Gate valve assembly with an axially flexible seat

摘要

A gate valve assembly having metallic valve seats that are axially resilient and maintain a static sealing interface between the valve seat and a body pocket and a sliding dynamic sealing interface between the valve seat and a gate in the valve assembly. The valve seats are annular members having slots formed radially through the valve seats from the inner and outer circumferences. Sleeves may be provided that are coaxial to the valve seats; the sleeves may be on the inner surface of the valve seats, outer surface of the valve seats, or both. Shims may optionally be set in the slots.

主权项

1. A gate valve assembly comprising:
a body having a valve seat pocket; a gate moveable in the body between an open and a closed position; a resilient annular metal valve seat mounted in the body, having a bore with a flow passage axis and changeable from an elongate configuration with a rearward end in static sealing contact with the valve seat pocket in the body and a forward end in dynamic sealing contact with the gate to a compressed configuration with the rearward end in static sealing contact with the valve seat pocket in the body and the forward end in dynamic sealing contact with the gate and having a mid-portion between the forward end and the body that defines a pressure barrier; wherein the rearward end, the mid-portion and the forward end of the valve seat are integrally formed from a single piece of metal; at least two circumferentially extending inner slots in the bore within the mid-portion of the valve seat; at least two circumferentially extending outer slots on an outer circumference of the mid-portion of the valve seat, the inner slots and the outer slots alternating with each other, defining a serpentine wall of the valve seat that has an axial thickness greater than an axial width of each of the inner and outer slots; an annular bore recess on a curved surface of the bore of the mid-portion of the valve seat, the bore recess defining an inner forward shoulder on the valve seat that faces toward the valve seat pocket in the body; an inner sleeve in the bore recess and coaxial with the valve seat, the inner sleeve having a forward end and a rearward end; an annular outer recess on a curved surface of the outer circumference of the mid-portion of the valve seat, the outer recess defining an outer forward shoulder on the valve seat that faces toward the valve seat pocket in the body; an outer sleeve in the outer recess, the outer sleeve having a forward end and a rearward end; wherein the inner sleeve and the outer sleeve each have a length less than a distance from the inner and outer forward shoulders to the valve seat pocket when the valve seat is in the elongate configuration; and wherein the forward ends of the inner sleeve and the outer sleeve contact the inner forward shoulder and the outer forward shoulder, respectively, and the rearward ends of the inner sleeve and the outer sleeve engage the valve seat pocket when the valve seat is in the compressed configuration.