What is the working principle of the gas seal in storage tanks?

A tank gas seal is a device used to prevent gas leakage and control pressure. The gas seal is mainly composed of a pressure control valve, a detector, exhaust pipelines, etc. The working principle is as follows: 1. When the pressure inside the tank exceeds the set value, the pressure control valve opens to release the excess gas from the tank. 2. The detector monitors the pressure inside the storage tank and sends information back to the control system. 3. The control system adjusts the opening degree of the pressure control valve based on the feedback from the sensors, in order to maintain the pressure inside the storage tank within the set range. 4. If the pressure control valve fails to function properly or if the pressure inside the tank rises abnormally, the safety valve in the exhaust pipeline will open automatically to release the gas into a safe area. The operation of the relevant valves is as follows: 1. Pressure control valve: According to the instructions from the control system, it adjusts the gas flow by opening and closing to control the pressure inside the storage tank. 2. Safety valve: It opens automatically when the pressure exceeds the set value, releasing the gas to a safe area. In summary, the working principle of the gas seal in storage tanks is to control and release the gas pressure inside the tank through the regulation of pressure control valves and safety valves, as well as through the cooperation of devices such as monitors and exhaust pipelines. .

A nitrogen sealing system generally consists of a stand-alone pressure regulator and a breather valve.

The self-acting control valve used in the gas seal pipeline shown in the diagram automatically adjusts to maintain the pressure inside the tank at a set value. I’m not sure why two paths for gas seal air are provided to enter the tank; those who know the reason could please share their insights.