全天候防火呼吸阀（QZF-89型）
QZF-89 Type Weather Breathing valve 

主要用途：Main uses:
   该阀是安装在固定顶罐上的通风装置，起减少油品蒸发损耗，控制储罐压力及阻止外界火焰传入的作用。
The valve is installed in the fixed roof tank ventilation, reduce the evaporation loss, control the tank pressure and prevent external flame spread.

主要特点：Main features:
该阀具有通风量大，泄漏量小，耐腐蚀等特点，并有静电接地线，使该阀与罐体保持等电位。该阀具有防冻性能，适用于寒冷地区。
The valve has a large amount of ventilation, a small amount of leakage, corrosion resistance and other characteristics, and static grounding wire, so that the valve and the tank to keep other potential. The valve has a freezing resistance, suitable for cold area.

主要技术参数：Main technical parameters:
操作压力：Operating pressure:
正压：+353pa(+36mmH₂O)    +980pa(+100mmH₂O)
负压：-295pa(-30mmH₂O)