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[technology sharing] common faults and troubleshooting of refrigeration compressor

作者:xuemei 点击:107 发布时间:2020-09-16

Compressor is the heart of refrigeration system. It inhales low temperature and low pressure refrigerant gas from the suction pipe, and drives the piston to compress it through motor operation, and then discharges high temperature and high pressure refrigerant liquid to the exhaust pipe, which provides power for the refrigeration cycle, thus realizing the refrigeration cycle of compression condensation expansion evaporation (heat absorption).


Let's now look at the common compressor faults and Troubleshooting:


1、 Sudden shutdown of compressor during operation:


1. the reasons for sudden shutdown of compressor during operation are as follows:


(1) Suction pressure is too low, lower than the low-pressure lower limit of pressure relay;


(2) The exhaust pressure is too high, which causes the high-voltage relay to operate and power off;


(3) The oil pressure is too low, and the oil pressure relay acts as relay;


(4) Motor overload, thermal relay action relay;


2. the elimination method of sudden shutdown of compressor during operation:


(1) Check the cause, if the pipeline is blocked, the pipeline shall be unblocked, and if the system refrigerant is insufficient, it shall be supplemented;


(2) Check the cooling capacity or cooling air volume of condenser;


(3) Check the pipeline and oil pump of oil transportation system;


(4) Check whether the power supply voltage is low or the cold load is too large;


2、 Exhaust compression too high


1. the reasons for excessive exhaust compression are as follows:


(1) The cooling water of water-cooled condenser is insufficient or the cooling air volume of air-cooled condenser is insufficient;


(2) The surface of condenser pipe cluster is too thick or oil pollution is too thick, which makes it difficult to heat;


(3) Air in the refrigeration system;


(4) Too much refrigerant filling;


(5) The valve in the exhaust pipe fails, causing the pressure to be too high;


2. exhaust compression too high removal method:


(1) Check whether the valve is fully open, increase water supply or check whether the motor voltage, speed and drive belt are too loose;


(2) Clean the scale and oil stain to clean the surface of condenser pipe cluster;


(3) Let go of the air;


(4) Discharge excess refrigerant;


(5) Check and correct the valve;


3、 Wet stroke of compressor


1. the causes of wet stroke of compressor are as follows:


(1) The thermal expansion valve fails and the opening is too large;


(2) The solenoid valve fails. After shutdown, a large amount of refrigerant enters the evaporation discharge pipe, and enters the compressor when the valve is started again;


(3) The system is filled with too much refrigerant;


(4) The temperature sensing package of thermal expansion valve is loose and not bound, which results in the increase of opening degree of thermal expansion valve;


2. removal method of wet stroke of compressor:


(1) Close the liquid supply valve and repair the thermal expansion valve;


(2) Maintenance of solenoid valve;


(3) Discharge excess refrigerant;


(4) Check the binding of temperature sensitive package;


4、 Compressor stuck


1. the causes of compressor jamming are as follows:


(1) There are dirt and impurities in the lubricating oil;


(2) The oil delivery pipe of the oil pump is blocked, which makes the cylinder oil shortage piston stuck;


(3) The shank pin of the main gear of the oil pump is twisted into the crank, which causes the oil system to break oil;


2. removal method of compressor stuck:


(1) Replace the new lubricating oil;


(2) Repair oil pump pipeline;


(3) Repair and replace the main gear shaft of oil pump;

 
   

5、 Abnormal sound in cylinder


1. The causes of abnormal sound in the cylinder are as follows:


(1) The dead center clearance in the cylinder is too small;


(2) The clearance between piston pin and connecting rod bushing is too large;


(3) The valve plate is broken;


(4) The sound of oil splashing on crankshaft crank or connecting rod big end;


2. Abnormal sound in cylinder


(1) Adjust and thicken the cylinder gasket;


(2) Replace piston pin or bushing;


(3) Stop the machine immediately and replace the valve piece;


(4) It is not necessary to stop the machine for a short time, such as stopping for inspection after several minutes;


6、 Sound in crankcase


1. The causes of noise in the crankcase are as follows:


(1) The connecting rod nut is loose;


(2) The clearance of connecting rod big end bearing bush is too large;


2. Elimination of noise in crankcase:


(1) Stop the machine and tighten it again;


(2) Replace the tiles;


7、 The compressor doesn't start


1. The reasons why the compressor can not start are as follows:


(1) Power failure, poor contact of fuse, burn out;


(2) The vertical contact of the starter is in poor contact;


(3) The temperature controller is out of balance or fails;


(4) Improper setting of pressure relay;


2. Troubleshooting for compressor failure to start up:


(1) Check the power supply and fuse;


(2) Check the starter and wipe the contact with gauze;


(3) Check the temperature indication position and check the components;


(4) Check each element or setting value of pressure relay;


8、 Insufficient cooling capacity of compressor


1. The causes of insufficient cooling capacity of compressor are as follows:


(1) The piston ring is worn or the clearance between piston and cylinder is too large due to wear;


2. Elimination method of insufficient cooling capacity of compressor:


(1) Replace new piston ring or repair and replace new parts;


9、 There is noise between the coupling of compressor and motor


1. The causes of noise between the compressor and motor coupling are as follows:


(1) The coupling of compressor and motor is improper;


(2) The key and keyway of the coupling are not matched properly;


(3) The elastic ring of the coupling is loose or damaged;


(4) The belt is too loose;


(5) Coupling bore and shaft fit loose;


2. Elimination of noise from the coupling of compressor and motor


(1) Reassemble according to the correct assembly requirements;


(2) Adjust the fit between the key and the keyway and replace the key with a new one;


(3) Tighten the elastic ring or replace it with a new one;


(4) Adjust the tension belt;


(5) Adjust and tighten the coupling.