Working Principle of Self-cleaning Screen Changer
The molten plastic material (1) is conveyed into the filtration chamber (2) and goes through two screens (3) facing each other. Between the two screens there are two scrapers(4), equipped with blades, which rotates to remove the impurities from the screens. The core of the scraper receives the impurities, which is then transferred to the independent discharge screw (6) then ejects it. The plastic filtered material rejoins the output channel (8) to move on to the next process.
The filtration precision of the self-cleaning screen changer can only reach 120 mesh, which is unable to meet many high-precision filtration requirements. For instance, in granulation production, the self-cleaning screen changer is usually used as the first-stage filtration to remove large particle impurities. It is then combined with a plate-type or piston-type screen changer as the second-stage filtration to improve the filtration precision. However, after two-stage filtration, the pressure of the melt flow will drop significantly, so a melt pump needs to be equipped for pressure stabilization and boosting, ensuring the continuous and stable output of raw materials. Therefore, in the granulation production line, the combination of "self-cleaning screen changer + plate/plunger screen changer + melt pump" forms an efficient and high-precision filtration system.
