| 摘要 |
This invention concerns an arrangement for separating plastics and other materials of different densities in a liquid bath by flotation. The batches of plastics fed to the flotation baths often also contain ferrous metals and non-ferrous metals and other materials which are heavier than plastics. Since these materials in the batch which is to be separated are heavier than plastics, they settle quickly on the perforated base (1) while the plastics particles are still floating in the flotation bath. The still-floating plastics particles are transferred to a second stage and separated there in accordance with their different densities. The heavier materials, which settle from the batch in the first stage, easily result in the through-openings for liquid in the perforated base (1) closing. For this reason, it is the problem of this invention to remove these materials, usually settling on the perforated base in pile form, again without causing the liquid settled in the settling tank (27) to move in an undesirable manner, and thus to prevent already settled materials from rising up and mixing again with still-floating plastics particles. The invention proposes to mount the perforated base (1) in a movable manner, to leave a gap between the perforated-base boundary and the wall of the settling tank and to displace the perforated base (1) at intervals slowly in a direction which reduces the size of the gap and quickly and abruptly in the opposite direction: as a result of the abrupt movement of the perforated base (1), the kinetic energy stored in the piles of metal or the other heavy materials moves these materials in the direction of the gap periphery (S) and conveys them through the gap (7) into the settling chamber located beneath the perforated base. These materials can then easily be guided away from there. |
