Spring loaded breathing valve is an important device to make the pressure of oil storage tank when it is closed. It should meet the requirements of three typical working conditions of the tank, that is, no air leakage when the oil tank is closed within the specified pressure range, so as to reduce the loss of oil vapor volatilization; when the gas pressure in the oil tank reaches the specified value and the ambient weather changes slowly and normally It can ventilate with small flow rate, and can ventilate resistance with large flow rate when the temperature of gas in the tank changes sharply due to sudden changes of ambient weather.
At present, there are many kinds of classification methods for the breathing valve. According to the relative position of suction valve axis, it can be divided into coaxial type and double axis type; according to the ambient temperature, it can be divided into normal temperature type and antifreeze type; according to the movement restriction of valve disc, it can be divided into guide rod type and rotary arm type. Although there are many names and different shapes of the breathing valve, the basic valve type is the same, which is composed of the valve seat and the valve disc covered in the valve port.
