What are the common faults of screw chillers? How to solve it?
There are many industrial application scenarios for screw chillers, such as machinery industry, food refrigeration, pharmaceutical and chemical industry, beverage and wine brewing, and so on. There are roughly two classification methods. One is divided into air-cooled and water-cooled screws according to the way of condensation; the other is divided into single-screw and twin-screw units according to the type of compressor.
Screw compressor is a type of compressor with adjustable energy. The main components include rotor, bearing, body, energy regulating device, etc. Through the rotation of the rotor, a periodic volume change is formed to realize gas compression and work.
For the screw chiller, its operation is stable, but due to other reasons such as year-round operation or inadequate maintenance, it will also cause common failures of the screw chiller. The following editor of Kadley combines industry experience to introduce to friends.
Common failure type 1: high voltage failure
There are usually several reasons for high voltage failure:
1. The water temperature is too high. Mainly occurs in high temperature seasons, cooling tower fan failure, cooling tower valve, cooling pipe blockage, will cause the cooling water to dissipate poorly, and the water temperature will rise. A high voltage alarm is triggered.
2, too much refrigerant. Refrigerant is a substance compressed in the refrigerant system. Too much addition will cause high suction and discharge pressure. Causes the compressor current to rise and high pressure appears.
3. Lack of cooling water. If the system lacks cooling water, the system water flow will decrease, and the pressure difference between the inlet and outlet water pressure of the unit will decrease. The temperature difference increases, causing high pressure.
4. The condenser is malfunctioning. Condenser fouling and blockage will cause poor cooling water system operation, poor water flow, reduced water flow, reduced heat dissipation area, and low condensation efficiency. Especially common failure causes of chillers that have not been cleaned for a long time.
Common fault type 2: low voltage fault
There are several reasons for low voltage failure.
1. The refrigerant is insufficient. If the refrigerant is added less, the operating pressure of the refrigerant system is lower, which causes the compressor current to decrease and a low pressure failure occurs.
2. The cooling water temperature is too low. The usual solution is to close the cooling tower valve and reduce the cooling water flow to increase the cooling water temperature. Especially in winter, it will also cause the temperature of the refrigerating oil to decrease, affect separation, and cause low pressure.
3. Too little chilled water. Usually, the reasons for insufficient chilled water flow are air in the system, water in the system, and damage to the water pump.
Other failures: such as blockage of expansion valve, blockage of evaporator, insufficient refrigerant, etc., can also cause unit failure or shutdown. Pay special attention to the temperature of the compressor during operation to avoid overheating.
The following are common methods for troubleshooting.
1. Clean the condenser and evaporator.
Common faults are internal scaling, rusting, corrosion, etc., causing internal blockage and water pollution. Especially in the operating environment with poor cooling water quality, a water processor should be installed or the cleaning frequency should be increased.
2. Replace the lubricating oil and filter drier.
Long running time of lubricating oil will cause deterioration of oil quality, infiltration of moisture and impurities, and poor lubrication. Overheating of the compressor occurred, causing serious failures later. Therefore, the lubricating oil and filter drier should be replaced regularly.
3. Regularly check the safety valve
The condenser evaporator container is equipped with safety valves to avoid accidents caused by overpressure. Therefore, the safety valve should be regularly checked for its working efficiency and whether it is normal. Avoid accidents caused by damage.
