Picking nozzle of air jet loom and pipe used therefor

Abstract

A pipe for use in a weft inserting nozzle of an air jet loom has a tapered portion which is formed inside the pipe so as to have a shape which is gradually and continuously enlarged in the direction toward the outlet side of a fluid, thereby the flow speed of the fluid on the out let side of the fluid being made larger than that on the inlet side of the fluid, and the pipe has a length of 150 mm or less. The inside of the tapered portion has a shape of which the sectional area or the diameter is gradually and continuously increased as advancing toward the outlet side of the fluid. The tapered portion has a diameter of 3 mm or more on the inlet side of the fluid and a diameter of 5 mm or less on the outlet side of the fluid. The inclination angle of the tapered portion is 0 DEG or more but is 1 DEG or less.

Description

technical field [0001] The present invention relates to a weft insertion nozzle (main nozzle) of an air-jet loom that uses air as a fluid for weft insertion. Background technique [0002] As a kind of weft insertion nozzle of air-jet loom, just as the technology described in Japanese Patent Publication No. 2-42930 (page 2, Fig. 1, Fig. 4), in this prior art, It includes: a weft yarn guide with a through hole for inserting the weft yarn; a body configured to surround the through hole and constitute a fluid flow path; The rectification hole is formed by a pipe such as a pipe. The cross-sectional area of ​​the rectification hole increases stepwise towards the position of the fluid outlet, and has a stepped cross-sectional shape. [0003] The weft yarn that has passed through the through hole stands by in the state exposed from the front end (fluid outlet) of the rectification hole. When weft is inserted, the pressure fluid is sprayed into the r...

AI Technical Summary

Problems solved by technology

[0005] However, in the above-mentioned prior art, at the start of weft insertion, the weft front end in the weft insertion nozzle flutters in the rectification hole at the start of weft insertion because the weft front end that is stationary in the rectification hole is rapidly accelerated from a stationary state. If it is damaged, weft knuckles and kinks are prone to weft knuckles and kinks on the reverse feeder side of the weaving fabric after weft picking.

[0006] In addition, since the section of the rectifying hole is gradually increasing in a step shape, near the sharply increasing portion of the boundary of the portion whose inner diameter increases in a step shape, the vortex is likely to be caused due to the detachment of the pressure fluid flow.

At this time, the flow loss of the pressure fluid caused by those vortices increases, so that the conveying force (the force of the fluid to convey the weft yarn in the weft insertion nozzle) decreases

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