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

主要用途：Main uses:
   該閥是安裝在固定頂罐上的通風裝置，起減少油品蒸發損耗，控制儲罐壓力及阻止外界火焰傳入的作用。
The valve is installed in the fixed roof tank ventilation, reduce the evaporation loss, control the tank pressure and prevent external flame spread.

主要特點：Main features:
該閥具有通風量大，泄漏量小，耐腐蝕等特點，并有靜電接地線，使該閥與罐體保持等電位。該閥具有防凍性能，適用于寒冷地區。
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.

主要技術參數：Main technical parameters:
操作壓力：Operating pressure:
正壓：+353pa(+36mmH₂O)    +980pa(+100mmH₂O)
負壓：-295pa(-30mmH₂O)