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Main Cause Of Overheating Of Exhaust Temperature In High And Low Temperature Test Chamber
Oct 20, 2017

High and low temperature test chamber refrigeration compressor in the use of normal operation should not have the motor temperature and exhaust temperature is too high overheating phenomenon. Compressor overheating is an important fault signal, indicating that the refrigeration system there are more serious problems, or improper use and maintenance of the compressor.

High and low temperature test chamber compressor exhaust temperature overheating reasons are the following: high return air temperature, the motor heating capacity, high compression ratio, high condensing pressure, improper refrigerant selection.

(1) Compressor return air temperature is high

The return air temperature is relative to the evaporation temperature. In order to prevent backflow, the general return air line requires 20 ° C return air superheat. If the return air pipe insulation is not good, superheat is far more than 20 ° C.

(2) motor heating

For the return air cooled compressor, the refrigerant vapor is heated by the motor as it flows through the motor chamber, and the cylinder suction temperature is raised again. Motor heat is affected by power and efficiency, and power consumption and displacement, volumetric efficiency, working conditions, frictional resistance are closely related.

(3) compression ratio is too high

The exhaust temperature is greatly affected by the compression ratio, the greater the compression ratio, the higher the exhaust temperature. Reducing the compression ratio can significantly reduce the exhaust temperature, including by increasing the suction pressure and reducing the exhaust pressure.

High and low temperature test chamber Exhaust pressure is too high the main reason is the condensation pressure is too high. Condenser cooling area is insufficient, fouling, cooling air volume or water shortage, cooling water or air temperature is too high can lead to excessive condensation pressure. It is important to choose the appropriate condensate area to maintain adequate cooling medium flow. The compressor should be used in a super-range and the compressor should be operated at the lowest possible pressure ratio. In some low-temperature systems, overheating is the primary cause of high and low temperature test chamber compressor failure.

(4) anti-expansion and gas mixture

After the start of the suction stroke, the high pressure gas retained in the clearance of the cylinder will have an anti-expansion process. After the expansion of the gas pressure back to the suction pressure, used to compress this part of the gas and the energy consumed in the anti-expansion on the loss. The smaller the clearance, on the one hand, the smaller the power consumption caused by the anti-expansion, the greater the amount of suction on the other hand, the compressor energy efficiency is greatly increased.

(5) Compression temperature rise and refrigerant type

The different physical properties of the refrigerant are different, and the same amount of exhaust gas temperature is different during the same compression process. Therefore, for different cooling temperatures, different refrigerants should be used.