tive pressure system with temperature 200 . When the netative pressure in the container exceeds the allowable value, the valve will open automatically and absorbs air When the netative pressure in the containerreaches the allowable value, the valve willclose automatically so as to protectthe equipmentand the system. Itis to be installed in normalnon-negative pressure systems. When the discharge valve ofthe containerand system has not opened,which produces the negative pressure, this valve will open TFA72W is applicable in nega-automatically.