Common faults of refrigeration compressors

1. Inhalation temperature too high

The high suction temperature is mainly caused by an increase in suction superheat. Note that a high suction temperature does not necessarily mean a high suction pressure, as the suction is superheated steam. Under normal circumstances, the compressor cylinder head should be half cool and half hot. If the intake temperature is too high, the cylinder head will all heat up. If the intake temperature is higher than the normal value, the exhaust temperature will also increase accordingly.

2. Low suction temperature

Low suction temperature - mainly caused by a large liquid supply to the evaporator, resulting in low suction superheat.

3. Abnormal exhaust temperature

Abnormal exhaust temperature - influencing factors: adiabatic index, compression ratio, intake temperature.

The exhaust temperature of the compressor can be read from the thermometer on the exhaust pipeline. It is related to the adiabatic index, compression ratio (condensation pressure/evaporation pressure), and suction temperature of the refrigerant. The higher the intake temperature and compression ratio, the higher the exhaust temperature, and vice versa.

4. High exhaust pressure

The exhaust pressure generally corresponds to the high or low condensing temperature. Under normal circumstances, the discharge pressure of the compressor is very close to the condensation pressure. High exhaust pressure will increase compression power, reduce gas transmission coefficient, and thus decrease refrigeration efficiency.

5. Exhaust pressure too low

Low exhaust pressure - mainly caused by a small or even stopped refrigerant flow in the refrigeration system pipeline.

6. Insufficient displacement

Insufficient displacement - mainly compared to the design air volume of the compressor, it is one of the most common faults of the compressor, which is mainly caused by the following reasons:

（1）The intake filter is clogged with dirt or the compressor suction pipe is too long or too small, which increases the suction resistance and affects the suction volume, resulting in a decrease in the exhaust volume.

（2）The decrease in compressor speed leads to a decrease in displacement. If the compressor is used in an improper environment, the displacement of the compressor is designed based on a certain altitude (mainly the air compressor), suction temperature, humidity, and power supply. When it is used in an environment that exceeds the above standards, such as when the air compressor is used in a high-altitude environment, it will cause a decrease in suction pressure, and the displacement will also be affected.

（3）Poor sealing of the packing leads to air leakage and a decrease in exhaust volume. The first reason is that the filler itself was manufactured without meeting the requirements; Secondly, air leakage may be caused by wear and tear during installation; Generally, lubricating oil is added to the packing to provide lubrication, sealing, and cooling.

Shanghai KUB Refrigeration Equipment Co., Ltd.

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