Qingzhou Weifang powered forklifts designed with the crankshaft of the engine radiator 4105 air filter filter theory: a filter: wind shield (the air vortex formation, gravity and centrifugal force so that dust precipitation in the end portion is discharged from the dust bag) secondary filter : Main filter (filter plays a major role in filtering effect of more than 95%) three filters: safety cartridge (play a supporting role in filtering, while preventing the entry of foreign matter)