Hundred-level ultra-clean workbench is mainly used to purify the air with high-efficiency filters, its high-efficiency filters are used with a certain service life, need to be replaced regularly. If the bench itself is in a cleaner environment, such as GMP workshop, then the replacement frequency is low; if only ordinary laboratory, should be 2 years to change the high-efficiency filter to ensure its effectiveness. The length of service life of the ultra-clean bench is related to the cleanliness of the air. In temperate regions can be used in the general laboratory ultra-clean table, however, in tropical or subtropical regions, by the atmosphere contains a large number of pollen, or dusty areas, the ultra-clean table should be placed in a better indoor use of double doors. In any case should not be ultra-clean table air inlet cover to the open door or window, so as not to affect the service life of the filter. Indoor air through the pre-filter primary filtration, pressed by a small centrifugal fan into the static pressure box, and then through the air high-efficiency filter secondary filtration, from the air high-efficiency filter out of the surface of the clean air flow with a certain and uniform cross-section of the wind speed, you can exclude the original air in the work area, dust particles and biological particles away, in order to form a sterile and high-clean working environment.