Scraper Type Self-cleaning Filter

JX Filtration October 2, 2022 Scraper Self-cleaning Filter

Background:

As an new type of filter which is developed in the end of 1970, self cleaning filters has a lot of advantages such as self-cleaning, low pressure loss, etc. For now, it has been developed multiple types like suction type self-cleaning filter, scraper type self-cleaning filter, rotating arm type self-cleaning filter and backflush type self-cleaning filter. Among these type filter, scraper type self-cleaning filter is better than other types when they are tested in filtration of viscosity material. Scraper self-cleaning filter is suitable in paper making, metallurgy, chemical industries. By using the scraper, the scraper self-cleaning filter can remove the sticky particles on filter element. Therefore, as the key part of scraper self-cleaning filter, the scraper affect mainly the sewage removal.

Structure and operating principles:

When material enters the scraper self-cleaning filter, the particles which is smaller than the mesh size will pass through filtrate screen and will be drained from filter outlet with material after filtration. As for some of the particles larger than mesh size, they will deposit directly on the bottom of the filter under gravity and water strength, and the other part of particles will be sticky with filtrate screen. When the particles on the filtrate screen accumulate to certain thickness, the pressure difference of inside and outside of filtrate screen will be increase, and pressure drop loss will increase. When pressure drop loss exceeds the loss required by filtration system, the pressure difference sensor will send signal to control box, launch motor, and then the scraper will be operated to clean the particles on filtrate screen. During cleaning particles, the scraper will contact with filtrate screen under the strength of centrifugal force and spring force, at the same time, due to the normal force between scraper and filtrate screen is small (almost 0), the scraper will fully clean the particles and impurities under the tangential force. And to avoid that impurities will be forced to filtrate screen under the normal force, the particles cleaned by the scraper will also deposit on the bottom of filtrate under gravity and hydraulic cyclone, and when the particles on the bottom reach to certain degree, the control box will open the drain valve on the filtrate bottom to remove particles.