With double takeover breathing valve (with inhalation, with exhaled, fire retardant) take over the breathing valve Crude oil, gasoline, kerosene, aviation oil, light diesel oil, aromatic hydrocarbons, propylene, nitrogen and other fixed top-type storage tank on the indispensable main safety equipment, Play a role in preventing evaporation loss and protecting the tank from being damaged when overpressured or under vacuum. With take over (fire resistance) breathing valve is to maintain the tank pressure balance, reduce the volatile media, energy-saving security products. Take over the breathing valve is installed in the fixed roof cans on the ventilation and fire retardant devices, can play to reduce oil evaporation loss, control the pressure of the tank balance and control the role of the flame. It can automatically adjust the pressure inside and outside the tank and negative pressure automatically. The series of breathing valve with electrostatic protection device, making the valve moment and the tank to maintain the same potential.