Cartridge filters are tubular filtration devices that can be used in different industries with different filtration requirements. Cartridges are housed in filter housings or casings, and they are used to remove unwanted contaminants, particles, and chemicals from liquids. The optimal contamination level for cartridge filters should be less than 0.01% by weight.
The various kinds of available cartridge filters divide and conglomerate under two basic types, namely; Surface filters and Depth filters, both of which are self-explanatory by their names. During usage, the surface filter does not allow passage of suspended solids and contaminants but instead restricts the particles on the surface via its thin layers. Depth filters, on the other hand, consist of multiple layers or thicker media that, when fluid passes through it, retain suspended solids within the media.
Types of Cartridge Filters by Construction
1. Wound Cartridge Filter
Constructing this type of depth cartridge filter is firstly by weaving and twisting microfiber together, most likely polypropylene, thereby forming a yarn. The manufacturers then wound this formulated yarn around a core to create a gradient assembly. This structure is usually only prominently efficient when the type and quality of yarn and the manufacturing mechanisms and processes are optimal. Another name for it is the string-wound filter cartridge.
2. Melt Blown Cartridge Filter
These types of filters are also a type of depth cartridge filters. Industries fabricate them from the melt blowing process, which mainly involves melted granules of polymers such as polypropylene, getting extruded from small outlets onto a rotating shaft. When it comes to choosing the right melt blown filters, the factors to watch out for are the contaminant removal rate or efficiency, as well as the functional lifespan of the filter.
3. Air Filter Cartridge
The air filter cartridge can achieve high filtration efficiency for nonviscous dust. Even if the ambient temperature is lower than zero temperature, the filter element can maintain constant filtration capacity. The high mechanical stability of the material ensures the long service life of the filter element. The structure of the dust collector ensures the compatibility of its existing filtration system. PTFE coated filter has the advantages of membrane filtration and rigid body filtration.
4. Pleated Type Cartridge Filter
These types of filters are typically surface-type cartridge filters. However, modernization has brought about the incorporation of thicker media. That implies that these types are efficiently capable of depth and surface filtration. Simply put, pleated filters are filter elements constructed using filter media sheets that have undergone pleating.
5. Sintered Cartridge Filter
This is a depth-type depth of cartridge filter, and in simple terms, they are filter elements that have gone through the sintering process. Sintering is a process where scientists use metallic or polymeric materials in their powdered form to shape a tubular filter element. Sintered filters are usually corrosion resistant and have high temperature and pressure resistance, which reveals their high level of robustness. (Check our “Sintered Metal Cartridge Filter“)
6. Wire Mesh Cartridge Filter
Wire mesh filters refer to a fabrication consisting of grids that materialize because of accurately woven wires in shute direction with small spacing between crossing wires. These filters exhibit this grid pattern in single or multiple layers. During usage, fluid in need of filtration tries to navigate through the convoluted route of the filter element, and there is an obstruction for any suspending solid. It is, however, essential to note that when grids such as these undergo pleating, it results in the advantage of a larger surface area.
Cartridge Filters vs Bag Filters
As earlier stated, cartridge filters are either depth filters or surface filters, the difference between them being that surface filters hold the suspending solids during filtration, on the surface of the filter element. In contrast, the thick layers of the depth-type filters inhibit the suspending solids within the matrix of the filter element. Nonetheless, whenever the filter of cartridge filters clog from consistent use, they require replacement by design.
Both categories of cartridge filters have different fields of application. Surface filters seem to excel best when filtrating fluids that have solid particles within a small size range.
The larger surface area of filters generally happens to be indispensable to an efficient, long-lasting filter with high solid retention capacity. Therefore, a pleated surface is considerably better than other filters when it comes to filtrating deposits of similarly small-sized particles.
Depth-type filters find their advantage when filtering fluids that require depth or thickness.
Bag filters typically find their usage in industries that require dust removal. They descriptively consist of an external surface that may interchange functions, i.e., the separation of particles using bag filters may occur in the internal surface of the filter or on the outer surface. Still, typically, bag filters trap the particles in the inner surface of the filter and are usually surface-typed.
Contrary to cartridge filters, producers do not construct bag filters with any intent for replacement when clogged. However, as previously mentioned, most industries use bag filters for dust removal and other gaseous filtration. As such, they can clean some of these bag filters using processes such as ‘backwashing’ or mechanical shaking.