The air filter is a filter, also called air filter cartridge, air filter, style, etc. Mainly used for air filtration in engineering locomotives, automobiles, agricultural locomotives, laboratories, aseptic operating rooms and various precision operating rooms.

The engine needs to suck in a large amount of air during the working process. If the air is not filtered, the dust suspended in the air is sucked into the cylinder, which will accelerate the wear of the piston group and the cylinder. Larger particles enter between the piston and the cylinder, causing a serious "cylinder" phenomenon, which is especially severe in dry and sandy working environments. The air filter is installed in front of the carburetor or the intake pipe to filter out dust and sand in the air to ensure sufficient and clean air in the cylinder.

According to the filtration principle, the air filter can be divided into several types: filter type, centrifugal type, oil bath type and composite type. The air filter filters commonly used in engines mainly include inertial oil bath air filters, paper dry air filters, and polyurethane filter air filters. The inertial oil bath air filter has been filtered by inertial filter, oil bath filter and filter filter. The latter two air filters are mainly filtered through the filter. Inertial oil bath air filter has the advantages of low air intake resistance, can adapt to dusty and sandy working environment, and has long service life. It has been used in various types of automobile and tractor engines. However, such air filters have been gradually eliminated due to their low filtration efficiency, heavy weight, high cost, and inconvenient maintenance. The filter element of the paper dry air filter is made of resin-treated microporous filter paper. The filter paper is porous, loose and folded, has certain mechanical strength and water resistance, and has high filtration efficiency, simple structure, light weight and cost. Low and easy to maintain, it is the most widely used automotive air filter. The filter element of the polyurethane filter air filter is made of soft, porous and sponge-like polyurethane. It has strong adsorption capacity. This air filter has the advantages of paper dry air filter, but the mechanical strength is low. It is widely used. The latter two air filters have the disadvantage of a short service life and unreliable operation under harsh environmental conditions.

Various air filters have their own advantages and disadvantages, but inevitably there is a contradiction between the amount of intake air and the efficiency of filtration. With the in-depth study of air filters, the requirements for air filters are also increasing. Some new air filters have emerged, such as fiber filter air filters, duplex filter material air filters, muffle air filters, and constant temperature air filters to meet the needs of engine operation.

For the air filter, it is used for the construction machines as following brand:

CATERPILLAR, KOMATSU,VOLVO,HITACHI,HYUNDAI,DOOSAN,FIAT-HITACHI,JCB,KOBELCO,SUMITOMO,KATO,CASE,MITSUBISHI,TATA-HITACHI,NEWHOLLAND,JOHN-DEER,KUBOTA, LIEBHERR, TAKEUCHI,KAWASAKI,SANYI,LIUGONG,XCMG,SHANTUI,ZOOMLION;