① Cake Filtration:In the initial stage of filtration, the filter medium only traps large solid particles, while smaller particles pass through with the filtrate. After the initial cake layer is formed, it plays a major role in filtration, trapping both large and small particles. Examples include plate and frame filter presses.
② Deep Bed Filtration: The filter medium is thicker, and the suspension contains fewer solid particles, with particles smaller than the pores of the filter medium. During filtration, particles are adsorbed within the pores. Examples include porous plastic tube filters and sand filters.
③ Screwing Filtration:The solid particles trapped in this filtration are larger than the pores of the filter medium, and the filter medium itself does not adsorb solid particles. Examples include rotary drum filters that remove coarse impurities from wastewater. In actual filtration processes, these three methods often occur simultaneously or sequentially.
