Die evaporator is where heat exchange occurs between the refrigerant and the coolant. After long-term use, scale, microbial mucosa and other impurities will accumulate in the evaporator of the Industriekühler. If it is not cleaned in time, it will affect the heat exchange efficiency, and may even corrode the equipment and shorten the service life of the cooling system. This article introduces 2 common methods and detailed steps for cleaning the evaporator.

Tips

• Cleaning must be performed by professionals.
• Water and electricity must be turned off before cleaning.
• Wear protective equipment such as gloves, masks and goggles.

Chemical Cleaning

Chemical cleaning is usually used for shell and tube evaporators that are not convenient to disassemble, and has a good cleaning effect on thick scale and biofilm. Evaporators of different materials have different corrosion resistance to cleaning fluids. To prevent corrosion of equipment, it is essential to select specialized cleaning agents. However, strong acids such as concentrated hydrochloric acid should never be used on any type of evaporator, as they are highly corrosive to metals.
 
Suitable cleaning tools can help improve cleaning efficiency. You need to prepare a circulation pump, a bucket, pH test paper, a pressure gauge, a thermometer, and protective equipment. Before cleaning, you need to close the water inlet and outlet valves to drain the residual liquid in the evaporator.
 
1. Install the cleaning circulation system
Connect the circulation pump to the evaporator and the water bucket tightly to ensure that there is no leakage.
 
2. Rinse with clean water
Pour clean water into the water bucket and start the circulation pump, let it run for about 20 minutes to drain the water. This step can help drain the liquid in the evaporator and check whether the connection between the pump and the evaporator is tight.
 
3. Configure the cleaning liquid
Choose the appropriate type and ratio of cleaning liquid according to the material of the evaporator, and control the temperature and pH value within the appropriate range. The general liquid temperature is room temperature, preferably not more than 40℃. The pH value should be adjusted according to the material of the evaporator.
 
4. Circulation cleaning
Start the circulation pump after adding the cleaning liquid to the bucket. Circulate in both directions for a total of 30 to 60 minutes. During this period, you need to observe the state of the cleaning liquid and test the pH value every 10 minutes. If the pH value rises, it means that the reaction is almost complete, and the darkening of the liquid indicates that the dirt is falling off. It is necessary to decide whether to extend the circulation time or replace the cleaning liquid according to the cleaning situation.
 
5. Neutralization and cleaning
Generally, after the acid cleaning is completed, in order a weak alkaline solution is used to neutralize any remaining acid and prevent corrosion to control the pH value in the evaporator at 6.5~8.
 
6. Drainage
After neutralization and cleaning, use a large amount of clean water to repeatedly rinse the system, and continue rinsing until the discharged water is free of foam and impurities, and the pH value is close to neutral.
 
7. Inspection and reset
Remove the inspection port to confirm whether the dirt has been completely cleaned, and whether the joints, such as the sealing ring and valve are loose. After confirming that there is no problem, reinject the coolant and exhaust until there are no bubbles. After the filling is completed, start the chiller and check whether the outlet water temperature and evaporation pressure are normal. If there is no abnormality, then congratulations on completing a chemical cleaning.

Mechanical Cleaning

Physical cleaning does not use chemical cleaning agents, but removes dirt from the surface of the evaporator by disassembly, brushing, high pressure, vibration, etc. This method is suitable for use when the scale is not serious or the evaporator material is easily corroded. The tools that need to be prepared include pipe brushes, brushes, endoscopes, high-pressure water guns, air compressors, and protective equipment. The specific amount should be increased or decreased according to the material and type of the evaporator.

Cleaning the shell and tube heat exchanger

First, cut off all power supplies and close all water valves to drain the residual liquid in the evaporator from the drain. Open the covers at both ends of the evaporator to expose the two ports of the heat exchange tube. Use a special brush to scrub the pipes and repeatedly rinse with a high-pressure water gun until the flushed water is clear and free of impurities. The pressure of the high-pressure water gun must not exceed the pressure of the pipe. After cleaning, use an endoscope to check the cleaning condition in the pipe. After confirming that it is clean, use compressed air to blow dry the pipe. The last step is inspection and assembly.

Cleaning the plate heat exchanger

After turning off the water and electricity and draining the residual liquid, loosen the fastening bolts of the plate heat exchanger and remove the plates. Be sure to arrange and label the plates to prevent the wrong order during assembly. Check the status of the gaskets and plates. If there are any abnormalities, you can replace them while cleaning. Use a non-metallic brush dipped in clean water or cleaning fluid to scrub, and use a high-pressure water gun to rinse the board surface. After rinsing, let it dry naturally or air dry, assemble it in the original order, and check the sealing. If there is no abnormality, it can continue to be put into use.

Schlussfolgerung

Still unsure about how or when to clean your equipment? We’re here to help! LNEYA build chillers and know exactly how to keep them humming. Whether you need technical support or a customized cooling solution, contact our expert team today.

FAQ