Designs Of Nozzles And Researches Of Process On Air-jet Spinning

Air-jet spinning is a new spinning method, which utilizes two sections contrary high speed airflow produced by two nozzles to finish false twisting and wrapping. In comparison with traditional spinning technique, air-jet spinning is provided with many advantages, such as high output, short technologic process and extensive spinning area. It has aroused more and more people's attention, and it is developing in a high speed in these years. Owing to the limit of spinning principle, air-jet spinning produces a wrapping yarn, which is formed by outer fiber wrapping inner fiber. So there is no genuine twist on the yarn, and the yarn strength is lower than that of ring spinning yarn, T/C air-jet yarn strength is less than 90% of that spun by ring spinning, 100% cotton air-jet yarn strength is less than 70% of that spun by ring spinning.Now, the number of air-jet machines in our country has achieved to 200, which only attains 0.4% spinning ability, and the development is dramatically behind of America and other countries of Asian. Besides the marketing factors of the air jet spinning, one important reason is the extremely high price of the import air jet machines. Therefore, the nozzles of air-jet spinning machine having automatic intellectual property is developed by this thesis, which reduces the price of the machines, meanwhile, the structure parameters of nozzles and the parameters of spinning process are researched and designed, with which the strength of air jet yarn may be improved.This paper mainly includes three parts. In the first part, the development of air-jet spinning, the research actuality, the aim of this thesis and the research content are introduced. In the second part, the theory of air-jet spinning technology is discussed, and the approach of improving air-jet yarn's strength is given, which is increasing the number of the wrapping fiber and the degree of the wrapping compactness. In the third part, the structure parameters of two nozzles and the parameters of spinning process are analyzed and designed, some of mathematical methods are used to analyze the influence of different parameters, and adopts the rotary experimental design to obtain the relation between these parameters and air-jet yarn strength. On the base of mathematical model, the parameters are optimized, the strength of air-jet yarn is dramatically improved.From this paper we can draw the following conclusions, the strength of 100% T air-jet yarn attains 168% of that national criterion spun by ring spinning and 91% of that Uster criterion spun by ring spinning, and T/C air-jet yarn strength attains 148% of that national criterion spun by ring spinning and 88% of that Uster criterion spun by ring spinning, and 100% cotton air-jet yarn strength attains 95% of that national criterion spun by ring spinning and 71% of that Uster criterion spun by ring spinning. The air-jet yarn strength of these three kinds material has attained the anticipatory aim.