Journal of the Textile Machinery Society of Japan

Analysis of Yarn Tension in Air-jet Nozzles

Nobuo Iwak, Toshiyasu Kinari, Hiroyuki Yamazaki

1991 Volume 37 Issue 2 Pages 35-40
Published: 1991
Released on J-STAGE: October 24, 2006

DOIhttps://doi.org/10.4188/jte1955.37.35

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In the insertion of yarns by air-jet, the yarn acceleration in the jet nozzle is one of the important factors. The present investigation is planned to discuss the yarn tension mechanism in nozzles as follows.
1) Air flow rate and its velocity in nozzles are measured experimentally.
2) The drag force acting on different kinds of yarns according to yarn structure and count is measured. The yarn tension obtained is compared with the theoretical value calculated from the drag coefficient based on the Reynolds number.
The results obtained were as follows.
1) An increase of the bore size of the induction nozzle provided in the jet nozzle increases the air flow rate inducted by driving flow. The maximum bore size was 3mm.
2) The induced flow rate reached a limited value in spite of increasing the driving pressure.
3) The applied tension on the yarn in a jet reached a limited value in spite of increasing the length of the acceleration pipe.
4) The yarn tension calculated from equations based on the isentropic flow of compressible fluid and the air drag in the nozzle were in agreement with those obtained experimentally.

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Development of a New Evaluation System of Frictional Static Charge

Part 2: Dependence of Electro-Static Properties of Various Fibers upon Temperature and Humidity

Masao Matsui, Kazuo Okamoto, Takamitsu Kashiwamura

1991 Volume 37 Issue 2 Pages 41-48
Published: 1991
Released on J-STAGE: October 24, 2006

DOIhttps://doi.org/10.4188/jte1955.37.41

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In part 1^[1], the reproducibility and accuracy of newly developed KB system were compared with those of Rotary Static Tester (RST) and Faraday's Cage Method in JIS L 1094 (1980). It was proven that the KB system has a higher reproducibility and a higher accuracy than these existing measuring methods.
The temperature and humidity dependence of frictional charge and it's decay rate of various kinds of fabrics, which are composed of natural fibers, antistatic synthetic fibers and non-antistatic synthetic fibers, has been investigated by the KB system. It has been found that the static properties of the fibers change remarkably at the relative humidity of 40% to 60%, and any significant difference of static properties of the fibers is not seen between 20°C and 25°C of measuring temperature. It was concluded that the optimum temperature and humidity to measure the static or antistatic properties are 25°C and 30%RH to 35%RH from the view point of accuracy, stability and practical measurement.

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Development of Check up System for Picking Mechanism on Water Jet Looms

Kazuhide Chikaoka, Ryuji Shintani, Toshiyasu Kinari

1991 Volume 37 Issue 2 Pages 49-57
Published: 1991
Released on J-STAGE: October 24, 2006

DOIhttps://doi.org/10.4188/jte1955.37.49

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A check up system for picking mechanism on water jet looms is developed. This system catches the signal of water jet pressure with a pressure sensor, and detects the open-close of a clamper with a clamper sensor respectively, and measures such values as water jet pressure, jetting angle and flight start angle of weft yarn etc. As these measured results, this system can find the best condition of picking mechanism for weaving.
This system is available for preventive maintenance of picking mechanism, and contributes to decrease loom stoppage and poor condition of weft flying resulting in improvement of flexible manufacturing.

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