Gate valve

Abstract

A high-pressure, high-temperature gate valve which uses a flat faced gate seating on a flat and preferably interchangeable seat, the gate having a wedge-shape on the upstream side which assists in forcing the seating surfaces together which is highly desirable in high-pressure conditions. The inlet and outlet ports are completely covered in the closed position which enables the valve to withstand extreme pressures. The gate valve further includes a valve stem extending through said chamber and said body having a threaded lower end cooperating with a threaded recess in said gate, said stem being axially rotatable in a bearing means in said body to raise and lower said gate between said open and closed positions, said bearing means including a stuffing box, a lower seat and an upper seat through which said stem extends, said stem including an integral collar located between said seats. The upper seat is provided by the stuffing box. The valve body is formed by two members, one the main body part which has integral therewith the neck portion containing the bearing means and a cover plate removably adapted to a side of the main body portion, the cover plate and the main body portion having mating flat surfaces with a trapped seal therebetween in a recess, such that on removal of the cover plate the whole of the interior of the chamber is exposed to permit machining of the interior of the chamber.