Abstract
A fibre shortener comprises at least two extrusion screws (1,2) having each: a rotational axis for rotation in a positive direction (8), at least two transport sections provided with transporting screw threads (15) of positive pitch; and at least one reversed screw section provided with a reversed screw thread (16) of negative pitch and being arranged between said transport sections; the extrusion screws being arranged in parallel relation for intermeshing corotation: and each reversed screw thread being provided with at least one window (10) providing a passage through the respective reversed screw thread. In the reference plane defined by the respective reversed screw thread, each window has an essentially rectangular cross section. The width of the cross section of each window is chosen in dependency of the desired fibre length of fibres to be obtained, wherein said width decreases if the desired fibre length decreases.
| Original language | English |
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| Patent number | EP0979895 |
| Publication status | Published - 2000 |