Equipment introduction and parameters

Thermal properties of liquid nitrogen and characteristics of liquid nitrogen quick freezer

At atmospheric pressure, when liquefied nitrogen changes from liquid to gas, the average latent heat of evaporation to be absorbed per kilogram of liquefied nitrogen is 199.29 kJ, and 1.05 kJ of heat is absorbed for every 1 °C increase, and the heat absorbed when the temperature rises from -196 °C to -20 °C is 185 kJ. Liquid nitrogen quick-freezing is to take advantage of the ultra-low temperature absorption characteristics, using liquid nitrogen dispersion technology to disperse liquid nitrogen into gas directly to the desired seafood. At this time, the temperature difference is as high as 200 ℃ or more, which can carry out strong heat exchange and can make seafood instantly. For freezing, the entire freezing process can generally be completed in about 10 minutes, which is several times faster than the ordinary freezing method. Due to the short freezing time, the generated ice crystals are very small, and the freezing speed is greater than the speed of vapor penetration inside and outside the cell. Ice crystals are generated inside and outside the cell at the same time, which has no destructive effect on the cells, so the original color, aroma, taste and freshness can be maintained after thawing. State, is the first-class technology recognized by all countries in the world today.

Technical features of liquid nitrogen quick freezer:
1. Intelligence: The operating system is controlled by the PLc microcomputer, operated by a touch-type LCD screen, and controlled by the PLc, with automatic controls such as energy regulation, fault diagnosis, protection monitoring, etc., and the functional data is clear at a glance;
2. Environmental protection: Use liquid nitrogen as the cold source. Liquid nitrogen is separated from the air. After the cold source of liquid nitrogen is used, it is returned to the air, which will not cause air pollution and fully meet the requirements of environmental protection.
3. High efficiency: Since the temperature of liquid nitrogen is -196°C, the temperature in the tunnel can reach -130°C, and it can quickly exchange heat with the frozen product, and the frozen product can meet the requirements in 20-40 minutes.

Equipment composition:

1. Equipment main body-- box, box door, bracket, mesh belt, sprocket, electric control box and other materials all

304stainless steel;

2. Insulation material--The insulation layer is filled with special materials for ultra-low temperature insulation, and the exterior

is double-sided.2mm thick stainless steel plate, good thermal insulation performance, easy to clean and ensure food hygiene

and safety;

3. Door body seal -- double seal, special low temperature resistant silicone rubber imported from France, door seal.The seal

is equipped with an anti-freeze heating system, which can ensure that the box door can be opened freely;

4. Liquid nitrogen system -- including insulation pipes, control valves, nozzles, distributors, liquid nitrogen using multi-point

Jet injection ensures the uniformity of the temperature of the trap body;

5. Air circulation system in the box -- including motor, fan, air distribution device;

6. Electrical control system--variable program controller, touch screen, alarm indication, AC connection

Contactors, intermediate relays, rotary switches, etc.