The opening and closing part of a gate valve is a gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, and cannot be adjusted or throttled. The gate has two sealing surfaces. The two sealing surfaces of the commonly used mode gate valve form a wedge. The wedge angle varies with valve parameters, usually 50, and 2°52' when the medium temperature is not high. The gate of the wedge gate valve can be made into a whole, called a rigid gate; it can also be made into a gate that can produce a small amount of deformation to change its manufacturability and compensate for the deviation of the sealing surface angle during the processing. The plate is called an elastic gate. Stainless steel gate valve materials are divided into 304 stainless steel gate valve, 316 stainless steel gate valve, 321 stainless steel gate valve.
The types of stainless steel gate valves can be divided into wedge gate valves and parallel gate valves according to the sealing surface configuration. Wedge gate valves can be divided into: single gate type, double gate type and elastic gate type; parallel gate type gate valves It can be divided into single gate type and double gate type. Divided according to the thread position of the valve stem, it can be divided into two types: open stem gate valve and dark stem gate valve. This type of valve should generally be installed horizontally in the pipeline.
When the valve is opened, when the lift height of the gate is equal to 1:1 times the valve diameter, the fluid passage is unblocked, but this position cannot be monitored during operation. In actual use, the apex of the valve stem is used as the mark, that is, the unmovable position, as its fully open position. In order to take into account the locking phenomenon caused by temperature changes, it is usually opened to the top position, and then rewind 1/2-1 turn, which is the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the gate (ie stroke).
In some gate valves, the stem nut is set on the gate, and the rotation of the handwheel drives the rotation of the valve stem to lift the gate. This kind of valve is called a rotating stem gate valve or a dark stem gate valve.