An inspection system inspects appearances of a plurality of worked products held by a sheet-like inspection target sheet, and includes an image processing station provided at a first location and defect detection stations provided at one or a plurality of second locations away from the first location. A dataset corresponding to a backup copy is examined to determine if the dataset has changed from a previous backup operation. The valves comprise a cantilevered pair of closely adjacent thin ledges, nicknamed \u201cvalve leaflets,\u201d that resemble needle-nose pliers. A plurality of semiconductor devices are laid one over after another, thereby constituting a semiconductor module. Alternatively, the variable venturi may have a movable end flap that selectively varies the discharge area.