The Jute Industry: From Seed to Finished Cloth
by
T. Woodhouse and P. Kilgour
Part 1 out of 2
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THE JUTE INDUSTRY
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(Book List)]
PITMAN'S COMMON COMMODITIES AND INDUSTRIES SERIES
THE JUTE INDUSTRY
FROM SEED TO FINISHED CLOTH
BY T. WOODHOUSE
HEAD OF THE WEAVING AND DESIGNING DEPARTMENT, DUNDEE
TECHNICAL COLLEGE AND SCHOOL OF ART
FORMERLY MANAGER MESSRS. WALTON & CO., LINEN MANUFACTURERS,
BLEACHERS AND FINISHERS, KNARESBOROUGH.
AUTHOR OF "THE FINISHING OF JUTE AND LINEN FABRICS,"
"HEALDS AND REEDS FOR WEAVING: SETTS AND PORTERS,"
JOINT AUTHOR OF
"JUTE AND LINEN WEAVING MECHANISM,"
"TEXTILE DESIGN: PURE AND APPLIED,"
"JUTE AND JUTE SPINNING,"
"CORDAGE AND CORDAGE HEMP AND FIBRES,"
"TEXTILE MATHEMATICS,"
"TEXTILE DRAWING," ETC.,
AND
P. KILGOUR
HEAD OF THE SPINNING DEPARTMENT,
DUNDEE TECHNICAL COLLEGE AND SCHOOL OF ART
FORMERLY MANAGER BELFAST ROPE WORKS.
JOINT AUTHOR OF
"JUTE AND JUTE SPINNING,"
"CORDAGE AND CORDAGE HEMP AND FIBRES," ETC.
1921
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PREFACE
The sub-title of this little volume indicates that practically
all the processes involved in the cultivation of jute plants,
the extraction of the fibre, and the transformation of the fibre
into useful commodities, have been considered. In addition, every
important branch of this wide industry is liberally illustrated,
and the description, although not severely technical, is
sufficiently so to enable students, or those with no previous
knowledge of the subject, to follow the operations intelligently,
and to become more or less acquainted with the general routine
of jute manufacture. As a matter of fact, the work forms a medium
of study for textile students, and a suitable introduction to the
more detailed literature by the authors on these textile subjects.
T. WOODHOUSE.
P. KILGOUR.
March, 1921.
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CONTENTS
CHAP.
PREFACE
I. INTRODUCTORY
II. CULTIVATION
III. RETTING
IV. ASSORTING AND BALING JUTE FIBRE.
V. MILL OPERATIONS
VI. BATCHING
VII. CARDING
VIII. DRAWING AND DRAWING FRAMES
IX. THE ROVING FRAME
X. SPINNING
XI. TWISTING AND REELING.
XII. WINDING: ROLLS AND COPS
XIII. WARPING, BEAMING AND DRESSING.
XIV. TYING-ON, DRAWING-IN AND WEAVING
XV. FINISHING
INDEX
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ILLUSTRATIONS
FIG.
1. NATIVES PLOUGHING THE GROUND
2. BREAKING UP THE SOIL OR "LADDERING"
3. PHOTOMICROGRAPHS OF CROSS-SECTIONS OF A JUTE PLANT
4. NATIVES CARRYING SMALL BALES OF JUTE FIBRE
FROM BOAT TO PRESS-HOUSE
5. NATIVES BAILING JUTE FIBRE IN A
WATSON-FAWCETT CYCLONE PRESS
6. VESSEL LADEN WITH JUTE AT QUAY-SIDE
ADJOINING JUTE SEEDS IN DUNDEE HARBOUR
7. HARBOUR PORTERS REMOVING BALES OF JUTE
FROM VESSEL SHOWN IN FIG. 6
8. BALE OPENER (MESSRS. URQUHART, LINDSAY & CO., LTD.)
9. BALE OPENER (MESSRS. CHARLES PARKER, SONS & CO., LTD)
10. HAND-BATCHING DEPARTMENT WITH UNPREPARED
AND PREPARED FIBRE
11. SOFTENING MACHINE WITHOUT BATCHING APPARATUS
12. BATCHING APPARATUS
13. SOFTENING MACHINE WITH BATCHING APPARATUS
14. MODERN BREAKER CARD
15. FINISHER CARD WITH DRAWING HEAD
16. WASTE TEAZER
17. PUSH-BAR DRAWING FRAME
18. ROVING FRAME
19. FAIRBAIRN'S ROVING FRAME IN WORK
20. AN INDIAN SPINNING FLAT
21. A LINE OF SPINNING FRAMES
22. BOBBIN WINDING MACHINE (FROM HANKS)
23. ROLL WINDER FOR LARGE ROLLS
24. ROLL WINDING MACHINE (FROM HANKS)
25. COP WINDING MACHINE (MESSRS. DOUGLAS FRASER & SONS, LTD.)
26. COP WINDING MACHINE (MESSRS URQUHART, LINDSAY & CO., LTD.)
27. A ROW OF MODERN WARPING MILLS.
28. POWER CHAIN OR WARP LINKING MACHINE
29. WINDING-ON OR DRY BEAMING MACHINE
30. A MODERN YARN--DRESSING MACHINE WITH SIX STEAM-HEATED CYLINDERS
31. DRESSING MACHINE FOR PREPARING TWO WARPS SIMULTANEOUSLY
32, SIX DISTINCT KINDS OF TYPICAL JUTE FABRICS
33. POINT-PAPER DESIGNS SHOWING WEAVES FOR VARIOUS CLOTHS.
34. DIAGRAMMATIC VIEWS OF THE STRUCTURE OF PLAIN CLOTH
35. WEAVING SHED WITH BELT-DRIVEN LOOMS.
36. LOOMS DRIVEN WITH INDIVIDUAL MOTORS
37. BOBBY LOOM
38. BRUSSELS AND WILTON CARPET LOOM
39. THE OLD WAY
40. THE NEW WAY
41. CROPPING MACHINE AT WORK
42. DOUBLE CROPPING MACHINE
43. DAMPING MACHINE
44. CALENDER
45. HYDRAULIC MANGLE
46. FOLDING, LAPPING OR PLEATING MACHINE
47. CRISPING, CREASING OR RIGGING MACHINE
48, SEMI-MECHANICAL BAG OR SACK CUTTING MACHINE
49. OVERHEAD (LAING) SACK SEWING MACHINE.
50. SACK PRINTING MACHINE.
THE JUTE INDUSTRY
FROM SEED TO FINISHED CLOTH
CHAPTER I. INTRODUCTORY
The five main fibres used for ordinary textile purposes are cotton,
flax, jute, silk and wool; in this group jute has been considered in
general as being of the least value, not only in regard to price,
but also in regard to utility. It is only under phenomenal
conditions which arise from a great upheaval such as that which took
place during the world's great war from 1914 onwards that, from a
commercial point of view, the extreme importance of the jute fibre
and its products are fully realized. Millions of sand bags were made
from the year 1914 to the year 1918 solely for military purposes,
while huge quantities of jute cloth were utilized as the covering
material for food stuffs of various kinds, thus liberating the other
textile fibres and cloth for equally important purposes. It is on
record that in one short period of fourteen days, 150,000,000
sand-bags were collected, packed and despatched from Dundee to be
used as protective elements in various ways and seats of conflict.
A glance into the records of the textile industries will reveal the
fact that the jute fibre was practically unknown in these islands a
hundred years ago. Unsuccessful attempts were certainly made to
import the fibre into Great Britain in the latter part of the 18th
century, and it has been used in India for centuries in the making
of cord, twine and coarse fabrics, because the fibre is indigenous
to that country. And since all the manufacturing methods there, for
a considerable time were manual ones, the industry--if such it could
be called--moved along slowly, providing employment only for the
needs of a small section of the community on the Eastern shores.
The first small imports of jute fibre were due to the instigation of
Dr. Roxburgh and the East India Company, but it was only after
repeated requests that any attempt was made to utilize the samples
of jute for practical experiments The fibre was so unlike any of the
existing staples that those interested in textiles were not anxious
to experiment with it, but ultimately they were persuaded to do so;
these persistent requests for trials, and the interest which was
finally aroused, formed the nucleus of the existing important jute
industry.
Apart from the above-mentioned efforts, the introduction of the jute
fibre into Great Britain was delayed until 1822, when the first
small consignment reached Dundee--now the Western home of the jute
industry. This quantity was imported into this country with the
special object of having it treated by mechanical means, much in the
same way as flax fibre was being treated. At this period Dundee was
a comparatively important textile centre in regard to the spinning
and weaving of flax and hemp; it was, in consequence, only natural
that the longer, but otherwise apparently similar and coarser, jute
fibre should be submitted to the machinery in vogue for the
preparation and spinning of flax and hemp. When we say similar, we
mean in general appearance; it is now well-known that there is a
considerable difference between jute fibre and those of hemp and flax,
and hence the modifications in preparation which had ultimately to
be introduced to enable the jute fibre to be successfully treated.
These modifications shall be discussed at a later stage.
It might be stated that while only 368 cwt. of jute fibre was
reported as being shipped from Calcutta to this country in 1828, the
imports gradually increased as time passed on. The yarns which were
made from the fibre were heavier or thicker than those in demand for
the usual types of cloth, and it was desirable that other types of
cloth should be introduced so that these yarns could be utilized.
About the year 1838, representatives of the Dutch Government placed
comparatively large orders with the manufacturers for jute bags to
be used for carrying the crop of coffee beans from their West Indian
possessions. The subsequent rapid growth of the industry, and the
demand for newer types of cloth, are perhaps due more to the above
fortunate experiment than to any other circumstance.
By the year or season 1850-51, the British imports of jute fibre had
increased to over 28,000 tons, and they reached 46,000 tons in the
season 1860-61. Attention meanwhile had been directed to the
possibility of manufacturing jute goods by machinery in India--the
seat of the cultivation and growth of the fibre. At least such a
probability was anticipated, for in the year 1858 a small
consignment of machinery was despatched to Calcutta, and an attempt
made to produce the gunny bags which were typical of the Indian
native industry.
The great difference between the more or less unorganized hand
labour and the essential organization of modern mills and factories
soon became apparent, for in the first place it was difficult to
induce the natives to remain inside the works during the period of
training, and equally difficult to keep the trained operatives
constantly employed. Monetary affairs induced them to leave the
mills and factories for their more usual mode of living in the
country.
In the face of these difficulties, however, the industry grew in
India as well as in Dundee. For several years before the war, the
quantity of raw jute fibre brought to Dundee and other British ports
amounted to 200,000 tons. During the same period preceding the war,
nearly 1,000,000 tons were exported to various countries, while the
Indian annual consumption--due jointly to the home industry and the
mills in the vicinity of Calcutta--reached the same huge total of
one million tons.
The growth of the jute industry in several parts of the world, and
consequently its gradually increasing importance in regard to the
production of yarns and cloth for various purposes, enables it to be
ranked as one of the important industries in the textile group, and
one which may perhaps attain a much more important position in the
near future amongst our national manufacturing processes. As a
matter of fact, at the present time, huge extensions are
contemplated and actually taking place in India.
CHAPTER II. CULTIVATION
_Botanical and Physical Features of the Plant_. Jute fibre is
obtained from two varieties of plants which appear to differ only in
the shape of the fruit or seed vessel. Thus, the fruit of the
variety _Corchorus Capsularis_ is enclosed in a capsule of
approximately circular section, whereas the fruit of the variety
_Corchorus Olitorius_ is contained in a pod. Both belong to the
order _Tiliacea_, and are annuals cultivated mostly in Bengal and
Assam.
Other varieties are recorded, e.g. the _Corchorus Japonicus_ of Japan,
and the _Corchorus Mompoxensis_ used in Panama for making a kind of
tea, while one variety of jute plant is referred to in the book of
job as the Jew's Mallow; this variety _C. Olitorius_, has been used
in the East from time immemorial as a pot herb.
The two main varieties _C. Capsularis_ and _C. Olilorius_ are
cultivated in Bengal for the production of fibre, while for seed
purposes, large tracts of land are cultivated in Assam, and the
seeds exported for use principally in Mymensingh and Dacca.
The above two varieties of the jute plant vary in height from 5 to
15 feet, and, in a normal season, reach maturity in about four
months from the time of sowing. In some districts the stems of jute
plants are sometimes rather dark in colour, but, in general, they are
green or pink, and straight with a tendency to branch. The leaves
are alternate on the stems, 4 to 5 inches in length, and about 1-1/2
inches in breadth with serrated edges. Pale yellow flowers spring
from the axil (axilla) of the leaves, and there is an abundance of
small seeds in the fruit which, as mentioned, is characteristic of
the variety.
While many attempts have been made to cultivate jute plants in
various parts of the world, the results seem to indicate that the
necessary conditions for the successful cultivation of them are
completely fulfilled only in the Bengal area, and the geographical
position of this province is mainly responsible for these conditions.
On referring to a map of India, it will be seen that Bengal is
directly north of the bay of that name, and is bounded on the north
by the great Himalayan mountains.
During the winter period when the prevailing winds are from the north,
large areas of the mountainous regions are covered with snow, but
when the winds change and come from the south, and particularly
during the warmer weather, the moist warm air raises the general
temperature and also melts much of the snow on the mountain tracts.
The rain and melted snow swell the two great rivers on the east and
west of Bengal--the Patna and the Brahmaputra--and the tremendous
volume of water carries down decayed vegetable and animal matter
which is ultimately spread on the flat areas of Bengal as alluvial
deposits, and thus provides an ideal layer of soil for the
propagation of the jute plants.
The cultivation of land for the growing of jute plants is most
extensively conducted in the centres bordering on the courses of the
rivers, and particularly in Mymensingh, Dacca, Hooghly and Pabna,
and while 90 per cent. of the fibre is produced in Bengal, Orissa
and Bihar, there is 10 per cent. produced outside these areas.
The _Corchorus Capsularis_ variety is usually cultivated in the
higher and richer soils, while the _Corchorus Olitorius_ variety is
most suited for the lower-lying alluvial soils, and to the districts
where the rainfall is irregular; indeed, the _C. Olitorius_ may be
grown in certain other districts of India which appear quite
unsuitable for the _C. Capsularis_.
The farming operations in India are rather simple when compared with
the corresponding operations in this country; there is evidently not
the same necessity for extensive working of the Indian soil as there
is for the heavier lands; another reason for the primitive Eastern
methods may be the absence of horses.
The ploughs are made of wood and faced with iron. Bullocks, in teams
of two or more, are harnessed to the plough as shown in Fig. 1 where
a field is being ploughed as a preliminary process in jute
cultivation. The bullocks draw the plough in much the same way as
horses do in this country.
The operation of ploughing breaks up the soil, while the rough clods
may be broken by hand mallets or by the use of the "hengha"--a piece
of tree boll harnessed at the ends to a pair of bullocks.
The breaking up of the land prepares it for the cleaning process
which is performed by what are termed "ladders"; these ladders are
made of a few bamboos fixed cross-wise and provided with projecting
pins to scratch or open the soil, and to collect the roots of the
previous crop; they are the equivalent of our harrows, and may be
used repeatedly during the winter and spring seasons so that a fine
tilth may be produced.
When manure is essential, it is applied in the later ploughings, but
other large areas have artificial or chemical manures added at
similar stages in the process. Farm-yard manure is preferred, but
castor-cake and the water hyacinth--a weed--constitute good
substitutes.
After the soil has been satisfactorily prepared, the seed is sown by
hand at the period which appears most suitable for the particular
district. The usual sowing time is from February to the end of May,
and even in June in some districts where late crops can be obtained.
[Illustration: FIG. 1 NATIVES PLOUGHING THE GROUND]
There are early and late varieties of the plants, and a carefully
judged distribution of the varieties of seed over the districts for
the growing period will not only yield a succession of crops for
easy harvesting, but will also help the farmer in the selection of
seeds for other areas where atmospheric conditions differ.
It is a good practice, where possible, to sow the seed in two
directions at right angles to each other, and thus secure as uniform
a distribution as possible. The amount of seed used depends partly
upon the district, and in general from 10 lbs. to 30 lbs. per acre
are sown. The seed may cost about 8 annas or more per ser (about 2
lbs.).
[Illustration: FIG. 2 BREAKING UP THE SOIL, OR "LADDERING"]
Plants should be specially cultivated for the production of seed in
order to obtain the best results from these seeds for fibre plants.
Many of the ryots (farmers) use seed which has been collected from
plants grown from inferior seed, or from odd and often poor plants;
they also grow plants year after year on the same soil. The fibres
obtained, as a rule, and as a result of this method of obtaining
seeds, gradually deteriorate; much better results accrue when
succession of crops and change of seed are carefully attended to.
If the weather conditions are favourable, the seeds will germinate in
8 to 10 days, after which the plants grow rapidly. The heat and
showers of rain combined soon form a crust on the soil which should
be broken; this is done by means of another ladder provided with
long pins, and Fig. 2 illustrates the operation in process. This
second laddering process opens up the soil and allows the moisture
and heat to enter. The young plants are now thinned, and the ground
weeded periodically, until the plants reach a sufficient height or
strength to prevent the words from spreading.
The space between the growing plants will vary according to the
region; if there is a tendency to slow growth, there is an abundance
of plants; whereas, the thinning is most severe where the plants
show prospects of growing thick and tall.
In a normal season the plants will reach maturity in about 3 1/2 to
4 months from the time of sowing. Although different opinions are
held as to the best time for harvesting, that when the fruits are
setting appears to be most in favour; plants harvested at this stage
usually yield a large quantity of good fibre which can be perfectly
cleaned, and which is of good spinning quality.
The plants are cut down by hand and with home-made knives; in general,
these knives are of crude manufacture, but they appear to be quite
suitable for the purpose. A field of jute plants ready for cutting
will certainly form a delightful picture, but the prospect of the
operation of cutting indicates a formidable piece of work since it
requires about 10 to 14 tons of the green crop to produce about 10 to
15 cwt. of clean dry fibre.
CHAPTER III. RETTING
The method of separating the bast layer (in which the fibres are
embedded) from the stem of the plant requires a large supply of water,
since the plants must be completely submerged in the water for a
period varying from 8 to 30 days; such time is dependent upon the
period of the year and upon the district in which the operation is
performed.
The above operation of detaching the bast layer from the stem is
technically known as "retting," and a good type of retting or
steeping place is an off-set of a run, branch, or stream where the
water moves slowly, or even remains at rest, during the time the
plants are under treatment.
The disintegration of the structural part of the plant is due to a
bacterial action, and gas is given off during the operation. The
farmer, or ryot, and his men know what progress the action is making
by the presence of the air bells which rise to the surface; when the
formation of air bells ceases, the men examine the plants daily to
see that the operation does not go too far, otherwise the fibrous
layer would be injured, and the resulting fibre weak. The stems are
tested in these examinations to see if the fibrous layer, or bast
layer, will strip off clean from the wood or stem. When the ryot
considers that the layers are separated from the core sufficiently
easy, the work of steeping ceases, and the process of stripping is
commenced immediately. This latter process is conducted in various
ways depending upon the practice in vogue in the district.
In one area the men work amongst the water breaking up the woody
structure of the retted plants by means of mallets and cross rails
fixed to uprights in the water; others break the stems by hand;
while in other cases the stems are handed out of the water to women
who strip off the fibrous layer and preserve intact the central core
or straw to be used ultimately for thatching. The strips of fibre
are all cleaned and rubbed in the water to remove all the vegetable
impurities, and finally the fibre is dried, usually by hanging it
over poles and protecting it from the direct rays of the sun.
If the water supply is deficient in the vicinity where the plants
are grown, it may be advantageous to convey the fibrous layers to
some other place provided with a better supply of water for the
final washing and drying; imperfect retting and cleaning are apt to
create defects in the fibre, and to cause considerable trouble or
difficulties in subsequent branches of the industry.
Fig. 3 illustrates photomicrographs of cross sections of a jute plant.
The lower illustration represents approximately one quarter of a
complete cross section. The central part of the stem or pith is
lettered A; the next wide ring B is the woody matter; the outer
covering or cuticle is marked C; while the actual fibrous layer
appears between the parts B and C, and some of the fibres are
indicated by D. The arrows show the corresponding parts in the three
distinct views. The middle illustration shows an enlarged view of a
small part of the lowest view, while the upper illustration is a
further enlarged view of a small section of the middle view. It will
be seen that each group of fibres is surrounded by vegetable matter.
[Illustration: FIG. 3 PHOTOMICROGRAPHS OF CROSS SECTIONS OF A JUTE
PLANT]
Another method of stripping the fibrous layer off the stems or stalks,
and one which is practised in certain districts with the object of
preserving the straws, consists in breaking off a small portion, say
one foot, at the top end of the stem; the operative then grasps the
tops by the hand and shakes the plants to and fro in the water, thus
loosening the parts, after which the straws float out, leaving the
fibrous layer free. The straws are collected for future use, while the
fibre is cleaned and washed in the usual way.
CHAPTER IV. ASSORTING AND BALING JUTE FIBRE
The Indian raw jute trade is conducted under various conditions. The
method of marketing may be of such a nature that the farmers in some
districts may have to make a rough assortment of the fibre into a
number of qualities or grades, and these grades are well known in
the particular areas; on the other hand, the farmers may prefer to
sell the total yield of fibre at an overhead price per maund. A
maund is approximately equal to 8 lbs., and this quantity forms a
comparatively small bundle. In other cases, the fibre is made up into
what is known as a "drum"; this is a hand-packed bale of from 1 1/2
to 3 or 3 1/2 maunds; it is a very convenient size for transit in
India.
Practically one half of the total jute crop, of 9 to 10 million
bales of 400 lbs. each, is used in India, and the remaining half is
baled for export to the various parts of the world; a little over
one million bales are exported annually to Great Britain, the bulk
of this fibre comes to Dundee.
It is practically impossible for foreign purchasers to see the
material at the assorting stations, but the standardized method of
assorting and grading enables a purchaser to form a very good idea
of the quality of the fibre, and its suitability or otherwise for
special types of yarn and cloth. Thus, a form of selecting and
grading has been established on a basis that provides a very large
amount of jute each year of a quality which is known as "a first mark."
A mark, in general, in reference to fibre, is simply some symbol,
name, letter, monogram or the like, or a combination of two or
more, oft-times with reference to some colour, to distinguish the
origin of the fibre, the baler, or the merchant.
In normal years there is also a large quantity of fibre of a better
quality than what is known as "first mark," and this better quality
is termed "fine jute"; while there is yet a further lot, the quality
of which is below these good ones. Since there are hundreds of
different marks which are of value only to those connected directly
with the trade, it is unnecessary to dwell on the subject. The
following list, however, shows quotations of various kinds, and is
taken from the Market Report of the Dundee Advertiser of March, 1920.
The price of jute, like almost everything else, was at this date
very high, so in order to make comparisons with the 1920 and normal
prices, we introduce the prices for the corresponding grade, first
marks, for the same month in the years 1915 onwards.
JUTE PRICES, IN MARCH
First Marks
Year. Price per ton.
L. s. d. L. s. d.
1915 27 to 35 15
1916 44
1917 42 10
1918 51
1919 49
1920 70 (spot)
It is necessary to state that the assorting and balings are
generally so uniform that the trade can be conducted quite
satisfactorily with the aid of the usual safeguards under contract,
and guarantees regarding the properties of the fibre.
After these assorting operations are completed, the jute fibre is
made up into bundles or "bojahs" of 200 lbs. each, and two of these
200 lb. bundles are subsequently made up into a standard bale, the
weight of which is 400 lbs. This weight includes a permitted
quantity of binding rope, up to 6 lbs. in weight, while the
dimensions in the baling press of the 400 lb. bale are 4'1" X 1'6" X 1'
4".
[Illustration: FIG. 4 NATIVES CARRYING SMALL BALES OF JUTE FIBRE
FROM BOAT TO PRESS HOUSE]
Large quantities of the smaller and loosely-packed bales are
conveyed from the various places by boats to the baling houses or
press houses as they are termed. These are very large establishments,
and huge staffs of operatives are necessary to deal rapidly and
efficiently with the large number of bales. In Fig. 4 scores of
natives, superintended by a European, are seen carrying the smaller
bales on their heads from the river boat to the press house. It is,
of course, unnecessary to make the solid 400 lb. bales for Indian
consumption; this practice is usually observed only for jute which
is to be exported, and all such bales are weighed and measured at
the baling station by a Chamber of Commerce expert.
Most of the baling presses used in the press houses in the Calcutta
district are made in Liverpool, and are provided with the most
efficient type of pumps and mechanical parts. Fig. 5 illustrates one
of these huge presses with a number of natives in close proximity.
Two or three distinct operations are conducted simultaneously by
different groups of operatives, and ingenious mechanism is essential
for the successful prosecution of the work. Two such presses as that
illustrated in Fig. 5 are capable, under efficient administration, of
turning out 130 bales of 400 lbs. each in one hour. The fibre is
compressed into comparatively small bulk by hydraulic pressure equal
to 6,000 lbs. per square inch, and no packed bale must exceed in
cubical capacity 11 cubic feet after it leaves the press; it is
usual for freight purposes to reckon 5 bales or 55 cubic feet per ton.
(Now changed to 50 cubic feet.)
The jute bales are loaded either at the wharf or in the river from
barges into large steamers, many of which carry from 30,000 to
46,000 bales in one cargo to the European ports. One vessel brought
70,000 bales.
As already mentioned, jute is sold under guarantees as to quality,
and all disputes must be settled by arbitration. Although this is
the usual method of sale, it is not uncommon for quantities of jute
to be shipped unsold, and such quantities may be disposed of on the
"Spot." It is a common practice to sell a number of bales to sample,
such number depending generally upon the extent of the quantity, or
"parcel," as it is often called. The contract forms are very complete,
and enable the business to be conducted to the satisfaction of all
concerned in the trade.
[ILLUSTRATION: FIG. 5 NATIVES BAILING JUTE FIBRE IN A WATSON-FAWCETT
CYCLONE PRESS]
It will be understood that, in the yearly production of such a large
quantity of jute fibre from various districts, and obtained from
plants which have been grown under variable climatic and
agricultural conditions, in some cases the fibre will be of the
finest type procurable, while in other cases it will be of a very
indifferent type and unsuitable for use in the production of the
ordinary classes of yarns and fabrics. On the other hand, it should
be stated that there is such a wide range of goods manufactured, and
additional varieties occasionally introduced, that it appears
possible to utilize all the kinds of fibre in any year; indeed, it
seems as if the available types of fibre each season create demands
for a corresponding type of manufactured product.
The crops produced will, obviously, vary in amount and value annually,
but a few figures will help the reader to estimate in some degree
the extent of the industry and its development in various parts of
the world.
EXPORTS OF JUTE FROM INDIA
Year. Tons. Bales.
1828 18 300 lbs/bale
1832 182 300 lbs/bale
1833 300 300 lbs/bale
1834 828 300 lbs/bale
1835 1,222 300 lbs/bale
1836 16 300 lbs/bale
1837 171 300 lbs/bale
[Illustration: FIG. 6 VESSEL LADEN WITH JUTE AT QUAY-SIDE ADJOINING
JUTE SHEDS IN DUNDEE HARBOUR]
JUTE PRODUCTION IN INDIA
Season. Tons. Bales (400 lbs.).
1850-51. 28,247 158,183
1860-61. 46,182 258,619
1862-63. 108,776 609,146
1863-64. 125,903 707,056
1872-73. 406,335 2,275,476
1880-81. 343,596 1,924,137
1886-87. 413,664 2,316,518
1892-93. 586,258 3,083,023
1896-97. 588,141 3,293,591
1902-03. 580,967 3,253,414
1906-07. 829,273 4,643,929
1907-08. 1,761,982 9,867,100
1908-09. 1,135,856 6,360,800
1909-10. 1,302,782 7,295,580
1910-11 1,434,286 8,032,000
1911-12. 1,488,339 8,334,700
1912-13. 1,718,180 9,621,829
1913-14. 1,580,674 8,851,775
1914-15. 1,898,483 10,631,505
1915-16. 1,344,417 7,528,733
1916-17. 1,493,976 8,366,266
1917-18. 1,607,922 9,004,364
1918-19. 1,278,425 7,159,180
1919-20. 1,542,178 8,636,200
A large vessel containing bales of jute is berthed on the quay-side
adjoining the jute sheds in Fig. 6. The bales are raised quickly
from the hold by means of a hydraulic-engine, scarcely visible in Fig.
6 since it is at the far end of the vessel, but seen clearly in Fig.
7. When the bales are raised sufficiently high, they are guided to
the comparatively steep part of a chute from which they descend to
the more horizontal part as exemplified in Fig. 7. They are then
removed by means of hand-carts as shown, taken into the shed, and
piled or stored in some suitable arrangement with or without the aid
of a crane. Motor and other lorries are then used to convey the bales
to the various mills where the first actual process in what is termed
spinning takes place. It will be understood that the bales are stored
in the spinner's own stores after having been delivered as stated.
[Illustration: FIG. 7. HARBOUR PORTERS REMOVING BALES OF JUTE FROM
THE VESSEL SHOWN IN FIG. 6]
CHAPTER V. MILL OPERATIONS
_Bale Opening_. Each spinner, as already indicated, stores his
bales of jute of various "marks," i.e. qualities, in a convenient
manner, and in a store or warehouse from which any required number
of bales of each mark can be quickly removed to the preparing
department of the mill.
In the woollen industry, the term "blending" is used to indicate the
mixing of different varieties of material (as well as different
kinds of fibres) for the purpose of obtaining a mixture suitable for
the preparing and spinning of a definite quality and colour of
material. In much the same way, the term "batching" is used in the
jute industry, although it will be seen shortly that a more
extensive use is made of the word. A "batch," in its simplest
definition, therefore indicates a number of bales which is suitable
for subsequent handling in the Batching Department. This number may
include 5, 6, 7 or more bales of jute according to the amount of
accommodation in the preparing department.
All the above bales of a batch may be composed of the same standard
quality of jute, although the marks may be different. It must be
remembered that although the marks have a distinct reference to
quality and colour, they actually represent some particular firm or
firms of balers or merchants. At other times, the batch of 5 to 10
bales may be composed of different qualities of jute, the number of
each kind depending partly upon the finished price of the yarn,
partly upon the colour, and partly upon the spinning properties of
the combination.
It will be understood that the purpose for which the finished yarn
is to be used will determine largely the choice of the bales for any
particular batch. For example, to refer to a simple differentiation,
the yarn which is to be used for the warp threads in the weaving of
cloth must, in nearly every case, have properties which differ in
some respects from the yarn which is to be used as weft for the same
cloth.
On the whole, it will be found advantageous, when the same grade of
jute is required, to select a batch from different balers' marks so
that throughout the various seasons an average quality may be
produced. The same class of yarn is expected at all times of the year,
but it is well known that the properties of any one mark may vary
from time to time owing to the slight variations in the manipulation
of the fibre at the farms, and to the variations of the weather
during the time of growth, and during the season generally.
A list of the bales for the batch is sent to the batching department,
this list being known as a "batch-ticket." The bales are, of course,
defined by their marks, and those mentioned on the batch-ticket must
be rigidly adhered to for one particular class of yarn; if there is
any chance of one kind running short, the condition should be
notified in time so that a suitable mark may be selected to take its
place without effecting any great change in the character or quality
of the yarn.
When the number and kind of bales have been selected and removed
from the groups or parcels in the store or warehouse, they are
conveyed to the batching department, and placed in a suitable
position near the first machine in the series. It need hardly be
mentioned that since the fibre, during the operation of baling, is
subjected to such a high hydraulic pressure, the bale presents a
very solid and hard appearance, see Fig. 7, for the various
so-called "heads" of fibre have been squeezed together and forced
into a very small bulk. In such a state, the heads are quite
unfitted for the actual batching operation; they require to be opened
out somewhat so that the fibres will be more or less separated from
each other. This operation is termed "opening" and the process is
conducted in what is known as a "bale opener," one type of which is
illustrated in Fig. 8, and made by Messrs. Urquhart, Lindsay & Co.,
Ltd., Dundee.
The various bales of the batch are arranged in a suitable manner
near the feed side of the machine, on the left in the view, so that
they can be handled to the best advantage. The bands or ropes, see
Fig. 7, are removed from the bale in order that the heads or large
pieces of jute can be separated. If any irregularity in the
selection of the heads from the different bales of the batch takes
place in this first selection of the heads of jute, the faulty
handling may affect subsequent operations in such a way that no
chance of correcting the defect can occur; it should be noted at
this stage that if there are slight variations of any kind in the
fibres, it is advisable to make special efforts to obtain a good
average mixture; as a matter of fact, it is wise to insist upon a
judicious selection in every case. The usual variations are--the
colour of the fibre, its strength, and the presence of certain
impurities such as stick, root, bark or specks; if the pieces of jute,
which are affected adversely by any of the above, are carefully
mixed with the otherwise perfect fibre, most of the faults may
disappear as the fibre proceeds on its way through the different
machines.
[Illustration: FIG. 8 BALE OPENER _By permission of Messrs. Urquhart,
Lindsay & Co., Ltd_.]
The layers of heads are often beaten with a heavy sledge hammer in
hand batching, but for machine batching a bale opener is used, and
this operation constitutes the preliminary opening. As already
indicated, the heads of jute are fed into the machine from the left
in Fig. 8, each head being laid on a travelling feed cloth which
carries the heads of jute successively between a pair of feed
rollers from which they are delivered to two pairs of very
deeply-fluted crushing rollers or breakers. The last pair of
deep-fluted rollers is seen clearly on the right in the figure.
These two pairs of heavy rollers crush and bend the compressed heads
of jute and deliver them in a much softer condition to the delivery
sheet on the right. The delivery sheet is an endless cloth which has
a continuous motion, and thus the softened heads are carried to the
extreme right, at which position they are taken from the sheet by
the operatives. The upper rollers in the machine may rise in their
bearings against the downward pressure of the volute springs on the
bearings; this provision is essential because of the thick and thin
places of the heads.
A different type of bale opener, made by Messrs. Charles Parker, Sons, &
Co., Dundee, and designed from the Butchart patent is illustrated in
Fig. 9. It differs mainly from the machine illustrated in Fig. 8 in
the shape of the crushing or opening rollers.
It will be seen on referring to the illustration that there are
three crushing rollers, one large central roller on the top and
situated between two lower but smaller rollers. Each roller has a
series of knobs projecting from a number of parallel rings. The
knobs are so arranged that they force themselves into the hard
layers of jute, and, in addition to this action, the heads of jute
have to bend partially round the larger roller as they are passing
between the rollers. This double action naturally aids in opening up
the material, and the machine, which is both novel and effective,
gives excellent results in practice. The degree of pressure provided
for the top roller may be varied to suit different conditions of heads
of jute by the number of weights which are shown clearly in the
highest part of the machine in the form of two sets of heavy discs.
[Illustration: FIG. 9 BALE OPENER _By permission of Messrs. Charles
Parker, Sons, & Co_.]
The driving side, the feed cloth, and the delivery cloth in this
machine are placed similarly to the corresponding parts of the
machine illustrated in Fig. 8, a machine which also gives good
results in practice.
In both cases the large heads are delivered in such a condition that
the operatives can split them up into pieces of a suitable size
quite freely.
The men who bring in the bales from the store take up a position
near the end of the delivery cloth; they remove the heads of jute as
the latter approach the end of the table, and then pass them to the
batchers, who split them. The most suitable size of pieces are 2-1/2
to 3 lbs. for a piece of 7 feet to 8 feet in length, but the size of
the pieces is regulated somewhat by the system of feeding which is
to be adopted at the breaker-card, as well as by the manager's
opinion of what will give the best overall result.
After the heads of jute have been split up into suitable smaller
pieces, they are placed in any convenient position for the batcher
or "striker-up" to deal with. If the reader could watch the above
operation of separating the heads of jute into suitable sizes, it
would perhaps be much easier to understand the process of
unravelling an apparently matted and crossed mass of fibre. As the
loosened head emerges from the bale-opener, Figs. 8 or 9, it is
placed over the operative's arm with the ends of the head hanging,
and by a sort of intuition acquired by great experience, she or he
grips the correct amount of fibre between the fingers, and by a
dexterous movement, and a simultaneous shake of the whole piece, the
handful just comes clear of the bulk and in much less time than it
takes to describe the operation.
As the pieces are thus detached from the bulk, they are laid on
stools or tables, or in stalls or carts, according to the method by
means of which the necessary amount of oil and water is to be added
for the essential process of lubrication; this lubrication enables
the fibre to work freely in the various machines.
CHAPTER VI. BATCHING
_Softening and Softening Machines_. Two distinct courses are
followed in the preparation of the jute fibre after it leaves the
bale opener, and before it is carded by the breaker card. These
courses are designated as--
1. Hand Batching.
2. Machine Batching.
In the former process, which is not largely practised, the pieces of
jute are neatly doubled, while imparting a slight twist, to
facilitate subsequent handling, and laid in layers in large carts
which can be wheeled from place to place; if this method is not
convenient, the pieces are doubled similarly and deposited in large
stalls such as those illustrated in Fig. 10.
On the completion of each layer, or sometimes two layers, the
necessary measured amount of oil is evenly sprayed by hand over the
pieces from cans provided with suitable perforated outlets--usually
long tubes. After the oil has been added, water, from a similar
sprayer attached by tubing to a water tap, is added until the
attendant has applied what he or she considers is the proper quantity.
The ratio between a measured amount of oil and an unmeasured amount
of water is thus somewhat varied, and for this reason the above
method is not to be commended. A conscientious worker can, however,
with judgment, introduce satisfactory proportions which are, of
course, supplied by the person in charge. In Fig. 10, the tank on
the right is where the oil is stored, while the oil can, and the
spray-pipe and tube for water, are shown near the second post or
partition on the right.
[ILLUSTRATION: FIG. 10 HAND-BATCHING DEPARTMENT WITH UNPREPARED AND
PREPARED FIBRE]
The first stall--that next to the oil tank--in Fig. 10 is filled
with the prepared pieces, and the contents are allowed to remain
there for some time, say 24 hours, in order that the material may be
more or less uniformly lubricated or conditioned. At the end of this
time, the pieces are ready to be conveyed to and fed into the
softening machines where the fibres undergo a further process of
bending and crushing.
All softening machines for jute, or softeners as they are often
called, are similar in construction, but the number of pairs of
rollers varies according to circumstances and to the opinions of
managers. Thus, the softener illustrated in Fig. 11, which, in the
form shown, is intended to treat jute from the above-mentioned stalls,
is made with 47, 55, 63 or 71 pairs of rollers or any other number
which, minus 1, is a measure of 8. The sections are made in 8's. The
illustration shows only 31 pairs.
The first pair of rollers--that next to the feed sheet in the
foreground of Fig. 11--is provided with straight flutes as clearly
shown. All the other rollers, however, are provided with oblique
flutes, such flutes making a small angle with the horizontal. What
is often considered as a standard softening machine contains 63
pairs of fluted rollers besides the usual feed and delivery rollers.
As mentioned above, this number is varied according to circumstances.
The lubricated pieces of jute are fed on to the feed roller sheet,
and hence undergo a considerable amount of bending in different ways
before they emerge from the delivery rollers at the other end of the
machine.
[Illustration: Fig. 11 Softening machine without batching apparatus]
Machine batching is preferred by many firms because the application
of oil and water, and the proportion of each, are much more uniform
than they are by the above mentioned process of hand batching. On the
other hand, there is no time for conditioning the fibre because the
lubrication and the softening are proceeding simultaneously,
although conditioning may proceed while the fibre remains in the
cart after it has left the softener.
The mechanical apparatus as made by Messrs. Urquhart, Lindsay & Co.,
Ltd., Dundee, for depositing the oil and water on the pieces or
"stricks" of jute is illustrated in Fig. 12. The actual lubricating
equipment is situated on the top of the rectangular frame in the
centre of the illustration. This frame is bolted to the side frames
of the softening machine proper, say that shown in Fig. 11. Its
exact position, with respect to its distance from the feed, is a
matter of choice, but the liquid is often arranged to fall on to the
material at any point between the second and twelfth rollers.
In Fig. 12 the ends of 13 rollers of the upper set are seen clearly,
and these upper rollers are kept hard in contact with the stricks or
pieces of jute by means of the powerful springs shown immediately
above the roller bearings and partially enclosed in bell-jars.
Outside the rectangular frame in Fig. 12 are two rods, one vertical
and the other inclined. The straight or vertical rod is attached by
suitable levers and rods to the set-on handles at each end of the
machine and to the valve of the water pipe near the top of the frame,
while the upper end of the inclined or oblique rod is fulcrumed on a
rod projecting from the frame. The lower or curved end of the
oblique rod rests against the boss of one of the upper rollers.
[Illustration: Fig. 12]
The water valve is opened and closed with the starting and stopping
of the machine, but the oblique rod is moved only when irregular
feeding takes place. Thus, the upper rollers rise slightly against
the pressure of the springs when thick stricks appear; hence, when a
thick place passes under the roller which is in contact with the
curved end of the oblique rod, the end moves slightly clockwise, and
thus rotates the fulcrum rod; this results in an increased quantity
of oil being liberated from the source of supply, and the mechanism
is so arranged that the oil reaches the thick part of the strick.
When the above-mentioned upper roller descends, due to a decrease in
the thickness of the strick, the oblique rod and its fulcrum is
moved slightly counter-clockwise, and less oil is liberated for the
thin part of the strick. It will be understood that all makers of
softening machines supply the automatic lubricating or batching
apparatus when desired.
A view of a softener at work appears in Fig. 13. The bevel wheels at
the end of the rollers are naturally covered as a protection against
accidents. In many machines safety appliances are fitted at the feed
end so that the machine may be automatically stopped if the
operative is in danger. The batching apparatus for this machine is
of a different kind from that illustrated in Fig. 12; moreover, it
is placed nearer the feed rollers than the twelfth pair. The feed
pipes for the oil and the water are shown coming from a high plane,
and the supply is under the influence of chain gearing as shown on
the right near the large driving belt from the drum on the shafting.
The feed roller in this machine is a spirally fluted one, and the
nature of the flutes is clearly emphasized in the view. The barrow
of jute at the far end of the machine is built up from stricks which
have passed through the machine, and these stricks are now ready for
conditioning, and will be stored in a convenient position for future
treatment.
[Illustration: Fig. 13 Softening machine with batching apparatus]
While the jute as assorted and baled for export from India is graded
in such a way that it may be used for certain classes of yarn
without any further selection or treatment, it may be possible to
utilize the material to better advantage by a judicious selection
and treatment after it has undergone the operation of batching.
What are known as cuttings are often treated by a special machine
known as a "root-opener." The jute cuttings are fed into the
machines and the fibre rubbed between fixed and rotating pins in
order to loosen the matted ends of stricks. Foreign matter drops
through the openings of a grid to the floor, and the fibre is
delivered on to a table, or, if desired, on to the feed sheet of the
softener.
The root ends of stricks are sometimes treated by a special machine
termed a root-comber with the object of loosening the comparatively
hard end of the strick. A snipping machine or a teazer may also be
used for somewhat similar purposes, and for opening out ropes and
similar close textures.
The cuttings may be partially loosened by means of blows from a
heavy iron bar; boiling water is then poured on the fibre, and then
the material is built up with room left for expansion, and allowed
to remain in this condition for a few days. A certain quantity of
this material may then be used along with other marks of jute to
form a batch suitable for the intended yarn.
A very common practice is to cut the hard root ends off by means of
a large stationary knife. At other times, the thin ends of the
stricks are also cut off by the same instrument. These two parts are
severed when it is desired to utilize only the best part of the
strick. The root ends are usually darker in colour than the remainder,
and hence the above process is one of selection with the object of
securing a yarn which will be uniform in colour and in strength.
CHAPTER VII. CARDING
_Breaker and Finisher Cards_. After the fibre from the softening
machine has been conditioned for the desired time, it is ready for
one of the most important processes in the cycle of jute manufacture;
this process is termed carding, and is conducted in two distinct
types of machines--
1. The breaker card.
2. The finisher card.
The functions of the two machines are almost identical; indeed, one
might say that the work of carding should be looked upon as one
continuous operation.
The main difference between the two types of machines is in the
method of feeding, and the degree of fineness or setting of the
small tools or pins which perform the work. In both cases the action
on the stricks of jute is equivalent to a combined combing and
splitting movement, and the pins in the various rollers move
relatively to each other so that while the pins of a slowly-moving
roller allow the strick or stricks (because there are several side
by side) to pass slowly and gradually from end to end, the pins of
another but quickly-moving roller perform the splitting and the
combing of the fibre. The pins of the slowly-moving roller hold, so
to speak, the strick, while the pins of the quickly-moving roller
comb out the fibres and split adhering parts asunder so as to make a
comparatively fine division.
The conditioned stricks from the softening machine are first
arranged in some suitable receptacle and within easy reach of the
operative at the back or feed side of the breaker card. A receptacle,
very similar to that used at the breaker card, appears near the far
end of the softening machine in Fig. 13.
A modern breaker card is illustrated in Fig. 14. The feed or back of
the card is on the extreme right, the delivery or front of the card
on the extreme left, while the gear side of the card is facing the
observer. The protecting cages were removed so that the wheels would
be seen as clearly as possible.
Some of the stricks of fibre are seen distinctly on the feed side of
the figure; they are accommodated, as mentioned, in a channel-shaped
stand on the far side of the inclined feed sheet, or feed cloth,
which leads up to and conveys the stricks into the grip of the
feeding apparatus. This particular type is termed a "shell" feed
because the upper contour of the guiding feed bracket is shaped
somewhat like a shell. There is a gradually decreasing and
suitably-sized gap between the upper part of the shell and the pins
of the feed roller.
The root ends of the pins in this roller lead, and the stricks of
fibre are gripped between the pins and the shell, and simultaneously
carried into the machine where they come into contact with the
points of the pins in the rapidly-revolving large roller, termed a
cylinder. The above-mentioned combing and splitting action takes
place at this point as well as for a distance of, say, 24 inches to
30 inches below. The fibres which are separated at this stage are
carried a little further round until they come into contact with the
points of the pins in the above-mentioned slowly-moving roller,
termed a "worker," and while the fibres are moving slowly forward
under the restraining influence of the worker, they are further
combed and split. A portion of the fibres is carried round by the
pins of the worker from which such fibres are removed by the
quicker moving pins of the second roller of the pair, termed a
"stripper," and in turn these fibres are removed from the pins of
the stripper by the much quicker moving pins of the cylinder.
[Illustration: FIG. 14 MODERN BREAKER CARD]
The above operations conducted by the first pair of rollers (worker
and stripper) in conjunction with the cylinder, are repeated by a
second and similar pair of rollers (worker and stripper), and ultimately
the thin sheet of combed and split fibres comes into contact with the
pins of the doffer from which it is removed by the drawing and pressing
rollers. The sheet of fibres finally emerges from these rollers into
the broad and upper part of the conductor. This conductor, made mostly
of tin and V-shaped, is shown clearly on the left of the machine in
Fig. 14. Immediately the thin film or sheet of fibres enters the
conductor, it is caused as a body gradually to contract in width and,
of course, to increase in thickness, and is simultaneously guided and
delivered to the delivery rollers, and from these to the sliver can,
distinctly seen immediately below the delivery rollers. The sliver is
seen emerging from the above rollers and entering the sliver can.
The fibres in this machine are thus combed, split and drawn forward
relatively to each other, in addition to being arranged more or less
parallel to each other. The technical term "draft" is used to
indicate the operation of causing the fibres to slip on each other,
and in future we shall speak about this attenuation or drawing out
of the fibres by this special term "draft."
It will be evident that, since the sliver is delivered into the can
at the rate of about 50 yards per minute, this constant flow will
soon provide a sufficient length of sliver to fill a sliver can,
although the latter may hold approximately 20 lbs. The machine must,
of course, deliver its quota to enable succeeding machines to be
kept in practically constant work. As a matter of fact, the machines
are arranged in what are termed "systems," so that this desirable
condition of a constant and sufficient feed to all may be
satisfactorily fulfilled.
The driving or pulley side of the breaker card is very similar to
that shown in Fig. 15 which, however, actually represents the pulley
side of one type of finisher card as made by Messrs. Douglas Fraser &
Sons, Ltd., Arbroath. All finisher cards are fed by slivers which
have been made as explained in connection with the breaker card, but
there are two distinct methods of feeding the slivers, or rather of
arranging the slivers at the feed side. In both cases, however, the
full width of the card is fed by slivers laid side by side, with,
however, a thin guide plate between each pair, and one at each
extreme end.
One very common method of feeding is to place 10 or 12 full sliver
cans--which have been prepared at the breaker card--on the floor and
to the right of the machine illustrated in Fig. 15. The sliver from
each can is then placed into the corresponding sliver guide, and
thus the full width of the machine is occupied. The slivers are
guided by the sliver guides on to an endless cloth or "feed sheet"
which, in turn, conveys them continuously between the feed rollers.
The feed apparatus in such machines is invariably of the roller type,
and sometimes it involves what is known as a "porcupine" roller. It
will be understood that the feeding of level slivers is a different
problem from that which necessitates the feeding of comparatively
uneven stricks.
[Illustration: By permission of Messrs. Douglas Fraser & Sons, Ltd.
FIG. 15 FINISHER CARD WITH DRAWING-HEAD]
The slivers travel horizontally with the feed-sheet and enter the
machine at a height of about 4 feet from the floor. They thus form,
as it were, a sheet of fibrous material at the entrance, and this
sheet of fibres comes in contact with the pins of the various pairs
of rollers, the cylinder, and the doffer, in much the same way as
already described in connection with the breaker card. There are,
however, more pairs of rollers in the finisher card than there are
in the breaker card, for while the latter is provided with two pairs
of rollers, the former may be arranged with 3, 4, 5 or even 6 pairs
of rollers (6 workers and 6 strippers). The number of pairs of
rollers depends upon the degree of work required, and upon the
opinions of the various managers.
There are two distinct types of finisher cards, viz--
1. Half-circular finisher cards.
2. Full-circular finisher cards.
The machine illustrated in Fig. 15 is of the latter type, and such
machines are so-called because the various pairs of rollers are so
disposed around the cylinder that they occupy almost a complete
circle, and the fibre under treatment must move from pair to pair to
undergo the combing and splitting action before coming into contact
with the doffer. There are five pairs of rollers in the machine in
Fig. 15, and all the rollers are securely boxed in, and the wheels
fenced. The arrangement of the wheels on the gear side is very
similar to that shown in connection with the breaker card in Fig. 14,
and therefore requires no further mention. Outside the boxing comes
the covers, shown clearly at the back of the machine in Fig. 15, and
adapted to be easily and quickly opened when it is desired to
examine the rollers and other parts.
The slivers, after having passed amongst the pins of the various
rollers, and been subjected to the required degree of draft, are
ultimately doffed as a thin film of fibres from the pins of the
cylinder and pass between the drawing rollers to the conductor. The
conductor of a finisher card is made in two widths, so that half the
width of the film enters one section and the other half enters the
other section. These two parallel sheets, split from one common sheet,
traverse the two conductors and are ultimately delivered as two
slivers about 6 inches above the point or plane in which the 10 or 12
slivers entered, and on to what is termed a "sliver plate." The two
slivers are then guided by horns projecting from the upper surface
of the sliver plate, made to travel at right angles to the direction
of delivery from the mouths of the conductors, and then united to
pass as a single sliver between a pair of delivery rollers on the
left of the feed and delivery side and finally into a sliver can.
In special types of finishing cards, an extra piece of
mechanism--termed a draw-head--is employed. The machine illustrated
in Fig. 15 is provided with this extra mechanism which is supported
by the small supplementary frame on the extreme right. This special
mechanism is termed a "Patent Push Bar Drawing Head," and the
function which it performs will be described shortly; in the
meantime it is sufficient to say that it is used only when the
slivers from the finisher card require extra or special treatment. A
very desirable condition in connection with the combination of a
finisher card and a draw-head is that the two distinct parts should
work in unison. In the machine under consideration, the feed and
delivery rollers of the card stop simultaneously with the stoppage
of the draw-head mechanism.
One of the chief aims in spinning is that of producing a uniform
thread; uniform not only in section, but in all other respects. A
so-called level thread refers, in general, to a uniform diameter,
but there are other equally, if not more, important phases connected
with the full sense of the word uniform.
It has already been stated that in the batching department various
qualities of jute are mixed as judiciously as possible in order to
obtain a satisfactory mixture. Fibres of different grades and marks
vary in strength, colour, cleanness, diameter, length and suppleness;
it is of the utmost importance that these fibres of diverse
qualities should be distributed as early as possible in the process
so as to facilitate the subsequent operations.
[Illustration: _By permission of Messrs. James F. Low & Co., Ltd. _
FIG. 16 WASTE TEAZER]
However skilfully the work of mixing the stricks is performed in the
batching department, the degree of uniformity leaves something to be
desired; further improvement is still desirable and indeed necessary.
It need hardly be said, however, that the extent of the improvement,
and the general final result, are influenced greatly by the care
which is exercised in the preliminary processes.
The very fact of uniting 10 or 12 slivers at the feed of the
finisher card mixes 10 or 12 distinct lengths into another new length,
and, in addition, separates in some measure the fibres of each
individual sliver. It must not be taken for granted that the new
length of sliver is identical with each of the individual lengths
and ten or twelve times as bulky. A process of drafting takes place
in the finisher card, so that the fibres which compose the combined
10 or 12 slivers shall be drawn out to a draft of 8 to 16 or even
more; this means that for every yard of the group of slivers which
passes into the machine there is drawn out a length of 8 to 16 yards
or whatever the draft happens to be. The resulting sliver will
therefore be approximately two-thirds the bulk of each of the
original individual slivers. The actual ratio between them will
obviously depend upon the actual draft which is imparted to the
material by the relative velocities of the feed and delivery rollers.
It is only natural to expect that a certain amount of the fibrous
material will escape from the rollers; this forms what is known as
card waste. And in all subsequent machines there is produced, in
spite of all care, a percentage of the amount fed into the machine
which is not delivered as perfect material. All this waste from
various sources, e.g. thread waste, rove waste, card waste, ropes,
dust-shaker waste, etc., is ultimately utilized to produce sliver
for heavy sacking weft.
The dust-shaker, as its name implies, separates the dust from the
valuable fibrous material, and finally all the waste products are
passed through a waste teazer such as that made by Messrs. J. F. Low &
Co., Ltd., Monifieth, and illustrated in Fig. 16. The resulting mass
is then re-carded, perhaps along with other more valuable material,
and made into a sliver which is used, as stated above, in the
production of a cheap and comparatively thick weft such as that used
for sacking.
CHAPTER VIII. DRAWING AND DRAWING FRAMES
The operations of combing and splitting as performed in both the
breaker and finisher card are obviously due to the circular movement
of the pins since all these (with the single exception of those in
the draw-head mechanism of certain finisher cards) are carried on the
peripheries of rotating rollers. In the draw-head mechanism, the
pins move, while in contact with the fibres, in a rectilinear or
straight path. In the machines which fall to be discussed in this
chapter, viz., the "drawing frames," the action of the pins on the
slivers from the finisher card is also in a straight path; as a
matter of fact, the draw-head of a finisher card is really a small
drawing frame, as its name implies. Moreover, each row or rather
double row, of pins is carried separately by what is termed a
"faller." The faller as a whole consists of three parts:
1. A long iron or steel rod with provision for being
moved in a closed circuit.
2. Pour or six brass plates, termed "gills" or
"stocks," fixed to the rod.
3. A series of short pins (one row sometimes about
1/8 in. shorter than the second row), termed gill or
hackle pins, and set perpendicularly in the above
gills.
The numbers of fallers used is determined partly by the particular
method of operating the fallers, but mostly by the length of the
fibre. The gill pins in the fallers are used to restrain the
movements of the fibres between two important pairs of rollers.
There are actually about four sets of rollers from front to back of
a drawing frame; one set of three rollers constitute the "retaining"
rollers; then comes the drawing roller and its large pressing roller;
immediately after this pair is the "slicking" rollers, and the last
pair is the delivery rollers. The delivery rollers of one type of
drawing frame, called the "push-bar" drawing frame, and made by
Messsrs. Douglas Fraser & Sons, Ltd., Arbroath, are seen distinctly
in Fig. 17, and the can or cans into which the slivers are
ultimately delivered are placed immediately below one or more
sections of these rollers and in the foreground of the illustration.
The large pressing rollers, which are in contact with the drawing
roller, occupy the highest position in the machine and near the
centre of same. Between these rollers and the retaining rollers are
situated the above-mentioned fallers with their complements of gill
pins, forming, so to speak, a field of pins.
Each sliver, and there maybe from four to eight or more in a set, is
led from its sliver can at the far side of the machine to the sliver
guide and between the retaining rollers. Immediately the slivers
leave the retaining rollers they are penetrated by the gill pins of
a faller which is rising from the lower part of its circuit to the
upper and active position. Each short length of slivers is
penetrated by the pins of a rising faller, these coming up
successively as the preceding one moves along at approximately the
same surface speed as that of the retaining rollers. The sheet of
pins and their fallers are thus continuously moving towards the
drawing rollers and supporting the slivers at the same time. As each
faller in succession approaches close to the drawing rollers, it is
made to descend so that the pins may leave the fibres, and from this
point the faller moves backwards towards the retaining roller until
it reaches the other end ready to rise again in contact with the
fibres and to repeat the cycle as just described. It will thus be
seen that the upper set of fallers occupy the full stretch between
the retaining rollers and the drawing rollers, but there is always
one faller leaving the upper set at the front and another joining
the set at the back.
[Illustration: Fig. 17 Push-bar drawing frame]
The actual distance between the retaining rollers and the drawing
rollers is determined by the length of the fibre, and must in all
cases be a little greater than the longest fibre. This condition is
necessary because the surface speed of the drawing roller is much
greater than that of the retaining rollers; indeed, the difference
between the surface speeds of the two pairs of rollers is the actual
draft.
Between the retaining and drawing rollers the slivers are embedded
in the gill pins of the fallers, and these move forward, as mentioned,
to support the stretch of slivers and to carry the latter to the nip
of the drawing rollers. Immediately the forward ends of the fibres
are nipped between the quickly-moving drawing rollers, the fibres
affected slide on those which have not yet reached the drawing
rollers, and, incidentally, help to parallelize the fibres. It will
be clear that if any fibre happened to be in the grip of the two
pairs of rollers having different surface speeds, such fibre would be
snapped. It is to avoid this rupture of fibres that the distance
between the two sets of rollers is greater than the longest fibres
under treatment. The technical word for this distance is "reach."
On emerging from the drawing rollers, the combed slivers pass
between slicking rollers, and then approach the sliver plate which
bridges the gap between the slicking rollers and the delivery rollers,
and by means of which plate two or more individual slivers are
diverted at right angles, first to join each other, and then again
diverted at right angles to join another sliver which passes
straight from the drawing rollers and over the sliver plate to the
guide of the delivery rollers. It will thus be seen that a number of
slivers, each having been drawn out according to the degree of draft,
are ultimately joined to pass through a common sliver guide or
conductor to the nip of the delivery rollers, and thence into a
sliver can.
The push-bar drawing illustrated in Fig. 17, or some other of the
same type, is often used as the first drawing frame in a set. With
the exception of the driving pulleys, all the gear wheels are at the
far end of the frame, and totally enclosed in dust-proof casing. The
set-on handles, for moving the belt from the loose pulley to the
fast pulley, or _vice versa_, are conveniently situated, as shown,
and in a place which is calculated to offer the least obstruction to
the operative. The machines are made with what are known as
"two heads" or "three heads." It will be seen from the large
pressing rollers that there are two pairs; hence the machine is a
"two-head" drawing frame.
The slivers from the first drawing frame are now subjected to a
further process of doubling and drafting in a very similar machine
termed the second drawing frame. The pins in the gills for this
frame are rather finer and more closely set than those in the first
drawing frame, but otherwise the active parts of the machines, and
the operations conducted therein, are practically identical, and
therefore need no further description. It should be mentioned,
however, that there are different types of drawing frames, and their
designation is invariably due to the particular manner in which the
fallers are operated while traversing the closed circuit. The names
of other drawing frames appear below.
Spiral or screw gill;
Open link chain;
Rotary;
Ring Carrier
Circular.
For the preparation of slivers for some classes of yarn it is
considered desirable to extend the drawing and doubling operation in
a third drawing frame; as a rule, however, two frames are considered
sufficient for most classes of ordinary yarn.
CHAPTER IX. THE ROVING FRAME
The process of doubling ends with the last drawing frame, but there
still remains a process by means of which the drafting of the
slivers and the parallelization of the fibres are continued. And, in
addition to these important functions, two other equally important
operations are conducted simultaneously, viz., that of imparting to
the drawn out sliver a slight twist to form what is known as a
"rove" or roving, and that of winding the rove on to a large rove
bobbin ready for the actual spinning frame.
The machine in which this multiple process is performed is termed a
"roving frame." Such machines are made in various sizes, and with
different types of faller mechanism, but each machine is provided
for the manipulation of two rows of bobbins, and, of course, with
two rows of spindles and flyers. These two rows of spindles, flyers,
and rove bobbin supports are shown clearly in Fig. 18, which
represents a spiral roving frame made by Messrs. Douglas Fraser &
Sons, Ltd., Arbroath.
Each circular bobbin support is provided with pins rising from the
upper face of the disc, and these pins serve to enter holes in the
flange of the bobbin and thus to drive the bobbin. The discs or
bobbin supports are situated in holes in the "lifter rail" or
"builder rail" or simply the "builder"; the vertical spindles pass
through the centre of the discs, each spindle being provided with a
"flyer," and finally a number of plates rest upon the tops of the
spindles.
[Illustration: FIG. 18 ROVING FRAME _By Permission of Messrs.
Douglas Fraser & Sons, Ltd_.]
A roving machine at work is shown in Fig. 19, and it will be seen
that the twisted sliver or rove on emerging from the drawing rollers
passes obliquely to the top of the spindle, through a guide eye,
then between the channel-shaped bend at the upper part of the flyer,
round the flyer arm, through an eye at the extreme end of either of
the flyer arms, and finally on to the bobbin. Each bobbin has its
own sliver can (occasionally two), and the sliver passes from this
can between the sides of the sliver guide, between the retaining
rollers, then amongst the gill pins of the fallers and between the
drawing (also the delivery) rollers. Here the sliver terminates
because the rotary action of the flyer imparts a little twist and
causes the material to assume a somewhat circular sectional form.
From this point, the path followed to the bobbin is that described
above.
As in all the preceding machines, the delivery speed of the sliver
is constant and is represented by the surface speed of the periphery
of the delivery rollers, this speed approximates to about 20 yards
per minute. The spindles and their flyers are also driven at a
constant speed, because in all cases we have--
spindle speed = delivery x twist.
There is thus a constant length of yarn to be wound on the rove
bobbin per minute, and the speed of the bobbin, which is driven
independently of the spindle and flyer, is constant for any one
series of rove coils on the bobbin. The speed of the bobbin differs,
however, for each complete layer of rove, simply because the
effective diameter of the material on the bobbin changes with the
beginning of each new layer.
The eyes of the flyers always rotate in the same horizontal plane,
and hence the rove always passes to the bobbins at the same height
from any fixed point. The bobbins, however, are raised gradually by
the builder during the formation of each layer from the top of the
bobbin to the bottom, and lowered gradually by the builder during
the formation of each layer from bottom to top. In other words, the
travel of the builder is represented by the distance between the
inner faces of the flanges of the rove bobbin.
[Illustration: FIG. 19 ROVING FRAME FAIRBAIRN'S ROVING FRAME IN WORK]
Since every complete layer of rove is wound on the bobbin in virtue
of the joint action of the spindle and flyer, the rotating bobbin,
and the builder, each complete traverse of the latter increases the
combined diameter of the rove and bobbin shaft by two diameters of
the rove. It is therefore necessary to impart an intermittent and
variable speed to the bobbin. The mechanism by means of which this
desirable and necessary speed is given to the bobbin constitutes one
of the most elegant groups of mechanical parts which obtains in
textile machinery. Some idea of the intricacy of the mechanism, as
well as its value and importance to the industry, may be gathered
from the fact that a considerable number of textile and mechanical
experts struggled with the problem for years; indeed 50 years
elapsed before an efficient and suitable group of mechanical parts
was evolved for performing the function.
The above group of mechanical parts is known as "the differential
motion," and the difficulties in constructing its suitable gearing
arose from the fact that the speed of the rove passing on to the
various diameters must be maintained throughout, and must coincide
with the delivery of yarn from the rollers, so that the attenuated
but slightly twisted sliver can be wound on to the bobbin without
strain or stretch. The varying motion is regulated and obtained by a
drive, either from friction plates or from cones, and the whole gear
is interesting, instructive--and sometimes bewildering--two distinct
motions, a constant one and a variable one, are conveyed to the
bobbins from the driving shaft of the machine.
The machine illustrated in Fig. 18 is of special design, and the
whole train of gear, with the exception of a small train of wheels
to the retaining roller, is placed at the pulley end--that nearest
the observer. The gear wheels are, as shown, efficiently guarded,
and provision is made to start or stop the machine from any position
on both sides. The machine is adapted for building 10 in. X 5 in.
bobbins, i.e. 10 in. between the flanges and 5 in. outside diameter,
and provided with either 56 or 64 spindles, the illustration showing
part of a machine and approximately 48 spindles.
The machines for rove (roving frames) are designated by the size of
the bobbin upon which the rove is wound, e.g. 10 in. x 5 in. frame,
and so on; this means that the flanges of the bobbin are 10 in.
apart and 5 in. in diameter, and hence the traverse of the builder
would be 10 in. The 10 in. x 5 in. bobbin is the standard size for
the ordinary run of yarns, but 9 in. x 4-1/2 in. bobbins are
used for the roves from which finer yarns are spun. When the
finished yarn appears in the form of rove (often termed spinning
direct), as is the case for heavier sizes or thick yarns, 8 in. x 4
in. bobbins are largely used.
Provision is made on each roving frame for changing the size of rove
so as to accommodate it for the subsequent process of spinning and
according to the count of the required yarn; the parts involved in
these changes are those which affect the draft gearing, the twist
gearing, and the builder gearing in conjunction with the automatic
index wheel which acts on the whole of the regulating motion.
CHAPTER X. SPINNING
The final machine used in the conversion of rove to the size of yarn
required is termed the spinning frame. The actual process of
spinning is performed in this machine, and, although the whole
routine of the conversion of fibre into yarn often goes under the
name of spinning, it is obvious that a considerable number of
processes are involved, and an immense amount of work has to be done
before the actual process of spinning is attempted. The nomenclature
is due to custom dating back to prehistoric times when the
conversion of fibre to yarn was conducted by much simpler apparatus
than it is at present; the established name to denote this
conversion of fibre to yarn now refers only to one of a large number
of important processes, each one of which is as important and
necessary as the actual operation of spinning.
A photographical reproduction of a large spinning flat in one of the
Indian jute mills appears in Fig. 20, showing particularly the wide
"pass" between two long rows of spinning frames, and the method
adopted of driving all the frames from a long line shaft. Spinning
frames are usually double-sided, and each side may contain any
practicable number of spindles; 64 to 80 spindles per side are
common numbers.
[Illustration: FIG 20. AN INDIAN SPINNING FLAT]
The rove bobbins, several of which are clearly seen in Fig. 20, are
brought from the roving frame and placed on the iron pegs of a creel
(often called a hake) near the top of the spinning frame-actually
above all moving parts of the machine. Each rove bobbin is free to
rotate on its own peg as the rove from it is drawn downwards by the
retaining rollers. The final drafting of the material takes place in
this frame, and a considerable amount of twist is imparted to the
drawn out material; the latter, now in the desired form and size of
yarn, is wound simultaneously on to a suitable size and form of
spinning bobbin.
When the rove emerges from the retaining rollers it is passed over a
"breast-plate," and then is entered into the wide part of the
conductor; it then leaves by the narrow part of the conductor by
means of which part the rove is guided to the nip of the drawing
rollers, The rove is, of course, drafted or drawn out between the
retaining and drawing rollers according to the draft required, and
the fibrous material, now in thread size is placed in a slot of the
"thread-plate," then round the top of the flyer, round one of the
arms of the flyer, through the eye or palm at the end of the flyer
arm and on to the spinning bobbin. The latter is raised and lowered
as in the roving frame by a builder motion, so that the yarn may be
distributed over the full range between the ends or flanges.
Each spindle is driven separately by means of a tape or band which
passes partially round the driving cylinder and the driven whorl of
the spindle, and a constant relation obtains between the delivery of
the yarn and the speed of the spindle during the operation of
spinning any fixed count or type of yarn. In this connection, the
parts resemble those in the roving frame, but from this point the
functions of the two frames differ. The yarn has certainly to be
wound upon the bobbin and at the same rate as it is delivered from
the drawing or delivery rollers, but in the spinning frame the bobbin,
which rotates on the spindle, is not driven positively, as in the
roving frame, by wheel gearing; each spinning bobbin is actually
driven by the yarn being pulled round by the arm of the flyer and
just sufficient resistance is offered by the pressure or tension of
the "temper band" and weight. The temper band is simply a piece of
leather or hemp twine to which is attached a weight, and the other
end of the leather or twine is attached to the builder rail.
[Illustration: FIG. 21 A LINE OF SPINNING FRAMES]
The front part of the builder rail is provided with grooves into one
of which the temper-band is placed so that the band itself is in
contact with a groove near the base of the bobbin flange. A varying
amount of resistance or tension on the bobbin is required in virtue
of the varying size of the partially-filled bobbin, and this is
obtained by placing the temper-band successively in different groves
in the builder so that it will embrace a gradually increasing arc of
the spinning bobbin, and thus impart a heavier drag or tension.
The spinning frames in Fig. 20 are arranged with the ends of the
frame parallel to the pass, whereas the end frames in Fig. 21 are at
right angles to the pass, and hence an excellent view of the chief
parts is presented. The full rove bobbins are seen distinctly on the
pegs of the creel in the upper part of the figure, and the rove
yarns from these bobbins pass downwards, as already described, until
they ultimately enter the eyes of the flyer arms to be directed to
and wound upon the spinning bobbins. The flyers--at one time termed
throstles--are clearly visible a little above the row of temper
weights. The chief parts for raising the builder--cam lever,
adjustable rod, chain and wheel--are illustrated at the end of the
frame nearest the observer.
CHAPTER XI. TWISTING AND REELING
In regard to cloth manufacture, most yarns are utilized in the form
they leave the spinning frame, that is, as single yarns. On the
other hand, for certain branches of the trade, weaving included, it
is necessary to take two, three, or more of these single yarns and to
combine them by a process technically termed twisting, and sometimes
"doubling" when two single yarns only are combined.
Although the commonest method, so far as weaving requirements go, is
to twist two single yarns together to make a compound yarn, it is
not uncommon to combine a much higher number, indeed, sixteen or
more single yarns are often united for special purposes, but, when
this number is exceeded, the operation comes under the heading of
twines, ropes and the like. The twist or twine thus formed will have
the number of yarns regulated by the levelness and strength required
for the finished product. The same operation is conducted in the
making of strands for cordage, but when a number of these twines are
laid-up or twisted together, the name cord or rope is used to
distinguish them.[1]
[Footnote 1: See _Cordage and Cordage Hemp and Fibres_, by T.
Woodhouse and P. Kilgour.]
When two or three threads are united by twisting, the operation can
be conducted in a twisting frame which differs little from a
ordinary spinning frame, and hence need not be described. There may
be, however, appliances embodying some system of automatic stop
motion to bring the individual spindles to rest if one thread out of
any group which are being combined happens to break. When several
threads have to be twisted together, special types of twisting
frames are employed; these special machines are termed "tube twisters,"
and the individual threads pass through holes suitably placed in a
plate or disc before they reach the tube.
More or less elaborate methods of combining yarns are occasionally
adopted, but the reader is advised to consult the above-mentioned
work on Cordage and similar literature for detailed information.
When the yarn leaves the spinning frame, or the twisting frame, it
is made up according to requirements, and the general operations
which follow spinning and twisting are,--reeling, cop-winding, roll
or spool winding, mill warping or link warping. The type or class of
yarn, the purpose for which the yarn is to be used, or the equipment
of the manufacturer, determines which of these methods should be
used previous to despatching the yarn.
_Reeling_. Reeling is a comparatively simple operation, consisting
solely of winding the yarns from the spinning or twisting bobbins on
to a wide swift or reel of a suitable width and of a fixed diameter,
or rather circumference. Indeed, the circumference of the reel was
fixed by an Act of Convention of Estates, dating as far back as 1665
and as under:
"That no linen yarn be exported under the pain of confiscation, half
to the King and half to the attacher."
"That linen yarn be sold by weight and that no reel be shorter than
_ten quarters_."
The same size of reel has been adopted for all jute yarns. All such
yarns which are to be dyed, bleached, or otherwise treated must be
reeled in order that the liquor may easily penetrate the threads
which are obviously in a loose state. There are systems of dyeing
and bleaching yarns in cop, roll or beam form, but these are not
employed much in the jute industry. Large quantities of jute yarns
intended for export are reeled, partly because bundles form suitable
bales for transport, and partly because of the varied operations and
sizes of apparatus which obtain in foreign countries.
YARN TABLE FOR JUTE YARNS
90 inches, or 2-1/2 yards = 1 thread, or
the circumference of the reel
120 threads or 300 yards = 1 cut (or lea)
2 cuts or 600 yards = 1 heer
12 cuts or 3,600 yards = 1 standard hank
48 cuts or 14,400 yards = 1 spyndle
Since jute yarns are comparatively thick, it is only the very finest
yarns which contain 12 cuts per hank. The bulk of the yarn is made
up into 6-cut hanks. If the yarn should be extra thick, even 6 cuts
are too many to be combined, and one finds groups of 4 cuts, 3 cuts,
2 cuts, and even 1 cut. A convenient name for any group less than 12
cuts is a "mill-hank," because the number used is simply one of
convenience to enable the mill-hank to be satisfactorily placed on
the swift in the winding frame.
The reeling operation is useful in that it enables one to measure
the length of the yarn; indeed, the operation of reeling, or forming
the yarn into cuts and hanks, has always been used as the method of
designating the count, grist or number of the yarn. We have already
seen that the count of jute yarn is determined by the weight in lbs.
of one spyndle (14,400 yds.).
For 8 lb. per spyndle yarn, and for other yarns of about the same
count, it is usual to have provision for 24 spinning bobbins on the
reel. As the reel rotates, the yarn from these 24 bobbins is wound
round, say,
6 in. apart, and when the reel has made 120 revolutions, or 120
threads at each place from each bobbin, there will be 24 separate
cuts of yarn on the reel. When 120 threads have been reeled as
mentioned, a bell rings to warn the attendant that the cuts are
complete; the reel is then stopped, and a "lease-band" is tied round
each group of 120 threads.
A guide rod moves the thread guide laterally and slowly as the
reeling operation is proceeding so that each thread or round may be
in close proximity to its neighbour without riding on it, and this
movement of the thread extends to approximately 6 in., to accommodate
the 6 cuts which are to form the mill-hank.
Each time the reel has made 120 revolutions and the bell rings, the
reeler ties up the several cuts in the width, so that when the
mill-hank is complete, each individual cut will be distinct. In some
case, the two threads of the lease-band instead of being tied, are
simply crossed and recrossed at each cut, without of course breaking
the yarn which is being reeled, although effectively separating the
cuts. At the end of the operation (when the quantity of cuts for the
mill-hank has been reeled) the ends of the lease-band are tied.
The object of the lease-band is for facilitating the operation of
winding, and for enabling the length to be checked with approximate
correctness.
When the reel has been filled with, say, twenty-four 6-cut hanks,
there will evidently be 3 spyndles of yarn on the reel. The 24
mill-hanks are then slipped off the end of the reel, and the hanks
taken to the bundling stool or frame. Here they, along with others
of the same count, are made up into bundles which weigh from 54 lb.
to 60 lb. according to the count of the yarn. Each bundle contains a
number of complete hanks, and it is unusual to split a hank for the
purpose of maintaining an absolutely standard weight bundle. Indeed,
the bundles contain an even number of hanks, so that while there
would be exactly 56 lb. per bundle of 7 lb. yarn, or 8 lb. yarn,
there would be 60 lb in a bundle of 7-1/2 lb. yarn, and 54 lb.
in a bundle of 9 lb. yarn.
The chief point in reeling is to ensure that the correct number of
threads is in each cut, i.e. to obtain a "correct tell"; this ideal
condition may be impracticable in actual work, but it is wise to
approach it as closely as possible. Careless workers allow the reel
to run on after one or more spinning bobbins are empty, and this
yields what is known as "short tell." It is not uncommon to
introduce a bell wheel with, say, 123 or 124 teeth, instead of the
nominal 120 teeth, to compensate for this defect in reeling.
CHAPTER XII. WINDING: ROLLS AND COPS
The actual spinning and twisting operations being thus completed,
the yarns are ready to be combined either for more elaborate types
of twist, or for the processes of cloth manufacture. In its simplest
definition, a fabric consists of two series of threads interlaced in
such way as to form a more or less solid and compact structure. The
two series of threads which are interlaced receive the technical
terms of warp and weft--in poetical language, warp and woof. The
threads which form the length of the cloth constitute the warp,
while the transverse threads are the weft.
The warp threads have ultimately to be wound or "beamed" on to a
large roller, termed a weaver's beam, while the weft yarn has to be
prepared in suitable shape for the shuttle. These two distinct
conditions necessitate two general types of winding:
(_a_) Spool winding or bobbin winding for the warp yarns.
(_b_) Cop winding or pirn winding for the weft yarns.
For the jute trade, the bulk of the warp yarn is wound from the
spinning bobbin on to large rolls or spools which contain from 7 to
8 lb. of yarn; the weft is wound from the spinning bobbin into cops
which weigh approximately 4 to 8 ounces.
Originally all jute yarns for warp were wound on to flanged bobbins
very similar to, but larger than, those which are at present used
for the linen trade. The advent of the roll-winding machine marked a
great advance in the method of winding warp yarns as compared with
the bobbin winding method; indeed, in the jute trade, the latter are
used only for winding from hank those yarns which have been bleached,
dyed or similarly treated. Fig. 22 illustrates one of the modern
bobbin winding machines for jute made by Messrs. Charles Parker,
Sons & Co., Dundee. The finished product is illustrated by two full
bobbins on the stand and close to a single empty bobbin. There are
also two full bobbins in the winding position, and several hanks of
yarn on the swifts. Each bobbin is driven by means of two discs, and
since the drive is by surface contact between the discs and the
bobbin, an almost constant speed is imparted to the yarn throughout
the process. An automatic stop motion is provided for each bobbin;
this apparatus lifts the bobbin clear of the discs when the bobbin
is filled as exemplified in the illustration.
The distance between the flanges of the bobbin is, obviously, a
fixed one in any one machine, and the diameter over the yarn is
limited. On the other hand, rolls may be made of varying widths and
any suitable diameter. And while a bobbin holds about 2 lb. of yarn,
a common size of roll weighs, as already stated, from 7 to 8 lb.
Such a roll measures, about 9 in. long and 8 in. diameter; hence for
8 lb. yarn, the roll capacity is 14,400 yards.
Rolls very much larger than the above are made on special machines
adopted to wind about six rolls as shown in Fig. 23. It is built
specially for winding heavy or thick yarns into rolls of 15 in.
diameter and 14 in. length, and this particular machine is used
mostly by rope makers and carpet manufacturers. One roll only is
shown in the illustration, and it is winding the material from a 10
in. x 5 in. rove bobbin. The rove is drawn forward by surface or
frictional contact between the roll itself and a rapidly rotating
drum. The yarn guide is moved rapidly from side to side by means of
the grooved cam on the left, the upright lever fulcrumed near the
floor, and the horizontal rod which passes in front of the rolls and
upon which are fixed the actual yarn guides. This rapid traverse,
combined with the rotation of the rolls, enables the yarn to be
securely built upon a paper or wooden tube; no flanges are required,
and hence the initial cost as well as the upkeep of the foundations
for rolls is much below that for bobbins.
[Illustration: _By permission of Messrs. Charles Parker, Sons & Co_.
FIG. 22 BOBBIN WINDING MACHINE WITH HANKS]
Precisely the same principles are adopted for winding the ordinary 9
in. x 8 in. or 8 in. x 7 in. rolls for the warping and dressing
departments. These rolls are made direct from the yarn on spinning
bobbins, but the machines are usually double-sided, each side having
two tiers; a common number of spools for one machine is 80.
The double tier on each side is practicable because of the small
space required for the spinning bobbins. When, however, rolls are
wound from hank, as is illustrated in Fig. 24, and as practised in
several foreign countries even for grey yarn, one row only at each
side is possible. Both types are made by each machine maker, the one
illustrated in Fig. 24 being the product of Messrs. Charles Parker,
Sons & Co., Dundee.
In all cases, the yarns are built upon tubes as mentioned, the
wooden ones weighing only a few ounces and being practically
indestructible, besides being very convenient for transit; indeed it
looks highly probable that the use of these articles will still
further reduce the amount of yarn exported in bundle form.
[Illustration: FIG. 23 ROLL WINDER FOR LARGE ROLLS _By permission of
Messrs. Douglas Fraser & Sons, Ltd_.]
The machine illustrated in Fig. 24, as well as those by other makers,
is very compact, easily adjustable to wind different sizes of rolls,
can be run at a high speed, and possesses automatic stop motions,
one for each roll.
A full roll and a partially-filled roll are clearly seen. A recent
improvement in the shape of a new yarn drag device, and an automatic
stop when the yarn breaks or the yarn on the bobbin is exhausted,
has just been introduced on to the Combe-Barbour frame.
[Illustration: FIG. 24 ROLL WINDING MACHINE (FROM HANKS) _By
permission of Messrs. Charles Parker, Sons & Co_.]
Weft Winding. A few firms wind jute weft yarn from the spinning
bobbins on to pirns (wooden centres). The great majority of
manufacturers, however, use cops for the loom shuttles. The cops are
almost invariably wound direct from the spinning bobbins, the
exception being coloured yarn which is wound from hank. There are
different types of machines used for cop winding, but in every case
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