The valve type valve indicated above device, the realization of automatic termination of material from pressure vessel, boiler, or other system if the temperature or pressure exceed predetermined limit. They are more setting named PSV C pressure relief valve. First use of these type of valve in steam boiler, this is the industrial revolution long age. Without these equipment, early boiler is susceptible to accidental explosion.
Simple structure of the earliest use of weight in order to grasp the relief valve pressure cooker pressure; Today still use this design. Are easily confused with these, they also prone to accidental release. Less prone to valve sudden acceleration may contain steam pressure, use a spring, still can improve down