| 摘要 |
Particle separating apparatus includes a horizontally disposed rectangular screen or grid having openings adapted to pass smaller particles from a stream of particles of varying sizes while retaining larger particles upon the top of the screen. A conveying screw mounted in a trough below the screen conveys the smaller particles forwardly along the trough to a discharge opening. The screen is mounted above the screw for horizontal reciprocation along a path parallel to the longitudinal axis of the screw and is biassed by springs engaged between the front and rear ends of the screen and stationary surfaces to a normal rest position midway between the ends of the reciprocating path. A rigid drive member having a flight engaging roller or slide plate at its lower end projects downwardly from the screen into the path of the conveying flight of the screw and is driven forwardly by the screw flight as the screw is rotated until the front end edge of the flight rotates past the drive member to allow the screen to be driven rearwardly in a snap action by the springs engaged with the front end of the screen. The screen subsequently oscillates about its rest position under the action of the springs at the opposite ends of the screen to shake and sift smaller particles from the mass of particles collected at the top of the screen. Various arrangements for minimizing pinching of larger particles between the screw auger flight and the trough wall are disclosed.
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