Valve safety is a device designed to protect other equipment (pressure vessels, boilers, heat exchangers, plumbing, compressors, etc.) by opening automatically at a specified pressure to prevent damage due to overpressure. Process and storage system used.
Excessive pressure depends on the standards followed and the specific application. The pressure at which the safety valve must operate can be based on ASME and ANSI.
Lifting
When the pressure inlet increases from the constant pressure of the safety valve, the disc begins to lift its seat. Then the spring starts to compress.
As the pressure increases, the disc continues to lift. To achieve full low pressure opening, the disc arrangement must be specially designed to open quickly.
As the disk begins to rise and liquids enter the chamber, most of the coating is exposed to liquid pressure. As the fluid pressure increases, the safety opens even faster.
coming back
The safety of the valve has to adjust the position of the valve after reducing the pressure. But because the larger disc area is exposed to the liquid, the valve does not close until the pressure drops below the initial setting pressure. The distinction between constant pressure and return pressure is called “impact”.
Uses of valve safety :
Pressure safety valve (PSV) is commonly used to protect against overpressure. This is one of the approved ways of pressure protection devices.
Safety valves should be installed wherever there is a maximum operating pressure per system pressure (MAWP). Valve safety is also used to prevent damage to equipment due to excessive pressure during process activities.
safety is mainly used in the following places:
- Boiler
- Super Hits
- Reheater output (HRH)
- Reheater input (CRH)
- Steam soot steam line
- Pressure reducing stations
- Pressure tanks such as the Blowdown tank
The difference between valve safety and valve relief
The names “rigidity” and “relief” are often used interchangeably, but for compressible fluids (including vapors and other gases), relief is not thought to be used.
Compressible fluids require rapid pressure relief.
Valves for non-compressible liquids are liquids such as water and oil. Immediate complete drainage of the current is not necessary because a very small current dramatically reduces the overpressure, thus opening and closing the socket and seat very slowly.