More about Filters

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Filters are a staple of industry. They are used to keep harmful objects from passing through while letting other material through. There are three main kinds of filters, each of which holds a purpose in a different medium: Air, pneumatic, and water.

Air filters remove harmful substances from the air, such as mold, bacteria and dust. They are used in ventilation systems and internal combustion engines, or anywhere else that the air needs to be clean. They are made of a variety of material, including cotton, paper and foam. Paper, because it is relatively inexpensive and disposable, is used in consumer vehicles. The disadvantage is that paper is not very porous, which allows for good filtration but not very good air flow. Cotton is used in vehicles as well, when it is important to retain air flow while filtering out substances. It is reusable, which makes it more expensive. Foam filters are used in everything from truck and motorcycle engines to vacuum cleaners. They have an advantage in that they can be used either wet or dry (which makes them washable as well).

Pneumatic filters are a kind of air filter, but they work in a compressed air stream, which would be found in air brakes and pneumatic tools. The pneumatic filter traps particles as tiny as five micrometers that could damage pneumatic tools, such as dirt, water droplets and particles of lubricant. They often employ a secondary filter to trap even smaller particles, including vapor and and odors.

Water filters work to remove harmful contaminants from water. Most domestic use involves coconut husk as the medium of filtration; it absorbs the impurities (including bacteria and mold) as the water passes through. A reverse osmosis water filter mimics the function of an air filter by allowing water to pass through a fine membrane, which takes everything from the water. Other kinds of water filters utilize electricity to either boil the water or charge it through ionization, thus separating the water into alkaline and acidic components.