ÇUKUROVA UNIVERSITY
INSTITUTE OF NATURAL AND APPLIED SCIENCES
PhD THESIS
Noorullah SOOMRO
IMPROVEMENT OF THE GINNING PROCESS IN PAKISTAN WITH
EMPHASIS ON THE DESIGN OF GIN-SAW BLADES
DEPARTMENT OF AGRICULTURAL MACHINERY
ADANA, 2011
ÇUKUROVA UNIVERSITY
INSTITUTE OF NATURAL AND APPLIED SCIENCES
IMPROVEMENT OF THE GINNING PROCESS IN PAKISTAN WITH
EMPHASIS ON THE DESIGN OF GIN-SAW BLADES
Noorullah SOOMRO
PhD THESIS
DEPARTMENT OF AGRICULTURAL MACHINERY
We certify that the thesis titled above was reviewed and approved for the award of
degree of the Doctor of Philosophy by the board of jury on 16- 02-2011.
…………………………….
…………………………
………………………………
Prof. Dr. Serdar ÖZTEKİN
SUPERVISOR
Prof. Dr. Emin GZÜEL
MEMBER
Prof. Dr. Oktay GENÇER
MEMBER
…………………………….……..
…… ………………………………
Assistant Prof. Dr. Sait M. SAY
MEMBER
Assistant. Prof. Selçuk ARSLAN
MEMBER
This PhD Thesis is written at the Department of Institute of Natural and Applied
Sciences of Cukurova University.
Code No:
Prof. Dr. İlhami YEĞİNGİL
Director
Institute of Natural and Applied Sciences
PS: It is strictly forbidden to use all citations, tables and figures in this thesis without
permission according to the law of intellectual properties-5846
ABSTRACT
PhD THESIS
IMPROVEMENT OF THE GINNING PROCESS IN PAKISTAN
WITH EMPHASIS ON THE DESIGN OF GIN-SAW BLADES
Noorullah SOOMRO
ÇUKUROVA UNIVERSITY
INSTITUTE OF NATURAL AND APPLIED SCIENCES
DEPARTMENT OF AGRICULTURAL MACHINEY
Supervisor : Prof. Dr. Serdar ÖZTEKİN
Year: 2011, Pages: 97
Jury
: Prof. Dr. Emin GÜZEL
: Prof. Dr. Oktay GENÇER
: Asst. Prof. Dr. Sait M. SAY
: Asst. Prof. Dr. Selçuk ARSLAN
Cotton is the world`s most widely used textile fiber, the quality of which is
extremely critical for successful textile processing. The quality of baled cotton
depends on many factors including variety, weather conditions, cultural applications,
harvesting and storage practices, moisture, trash content and ginning processes. The
problem in ginning of cotton in Pakistan is that while separating lint from seed; the
ginning machines damage the cotton fiber as well as seed because of outdated local
machinery. In this thesis, the research has been done for modification of the existing
ginning process with emphasis on the design and development of gin-saw blade as to
improve the spinning characteristics of lint cotton. In the thesis, the research has been
done for modification of the existing ginning process with emphasis on the design
and development of gin-saw blade as to improve the spinning characteristics of lint
cotton. The thesis consists of two basic studies; (a) Questionnaire in existing ginning
factories in Turkey and Pakistan, (b) Design, manufacturing and testing of new ginsaw blades on lab scale gin stand in Pakistan. The questionnaire in ginning industry
of Pakistan and Turkey was prepared to transfer know-how and technology from
Turkey to Pakistani ginneries. One of important outcome was the necessity of new
gin saw design. The designed and manufactured gin-saw types were subjected to
comparative ginning testing on lab gin stands to study effects of different designs of
gin-saws on ginning and lint quality. According to statistical evaluation the best
result was obtained at the tooth angle of 24°. Cotton ginning by modified saw is
practically possible and is wholly favorable to ginning even on bulk level.
Key words: Cotton, ginning, gin saw blade.
I
ÖZ
DOKTORA TEZİ
SAWGİN BIÇAKLARINDA YAPILAN TASARIM DEĞİŞİKLİĞİ İLE
PAKİSTAN’DA ÇIRÇIRLAMA İŞLEMİNİN GELİŞTİRİLMESİ
Noorullah SOOMRO
ÇUKUROVA ÜNİVERSİTESİ
FEN BİLİMLERİ ENSTİTÜSÜ
TARIM MAKİNALARI ANABİLİM DALI
Danışman : Prof. Dr. Serdar ÖZTEKİN
Year: 2011, Pages: 97
Jüri
: Prof. Dr. Emin GÜZEL
: Prof. Dr. Oktay GENÇER
: Yard. Doç. Dr. Sait M. SAY
: Yard. Doç. Dr.Selçuk ARSLAN
Pamuk dünyada en yaygın kullanılan lif materyali olup, kalitesi başarılı bir
tekstil üretim işlemi için son derece önemlidir. Balyalanmış pamuğun kalitesi çeşit,
kültürel uygulamalar, hasat, depolama işlemleri, ürün nemi, yabancı madde içeriği ve
çırçırlama işlemi gibi bir çok etkene bağlıdır. Pakistan’daki çırçırlama işleminde
tohumdan lifin ayrılması işleminde karşılaşılan temel sorun, eski model
makinalardan oluşan çırçır sisteminin hem life, hem de tohuma zarar vermesidir. Bu
tezde sawgin bıçaklarında yapılan tasarım ve geliştirme ile mevcut çırçırlama
işleminde iyileştirme yapılmış ve bu yolla pamuğun lif kalitesi yükseltilmesi
amaçlanmıştır. Bu kapsamda tez iki kısımdan oluşmaktadır; (a) Türkiye ve
Pakistan’daki çırçır fabrikalarında yapılan anket çalışması, (b) Yeni sawgin
bıçaklarının tasarımı, imalatı ve laboratuar ölçeğindeki bir prototip çırçır ünitesinde
denenmesi. Anket çalışması Türkiye’deki çırçır fabrikalarında kazanılan
deneyimlerin ve teknolojinin Pakistan’a aktarılması için yapılmıştır. Anketten çıkan
sonuç yeni sawgin bıçaklarının gerekliliğini ortaya koymuştur. Bunun üzerine farklı
profil ve diş açılarıyla yeni sawgin bıçakları tasarlanıp, imal edilmiş ve prototip
sawgin sistemi üzerinde denenmiştir. Yapılan istatistiksel karşılaştırmaya göre
24°’lik diş açısı tüm kalite kriterleri açısından en uygun tasarım olarak görülmüştür.
Pamuk çırçırlama işlemi bu geliştirilen bıçak sayesinde istenen kalite yükselmesini
sağlayacaktır.
Anahtar kelimeler: Pamuk, çırçırlama, gin saw bıçak.
II
ACKNOWLEDGEMENTS
I have the honor to present this thesis on my PhD topic in fulfillment of the
Degree of Doctor of Philosophy.
I would like to express my heartfelt thanks to my mentor and respected
supervisor Prof. Dr. Serdar ÖZTEKİN for his guidance, encouragements, suggestions
and endless support with patience through the write-up of my thesis.
I wish to thank Dr. Muhammad Mureed Kandhro, Deputy Chief Scientist,
Atomic Energy Agricultural Research Center, Tando Jam, Sindh, Pakistan for his
valuable advices and permission to carry out experiments of my custom designed gin
saws on laboratory gin at his research center. I have a lot of thanks to give to
Dr.Ahmet İnce and Mr. Irfan ALKAŞ for their unforgettable expertise.
I am grateful to Prof. Dr. Emin GÜZEL, Head of Department for permitting
me to utilize all the department facilities. I am very thankful to Prof. Dr. Oktay
GENÇER for his many helpful suggestions and support.
DEDICATION
This research is dedicated to my loving family for their prayers, love,
patience, encouragement and tremendous support to achieve my goal:
Dr. Najeebullah Soomro (Son)
Dr. Mariam Soomro (Daughter)
Mrs. Manzoor Siddiqui (Spouse)
Mr Habibullah Soomro (Brother)
Mr. Abdul Haque Soomro (Late father)
Mrs. Aamina Soomro (Late mother)
III
CONTENTS
PAGE
ABSTRACT .................................................................................................................. I
ÖZ .............................................................................................................................. II
ACKNOWLEDGEMENTS .........................................................................................III
DEDICATION ............................................................................................................III
CONTENTS ............................................................................................................... IV
FIGURES ................................................................................................................... VI
TABLES .................................................................................................................. VIII
1.
INTRODUCTION ................................................................................................. 1
1.1. Cotton Production in the World ......................................................................... 1
1.2. Cotton Production in Pakistan ........................................................................... 5
1.2.1. Cotton Processing in Pakistan .....................................................................11
1.2.1.1. Ginning ............................................................................................. 12
1.2.1.1.(1). Saw Gin System ..................................................................... 18
1.2.1.1.(2). Roller Gin System ................................................................... 21
1.2.1.1.(3). Comparison of Roller Gin and Saw Gin ................................... 23
1.2.1.1.(4). Post-ginning Operations .......................................................... 24
1.2.1.2. Ginning Industry of Pakistan ............................................................. 26
2.
PREVIOUS STUDIES .........................................................................................29
3.
OBJECTIVES OF THE RESEARCH ...................................................................33
4.
MATERIALS AND METHODS ..........................................................................35
4.1. Questionaire .....................................................................................................35
4.2. The Status of Local Manufactured Gin-Saw Blade ...........................................37
4.3. Design of New Gin Saw Blade .........................................................................39
4.4.
5.
Design Modification .....................................................................................41
RESULTS AND DISCUSSION ...........................................................................47
5.1. Results of Questionnaire and Observations .......................................................47
5.2. Results of Prototype Testing ..........................................................................55
5.3. Discussion of Prototype Testing .......................................................................71
6.
CONCLUSION ....................................................................................................79
IV
6.1. Principle Sketch of Modification ......................................................................79
6.2. Recommendations ............................................................................................84
REFERENCES .......................................................................................................87
CURRICULUM VITAE .........................................................................................91
APPENDIX ............................................................................................................95
V
FIGURES
PAGE
Figure 1.1. Cotton ready to harvest (USDA, 2001)......................................................... 1
Figure 1.2. World cotton production (ERS, 2009) .......................................................... 2
Figure 1.3. World cotton mill use (ERS, 2009) .............................................................. 3
Figure 1.4. Mohen Jo Daro (Anonymous, 2002) ............................................................ 5
Figure 1.5. Cotton field in Pakistan (PCGA, 1999) ........................................................ 7
Figure 1.6. Cotton field plowing (own photo) .............................................................. 11
Figure 1.7 Typical layout of gin processing line (Anonymous, 2006a) ......................... 11
Figure 1.8 .Typical cotton gin (Anonymous, 2001) ...................................................... 12
Figure 1.9. Cotton is received in the factory (own photo) ............................................. 13
Figure 1.10. Cotton selection (own photo) ................................................................... 13
Figure 1.11. Drying of seed cotton (own photo) ........................................................... 14
Figure 1.12. Artificial dryer (Anonymous, 2001) ......................................................... 14
Figure 1.13. Storing of seed cotton in modules (own photo)......................................... 15
Figure 1.14. Ventilating machine (own photo) ............................................................. 16
Figure 1.15. Pre-cleaner (Anonymous 2001) ................................................................ 16
Figure 1.16. Rock catcher (Anonymous, 2001) ........................................................... 17
Figure 1.17. Inclined cleaner (Anonymous, 2001) ....................................................... 18
Figure 1.18. Gin stand (Anonymous, 2010a) ................................................................ 19
Figure 1.19. Gin saw blade (own photo) ...................................................................... 20
Figure 1.20. Roller gin stands (Anonymous, 2006b) .................................................... 21
Figure 1.21. Typical roller gin (Anonymous, 2001) ..................................................... 22
Figure 1.22. Bale press (own photo)............................................................................. 26
Figure 1.23. Bale handling (own photo) ....................................................................... 26
Figure 1.24. Local gin saw blade (own photo).............................................................. 28
Figure 1.25. Manual saw sharpening operation (own drawing) ..................................... 28
Figure 2.1. The Merrill E. Pratt cotton gin, general view (Anonymous, 2010b) ............ 30
Figure 2.2. The Merrill E. Pratt Cotton Gin view of gin saws (Anonymous, 2010b) ..... 31
Figure 2.3. View of gin-saw blade No. 5,229 (Anonymous, 2007) ............................... 32
Figure 4.1. Pitch angle with tooth entering the throat (own photo) ............................... 38
VI
Figure 4.2. Local made gin-saw with straight teeth & throat angle of 29° (own photo) . 38
Figure 4.3. Formulation of scientific design and development of gin-saw blade ........... 39
Figure 4.4.. Stages for a new product design ................................................................ 40
Figure 4.5 Scheme of comparison of standard saw with the modified designs. ............. 42
Figure 4.6. Magnified profile view of local saw ........................................................... 43
Figure 4.7. Modified gin-saw blade with curved teeth angle of 24 ° ............................. 44
Figure 4.8. Modified gin-saw blade with curved teeth angle of 24 ° ............................. 45
Figure 4.9. The prototype gin stand. (Anonymous, 2009) ............................................. 45
Figure 5.1. Sketch of original ginnery .......................................................................... 49
Figure 5.2. Common problem is saws while ginning .................................................... 53
Figure 5.3. Frequency of saw tooth damage observed by ginners ................................. 54
Figure 5.4. Opinion on gin saw design improvement lead to better quality fiber ........... 55
Figure 5.5. Most important factor to ginners after ginning............................................ 55
Figure 5.6. Lab gin stand with various gin saw blades .................................................. 56
Figure 5.7. Mean GOT value analysis between 24° & 29°............................................ 61
Figure 5.8. GOT at 24° and 29 º for Naib-78 ................................................................ 64
Figure 5.9. Graphical results ........................................................................................ 73
Figure 5.10. GOT % of Niab-78 at different tooth angle .............................................. 74
Figure 5.11. UR % of Niab-78 at different tooth angles ............................................... 74
Figure 5.12. Strength of Niab-78 at different tooth angles ............................................ 75
Figure 5.13. Short fiber content of Niab-78 at different tooth angles ............................ 76
Figure 5.14. GOT % Of MNH-93 at different tooth angles ........................................... 76
Figure 5.15. UR % of MNH-93 at different tooth angles .............................................. 77
Figure 5.16. Strength of MNH-93 at different Tooth Angles ........................................ 77
Figure 5.17. Short Fiber Content of MNH-93 at different tooth angles ......................... 78
Figure 6.1. Sketch of original ginnery .......................................................................... 80
Figure 6.2. Sketch of modified ginnery…………………………………………….......81
VII
TABLES
PAGE
Table 1.1 Pakistan's Cotton Production and Yield Target (Anonymous, 2010c) ........ 6
Table 1.2 Fiber characteristics of commercial cotton varieties in Pakistan ................. 8
Table 1.3. Export of Pakistan’s Raw Cotton at a Glance (APTMA, 2008) ................. 9
Table 1.4. Country-wise Export of Raw Cotton (APTMA, 2008) ............................ 10
Table 1.5. Rotational Speeds of Cylinders on Roller Gin ........................................ 23
Table 4.1. Chemical Test Report of Improved Gin-Saw Blade ................................ 41
Table 4.2. Mechanical Test Report of Improved Gin-Saw Blade ............................. 41
Table 5.1. Inventory of Problems Observed while Ginning ..................................... 51
Table 5.2. Descriptive Statistical Analysis with Confidence Interval for Naib78 ..... 60
Table 5.3. ANOVA with Degree of Freedom (df) for Naib-78 ................................ 61
Table 5.4. Means for Groups in Homogeneous Subsets are Displayed .................... 62
Table 5.5. Experimental Testing Results for Modified Saw ..................................... 63
Table 5.6. Group Statistics ...................................................................................... 64
Table 5.7. Independent Samples t-Test.................................................................... 65
Table 5.8. Lint Characteristics ................................................................................ 66
Table 5.9. ANOVA of Fiber Variables in Naib-78 .................................................. 67
Table 5.10. ANOVA for GOT in MNH-93 Variety ................................................. 68
Table 5.11. Tukey HSD Multiple Comparisons ....................................................... 69
Table 5.12. Post Hoc Homogenous Subset Comparisons ......................................... 70
Table 5.13. ANOVA of Fiber Variables in MNH-93 ............................................... 71
VIII
IX
1. INTRODUCTION
Noorullah SOOMRO
1. INTRODUCTION
Cotton is one of the most important textile fibers in the world, accounting for
around 35 percent of total world fiber use. Cotton is a soft, fluffy staple fiber that
grows in a boll around the seeds of the cotton plant (Figure 1.1). The plant is a shrub
native to tropical and subtropical regions around the world, including the Americas,
Africa, India, and Pakistan. The fiber most often is spun into yarn or thread and used
to make a soft, breathable textile.
Figure 1.1. Cotton ready to harvest (USDA, 2001)
1.1. Cotton Production in the World
According to International Cotton Advisory Committee (ICAC), cotton is
grown as a major agricultural and industrial crop in Australia, Brazil, China
(Mainland), Greece, India, Pakistan, Syria, Turkey, USA and Uzbekistan producing
around 80% of the total crop in the world (ERS, 2009). The largest cotton producing
country is China. While some 80 countries from around the globe produce cotton, the
United States, China, and India together provide two-thirds of the world's cotton
(Figure 1.2). The United States, which ranks third in production behind China and
India, is the leading exporter, accounting for over one-third of global trade in raw
cotton (USDA, 2001). India is the second largest producer while Pakistan is ranked
1. INTRODUCTION
Noorullah SOOMRO
number fourth. Uzbekistan is the fifth largest cotton producing country and is
expected to produce 1.0 million tons, or 25% of the cotton produced in the USA. The
United States Department of Agriculture (USDA) estimates that 19.2 million ton of
the cotton was produced in the world during 2010-11 (ERS, 2009). Compared with
production of 19.2 million tons, consumption is expected to be 20.0 million tons
during 2010/11, an increase of around 60,000 tons. International commodity prices
will continue to play a role, and cotton consumption is expected to continue upward
next season.
Figure 1.2. World cotton production (ERS, 2009)
Trade is particularly important for cotton. Sharp increases in crude oil prices
raised the opportunity cost of chemical fibers for the textile industry. Lower cotton
prices relative to chemical fibers and faster world economic growth are boosting
cotton consumption in the world.
About 30 percent of the world's consumption of cotton fiber crosses
international borders before processing, a larger share than for wheat, corn, soybeans,
or rice. (ICAC, 2010) Through trade in yarn, fabric, and clothing, much of the
world's cotton again crosses international borders at least once more before reaching
1. INTRODUCTION
Noorullah SOOMRO
the final consumer. Pakistan is ranked 3rd behind India and China in world for cotton
mill use (Figure 1.3).
Figure 1.3. World cotton mill use (ERS, 2009)
The average yield in India and the USA are expected to increase, but a
decline is expected in China (Mainland). However, the largest drop in average yields
is expected to occur in Pakistan due to the recent floods (ICAC, 2010).
Production technology may have improved in the last ten years and
technology is being developed with the same efforts as has been in the past but its
impact on yield at the world level has not been visible since 2002/03. It is a challenge
for everyone working in the field of production research to find ways and means to
improve yields. Such effort have to be different from traditional approaches aimed at
developing high yielding varieties, agronomic management practices and insect pest
control. Improvements in traditional cultivation practices would affect yields
positively, but a sustained increase in yields requires a non-traditional technological
innovation. It is a challenge for researches to develop such technology. Recently,
breeders, with the help of biotechnologists, have acquired a technology that can be
employed towards productivity improvement in addition to agronomic features of the
plant (ERS, 2009).
The cost of production has increased to unacceptable levels in many countries
thus threatening the economics of cotton production. Countries have gone out of
1. INTRODUCTION
Noorullah SOOMRO
cotton production because of high costs. There cannot be one threshold cost of
producing a kilogram of cotton, but if the increase in the cost of production is not
arrested, more countries may not find cotton feasible to grow. But the increases in
the cost of production have to be closely monitored and curtailed.
The latest studies of ICAC show that the cost of production ranges from less
than 50 cents to over US$ 2.5/kg lint (ICAC, 2010). Such a variation shows that the
cost can be decreased and it is a great challenge for the researchers to do so as the
farmers are willing to accept the current yield level if the cost of production can be
reduced. There is a need to find less expensive ways to grow cotton.
One of the other significant challenges in cotton production is to control the
insects with a minimum use of pesticides. There are increasing concerns about
insecticides than other pesticides and cotton producing countries throughout the
world wish to get away from pesticide-intensive production practices. One of the
reasons is of course the high cost of pesticides, but it is not the only reason.
Researchers and farmers are now more conscious about the long-term impact of
pesticides on production practices, the environment, sustainability and the pest
complex. But farmers cannot quit using pesticides until they have alternate pest
control methods. It is another challenge for researchers to develop pesticides free of
pest control technology (Gulyasar, 2000a).
Integrated Pest Management (IPM) has been talked about a lot and its
implementation has been very low. Recently, the Food and Agriculture Organization,
with financial help from the European Union, has started a five-year project in
Bangladesh, China (Mainland), India, Pakistan, Philippines and Vietnam (Gulyasar,
2000a). Through the farmer field school system, the project is devoted to
implementation of an IPM strategy.
Well-focused research is going on in the field of measuring fiber quantity
characteristics (Seagull et al, 2001). It is challenge for the producer to meet the
quality needs of the industry and to prove the raw materials qualitative value.
Methods to measure short fiber contents must be improved, so that responsibility of
the data among labs can be improved. Similarly, efficient methods to measure
stickiness have to be found (Gulyasar, 2000b).
1. INTRODUCTION
Noorullah SOOMRO
1.2. Cotton Production in Pakistan
Pakistan’s cotton is unique among agricultural crops no one knows how old
the cotton plant is. One of the first archeological discoveries of cotton usage in the
world is located in Pakistan at Mohen Jo Daro (Figure 1.4).
Cotton symbolizes a rich cultural heritage of Pakistan. Pakistan is the home
of cotton. It plays a vital role in the country’s economy. Cotton is a cash crop and has
contributed towards a substantial export earnings of Pakistan since its independence
in 1947. Cotton contributes heavily to the country’s foreign exchange through the
export of raw cotton, cotton yarn, finished cloth and readymade garments.
Cotton is mainly grown in the two provinces of Pakistan, i.e., the Sindh and
Punjab. The bulk of the cotton grown in the country is consumed by local textile
mills and other processing industries and the surplus left over which is quite
substantial, is exported. Thus, cotton has assumed its rightful role as the white gold
of Pakistan.
Figure 1.4. Mohen Jo Daro (Anonymous, 2002)
Pakistan has produced almost 9.3 million bales of cotton during 2009-10 crop
season (PCGA, 2010). Currently Pakistan is 4th largest producer in the world. The
Government of Pakistan set cotton production target for 2010-11 at 14 million bales
1. INTRODUCTION
Noorullah SOOMRO
(Anonymous, 2010a). While last year the estimated production was 12.7 million
bales. However, the targets of area, production and yield for next 3-5 years are given
in Table 1.1.
Table 1.1 Pakistan's Cotton Production and Yield Target
(Anonymous, 2010c)
AREA
PRODUCTION
YIELD
(million hectares)
(million bales)
(kgs per hectares)
3.2
20
600
Cotton is occupying about 11% of the cropped area in Pakistan. Cotton and cotton
textiles together contribute about 50% to the country`s export earnings. The
production of upland varieties constitute 95% and Desi (short staple) 5% or even less
of the total cotton production of the country (PCCC, 1999). Table 1.2 shows the
cotton varieties under commercial cultivation in Pakistan. Annual export of
Pakistan’s raw cotton and country wise export is shown in Table 1.3 and Table 1.4,
respectively.
In Pakistan most of cotton is handpicked (Figure 1.5). It is favorably placed
in the group of medium and long staple which is in great demand in the world’s
market. Machines are absent from this sustainable farm, Oxen are used for plowing
and powering (Figure 1.6).
1. INTRODUCTION
Noorullah SOOMRO
Figure 1.5. Cotton field in Pakistan (PCGA, 1999)
Unfortunately, the growers in Pakistan have not been able to get the price
commensuration with their cost of production due to certain reasons. One of the
major factors for this has been to be poor quality of ginned cotton, which is
sometimes not suitable for export in the international market.
1. INTRODUCTION
Noorullah SOOMRO
Table 1.2 Fiber characteristics of commercial cotton varieties in Pakistan
Pressley
Research
Sr. No.
Variety
Length
tensile
Program of
G.O.T
Staple
Micronaire
(000 lbs)
evolution
%
(inch)
value
per sq. inch
PUNJAB
UPLAND TYPE
1.
B-557
P.C.C.C.
34.5
1-1/32
4.45
92.9
2.
MNH-93
Agri. Deptt.
36.5
1-1/8
4.47
94.0
NIAB,
3.
NIAB-78
Faisalabad
36.6
1-1/32
4.46
92.5
4.
MS-84
Agri. Deptt.
34.0
1-1/4
3.90
91.3
5.
SLH-41
P.C.C.C.
34.0
1-1/32
4.40
95.8
6.
M-4 NT
P.C.C.C.
33.0
15-16
3.3/4.5
85.0
7.
M-100)
34.0
1-1/32
3.5/4.0
85.0
34.0
1-1/8
3.3/3.7
90.0
34.0
1-1/8
3.5/3.7
92.7
SINDH
H-598.
1(Qalandari)
S-59-1
9.
(Sarmast)
10.
K-68/9
P.C.C.C.
33.0
1-3/16
4.3/
96.1
11.
TH-1101
Agri.Deptt.
35.0
1-1/16
4.0/4.4
89.0/90.0
PUNJAB
DESI TYPE
12.
D-9
P.C.C.C
39.0
3/8-5/8
7.5
80.0
13.
Ravi
P.C.C.C
41.0
3/8-5/8
8.0
-
14.
TD-1
P.C.C.C.
39.8
11/16
10/10.2
79.5
15.
SKD-10/19
P.C.C.C.
-
3/8-5/8
9.6/10.2
-
SINDH
8
1. INTRODUCTION
Noorullah SOOMRO
Table 1.3. Export of Pakistan’s Raw Cotton at a Glance (APTMA, 2008)
Period
Quantity
Value
Value
Unit Value
000 Kg.
000 US $
000 Rs.
$/ Kg.
Rs/Kg.
1991-92
281,731
411,812
9,553,400
1.46
45.94
1992-93
455,217
518,302
12,943,900
1.14
28.43
1993-94
262,918
270,813
7,000,700
1.03
26.63
1994-95
74,899
79,461
2,383,200
1.06
31.82
1995-96
31,009
62,082
1,924,331
2.00
62.06
1996-97
310,930
506,765
17,421,321
1.63
56.03
1997-98
20,958
30,749
1,239,384
1.47
59.14
1998-99
88,650
126,139
5,482,631
1.42
61.85
1999-00
1,748
2,327
116,354
1.33
66.56
2000-01
82,959
72,560
3,760,760
0.87
45.33
2001-02
135,094
138,138
8,072,481
1.02
59.75
2002-03
34,926
24,581
1,493,295
0.70
42.76
2003-04
55,100
49,016
2,875,000
0.89
52.18
2004-05
37,307
47.671
2,744,419
1.28
73.56
2005-06
117,084
109,957
6,545,740
0.94
55.91
2006-07
62,658
68,151
4,080,000
1.09
65.12
2007-08
45,065
50,226
3,045,202
1.11
67.57
2008-09
57,124
70,122
4,386,131
1.23
76.78
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1. INTRODUCTION
Noorullah SOOMRO
Table 1.4. Country-wise Export of Raw Cotton (APTMA, 2008)
Countries
2007-08
2006-07
% Copy
Indonesia
21,966
19,151
14.70
Bangladesh
17,404
18,160
-4.16
Thailand
4,777
5,278
-9.49
China
4,558
50
9016.00
Hong Kong
3,676
697
427.40
Viet Nam
1,351
2,640
-48.83
Italy
329
64
414.06
India
122
0
0.00
South Africa
73
0
0.00
United Kingdom
67
-
0.00
France
66
-
0.00
Netherlands
63
-
0.00
Korea
41
-
0.00
UAE
7
267
-97.38
Others Countries
15,622
3,919
298.62
Total
70,122
50,226
39.61
All values given in ‘000’ US $
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1. INTRODUCTION
Noorullah SOOMRO
Figure 1.6. Cotton field plowing (own photo)
1.2.1. Cotton Processing in Pakistan
The ginning process has undergone a high degree of automation. These
generally all operations such as feeding, drying, pre-cleaning, ginning lint-cleaning
and pressing form successive continuous stages of a single integrated system. The
whole processing system is automated from seed cotton to the baled lint (Anthony et
al, 1984). It is electronically controlled and the entire plant can be controlled by a
single person in the central console. The typical layout of processing line is as
follows in Figure 1.7.
Figure 1.7 Typical layout of gin processing line (Anonymous, 2006a)
(1.Boll trap, 2. Separator, 3. Tower drier, 4. Separator, 5.Inclined cleaner 6.Lint cleaner 7.Condenser,
8. Fan, 9. Slide, 10. Bale press, 11. Bale lifter, 12. Weighing machine)
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1. INTRODUCTION
Noorullah SOOMRO
From serial no. 1 to 5 are pre-cleaning machines including the Gin stand
which is the heart of the ginning process. Serial no 7 to 10 are post-cleaning
machines.
1.2.1.1. Ginning
Cotton ginning is a complex and professional job requiring full time attention
to various aspect and stages of ginning (Basra, 1999). The act of separating lint form
seed by mechanical means, to give spin able cotton lint and undamaged seed, this
process is called ginning (USDA, 2001). Figure 1.8 shows a sketch of typical gin
cotton gin used in ginning factories.
Figure 1.8. Typical cotton gin (Anonymous, 2001)
The steps from raw cotton intake to ginning in processing plant are briefly
described below:
Selection: When seed cotton is received in the factory (Figure 1.9); the first step is to
do the selection work which is based on staple grade and moisture content. Figure
1.10 shows the cotton selection work being done in a factory. The seed cotton bags
with excessive moisture content in seed cotton are separated and dried so as to avoid
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1. INTRODUCTION
Noorullah SOOMRO
weight losses and the danger of their heated up/discoloring. Moisture is a key factor
affecting fiber quality during the ginning process. 7% is the ideal ginning moisture
content.
Figure 1.9. Cotton is received in the factory (own photo)
Figure 1.10. Cotton selection (own photo)
Drying: There are two methods of drying; natural and artificial drying system. The
seed cotton, because of morning humidity is often too wet to gin without some
drying. Therefore, especially in Pakistan seed cotton is dried generally through
natural system (Figure 2.4). Seed cotton that is wet will not gin satisfactorily. The
method for natural drying is to spread the seed cotton on a platform and expose it to
the sun for several hours during this workers move the cotton heaps up and down.
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1. INTRODUCTION
Noorullah SOOMRO
In some areas of coast-region, there is so much wet cotton that almost always
been made to dry it before ginning, therefore they use artificial dryer (Figure 1.11).
Some of these driers dry the seed cotton by pressing it through a large cylinder or
tower through which forced a hot air at the rate of 1.132 to 28.316 m3 for each pound
of cotton and the temperature of the drying is 65 to 121°C (Figure 1.12).
Figure 1.11. Drying of seed cotton (own photo)
INLET
OUTLET
Figure 1.12. Artificial dryer (Anonymous, 2001)
Storing seed cotton: Seed cotton can be safely stored in modules/heaps not more
than 5.48 x 3.66 x 3.05 m (L x W x H) meters, if its moisture content is kept at 12%
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1. INTRODUCTION
Noorullah SOOMRO
or less (Figure 1.13). Wet cotton or containing green plant material will heat during
storage and quickly deteriorate. Cotton damage in this manner produces low grade
and poor quality seed. Modules/heaps should be checked daily. A ventilating
machine should be used to save the seed cotton modules from heating or discoloring
(Figure 1.14).
Pre-ginning machines: The use of pre-ginning machines is of paramount
importance for production of high grade cotton. Pre-cleaner shown is Figure 1.15 is
intended to prepare the seed cotton for actual ginning and improving the quality of
lint. As we know that large amount of trash is added to the seed cotton right from
harvesting to the feed plate form. This trash consists of green bolls, burrs or hulls,
sticks, stems leaves, motes, grass, weeds, sand, dust, etc. These foreign matters
obstruct the actual ginning and cause ware of the ginning machinery and ultimately
deteriorate the lint grade. Therefore series of pre-cleaning operations are conducted
by using these equipments.
Heap settler: The main function of heap settler is to reduce the moisture content and
to loosen the condensed cotton. Then in heap settler cotton is fed manually from the
heap to the suction duct. Seed cotton is loosened by the beating action of the
separator. Finally the loose cotton is blown out onto a platform for further storage
and processing.
Figure 1.13. Storing of seed cotton in modules (own photo)
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1. INTRODUCTION
Noorullah SOOMRO
Figure 1.14. Ventilating machine (own photo)
Figure 1.15. Pre-cleaner (Anonymous 2001)
Rock & boll trap or rock catcher: A device for separating heavier materials form
the seed cotton, rock catcher is a very use-full device which can be made out of G.1
pipes and can be easily fitted in seed cotton suction line at a convenient place. This
device does not let the bricks; wooden pipes and immature cotton in ginning and
protects the costly spares of saw-gin machines. Figure 1.16 shows a rock catcher.
Separator: The main function of the separator in the gin outfit is to separate the
seed cotton from the conveying air. The separator is the first machine in the ginning
to receive seed cotton.
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1. INTRODUCTION
Noorullah SOOMRO
Cleaner/Opener: This is a simple two-spiked roll machine to clean and open the
seed cotton before ginning, as loose and fluffy seed cotton will result in improved
quality of ginning.
Figure 1.16. Rock catcher (Anonymous, 2001)
Air line cleaner and inclined cleaner: An airline cleaner is one in which the seed
cotton is conveyed while in the gin suction piping i.e. in the airline. An inclined
cleaner is a machine consisting of 4 to 6 spiked rolls. The length of spikes is
generally 1-1/4”and there are ¼” in diameter and an underneath wire netting of 3
mesh x 12 gauge. Spikes of the rolls open the seed cotton and the leaf and dust
separated from it Figure 1.17.
Impact cleaner: This machine has generally 2 rows of saw-toothed rolls and it also
does good cleaning of seed cotton. This machine also used for cleaning of seed
cotton before ginning.
Stick machine: A machine for removing sticks and green leaf from seed cotton and
is consists of reclaimed cylinder, with grid bars.
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1. INTRODUCTION
Noorullah SOOMRO
Figure 1.17. Inclined cleaner (Anonymous, 2001)
Feeder extractor cleaner: This machine is the best of cleaning dust, leaf and
particularly the bolls from seed cotton. It consists of feeder rolls, beater rolls, kicker
rolls, kicker rolls; channel saw rolls, bristle brush rolls and steel reclaimed brush.
1.2.1.1.(1). Saw Gin System
This saw gin system consists of following machines (Figure 1.18);
§
feeder rolls
§
pre-cleaner rolls
§
ginning saws
§
ginning rib
§
hulling ribs
§
hulling roll and
§
nozzle
The correct repair, setting operation at the right speed and regular
maintenance and repair of gin stand and its parts has great bearing on the quality of
ginning.
Essentially, the saw gin consists of a series of small circular saws, between
(12 –18 inch) in diameter, mounted closely on an axle and made to rotate at high
speed in order to tear/ pull the lint fibers away from seed. The seed cotton is fed
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1. INTRODUCTION
Noorullah SOOMRO
continuously into a rounded box or rough of gin-stand through the huller ribs and the
action of saw keeps it revolving in a loosely compacted roll. The seed falls through a
grid in to a collecting box or seed conveyor, while the lint is wiped off the teeth of
the saws by high speed brushes or an air blast. After passing through a condenser, is
conveyed to the bale press mechanically or pneumatically.
Figure 1.18. Gin stand (Anonymous, 2010a)
Saw gins may be classified as brush gin and air blast gin. Brush gin is so
called, because about 18” cylindrical brush, having about 30 longitudinal narrow
brushes. They revolve at a greater rate than the saws to separate the fibers from the
saw teeth. The increased velocity creates an air current that moves the lint across an
opening towards lint flue and on to a drum condenser, following air release against
the conducer screen. So called air blast gin for doffing, instead of brushes uses a
large air pipe with especially designed nozzles, which is kept close to the area where
the lint is removed. The air-flow through this pipe pierces the nozzles with velocity
sufficient to take the lint of the saw teeth.
Feeder rolls are controlled by disc grid and lever, which are operated by saw
gin fitter/ operator to control the feed of seed cotton to the gin stand. There are
generally 7 rows of holes in the disc grid. The extreme outer row is called no. 1.
Very efficient ginning and cleaning is obtained by using the feed no.2 if all settings
are correctly done.
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1. INTRODUCTION
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As pre- cleaner rolls there are generally four spiked rolls in one gin stand
fitted with a wire netting of 3 mesh x 12 gauge. These rolls clean leaf, dust and
motes.
Gin Saw: The gin saws are steel discs approx. 0.037 inches thick and provided with
about 7 teeth / inch. Generally the standard diameter of the saw is 12” or 16” and 264
to 282 teeth running speed from 650 to 700 revolution / min. For maximum
lint/saw/hour and for best results it should be curved. Figure 1.19 shows a typical
Gin saw blade used in industry. An ideal saw should have straight edges for leading
and with slightly curved “modified roach back” or trailing edge. The saw must be
sharp and the teeth undamaged. The pitch and the shape of the saw teeth are also
important in maintaining capacity and cotton quality. To ensure good ginning the
teeth must pass through the ribs at the proper angle. The point of tooth should enter
the ginning rib slightly ahead of the throat. If the saws are improperly filed or the
saw rib relationship is improperly adjusted so that the throat of the tooth enters the
rib ahead of the point, the resulting cutting action will reduce capacity and break
fibers causing choking at top of the ginning ribs. For current pitch, the leading edge
of the tooth should be parallel to the fan of the rib, or the point should slightly lead
the throat as it passes between the ribs. Saws should be examined frequently and bent
teeth should be straightened or even broken off so that lint will not remain hung in
them. When changing saws, it is best to keep saws of the same diameter on a
mandrel.
Figure 1.19. Gin saw blade (own photo)
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1. INTRODUCTION
Noorullah SOOMRO
Ginning ribs: Ginning ribs are important. The crucial aspect is its alignment in the
machine. They should be fitted in level with a space of 2 mm between each other as
it avoids cut seed coming in lint.
Hulling ribs: These ribs should also be fitted in level with ginning ribs and gap will
be about ½”. Seed cotton enters the gin stand huller ribs, hulls and sticks to fail out
the machine.
Hulling roll: This is also a type of spiked roll which feeds seed cotton to the ginning
saws through hulling ribs, the huller roll made of wood with spikes at 30° direction.
Nozzle: This is an air pressure pipe shaped an “egg” fitted behind the ginning saws,
when the ginning saws brings the lint with it after ginning, it is cleared from its tooth
by air pressure.
1.2.1.1.(2). Roller Gin System
Roller gin consists of a lather covered roller which is made to revolve in close
contact with a fixed metal blade Figure 1.20. The lint in the seed cotton sticks to the
lather roller (packing roll) and is pulled through the gap between the roller and blade,
which is too narrow for the seed to pass, the separation is helped by a moving knife
(Rotary knife) Figure 1.21. The lint is lifted off the roller and connected for onward
transmission to the balling press, while the seed follows its own channel.
Figure 1.20. Roller gin stands (Anonymous, 2006b)
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1. INTRODUCTION
Noorullah SOOMRO
Figure 1.21. Typical roller gin (Anonymous, 2001)
There are two types of roller gin:
•
Single standard width roller gin and
•
Double acting roller gin.
A single standard width roller gin stand turns out 50 lbs., of lint cotton per
hour, while a 90 saw gin stand yield more than 650-lbs. lint during the same period
of time. Double acting roller gin has two beater blades per roller. Roller gins are
considered better than saw gins for ginning cotton with long and middle staple
cotton.
The following are additional components of roller gin
Feeder: The cotton feed and rolls pressure automatically start when cotton is
available and stop when is not.
Spiked cleaning cylinders: These cylinders or rolls with spirally placed spikes clean
and spread the cotton uniformly as they pluck locks from the dense batt formed by
the feed rollers.
Brush doffing: A brush cylinder doffs the large saw cylinder and reclaimed saw
delivers the cotton directly to the ginning point.
Rotary knife or moving knife: This knife is adjusted to oscillate in strokes across
the contact edge of the stationary knife and the roller.
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1. INTRODUCTION
Noorullah SOOMRO
Stationary knife of fixed knife: This knife is set so that its edge is parallel to the
surface of the roller and can gin 60 to 80 kilograms of seed cotton per hour. A 90 saw
gin can, on the contrary gins 600 to 800 kilograms of seed cotton per hour. Roughly,
therefore one saw gin equals the output of eight roller gins. A part form capacity of
ginning there are other differences as well.
Packing of lather roll: This roll is covered with leather, a combination of canvas
and rubber, or some other covering that is firm and of such some texture that the
cotton lint will cling to it freely. The speed should be approximately as follow (Table
1.4)
Table 1.5. Rotational Speeds of Cylinders on Roller Gin
Rotating parts
Speed (rpm)
Packing roll
116
Rotary knife
447
Spiked cylinder
542
Saw cylinder
345
Reclaimed cylinder
306
Brush cylinder
1354
1.2.1.1.(3). Comparison of Roller Gin and Saw Gin
The two types of gin are really not competitive with one another. The roller
gin is used for ginning extra long staple cotton or the extremely short and rough
cotton. The saw gin is best suited to up land cottons with a staple of 7/8” – 1 – 3/16”.
In the very nature of things, the roller gin is a slow working machine
minimum of pre-cleaning equipment used and the lint therefore contains leaf and
trash. Apparently, a foreign matter adds to the ginning out-turn but this is actually a
disadvantage instead of advantage because foreign matter has to be got rid off in the
blow-room before cotton is spun. Cleaning of seed cotton before ginning is, in the
long run, cheaper than cleaning the lint in the blow- room. In the modern saw gins
there is a variety of pre-cleaning equipment for seed cotton and lint cleaners after
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1. INTRODUCTION
Noorullah SOOMRO
cleaning. Roller gin consists of feeder, spiked cleaning cylinder, brush daffier, feeder
apron, rotary knife (Moving knife) stationary knife (fixed knife), and lather roll
which is called packing roll.
1.2.1.1.(4). Post-ginning Operations
In order to get the maximum efficiency, the use of post cleaning machines is
also very important for good grade / quality required for cleaning of lint. It refers to
treatment of lint obtained at the gin-stand, intended to remove remaining minute
trash which escaped the pre-cleaning operation.
Lint cleaners: Lint cleaners were developed specifically to remove the foreign
matter i.e. Leaf particles, motes, grass and bark left in the lint by seed cotton cleaners
and extractors. Lint cleaners, in general are recommended only for gin which receive
trash or mechanically harvested cotton. These machine clean away about 98% of
trash from the lint which shows that its use is a must for effective cleaning of lint.
There are generally two types of lint cleaners:
§
Flow through (Air jet) and
§
Saw toothed lint cleaner.
Flow Through (Air-Jet) Lint Cleaner: The flow through air lint cleaner,
commercially known as Air jet, has no saw, brushes or moving parts. It is usually
installed immediately behind to the gin stand. Loose lint from the gin stand is blow
through a duct within chamber of the cleaner. Air and cotton moving through the
duct make an abrupt change in direction as they pass across the narrow trash ejection
slot. Foreign matter that is heavier than the cotton fibers and not too tightly held by
Fibers ejected through the slot by inertial force. Flow through air lint cleaners are
less effective in improving the grade of cotton than saw lint cleaners, but they also
remove less weight from the bale. Fiber length and strength are affected by the air
lint cleaner. This lint cleaner is not used commonly in our ginning industry.
Saw Toothed Lint Cleaner: This type of lint cleaner may now be seen in many
factories of Sindh & Punjab. This type of consists of saw toothed channels roll, a set
of feed works i.e. feed plate and feed rollers, a condenser screen drum and a series of
24
1. INTRODUCTION
Noorullah SOOMRO
grid bars. The basic principle is the “Combing Action”. Maximum lint cleaning
efficiency is directly related to the combining ratio, there is an optimum ratio for
each rate of lint feed to the lint cleaner. The automatic combing ratio and the batt
thickness control assure smoothers preparation and maximum diffusion of spots in
the cotton. The Fibers are better opened for more efficient and easier trash disposal at
the grid bars with minimum Fiber loss. In addition, an air stream effectively removes
fine trash and washes it away from the clean cotton.
Condenser: Condenser is that machine which besides cleaning leaf also condenses
the lint to bring it in shape a layer. There are 1 or 2 wire netting rolls in the machine,
when lint strikes against the wire netting rolls due to air pressure the leaf and dust are
sieved through it and thus the lint is cleaned more. Usually were netting wed in
condenser is 8 mesh x 19 gauge and there should be 8 holes in one inch.
Moisturizer: Before the cotton lint reaches tempers and press for baling, moisture is
added to prevent induced electrostatic charges.
Temper: The function of the temper is to loosely press the cotton lint in to the press
box as it received from the condenser.
Bale press: Packing is the final step in the processing of lint cotton at the gin.
(Figure 1.22) shows a bale press. There are four types of gin presses that produce
bales of differed size and densities flat, modified flat, gin standard and gin universal.
Cotton process of various styles is in use, such as single, double box down packing
and the double box up packing. The bale press consists of a ram (one or more), and a
hydraulic system. A pressure of about 22 ½ pounds per cubic feet is applied to the
bale. Flat bales are normally packed with six steel bands having strength of 3400
pounds. A bale is usually uniform in weight as possible 175 to 180 kg, and size 48”
height 18” width and 22” length. Figure 1.23 shows bale handling in a factory.
25
1. INTRODUCTION
Noorullah SOOMRO
Figure 1.22. Bale press (own photo)
Figure 1.23. Bale handling (own photo)
1.2.1.2. Ginning Industry of Pakistan
The factors affecting quality of cotton are trash contents present in the seed
cotton, moisture content of seed cotton during ginning operation, handling,
transportation and storage at the farm and at the ginning industry, mixing of varieties
and types of ginning machinery used for process.
At present there are around 1532 cotton ginning factories located all over
Pakistan most of them are unregistered by Pakistan Cotton Ginners Association
26
1. INTRODUCTION
Noorullah SOOMRO
(PCGA, 2010), equipped with 476 saw-gins of 80 saws, 4947 saw-gin of 90 saws,
793 saw-gins of 100 saws and 236 saw-gins of 120 feeder extractor cleaners, 620
openers, 120 lint cleaners. The total registered ginning factories are 631 (PCGA
2010). The total production capacity of ginning and pressing units in Pakistan on
80% efficiency is 2.5 million bales during 120 days at the rate of 179 268 bales per
day of 16-hours operation. There has been shift from roller-gin to saw-gins for the
reason that the capacity of one saw-gin in equal to the capacity of 20 rollers-gins.
Besides the roller-gin is labor intensive. For each roller-gin one labor is required.
Thus labor cost/bale on roller-gin is much higher than saw-ginned one. Presently
more than 90% of Pakistani cotton is ginned on saw-gins.
Most of the ginning factories in Pakistan are fitted with locally made
machinery. All these ginneries have saw-gin machines except very few units that
have roller-gin machines, imported from Turkey. The cotton industry in Pakistan is
operating at a very low level of efficiency specially the ginning sector needs more
attention because of the out dated machinery used for ginning. Figure 1.24 shows a
conventional gin saw blade used in local machinery. It is generally of 1950`s and is
very older design. Conventional gin saw blade made in Pakistan is with straight
teeth, sharp root, without heat treatment and defected blade of saw. There is no
standardized and proper use of ginning machinery resulting in wastage of fiber
leading to sub standard cotton lint production.
The main problem in ginning of cotton is that while separating lint from seed,
fibers are damaged due to use of inferior quality of local made gin-saw blade.
Another problem is that while removing lint from seed, the seed coat is also damaged
because of manual saw sharpening which causes diminished production of cotton oil
from the seed, severely affecting the cotton oil industry. Figure 1.25 demonstrates the
manual sharpening done by the local Ginners to sharpen the blade. Sharpening of
local gin saw is not feasible; it results in reduction of tooth size and saw size calling
for reduction in capacity of the gin. Hence, ginning sector continues to be the
weakest link in the cotton chain.
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1. INTRODUCTION
Noorullah SOOMRO
Figure 1.24. Local gin saw blade (own photo)
Figure 1.25. Manual saw sharpening operation (own drawing)
Cotton producing countries are seeking ways and means to boost their
exports, essentially to strengthen their economy. Pakistan is earning around 60
percent of its foreign exchange through export of cotton and cotton based products.
Although Pakistan is playing a key role in world cotton trade and production, it can
face problems, if proper attention towards quality improvement is not paid.
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2. PREVIOUS STUDIES
Noorullah SOOMRO
2. PREVIOUS STUDIES
The oldest mechanical device used to separate cotton from its seed was called
“churka gin”. It was in used in ancient China and India and still used in some remote
villages of Pakistan and India. This primitive gin made of two smooth rollers, one
steel roller on the top and other wooden roller on the bottom is driven by homemade
gears and a land crank to squeeze the seed from the fibers. The manually operated
churka gin could be operated by a man, but usually two men are required to produce
as much as 5lb of cotton fibers per day with the seeds damaged by crushing.
Bangladesh invented “Dacca Muslim” device ginned cotton fibers without damaging
the seed (Basu et al, 1999). This method involved the pre ginning practice such as the
contaminants like capsules and vegetation were cleaned and seperated manually. The
seed was latter combed by using fish bone to remove the residue cotton and by
manual movement of pins between the residue fibers.
In U.S, cotton was also ginned manually using hands. Since it was a timeconsuming process and limited the production capacity, therefore, this led to the
formation of the machine ginning. Eli Whitney in 1794 invented this gin
(Doraiswamy, 1993). His primitive model contained a spiked wooden roller, where
the spikes were bent and sharpened to form hooks. Seed cotton was placed in the
hopper in contact with the roller (Chaudhry, 2003). Due to the turning of the roller,
cotton passed between the iron strips and the spikes removed lint cotton. The
alignment was such that the spikes caught the cotton ball in its motion between the
strips and through the hopper, but it didn’t allow the passage of the seeds due to close
proximity. A roller brush rotating in the opposite brushed off the separated lint. The
present day saw gin is a modification in the Whitney’s model of Hodgen Holmes in
1796 (Anonymous, 2010b) in the form of circular saws substituted for the line of
hooks and open hopper bottom allowed uninterrupted operation. Today almost all the
cotton produced in the world is ginned mechanically (Chaudhry, 2000). Cotton gins
process was very similar as to saws used in Pakistan and cotton was obtained by
removing the fiber that grows out of the seed. Saw gin was the commonest type of
gin used in United States by 1830. The School of Agriculture of Auburn University
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2. PREVIOUS STUDIES
Noorullah SOOMRO
in Auburn, Alabama, has one of the oldest Gin Saws (Martha, 1999). The
Continental Gin Company, Prattville Alabama, made the gin in the 1880s (The
Merrill E. Pratt Cotton Gin, U.S. Patent No. 140,791, Awarded 15 July 1873, Figure
2.1). Auburn's gin has 40 saws that are akin to fine-toothed circular saws (Figure
2.2). They rotate in between metal strips known as the ribs. Together the whole
structure is known as the grate that holds back the seed cotton while the saws pull the
fiber through the spaces between strips. A brush moves to separate the fiber from the
teeth. The fibers are than collected on a condenser, which compact the fiber into
thick sheets. (Martha, 1999).
Figure 2.1. The Merrill E. Pratt cotton gin, general view (Anonymous, 2010b)
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2. PREVIOUS STUDIES
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Figure 2.2. The Merrill E. Pratt Cotton Gin view of gin saws (Anonymous, 2010b)
The initial research on design and development of gin-saw blade was done by
Mr. Thomes Cowell Craven (1873), in the State of Pennsylvania, inventing Cotton
Gin Saws; and declared that the following is a full, clear and exact description
thereof, reference being had to the accompanying drawing making part of
specification in which Figure 2.3 is a face view of blade. According to Craven it is
desirable that a greater stiffness and straightness be given to the blade that can be
obtained by the usual hammering process. Efforts have been made to flatten sawblades by pressing them between heated discs. Such saws require to be first heated
and darkened, after which they are placed between the heated dies and pressure
gradually applied, thus simultaneously drawing the temper, and to a certain extent
flattening the blade, after which the saw passes through the usual process of hand
hammering. They are then grounded and re-hammered. Saws so made are used for
sawing wood, metals, and stone, and are much thicker than cotton-gin saws. It has
been found in practice that “gauge twenty-one” is the best thickness for cotton gin
saws, and of that gage they are generally made. As a rule, the thinner the blades the
more they will “gin” in a given time. Cotton-gin saws are not “tempered”. Were they
heated they would “scale,” rendering grinding of them necessary, which is not
practicable on account of their thinness. Heretofore the saws of cotton gins, being, as
in necessary, very thin, would be crowded by the cotton unit they would strike or rub
against the rib or grating of the gin, causing a jamming, spinning process, upon the
cotton being ginned, and thus creating the “nip,” so troublesome to the cotton-
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2. PREVIOUS STUDIES
Noorullah SOOMRO
spinner, besides cutting the fiber and creating “fly.” His invention consists of
stiffening and straightening cotton-gin saws, by pressing and upsetting the saw-plate
into corrugations while the plate is in a cold state, by means of dies, this made of
treating the plate serving not only to stiffen and straighten it, but also to harden the
teeth. Figure 3.3 shows Letters Patents, Gin-Saw Blade No. 5,229 by T.C. CRAVEN
for cotton-gins, stiffened or straightened by corrugating. No significant modification
of gin saw blade has been done subsequently after the introduction by T.C
CRAVEN.
Figure 2.3. View of gin-saw blade No. 5,229 (Anonymous, 2007)
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3. OBJECTIVES OF THE RESEARCH
Noorullah SOOMRO
3. OBJECTIVES OF THE RESEARCH
The objectives research were to determine the optimal changes in the
modification of existing ginning process and its development that could potentially
produce the best turnout, production rate and fiber quality. The specific objectives
included:
§
Improving the operation of ginning process
§
Improving the quality of lint produced
§
Reducing energy consumption
§
Right humidification of seed cotton and lint
§
Latest research work carried out in universities integrated with ginning
industry
§
Intend to promote linkage of scientific research carried out by professors and
students in mainstream of industry by bringing awareness amongst the
ginners
§
Identification of weaknesses in gin-saw blades manufactured locally in
Pakistan
§
Influence of tooth profile of gin-saw blade on fibers
§
Identification of manufacturers and suppliers of gin-saw blades
§
Assistance to local manufacturing companies by transferring the technology
for manufacturing international quality gin-saw blades on a commercially
viable basis.
The need for this research was mandatory to enhance profits of growers and
ginners alike. The one area that needs to be optimized for maximum performance
was the ginning process, especially the gin-saw blade design. Optimization of the gin
saw blade is paramount to any ginning operation. Since the design and development
of gin-saw blade would be a new technology being introduced in order to maximize
its performance and influence the quality of the final product. Once such gin saw is
produced than work on the existing ginning process has to be done in order to
remove the flaws of the ginning process in general.
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3. OBJECTIVES OF THE RESEARCH
Noorullah SOOMRO
Development of gin saw blade will preserve as much of the original fiber
quality of the cotton as possible. Understanding how gin-saw blade affects the
quality of the fiber being ginned is paramount to proper operation of the gin stand.
Likewise, a gin saw blade that can minimize fiber damage and yet maintain
maximum production rate is an essential element in getting the producers' cotton
ginned in a timely manner without adversely impacting the quality of fiber being
produced. This research will provide information on how the gin-saw blade interacts
and how this interaction influences the quality of product being produced. This
information can be utilized to achieve the best possible fiber properties for a given
variety and/or customer's specific requirements.
The research will also provide a baseline of information on modification of
the existing ginning process with emphasis on the design and development of ginsaw blade, and how the gin saw blade parameters can be modified to produce the
most desirable product possible. The data will help ginning machinery manufactures,
gin-saw blade manufacturers and cotton ginners to understand how the optimal
settings and gin stands are impacted by the gin-saw blades. Likewise, the economic
impact of utilizing this technology will be evaluated, in order to assist decision
makers in determining whether or not the benefits gained from this technology are
economically viable for their operations.
Research objectives also included the need to find the optimal changes in
modification of the existing ginning process and in design of gin saw blade that will
result in maximum production rate, lint turnout, and best overall fiber properties.
Along with the assessment of the impact of the modification of ginning process on
the Cotton ginning industry in the long run.
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4. MATERIALS AND METHODS
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4. MATERIALS AND METHODS
4.1. Questionaire
The central purpose of questionnaire in ginning industry of Pakistan and
Turkey was to transfer know-how and technology from Turkey to Pakistani ginneries
in the context of:
§
To visit the existing ginneries, local manufacturers of ginning machinery and
manufactures of gin-saw blades
§
To observe and analyze the overall operation of ginning factories
§
To collect data via questionnaire given in Appendix
and identify the
problems in the ginning industry
§
To identify the weaknesses in gin-saw blades manufactured locally in
Pakistan and
§
Identification of manufacturers, suppliers of gin-saw blades
In this context, visits to various ginning factories in Pakistan and Turkey were
conducted. Observations were recorded to analyze the function, working, efficiency
and maintenance of each and every machine. The flow process was also evaluated
right from suction feed to the baling with focus on the effects of local gin-saw
especially in Pakistan on the ginning performance and lint quality.
During visits, meetings with various renowned local manufacturers of gin
machinery and replacement parts in Pakistan and Turkey were conducted. The
insight of manufacturer’s on the gin-saws was also taken into account. The most
significant of the visits was to M/S Abid Ismail Gin-Saw Manufactures at Karachi,
Pakistan. BALKAN Textile & Cotton Ginning Machinery Manufactures, Aydın,
Turkey and M/S Sumer Makina Fabrikası Ltd, Izmir-Turkey.
A Questionnaire was prepared and presented to the ginner and gin saw
manufacturers and the purpose of this questionnaire was mainly to:
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4. MATERIALS AND METHODS
Noorullah SOOMRO
§
identify the necessary modifications for optimal output in a ginning factory,
§
analyzing the effectiveness of an optimization operation for 1 unit and prove
commercial viability in terms of a reduction in energy expenditure,
§
putting in place the most effective means lowest at cost of managing and
monitoring moisture content after the arrival of seed cotton to the factory at
the bale compression stage; including demonstrating the advantages of
monitoring moisture content at different stages of the factory.
This task had to progress according to the following schedule:
§
visits to identify selected ginning factory at Sindh, Pakistan,
§
analyze the operation of the one selected ginning factory,
§
overall scheduling of activities,
§
prepare report, which would include necessary drawings and
recommendations for the modification of ginning factory.
Questionnaire and survey forms were prepared to focused on collecting data
regarding the type and use of Ginning machinery commonly used by Ginners in
Pakistan, their trends of using that machinery and the main problems they face while
ginning. These survey forms were taken to 16 ginning factories in Pakistan along
with various local gin-saw manufacturers. On the basis of the results the identified
problem with the Ginners were analyzed and a strategy was to be made to carry out
modification of the Gin Saws and on specifics of the Ginning Process.
Prospective experimental research was carried out after a cross sectional
survey on the Ginning Industry in Pakistan. Survey forms were designed and
distributed randomly in Ginning Industry and Gin Saw Manufacturers in the Sindh
and Punjab region of Pakistan where most of the cotton is sown. The forms aimed at
collecting key data during the ginning process from Ginners working in the Industry
and practices of the gin saw manufacturers in the development of the saw gins. It
included core questions such as the extent of fiber damage during Ginning and the
duration of usage of a gin saw. The questionnaire also targeted the view of the
Ginners regarding the improvement of the Ginning process and their general attitude
towards the betterment of lint cotton.
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Initial survey showed that during ginning of cotton; the ginning machines
cause damage to the cotton fiber as well as seed while separating lint from seed. This
is due to the imperfect gin-saw blade design, outdated local ginning machinery,
layout and systems that adversely affect fiber properties. Feedback revealed through
basis of questionnaire and survey forms was that the major obstacle for ginners was
the lack of new ginning machines and sub-standard gin-saw blade causing staple
damage of fiber as well as seed. As per revealed feedback, a research study for
modification of the existing ginning process with emphasis on the design and
development of gin saw blade was undertaken. Improving the gin-saw design was the
crux for the betterment of the ginning process in general and it would also lead to the
improvement of fiber quality consequently giving a better quality fabric.
4.2. The Status of Local Manufactured Gin-Saw Blade
In saw ginning machinery, one of the functional components (which need
periodic replacement depending on their quality and extent of use) is gin-saw blade.
Ginning saws in Pakistan mostly are locally produced. Local manufacturers use SAE
1020 steel and produce from cold rolled strips by cutting teeth with a high speed
teeth cutting device (15teeth/second). Later these teeth are sharpened before use. But
local manufacturers do not adopt the design standards in material selection and
manufacturing, the things are done by the stair of experience only. Moreover the
local gin-saw is of low quality steel (SAE 1020 untreated) and does not last for more
than one season (4-5 months).
Design of saw tooth has significance in the ginning performance and the lint
quality. The pitch and the shape of saw teeth can help in maintaining capacity and
cotton quality. To ensure ginning, the teeth must pass through the ribs at the proper
angle. The point of tooth should enter the rib slightly ahead of the throat (Figure 4.1).
If the saws are improperly filed or saw-rib relationship is improperly adjusted so that
throat of tooth enters the rib ahead of point, the resulting cutting action will reduce
the capacity and break fibers and may cause chocking at the top of the ribs. As a
37
4. MATERIALS AND METHODS
Noorullah SOOMRO
principle of cotton ginning, the fibers must be ginned from their very base on seed
cotton.
Figure 4.1. Pitch angle with tooth entering the throat (own photo)
The shape of teeth of local made gin-saw rubs off every season because of
low grade steel and results in wear due to ginning seed cotton with mixed foreign
impurities. Therefore it requires sharpening ever new season. This results in
reduction of tooth size and saw size calling for reduction in capacity of the gin. In
most of cotton ginneries in Pakistan, locally manufactured gin-saws are used which
are commercially available and do not seem to influence their overall ginning
performance. The gin-saws used in Pakistani ginneries have straight back teeth as
shown Figure 4.2.
Figure 4.2. Local gin-saw blade with straight teeth and throat angle of 29°
(own photo)
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4. MATERIALS AND METHODS
Noorullah SOOMRO
4.3. Design of New Gin Saw Blade
In this stage of the design process, the chosen concept was designed with all
the dimensions and specifications on a detailed drawing. According to T.C CRAVEN
1893 it was found in practice that “gauge twenty-one” is the best thickness for ginsaws (Mangialardi et al, 2000). As a rule, the thinner blades the more they will gin in
given time. The general design consideration regarding material selection for gin-saw
blade was the composition of the material. Selection of an appropriate material and
then converting it into a useful product with desired shape and properties is rather
complex process.
The important design consideration regarding material selection for gin-saw
blade was the composition of material. Nearly every engineering item goes though
the sequence of activities shown in Figure 4.3:
Figure 4.3. Formulation of scientific design and development of gin-saw blade
Initial study was performed to design and develop a prototype of the
scientific gin saw blade having its tooth angle decreased from 29° in order to get the
maximum fiber removed from the lint. For development of prototype of gin-saw
blades to prove the new technologies, the preparation of concept design/drawing was
important to look at conceptualizing designs and methods which can be used to
generate ideas. Design essentially is an exercise in problem solving. Typically, the
design of a new product consists of the stages shown in Figure 4.4.
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Figure 4.4. Stages for a new product design
The development of a new product also required the development of a
prototype to prove that new technologies work before committing resources to fullscale manufacture. It was necessary to produce prototypes to test ideas at this stage.
Key focus was also given to the fact the product designed can be manufactured in the
local industry.
Before producing the gin-saw blades the raw material was sent to Institute of
Material Science & Research of Pakistan Steel for its chemical analysis and
mechanical testing. The chemical analysis and mechanical testing result of report are
given in Table 4.1 and Table 4.2, respectively.
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Table 4.1. Chemical Test Report of Improved Gin-Saw Blade
S.No.
Code
%C
%Si
%Mn
%P
%S
%Ni
%Cr
01
ARS
0.62
0.38
0.78
0.02
0.03
0.04
0.02
02
S
0.76
0.32
0.81
0.02
0.006
0.04
0.12
Table 4.2. Mechanical Test Report of Improved Gin-Saw Blade
S.No.
Code
Yield/Proof Strength
Tensile
% Elong.
%Red.
01
ARS
592
Strength
986
10.4
26
02
S
1082
1175
8.4
21
4.4. Design Modification
A concept design & drawing with added value of engineering features for
manufacturing of prototype gin-saw blades with its tooth angle decreased from 29°
was done. The detailed drawing with all the dimensions/specifications, gauge and
appropriate material was provided to gin-saw manufacturer for its development as
per generated ideas. A total of 9 different Saws with tooth profiles ranging from 21°
to 30° were designed (Figure 4.5). 20 Nos. of Saw blades of each profile were
ordered to be made for the prototype testing. They were compared with standard
tooth profile of 29° with respective tooth designs, in accordance with specified
material of twenty one gauge SAE 1060 heat treated for better physical and
mechanical features.
In order to modify the tooth profile, the tooth angle has been changed.
Consequently, depth of tooth has increased since the back of the tooth was roached.
Also there was a 5% increase in the number of teeth per saw. Thus the modified saw
has 106 teeth compared with the 101 teeth of the local saw (Figure 4.6 and Figure
4.7).
Referring to the views below, tooth angle has decreased from 29º to 24º to
facilitate initiation and origination of throat curve right from the base of tooth angle.
It will also facilitate curving of back and throat and thus allow point of tooth pass
41
4. MATERIALS AND METHODS
Noorullah SOOMRO
through the ginning rib slightly ahead of throat so that fibers are ginned from very
base on cotton seed and that no or minimum fibrous residues on seed surface are left.
Figure 4.5 Scheme of comparison of standard saw with the modified designs.
New developed gin-saw blade has the following modifications (Figure 4.8):
•
Curved teeth
•
Curved root
•
Heat treatment
•
Self sharpening
•
Straight blade of saw
•
Free movement between rib
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Figure 4.6. Magnified profile view of local saw
[tooth angle = 29° degree, thickness= 0.92mm, pitch = 3.623mm, depth = 1.25mm]
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Figure 4.7. Modified gin-saw blade with curved teeth angle of 24 °
(tooth angle = 24°degree, thickness= 0.92mm, pitch = 3.297mm, depth = 3.46mm).
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4. MATERIALS AND METHODS
Noorullah SOOMRO
Figure 4.8. Modified gin-saw blade with curved teeth angle of 24 °
Gin rib
Gin saw
Brush doffer
Figure 4.9. The prototype gin stand. (Anonymous, 2009)
Comparative ginning of the gin-saws was conducted to study effects of
different designs of saws on ginning and lint quality. The initial optimal study was
performed using a variety of upland cotton Niab-78 (approx. 80% common cotton
variety in the region) that had been grown in Tandojam and harvested using female
hand pickers. Likewise, a similar comparative experiment using all the designs was
also conducted on MNH-93 (approx. 15% common cotton variety in the region) that
45
4. MATERIALS AND METHODS
Noorullah SOOMRO
is a cotton variety harvested in some parts of Punjab. 10lb of cotton sample was used
from both varieties for experiment.
Even though the initial study was a good
screening evaluation, it could be considered a "one-factor-at-a-time" approach. Since
each of these factors, and more, could have an impact in determining the ideal
operational situation for a certain varietal cotton grown in a certain area and
harvested a certain way, it is desirable to determine the operational condition.
Ginning Out Turn (GOT) was the primary parameter which was sought
during the research. GOT is important for Ginners because this signifies the amount
of cotton produced after their Ginning. The other variables that were measured
during the experiment included:
§
Fiber Length 2.5% S.L & 50% S.L
§
Uniformity Ratio
§
Presseley Strength (lbs/inch)
§
Short Fiber Content %
§
Maturity index %
§
Micronaire Value (Mic)
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5. RESULTS AND DISCUSSION
Noorullah SOOMRO
5. RESULTS AND DISCUSSION
5.1. Results of Questionnaire and Observations
Arrangements of the factories visited in frame of study were as follows:
§
A yard completely paved with bricks with seed cotton storage and drying
areas.
§
Ginning building
§
Administrative building
§
Scale bridge
§
Bale storage area (external)
§
Expeller press building with raw oil tank.
§
Oil cake storage building.
Seed Cotton Delivery: The seed cotton is delivered to the factory in jute bags of
about 40 kg (1 maund). Seed cotton is grouped by category (total 5) function of the
trash ratio and the immature (yellow) bolls inside. Majority of the seed cotton is
classified into 3rd category. Generally, seed cotton contains a lot vegetal fragments
like green bolls, burs, sticks, and leaves. Although seed cotton was handpicked but
seed cotton doesn’t look like manual picked cotton but rather like mechanical picked
cotton. In addition to that vegetal fragments, cotton contained foreign matter which
contaminated it, mainly fragments of polypropylene, clothes, string, jute, hair,
feather, thread, paper, and so on, that were accumulated along the transportation and
grouping of cotton at the level of trader’s middleman. Seed cotton, at the arrival in
the factory, was relatively damp (over 12% of moisture). The real observation, when
cotton was touched in the pile, was that it was much moist than the natural moisture
content; giving a feeling that water was sprinkled over it.
Drying: Seed cotton is dried on the bare ground in the sun, and then grouped in
homogenous pile corresponding to 100 bales production.
Preliminary Cleaning: Generally, the preliminary cleaning is made by hand and/or
mechanically and mainly allows homogenizing the seed cotton to produce regular
47
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
quality bales. This homogeneity is generally well appreciated by the spinners who
don’t have to modify their adjustments during the production.
Hand Cleaning: Some people have to clean, or rather to decontaminate, the seed
cotton in the yard of the factory before ginning, by extracting the non vegetal foreign
matter like jute bag strings, polypropylene thread, papers, and so an. This work is
made by a relatively important number of people in each factory visited (from 50 to
150 people).
Mechanical Cleaning: Some factories are equipped with flat or inclined cleaners in
the middle of the yard, that allow to proceed to a first cleaning and opening of the
seed cotton before ginning or drying. Diagrammatic representation of the ginning
equipment seen during the survey at factory is given in Fig. 5.1.
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5. RESULTS AND DISCUSSION
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Figure 5.1. Sketch of original ginnery
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5. RESULTS AND DISCUSSION
Noorullah SOOMRO
The factory visited in had practically the same line of equipment more or less
in other ginning factories of Pakistan, that is to say:
§
1 rock catcher
§
1 separator
§
1 inclined or flat cleaner (3 to 5 spike rollers)
§
1 stick machine or 2 FEC (average 2% of cases)
§
1 conveyor distributor
§
4 a 6 feeder cleaners
§
4 to 6 gin 80 saws (4%), 90 saws (65%), 100 saws (28%) or 120 saws (3%)
with air blast system.
§
1 lint cleaner (in average 10% of cases and generally by-passed)
§
1 condenser
§
1 lint slide with spraying humidification
§
1 press (1 or 2 rams)
§
1 hydraulic unit with “Triplex” pumps type with diving piston (exceptionally
hydraulic gear pump or axial pistons pump). Functioning with water and soap
or with hydraulic oil.
Energy & Electricity: The power is furnished by the national electrical network or
by generator. There is one each circuit breaker for each motor with start and stop
push buttons. For recent installations each distribution board is equipped with
ammeter. There is no automatic functioning; all the functions are done manually. For
the press there is an electric console with start and stop push buttons (tramper,
hydraulic unit, spraying pump) and two ammeters, one for the tramper motor and one
for pump motor. Depending of the amperage read the console operator stop the
tramper or activates the manual hydraulic valve for discharging the pump.
Bales and Wrapping: Bale weights about 170 kg for manual handling. The tie is in
majority made with steel strapping and sometime with quick link tie. The wrapping
covers more or less the bale depending of its destination (local or export). The
quality of the wrapping material is very heterogeneous, made with cotton more or
less closely woven or with jute material. The scaling of bale is done on a balance
with pan and counterweight.
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5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Operation: The ginning out turn is about 33 to 34%. The 90 saws gin capacity is 2
bales per hour. The ginning speed, which is called “Kilo per Saw per Hour” (KSH),
is about 3.8 (170kg x 2 bales/hour / 90 saws). Factory runs with two shifts of 8 to 10
hours corresponding to a production of 100 bales per day.
General checking: Table 5.1. lists an inventory of problems and observation met in
the factories. These problems are not listed in importance or priority order. The
existing ginneries were out dated and not in good condition but even though
improvement of the existing process can be done on them rather simply.
Table 5.1. Inventory of Problems Observed while Ginning
No.
1
2
3
4
Observations
Consequence and comments
A lot of bur and stick arrive in the gin
with seed cotton.
Saw works with those elements that imply :
- Breaking of the lint and increasing or neps ratio.
- Wear and breakage of saw teeth.
Some Rock Catchers are not adjustable.
Spike rollers of cleaners are worn,
cleared between spike and screen is not
respected. Screens are not always
straight.
Rollers are not parallel.
There is no documentation or technical
sheet or book, which indicate the good
length and clearance to respect.
5
Grid bars of stick machines are too
distant of the saw cylinder.
6
There is very few stick machine of
FEC.
7
There are not enough tools in the
factories.
8
Vacuum wheel droppers under
separator are not always airtight.
9
Some air leakage on pipe junctions.
10
The spike rollers of feeder cleaner were
often worn and the clearance between
spike and screen wasn’t adequate.
Screens weren’t always horizontal.
The adjustment allows to adjust the trash elimination.
The cleaning of seed cotton is very bad.
Functioning clearance are not respected.
Seed cotton goes through this machine but it is not sling
off against the grid bars. So, bur and stick stay in seed
cotton.
Stick machine and FEC are the only one machine
studied for eliminating burs and stick, and particularly
stick machine.
Staff can’t make regular intervention on machinery for
daily, weekly or monthly maintenance.
Some air must be sucked through the vacuum wheel and
so through the cleaners that may prevent or impede the
seed cotton is badly cleaning.
That allows losing some air, so energy, and installation
pollution.
Clearance between spike and screen is not respected, so
seed cotton is badly cleaned.
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5. RESULTS AND DISCUSSION
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Table 5.1 Inventory of Problems Observed while Ginning (continued)
11
Spike of applicator rollers in gin are in
a bad condition.
So there is a bad feeding of the gin and an irregular
density of ginning roller.
The density of the ginning roller is very high and that
imply:
- A very bad preparation of the lint, even at very low
ginning speed.
- A very bad extraction of the lint, so a very bad
uniformity ratio.
- An increase of the neps ratio.
12
Saw teeth are often worn, folded or
broken.
13
Saws are re-sharpened many time
That imply a diameter reducing and consequently:
- a low GOT.
- an increase of the neps ratio.
14
The angle of the teeth are not good after
manual sharpening, it must be parallel
to the rib at the ginning point.
A angle too vertical means:
- A breakage of the lint by cutting (scissors effect)
- A chocking of the lint in the top of the ginning ribs.
- A delinting effect which is confirmed by the high level
of short lint.
15
Some ribs have not the same level that
looks like “stairs”
This stair effect may perturb the ginning by:
- A different pressure on each side of the saw that means
a lateral wear of the ribs and a heating of the saw.
- A jamming and breakage of seeds.
16
Humidification by spraying system
Spraying has inconvenient to wet the lint and not to
humidify.
The moisture content is too variable and too
heterogeneous.
That imply generally some cardboard effect of the lint
(verified in a spinning mill)
17
Some factories are very clean.
A clean factory is the evidence of an orientation for
quality and maintenance policy.
Impossible to know functioning parameters and their
18
There is no production report
evolution (KSH. working time, energy consumption,
etc.)
No classifying of the lint by the ginner.
19
It’s the purchase that determines the
quality grade.
20
The ginner must know the quality and the technological
characteristic of the lint he produce (grade, length) to
know the ginning effect on the lint and to make the
corresponding corrections.
The personnel were not trained for
ginning.
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5. RESULTS AND DISCUSSION
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Existing ginning equipment manufactured in Pakistan is based on models
designed in the 1940’s. The original configurations of machines are not adapted to
seed cotton produce in Pakistan, because the seed cotton handpicked practically
looks like seed cotton picked with cotton pickers. To correctly gin the cotton, it must
absolutely be cleared of all the major impurities. Actual cleaners are not efficient
enough since the functioning of the clearance process was not up to the mark because
of the improper adjustment of the clearance of the roller’s spikes in the cleaner.
According to the survey and the questionnaire, the most encountered
problems in gin saws were fiber damage, change in curvature, and rusting (Figure
5.2). 79% of the ginners observed fiber damage while using the existing ginning
setup. It was a profound ratio in terms of performance and efficiency of the current
ginning setup. 50% of the ginners observed extensive saw tooth damage after ginning
which points out the fact that there needs to be improvement in the quality of the
saws (Figure 5.3).
Figure 5.2. Common problem is saws while ginning
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5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Figure 5.3. Frequency of saw tooth damage observed by ginners
The great majority (79%) of the ginners think that saw design would lead to
the enhancement of the fiber quality considered to be a significant indicator, and
hence the modification of the saw design was essential to address the problem
(Figure 5.4). 83% of the ginners wanted their ginning out turn (GOT) to increase and
felt that design modification of the current machinery could lead to an increase in
GOT (Figure 5.5).
Another common problem that the ginners faced was that the cotton fibers
were usually not completely removed from the seed during the ginning. This actually
lead not only to the loss of fibers but fiber damage due to the partial fiber removal
during ginning. This fiber damage increased the short fiber content and hence meager
quality cotton. It is of essential importance that a new concept design is built to
address these concerns of ginners for the betterment of the ginning industry which is
the backbone of textile industry.
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5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Figure 5.4. Opinion on gin saw design improvement lead to better quality fiber
Figure 5.5. Most important factor to ginners after ginning
5.2. Results of Prototype Testing
Comparative ginning of two gin-saws was conducted to study effects of
different designs of saws on ginning and lint quality. The experiments were
conducted with 10 replications on the lab gin stand for the tooth profiles (Figure 5.6).
Modified gin saw blades with modified angles were compared on the miniature gin
stand with the locally produced Gin Saw blade. The testing was carried out at
55
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Pakistan Atomic Energy Commission Agricultural Research Center, Tandojam.
Ginning Out Turn (GOT) was the primary parameter and other variables that were
measured during the experiment included. Table 5.2 and Table 5.3 showed that 10
replications were done between the angles ranging from 21 to 30º using Naib-78 and
MNH-93 cotton varieties. The mean readings showed the best results for GOT were
obtained at 24° when compared with other modified tooth profiles.
Figure 5.6. Lab gin stand with various gin saw blades
56
5. RESULTS AND DISCUSSION
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57
5. RESULTS AND DISCUSSION
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.
58
5. RESULTS AND DISCUSSION
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All the gin-saw types were subjected to comparative ginning testing on lab
gin stands to study effects of different designs of gin-saws on ginning and lint
quality. The data was collected with variables such as Fiber length, Uniformity ratio,
Presseley strength and Micronaire Value etc and assessed on SPSS v17.
GOT = Ginning out turn
A one way analysis of variance was done between groups to assess the impact
of angle of saw tooth on GOT (Table 5.2 and 5.3). Data was divided into 10 groups
according to the angle of the teeth on the saws:
(Group 1: µ1 = 21°, Group 2: µ2 = 22°, Group 3: µ3 = 23°, Group 4: µ4 = 24°,
Group 5: µ5 = 25°, Group 6: µ6 = 26°, Group 7: µ7 = 27°, Group 8: µ8 = 28°,
Group 9: µ9 = 29°, Group 10: µ10 = 30°)
Two hypotheses were made at 95% confidence level:
Null hypothesis
Ho : µ1 = µ2 = µ3 = µ4 = µ5 = µ6 = µ7 = µ8 = µ9 = µ10
Alternate hypothesis
Hα : µ1 ≠ µ2 ≠ µ3 ≠ µ4 ≠ µ5 ≠ µ6 ≠ µ7 ≠ µ8 ≠ µ9 ≠ µ10
CR (Critical Region)
if
F > Fα
F > 2.47
Than, Ho can be neglected. Hence alternate might be true. There was a
statistically significant difference at the p < 0.05 level, implying the tooth angle had
an effect on GOT values, resulting in different gin-out turns as the tooth angle varied
from 21 to 29 degrees.
59
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.2. Descriptive Statistical Analysis with Confidence Interval for Naib78
95% Confidence Interval
for Mean
Std.
N
Mean
Deviation
Upper
Std. Error Lower Bound
Bound
Minimum Maximum
21 degree
10 .302800
.0031415 .0009934
.300553
.305047
.2968
.3088
22 degree
10 .339100
.0058927 .0018634
.334885
.343315
.3301
.3449
23 degree
10 .346100
.0016035 .0005071
.344953
.347247
.3433
.3489
24 degree
10 .358220
.0062019 .0019612
.353783
.362657
.3446
.3675
25 degree
10 .346500
.0014765 .0004669
.345444
.347556
.3441
.3489
26 degree
10 .345000
.0016533 .0005228
.343817
.346183
.3419
.3481
27 degree
10 .343910
.0015373 .0004861
.342810
.345010
.3410
.3468
28 degree
10 .343100
.0018385 .0005814
.341785
.344415
.3401
.3461
29 degree
10 .341590
.0192579 .0060899
.327814
.355366
.3086
.3782
30 degree
10 .341500
.0016303 .0005155
.340334
.342666
.3390
.3440
100 .340782
.0151340 .0015134
.337779
.343785
.2968
.3782
Total
60
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.3. ANOVA with Degree of Freedom (df) for Naib-78
Sum of Squares
Between Groups
df
Mean Square
.018
9
.002
.004
90
.000
.023
99
F
43.626
Sig.
.000
(21°-30°)
Within Groups
(21°-30°)
Total
Tukey HSD test for post- Hoc comparison indicated that the mean score for
24° was (M=0.358, SD = 0.06), significantly different from all other groups (Table
5.4).
After 10 replications of readings, the best result for GOT was obtained at 24°
(Figure 5.7 and 5.8) and it was compared with 29° local saw for further experimental
testing (Table 5.5).
Figure 5.7. Mean GOT value analysis between 24° & 29°
61
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.4. Means for Groups in Homogeneous Subsets are Displayed
Subset for alpha = 0.05
Angle
N
1
2
3
21 degree
10
22 degree
10
.339100
30 degree
10
.341500
29 degree
10
.341590
28 degree
10
.343100
27 degree
10
.343910
26 degree
10
.345000
23 degree
10
.346100
25 degree
10
.346500
24 degree
10
Sig.
.302800
.358220
1.000
.330
Tukey HSDa
a. Uses Harmonic Mean Sample Size = 10.000.
The experimental results of ginned fibers are shown as under (Table 5.5):
A.
B.
C.
D.
Denotes the weight of seed cotton
Denotes the weight of lint
Denotes the weight of seeds
Denotes the weight of invisible
62
1.000
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.5. Experimental Testing Results for Modified Saw
RESULTS OF EXISTING SAW 29º
Replications
A
B
C
D
GOT %
1
3.53
1.05
2.4
0.08
32.01
2
3.41
0.91
2.26
0.12
33.72
3
3.51
1.01
2.31
0.2
34.19
4
3.53
1.05
2.26
0.22
35.98
5
3.5
1.02
2.42
0.19
30.86
6
3.53
1
2.3
0.23
34.84
7
3.57
1.14
2.22
0.27
37.82
8
3.54
1.03
2.32
0.21
34.46
9
3.51
1.05
2.31
0.22
34.19
10
3.49
1
2.32
0.18
33.52
Mean
3.51
1.03
2.31
0.19
34.16
RESULTS OF MODIFIED SAW 24 º
Replications
A
B
C
D
GOT %
1
3.53
0.92
2.31
0.08
34.56
2
3.41
0.91
2.2
0.12
35.48
3
3.51
1.2
2.22
0.2
36.75
4
3.53
1.04
2.23
0.22
35.69
5
3.5
1.05
2.23
0.19
36.29
6
3.53
1.14
2.25
0.23
35.98
7
3.57
1.07
2.29
0.27
36.35
8
3.54
1.1
2.32
0.21
35.76
9
3.51
1.09
2.31
0.22
34.19
10
3.49
1.09
2.23
0.18
36.10
Mean
3.51
1.09
2.23
0.18
35.82
63
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Figure 5.8. GOT at 24° and 29 º for Naib-78
Table 5.6 shows the group statistics comparison between 24° and 29° local and
modified saws respectively and it also shows the standard deviation from the mean
values.
Table 5.6. Group Statistics
GOT
Angle
N
Mean
Std. Deviation
Std. Error Mean
24 degree
10
.358220
.0062019
.0019612
29 degree
10
.341590
.0192579
.0060899
An Independent sample t-test (Table 5.7) was conducted to compare the GOT
between 24° and 29° saws. There was significant difference in scores for 24° (M=
0.358, SD=0.006) and 29° M=0.342, SD =0.019, t=(18)=2.599, p=0.018.
CI = Confidence Interval
64
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Cohen Classifies
small effect > 0.1
medium effect > 0.6
large effect > 0.14
The magnitude of the difference in means (mean difference=0.0166, 95% CI:
0.0032 – 0.0301) was large (eta squared = 0.273)
Table 5.7. Independent Samples t-Test
Levene's Test for Equality of
t-test for Equality of Means
Variances
95% Confidence Interval
of the Difference
Sig.
F
Sig. t
df
(2tailed)
GOT
Equal variances
assumed
Equal variances
not assumed
3.732 .069 2.599 18
Mean
Std. Error
Difference Difference
Lower
Upper
.018
.0166300 .0063979 .0031885 .0300715
2.599 10.847 .025
.0166300 .0063979 .0025241 .0307359
According to Cohen’s classification (1988, pp 284-7) the significance was a
large effect. The other measured lint characteristics of Naib-78 variety included Fiber
Length, Uniformity ratio, Presseley Strength and Short Fiber index (Table 5.8).
These characteristics were taken as main variables for comparative studies. The
Maturity Index and Micronaire Values were also measured.
65
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.8. Lint Characteristics
F/L(a/b)
U/R
P/S
W
SHF
M
Mi
Modified saw:
1.10/0.53
48.5
97.8
3.2
14.2
80.9
4.2
Local saw:
1.09/0.51
46.0
95.8
2.7
19.2
81.4
4.6
All the values were given as mean ±SD (n=10)
Lint Characteristics:
F/L = Fiber length; a= 2.5 % span
b= 50% span (inches)
U/R% = Uniformity Ratio
P/S = Preseley Strength (lbs/sq inch)
W% = Waste
SHF% = Short fiber content
M % Maturity
Mi = Micronaire
Fiber Length, Uniformity Ratio and Short fiber content showed statistically
significant difference after ANOVA for the Naib-78 variety (Table 5.9).
The One way ANOVA done for comparing the means of Ginning Our Turn
(Table 5.9) showed that there was a statistical significant between the mean GOT
values of Gin Saw groups. A total of 10 replications were done to measure the GOT
by the proto-type blades and each degree change in the tooth profile was taken as a
separate group.
66
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.9. ANOVA of Fiber Variables in Naib-78
Fiber Length
Sum of Squares df
Mean Square
Between (21°-30°)
,003
1
,003
Within (21°-30°)
,000
18
,000
Total
,003
19
UNIFORMITY
RATIO
Sum of Squares df
Mean Square
Between (21°-30°)
31,250
1
31,250
Within (21°-30°)
14,120
18
,784
Total
45,370
19
PRESSELEY
STRENGTH
Sum of Squares df
Mean Square
Between (21°-30°)
6,000
1
6,000
Within (21°-30°)
3,880
18
,970
Total
9,880
19
Short Fiber Content Sum of Squares df
Mean Square
Between (21°-30°)
37,500
1
37,500
Within (21°-30°)
4,500
18
1,125
42,000
19
Total
F
Sig.
262,850
F
,000
Sig.
39,837
F
,000
Sig.
6,186
F
,068
Sig.
33,333
Statistical Results for MNH-93 and its variables are given in Table 5.10.
67
,004
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.10. ANOVA for GOT in MNH-93 Variety
Degree
Sum of Squares
Between Groups 21-30°
Within Groups 21-30°
Total
df
Mean Square
123,186
9
8,981
90
132,168
99
F
13,687 137,158
Sig.
,000
,100
A further Post Hoc Homogenous Sub set Comparisons test was done along
with Tukey HSD Multiple Comparisons Table 5.11. The results from the test are
given in subsequent tables and the data revealed that the most significant difference
was between the modified 24° blade and the standard 29°.
The post Hoc test concludes that there was a significant difference in the
MNH 93 while measuring the GOT and there was statistically significant difference
between 24⁰ to 29⁰ blades (Table 5.12). ANOVA was performed for other Lint
Characteristics were; F/L = Fiber length; a= 2.5 % span, b= 50% span (inches),
U/R% = Uniformity Ratio, P/S = Presseley Strength (lbs/sq inch), W% = Waste,
SHF% = Short fiber content, M % Maturity, Mi = Micronaire shown in Table 5.13.
68
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.11. Tukey HSD Multiple Comparisons
(I) group
24°
29°
(J)
Mean
Std. Error
group Difference (I-J)
Sig.
95% Confidence Interval
Lower Bound
Upper Bound
21°
*
4,79200
,14127
,000
4,3336
5,2504
22°
2,43000*
,14127
,000
1,9716
2,8884
23°
1,79200*
,14127
,000
1,3336
2,2504
25°
2,67000*
,14127
,000
2,2116
3,1284
26°
1,73000*
,14127
,000
1,2716
2,1884
27°
1,91700*
,14127
,000
1,4586
2,3754
28°
2,30000*
,14127
,000
1,8416
2,7584
29°
2,11000*
,14127
,000
1,6516
2,5684
30°
2,23000*
,14127
,000
1,7716
2,6884
21°
2,68200*
,14127
,000
2,2236
3,1404
22°
,32000
,14127
,422
-,1384
,7784
23°
-,31800
,14127
,431
-,7764
,1404
24°
-2,11000*
,14127
,000
-2,5684
-1,6516
25°
,56000*
,14127
,005
,1016
1,0184
26°
-,38000
,14127
,194
-,8384
,0784
27°
-,19300
,14127
,934
-,6514
,2654
28°
,19000
,14127
,940
-,2684
,6484
30°
,12000
,14127
,997
-,3384
,5784
69
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.12. Post Hoc Homogenous Subset Comparisons
Subset for alpha = 0.05
group
N
1
2
3
4
5
6
7
21°
10
25°
10
33,2400
22°
10
33,4800
33,4800
28°
10
33,6100
33,6100
33,6100
30°
10
33,6800
33,6800
33,6800
33,6800
29°
10
33,8000
33,8000
33,8000
33,8000
27°
10
33,9930
33,9930
33,9930
23°
10
34,1180
34,1180
26°
10
24°
10
Sig.
31,1180
34,1800
35,910
1,000
,071
,422
,185
Means for groups in homogeneous subsets are displayed.
a. Uses Harmonic Mean Sample Size = 10,000.
70
,073
,194
1,000
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Table 5.13. ANOVA of Fiber Variables in MNH-93
FIBER LENGTH
Sum of Squares df
Mean Square
Between (21°-30°)
,004
1
,004
Within (21°-30°)
,000
18
,000
Total
,004
19
UNIFORMITY
RATIO
Sum of Squares df
Mean Square
Between (21°-30°)
29,260
1
29,260
Within (21°-30°)
11,230
18
,596
Total
40,490
19
PRESSELEY
STRENGTH
Sum of Squares df
Mean Square
Between (21°-30°)
4,900
1
4,900
Within (21°-30°)
3,120
18
,749
Total
8,020
19
SHORT FIBER
CONTENT
Sum of Squares df
Mean Square
Between (21°-30°)
41,100
1
41,100
Within (21°-30°)
6,000
18
1,675
47,100
19
Total
F
Sig.
322,720
F
,000
Sig.
36,990
F
,044
Sig.
5,638
F
,080
Sig.
35,750
,005
5.3. Discussion of Prototype Testing
There was a significant difference between other variables of the experiment.
Fiber length, Short Fiber Content and Uniformity Ratio all showed effects when the
tooth angle is changed while Ginning. As three major yarn characteristics count for
quality yarn, namely yarn strength, yarn appearance and spinning End breakage rate.
High strength, better performance and optimum end breakage while spinning may be
71
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
important to yarn through processing high quality cotton. High quality cotton must
possess good spinning characteristics namely; high length uniformity, high fiber
strength and low short fiber content.
Referring to the tabulated result above, fiber ginned by modified saw have
higher 2.5% SL and 50% SL; hence higher uniformity ratio (U.R %). By the virtue of
higher span length, these fibers have higher presseley strength (lb/in2) and lower
short fiber content due to higher length uniformity as compared to testing results of
fibers ginned by current saw.
Higher fiber strength and presseley strength added to strength of yarn. Higher
length uniformity (U.R %) results in reduced yarn unevenness (U %); whereas lower
short fiber content adds to reduced yarn unevenness (U %), reduced yarn hairiness
(H), reduced spinning end breakage rate and ultimately higher yarn appearance
grade.
By the way gin out turn (G.O.T %) by modified saw is a bit more than that by
current saw. By the virtue of modified tooth profile which brings about reduced
linters on cotton seed after ginning, whereas maturity index (M %) and micronaire
value (Mice) are not susceptible to tooth profile. The two vary with crop and
location.
The experimental and testing results are graphically produced in the
following graphs for each of the parameter (Figure 5.9). All the graphs show a clear
distinction of results based on the experimental data graphically reproduced below.
72
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Axis Title
Chart Title
120
100
80
60
40
20
0
Figure 5.9. Graphical results
Figure 5.10 shows the Ginning out turn % of Niab-78 at different tooth angle
of saw gin. At least ten (10) observations were taken for GOT% at all the angles
from 21 to 30 degrees. We can see that GOT % starts to increase as the higher tooth
angle was used and the optimum yield was at 24 degrees and then the trend was
descending up till 30 degrees tooth angle. The level of confidence for these values
was 95%.
Figure 5.11 shows the Uniformity Ratio % of Niab-78 at different tooth angle
of saw gin. At least ten (10) observations were taken for UR% at all the angles from
21 to 30 degrees. We can see that UR% starts to increase as the higher tooth angle
was used and the optimum yield was at 24 degrees and then the trend was descending
up till 30 degrees tooth angle. The level of confidence for these values was 95%.
73
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
35
GOT %
34,8
34,6
34,4
34,2
34
33,8
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.10. GOT % of Niab-78 at different tooth angle
Figure 5.11. UR % of Niab-78 at different tooth angles
Strength of Niab-78 at different tooth angle of saw gin are shown in Figure
5.12. At least ten (10) observations were taken for Strength at all the angles from 21
to 30 degrees. We can see that Strength starts to increase as the higher tooth angle
was used and the optimum yield was at 24 degrees and then the trend was descending
up till 30 degrees tooth angle. The level of confidence for these values was 95%.
74
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
49
Uniformity Ratio %
48
47
46
45
44
43
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.12. Strength of Niab-78 at different tooth angles
The Figure 5.13 shows the Short fiber content % of Niab-78 at different tooth
angle of saw gin. At least ten (10) observations were taken for Short fiber content %
at all the angles from 21 to 30 degrees. We can see that Short fiber content % starts
to increase as the higher tooth angle was used and the optimum yield was at 24
degrees and then the trend was descending up till 30 degrees tooth angle. The level
of confidence for these values was 95%.
Strength of MNH-93 at different tooth angle of saw gin are shown in Figure
5.16. At least ten (10) observations were taken for Strength at all the angles from 21
to 30 degrees. We can see that Strength starts to increase as the higher tooth angle
was used and the optimum yield was at 24 degrees and then the trend was descending
up till 30 degrees tooth angle. A similar consistent pattern of increase was seen in the
Ginning out turn and Uniformity ratio at 24 degrees during ginning of MNH-93 as
seen in Figure 5.14 and 5.15, respectively.
75
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Short fiber content %
25
20
15
10
5
0
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.13. Short fiber content of Niab-78 at different tooth angles
37
36
35
GOT %
34
33
32
31
30
29
28
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.14. GOT % Of MNH-93 at different tooth angles
76
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Uniformity Ratio %
49
48,5
48
47,5
47
46,5
46
45,5
45
44,5
44
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.15. UR % of MNH-93 at different tooth angles
Figure 5.17 shows the Short fiber content % of MNH-93 at different tooth
angle of saw gin. At least ten (10) observations were taken for Short fiber content %
at all the angles from 21 to 30 degrees. We can see that Short fiber content % starts
to increase as the higher tooth angle was used and the optimum yield was at 24
degrees and then the trend was descending up till 30 degrees tooth angle. The level
of confidence for these values was 95%.
Strength in lbs/inch
99
98
97
96
95
94
93
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.16. Strength of MNH-93 at different Tooth Angles
77
5. RESULTS AND DISCUSSION
Noorullah SOOMRO
Short fiber content %
25
20
15
10
5
0
21°
22°
23°
24°
25°
26°
27°
28°
29°
30°
Saw tooth angle
Figure 5.17. Short Fiber Content of MNH-93 at different tooth angles
78
6. CONCLUSION
Noorullah SOOMRO
6. CONCLUSION
The inherent physical characteristics of cotton fibers, which can satisfactorily
produce better quality yarn during yarn spinning, are susceptible to tooth profile of
gin saw used for cotton ginning. The current tooth design of Pakistan local made ginsaw is not favorable for the fibers to be ginned. Little modification in the tooth
profile by imparting roaches/curves on its back and throat may be taken to prevent
loss of GOT % (or ginning yield %) and fiber characteristics. Cotton ginning by
modified saw is practically possible and is wholly favorable to ginning even on bulk
level
6.1. Principle Sketch of Modification
In order to improve ginning process for obtaining better lint quality, the task
of the research work included not only on improvement of design of the saw gin
blades but also work on proceeding for the modification and improvement of the
functioning of one existing ginning factory (Figure 6.1). The aim is to give
recommendations on the basis of research after survey and analysis of Ginning
Industry. The recommendations are output and efficiency oriented goals coined for
the betterment of other ginning factories.
The modification in general includes changes in:
§
Design
§
Process
§
Ginning Techniques
§
Methodology
§
Energy efficiency
In this context, a concept drawing of a modified Ginnery is designed with necessary
modification and arrangements (Figure 6.2).
79
6. CONCLUSION
Noorullah SOOMRO
Figure 6.1. Sketch of original ginnery
Modifications are relatively simple to achieve and technically can be done to
the existing local machinery. New configuration is described below:
•
1 Rock Catcher (with adjustable deviation steel sheet)
•
1 Separator (unchanged)
•
1 Airline (inclined cleaner) (6 picked cylinders + grid rods)
•
1 Stick Machine (idem existing model)
•
1 conveyor distributor (unchanged)
•
1 Feeder Extractor Cleaner (FEC) above each gin.
•
Saw gin (unchanged)
•
1 Lint Cleaner with by-pass (unchanged)
•
1 Condenser (unchanged)
•
1 Lint Slide with spraying humidification
•
1 press + hydraulic unit (unchanged)
80
6. CONCLUSION
Noorullah SOOMRO
Figure 6.2. Sketch of modified ginnery
Rock Catcher: Rock catcher must be equipped with a deviation steel sheet and an
air reclaimer, all adjustable, to be adjusted to the trash ratio of seed cotton. Trash
output must be done with a vacuum wheel.
Separator: The vacuum wheel under separator must be air proof to avoid air suction.
Generally, separator processing rate is about 30 bales per hour for 6 feet large and 45
bales per hour for 8 feet large.
Inclined Cleaner: Existing cleaners must be modified or replaced by cleaners that
have more cylinders (total 6) and by replacing existing screen with grid rods
efficiency would be improved. They must be inclined about 300 for increasing their
efficiency (gravity effect). Inclined cleaner can be by-passed if the seed cotton is
originally clean enough.
Stick Machine: Existing stick machines are well adapted to the Pakistani’s seed
cotton. These machines are equipped with by-pass to take account of the cleanness of
seed cotton. There is a first input by-pass to be able to completely shut the machine if
81
6. CONCLUSION
Noorullah SOOMRO
the cotton is very clean and a second by-pass before the reclaimer cylinder to take
account of the level of cotton in the trash.
Feeder Extractor Cleaner: This extractor feeder, cleaner is the Lummus model
(1963). It is now used like inclined cleaner and like stick machine, originally, those
machines were placed above the gin to be used like a feeder of 80 or 90 Lummus saw
gins. It is this first function which is kept in the new disposal. This feeder allows to
open the seed cotton before ginning and to proceed to a last finer cleaning.
Ginning: For the gin machine, it is imperative to rebuild the applicator roller to have
a good feeding of the gin. The saw shaft rotating speed is 470 rpm. Saws and ribs
must match to the next specification.
Saws: The saws ensure the ginning and feeding function. The saw’s diameter must
be 12”. In case of diameter reduction, the feeding rate is reducing, so the ginning
flows. It has been demonstrate that reducing of the saws increase neps ratio in the
lint, and even for a little reducing.
The pitch and shape of the saw teeth are also important in maintaining
capacity and cotton quality. To ensure good ginning, the teeth must pass through the
ribs at the proper angle. The leading edge of the tooth should be parallel with the rib,
or the point of the tooth should enter the ginning rib slightly ahead of the throat. In
other case, if the throat of the tooth enters the ribs ahead of the point, the resulting
cutting action will reduce capacity and break lint and may cause chocking at the top
of the ginning ribs. Beyond a certain angle, saws perform like delinting saws and pull
up a lot of very short lint (linter) from the seed. Quantity of lint that a saw can
remove depends of cotton cleanness and of metallurgical properties of the saws.
Rough cottons causes more wear than clean cotton, regardless of the type of steel
used.
Ginning Ribs: The ginning ribs must be correctly mounted. For that, it is essential to
group them per lot with same shape and dimension before mounting. That allows
avoiding “stairs” mounting prejudicial to a good ginning. So, if ribs are all identical,
it is possible to adjust correctly the saw shaft on all the length. Generally, the rib’s
live is twice than the saws. It must be notice that, very often, ribs are worn in the first
days of working because of bad Saws Mounting.
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6. CONCLUSION
Noorullah SOOMRO
Drying and Humidification: Drying and humidification are important factors in
ginning process. Actual drying is made under the sun, so the cost is very low.
Moreover, the fact to mix the cotton allows obtaining homogeneous lot of lint that is
good which appreciated by the spinners.
Pneumatic Handling System: Cotton gins use enormous quantities of air for
pneumatic conveying. The air systems consume generally over half of the total
power required. So it is very important to maximize the efficiency of pneumatic
systems. To have some idea of the dimensions of the piping are give below with
some basic information.
Some useful rules to follow are:
§
Make piping as simple and direct as possible, eliminating unnecessary elbows
and valves
§
Keep pipe joints as airtight and rigid as possible to minimize air leakage
§
To determine the fan, we must know the total air quantity and the total
pressure in the circuit that depend of the air friction of the pipe, the length of
pipe, the number of elbows, the quantity of air loss in the piping and the
machines. So, with different characteristics of the fan (functioning curves), it
is possible to choose the good dimension fan and to know its power and
rotating speed.
Setup of Modification: The proposed modifications must be realized by ginners
who have their actual dynamism and goodwill to make evolved the ginning in
Pakistan. Those modifications must be realized in association with qualified ginning
engineer. Who can technically explain that must be done and why it must be done.
Those modifications will be checked by ginning engineer during realization, before
running of the new season. To verify that modification is in conformity with the
recommendation set eventually to give complementary information or explanations.
Reducing Energy Consumption: Now, energy consumption is relatively important
by the fact that unit flow of each machine is very low according to the installed
power. The consumption of a machine may be, in first approximation, assimilated at
the sum of a without product consumption (only the machine) and a product
consumption. The consumption without product is fixed and with product is
83
6. CONCLUSION
Noorullah SOOMRO
proportional to the flow of cotton. So, the unit energy consumption decreases
according to the flow of cotton. The reducing of energy consumption will be viewed
only when the asked modifications will be done and that the running power will be
well known. The actual modifications needing and increasing of the machines, the
power will automatically increase. On the other hand, the quality of cotton at ginning
level will increase the processing rate. Global balance of consumption will be done
consequently.
6.2. Recommendations
The lint of Pakistan is well known for its strength, but its value is decreased
mainly because of poor harvesting practices. The spinners have made important
effort to invest in cleaning equipment to compensate those inconveniences. So, the
spinners have to pay differential cost for better grade cotton.
The bad quality of the lint implies to poor export in spite of removing of
precedent imposed quotas. An increasing of lint quality will allow to stimulate
exportations, enhanced the value of lint on a base of international criteria for grade
and length. This increased value will incite automatically the spinners to bring into
alignment the export price.
It may be mentioned that if the seed cotton is of good quality, even the
adoption of better ginning practices like the use of raised plat-forms for seed cotton
and lint bales with proper arrangement, yellow picking, pronging and spreading of
seed cotton, control on application of moisture to lint before pressing, removal of
pieces of twine and dirty patches of lint before pressing, proper setting, operation at
right spread and timely service, repairs and cleaning of ginning machinery etc. can
yield satisfactory results. However, if the people concerned with the ginning industry
want to produce really high grade cotton, they will have to follow the detailed
guidelines given in this thesis.
Realization of the modernization program of the ginning factories can’t be
done without an appropriate and adapted assistance of the actual personnel. A
84
6. CONCLUSION
Noorullah SOOMRO
training program must be started as soon as possible in order that ginning technicians
will be able to correctly operate the machines.
For knowledge of seed cotton and lint, cotton research institutes, cotton
standard institute are very well adapted and will give all the necessary training.
While training one or more ginning factory and spinning mill visits is essential to
know the needs and problems of spinners. Those training will be done on a very
short time and knowledge to assimilates is really important, so it will be certainly
necessary to prefect this knowledge with a complementary training program done on
several years according to the needs. It seems essential that future specialists to be
trained in ginning field, can visit some existent installations in other country for good
understanding and apprehension of ginning improvement. For future works, the
suggested saw gin blades on full scale can be manufactured commercially in Pakistan
with no premium in price on long term basis.
85
6. CONCLUSION
Noorullah SOOMRO
86
REFERENCES
ANTHONY, W. STANLEY, and MAYFIELD W.D. 1984. Influence of bale volume
on ginning GA, January 8-12, pp. 264-267, National Cotton Council,
Memphis, TN.
ANONYMOUS 1999. Ginning and Processing Research to Enhance Quality,
Profitability,
and
Textile
Utility
of
Western
Cottons
http://www.ars.usda.gov/research/projects/projects.htm?ACCN_NO=408
961
. 2001. USDA Cotton Handbook ERS 1994. (http://books.google.com/
Cotton+Ginners+Handbook+number+503&source=bl&ots=Xl0dsVwILi
&sig=EvneV6cKSoLieje2iZQWaJig6N0&hl)
. 2002. CEC Handbook White Gold of Pakistan 1995, CEC library.
_______. 2006a. Impact of Cotton Gin Machinery Sequences on Fiber Value and
Quality. http://asae.frymulti.com/abstract.asp?aid=25659&t=1
_______. 2006b. Sumer Makina Izmir Catalog for Roller Gin Stand.
. 2007. 100 Years of Cotton Production, Harvesting, and Ginning Systems
Engineering. (http://.asae.frymulti.com/abstract.asp?aid=25234&t=1)
_______. 2009. LUMMUS CORPORATION. Prototype Lab Gin Stand Design
Catalog. Crossroads Business Center · One Lummus Drive · Savannah,
Georgia 31407 USA
_______. 2010a. USDA COTTON HANDBOOK
http://books.google.com/books?id=XxSI5iP_f5AC&pg=PA171&lpg=PA
171&dq=Cotton+Ginners+Handbook+number+503&
_______. 2010b. Martha, P. on Hodgen Holmes 1796 Gin saw. Internet source
http://www.auburn.edu/~lakwean/gins/auprattgin.html (11/27/10)
_______. 2010c. News Paper source. Daily Times, Pakistan. Sunday, April 11,
2010.
APTMA. 2008. ALL PAKISTAN TEXTILE MILLS ASSOCIATION ‘Year
statistics for Texile Mills in Pakistan.’ PAKISTAN.
87
BASRA, A., S. 1999. Cotton Fibers Quality Improvement, and Textile Processing,
an imprint of The Haworth Press, Inc., 10 Alice Street, Binghamton, NY
13904-1580, USA.
BASU, A. K., IYER, K. R. Krishna NARAYANAN, S. S. and RAJENDRAN, T. P.
1999. “Cotton History”, INDIA.
CHAUDHRY, R.M. 2000. New Frontiers Cotton Production, ICAC Washington
D.C, USA. 106, pp.14-22.
_______. 1991 revised 2003. THE ICAC RECORDER, Technical Information
Section, International Cotton Advisory Committee, 1629 K Street, Suit
702, Washington, D.C 20006, USA
DORAISWAMY, I. 1993 "COTTON GINNING", Textile Progress, The Textile
Institute, ISBN: 9781870812481 UK.
ERS, 2009. Economic Research Service, World Agriculture Outlook source USDA
(United States Department of Agriculture) USA.
GULYASAR L. 2000a. Technological Report of Turkish Cotton Varieties. The InterRegional Co-operative Research Network on Cotton 20-24 September
2000. Adana, Turkey.
_______. 2000b. A Research on the Co-Relation between Fiber and Yarn Properties
of Cotton. The Inter-Regional Co-operative Research Network on Cotton
20-24 September 2000. Adana, Turkey.
ICAC, 2010. (International Cotton Advisory Committee) report International Cotton
Advisory Committee, 1629 K Street Suit 702, Washington D.C 20006,
USA.
MANGIALARDI, G.J.Jr. and ANTHONY W.S. 2000. Gin Saw Developments
Published by The National Cotton Ginners Association Memphis, TN,
USA 2000
MARTHA P., 1999 College of Agriculture, Constituency Affairs, 107 Comer Hall,
Auburn University, AL 36849; 334 844 3198
PCCC,
1988. Pakistan Central Cotton Committee. Cotton in Pakistan, Pakistan
Central Cotton Committee, Minister of Food and Agriculture,
88
Government of Pakistan, Moulvi Tamizuddin Khan Road, Karachi,
Pakistan (Urdu).
_______. 1999. Cotton in Pakistan, Government of Pakistan, Moulvi Tamizuddin
Khan Road, Karachi, Pakistan.
PCGA. 1999. Pakistan Cotton Ginners’ Association. Cotton Facts and Figures
www.pcga.org PCGA House, MDA Road Multan
. 2010. Pakistan Cotton Ginners’ Association Consolidated Statement of
Cotton Arrivals in Factories of Pakistan PCGA House, MDA Road
Multan
SEAGULL, ROBERT and ALSPAUGH, P., 2001. Cotton Fiber Development and
Processing An Illustrated Overview, International Textile Center, Texas
Tech University, Lubbock, Texas, USA.
USDA. 1964. U.S. Department of Agriculture. Handbook for cotton ginners. U.S.
Department of Agriculture, Agricultural Handbook 260, 121 pp.
_______. 1994. U.S. Department of Agriculture. Cotton Ginners Handbook, Title:
aS501.2.M54-1992 Number 503.
_______. 2001. Economic Research Services, Agricultural Outlook Board. Manual
of Cotton Ginning Number 504. Texas US.
89
90
DR. NOORULLAH SOOMRO
Flat 3, L.S.H Mahal, near Rimpa Plaza, M.A Jinnah Road, Karachi Pakistan.
e-mail: [email protected]
+92 333 2150840
PhD Çukurova University, Adana, Turkey.
Post Graduation (Textile) Dong Hua University, Shanghai, China.
MBA IBA Sindh University, Jamshoro, Pakistan.
B.E (Mechanical) NED University of Engineering & Technology,
Karachi, Pakistan.
WORK HISTORY
2003 to date. Assistant Professor
Mehran University of Engineering & Technology,
Jamshoro, Sindh, Pakistan.
1997-03
Principal Laboratories Engineer
NED University of Engineering & Technology, Karachi,
Pakistan.
1987-97
Cotton Ginning Engineer/ Manager (Training)
Cotton Export Corporation of Pakistan, Ministry of
Commerce, Finance & Trade Centre, Karachi. Pakistan.
PROFESSIONAL ACCOMPLISHMENTS
Engaged to impart lectures on “Textile Production Management”,
“Basic Textile Engineering”, and conduction of Subject Practical
Training in Mehran University.
91
Collaborated with NED University in setting up the biggest
mechanized Textile Engineering Laboratory and continually generated
technical solutions; also looked after the academic and administrative
affairs of the Textile Engineering Department.
Successfully assisted CEC in determining the areas in field of Ginning
Industry where improvement and balancing was required and also
trained personnel employed in Ginning Industry under auspices of
CEC Institute of Ginning.
Helped AACM Australian Consulting Team for setting up of a fullfledged Institute of Ginning under ADB (Asian Development Bank) as
Counterpart Training Specialist. (23 August,1993- 07 December,1994)
Engaged as Ginning Engineer/Manager ADB-FAO to assist Cotton
Development Project for Ginning Industry Survey and Modernization
of Ginneries. (21 October,1992 - 31 May,1993)
Ø Foreign Training / Study Tours & Technical Visits
International Training Course & Workshop on Chinese Textile
Machinery and Technology at Wuxi & Shanghai, China. September 16
~ 21, 2001.
Textile Products Familiarization Course at SDL International Ltd.
between the 24th and 26th of August 2000, Stockport, UK.
Undertaken study tour as Technical Member of an Official Delegation
to Egypt, Turkey, England, Germany and Switzerland for experience of
Cotton Ginning, Grading, Classification and Testing Technologies. 25
August - 20 September, 1991.
Technical Visit to the Ginning Factories & Textile Mills in the region
including Adana, Turkey. Organized by the Department of Agricultural
Machinery, Faculty of Agriculture, University of Çukurova, Adana,
Turkey. 06 - 21 March, 1995.
Cotton Processing Industry of Turkmenistan to study the process being
used in CIS ginneries. 22 March – 24 April, 1995.
A Nine Month In-plant Vocational Training in Turbine & Turbo-Blower
from Donetsk-Ukraine (Former USSR) March – December,1977.
92
ASSOCIATION WITH PROFESSIONAL SOCIETIES
•
•
•
•
Member Advisory Board Kohan Middle East Textile Journal (IRAN)
Life Member of Pakistan Engineering Council (PEC)
Member Institution Engineering of Pakistan (IEP)
Member Fiber Society (USA)
PUBLICATIONS
Research paper on “Influence of Contaminated Cotton on Yarn of
Manufacturing” presented at The Fiber Society Spring 2010
International Conference on Fibrous Materials, scheduled to be held
on 12-14 May 2010. Bursa, Turkey.
Research paper on “Influence of tooth profile of gin-saw blade on
the fiber characteristics” published at 10th International Congress on
Mechanization and Energy in Agriculture, 14-17 October, 2008,
Antalya, Turkey.
Have honor to prepare a book on “Cotton Ginning and Machinery for
Better Ginning Operations” in year, 2000.
KNOWLEDEGE OF LANGUAGES
English
Urdu
Sindhi
Turkish
Russian
(Excellent)
(Excellent)
(Mother tongue)
(Excellent)
(Fair)
REFRENCES
Mr. Illahi Bukhsh Soomro
Prof. Dr. Serdar ÖZTEKİN
Ex. Speaker
National Assembly of Pakistan
Phone # 0092 213 5687335
Department of Agricultural Machinery,
Çukurova University, Adana-Turkey.
Cell # 0090 533 725 38 38
93
94
APPENDIX
QUESTIONAIRE
(By Noorullah Soomro)
(GIINNG INDUSTRY SURVEY)
Name of Factory:
__________________________
Location:
__________________________
No. of Personnel Employed:
____________________
Series of Pre Ginning Machines: ___________________
No. Saw Gin Stands:
___________________________
Series of Post Ginning Machines: __________________
Production of Bales per season: ___________________
Q1. Which saws do you use in your factory?
a. Local
b. Imported
(if Imported than please specify country) _______________
Both
Q2. In which parts of Pakistan does the local manufacturing of Gin Saws exist?
a. Melsi
b. Vehari
c. Arifwala
d. Karachi
e. Burewala
f. Multan
Q.3 Which size of Saws do you use?
a. 12”
b. 16”
c. 18”
Q4. How many saws do you use per Gin Stand?
a.90
b.100
c.120
95
Q5. What is the frequency of Saw change in your Gin Stand?
a. After Ginning 10,000 Bales.
b. After Ginning 10,000 Bales.
c. After Ginning 10,000 Bales.
d. Other Please specify ____________
Q6. Which is the most common problem you observe with the use of saws while
ginning?
a. Fiber damage
b. Change is saw curvature
c. Rusting
d. Other please Specify _____________
Q7. How frequent do you observe Saw tooth damage?
a. Very frequent
b. Frequent
c. Occasional
Q8. What do you do when the tooth gets blunt?
a. Discard it
b. Sharp it manually
c. Take no notice
d. Don’t know
Q9. Do you observe seed damage while ginning?
a. Yes
If yes than Please tick the extent of damage
Extensive
Moderate
Slight
b. No
Q 10. Do you think if the gin saw design is improved you can get better fiber
quality?
a. Yes
b. No
96
Q 11. What is the most important factor to you after Ginning of cotton?
a. Ginning Out Turn
b. Fiber Length
Other Please specify ____________
97