Hazards of abnormal pressure rise of gate valves
the system medium changes from cold to hot after startup; The ram is closed in the cold state and opened in the hot state. Therefore, if no measures are taken for the system, the damage caused by abnormal pressure rise to the system is almost inevitable, and there are three hazards:
(1) Damage to the valve itself
The strength of the valve housing, bonnet, and stem parts is generally designed based on the nominal pressure of the valve. When abnormal pressure increases, the opening pressure will increase exponentially, resulting in a doubling of the service stress of the relevant parts. When the actual stress of the material exceeds the allowable stress, fracture damage will occur at the highly stressed parts, resulting in the valve being unable to open, and the entire valve will be damaged or scrapped.
(2) Damage to system security
Obviously, pressure bearing parts such as shells and valve caps can be very dangerous when overpressure occurs. Once overpressure occurs, the weak parts may first undergo perforation, causing media leakage; The packing and self sealing ring parts are often flushed out by high-pressure fluid, causing a large amount of media leakage. When the medium is high-temperature gas, toxic gas, or harmful gas, it can become even more serious, and even cause injury to equipment and personnel.
(3) Cause significant losses to the production control process
The normal opening and closing of valves is the key to various industrial process control. Once this control cannot be achieved, the system must be shut down for maintenance, which will cause huge direct or indirect losses