| 摘要 |
<p>An element for use in forming a deck for a grading or dewatering screen is formed by casting an elastomeric material such as polyurethane into a mould so that a smooth sheet of the material is formed in a liquid state in the mould, lowering into the liquid elastomeric material a substantially rigid open-work reinforcement, such as a perforated metal plate, and an array of studs for forming apertures in the screen element, the studs extending through the openings of the reinforcement and through the elastomeric material substantially to the bottom of the mould, allowing the elastomeric material to set, and then withdrawing the studs from the set sheet of elastomeric material. This provides a screen element comprising a sheet of elastomeric material having a rigid reinforcement embedded therein and a plurality of grading or dewatering apertures extending through the elastomeric sheet, the apertures being aligned with the openings in the reinforcement. Preferably the reinforcement has projections, such as flanges, extending substantially perpendicularly from it and from the rear face of the elastomeric sheet on at least two opposite edges of the element.</p> |
