The cause of frost on the surface of the temperature and humidity test chamber on the table

Tabletop constant temperature and humidity test box is to maintain high and low temperature test and cold and humid natural environment of the experimental equipment, in the usual inspection of the whole process of experimental application, many customers have encountered the problem of frosting on the surface of the machine and equipment, then what elements cause the surface of the table constant temperature and humidity test box frost? About the table constant temperature and humidity test box surface frost problems, the quality of machinery and equipment is not only, the key point is still the problem of maintenance and maintenance, maintenance for the service life of the high temperature test chamber plays a fundamental role, the cause of the following: machine and equipment processing process pipe long-term idle: the processing process pipe of the table constant temperature and humidity test chamber after opening, no sealing or not immediately repaired, so that the long-term idle frost and then often start, the moisture in the gas is brought to the fuselage from outside the branch pipe, and then frost occurs
。
Refrigeration compressor is not sealed: if the machine and equipment are terminated for a long time, there is no need to maintain the solution, and if the refrigeration compressor is not sealed for a long time, if it is not solved by dry and irritable, it will be transferred to the frost application, which will also lead to freezing
.

Damage to the refrigerated air conditioner evaporator: After the damage of the refrigerated air conditioner evaporator, the oxygen molecules in the cold room are brought to the refrigeration compressor together with the water vapor in the gas for a long time (the air pressure caused by the air conditioning evaporator at startup, and the atmospheric pressure bubble will bring the oxygen molecules in the wet and cold gas to the fuselage), which will also lead to freezing
.

Air conditioning evaporator natural ventilation is not good: if the air conditioning evaporator of the constant temperature and humidity test box on the table is not well ventilated, the refrigeration capacity will not move will also cause the air conditioning evaporator to frost or freeze, which may lead to the bottom pressure working pressure is too low, which will lead to the frost condition
of the refrigeration compressor casing.

Too much refrigerant: the table constant temperature and humidity test box in all normal working conditions, the refrigeration compressor suction back is the refrigerant steam and not the liquid, if the refrigeration unit in the refrigerant is too much and the refrigeration oil charge is too much or the air conditioning expansion valve adjusts the total flow is too large, so that the refrigerant in the air conditioning evaporator is not completely volatilized, resulting in the refrigerant with wet steam or liquid is sucked back by the refrigeration compressor, resulting in freezing
.

Left and right is caused by the frost on the surface of the table constant temperature and humidity test chamber, a large number of reasons for the lack of proper practical operation and maintenance caused, if you pay more attention to the application of the whole process can prevent the occurrence of this problem, perhaps this and the quality of the machine and equipment must also be related
.