Analysis of Causes and Phenomena of Cross-flow in Refrigeration Compressors

Analysis of Causes and Phenomena of Cross-flow in Refrigeration Compressors

Causes, phenomena and effects of cross-flow:

The main reason for compressor cross-flow is that the valve plate (air valve) inside the compressor is not closed tightly. This may be caused by valve wear, aging, deformation or improper installation. When the valve plate is not closed tightly, part of the exhaust gas will leak into the suction chamber, causing cross-flow.

Cross-flow phenomenon:

Increase in compressor exhaust temperature: Since the high-pressure exhaust gas is connected to the low-pressure suction gas, the suction temperature is heated, making the exhaust temperature after compression higher.

Increase in compressor operating temperature: The high-temperature exhaust gas inside the compressor mixes with the suction gas, causing the overall operating temperature of the compressor to increase. The return air pipe of the compressor is very hot, the operating sound is very small, and the current is small.

Changes in suction and exhaust pressure: The suction pressure increases and the exhaust pressure decreases, because the high-pressure gas leaks into the low-pressure chamber, causing the low-pressure chamber pressure to rise, while the high-pressure chamber pressure decreases.

Changes in power consumption and current: Since the high and low pressure difference between the suction and exhaust gas becomes smaller, the compression ratio decreases, resulting in a decrease in the operating power consumption of the compressor, and the current will also be lower than normal.

Effect of cross-flow:

Decrease in refrigeration effect: Cross-flow of the compressor leads to a decrease in the refrigerant circulation efficiency, thus affecting the refrigeration effect of the system.

Affected system stability: Cross-flow phenomenon will cause the high pressure of the system to be low and the low pressure to be high, which will affect the stability of the system.

Shortened compressor life: Long-term cross-flow will cause the parts inside the compressor to be washed by high temperature and high pressure, thereby accelerating wear and aging, and shortening the service life of the compressor.

Diagnostic method Observe the operating status of the compressor

By observing the operating temperature, pressure, current and other parameters of the compressor, it can be preliminarily determined whether the compressor has cross-flow.

Test the suction and exhaust pressure: Use professional testing tools to test the suction and exhaust pressure of the compressor. If the high and low pressure differential is small, it may indicate the presence of cross-flow.

Check the inside of the compressor: Disassemble the compressor and check the wear, aging, deformation, etc. of the valve plate, and whether the valve plate is installed in place.