fingings

Nowadays, air-jet weaving machines can weave almost all kinds of yarns without any problem at higher speeds compared to the projectile and rapier systems. This makes airjet looms a very good alternative to other weft insertion systems. However, this type of system still has a major drawback: the high power consumption due to the generation of compressed air. Therefore, intensive efforts have been made by researchers and air-jet loom makers to overcome this problem and achieve a dramatic reduction in air consumption without any decrease in loom performance and fabric quality.
Adanur and colleagues analyzed the air flow in the filling insertion process and investigated the effects of air and yarn characteristics . They reported that the propulsive force was largely independent of fiber material. They also explained the relation between yarn linear density and filling velocity. Mohamed and Salama studied the mechanics of the air-jet filling insertion and the nozzle design . Krause indicated that the linear density, structure and twist of a yarn were the main factors in the suitability of filling yarns for pneumatic insertion . Yarn velocity in the insertion channel increases as the number of filaments increases due to the larger yarn surface in contact with the air according to Kissling and Ishida . Many researchers have reported that open-end yarns gave higher mean yarn velocities compared with ring spun yarns because of the same reason . Poppe studied the air index and claimed that air consumption decreased as the yarn hairiness increased . No significant effect of twist direction on air-jet filling insertion was found by Wahhaud . Tarabadkar et al. indicated the importance of compressors on air consumption in spinning and weaving machines . On the other hand, some researchers studied the various loom parts such as the nozzle, reed, and valves to improve the filling insertion and reduce air consumption. For instance, Ishida and Okajima and Jeong et al. have developed an optimum main nozzle design.
Besides researchers, loom makers have been working to improve air-jet filling insertion. For example, the air-index concept was developed by Picanol as a measure of weft yarn suitability for air-jet weaving . The same company introduced a new relay nozzle design with 16 holes to reduce air consumption . Dornier developed a PIC (Permanent Insertion Control) system for permanent monitoring of the most important filling insertion elements . Similarly, Sultex claims outstanding results with regard to compressed air consumption on L5500 looms with the new AWC (Active Weft Control) system . Other loom makers also claim substantial reductions in air consumption following new developments in their designs .
However, the practical applications in weaving mills are as important as machine designs to achieve the claimed reductions in air consumption. This study aims to significantly reduce air consumption by optimizing some loom parameters in a weaving mill. It is mainly focused on relay nozzles due to the fact that 80% of compressed air is consumed by these nozzles . This study also involves the effect of selvedge pattern, which is created by a pneumatic tuck-in device, on air consumption.