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Location:Home > news > Industry dynamic - Key points of oil replacement in screw refrigeration compressor

Key points of oil replacement in screw refrigeration compressor
Release time:2018-6-8 11:23:23      Number of clicks:359
I. functions of lubricating oil:
1) dynamic seal is formed between the screw and the compression chamber and the yin-yang screw to reduce the leakage of refrigerant from the high-pressure side to the low-pressure side in the compression process.
2) cool the compressed refrigerant. Oil is sprayed into the compressor to absorb the heat generated by the refrigerant gas during the compression process and reduce the exhaust temperature.
3) oil film is formed between the bearing and the screw to support the rotor and play a lubricating role.
4) transfer the pressure differential force, drive the capacity adjustment system, adjust the position of the tolerance adjustment slider through the action of adding and unloading the electromagnetic valve of the compressor, and realize the capacity adjustment control of the compressor.
5) reduce operating noise
The inner lubricating oil of compressor is the key to maintain the normal operation of compressor. The problems of general lubricating oil include:
1) foreign matter mixed in, causing lubricating oil pollution and blocking oil filter.
2) high temperature effect leads to deterioration of lubricating oil and loss of lubrication function.
3) water pollution, acidification and erosion of the system motor.
Ii. Testing and replacement of compressor frozen oil:
For the system manufacturer, the testing and replacement cycle of the refrigeration oil is related to the process control of the production process. If the system of the evaporator and condenser and the cleanliness of the piping control is better, then into the compressor of the pollutants is relatively less, detection and maintenance cycle can be relatively longer.
Main monitoring indicators:
1)PH value index: the acidification of lubricating oil will directly affect the service life of compressor motor, so the acidity of lubricating oil should be checked regularly. General lubricants below PH6 must be replaced. If the acidity cannot be checked, the drying filter of the system should be changed regularly to keep the system in a normal state.
2) pollution index: if the pollutant in 100ml frozen oil exceeds 5mg, it is recommended to replace frozen oil.
3) water content: over 100ppm, it needs to be replaced with frozen oil.
Replacement cycle:
Generally, the lubricating oil should be checked or replaced once every 10,000 hours. After the first operation, it is recommended to replace the lubricating oil once and clean the oil filter after 2500 hours. Because the system assembly residue will accumulate in the compressor after the official operation. Therefore, the lubricating oil should be replaced once every 2500 hours (or 3 months). After that, it should be replaced regularly according to the state of system cleanliness. If the system cleanliness is good, it can be replaced every 10,000 hours (or every year).
If the exhaust temperature of the compressor is maintained at high temperature for a long time, the deterioration of the lubricating oil will be rapid, and the chemical properties of the lubricating oil shall be inspected regularly (every 2 months). If periodic inspection is not possible, it can be performed according to the following recommendation table.
Iii. Operation method of freezing oil replacement:
1) replace frozen oil without internal cleaning:
Pump sets, compressor do system refrigerant reclaiming to condenser side action (note the pump set minimum suction pressure not less than 0.5 Kg/cm2G), will be refrigerant compressor, retain some internal pressure as power source, the frozen oil from the Angle of the compressor oil drain valve.
2) replace frozen oil and conduct internal cleaning:
Dumping actions as mentioned above, frozen oil out clean and compressor pressure balance inside and outside, the flange bolts loose with Allen key, oil filter down joints and settle accounts after the orifice flange (flange) or oil level switch, the pollutant removal within the compressor tank clean, and check the oil filter mesh to see if there is any breakage, and the sludge, pollutants, such as blow, or replace a new oil filter, pay attention to change new filter interface nut to tighten, good sealing, prevent leakage; The inner liner of the oil filter joint must be replaced to prevent internal leakage. Other flange gaskets are also recommended for renewal.
Iv. Matters needing attention:
1. Different brands of frozen oil shall not be mixed, especially mineral oil and synthetic ester oil.
2. If different brands of frozen oil are replaced, please be careful to remove the remaining original frozen oil from the system.
3. Some oil products have the characteristics of moisture absorption, so do not expose frozen oil to air for a long time. Install as much as possible to shorten the exposure time, and do a good vacuum operation.
4. If the system had burned compressor motor fault, replace the new machine should pay special attention to remove residual acid system, and seventy-two hours after the debugging is running check frozen oil acidity, recommend replacing the frozen oil, and dry filters, may reduce the acid corrosion. After running for a month or so, retest or replace the frozen oil.
5. If the system accidents have occurred into the water, it is important to pay special attention to remove water clean, in addition to the replacement of frozen oil, paying special attention to the detection of oil acidity, and timely replacement of the new oil and filter drier.
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Next:About the return oil of refrigeration compressor

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