Round air filter cartridges are always compressed during the working of engine, since the air filtered flows through usually inwards to get directly into the engine by inlet pipes. If the filtering cartridge is relatively high, or the engine has a large capacity and therefore a huge requirement for air, the cartridge is exposed to significant compressive forces. Permanent deformation or even damage to the surface could be avoided by application of reinforcement elements. Reinforcement is done by using nets made of metal protected from corrosion. It improves the cartridge rigidity and protect from filter subsidence due to pressure difference before and after the filter during intensive work of the engine.
Round air filter cartridge