What Is The Working Principle Of The Breathing Valve?
Jul 16, 2019| What is the working principle of the breathing valve?
It consists of a pressure valve and a vacuum valve. It is installed on the top of the tank and can automatically open and close with the change of positive and negative oil and gas in the pipe, so that the pressure difference between the inside and outside of the tank can be kept within the allowable value range.
The breathing valve is a safe and energy-saving product that maintains the pressure balance of the tank and reduces the volatilization of the medium. The breathing valve makes full use of the pressure capacity of the tank itself to reduce the medium discharge. The principle is to control the row of the tank by the weight of the positive and negative pressure discs. Positive gas pressure and negative suction pressure; when the medium is taken out of the tank, the pressure of the gas space in the upper part of the tank is lowered, and when the negative pressure of the operation of the breathing valve is reached, the atmosphere outside the tank will open the top of the negative pressure valve of the breathing valve. Open, so that the outside air enters the tank, so that the pressure inside the tank does not continue to drop, and the pressure inside the tank is balanced with the outside of the tank to protect the safety device of the tank.
principle:
1. When the pressure of the medium in the tank is within the control operating pressure range of the breathing valve, the breathing valve does not work, and the airtightness of the oil tank is maintained;
2. When the medium is replenished into the tank, the pressure in the upper gas space of the tank is raised, and when the positive pressure of the breathing valve is reached, the pressure valve is opened, and the gas escapes from the breathing valve outlet, so that the pressure in the tank is not continued. Increase
3. The atmosphere outside the tank will open the negative pressure valve disc of the breathing valve.
Selection
1. For the requirements of the installation position and the temperature range, for example, all-weather breathing valves should be used in cold areas, and pipeline breathing valves should be used in the pipelines.
2. The control pressure of the mechanical breathing valve should be compatible with the relevant pressure bearing capacity.
3, the specifications of the mechanical breathing valve (flange diameter) should meet the requirements of the oil tank's large inflow and outflow breathing gas flow.
The species is called or sucked when a certain pressure is reached; the other is designed to be purely no-sucking, which can be understood as replacing it with two check valves of appropriate pressure.
The second type of breathing valve is similar to a one-way check valve. It can only exhale outward and cannot inhale. When the pressure in the system rises, the gas will vent outward through the breathing valve to ensure that the pressure of the system is constant. For storage tanks containing toxic substances, there is no breathing valve, and an activated carbon filter can be added to treat the device.
Breathing valves are generally used on normal or low pressure storage tanks, that is, only normal pressure and low pressure storage tanks have respiratory emissions (there is often a steam recovery system on low pressure tanks), high pressure storage tanks have no emissions, no respiratory losses and work losses. .
The main emissions of fixed top tanks are divided into respiratory losses (small respiratory emissions) and work losses (large respiratory emissions).