This valve is to be used in equipments and pipelines of air, petroleum, water or other mediums with
operation temperature no higher than 300℃, while A47H is to be used in equipments and pipelines of
steam, When the pressure in equipment or pipeline exceeds allowed value, the valve will open
automatically and fully discharge, then close again when the pressure lowered to the regulated value
soaps to ensure the safe operation of the equipment or pipeline.