thread 14 1 14 2 and 14 3 by means of a preparation device 15 the threads 14 1 14 2 and 14 3 are combined in parallel in a plurality of treatment stages and are crimped into a bcf yarn 21 by means of a crimping device 19 the treatment stages in this case contain a pretangling device 17 for the separate pretangling of the threads 14 1 to 14 3 and a take up device 18 for taking up and drafting the threads the crimping device 19 is in this case designed as a compressive crimping device by means of which the threads 14 1 to 14 3 are textured into a thread plug the thread plug is subsequently cooled via a cooling drum 20 and taken up to form the bcf yarn 21 before winding by means of the winding device 23 a secondary swirling takes place by means of the secondary swirling device 22 the bcf yarn 21 is wound into a bobbin 8 in the winding device the bobbin 8 is assigned an image acquisition appliance 3 by means of which an image of an extract of the bobbin 8 is detected the image acquisition appliance 3 is coupled to an image analysis device 4 by means of which the data of the image are analyzed and extracted an analysis is carried out from the extracted computation data by means of the evaluation device 5 the evaluation device 5 is coupled to a control device 7 which controls the entire bcf spinning process in the exemplary embodiment illustrated in fig6 of the apparatus for producing a bcf yarn different method variants can be.