How to replace the refrigeration oil in the compressor?

1. the role of refrigeration oil

(1) Lubrication

It can lubricate the surfaces of moving parts of the compressor, reduce resistance and friction, reduce power consumption and prolong service life.

(2) cooling effect

It can take away the heat generated by the friction of the moving surface in time to prevent the compressor from being overheated or burnt out.

(3) Sealing effect

The lubricating oil penetrates into the sealing surface of each friction part to form an oil seal, which plays a role in preventing refrigerant leakage.

(4) Reduce compressor noise

The lubricating oil continuously washes the friction surface and takes away the wear debris, which can reduce the wear of the friction parts.

2. Conditions for replacing refrigeration oil

(1) The refrigeration unit works for a long time, the compressor runs for 2,000 hours to the initial maintenance period, and then runs for 10,000 to 12,000 hours in total before changing the oil;

(2) If the motor burns out, the compressor needs to be replaced, and the oil needs to be changed for 100 hours of continuous operation after replacement;

(3) The refrigeration oil should be replaced after 100 hours of operation of the refrigeration unit used for the cold storage;

(4) Change the oil according to the cleanliness of the refrigeration oil in the refrigeration system.

3. Operation Specifications for Replacing Refrigerant Oil

(1) Close the high-pressure exhaust and low-pressure suction shut-off valves, and use the process valve needle on the compressor to release the refrigerant inside the compressor, so that the compressor crankcase is connected to the atmosphere;

(2) Unscrew the oil drain plug at the bottom of the crankcase, drain the refrigerated oil in the crankcase and remove the filter for cleaning;

(3) Nitrogen can be blown in from the low pressure inflation valve needle, and the oil drain port can be blocked by hand to increase the pressure in the body, further remove the residual oil in the body, blow the cleaned filter into the body and tighten the oil drain plug .

4. Refrigerant oil injection method

(1) Unscrew the process port plunger on the side of the compressor crankcase, and use it as a filling port to pour the refrigeration oil into the crankcase through a suitable tool;

(2) (For piston machine) Connect the low-pressure tube of the fluorine-filled meter to the low-pressure process valve needle of the press cavity, use a vacuum pump to pump the crankcase to negative pressure, remove the other fluorine-filled tube separately, and insert one end into the In the container with refrigeration oil, the other end is connected to the valve needle of the low-pressure suction end of the oil pump, and the refrigeration oil is sucked into the crankcase by the negative pressure in the crankcase;

(3) Since there may be a certain amount of residual oil in the original system, it can be added less when changing the oil, generally adding it to a position slightly higher than the lower limit of the oil sight glass marking line;

(4) After the refrigeration oil filling is completed, tighten the process plunger or remove the fluorine filling pipe, and connect the fluorine pressure gauge to vacuum the compressor;

(5) After vacuuming, open the high and low pressure shut-off valve of the compressor to check whether there is refrigerant leakage;

(6) If there is no leakage point, wait for 20 minutes to start the unit;

(7) Check the lubrication condition of the compressor and the oil level of the sight glass immediately after turning on the unit. If the oil level is lower than the normal range (1/4 sight glass), the refrigeration oil must be supplemented. If necessary, connect an oil pressure gauge to the needle valve of the oil pump to check the oil pressure. The pressure on the suction side of the oil pump should be basically the same as the low-pressure suction pressure. The allowable value of the oil pressure difference is 1.4 ~ 3.5bar. The screw machine is a differential pressure type oil return. , without oil pump.

5. refueling matters needing attention

(1) Refrigerated oil has a certain degree of hygroscopicity. The water in the oil reacts chemically with the oil, and cannot be removed by vacuuming. Special care is required during work to minimize the air entering the system and the oil storage container;

(2) When replacing the compressor, it should be noted that there is a certain amount of refrigeration oil in the original refrigeration system, and the oil in the system should be blown out if necessary. risk of liquid hammer;

(3) It is recommended not to replace the refrigeration oil in rainy days.