A21H series safety valves are suitable for air, ammonia, petroleum gas and other media equipment or pipelines whose working temperature is less than 200 C; A21W-P, R type safety valves are suitable for corrosive gas or liquid equipment or pipelines whose working temperature is less than 200 C; KA21Y type safety valves are suitable for liquefied petroleum gas whose working temperature is less than 100 C.
Safety valve is an overpressure protection device on pressure equipment (such as containers and pipes). When the equipment pressure rises to a predetermined value, the safety valve automatically opens and relieves pressure to prevent the equipment pressure from continuing to rise. When the pressure decreases to the specified value, the safety valve closes automatically in time to prevent the mass loss of media in the equipment.