US 2008/0110806 A1 · Process And Device For Separating Plastics Of Different Chemical Composition By Flotation

Abstract

This invention comprises a method and a device for separating plastic materials in accordance with their chemical composition. That is based on the difference in density of such materials, since each individual plastic material possesses a density, which is unique for such individual plastic material and reflects its chemical nature. Pure plastic material obtained by this invention may then be returned to a material specific re-usage. For this purpose a flotation process has been developed which works with a flotation liquid that is put into vibration, the frequency of that is controlled in accordance of the density of the particles to settle. Heavier plastic particles settle on a perforated plate bottom and are removed to a collecting container filled with the same liquid to the same level as the flotation tank. Lighter plastic particles float to the surface and are fed into a follow-up flotation tank for further separation.

Claims10

Dependent claims

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;
and
wherein equality of the thickness (D) of the sediment layer on the perforated plate bottom is regulated by at least one control device that effects on swiveling flaps pivoted underneath the perforated plate bottom and which receives commands by sensors which measure the thickness of the sediment.

2 more elements

Separation device for separating plastic materials of different chemical composition, comprising:

a flotation tank filled with flotation liquid that is loaded, without creating whirls in the flotation liquid, by a filling tube with a conglomerate of plastic particles of various chemical composition pre-prepared in a shredder and comprising a device for producing a pulsation, which provides intermitting propulsion impulses;
a vibration distributor located in the flotation liquid underneath of a perforated plate bottom that separates the flotation liquid;
a continuously operating discharging device which scratches settled plastic particles and removes them into a collection container that contains liquid to the same level as the flotation tank;
a conveyer to transport the settled plastic particles into a checking containment;
and
swiveling flaps pivoted to the lower side of the perforated plate bottom that effect an equalizing of the surface and the thickness (D) of the sediment layer on the perforated plate bottom and which are controlled by a controlling device that receives its commands from sensors.

3 more elements

Dependencies are inferred from the claim text.

Process And Device For Separating Plastics Of Different Chemical Composition By Flotation

Life of this patent

Process And Device For Separating Plastics Of Different Chemical Composition By Flotation

Life of this patent

Abstract

Claims10