What are the Types of Filters?

Filters

Filters are devices used to remove impurities from the medium. These devices separate solid particles from fluid (liquid or gases). When, a liquid passes through filters the solid particles are stopped on the filter while the fluid passes through it, this phenomenon clean the fluid but sometimes even after passing through the filter fluid still contains some impurities. The efficiency of a filter will depend upon the thickness of filter as well as pore size. Different filters are used in different application.

Filter Paper

It is a semi permeable paper, semi permeable paper allows only selective particles to pass through it. It is always placed perpendicular to fluid flow for separation. These filters are commonly used in chemistry and biology laboratories for different experiments. Filter paper is used with different laboratory techniques like with gravity and vacuum filtration. In gravity filtration fluid is passed through the filter paper and separation is done through gravity. In vacuum filtration vacuum is created below the filter paper with the help of vacuum pump to increase the flow rate of fluid. Increasing the flow rate increases the filtration rate of a substance.

Air Filters

Air filters are made of fibrous materials. They are used to separate solid impurities like dust, bacteria, pollen and mold from air. Air filters are used in the areas where air quality is of high importance like for building ventilation systems and engines etc. We normally use foam, and spun fiber glass elements for filtration in buildings and air crafts. Air ionizer, another example of air filters use static electric charge to attract dust particles

Oil Filters

These types of filters are designed to separate impurities from engine oil, lubricating oil, and transmission oil. Oil filters have different types like sedimentation, mechanical, magnetic, centrifugal and high efficiency (he) oil filter. Magnetic filters use magnet to separate ferromagnetic substances form oil. Advantage of using this filter is that impurities can be easily cleaned from the surface of magnet. In sedimentation impurities are separated from oil by gravity. While, in centrifugal oil filters the phenomena of centrifugation is used for separation of impurities. The dirt can damage and destroy the engine of vehicles if oil filters are not used.

Pneumatic Filters

These filters separate impurities from compressed air steam. It has two types’ primary and secondary filters. Primary filters remove water droplets and dust particles. Secondary filters remove odor, vapors, mist and fumes from air stream. Common applications of these filters are in food packaging, semiconductor packaging, air filtration, blow molding and in electronics.

Water Filters

Water filters use any chemical or biological process, or simply a barrier for purification of water. Filters use sieves and processes like ion exchange and adsorption. It has different application like for drinking water, for swimming pools, for irrigation system, and for house hold purposes, etc. Water filters also have different types: