The nominal pressure meaning of pneumatic valve

( 公称压力) , said symbol PN, under a certain temperature applications allow maximum working pressure. Control valve for carbon steel body, refers to the application under 300 ℃ maximum allowable working pressure; For cast iron valve body, the point at which the application under 120 ℃ maximum allowable working pressure; Control valve for stainless steel body, refers to the application under 250 ℃ maximum allowable working pressure. When working temperature, the body pressure is reduced. For example, nominal pressure is 6. 4MPa（ PN64) Carbon steel valves, pressure of 5 to 300 ℃. 2 mpa, 400 ℃ when the pressure of 4. 1 mpa, to 450 ℃ when the pressure of 2. 9MPa。 Control valve, therefore, the determination of nominal pressure not only according to the maximum working pressure, still need according to the maximum operating temperature and material characteristics, not only meet the nominal pressure is greater than the pressure of work.