The principle and function of the fire stop breathing valve at the end of the pipe:
The fire resistant breathing valve at the pipe end is composed of pressure valve and vacuum valve,which is installed on the vent pipe of cargo oil tank.It can automatically open and close with the change of positive and negative pressure of oil and gas in cargo oil tank,so as to keep the pressure difference between inside and outside the cargo oil tank within the allowable range.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;when the medium is added to the tank,the pressure of the upper gas space in the tank will be increased;when the operating positive pressure of the breathing valve is reached,the pressure valve will be opened,and the gas will escape from the vent of the breathing valve,so that the pressure in the tank will not continue to rise;the atmosphere outside the tank will be opened and exhaled Negative pressure valve disc of suction valve.
As an important accessory to protect the oil tank,the pipe end fire stop breathing valve is installed on the top plate of the oil tank and consists of pressure valve and vacuum valve.Its function is to keep the tightness of oil tank and reduce the evaporation loss of oil to a certain extent.When necessary,it can automatically ventilate,adjust and balance the internal and external pressure of the oil tank,so as to protect the oil tank.When the oil and gas pressure in the tank is greater than the allowable pressure of the oil tank,the oil vapor escapes through the pressure valve,and the vacuum valve is closed;when the oil and gas pressure in the tank is less than the allowable vacuum degree of the oil tank,fresh air enters the tank through the vacuum valve,and the pressure valve is closed,and the allowable pressure(or vacuum pressure)is controlled by the weight of the regulating plate.
The tube end fire stop breathing valve can not only maintain the pressure balance of the tank,but also reduce the volatilization and loss of the medium in the tank.
