In the process of electrophoretic coating, the heating of pretreatment solution is one of the key steps to ensure the coating quality and adhesion.

Different heating methods not only affect the stability and effect of the pretreatment solution, but also have a direct impact on energy consumption and equipment maintenance. In this paper, we will analyze in detail the common ways of pretreatment liquid heating in electrophoresis process and its selection basis.

I. Necessity of pretreatment liquid heating

In the electrophoresis process, the pretreatment stage mainly includes the steps of degreasing, descaling and phosphatizing.

The temperature of pretreatment liquid directly affects the speed and efficiency of chemical reaction. Proper heating can:
1. improve the speed of chemical reaction: heating can increase the kinetic energy of the molecules of the liquid, thus accelerating the reaction speed and improving the treatment efficiency.
2. enhance the solubility of the liquid: heating can improve the solubility of the active ingredients in the liquid, and enhance its ability to clean grease, oxides and other impurities.
3. improve the quality of treatment: stable heating can ensure that the temperature of the liquid is uniform, to avoid temperature fluctuations caused by the treatment of unstable quality.

Second, the common heating method of pretreatment solution

1. Electric heating
o Working principle: use electric heating element to convert electric energy into heat energy to heat the drug solution.
o Advantages: precise control, fast heating speed, easy to automate control.
o Disadvantages: High power consumption, high operating costs; if the electric heating element is damaged, it may lead to equipment shutdown.
2. Steam Heating
o Working Principle: Using steam generated from the boiler to pass through the heat exchanger or steam coil to heat the medicinal liquid.
o Advantages: high heating efficiency and rapid heat transfer; suitable for mass production.
o Disadvantages: Need to equip boiler and steam piping system, large investment in the early stage; high maintenance and repair cost of steam piping.
3. Hot Water Circulation Heating
o Working principle: using hot water pumps and heat exchangers to circulate hot water through the medicine pool or heating piping system for indirect heating.
o Advantages: uniform temperature, less heat loss; suitable for processes with high requirements for temperature control.
o Disadvantages: slower temperature rise, complicated initial installation; requires regular inspection and maintenance of the hot water circulation system.
4. Gas Heating
o Principle of operation: Burning natural gas or liquefied petroleum gas to produce high temperature gas to heat the liquid directly or indirectly.
o Advantages: lower cost, faster heating; suitable for processes that require high temperature heating.
o Disadvantages: relatively low safety, need strict fire and explosion-proof measures; lower precision of temperature control.

Third, the influence of the choice of heating method factors

1. Liquid properties: different liquids have different sensitivity to temperature and heat resistance, need to choose the right heating method. For example, it is preferable to use hot water circulation heating method for the liquid with strict and sensitive temperature requirement.
2. Process demand: according to the requirements of electrophoretic coating process, choose the heating method with appropriate heating speed, temperature uniformity and control precision.
3. production scale and equipment cost: large-scale production usually requires high heating efficiency and low energy consumption, such as steam heating; while small-scale production can choose low-cost electric heating or gas heating.
4. environmental protection and safety requirements: under the premise of environmental protection and safety, the choice of heating methods that meet the standards, such as electric heating and hot water circulation heating methods.

Conclusion

The choice of heating method for pretreatment liquid has an important influence on the efficiency and quality of electrophoretic coating. When selecting the heating method, comprehensive consideration should be given to the characteristics of the liquid, process demand, production scale, cost, safety and environmental protection requirements. By reasonably selecting and optimizing the heating method, the production efficiency can be improved, the cost can be reduced and the coating quality can be ensured.