What is the working principle of the breathing valve

2020-09-15 11:56:38

The breathing valve is composed of pressure valve and vacuum valve, which is installed on the top of storage tank and can automatically open and close with the change of positive and negative pressure of oil and gas in the outlet pipe, so as to keep the pressure difference between inside and outside the storage tank within the allowable range.

The breathing valve is an energy-saving product to maintain the pressure balance of the storage tank and reduce the medium volatilization. The breathing valve makes full use of the pressure bearing capacity of the storage tank to reduce the medium discharge. Its principle is to control the positive exhaust pressure and negative suction pressure of the storage tank by using the weight of the positive and negative pressure valve disc. When the medium is drawn out from the tank, the pressure of the upper gas space in the tank will drop and the negative pressure of the breathing valve will be reached The external atmosphere will open the negative pressure valve disc of the top opening breathing valve, so that the external gas enters the tank, so that the pressure in the tank will not continue to drop, and the air pressure inside and outside the tank can be balanced to protect the storage tank device.


1. When the pressure of the medium in the tank is within the control operating pressure range of the breathing valve, the breathing valve will not work to maintain the tightness of the oil tank;

2. When the medium is added into the tank to increase the pressure of the upper gas space in the tank and reach the positive operating pressure of the breathing valve, the pressure valve will be opened and the gas will escape from the breathing valve outlet, so that the pressure in the tank will not continue to rise;

3. The atmosphere outside the tank will open the negative pressure valve disc of the breathing valve.


1. For the requirements of installation position and temperature range, all-weather breathing valve should be selected in cold area, and pipeline type breathing valve should be selected for pipeline installation.

2. The control pressure of mechanical breathing valve should be adapted to the relevant pressure bearing capacity.

3. The specification of mechanical breathing valve (flange diameter) should meet the requirements of large flow of breathing gas in and out of oil tank.

One is to breathe or inhale when the pressure is reached; the other is designed to breathe only but not inhale, which can be understood to be replaced by two one-way valves with appropriate pressure.

The two kinds of breathing valves are similar to one-way check valves. They can only exhale outwards and cannot inhale inward. When the pressure in the system increases, the gas will be vented through the breathing valve to meet the constant pressure of the system. For the storage tank of toxic substances, there is no breathing valve, and activated carbon filter can be added to treat the device.

Breathing valve is generally used in atmospheric or low-pressure storage tank, that is, only atmospheric and low-pressure storage tank can have breathing discharge (steam recovery system is often used on low-pressure tank), and high-pressure storage tank has no discharge, no breathing loss and work loss.

The main discharge of fixed roof tank is divided into respiratory loss (small breathing emission) and working loss (large breathing emission).