Is the same, the relief valve is also called the pressure relief valve, is to protect with valve, it's under external force open-close part in a normally closed state, when the equipment or piping within the medium pressure increases, more than a specified value automatically when open, through a discharge medium system to prevent the pipeline or equipment within the medium pressure in excess of the prescribed value. Relief valve belong to automatic valve class, mainly for the boiler, pressure vessel and piping, control pressure shall not exceed the specified value, to protect personal safety and equipment operation plays an important role.