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Because nitrogen is inert at room temperature and is not easy to breed bacteria, it is widely used in the preservation and storage of beverages, fruits, vegetables, cakes, tea, Chinese herbal medicine, pasta and other foods. It can fully maintain the original color, aroma and taste. The quality is significantly better than mechanical refrigeration.
For storage and preservation in the food field, the need for nitrogen is not the higher the purity, the better. During the preservation process of food, trace oxygen in the ambient gas can obtain a good preservation effect.
Nitrogen is chemically inactive and is a colorless and odorless inert gas that cannot be burned. Nitrogen is the main cost of air, accounting for 78%. Compared with other conventional gases, it is not easy to pass through the packaging film. Therefore, in the food industry, nitrogen generators are used to obtain nitrogen, which is used as the main filling gas in the modified atmosphere packaging system.

Food nitrogen making mechanism uses nitrogen for nitrogen-filled packaging, which is rapidly replacing traditional vacuum packaging and is used in the packaging of fried food, freshly sliced agricultural products, special cheese and fresh meat. Nitrogen-filled packaging can better maintain the taste, taste and nutrition of food, and its application field is expected to be further expanded.
The deterioration of food is mostly caused by oxidation reaction under the participation of O2, and promotes the reproduction of microorganisms and bacteria, resulting in food spoilage. As a suffocating inert gas, N2 has suffocating and inhibiting effects on bacterial reproduction in food. The purpose of using N2 is to eliminate O2, slow down the oxidation and respiration of food, and the solubility of N2 in water and oil is very small, and the adsorption effect of food on N2 is also small, so it can be used as a kind of better. Gas for food preservation and preservation.
In addition, nitrogen-filled packaging can also play a good role in protecting the shape of the food inside: prevent crispy and fragile food from being crushed; avoid the unbalanced internal and external pressures that cause the packaged food to be bonded together by pressure, making its texture Hardening; even food with irregular shapes can keep the appearance of the package body and reduce the deterioration of the food due to the damage of the packaging material caused by surface folds.
Nitrogen quality is the key: Gas quality is an important factor in modified atmosphere packaging of food. Packaging has strict regulations on the purity of N2, the gas used must reach pure nitrogen grade, that is, food grade, and the content of impurity components in the gas must be lower than the safety limit standard that does not endanger human health. The main impurity components contained in N2 are O2, CO, CO2, CH2 and H2, etc. The national standards for pure nitrogen have specific regulations on their content.

3. Factors Affecting the Stability of Nitrogen Generators
Nitrogen generator is a high-tech product involving machinery, electricity and instrumentation, and the stability of the equipment is particularly important in long-term use. It is not difficult to see from the composition of the nitrogen generator that the stability is affected by the following two points:
1. Control valve: For the pressure swing adsorption nitrogen generator, the valve [ ] must have the following properties:
a. Good material performance, absolutely no air leakage;
b. Complete the opening or closing action within 0.02 seconds of receiving the control signal; c. Can withstand frequent opening and closing to ensure a long enough service life; 2. Under the normal use condition of the valve fault source, each programmable valve will be operated at every One cycle (about 120 seconds) must be turned on and off - once a year. According to the calculation of 300 working days per year, the nitrogen generator operates continuously 24 hours a day, and the adsorption and desorption cycle is 4 minutes. Then each valve "] needs to be opened and closed every year. It has been closed more than 200,000 times. As long as one of the valves fails, it will affect the normal operation of the entire equipment. Therefore, the continuous service life of the valve [ ] is the most important part of the stability and reliability of the nitrogen generator.