Ultra low temperature freezer working principle
Ultra-low temperature freezer are often used in factory laboratories, scientific research institutes and other places to store test products and test product performance. Ultra-low temperature freezer at minus 60 degrees Celsius can be used to store tuna, plasma, biological materials, vaccines and reagents, and can also be used for electronic devices And low temperature test of special materials.
Ultra-low temperature refers to a temperature lower than low temperature. In physics, it refers to the temperature of liquid air below -263 degrees Celsius. Ultra-low temperature refrigerator is a kind of equipment manufactured using ultra-low temperature technology. In fact, the so-called ultra-low temperature freezer are usually referred to as ultra-low temperature storage boxes, ultra-low temperature freezers, and ultra-low temperature storage boxes. Ultra-low temperature freezer generally use two-stage refrigeration. The refrigerant of the second stage is R-12, and the design pressure is 400ppsi and the low pressure is 90ppsi. The second stage refrigerant is R-503 (8.50z) and R-290 (0.70z). The designed high and low pressure are 300ppsi.
Working principle of ultra-low temperature freezer
The refrigeration system of the ultra-low temperature refrigerator basically adopts the working principle of cascade refrigeration, and two fully enclosed compressors are used as high and low temperature compressors. The copper tube of the low-temperature evaporator is directly attached to the outside of the inner box in the form of a coil, and the gap between the coil and the wall of the box is filled with thermally conductive glue to increase the heat exchange effect. The condensing evaporator is a shell-and-tube structure with four threaded copper tubes inside, and a countercurrent heat exchange method.
The low-temperature system is also equipped with a gas heat exchanger, which allows the low-pressure gas from the evaporator to exchange heat with the high-pressure gas before entering the condensing evaporator, which not only reduces the heat load of the condensing evaporator, but also makes full use of the heat .
Ultra-low temperature freezer refrigerant and cooling method
Adopt fluorine-free environmentally friendly refrigerant and mixed refrigerant to ensure that the maximum cooling effect can be obtained under different cooling temperature requirements.
Precautions for the use of ultra-low temperature freezer
Correct maintenance and use are particularly critical to prolong the service life and normal use of ultra-low temperature freezer, so there are many precautions when using ultra-low temperature freezer. The key thing for the ultra-low temperature refrigerator is to control the temperature of the refrigerator. The temperature inside the refrigerator needs to be between 5 and 32 degrees Celsius, with a relative humidity of 80%/22°C. The refrigeration temperature of the refrigerator is generally set at minus 60 degrees Celsius, and it takes about 6 hours when the refrigerator changes from 20 degrees Celsius to minus 80 degrees Celsius.
Do not freeze strong acids or corrosive things inside the ultra-low temperature refrigerator. When the refrigerator starts to work, it is necessary to ensure that the refrigerator's power supply voltage is stable. In the event of a power failure, the power switch and battery switch on the back of the refrigerator must be turned off, and the switch must be turned on when the power supply is restarted. In summer, you need to adjust the temperature of the refrigerator to about minus 70 degrees Celsius, not too low, and maintain good indoor ventilation and heat dissipation, and pay attention to the temperature of the surrounding environment not to exceed 30 degrees Celsius.
