Breathing valve body can withstand 0.2Mpa pressure, no infiltration and deformation. Respiratory valve resistance to low temperature performance in the air relative humidity greater than 70%, the lowest temperature of -30 ℃, after 24 hours of freezing, the valve opening pressure in line with the working pressure requirements (allowing positive and negative pressure 20pa). GTQ-type vent valve plate parts action, high sensitivity, the action is completed, to ensure that the seal. Respiratory valve left enough space to ensure that the tank ventilation. Respiratory valve did not work pressure before: nominal diameter ≤ 150mm, the leakage ≤ 0.04m3 / h; nominal diameter ≥ 220mm, the leakage ≤ 0.4m3 / h; when the breathing valve to work pressure after: the valve plate immediately Open, to ensure the normal tank ventilation requirements. Main Specifications / Features and Performance: New flame arrester material used: cast iron, cast steel, stainless steel, aluminum alloy, good corrosion resistance. Valve plate, valve ring stainless steel PTFE material. Low temperature, antifreeze performance is good. The valve is installed on the fixed roof tank ventilation device to reduce oil evaporation loss, control the pressure of the tank. The valve has a large amount of ventilation, leakage, corrosion resistance, antifreeze performance. It can automatically adjust the pressure inside and outside the oil storage tank and so on. Gas flame arrester structure is simple, light weight, easy maintenance, easy installation. Hydraulic test qualified. Low-temperature antifreeze pass Qualified: at -42 ℃ for 2 hours, the pressure valve plate, vacuum valve plate and seal ring no deformation. Fully meet the standard requirements. Continuous operation at room temperature 36 ℃ for 72 hours, the action of 10000 times, the pressure valve plate, vacuum valve plate and the guide rod contact surface without any signs of wear and bruising, guide rod lifting no jam phenomenon.