Air flow through a weft passage of profile reed in air jet looms

摘要

An air jet loom equipped with a profile reed and sub-nozzles is able to weave wider fabrics at higher speed than other types. A study on the characteristics of airflow and behavior of the weft yam in the well passage area of the profile reed during inserting the weft yarn is very important. The velocity distributions of airflow issued from a sub-nozzle in the weft passage were measured in detail by a hot-wire anemometer. The motion of a weft yam in the weft passage was also observed by photography. The experimental results indicate that the shape of the lower jaw part of the profile reed affects positions of the maximum velocity of the air jet in a cross-section until the air jet runs into the bottom of the reed. When the front side of the profile reed is closed, the value of the maximum velocity in the weft passage is smaller than that under the normal condition because of increasing of flow leakage behind the profile reed. The position of the maximum velocity in the weft passage is found to coincide with the position of the maximum leakage from the profile reed. It is confirmed by photograph that a yarn tip is led through the weft passage by the jet issued from a sub-nozzle.