Safety valves play a vital role in piping or equipment, and their main function is to prevent the medium pressure from exceeding the preset safety range, thus ensuring the safe operation of the system. Safety valve is essentially a protection valve, its closing part is normally closed, once the equipment or pipeline inside the medium pressure rises and exceeds the safety setting value, the safety valve will automatically open, release part of the medium to the outside of the system, in order to prevent the pressure from continuing to rise and cause danger.
Safety valve belongs to a kind of automatic valve, widely used in boilers, pressure vessels and various piping systems. Its core role is to control the pressure does not exceed the prescribed value, the safety of personnel and the normal operation of the equipment to provide critical protection.
According to the opening height of the safety valve flap, we can categorize it into micro-opening safety valve and full-opening safety valve. Micro-opening safety valve opening stroke is relatively small, usually no more than 5% of the minimum discharge throat caliber (i.e., ≤ 0.05d0); while the opening height of the full-opening safety valve is larger, can reach 25% of the minimum discharge throat caliber (i.e., ≤ 0.25d0).
From the structural form, the safety valve can be divided into pendant, lever, spring and pilot (also known as pulse). From the structure of the valve body, safety valves can be divided into closed and unclosed type. Closed safety valves are capable of completely directing the released medium to a designated safe location, and are usually used to handle toxic or corrosive media. For air and steam systems, however, unenclosed safety valves are mostly used.
When selecting safety valves, we need to determine the appropriate model according to the actual working pressure requirements. Especially for spring-loaded safety valves, there may be a variety of working pressure levels available within the same nominal pressure (PN) range. Therefore, when ordering, in addition to stating the model number, name, media type and temperature requirements of the safety valve, it is also necessary to specify the sealing pressure of the valve body, otherwise the supplier may supply according to the maximum sealing pressure.
In summary, safety valves are indispensable safety components in industrial systems, and their proper selection and use are essential for personnel safety and normal equipment operation.