Nitrogen sealing device is divided into nitrogen device and nitrogen sealing device nitrogen device, by the control valve, actuator, pressure spring, pilot, pulse self-nitrogen valve (structure) Chong tube and other components. Mainly used to maintain the container top of the protective gas (usually nitrogen) constant pressure to avoid direct contact with the material in the container and the air, to prevent volatile materials, oxidation, and container safety. Especially suitable for all kinds of large tank gas seal protection system. The product has energy-saving, sensitive action, reliable operation, easy operation and maintenance. Widely used in petroleum, chemical and other industries. Nitrogen device, will be located at the top of the tank to take the pressure of the medium through the guide tube into the detection mechanism, the medium in the detection element to produce a force and with the spring, pre-tension phase balance. When the tank pressure is reduced below the pressure set point for nitrogen supply device, the balance of destruction, so that the pilot valve, open, so that the valve before the gas through the valve, throttle, into the main valve actuator, the lower membrane When the pressure inside the tank rises to the pressure set point of the nitrogen supply device, the pilot valve core is closed due to the preset spring force. Due to the spring action in the main valve actuator Turn off the main valve and stop supplying nitrogen. Nitrogen device, the device uses the internal feedback structure, the media directly through the valve cover into the detection mechanism, the media in the detection element to produce a force with the pre-set spring preload balance. When the pressure in the tank rises above the pressure set point of the nitrogen release device, the balance is destroyed and the valve plug is moved upward to open the valve to release nitrogen to the outside. When the pressure in the tank drops to the pressure set point of the nitrogen release device, Due to the preset spring force, close the valve.