6. Outlook

Even though the performance of the cleaning systems in the preparation line will eventually be improved, it has to be admitted that they can offer only a relatively coarse filter. Its efficiency is only satisfactory if the claims with respect to quality are limited or if a clean raw material can be used. In the case of high demands or if the raw material is highly contaminated additional filters will be necessary. Very often yarn clearers are installed on automatic winders or open end spinning machines. These devices have the task of a fine filter at the end of the production process. Coloured and now apparently colourless foreign fibres are detected.

Picture 6: Cleaning of contamination by 3 filters

Yarn clearers, however, make only sense if the frequency of impurities is low; otherwise the number of necessary cleaning operations would rise to a level which cannot be economically justified any more. Here the essential difference of a measure in the opening room compared to a yarn clearer becomes evident.

The yarn clearer cuts the yarn and splices it afterwards always causing production interruption and loss in quality while there is no production interruption with a machine in the opening room. In these circumstances the use of a cleaning device in the preparation as well as a clearer at the end of the process has become a world standard. However, it is still not sufficient in case of most serious contamination. In such cases it should be checked whether an additional in this case even coarser filter should be installed at the beginning of the preparation. It would guarantee that the number of Contaminations which subsequently gets to the fine opener will not exceed the limit of 700 pieces per hour. In this case the cleaning device at the end of the preparation line would be effective enough and the electronic clearer could perform as the final filter without sacrificing too much loss of machine efficiency and yarn quality.

Picture 7: SORTER HP

High Production SORTER (up to 1200 kg/h) including optical and acoustic sensors, offered by Loptex for installation at the beginning of the preparation line, after first opening.