Baer's Comb Sorter
Baer’s Comb Sorter Diagram
Fibre Length:
The "length" of cotton fibres is a property of commercial value as the price is generally based on this character. To some extent it is true, as other factors being equal, longer cottons give better spinning performance than shorter ones. But the length of a cotton is an indefinite quantity, as the fibres, even in a small random bunch of a cotton, vary enormously in length. Following are the various measures of length in use in different countries
Mean length:
It is the estimated quantity which theoretically signifies the arithmetic mean of the length of all the fibres present in a small but representative sample of the cotton. This quantity can be an average according to either number or weight.
Upper quartile length:
It is that value of length for which 75% of all the observed values are lower, and 25% higher.
Effective length:
It is difficult to give a clear scientific definition. It may be defined as the upper quartile of a numerical length distribution eliminated by an arbitrary construction. The fibres eliminated are shorter than half the effective length.
Modal length:
It is the most frequently occurring length of the fibres in the sample and it is related to mean and median for skew distributions, as exhibited by fibre length, in the follwing way.
(Mode-Mean) = 3(Median-Mean) where, Median is the particular value of length above and below which exactly 50% of the fibres lie.
2.5% Span length:
It is defined as the distance spanned by 2.5% of fibres in the specimen being tested when the fibres are parallelized and randomly distributed and where the initial starting point of the scanning in the test is considered 100%. This length is measured using "DIGITAL FIBROGRAPH".
50% Span length:
It is defined as the distance spanned by 50% of fibres in the specimen being tested when the fibres are parallelized and randomly distributed and where the initial starting point of the scanning in the test is considered 100%.
Fibre Length:
The "length" of cotton fibres is a property of commercial value as the price is generally based on this character. To some extent it is true, as other factors being equal, longer cottons give better spinning performance than shorter ones. But the length of a cotton is an indefinite quantity, as the fibres, even in a small random bunch of a cotton, vary enormously in length. Following are the various measures of length in use in different countries
Mean length:
It is the estimated quantity which theoretically signifies the arithmetic mean of the length of all the fibres present in a small but representative sample of the cotton. This quantity can be an average according to either number or weight.
Upper quartile length:
It is that value of length for which 75% of all the observed values are lower, and 25% higher.
Effective length:
It is difficult to give a clear scientific definition. It may be defined as the upper quartile of a numerical length distribution eliminated by an arbitrary construction. The fibres eliminated are shorter than half the effective length.
Modal length:
It is the most frequently occurring length of the fibres in the sample and it is related to mean and median for skew distributions, as exhibited by fibre length, in the follwing way.
(Mode-Mean) = 3(Median-Mean) where, Median is the particular value of length above and below which exactly 50% of the fibres lie.
2.5% Span length:
It is defined as the distance spanned by 2.5% of fibres in the specimen being tested when the fibres are parallelized and randomly distributed and where the initial starting point of the scanning in the test is considered 100%. This length is measured using "DIGITAL FIBROGRAPH".
50% Span length:
It is defined as the distance spanned by 50% of fibres in the specimen being tested when the fibres are parallelized and randomly distributed and where the initial starting point of the scanning in the test is considered 100%.
References: 1. "TE05046PhysicalTextileTestingandQualityControl.doc." Www.most.gov.mm. MINISTRY OF SCIENCE AND TECHNOLOGY DEPARTMENT OF TECHNICAL AND VOCATIONAL EDUCATION GOVERNMENT TECHNOLOGICAL COLLEGES/INSTITUTES DEPARTMENT OF TEXTILE ENGINEERING, n.d. Web. <http://www.most.gov.mm/techuni/media/TE05046PhysicalTextileTestingandQualityControl.doc>. 2. Kohli, Nitesh. Fibre Testing. Scribd.com. N.p., 18 May 2009. Web. <http://www.scribd.com/doc/15569730/Fibre-Testing>. 3. "FIBRE TESTING." Textiletechinfo.com. N.p., n.d. Web. 25 July 2012. <http://textiletechinfo.com/spinning/fibretesting.htm>. 4. Tirumalai, Radhakrishna S. "General Chapters: COTTON." Http://www.pharmacopeia.cn. N.p., n.d. Web. 25 July 2012. <http://www.pharmacopeia.cn/v29240/usp29nf24s0_c691.html>