1. Leak detection of ultra-low temperature chiller system
1. The refrigerant side of the unit has undergone strict leak detection procedures in the factory and during the commissioning process.
2. After the unit is running, the high pressure part should be checked by a leak detector to ensure the tightness of all connections.
3. If any leaks are found, they should be dealt with immediately. In general, the leakage point can be eliminated by tightening the connecting nut or the flange bolt, but there is also a possibility that the refrigerant must be recovered and then the leakage point should be treated. For example, leaks at welded seams.
Second, the system pressure leak detection
The standard pressure leak detection steps of ultra-low temperature chiller are as follows:
1. Fill a small amount of R-22 gas to a system pressure of 2PSIG.
2. Fill the system with nitrogen to 25-50 PSIG. Make sure that the pressure reaches all parts of the system. You can slightly open the oil filling valve and check for refrigerant with a leak detector.
3. Check every joint and weld, try to be careful and spend as much time as possible. Leak detection equipment used must be sensitive and reliable.
4. Open the top vent valve of the evaporator and condenser and confirm that no refrigerant is detected. If refrigerant is found, remove the end cap to eliminate internal leakage.
5. Confirm that the system is completely sealed, and the gas is discharged from the system at an appropriate flow rate from the filling valve to play a certain purging function.
Vacuum and drying of ultra-low temperature chiller system
1. Connect high-efficiency vacuum pump and mercury vacuum gauge in series to the filling valve of the system.
2. Open all the valves connected to the system, the air extraction valve and the vacuum gauge. Verify that all air vent valves are closed.
3. Start the vacuum pump and draw the vacuum degree of the system to 5mmHg.
4. If conditions permit, 50 o C hot water can be passed into the system to accelerate the evaporation of the system's memory liquid and improve the dryness.
5. Close the shut-off valve and keep the mercury vacuum gauge.
6. Keep the vacuum for 8 hours. If the vacuum rises to not more than 6.3mmHg, the vacuum test is considered qualified.
7. If the vacuum rises above the standard, the leak detection work must be repeated.