Two Basic Types of Filter Media
Filter media can be reduced to two basic categories: Non-woven cellulosic blend, and synthetic polyester media (or polyester-silicon blend).
Non-woven cellulosic blend media is the most economical choice for dry dust collection applications at operating temperatures up to 160°F. Media coatings can be employed to enhance moisture resistance, but cellulose media in general is not as resistant to moisture as synthetic polyester.
Synthetic polyester media is a lightweight and washable media that can handle dry applications with operating temperatures from 180°F to 265°F. These filters are washable and can recover from moisture exposure, but are not intended for wet applications.
Common Media Coatings
Flame retardant media is treated with a chemical which adds fire retardant properties for use when there is risk of a fire or explosion.
Conductive or anti-static filters typically employ a carbon or aluminized coating and are used where dusts generate static charges that require dissipation.
Nano fiber coatings can enhance the filter media, boosting efficiency and promoting surface loading of fine dust particles to keep the particles from penetrating deeply into the base media. This translates into better dust release during cleaning cycles and lower pressure drop throughout the life of the filter, which saves energy and promotes a longer filter life.
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| Correct filter choice for your application is important to ensure low total cost of ownership, operating efficiency, and filter life. |
Compared to standard media, nano fibers offer higher filtration efficiencies as well as better energy performance, superior cleanability, and greater resistance to wear from pulse-cleaning. Because of these benefits, experts believe nano fiber media will become the standard in the future.
Open Pleated Media
Tightly pleated filter media tends to trap dust within the pleats. This causes wear on the filter media and increases the pressure drop across the filter over time. Open-pleated media uses pleat separators to allow the collected dust to release from the filter during cleaning cycles. This keeps the air resistance low through the filter which improves operating efficiency, filtration efficiency, and extends filter life. Nano fiber coatings can enhance the filter media, boosting efficiency and promoting surface loading of fine dust particles to keep the particles from penetrating deeply into the base media. This translates into better dust release during cleaning cycles and lower pressure drop throughout the life of the filter - saving energy and promoting a longer filter life.
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| Open pleats breathe easy (green) while tightly packed pleats (blue) trap dust and increase pressure drop across the filter. |
A wide pleated filter will often contain less total media area than a tightly pleated model, but the total square footage of the media is not what you want to focus on. It's the total usable media area in a filter that counts.
Proper Testing of Dust
In order to select the most efficient filter for your application, you must first determine the properties of your dust. Dust can be tested to determine particle size distribution (down to the sub-micron range), moisture content, explosivity, adhesion, and cohesion. The long established process of dust testing has been used by professionals to make informed decisions on the design of dust collection systems.
Evaluating the Total Cost of Ownership
When selecting a cartridge filter media, you should also be aware of the cost of owning and operating the filters on your application. A Total Cost of Ownership evaluation can help you determine which filters are more economical in the long run, and may show that a more advanced filter media will provide longer life and lower overall operating cost.
