SCREEN FOR SEPARATING AND CLASSIFYING PARTICULATE MATERIAL AND METHOD OF MAKING SAME

摘要

A screeen (21) for separating and classifying smaller particles from larger particles of a particulate substance wherein the screen (21) is of a planar configuration and made from a slab of synthetic material. The screen (21) includes a plurality of spaced perforations (23) formed by cutting the slab with a pressurized stream of fluid, which method of forming produces perforations (23) of highly uniform configuration and dimensions, particularly when the slab is a composite comprising plural layers of different synthetic materials. The perforations (23) are configured to compensate for foreshortening of their top openings (27) and accelerated wear tendencies during use of the screen (21) in an inclined disposition.