How to deal with the fouling of the heat exchange tubes of the evaporator in the screw unit

I. Overview 

The evaporator of the screw unit is one of the core components of heat exchange. It transfers the heat from the interior to the exterior through heat exchange with the refrigerant, achieving the purpose of cooling. However, due to various reasons, such as water quality and environmental factors, a layer of hard scale will gradually accumulate on the surface of the heat exchange tubes, thereby reducing the heat exchange efficiency and affecting normal operation. 

II. Hazards of Scale Formation in Evaporators 

Affects the heat exchange efficiency. 

The deposits adhering to the surface of the heat exchange tubes will increase the resistance of the pipeline, affect the smooth flow of water, reduce the efficiency of heat transfer, and lead to a decrease in the cooling capacity. 

2. Increase the energy consumption of the equipment. 

Due to the decline in heat exchange efficiency, the equipment will subsequently require increased power consumption. Moreover, prolonged operation will also increase the failure rate and maintenance costs of the equipment. 

3. Shorten the lifespan of the equipment. 

When the scale buildup is severe, the surface area of the heat exchange tubes gradually decreases, resulting in a reduction of the heat exchange area. This, in turn, affects the cooling effect and accelerates the wear and tear of the equipment. 

III. Handling Methods 

Mechanical cleaning 

Mechanical cleaning is one of the most common methods for dealing with scale deposits on the heat exchange tubes of evaporators. It mainly involves using brushes or wire brushes to remove the accumulated scale deposits on the surface of the pipes. The advantages are that the cleaning effect is good, the operation is simple, and the cost is relatively low. However, due to the impact of the mechanical process on the pipes, it may cause damage to the pipes, so careful operation is required. 

2. Chemical Cleaning 

Chemical cleaning involves spraying a chemical agent onto the surface of the pipeline, causing the scale inside the pipeline to react with the chemical agent and completing the cleaning process. This method is suitable when the temperature of the evaporator is relatively low and has the advantage of good cleaning effect. However, the process of using the chemical agent poses certain risks to personnel, so proper protection measures should be taken. 

3. Ultrasonic Cleaning 

Ultrasonic cleaning uses high-frequency and high-energy ultrasonic cleaning solution to remove scale from the pipes. It has the advantages of excellent cleaning effect, no damage to the pipe surface, and no need to disassemble the pipes. It is suitable for cleaning when the evaporator temperature is high. 

IV. Conclusion 

Maintaining the fouling of the heat exchange tubes in the evaporator of the screw chiller is crucial for ensuring the normal operation of the equipment and extending its service life. The three treatment methods mentioned above can all effectively solve the problem of fouling in the heat exchange tubes. Appropriate cleaning methods should be selected based on the actual situation.