Yaa Merits In Addition To Limitations Of Cotton Fiber Fiber Length Measurement Instruments (Part-1)
Tuesday 18 December 2018
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Merits together with Limitations of Cotton Fiber Length Measuring Instruments (Part-1)
N.Balasubramanian
Retd Jt. Director (BTRA) together with Consultant
I, Rajeswari, 36, 17th Road, Chembur, Bombay 400071, 9869716298
Email: balajamuna@gmail.com
Retd Jt. Director (BTRA) together with Consultant
I, Rajeswari, 36, 17th Road, Chembur, Bombay 400071, 9869716298
Email: balajamuna@gmail.com
Abstract
Baer sorter is the most accurate musical instrument for measuring curt fibre content but is fourth dimension consuming together with requires operator training. HVI fibrograph though much faster suffers from 1overestimationdue to scanning some distance from clamping betoken 2. Underestimation equally sampling inwards the clamped beard is non genuinely length biased together with iii highly unreliable inwards estimating curt fibre content. AFIS is too rapid inwards measuring fibre length but suffers from fibre breakages during opening. Further fibres are non fully straightened during measurement. Almeter has the merit of giving both frequency distribution together with cumulative frequency distribution but curt fibres are non fully gripped together with motion to the centre. Image analyses is to a greater extent than accurate but is fourth dimension consuming. Considerable departure is works life betwixt the results of diverse authors nearly the score of understanding betwixt the results of unlike length measuring instruments.
Introduction:
Fibre length is 1 of the most of import lineament of cotton wool contributing to higher yarn force spinnability together with reduced terminate breakages inwards spinning. Short fibre content has pronounced number on waste, yarn irregularity, appearance together with terminate breakages Conventional together with HVI instruments used for testing fibre length parameters of cottons are briefly reviewed here. Merits together with limitations of these instruments, precautions to live taken together with the understanding betwixt the results of these instruments are discussed based on question conducted over the years.
Oil plate method
Fibre straightened past times liquid alkane series on a drinking glass plate is measured for length past times a scale. Merits – Accurate standard Limitation – Laborious together with fourth dimension consuming.
Balls Sorter
Determines frequency length distribution of fibres from which mean, CV are estimated. Fibres are set equally per their length on a plush tabular array past times a moving wagon together with fibres falling inwards unlike length groups are weighed to give weight length distribution (f(l)). Time consuming together with is non normally used.
Baer Sorter
The fibres are fractionated into unlike length groups past times a set of parallel combs together with superlative comb together with uniform array of fibres is prepared inwards descending guild of length to become cumulative fibre length distribution . Effective length, Mean length, Upper quarter length together with % curt fibres are determined. Suter spider web sorter is a similar American musical instrument where tufts are weighed instead of beingness set on a plush board to set upward a diagram. ASTM Standard D 1447-07, details the Standard Test Method for Length together with Length Distribution of Cotton Fibers (Array Method). Cumulative frequency past times Baer sorter is q(l) together with is related to frequency f(l) of fibres past times (balls sorter)
Merits-
- Effective length is unopen to Grader's staple length
- Provides accurate approximate of curt fibre content
Limitations-
- Time consuming (about 2 hrs per sample)
- Requires considerable operator skill.
Shirley Photo Electric Stapler
Light is made to autumn on a moving tuft of fibres aligned at 1 terminate together with the reflected lite is made to autumn on 2 photograph cells. Distance betwixt 2 maximum slope points inwards the electrical flow generated inwards the 2 photograph cells , equally the tuft moved on a traversing record gives staple length.
Peyer Almeter
Fibroliner prepares a beard of aligned fibres held inwards the needle champaign of a transfer equipment. The clamped beard is passed betwixt 2 capacitance plates together with the alter inwards capacitance is measured. Both cumulative together with histogram of length frequency bend are shown inwards a printer. Time taken for standard of length is nearly 15- twenty min. ASTM D5332- 92 stipulates exam method of measuring length past times Almeter. Limitation – Finite gauge of Fibroliner does non permit total gripping of curt fibres. Fibroliner allows curt fibres to motion to the centre of beard instead of staying at the aligned end1.
Fibrograph
Light is made to autumn on a moving tuft of fibres aligned at 1 terminate together with the reflected lite is made to autumn on 2 photograph cells. Distance betwixt 2 maximum slope points inwards the electrical flow generated inwards the 2 photograph cells , equally the tuft moved on a traversing record gives staple length.
Peyer Almeter
Fibroliner prepares a beard of aligned fibres held inwards the needle champaign of a transfer equipment. The clamped beard is passed betwixt 2 capacitance plates together with the alter inwards capacitance is measured. Both cumulative together with histogram of length frequency bend are shown inwards a printer. Time taken for standard of length is nearly 15- twenty min. ASTM D5332- 92 stipulates exam method of measuring length past times Almeter. Limitation – Finite gauge of Fibroliner does non permit total gripping of curt fibres. Fibroliner allows curt fibres to motion to the centre of beard instead of staying at the aligned end1.
Fibrograph
Beard of fibres is prepared past times picking the fibres randomly from the sample past times a comb together with free fibres brushed aside. The beard is optically scanned from the base of operations to tip from which a fibrogram is drawn. The comb has28 needles/inch. Since long fibres receive got a proportionally higher probability to live caught past times comb this results inwards a length biased sample. The musical instrument based on this regulation was developed past times Hertel2. Upper one-half hateful length, hateful length together with Uniformity index are determined from the fibrogram past times drawing tangents to the curve2. ASTM D1447 - 07(2012)e1 gives the Standard Test Method for Length together with Length Uniformity of Cotton Fibers past times instruments similar Fibrograph. Mechanisation of standard of length inwards the musical instrument resulted inwards servo fibrograph where fibrogram is drawn automatically. Manual models could too live converted to servo automatic model past times this conversion3. Time required per exam is reduced from 7.5 2nd to four 2nd together with operator fatigue reduced. Further improvements were suggested past times Tallant to improve accuracy inwards draw together with higher operator speed4. Rouse used 2 dial gauges to produce upward one's heed relative length of fibres together with number of fibres inwards a fibrogram instead of drawing the fibrogram5 for improving accuracy. Ewald together with Worley6 developed modifications to enable same fibrograph musical instrument to operate equally manual, an automatic bend drawing or an automatic dial or digital type. Hertel together with Craven7 introduced the concept of bridge length measurements which led to Digital fibrograph. Digital counters alongside force push systems were used inwards house of dial gauges together with the entire functioning of length standard is atomised. 2.5%, 50% bridge length, uniformity index together with curt fibre%, curt fibre content(SFL) together with Floating fibre index are determined inwards digital fibrograph. Fibro sampler is used inwards afterwards models to clamp the fibres on the comb. Fibre sample is pose within the cylinder of sampler. Fibre comb, alongside xiii needles/inch, is rotated around the fibro sampler, alongside force per unit of measurement area applied on the cotton, during which it picks upward fibres projecting from the holes of sampler. Time taken for standard is reduced to 1 2nd per sample alongside reproducibility of .1 to .18 %.
Merits
1. Because of fibre breakages together with length involved inwards clamping, estimates of length are lower.
2. Holding length calculated mathematically is works life to live around 4.06 mm8. Scanning starts at 3.81 mm from comb. As a final result actual scanning starts at 7.87 mm from the comb because of this. The belongings length too varies from cotton wool to cotton. Krowwicki together with Ramay9 showed that fifty % bridge length, 2.5 % bridge length together with Uniformity ratio inwards Digital Fibrograph are overestimated equally scanning starts at 3.81 mm from clamping point. fifty % together with 2.5 % bridge lengths are overestimated to the extent given below:
50% bridge length = 0.5 L + 1.905
2.5 % bridge length = 0.975 L + 0.09525
Maximum possible Uniformity Index is increased equally a final result from 51.28 to 57.6 for thirty mm together with 51.28 to 56 for xl mm cotton. The extent to which fibrogram is affected past times scanning at four mm from clamp seat instead of clamp is shown inwards Fig 1 together with Table 1 below. Both 2.5% together with fifty % bridge length are increased but the number is to a greater extent than on the latter. As a final result uniformity Index is increased.
3. Crimp inwards the fibre leads to underestimation.
Merits
- Simulates beard formed past times fibres held past times dorsum or forepart roller nip of a drafting organization
- Very rapid (about 1 - four 2nd per sample)
- Does non depend much upon operator skill.
1. Because of fibre breakages together with length involved inwards clamping, estimates of length are lower.
2. Holding length calculated mathematically is works life to live around 4.06 mm8. Scanning starts at 3.81 mm from comb. As a final result actual scanning starts at 7.87 mm from the comb because of this. The belongings length too varies from cotton wool to cotton. Krowwicki together with Ramay9 showed that fifty % bridge length, 2.5 % bridge length together with Uniformity ratio inwards Digital Fibrograph are overestimated equally scanning starts at 3.81 mm from clamping point. fifty % together with 2.5 % bridge lengths are overestimated to the extent given below:
50% bridge length = 0.5 L + 1.905
2.5 % bridge length = 0.975 L + 0.09525
Maximum possible Uniformity Index is increased equally a final result from 51.28 to 57.6 for thirty mm together with 51.28 to 56 for xl mm cotton. The extent to which fibrogram is affected past times scanning at four mm from clamp seat instead of clamp is shown inwards Fig 1 together with Table 1 below. Both 2.5% together with fifty % bridge length are increased but the number is to a greater extent than on the latter. As a final result uniformity Index is increased.
 |
| Fig 1 : Comparison of Fibrograms alongside scanning from clamp together with scanning from 4mm length |
Table-1: Span lengths together with uniformity ratios alongside scanning from clamp together with scanning from 4mm length
Span Length | Scanning from Clamp (Mm) | Scanning 4mm from clamp |
2.5 % | 31.67 mm | 32.05 mm |
50 % | 12.03 mm | 14.32 mm |
UI % | 40 | 44.7 |
3. Crimp inwards the fibre leads to underestimation.
4. Highly unreliable for estimating curt fibre content. Precautions required inwards fibre sampler for getting reliable beards are discussed past times Carpenter10. 1 Even force per unit of measurement area should live applied on the sample within cylinder 2. The cylinder should live rotated slow together with gently iii at to the lowest degree 1 one-half of perforations should live covered past times sample four beard should live uniform without thick together with sparse places v Influenza A virus subtype H5N1 fresh sample surface should live used for each comb 6. Excessive brushing of beard should live avoided. Yoakum11 reported a higher fibre length alongside fibro sampler beards than paw prepared beards. Correlation of yarn force alongside 2.5 % bridge length is equally adept equally the upper quarter length of comb sorter together with upper one-half hateful of servo fibrograph. 2.5 % bridge length past times digital fibrograph together with curt fibre % past times comb sorter were improve related to band frame terminate breakage charge per unit of measurement than uniformity ratio past times servo fibrograph.
Frequency of fibres of length l, r(l), past times fibrograph is a cumulative distribution of Baer sorter diagram together with is given past times
