Yarn Tensioning Device
Some tension is already generated during over and unwinding. this tension is inadequate. Is become necessary to employ a yarn tension device that rise mean thread tension to required level.Principle of Tensioner
- By applying frictional retreading force
- By passing through surface’s
Tensioning device applying frictional retarding force work on any one of the following two principle or their combination.
- Multiplicative type tensioner
- Additive type tensioner
Multiplicative Type Tensioner
These
yarn tensioner work on the principle of frication crated by envelopment of
running yarn around a surface. Let a running yarn be enveloped round a surface,
let T1 and T2 be incoming and outgoing tension
respectively and “ϴ” be the angle of envelope then outgoing tension T2 is given by,
As output tension is obtained by multiplying input tension by factor “eμϴ”, that know as multiplicative type tensioner.
Gate Type Tensioner
- Consist of two gate with polished steel rod or porcelain tube, one gat is fixed and other is movable.
- Output tension,
- The required tension can be get by setting of envelope, and that is done by screw.
- More is the penetration, greater would be the angle of lap there by greater wound be the tension applied by tensioner & vice versa
Additive Type Tensioner
In additive type of tensioner, yarn passes between
two surfaces which are pressed again each other.
Let R normal relation and μ the coefficient of friction between yarn & surface. Each surface
applies frictional retarding force equal to μR (for one surface) but here two surface so “2μR”,
T2 = T1 + 2μR
Incase 2μR is added to input tension T1
to set output tension T2 that called additive type tensioner.
Disc Tensioner
- Consist of two disc, which one pressed against each other through which yarn passes.
- Each disc is circular in shape which has flat portion with curved surface at the peripherally.
- Washers are placed on the top disc. These washer determine the normally force and there by tension impart.
- And a light spring may be kept between top disc and washers.
- Spring force and there the tension applied can be adjusted with a nu with the helped of which spring compression can be adjusted.
- Such disc tension yarn envelops around the pin of the tensioner which multiplicative tension component.
How to Minimize Tension Fluctuations
- Minimizing ballooning tension through selection of optimum guide distance during over end unwinding from a ring frame bobbin.
- Minimizing tension fluctuation by using on unwinding acceleration (balloon breaker).
- To minimize tension fluctuation by optimizing balloon formation.
- Regulating tension through change in winding used.
- Regulating tension by controlling tension applied by yarn tension.
REF:
- fundamentals of yarn winding by Milind Koranne (Woodhead Publishing India in
textile)
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