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Which three points should refrigerating machine manufacturers pay attention to when doing air tightness test
After the assembly of each refrigeration unit is completed, a series of tests are required to ensure the safe and stable operation of the unit, and there is an air tightness test. So, what should the refrigerator manufacturer pay attention to when doing the air tightness test?
The air tightness test is to add nitrogen with sufficient pressure into the refrigerant piping to check whether there is leakage in the refrigeration system of the refrigeration unit. In the inspection process, there are 3 points to note:
1, refrigerant, oxygen, flammable and toxic gases cannot be used as pressurized gas;
2, it must be pressurized at both ends of the liquid pipe and air pipe of the refrigeration unit;
3. Use a pressure gauge with an effective pressure scale greater than the design pressure;
After the above three precautions are confirmed, we will start the specific operation of the air tightness test. During the pressurization process, the pressurization should not suddenly reach the specified pressure range, and the pressurization should be performed slowly.
1. When the pressure reaches 0.5MPa, stop for 5 minutes to confirm whether the pressure drops;
2, when the pressure reaches 1.5MPa, stop for another 5 minutes to confirm whether there is a pressure drop;
3. When the pressure reaches the specified pressure (that is, the design pressure of the refrigeration unit), the surrounding temperature and pressure should be recorded;
4. After being pressurized for one day, the pressure does not drop after one day, it means it is qualified; if the pressure drops in the above three steps, it means that there is a leak in the refrigeration unit, which needs to be leaked and repaired.
Note: The pressure after one day of storage will change according to temperature changes. If the temperature changes by 1°C, the pressure will change by about 0.01 MPa. This should be corrected when checking the pressure one day later.
The refrigeration unit is a commonly used refrigeration equipment in various industries. Before the unit leaves the factory, the manufacturer will do an airtight test, a vacuum test, and fill an appropriate amount of refrigerant to confirm the normal operation of the unit and ensure that the user receives the refrigeration. After the machine, it can be put into use after connecting the power supply, pipes, water system, etc. as required.
