The chromatographic separation method is adopted to continuously produce high-purity nitrogen. The gas supplied by the air compressor is introduced into the molecular sieve. Oxygen, carbon dioxide, water and other impurities are removed through the molecular sieve. Only nitrogen is allowed to pass through the molecular sieve and enter the gas storage tank. The tank can be used directly after adjusting the appropriate pressure and flow rate. This is the working principle of the laboratory liquid nitrogen machine.

1. Technical advantages of laboratory liquid nitrogen machine

　　 1. Easy to operate

　　 Free of the labor of transporting steel cylinders, saving the pain of transporting steel cylinders, as long as the power switch is turned on, nitrogen can be produced, which can be used continuously or intermittently, and the nitrogen content is stable and does not attenuate.

　　2, high-tech

　　The electrolytic cell adopts a vertical single-layer double cathode. The new membrane separation technology uses a PCA carrier and a precious metal catalyst in the catalyst layer, which improves the catalytic efficiency of the electrolytic cell, with large output and high nitrogen purity. After more than 100 hours of high-voltage and high-current aging test, the performance and working state of the electrolytic cell are very stable.

　　3, low nitrogen production humidity

　 The laboratory liquid nitrogen machine adopts high molecular weight permeation separation technology and effective dehumidification device, which can reduce the original humidity and automatically drain after shutdown. With metal polymer dehumidification and two-stage adsorption, the purity of nitrogen is significantly improved.

　　4, program control

　　The control system of the machine uses a chip. All work processes are completed under program control. Automatic constant pressure, constant flow, and nitrogen flow can be fully automatically adjusted to 0-300ml/min according to the amount of use.

　　5, three-stage catalysis

　　 In addition to the secondary catalyst in the electrolytic cell, there is another three-pole catalysis. The catalyst is a new type of noble metal, so that the oxygen content of the output nitrogen is less than 3ppm.

　　 2. After using the laboratory liquid nitrogen machine for a period of time, it was found that the silicon in the drying tube was discolored from bottom to top, and the silicon needs to be replaced if it exceeds a certain height. The procedure is as follows:

　　 1. Turn the drying lid to the direction of the picture until it turns completely. It is strictly forbidden to do this work when you are under pressure.

　　 2. Remove the inner tube of the dry tube upwards, remove the cotton swab, and pour silica gel.

　　3. It is best to put in new (or dry) silica gel, and do not exceed the small vent near the nozzle. Cover with cotton, cotton yarn or other sundries can not be buried in the end of the drying nozzle (otherwise, do not leak). Then, put the inner tube into the outer tube of the drying tube.

　　4. Tighten the cover of the drying tube, use soapy liquid to detect the leak and start the machine.

　　 5. The replacement method of activated carbon is the same as that of silica gel.