A number of data collection devices are free to move relative to each other through their environment, collecting data from their environment. The soil jam preventing structure includes a sump case mounted on a floor of the tub to reserve washing water and a sump cover seating on an upper portion of the sump case, the sump cover having an outer frame portion, a rib extending from the outer frame portion, and a foreign object drain groove formed by cutting away a portion of the rib. The disclosure moreover also relates to a method for operating such a packaging machine.