Study on Interlaced Yarn

Abstract

The flow field in a yarn path is clarified by measuring pressure distributions at the surface of a yarn duct and flow velocity distributions near the surface of a yarn duct of an interlacer. An interlacer enlarged similarly to a real interlacer has been manufactured on the basis that the flow fields in two similar interlacers in geometry are also similar in dynamics. In this manner detailed measurements can be made and data with high accuracy can be obtained. Results are as follows.(1) With regard to the axial direction of the yarn duct, the pressure hs takes a maximum value in the neighborhood of Z=0 and a minimum in the neighborhood of |Z| =1, where Z is the axial distance from the center of the air jet nozzle non-dimensionalyzed by the diameter of the yarn path.The value of hs gradually increases with |Z|, and is identical with the atomospheric pressure at |Z| = 2. The above-mentioned tendency is independent of θ and p in the present experiment, where θ is the circumferential angle in the yarn duct from the center of the air jet nozzle and p is the air pressure in a rectification tank.(2) The variation of hs with respect to θ depends upon Z. In Z=0 the value of hs is extremely large at θ=180° and reaches a minimum in the vicinity of θ =90, 270°. In Z=1 it shows a considerably small variation, and a minus value in many regions. In Z=2 it is almost constant and nearly equal to the atomospheric pressure.(3) Comparing with p, the value of hs is almost equal to the atomospheric pressure in many parts of the surface of the yarn duct.(4) The air jetting from the air jet nozzle radially spreads after running against the wall opposite to the air jet nozzle. The air with a circumferential component of flow velocity flows along the curved wall, and two eddies which are symmetric with respect to the plane through θ =0 and 180° and rotate in opposite directions to each other are formed. With increasing |Z|, the circumferential component of flow velocity reduces and the axial component is dominant. The main flow moves from the periphery of the yarn path to its center.With regard to the circumferential direction of the yarn path, the flow is biased toward the semicircular region nearer to θ =180°.(5) The present experiment shows that the air flow pattern in a yarn path is independent of p.(6) It is considered, that the air jet causes opening and tangling actions of a yarn at the region (|Z|<1/2) where the jet directly runs against a yarn, and a yarn motion similar to a rotation at the region (|Z|<1) where the circumferential component of flow velocity is relatively dominant. (7) The influence of errors in manufacturing interlacers appears noticeably in the flow field in a yarn path.These errors are considered to cause various characteristics to yarns even when the processing conditions are the same in every interlacer.