Classification and Operation of ULT Freezer

Ultra-low temperature freezer (ULT freezer) can be divided into 3 kinds according to the temperature range:

1 -60 degree freezer suit for tuna preservation, electronic devices, special materials at low temperature and stored plasma, biological materials, vaccines, reagents.

2 -86 degree ultra low temperature freezer (ULT freezer), widely used in biological products, chemical reagents, serum, vaccines, bacteria, biological samples such as cryopreservation.

3 -105 degree to -150 degree ultra-low temperature freezer (ULT freezer) for research institutes, metal processing, biotechnology, blood banks, hospitals, epidemic prevention system, university laboratories, military enterprises.

Ultra-low temperature refrigerator (ULT freezer) generally using two stage cooling system, the first stage refrigerant R-12 (23.0 oz, 1oz = 28.349523g), high pressure of design pressure is 400ppsi (1ppsi = 6.89476X103Pa), low pressure is 90ppsi. Second stage refrigeration condensing and the first stage cooling evaporators are put together; the second stage refrigerant R-503 (8.5 oz), and R-290 (0.7 oz) mixture, high pressure of design pressure is 300ppsi. Temperature probe is thermistor, different temperatures displayed on the panel based on the size of the resistance (i.e., high and low temperature).

When power is turned on, the panel display temperature higher than the set temperature, the first stage compressor is started first, the first-stage refrigeration system to work, so that the second stage of the refrigeration system condenser temperature drop, the second stage refrigerant temperature drop, the delay of a few minutes, the second-stage refrigeration system to work, it is the inside surfaces of the evaporator, which enables the temperature inside the refrigerator down a lot, it is all the heat emitted from the condenser first stage absorption refrigeration system evaporator, condenser heat released the first stage is scattered in the air when the temperature reaches the set temperature inside the refrigerator, the temperature probe resistance spread the information, control relay de-energized, two refrigeration systems are all stops when the refrigerator temperature rises again, exceeds the set temperature, the refrigerator again to repeat the operation of the process, so that the refrigerator temperature is always maintained among the set temperature.