions of the flow passages.

A carrier frame is shiftable vertically in the valve chamber between a valve open and a valve closed position. A pair of mirror image gates are located within the carrier frame in face to face relationship with coaxial openings in the lower portion thereof, the surfaces of the gates facing the valve seats being planar. The coaxial openings in the gates are coaxial with the bores in the valve seats when the carrier frame is in the open position and no longer communicate with the bores in the valve seats when the carrier frame is in its closed position. The gates are so mounted in the carrier frame as to be shiftable vertically in the carrier frame and as to be shiftable toward and away from each

other in the carrier frame.

Finally, means are provided on the carrier frame and on the gates to shift the gates toward the valve seats and away from each other when the carrier frame is in the open and closed positions and to permit the gates to shift toward each other when the carrier frame is being shifted between its open and closed positions.Gate Valves In practice, the means on the carrier frame and on the gates to shift the gates comprises a pair of cylindrical bosses on the inside elongated surface of each elongated side of the carrier frame and a recessed camming surface on each side of each of the gates adapted to cooperate with their respective one of the bosses.

Finally, according to the present invention pressure relief wedges may be located on either side of the carrier frame, with each wedge being associated with a respective groove in a valve seat, so as to align the gates and the carrier frame as the carrier frame is shifted vertically in the valve chamber. The pressure relief wedges are slightly tapered so as to force the gates away from the surface of the valve seats, breaking the pressure tight seal between the seat and the gate.Cast Gate, Globe, Check Valves

The improved gate valve of the present invention will reduce the operating torque on the valve stem by eliminating the sliding friction of the gate against the seat face caused by the pressure. The means on the carrier frame and on the gates to shift the gates forces the gates to move away from the valve seats. Finally, the pressure release wedges reduce the concentration of erosion on the seat and gate sealing surfaces.

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