Improvement On Closing Fibers-converging Device Of Swirl Spinning And Yarn Performance

Swirl Spinning is a new spinning method which is based on the traditional air-jet spinning while has overcome some of its shortcomings. The Fibers Converging Device (FCD) is the key part of Swirl Spinning, whose gathering quality can effect yarn quality. Closed Fibers Converging Device (CFCD) that is a new fiber converging could converge fibers effectively; however, it twists the fibers to yarns when peeling off at the same time, the yarn performance thus is poor and it won't be able to form yarns continuously.The article is aimed to solve the problem that CFCD faces when twisting directly after peeling off. Based on the traditional CFCD, a new FCD is designed with a yarn-guiding tube and a pair of yarn-guiding rollers. The fibers could be peeled off from the Converging Device continuously by the rollers, then be twisted to yarns by the use of a swirl twister. In the article, a new spinning method which allows peeling off first and then twisting is introduced; the influences on yarn performance because of the spinning machine's improved performance and its technological parameters by the application of the developed CFCD are analyzed; also clarified by numerical simulation is the twisting principle of the swirl twister. The main contents could be divided into the following four parts:(1) Updating the traditional CFCD. Based on the quantities of experiments done ahead of time, a new converging device with a yarn-guiding tube and a pair of guiding rollers is designed and a flow of spinning process introduced. Meanwhile, the newly designed device was manufactured and installed on a spinning machine; after debugging, it proved that continuous spinning could be realized.(2) Analyzing the yarn performance on a spinning machine who applied with the newly designed Converging Device. Compared to the yarns spun with the traditional converging device, under the same optimal technical parameters, the yarns spun with the new device perform better.(3) Analyzing the influences of the main technical parameters on the yarn performance after the improvement of the converging device. From the experiments, it found that the nozzle pressure and the rotating speed of the converging device are the key influential factors to the yarn performance. By studying these two factors respectively, it shows: for nozzle pressure, the yarn performance is much better when the swirl twister,s P1 is 0.1 MPa and P2 is 0.3 MPa; and for the rotating speed of the converging device, it's much better when it's 30000 r/min.(4) Analyzing the twisting principle of the swirl twister. A swirl twister is made of two similar nozzles; by studying the air flow of the first nozzle could help understand the principle. Conclusions are: Firstly, after the improvement of the converging device, it is the radial velocity of the air flow from the first nozzle that produces the tip free fibers, the tangential velocity of the air flow that realizes wrapping and tangling, and the axial velocity of the air flow that helps the fibers into the swirl twister. Secondly, the fact that the nozzle's intake air speed variance has an influence on the internal air flow proves that the twisting pressure could influence the yarn performance. Thirdly, the twisting principle of the swirl twister is to produce a quantity of side fibers and then wrap and tangle firmly to the core.The above conclusions could be referred as an experimental and theoretical basis for the further development of the swirl spinning machines.