The air filter consists of a filter element and a housing. The main requirements of the air filter are high filtration efficiency, low flow resistance, and long-term continuous use without maintenance.

Air filter is mainly used in pneumatic machinery, internal combustion machinery and other fields. Its function is to provide clean air for these mechanical equipment, so as to prevent these mechanical equipment from inhaling air with impurity particles during work and increase the probability of abrasion and damage. The main components of the air filter are the filter element and the housing, of which the filter element is the main filtering part, which undertakes the filtration of gas, and the housing is the external structure that provides the necessary protection for the filter element. The working requirements of the air filter are to be able to undertake high-efficiency air filtration, not to increase too much resistance for air flow, and to work continuously for a long time.

It is also used in the hydraulic system of hydraulic machinery to varying degrees, mainly to adjust the internal and external pressure difference of the oil tank of the hydraulic system.