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    So far, it has been confirmed that the cause of the production failure is the leakage of refrigerant R23 in the low temperature (R23) stage unit of the main unit. The refrigeration system was checked for leaks, and a leak detector was used in combination with soapy water. Replace the solenoid valve, recharge the system with fluorine, and the system runs normally. Because it can be seen from the above, the analysis and determination of the fault phenomenon of the ultrasonic cleaning machine is basically easy to difficult, first "outside" and then "inside", first "electric" and then "refrigeration" Analysis and judgment, understanding and understanding of the principle and working process of the test box is the basis for analyzing faults and judging faults. Under normal circumstances, the constant temperature and humidity test box will be cooled to the corresponding value according to the set time range, but because the equipment has been used for too long or improperly operated, it will cause the constant temperature and humidity test box to cool down slowly. To solve this problem, conduct a technical discussion.

    Reason 1:

1. One is the main unit and the other is the auxiliary unit. When the cooling rate is large, the two groups of units work at the same time. In the early stage of temperature maintenance, the two groups of units still work at the same time. When the temperature is initially stable, the auxiliary unit stops working, and the main unit keeps the temperature stable. If the R23 of the main unit leaks, the cooling effect of the main unit will be small, because during the cooling process, the two units work at the same time, so there is no phenomenon that the temperature is not chaotic, and the indicated cooling rate decreases. In the temperature maintenance stage, once the auxiliary unit stops working and the main unit has no cooling effect, the air in the test box will slowly rise. When the temperature rises to a certain level, the control system will start the auxiliary unit to cool down and reduce the temperature to the set Fixed value (-55 ℃) around, and then the auxiliary unit stops working again, if this is repeated, the failure phenomenon shown in Figure 3 will appear.

2. The cause of the failure is not determined, and the cause of the failure is further confirmed in combination with the control process of the test chamber. The test chamber of the ultrasonic cleaner has two sets of refrigeration units.

    Reason 1:

3. Because the temperature cannot be maintained, observe whether the refrigeration compressor can be started during the operation of the test chamber, and the compressor can be started during the operation of the environmental test equipment, indicating that the electrical circuit from the main power supply to each compressor is normal, and the electrical There are no problems with the system.

4. Touch the exhaust and suction pipelines of the R23 compressor of the main engine group by hand. The medical ultrasonic cleaner found that the temperature of the exhaust pipeline is not high, and the temperature of the suction pipeline is not low (not frosted), which is also Explains the lack of R23 refrigerant in the main engine group.

5. There is no problem with the electrical system, continue to check the refrigeration system. First, check that the exhaust and suction pressures of the low-temperature (R23) stage compressors of the two sets of refrigeration units are lower than the normal values, and the suction pressure is in an evacuated state, indicating that the amount of refrigerant in the main refrigeration unit is insufficient.