How to solve the oil leakage fault of the industrial chiller?
At present, many industrial chillers on the market are constructed according to the following idea: mixing refrigerating oil and refrigerant, using an oil separator to separate the refrigerated oil from the refrigerant, and then returning the refrigerant to the compressor through a flooded evaporator. This type of model has good cooling effect and a large degree of promotion, but there is a problem in its operation, that is, it is easy to "run off", that is, when the cooling water temperature is low, the exhaust gas superheat is not high, and the oil is separated from the refrigerant. Incomplete, after the mixture enters the heat exchanger, the low pressure of the unit will be low, and even worse, the expansion valve will be blocked and the industrial chiller unit cannot be started.
The symptoms are as follows:
1. No trace of oil can be seen in the oil separator. At this moment, the oil does not collect in the condenser, but enters the evaporator through the expansion valve. The oil will stick to the heat exchange copper tube of the evaporator, causing it to evaporate. The evaporation effect of the compressor is not good, resulting in a low pressure in the evaporator, and at the same time, the suction superheat of the compressor is very low, and the refrigerant liquid is directly sucked in. When the compressor discharge temperature is very low, the oil and the refrigerant still cannot be separated. , Such a vicious cycle will cause all the oil to collect in the evaporator, the compressor will make a huge noise due to insufficient oil supply, and even the oil level of the oil separator of the industrial chiller unit will be shut down.
2. No trace of oil can be seen in the oil separator. All the oil comes to the condenser with the exhaust gas. If the water temperature continues to be low, all the oil will collect in the condenser and cause the expansion valve to occur. The oil is blocked, and the pressure in the evaporator starts to decrease due to insufficient liquid supply, until the low pressure alarm and shutdown.
The above is the so-called runaway phenomenon. The main reason is that the chilled water temperature is low and the exhaust temperature is low.