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THE JUTE INDUSTRY
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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.
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.).
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.
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".
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 the yarn is wound upon a bare spindle, and the yarn guide has a rapid traverse in order to obtain the well-known cross-wind so necessary for making a stable cop. The disposition of the cops in the winding operation is vertical, but while in some machines the tapered nose of the cop is in the high position and the spinning bobbin from which the yarn is being drawn is in the low position, in other machines these conditions are opposite. Thus, in the cop winding frame made by Messrs. Douglas Fraser & Sons, Ltd., Arbroath, and illustrated in Fig. 25, the spinning bobbins are below the cops, the tapered noses of the latter are upwards in their cones or shapers, and the yarn guides are near the top of the machine. This view shows about three-fourths of the full width of a 96-spindle machine, 48 spindles on each side, two practically full-length cops and one partially built. The illustration in Fig. 26 is the above-mentioned opposite type, and the one most generally adopted, with the spinning bobbins as shown near the top of the frame, the yarn guides in the low position, and the point or tapered nose of the cop pointing downwards. Six spindles only appear in this view, which represents the machine made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, but it will be understood that all machines are made as long as desired within practicable and economic limits. |
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