What are the reasons for overheating of the compressor of the -135°C water vapor cryogenic freezer

What are the causes of overheating of the cold compressor of the -135°C water vapor cryogenic refrigeration mechanism? In fact, there are the following reasons: high return air temperature, large motor heating, high compression ratio, high condensing pressure, and improper
selection of refrigerant.
So, let the editor explain it
to you.
1.
High return gas temperature: The return gas temperature is relative to the
evaporation temperature.
In order to prevent liquid return, the general return gas pipeline requires a return air superheat of
20 degrees.
If the return line is not well insulated, the superheat is far more than 20 degrees
.
2.
Motor heating: For return air cooled compressors, the refrigerant vapor is heated by the motor when it flows through the motor cavity, and the suction temperature of the cylinder is increased
again.
The heat generation of the motor is affected by power and efficiency, and the power consumption is closely related to
displacement, volumetric efficiency, working conditions, friction resistance, etc.
3.
The compression ratio is too high: the exhaust temperature is greatly affected by the compression ratio, and the larger the compression ratio, the higher
the exhaust temperature.
Reducing the compression ratio can significantly reduce the exhaust temperature, including by increasing the suction pressure and lowering the exhaust pressure
.
The suction pressure is determined
by the evaporation pressure and the suction line resistance.
Increasing the evaporation temperature can effectively increase the suction pressure, quickly reduce the compression ratio, and thus reduce the exhaust temperature
.
Reducing the resistance of the return air line can also increase the return air pressure, including replacing the dirty return air filter in time, and reducing the length of the evaporation pipe and return air line as much as possible
.
In addition, insufficient refrigerant is also a factor in
low suction pressure.
Refrigerant should be replenished
in time after leakage.
4.
The main reason for excessive exhaust pressure is that the condensing pressure is too high
.
Insufficient heat dissipation area of the condenser, fouling, insufficient cooling air volume or water volume, too high cooling water or air temperature, etc.
can lead to excessive
condensing pressure.
It is important to
select the appropriate condensing area and maintain adequate cooling medium flow.
5.
The thermophysical properties of different refrigerants are different, and the exhaust temperature rises differently
after undergoing the same compression process.
Therefore, for different refrigeration temperatures, different refrigerants
should be selected.
The normal operation of the -135°C water vapor cryofreezer should not have overheating phenomena
such as high motor temperature and exhaust steam temperature that are too high within the scope of use.
Compressor overheating is an important failure signal, indicating a serious problem with the refrigeration system or improper
use and maintenance of the compressor.