Atmospheric and low pressure storage tanks are common equipment in the process industry。During the use of normal pressure and low pressure storage tanks, due to the change of the liquid level in the tank or the change of the external temperature, the gas in the tank will expand or contract, and the pressure of the gas phase in the tank will also fluctuate。The fluctuation of gas pressure is easy to lead to tank overpressure or vacuum, which will cause tank overpressure or low pressure collapse。

In order to prevent unstable conditions such as overpressure or negative pressure in the tank, the process design is usually installed on the top of the tankBreather valveTo maintain the air pressure balance of the storage tank to ensure that the storage tank will not be damaged under overpressure or vacuum, protect the safety of the storage tank, reduce the volatilization and loss of the materials in the storage tank, and play a certain role in promoting safety and environmental protection。

Common standards for breathing valves are:

SY/T 0511.1-2010 "Oil storage tank accessories Part 1: Breathing Valve"

TB/T 3319-2013 "Breathing Safety Valve for Railway tank Cars"

QC/T 1064-2017 "Road Transport of Flammable liquid Dangerous Goods tank vehicle Breathing Valve"

DIN EN 14595-2016 "Pressure and vacuum breathing valves for the operation of tanks for the transport of dangerous Goods"