The fan can either suck or blow, so it can produce overpressure or underpressure depending on the application. When used as a blowing-type filter fan, the filter fan should be installed at the bottom of the control cabinet, and the outlet filter should be installed in the upper area; If the filter fan is used for suction, it should be installed in reverse. In this way, the heated air is well expelled. The overpressure step in the control cabinet reduces the entry of dust. Filter fan should always be used with suitable outlet filter.