When detecting, all Windows in scaled image series pass through the coarse filter and the main classifier, then merge, locate and output to original image.

A disposable non-woolen filter, and a panel type washable coarse aluminum filter are installed in the front panel of return air duct of each room, to trap powder generated, if any.

This paper expounds the adaptibility of coarse sand filter with simultaneous air and water backwash to tertiary filtration plant.