| 摘要 |
Granules, especially of rigid polystyrene foam, with a wide particle size distribution are classified in a sieving plant (2) fitted with a rotary sieve (4,5,6) with graded hole sizes (14,15,16) contained in a housing (27). Within the sieve (4,5,6) are swirl and/or impact bodies (7,8,9,10,11,12) which act with a radial alternating air stream to mix, crumple and classify the particles (53). Below the sieve is at least one exit opening (28,29,30) for the granules (54,55,56). Oversize particles remain exposed to the compressing and crumpling effect till they pass the sieve. Preferably the particles (53) are fed through a central inlet (13). Unclassified material can be drawn off through a final opening (23). Connections are provided in the housing (27) to produce an alternating or pulsating radial stream of air across the sieves (4,5,6) which produces a sieving action and prevents clogging. The swirl bodies are inclined rods running along the inner surface of the sieves (4,5,6). Sieved material is removed through funnel shaped exit openings (28,29,30) by pneumatic action. The sieve shaft (3) is rotated intermittently by a controller to give several oscillations of 300 to 345 deg followed by one or more complete rotations. External brushes are fitted to release clogged sieve holes. Air connection hoods and sieve mountings are fitted with quick release couplings to assist cleaning.
|
