A, the role of lubricating oil:
1) in the screw and compression chamber and between the yin and yang screw to form a dynamic seal, reduce the refrigerant in the compression process from the high pressure side to the low pressure side of the leakage.
2) cooling the refrigerant being compressed, oil is sprayed into the compressor, absorbing the heat generated by the refrigerant gas in the compression process, reducing the exhaust temperature.
3) In the bearing and screw between the formation of oil film to support the rotor, and play a role in lubrication.
4) Transfer the differential pressure force, drive the capacity adjustment system, by the action of the compressor’s unloading and adding solenoid valve, adjusting the position of the capacity adjustment slider, to achieve the compressor capacity adjustment control.
5) Reduce operating noise
Description:
Compressor internal lubricant is the key to maintain the normal operation of the compressor, the general lubricant problems are:
1) foreign matter mixed in, resulting in lubricating oil pollution, blocking the oil filter.
2)High temperature effect causes the lubricant to deteriorate and lose the lubrication function.
3) System water pollution, acidification, erosion of the motor.
Second, the compressor refrigeration oil testing and replacement:
For the system manufacturer, the compressor refrigeration oil testing and replacement cycle is related to the process control of its production process. If the system’s evaporator and condenser and system piping cleanliness control is relatively good, then relatively less contaminants into the compressor, the detection and maintenance cycle can be relatively longer.
Main monitoring indicators:
1) PH value index: the acidification of the lubricating oil will directly affect the life of the compressor motor, so the acidity of the lubricating oil should be checked regularly to see if it is qualified. General lubricant acidity below PH6 is required to replace. If the acidity cannot be checked, the filter drier of the system should be replaced regularly to keep the system dryness in normal condition.
2) Pollution index: If the pollutants in 100ml of refrigeration oil exceed 5mg, it is recommended to replace the refrigeration oil.
3)Water content: If it exceeds 100ppm, it is necessary to replace the refrigeration oil.
Replacement cycle:
Generally every 10,000 hours of operation shall check or replace the lubricant, and after the first operation, 2500 hours is recommended to replace the lubricant and clean the oil filter. Because the residue of system assembly will be accumulated in the compressor after the official operation. Therefore, the lubricating oil should be changed once in 2500 hours (or 3 months), and then regularly according to the system cleanliness, if the system cleanliness is good, it can be changed once every 10000 hours (or annually).
Compressor discharge temperature if long-term maintenance in the high temperature state, then the lubricant deterioration progress quickly, must be regularly (every 2 months) check the chemical characteristics of the lubricant, failed to be replaced. If you can’t check regularly, you can follow the following suggestion table.
Three, refrigeration oil replacement operation method:
1) Refrigeration oil replacement without internal cleaning:
The compressor does pumping action to recover the system refrigerant to the condenser side (note that the minimum suction pressure of pumping action is not less than 0.5Kg/cm2G), remove the refrigerant from the compressor, retain some internal pressure as the power source, and discharge the refrigerant oil from the oil discharge angle valve of the compressor.
2) Change the refrigerant oil and clean the inside:
Drain the oil action as described above, after the refrigerant oil is removed and the pressure inside and outside the compressor is balanced, use the hexagonal wrench to loosen the flange bolts, remove the oil filter connector and clear the hole flange (or oil level switch flange), remove the pollutants in the compressor oil tank, and check whether the oil filter hole mesh is broken, and blow out the sludge and pollutants on it, or replace the oil filter with a new one, note that When replacing the new filter interface nut should be screwed tightly and sealed well to prevent internal leakage; the liner inside the oil filter joint must be replaced with a new one to prevent internal leakage; other flange liner is also recommended to be updated.
IV. Notes:
1. Different brands of refrigeration oil must not be mixed, especially mineral oil and synthetic ester oil must not be mixed.
2. If replacing different grades of refrigeration oil, pay attention to the original refrigeration oil remaining in the system to be excluded.
3. Some oils are hygroscopic, so do not expose the oil to the air for a long time. Shorten the exposure time as much as possible and evacuate as much as possible during installation.
4. If the system has a compressor motor burn failure, pay special attention to remove the residual acid from the system when replacing the new machine, and check the acidity of the refrigeration oil after seventy-two hours of commissioning operation, it is recommended to replace the refrigeration oil and filter drier to reduce the possibility of acid corrosion. Thereafter, test or replace the refrigerant oil again after about one month of operation.
5. If the system has had an accident of water ingress, pay special attention to remove the water cleanly, and in addition to replacing the refrigeration oil, pay special attention to detect the acidity of the oil and replace the new oil and filter drier in time.
Post time: May-29-2023
