With the development of industrial technology, coating lines are used in many fields for their high efficiency, economical safety, low pollution, and fully automated management. How to save water has become a significant issue for painting production line.
Water saving technology of painting production line includes:
1. Reverse process overflow water cleaning
After degreasing or phosphating, multiple water rinses are required to clean the chemicals adhering to the workpiece surface. In order to save water, each washing process before the coating line is designed into two water-saving units, so that the cleaning water is discharged from each process tank separately into a unit, and use the back section of the washing water supply, followed by the front section of the washing tank overflow water supply, finally discharged to the gutter to improve the utilisation rate of cleaning water.
Among the industrial designs of some paint production lines, degreasing and phosphating use their own post-cleaning water replenishment, without directly adding fresh industrial water, thus achieving further water savings. This method of water-saving has become a standard method of water washing design of the coating production line.
2. Rational adoption of new equipment to extend the tank renewal cycle
(1) Add high-pressure water-gun in the manual pre-cleaning station to reduce the handling burden of subsequent processes in the coating line.
(2) Add a suspension separation device in the hot water washing and pre-degreasing processes to remove impurities such as iron powder and silt from the tank in time.
(3) Add an oil-water separation device in the pre-degreasing and degreasing processes to separate the grease from the degreasing solution in time and prolong the service life of the degreasing solution.
(4) Increase the bag filter on the coating line to filter impurities in the tank liquid and keep the tank liquid clean.
3. Reduce the amount of liquid between coating line processes
Improve the structure of the treated object, change the hanging and conveying mode, eliminate the liquid pocketing phenomenon in the pre-processing and electrophoresis process of the coating line, reduce the amount of liquid with the workpiece, and greatly reduce the water consumption for washing after the pre-processing and electrophoresis.
4. Adopt new materials to prolong the service life of the liquid tank
The VOC emissions of traditional solvent-based intermediate and topcoat paints in coating production line are very high and cause severe pollution to the environment. Therefore, the coating industry in developed countries are researching and developing water-based coatings, powder coatings and high-solids coatings that can reduce environmental pollution, especially powder coatings that use dry spraying equipment and eliminate the water circulation system, thus achieving water and energy saving.