The gate valve is a shutter of the opening and closing member. The direction of movement of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully open and fully closed, and cannot be adjusted and throttled.
List of content for this article：
1.Definition of industrial gate valve,
2.The seal of industrial gate valve,
3.The use of industrial gate valve.
Definition of industrial gate valve
The gate valve is sealed by the contact between the valve seat and the gate. Usually, the sealing surface will be welded with metal material to increase wear resistance, such as surfacing 1Cr13, STL6, stainless steel, and the like. The gate has a rigid gate and an elastic gate. According to the gate, the gate valve is divided into a rigid gate valve and a flexible gate valve.
The direction of movement of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully open and fully closed, and cannot be adjusted and throttled. The gate has two sealing faces. The two sealing faces of the most common mode gate valves form a wedge shape. The wedge angle varies with the valve parameters, usually 5°, and the medium temperature is not 2°52'. 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 improve its processability and make up for the deviation of the sealing surface angle during the machining process. The board is called a resilient shutter.
The seal of industrial gate valve
When the gate valve is closed, the sealing surface can be sealed only by the medium pressure, that is, the sealing surface of the ram is pressed against the valve seat on the other side by the medium pressure to ensure the sealing of the sealing surface, which is self-sealing. Most of the gate valves are forced to seal, that is, when the valve is closed, the external force is forced to press the gate to the valve seat to ensure the sealing of the sealing surface.
The gate of the gate valve moves linearly with the valve stem, which is called a rising stem gate valve. Usually, there is a trapezoidal thread on the lifting rod, and the rotary motion is changed into a linear motion by the nut at the top end of the valve and the guide groove on the valve body, that is, the operating torque is changed to the operating thrust. When the valve is opened, when the lift height of the gate is equal to 1:1 times the diameter of the valve, the passage of the fluid is completely unblocked, but this position cannot be monitored during operation.
The use of industrial gate valve
In actual use, the apex of the valve stem is used as a mark, that is, the position where the valve is opened, as its fully open position. In order to consider the temperature change, the lock phenomenon occurs, usually at the position of the opening to the apex, and then back to 1/2-1 circle as the position of the fully open valve. Therefore, the fully open position of the valve is determined by the position of the shutter, that is, the stroke. In some gate valves, the stem nut is arranged on the gate plate, and the rotation of the hand wheel drives the valve stem to rotate, and the shutter is lifted. This valve is called a rotary lever gate valve, or non-rising stem gate valve.