Wrap Reel and Knowles Balance
Wrap reel and Knowles balance are basically used to make yarn lea and to measure the weight of that lea to achieve yarn count.
A beam balance is used in Knowles balance to know the count of any lea via its weight.
Knowles balance has a weight-measuring balance and behind that, a separate rod of the hexagonal section is mounted.
This hexagonal section comes with five faces lettered from A to E and engraved with a counting scale to cover a certain range.
This balance comes with five different weights and five different riders. Each of the five weights and rider has a particular letter from A to E.
To measure the count of lea, in the left-hand pan a lettered weight is placed, and on the beam a small lettered rider.
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| Knowles balance |
Suppose a cotton yarn is to be tested and is judged to be about 36s.
Face B of the scale is turned to the front, weight B is placed in the left-hand pane, and rider B is put on the beam.
The position of the rider is to be adjusted until the beam is balanced.
With adjusting of the rider, at a particular point rider's position balance the weight from both sides of the pan.
Note-down position of the rider and then read the count directly from the scale.
This balance can, of course, be designed to suit count systems other than that of cotton.
Quadrant Balance
Quadrant balance is used to measure the count of yarn, roving, and sliver.
It is more useful in the case of measuring the count of yarn, sliver, and roving from the small amount of sample.
Sometimes a small piece of fabric comes for testing and the count of warp and weft thread of a particular piece is required. Or the sometimes short lengths of sliver and roving have come for testing in the lab, In this case, Quadrant balance is very useful.
Its design is such a way that it can use to directly show the count of sliver roving and yarn when the sample size is small.
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| Quadrant balance |
This instrument consists of a simple beam, a quadrant scale, and a hook.
A simple beam is used to balance weight.
The hook is used to hang the specimen of yarn, sliver, or roving.
The quadrant scale is used to read the count of the sample
A given length is measured out and hangs in the hook, the count is then read directly from the quadrant scale.
The versatility of this type of balance is improved by engraving the scale with more than one series of values.
Before testing in Quadrant balance it is necessary to check its 0 positions on the scale.
i.e. - For cotton fibres, Cut warp and weft threads in specific lengths.
To measure the count of those warp and weft threads used to balance.
Thread, roving, and sliver have different markings on the quadrant scales to measure count.
For example,
1. one scale may read from 0.1 to 1.0 to give the hank of a 4-yard sample of sliver.
2. the Second scale may read from 0.1 to 0.6 for 20-yard samples of roving.
3. the Third scale may read from 4s to 80s for 840-yard samples of yarn.
When this is used in the analysis of small samples of thread, sliver, or roving, a rough estimate of the crimp should be made and the count correct.
Limitations of Quadrant balance
It is a very time-consuming and laborious process.
It is less efficient due to the higher number of error generations.
The scales just mentioned are in the cotton count system.
To measure other materials, separate quadrant balances are required for different ranges and different systems.
However, for the cheaper level of testing and for specific cotton materials this system is useful.
Questions -
- What is a yarn numbering system?
- Why wrap reel and Knowles balance is used?
- What is quadrant balance?
- How does quadrant balance work?
- What are the limitations of quadrant balance?
References
Lord, P. R. (2003). Handbook of yarn production: Technology, science and economics (1st ed.). Woodhead Publishing.
NPTEL IITm. (n.d.). Nptel.Ac.In. from https://nptel.ac.in/courses/116102029
Saville, B. P. (1999). Physical testing of textiles. Woodhead Publishing.
Testometric co. Ltd. (n.d.). Testometric.co.uk. from https://www.testometric.co.uk/
Yarn tests. (2019, July 23). ATIRA; Ahmedabad Textile Industry’s Research Association. https://atira.in/yarn-tests/
(N.d.). Textilelearner.net. from https://textilelearner.net/classification-of-textile-testing-fiber-testing-yarn-testing-fabric-testing/
Sayed, A. (n.d.). Yarn count: Definition and Types. Blogspot.com. from https://textileapex.blogspot.com/2014/01/yarn-count-types.html
Further reading -
(Part-1) Yarn count / Linear density of yarn
(Part-2) Yarn count - by Direct, indirect method
(Part-3) Yarn count measurement - preparation of hank
(Part-4) Yarn count measurement by wrap, Quadrant balance
(Part-5) Yarn count measurement - Beesley balance
(Part-6) Yarn count measurement - Shirley method
Writer - DSPAT Team
