| 摘要 |
<p>In a fiberising device according to the nozzle blasting principle, the blasting nozzle (6) is followed on the downstream side by a subsonic diffusor (11) which is constructed as a pulse diffusor whose flow cross-section shows abrupt widening to form individual steps (13, 14, 15). This makes it possible to employ an average aperture angle ( alpha ) which is significantly greater than in subsonic diffusors with continuous flow confinement without harmful detachment of the main flow. Furthermore, the vortices which form underneath the cut-back areas prevent direct contact of the filament constituents with the wall, and this, together with the pronounced flow expansion and hence reduction in mutual contact and penetration of filament constituents, results in an appreciably reduced bead content. The diameter distribution of the fibres is uniformised, since, as a result of the energy consumption by the vortices, the strongly edge-accentuated velocity distribution coming from the slot (8) is more rapidly uniformised. By systematically introducing further blasting medium in the area of the subsonic diffusor (11) it is possible to influence the flow systematically in order to meet all fibre quality requirements. …<IMAGE>… </p> |
