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SHARP EYE separates single-layer PET trays from PET bottles

New technology application with higher light intensity

31 August 2018

A new application of TOMRA’s sorting technology, TOMRA SHARP EYE, has made it possible to separate single-layer PET trays from PET bottles. This breakthrough, which enhances the previous capability of TOMRA’s AUTOSORT machine to separate multi-layer trays, is important: small but critical differences in the chemical properties of PET food trays and PET bottles mean that they have to be separated for equivalent-product recycling.

The key to this innovation is an enhancement of TOMRA’s FLYING BEAM®, which was already the best sensor technology available. As the first near-infrared (NIR) scan system with point-scanning (and no need for external lamps), this focuses only on the area of the conveyor belt being scanned. Allowing a wide range of calibration possibilities, this can distinguish even the finest molecular differences in materials flowing down the recycling line – and now that TOMRA SHARP EYE introduces a bigger lens for higher light intensity, it is possible to detect even the properties that are most difficult to distinguish.

The step-by-step process which concludes with the separation of single-layer PET trays and PET bottles is seamless and flexible. During the preparation for sorting mixed plastics into different polymers, packaging material collected or pre-sorted from municipal solid waste (MSW) first runs through a mechanical treatment process which reduces voluminous materials, mainly soft items such as plastic, film, and non-plastic products. To then separate mixed PET into different polymers,
TOMRA’s AUTOSORT machine functions as a combined system, detecting material and colour in combination with grain size. Even with a very mixed material input, this process achieves an impressive sorting efficiency of 95% or greater.