| 摘要 |
At the upstream end of the nozzle body (1) between each pair of adjacent inlet openings (3) a partition (5) runs parallel to the axial direction of flow (F). On its (5) upstream end there is a cutting edge (5a). Upstream of the inlet region (2a), each adjacent inlet opening is fully-surrounded by partition walls with upstream cutting edges. The cutting edges include an angle other than 90[deg] with the flow direction. The outlet section (2c) widens along the flow direction, over the outlet length (LA). Its angle increases along the length, the rate of increase itself being proportional to the length. A bell-shaped contour results, flaring to an angle of 90[deg] with the flow direction, at the outlet end (4). The widening may follow a circular cross section, whose radius of curvature (RA) exceeds the radius of curvature of the channel (RK). A length (LR) of the outlet region is surface-roughened. The nozzle opening configuration is further detailed. Its channel cross section is circular. The axial length of its inlet region (LE) is 50%-80% of the total nozzle channel length. The flow velocity of the viscous mass along the inner region of the nozzle channel (VF), exceeds LR/TRELAX, where TRELAX is the relaxation time of the viscoelastic mass and LR is the axial length of the roughened region. An independent claim is included for the method of strand extrusion, particularly of a polymer or dough. |
