company news about Electrophoresis coating ultrafiltration equipment maintenance

We can analyze the maintenance knowledge required by coating equipment according to the characteristics of electrophoretic coating equipment.

Most people know that electrophoretic coating is a water-soluble coating, with water as the solution medium, its advantage is to save a lot of organic solvents, greatly reduce air pollution and environmental hazards, safety and health, while avoiding the hidden danger of fire. E-coating equipment has high coating efficiency, small coating loss, and the utilization rate of coating can reach more than 95%. E-coating film has uniform thickness, strong adhesion, and good coating quality. All parts of the workpiece, such as inner layer, sag. weld and so on can obtain uniform and flat coating film, which solves the coating problem of complex shape workpiece by other coating methods. The disadvantage of E-coating is that only water-soluble coating can be used, and the color cannot be changed during the coating process, and the stability of coating is not easy to control when stored for a long time.

The maintenance of ultrafiltration system in E-coating equipment is the key, so we’d like to emphasize the maintenance of ultrafiltration system here.

Ultrafiltration system has two main functions: supply sufficient ultrafilter for the effective closed-circuit washing system and purify water-soluble impurities in the paint to improve the utilization rate of E-coating. The key point of management of ultrafiltration system is the amount of ultrafiltration liquid passing through. The flow rate of ultrafiltration system should be checked and recorded every day, and corresponding measures should be taken to deal with abnormalities immediately. When the amount of ultrafiltration drops to 70%, cleaning should be organized.

The reasons for the low penetration are roughly as follows:

1. Low liquid flow in the ultrafiltration equipment, change of pressure setting, lack of coarse filtration, and frequent stagnation of the equipment (stopping operation of the equipment for more than 1 hour) will reduce the transmission, and may even cause damage to the diaphragm (ultrafiltration membrane);

2. The temperature of the tank liquid is too high.

3. Filter bag blocking;

4. Filter bag particle size is too large;

5. Fail of the activated layer of the ultrafiltration membrane: the activated layer will change the polarity of the charged material to the same polarity as the tank itself. Its effect is limited by time, and its durability can reach several months under the best conditions. After the activation layer fails, it is necessary to restore its function by means of cleaning. When cleaning, the cleaning liquid should be configured strictly in accordance with the formula and proportion, and the cleaning procedure should be carried out carefully, otherwise it will cause the failure or scrap of the ultrafiltration membrane.

Three common cleaning methods

General daily cleaning (once a month)

1. Confirm that the cleaning tank is filled with pure water or ultrafiltrate.
2. Close the inlet and outlet valve of the film group and open the inlet and outlet valve of the film group cleaning.
3. Close the valve between the ultrafiltration water collecting manifold and the ultrafiltration water tank, and open the valve between the water collecting manifold and the cleaning water tank.
4. Open the inlet and outlet valves of the cleaning pump and start the cleaning pump.
5. Use the ultrafiltrate/pure water from the cleaning tank to beat the paint in the membrane group back to the electrophoresis tank; About 2/3 of the volume of the cleaning tank.
6. Close the paint liquid inlet and outlet valve of the film group and open the cleaning inlet and outlet valve of the film group.
7. Fill the cleaning tank with pure water.
8. Stop the pump for about 240 minutes after circulating cleaning.
9. Check whether the circulating liquid contains a large amount of paint, which can increase the number of cleaning.
10. Stop cleaning and use in line.

Chemical cleaning:

1. Add pure water to the cleaning box to replace the recycled solution, which is generally (Butyl glycol 30%+5%actic acid +65%water,or the solvent NH01 additive 30%+NHF-02 additive 25%+ pure water 45%);The temperature of cleaning solution should not exceed 45C.
2. After the regeneration solution is cleaned ,it is necessary to repeat the general daily cleaning method and clean it with pure water

Sterilization clean:

1. Add pure water to the cleaning box to replace it with fungicide (the proportion is in accordance with the fungicide instructions); The temperature of cleaning solution should not exceed 45 C.
2. After sterilization and cleaning, it is necessary to repeat the general daily cleaning method and clean it with pure water.

Remember: The following conditions will cause fatal harm to ultrafiltration membrane components and will no longer cover the normal operation and quality of the equipment.

1. Sudden shutdown and power failure in the workshop.
2. The ultrafiltration membrane component cannot be cleaned in time after shutdown.
3. Fail to operate according to regulations when starting or stopping.