PURPOSE: To effectively utilize a space in a drum by providing an inclined screen, a pan, an ultrasonic probe, a buffering chamber, a rocking trough and a means for feeding into a storage facility, for adjusting a ratio between an attachment and a hull.

CONSTITUTION: An inclined screen 12 comprises a parallel array comprising a plurality of bars 14. An attachment 20 has a size of mutual interval of a bar 14, to be dropped into an inclination-allowed trough 26. A deflecting shoot 28 guides the attachment 20 as far as an inclination-allowed trough 30. Then it is released into a transmission chute 32, and then into a drum 34. A hull 22 falls from between the bars 14 into a hopper 40. Then, it is discharged through a maintenance cut-off valve 41 in a discharge chute 44. An ultrasonic wave probes 54a and 54b detects filling level of the attachment 20 and the hull 22 within the dram 34. A capacitance probe 56 monitors the drum 34 for excessive filling. Ultrasonic probes 58a and 58b monitor filling level of the hull 22.