Natural frequency vibrating screen

Abstract

A horizontal vibrating multi-deck screen apparatus for separating different sizes of materials of generally the same type. The apparatus includes a first or upper screening basket and a second or lower screening basket. The upper screening basket has a feed chute at one end and a discharge chute at the opposite end. Each screening basket has at least one screen deck thereon for conveying and screening material. The two baskets are connected by a spring-type coupling system, including coil springs and fiberglass leaf springs. The two baskets together are supported by known types of support spring systems installed between the upper basket only and a base frame. Hence each basket constitutes one mass and each spring system one spring of a two-mass two-spring system. A pair of shaker motors mounted directly, one on each side, on the lower basket inputs a straight-line sinusoidal exciting force to the system. The exciting force and the spring forces are transmitted to both baskets and induce vibrations. By adjusting and controlling the masses of the baskets, the spring rates of the two spring systems and the magnitude of the exciting force, the desired vibrations will be achieved, with the operating frequency maintained near but below the upper natural frequency of the apparatus.