Feeder tube for bulk product

Feeder tube for bulk product, wherein said feeder tube is designed for feeding bulk products of wood chips, and/or fibrous material and/or powder where bridging can easily arise, which feeder comprises a cylindrical drum or tube (2) in which there are accommodated a large number of inlet openings (8) distributed along the length of the tube, a screw conveyer (3) disposed coxially within the tube (2), a first arrangement for rotating the tube about its axis, a second arrangement for rotating the screw conveyer (3) relative to the tube (2), a third arrangement for moving the feeder tube (1) in the lateral direction, and activators (9A, 9B) for the bulk product, which activators form projections on the outer side of the tube (2) and are disposed on the tube in association with said inlet openings (8), wherein each cross section along at least 40% of the length of the tube (2), there are disposed at least two inlet openings (8), characterized in that openings (8), activators (9A,9B) and the rotational speed of the tube (2) are arranged to facilitate a lateral velocity of the feeder tube within a pile of bulk to substantially exceed 30 mm/min, wherein the rotational speed of the tube (2) is 0,5-15 rpm, at least two actively positioned activators (9A, 9B) are also positioned in each cross section and that for a feeder tube (1) having a desired average volumetric capacity (V′) the slot width (d) of the majority of the openings (8) is chosen by means of V′˜dn, wherein n is between 2-3 depending on bulk material, in combination with that in a portion comprising at least 30% of the length of the tube (2) the total sum of the width (Σd) of all openings (8) in each cross-section is between 150-700 mm.