| 摘要 |
<p>A screen for a sieve for sifting particles of a predetermined size from a loose ore conglomerate has an upper layer of longitudinal straight strands each comprising glass fibre core covered by an abrasion-resisting organic elastomer and having a circular cross-section, the strands being parallel to and spaced from each other in a first plane and a lower layer of similar straight spaced parallel strands perpendicular to the strands of the upper layer and contacting the latter at crossing points. The elastomer surfaces of the strands of both layers are secured together at the crossing points by the strands having been heated sufficiently to produce a predetermined degree of melting of the surfaces and thereafter pressed, thereby to fix the crossing strands permanently relative to each other to define mesh openings of predetermined configurations and dimensions the screen having a space ratio of at least 60%, and the strands of the lower layer being tensioned. The use of glass fibre cores counteracts the generation of low frequency noise when the screen is in use and makes the screen light and flexible.</p> |
