Breathing valve is divided into two kinds:
The first is to reach a certain pressure, the call or suction; the other is designed to simply call not suction, can be understood as a one-way valve with two appropriate pressure to replace.
The second kind of breathing valve similar to one-way non-return valve, it can only breathe out, not inward inspiratory, when the system pressure increases, gas through the respiratory valve outward vent to ensure constant system pressure. For the storage tank of toxic substances, is not the breathing valve, or with activated carbon filter processing device.
Breathing valve is generally used in normal pressure or low-pressure tank, namely only atmospheric and low pressure storage tank to tank breathing emissions (in the low pressure tank often steam recovery system), the pressure storage tank no emissions, no respiratory losses and the loss of work.
The main discharge of the fixed roof tank is divided into respiratory loss (small breathing) and loss of work (big respiration).
