Innovative technologies for the economically sound identification and sorting of post-consumer textile-IDENTITEX
Preparation of textiles for the identification process Within this work package an appropriate separation process for post consumer textiles was developed. An analysis of technological influence parameters, as well as an analysis for the state of the art were executed and alternative technologies with different automation level suggested. Extensive investigations and tests were executed regarding adjustment parameters, configuration and dimensioning of the components and the entire module. Identification of textiles materials and colours based on NIR-/VIS-spectroscopy Within the IDENTITEX project a fully automated procedure for the online identification of material types and colours of textile materials was developed. Currently, a laboratory prototype is constructed and investigated at real textile streams. A main field of application will be the textile recycling sector. Here post consumer textiles have to be sorted into pure material and colour classes for an economical and environment compatible reuse. This automated system could replace the manual labour sorting that is very expensive, inaccurate, time consuming and loaded for the workers. A further potential application field will be the measurement of material characteristics for the quality control in textile production. It will be suitable e.g. by incoming inspection of raw textile materials or by the error detection at the end product. Thus, the production costs could be decreased considerably. The new procedure contains several innovative features, which are very promising for a successful market introduction: - Fully automated online identification of more than 10 textile pieces per second. - Adaptable to real textile streams e.g. on a conveyor belt, that renders a big range of applications even at existing production lines. - Combination of material and colour identification as well as the possibility to identify every important textile material type (e.g. cotton, wool, polyester, viscose, silk) and the complete colour range to realise extremely variable application possibilities. - A high identification precision of more than 90 % to get material fractions with high purities, which could be reused very efficiently. Sorting the identified textiles An automatic module is developed that is able to sort pieces of textile on the basis of the result of their prior identification. The end result should be that all, for example, cotton pieces are assembled in one bin with 95% accuracy. The system should also be modular to make sure that each future customer could sort textile pieces on its own specification and demand. The following was achieved: -A prototype is delivered with 1 conveyor belt. This conveyor belt is equipped with three sorting stations and one station for the unsorted fraction. -Knowledge of handling of textile pieces with undefined shapes and weight. Because each textile piece running over the �Identitex machine� has a different shape and position on the conveyor belt, a technique for handling / sorting these pieces was tested during various tests. -Communication protocol between identifying module and sorting module tested and proved useful. -The limits of the laboratory prototype were tested. The outcomes also apply for future production scale systems. For example, the laboratory prototype is built-up with conveyor belt systems. The practical maximum speed for conveyor belts are between 5 and 10 m/s. -Accuracy of the sorting part was tested and proved within limits. The integrated prototype of the automatic sorting machine An integrated prototype is developed that combines the three results mentioned before. Pieces of textile are put on a transport belt (e.g. from a bale) and the prototype automatically: - First separates the pieces from each other. - Identifies each piece. - Sorts the piece to the appropriate bunker on the basis of the result of the identification. The prototype has performed some 20 tests on the different materials. First tests were done with calibration material: 4 different types of fibres, polyester, cotton, wool and viscose. Later tests were done with post consumer waste. About 8 tons of this waste was tested in order to get a good mix of material and to be representative of the reality. Also the option to sort on the basis of different colours has been tested successfully. The prototype can work at speeds up to 4,4 m/s, which is the mechanical limit of the transport system employed. Speed increases should be possible from a technical point of view of the presorting-, identification- and sorting modules. Limiting factor is the proper running of the material: - The material should run smoothly over the identification sensor (not disturbed by e.g. an air lift). - The material should not fall out or stick on the belt (this is a missed item after which the system has to be reset). - The sorting should be performed with an air push system.