The design of a yarn tension control system for the high speed formation of conical packages

The research described was primarily concerned with working towards the solution of the problem of yarn tension control when building conical packages on an open-end spinning machine at yarn delivery speeds of 500 m1min"cause of the total lack of published work on the mathematical modelling of the parameters affecting tension variation, a considerable amount of effort was spent in the establishment of this basic understanding. This mathematical analysis appears, in the main, in the appendices to this thesis. In addition to the analysis of yarn tension variations depending on machine geometry parameters, mathematical models have also been produced which predict the effect on tension of fitting curved distribution bars of various shapes. The work includes the development of concept ideas which appeared capable of providing routes for solution of the tension control problem. These ideas were evaluated and compared against a design specification which was also developed as part of this research. Two promising concepts were selected for detailed investigation. These were: a pneumatic passive compensator and, a positive mechanical compensator. The pneumatic compensator was a novel idea which was conceived by the author, and which eventually provided a solution which met the design specification in every way. The mechanical compensator was shown to be a far less attractive concept with several serious problems which have been explored but not eliminated. A preliminary investigation of a third concept involving microprocessor control was not sufficiently well developed at the time of publication to be included in this thesis.