New Filtration Technology for Industrial Applications
Depth filtration is a process where solid particles are primarily separated by being deposited within the pores of the filter medium, as opposed to surface filtration. This filter medium can take various forms:
1、A bed of coarser grains, such as a layer of sand ranging from 0.3 to 5 mm deep.
2、A layer of fibers typically a few centimeters thick, such as cartridge filters sealed with resins.
3、Leaves that are a few millimeters thick, like cellulose-based filter media.
4、A granular support layer to the main filter, such as a pre-coating layer.
In depth filtration, the thickness of the filter medium is at least 100 times greater than the size of the particles being filtered. Depth filters can be constructed using wire cartridges, fiber agglomerates, porous plastic, or sintered metals. They consist of a random network of microfibers with very small granulometry, capable of retaining microscopic particles. This characteristic ensures that filtration occurs not only on the surface but also throughout the entire depth of the filter media. These media can be made of polymers, cellulose, fiberglass, or a combination thereof.
During depth filtration, contaminants navigate through a complex network of microfibers inside the filter, becoming trapped within the interlaced fibers of the filtering net. Many depth filters are constructed using folded papers of various thicknesses, maximizing the filter surface area within the same space compared to surface filters of equivalent size.