SERVICES

A filter where the substance to be filtered and to be freed from impurities is water is a water filter. The basic methods of filtration are applicable to water filter along with other chemical and biological processes. Filters are used to purify the water to different extents for irrigation, drinking water, etc. Water filters use techniques such as sieving, adsorption, ion exchanges. The various types of water filters include media filters, screen filters, disk filters, slow sand filter beds, rapid sand filters and cloth filters. For home use point-of-use filters are used. They include granular activated carbon filters (GAC) which is used for carbon filtering, metallic alloy filters, microporous ceramic filters, carbon block resin (CBR) and ultra filtration membranes. Portable water filters are also available. A water filter can be made from local materials like grass, charcoal and sand. But these do not purge the water of micro-organisms and pathogens.

Air filters are of two types - particulate air filter and chemical air filter. The former constitutes of fibrous substances which remove solid particulates such as dust, pollen, mold, and bacteria from the air, while the latter cleanses the air of volatile compounds or gases with the help of an absorbent or catalyst. Air filters are generally used in building ventilation systems and in engines where air quality is important. Usually foam, pleated paper, or spun fiberglass elements are used in air filters. A more sophisticated method is that of using air ionisers which use substances with a static electricity charge on them which attract dust particles.

Press filters are used to separate out solid and liquid. They are industrial machines. This solid/liquid separation is obtained through filtering cloths and plates.

Oils like engine oil, transmission oil, lubricating oil contain many impurities. Oil filter is used to filter these impurities. These are mainly used in hydraulic machinery.