Patent ID: 7950525

Claim:
A method for separating plastic materials of different chemical composition by a flotation process, comprising the steps of: feeding shredded plastic materials into a flotation tank filled with water where the materials sink down slower or faster depending on their density; vibrating the water in the flotation tank to prevent lighter plastic particles from sinking down and to make the lighter plastic particles float upward to the surface of the water and into a container, and to cause heavier plastic particles to sink down and settle on a perforated plate bottom in the flotation tank forming a sediment which is extracted by a discharging device into a collection container; transporting the plastic particles collected in the collection container by a conveyer into a checking containment for a quality check; measuring the thickness of the sediment using at least one sensor; and regulating the thickness of the sediment layer on the perforated plate bottom using at least one control device that controls swiveling flaps underneath the perforated plate bottom and which receives commands from the at least one sensor.