How to avoid as far as possible refrigeration compressor caused by lack of oil failure

Refrigeration compressor lack of oil, that is, insufficient lubricating oil in the compressor. Usually we will judge whether there is a lack of oil through the oil mirror on the compressor body. Once there is a lack of oil in the compressor, the amount of oil in the crankcase is little or even no oil. When discharging refrigerant gas, refrigeration compressor will also take away a part of lubricating oil, which is usually called running oil or running oil. This is inevitable. There is about 2-3% lubricating oil in the exhaust of half sealed piston compressors and 0.5-1% in scroll compressors. If the lubricating oil from the compressor does not come back, the compressor will be short of oil. Reduce the amount of oil in refrigeration compressor, usually installed in the system oil separator or return pipe, generally can separate 50-95% of the oil, oil return effect is good. However, there are also difficult cases of oil return.

The pipeline is particularly long cold storage refrigeration system, full liquid ice system and very low temperature freeze-drying equipment, refrigeration compressor boot after more than ten minutes or even tens of minutes of no oil return or oil return is very small situation is not rare, which requires the installation of efficient oil separator.

The lower the evaporation temperature, the more difficult it is to return the oil. The solution is that the design of the evaporation pipeline and the design and construction of the return pipe must be conducive to the return of oil. The common practice is to use the design of the down type pipeline and ensure the greater airflow speed. In addition to high efficiency oil separators, special solvents are often added to prevent oil from plugging capillary and expansion valves and to assist in oil return.

When the refrigeration compressor is positioned higher than the evaporator, an oil return bend on the vertical return pipe is necessary. The return bend should be as compact as possible to reduce oil storage. The spacing between the oil return bends should be appropriate. The number of oil return bends is more, and some lubricating oil should be added.

If the refrigerant leaks too much, the air return speed will decrease. If the speed is too low, the lubricating oil will stay in the air return pipe and cannot quickly return to the refrigeration compressor.