Air Filters

An air filter is a device which removes contaminants, often solid particles such as dust, pollen, mold, and bacteria from air. more...

They are often used in internal combustion engines, gas compressors, diving air compressors, ventilation systems, and any other application where air quality is important.

Engine intakes tend to use either paper, foam, or cotton filters. Some buildings, as well as planes and other man-made environments (e.g., satellites and space shuttles) use foam, pleated paper, or spun fiberglass filter elements. Another method uses fibers or elements with a static electric charge, which attract dust particles.

Types of air filters

There are four main types of mechanical air filters: paper, foam, synthetics and cotton. Though all have varying degrees of practicality, it is generally recognized that cotton air filters are best because of their durability and technological advantages.

Paper

Paper filters are generally used in automobiles because they are inexpensive and disposable. Due to the characteristics of paper, good airflow is sacrificed for good filtration.

A example of pleated-paper air filters designed for in-duct use with home heating, ventilation, and air conditioning (HVAC) systems is the 3M "Filtrete" line of products.

Synthetics

Polyester fiber is commonly used to make web formations used for air filtration. Polyester has a high temperature rating (abut 250 F)and is widely used in commerical, industrial or residential applications. Polyester can be blended with cotton or other fibers to produce a wide range of performance characteristics. In some cases Polypropylene, which has a lower temperature tolerance, is used to enhance chemical resistance. Tiny synthetic fibers knows as micro-fibers are used in many types of HEPA (High Efficiency Particulate Air Filter) filters.

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