The type of filtration the air filter uses depends on the machine's use and environmental conditions. The general automobile uses the paper filter filters, or the oil bath-filter combination filter. The internal combustion engines for tractors, tractors and engineering machines require a combination of two or three filtration filters because of the dust in the working environment. Marine internal combustion engine is often used as filter of paper filter or metal filter because of its cleaner environment. Reciprocating air compressors are based on the size of the exhaust volume of different metal filter, the exhaust volume is less than 12.3-meter/min of the reciprocation compressors are mostly paper filter filters, and with the internal combustion engine filter general.
Most of the reciprocating compressors with medium exhaust are made of metal filter. In order to improve the dust-absorbing ability of metal filter, it is often applied on the metal filter to apply viscous oil or oil bath. A combined filter with a few metal filters is used when the exhaust capacity is greater than 40.3-meter/time-sharing. Oil-free lubrication of the compressor can not be used, but should use dry filter.