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Six Points for Maintenance and Maintenance of Screw Refrigeration Unit

Date:Mar 27, 2020

The main contents of screw refrigeration unit maintenance include daily maintenance and regular maintenance.  Regular maintenance can ensure the long-term normal operation of the refrigeration unit, prolong the service life of the refrigeration unit, and at the same time can save energy consumption for refrigeration.  For screw refrigeration units, operation records shall be kept to record the operation of the refrigeration units, and maintenance technical files shall be established.  Complete technical data are helpful to find hidden trouble and take measures as early as possible to prevent the trouble.


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1, screw refrigeration compressor maintenance and maintenance

Screw refrigeration compressor is a very key component in screw refrigeration unit. The quality of refrigeration compressor is directly related to the stability of the unit.  If the refrigeration compressor fails.  As the installation accuracy of screw refrigeration compressor is required to be high, the manufacturer is generally required to carry out maintenance.


2. Cleaning of condenser and evaporator

As the cooling water of the water-cooled condenser is an open circulation loop, the tap water commonly used is recycled through the cooling tower.  When the content of calcium salt and magnesium salt in water is large, it is easy to decompose and deposit on cooling water pipes to form scale, which affects heat transfer.  Excessive scaling will also reduce the circulation cross section of cooling water, reduce the amount of water and increase the condensation pressure.  Therefore, when the quality of the cooling water used is poor, the cooling water pipe shall be cleaned at least once a year to remove scale and other dirt in the pipe.  There are usually two methods for cleaning condenser water pipes: one is to use a special pig gun to clean the pipes;  One is to use a special cleaning agent for circulation flushing, or to fill it in cooling water, and then change the solution after 24 hours until it is washed.


3. Replacement of lubricating oil (refrigerant oil)

After the refrigeration unit is used for a long time, the oil quality of lubricating oil (refrigerant oil) will deteriorate and the impurities and moisture inside the oil will increase. Therefore, the oil quality should be observed and checked regularly.  Once problems are found, they should be replaced in time. The grade of the replaced lubricating oil (refrigerant oil) must conform to the technical data.


4, dry filter maintenance

Drying filter is an important component to ensure the normal circulation of refrigerant.  Because water and refrigerant are immiscible, if the system contains water, it will greatly affect the operation efficiency of screw refrigeration unit, so it is very important to keep the system dry, and the filter element inside the drying filter must be replaced regularly.


5. Verification of Safety Valve

The condenser and evaporator on the screw refrigeration unit belong to pressure vessels. According to regulations, a safety valve should be installed on the high-pressure end of the refrigeration unit, i.e. the condenser body. Once the refrigeration unit is in an abnormal working environment, the safety valve can automatically relieve pressure to prevent possible injury to human body caused by high pressure.  Therefore, the regular check of safety valve is very important for the safety of the whole screw refrigeration unit.


6, refrigerant filling

If there are no other special reasons, the general refrigeration unit will not produce a large number of leaks.  If a certain amount of refrigerant leaks due to improper use or after maintenance.  The refrigerant needs to be added again.  When filling refrigerant, attention must be paid to the label of refrigerant used by the refrigeration unit.


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