Yarn Posture in an Air Suction Gun

Abstract

The geometrical effects of an air suction gun on yarn motion were clarified by measuring postures of a running yarn with a still camera in order to promote the suction performance by controlling the yarn motion appropriately. The relation between the yarn posture and yarn suction force was also discussed. The yarn posture is a helix. This helical motion greatly improves the suction efficiency of the air suction gun owing to high concentration of air drag on the yarn. Helix diameter of yarn posture dy and helix pitch of yarn posture py decrease with an increase in the compressed-air inflow angle and a decrease in the throat diameter of de Laval tube, and are almost independent of the passage diverging angle of nozzle and the converging angle of de Laval tube. Unfavorable values of the geometrical parameters cause large fluctuations in yarn postures, i.e. violent yarn motion. A stable yarn posture with appropriately small dy decreases the friction between the yarn and the wall of tube, and an appropriately small py increases the contact area between the yarn and the air. Hence the yarn suction force is promoted.

Yarn Motion in an Air Suction Gun

“…Further analysis of the relationship between the yarn motion in the present study and the yarn posture in the previous paper [5] confirms that an increase in vyc is accompanied by decreases in the helix pitch and diameter of the yarn posture in general.…”

“…4 we can see that the motion path of a yarn segment is different from the yarn posture presented in the previous study [5]. Figure 9 shows the effect of compressed-air inflow angle φ on the yarn motion in the region A, which is in the middle of the de Laval tube, and the region C, which is in the middle of the straight tube.…”

“…The record rate was set at 16000 fps. A detailed description of the measurement method for determining the yarn position was given in the previous paper [5].…”

“…Details of the photographing device and method have been given in the previous paper [5], and therefore are omitted here except that a high-speed video camera was used in place of a still camera. This method was used to investigate yarn posture and motion in an interlacer in interlacing process [6,7].…”

“…As a fundamental experiment for analysis of the yarn behavior, we have investigated yarn posture by analyzing photographs of a running yarn taken with a still camera, and clarified the geometrical effects on the yarn posture [5]. Here, the yarn posture means a shape of yarn centerline in the gun.…”