Surface Filtration The benefits of surface filtration are achieved by the collision of solid contaminants and the pores or passages on a simple plane or surface. The filtering benefit only occurs on this surface, and contaminants that are not retained on this surface pass through the filter medium. Surface filtration can effectively network particles larger than the pore size, but cannot network fibers and particles smaller than the pore size. The contaminant capacity of the surface filter is limited by the total surface area, and the surface area fork cannot exceed the given external dimensions. Examples of surface filter media are single-layer mesh filter membranes, stacked gaskets, wound metal tapes, and perforated metal sheets.
Deep filtration Deep filtration is achieved by the impact of solid contaminants on the matrix of successive (or deep) pores. Sand is a typical example of a depth filter. Its filtering benefits are its random adsorption benefits and the benefits of allowing solid contaminants to fall into it. The filtering is not only performed on the surface of the media, but also on the entire thickness of Jiexiu. The particles passing through the matrix change direction from time to time along the tortuous doorway. The depth filter can effectively network large pore size particles and fibers. At the same time, depending on the type and thickness of its filter media, it can also network a piece of dirt that is smaller than the very large pore size. The contaminant capacity per square inch of surface area of the depth-type filter media is too large, because the contaminants can be retained on the entire depth of the material in addition to being left on the upper layer of the media. Examples of depth filtration media include multilayer gangs, wire wound cylinders, laminated paper discs, sintered granular materials, multilayer woven fabrics, pressed or woven organic or inorganic fiber boards, laminated etched metal discs, Open-cell foam and laminated film.
