Effect:
It makes full use of the bearing capacity of the oil tank itself to reduce the oil vapor emission, and its principle is to use the weight of the valve disc to control the positive pressure and the negative pressure of the oil tank. When the tank of gas pressure in mechanical breathing valve control pressure range, breathing valve does not move, keep the tightness of the oil tank. When the pressure in the gas space in the tank rises to positive pressure breathing valve control, pressure valve is pushed open, gas is escaping from the tank, tank pressure not continues to increase in; when the pressure in the gas space in the tank drops to the breathing valve of negative pressure control, air outside of the tank top open the vacuum valve and into the tank, the pressure in the tank is on the decline.
Mechanical breathing valve selection:
1. The requirements of the installation location and temperature range of requirements, such as the cold area should choose all-weather breathing valve, and installed in the pipeline should use the pipeline type of breathing valve.
2. Mechanical breathing valve control pressure should be related to the ability to adapt to the pressure.
3. Mechanical breathing valve specifications (flange diameter) should meet the maximum oil inlet and outlet gas flow requirements.
