In today's valve family, gate valve is relatively widely used. Among them, wedge type double gate valve and wedge type elastic gate valve are the most widely used, because they have the best sealing effect. Everything has its advantages and disadvantages. It is because of its good sealing effect that the pressure in the middle chamber will rise abnormally in some occasions.

Abnormal boost pressure can occur in many gate valve applications. Many industrial system media change from cold state to hot state after startup; The wedge is closed in cold state and opened in hot state. Therefore, if no measures are taken for the system, the damage to the system caused by abnormal pressure rise is almost inevitable, which will damage the gate valve itself, system safety and control process.

In order to fundamentally eliminate the abnormal boost in the middle cavity, we can start from the aspects of design, installation, and commissioning. There are three plans for your reference:

1. The fundamental solution to the abnormal pressure increase in the middle cavity is to balance the pressure in the middle cavity. It is the most economical and effective solution to open a pressure relief hole inside the valve;

2. For the valves that have been shipped out of the factory, the pressure in the middle cavity can be reduced by installing an external bypass and a peripheral pressure relief valve;

3. Install a special pressure relief valve outside the middle cavity of the gate valve.

Abnormal overpressure is an invisible killer of gate valves, which seriously threatens the safe operation of equipment and systems, and must be paid attention to. For gate valves, especially high temperature, high pressure, and large diameter gate valves, the occurrence of abnormal overpressure must be considered during design and installation, and necessary preventive measures must be taken.