When the gas containing dust enters to dust remover, the dust powder endures two steps of filter, first of all, along with the reduce of airflow speed and alteration of airflow direction, biggish one sedimentates in dust collection chamber (Model A and Model J) due to gravitation and inertia. To Model B products, it sedimentates in users’ material storehouse, hopper and other equipments; while tiny one remains on the bag wall, and the clean air after purifying is sent back to workshop relying on centrifugal force to reduce thermal loss.