Developing systems for the removal of impurities seen in the first stages of the cotton cleaning and yarn production, USTER® Jossi Systems introduced three new methods based on physical effects for the removal of plastic impurities in cotton, which is one of the most common problems experienced by the spinners. Since white polypropylene (PP) is used as packaging material for cotton bales and fertilizer bags used in cotton fields, the scraps of white PP mix with cotton and reduce the quality of the cotton. The optical systems designed for separating the PP from cotton did not meet the expectations.
Detection via UV Light
Developing the detection system called VTECT on the basis of the principle of using UV light to detect materials containing brightener, USTER® Jossi Systems offers high detection efficiency for all kinds of materials treated with brightener with a system beyond the ordinary systems. Offering a basic level of protection against white PP, this system may need other detection principles for a full solution since the white PP with brightener can be a relatively small part of the contamination.
Detection through the Use of Scattering Effect
While the light falling on the cotton turfs forms a wide halo, the light falling on plastic creates a small reflection with sharp edges. Due to the scattering effect, the differences in the reflections can be detected by analyzing images rather than single pixels. This allows for detecting and removing PP particles. This effect is equally successful in the detection of both white and coloured PP.
Detection by Using MagicEye
For best removal of the foreign matters from the cotton tufts, the ideal solution is combining the optional MagicEye and VISION SHIELD XSPECT T. Having a high detection capacity for plastic foreign matters, MagicEYE scans the cotton tufts and can control the physical properties of the scanned materials completely. Since materials are identified on the basis of their characteristic spectroscopic properties, MagicEye stands out as the most reliable method.
Although MagicEye has the best detection rate for white PP, it has some limits related to the size, orientation and presentation of the foreign matters. Looking through the material flow with the combination of these three different systems developed by USTER® Jossi Systems leads to more effective results in the subsequent cleaning processes.
