Patent attributes
An extruder with a housing comprising parallel, partially inter-engaging bores and screws disposed therein is used when applying a method of feeding powdery bulk materials into such an extruder. A solid transport of powdery bulk material takes place in an inlet zone disposed downstream of a feed opening wherein said inlet zone is partially filled. The inlet zone is provided with at least one gas-permeable wall portion wherein a layer of bulk material is created on said wall portion, thereby preventing bulk material from passing through, The gas-permeable wall portion is connected to a vacuum source and to a pressure gas source. Furthermore, the gas-permeable wall portion has an inner wall which is set back with respect to the wall of the bores, thereby forming a gap with a partially annular cross section wherein a layer of the bulk material is formed in the gap.
