Specific method of vacuumizing cold storage

There are two methods for vacuumizing small-scale refrigeration system, vacuum pump vacuumizing and compressor vacuumizing.

1. The operation method of vacuum pump is basically the same as that of refrigerator. The difference is that vacuumizing is carried out from the bypass hole channel of the suction stop valve. When vacuumizing, all valves of the system should be opened (if the system has a solenoid valve, it should be powered on separately). When the required vacuum is pumped, the suction cut-off valve and vacuum pump should be closed. Because it takes a long time to vacuumize with a vacuum pump, it is generally not used for open compressors.

2. The operation method of the compressor itself is as follows:

1) cut off the compressor process pipeline, connect the three-way repair valve and close the valve.

2) Cut off the process pipeline of the drying filter (if there is no such process pipeline, add a welding capillary at the outlet).

3) Turn on the compressor, and the air in the system will be discharged from the filtration process pipeline. Start the machine for a while. When no gas is exhausted, block the filter process nozzle by hand and turn off the compressor.

4) Add refrigerant to the system from the maintenance valve. When the pressure indicator is 0. 65438±0 MPa, loosen the filter process nozzle. When the refrigerant is discharged from the nozzle, quickly seal the filter process nozzle with sealing pliers.

5) Start the machine 10 minute, and open the filter process nozzle. At this time, the refrigerant gas is discharged from the nozzle.

6) When the compressor continues to run until there is no air interruption discharge, seal the filter process nozzle, turn off the compressor, and end the self-vacuumizing.

This method is simple, fast and effective, and is often used for the maintenance of open refrigeration systems. If the residual absolute pressure in the system is less than 133Pa or the vacuum degree rises after vacuumizing, the reason must be found out. During the inspection, the method of vacuum pumping by stages can be adopted, that is, it is divided into compressor, low pressure part and high pressure part for vacuum pumping.