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    Home > Active Ingredient News > Drugs Articles > Causes of compressor exhaust overheat

    Causes of compressor exhaust overheat

    • Last Update: 2018-10-14
    • Source: Internet
    • Author: User
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    The main reasons for the overheating of exhaust gas temperature are as follows: high return gas temperature, large heating capacity of motor, high compression ratio, high condensation pressure and improper selection of refrigerant 1 The high temperature of return gas is relative to the evaporation temperature In order to prevent liquid return, the general return pipeline requires a return superheat of 20 ° C If the heat preservation of the return pipeline is not good, the superheat will be far more than 20 ° C The higher the return air temperature, the higher the suction and exhaust air temperature of the cylinder When the return gas temperature increases by 1 ° C, the exhaust gas temperature will increase by 1 ~ 1.3 ° C 2 Motor heating for the return air cooling compressor, the refrigerant vapor is heated by the motor when it flows through the motor cavity, and the suction temperature of the cylinder is increased again The heat output of motor is affected by power and efficiency, while the power consumption is closely related to displacement, volumetric efficiency, working condition, friction resistance, etc The temperature rise range of the refrigerant in the motor cavity of the return air cooled half sealed compressor is about 15 ~ 45 ° C In air-cooled (air-cooled) compressors, the cooling system does not go through the winding, so there is no heating problem of the motor 3 The higher compression ratio, the higher exhaust temperature Reducing the compression ratio can significantly reduce the exhaust temperature, including increasing the suction pressure and reducing the exhaust pressure Suction pressure is determined by evaporation pressure and suction line resistance Increasing the evaporation temperature can effectively increase the suction pressure, rapidly reduce the compression ratio, and thus reduce the exhaust temperature Some users unilaterally think that the lower the evaporation temperature, the faster the cooling rate, which actually has many problems Although reducing the evaporation temperature can increase the refrigeration temperature difference, the refrigeration capacity of the compressor decreases, so the refrigeration speed is not necessarily fast Moreover, the lower the evaporation temperature is, the lower the refrigeration coefficient is, while the load is increased, the longer the operation time is, the greater the power consumption will be Reducing the resistance of the return line can also improve the return pressure The specific methods include replacing the dirty filter in time, reducing the length of the evaporation pipe and the return line as much as possible In addition, insufficient refrigerant is also a factor of low suction pressure The refrigerant shall be replenished in time after leakage Practice shows that it is more simple and effective than other methods to reduce exhaust temperature by increasing suction pressure The main reason for the high exhaust pressure is the high condensation pressure Insufficient cooling area of condenser, crud, insufficient cooling air volume or water volume, too high temperature of cooling water or air can cause too high condensation pressure It is very important to choose suitable condensation area and maintain sufficient cooling medium flow High temperature and air conditioning compressor design of the operation compression ratio is low, used for refrigeration after the compression ratio multiplied, exhaust temperature is very high, and cooling can not keep up, resulting in overheating Because of this, avoid using the compressor beyond the scope, and make the compressor work under the possible small pressure ratio In some low temperature systems, overheating is the primary cause of compressor failure 4 After the start of the reverse expansion and gas mixing suction stroke, the high-pressure gas trapped in the cylinder clearance will have a reverse expansion process After the counter expansion, the gas pressure returns to the suction pressure, and the energy consumed to compress this part of gas is lost in the counter expansion On the one hand, the smaller the clearance is, the smaller the power consumption caused by the reverse expansion is On the other hand, the larger the suction capacity is, the greater the energy efficiency ratio of the compressor is In the process of reverse expansion, the gas contacts with the high temperature surface of valve plate, piston top and cylinder top to absorb heat, so the gas temperature will not reduce to the suction temperature at the end of reverse expansion After the counter expansion, the positive inspiratory process begins When the gas enters the cylinder, on the one hand, it is mixed with the anti expansion gas, and the temperature rises; on the other hand, the mixed gas absorbs heat from the wall and heats up Therefore, the gas temperature at the beginning of the compression process is higher than the suction temperature However, the actual temperature rise is very limited, generally less than 5 ° C due to the very short process of reverse expansion and suction The anti expansion is caused by the clearance of the cylinder, which is an unavoidable disadvantage of the traditional piston compressor If the gas in the vent hole of valve plate cannot be discharged, there will be reverse expansion 5 The thermophysical properties of different refrigerants are different, and the exhaust temperature rise is different after the same compression process Therefore, different refrigerants should be selected for different refrigeration temperatures Conclusion and suggestion: there should be no overheating phenomenon such as motor high temperature and exhaust steam temperature during normal operation of compressor Compressor overheating is an important fault signal, which indicates that there are serious problems in the refrigeration system, or the compressor is not properly used and maintained If the cause of compressor overheating lies in the refrigeration system, the problem can only be solved by improving the design and maintenance of the refrigeration system Replacing a new compressor will not eliminate the problem of overheating fundamentally.
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