The Jute Industry: From Seed to Finished Cloth Part 7

_G_ is a "herring-bone" design on 24 threads and 4 picks, two units shown. It is typical of the pattern represented at _C_, Fig. 32, and involves the use of 4 leaves in the loom.

The solid squares in weave _A_, Fig. 33, are reproduced in the left-hand bottom corner of Fig. 34. A diagrammatic plan of a plain cloth produced by this simple order of interlacing is exhibited in the upper part by four shaded threads of warp and four black picks of weft (the difference is for distinction only). The left-hand intersection shows one thread interweaving with all the four picks, while the bottom intersection shows all the four threads interweaving with one pick. The two arrows from the weave or design to the thread and pick respectively show the connection, and it will be seen that a mark (solid) on the design represents a warp thread on the surface of the cloth, while a blank square represents a weft shot on the surface, and _vice versa_.

A weaving shed full of various types of looms, and all driven by belts from an overhead shaft, is ill.u.s.trated in Fig. 35. The loom in the foreground is weaving a 3-leaf sacking similar to that ill.u.s.trated at _S_, Fig. 32. while the appearance of a full weaver's warp beam is shown distinctly in the second loom in Fig. 35. There are hundreds of looms in this modern weaving shed.

[Ill.u.s.tration: FIG. 35 WEAVING SHED WITH BELT-DRIVEN LOOMS]

During the operation of weaving, the shuttle, in which is placed a cop of weft, similar to that on the cop winding machine in Fig. 25, and with the end of the weft threaded through the eye of the shuttle, is driven alternately from side to side of the cloth through the opening or "shed" formed by two layers of the warp. The positions of the threads in these two layers are represented by the designs, see Fig. 33, and while one layer occupies a high position in the loom the other layer occupies a low position. The threads of the warp are placed in these two positions by the leaves of the camb (termed healds and also gears in other districts) and it is between these two layers that the shuttle pa.s.ses, forms a selvage at the edge each time it makes a journey across, and leaves a trail or length of weft each journey. The support or lay upon which the shuttle travels moves back to provide room for the shuttle to pa.s.s between the two layers of threads, and after the shuttle reaches the end of each journey, the lay with the reed comes forward again, and thus pushes successively the shots of weft into close proximity with the ones which preceded.

[Ill.u.s.tration: FIG. 36 LOOMS DRIVEN WITH INDIVIDUAL MOTORS _By permission of The English Electric Co., Ltd._]

The order of lifting and depressing the threads of the warp is, as already stated, demonstrated on the design paper in Fig. 33, and the selected order determines, in the simplest cases, the pattern on the surface of the cloth when the warp and weft yarns are of the same colour. A great diversity of pattern can be obtained by the method of interlacing the two sets of yarn, and a still greater variety of pattern is possible when differently-coloured threads are added to the mode of interlacing.

To ill.u.s.trate the contrast in the general appearance of a weaving shed in which all the looms are driven by belts from overhead shafting as in Fig. 35, and in a similar shed in which all the looms are individually driven by small motors made by the English Electric Co., Ltd. we introduce Fig. 36. This particular ill.u.s.tration shows cotton weaving shed, but precisely the same principle of driving is being adopted in many jute factories.

A great variety of carpet patterns of a similar nature to that ill.u.s.trated at C, Fig. 32, can be woven in looms such as those ill.u.s.trated in Fig. 35; indeed, far more elaborate patterns than that mentioned and ill.u.s.trated are capable of being produced in these comparatively simple looms. When, however, more than 4 leaves are required for the weaving of a pattern, a dobby loom, of the nature of that shown in Fig. 37, is employed; this machine is made by Messrs. Charles Parker, Sons & Co., Ltd., Dundee. The dobby itself, or the apparatus which lifts the leaves according to the requirements of the design, is fixed on the upper part of the frame-work, and is designed to control 12 leaves, that is, it operates 12 leaves, each of which lifts differently from the others.

[Ill.u.s.tration: _By permission of Messrs. Charles Parker, Sons & Co_.

FIG. 37 DOBBY LOOM]

A considerable quant.i.ty of Wilton and Brussels carpets is made from jute yarns, and Fig. 38 ill.u.s.trates a loom at work on this particular branch of the trade. The different colours of warp for forming the pattern me from small bobbins in the five frames at the back of the loom (hence the term 5-frame Brussels or Wilton carpet) and the ends pa.s.sed through "mail eyes" and then through the reed.

The design is cut on the three sets of cards suspended in the cradles in the front of the loom, and these cards operate on the needles of the jacquard machine to raise those colours of yarn which e necessary to produce the colour effect in the cloth t correspond with the colour effect on the design paper made by the designer.

This machine weaves the actual Brussels and Wilton fabrics, and these cloths are quite different from that ill.u.s.trated at _P_, Fig.

32. In both fabrics, however, ground or foundation warps are required. It need hardly be said that there is a considerable difference between the two types of cloth, as well as between the designs and the looms in which they are woven.[2]

[Footnote 2: For structure of carpets, _see_ pp. 394-114, _Textile Design: Pure and Applied_, by T. Woodhouse and T. Milne.]

[Ill.u.s.tration: FIG. 38 BRUSSELS CARPET JACQUARD LOOM]

In the weaving department there are heavy warp beams to be placed in the looms, and in the finishing department there are often heavy rolls of cloth to be conveyed from the machines to the despatch room.

Accidents often happen when these heavy packages, especially the warp beams, are being placed in position. In order to minimize the danger to workpeople and to execute the work more quickly and with fewer hands, some firms have installed Overhead Runway Systems, with suitable Lifting Gear, by means of which the warp beams are run from the dressing and drawing-in departments direct to the looms, and then lowered quickly and safely into the bearings. Such means of transport are exceedingly valuable where the looms are set close to each other and where wide beams are employed; indeed, they are valuable for all conditions, and are used for conveying cloth direct from the looms as well as warp beams to the looms. Fig. 39 shows the old wasteful and slow method of transferring warp beams from place to place, while Fig. 40 ill.u.s.trates the modern and efficient method.

The latter figure ill.u.s.trates one kind of apparatus, supplied by Messrs. Herbert Morris, Ltd., Loughborough, for this important branch of the industry.

[Ill.u.s.tration: FIG. 39. THE OLD WAY]

[Ill.u.s.tration: FIG. 40. THE NEW WAY _By permission of Messrs.

Herbert Morris, Ltd_.]

CHAPTER XV. FINISHING

The finishing touches are added to the cloth after the latter leaves the loom. The first operation is that of inspecting the cloth, removing the lumps and other undesirables, as well as repairing any damaged or imperfect parts. After this, the cloth is pa.s.sed through a cropping machine the function of which is to remove all projecting fibres from the surface of the cloth, and so impart a clean, smart appearance. It is usual to crop both sides of the cloth, although there are some cloths which require only one side to be treated, while others again miss this operation entirely.

A cropping machine is shown in the foreground of Fig. 41, and in this particular case there are two fabrics being cropped or cut at the same time; these happen to be figured fabrics which have been woven in a jacquard loom similar to that ill.u.s.trated in Fig. 38. The fabrics are, indeed, typical examples of jute Wilton carpets. The ill.u.s.tration shows one of the spiral croppers in the upper part of the machine in Fig. 41. Machines are made usually with either two or four of such spirals with their corresponding fixed blades.

[Ill.u.s.tration: FIG. 41 CROPPING MACHINE AT WORK]

The cloth is tensioned either by threading it over and under a series of stout rails, or else between two in a specially adjustable arrangement by means of which the tension may be varied by rotating slightly the two rails so as to alter the angle formed by the cloth in contact with them. This is, of course, at the feed side; the cloth is pulled through the machine by three rollers shown distinctly on the right in Fig. 42. This view ill.u.s.trates a double cropper in which both the spirals are controlled by one belt. As the cloth is pulled through, both sides of it are cropped by the two spirals.[3] When four spirals are required, the frame is much wider, and the second set of spirals is identical with those in the machines ill.u.s.trated.

[Ill.u.s.tration: FIG 42 DOUBLE CROPPING MACHINE _By permission of Messrs. Charles Parker, Sons & Co., Ltd_.]

[Footnote 3: For a full description of all finishing processes, see _The Finishing of Jute and Linen Fabrics_, by T. Woodhouse.

(Published by Messrs. Emmott & Co., Ltd., Manchester.)]

The cropped cloth is now taken to the clamping machine, and placed on the floor on the left of the machine ill.u.s.trated in Fig. 43, which represents the type made by Messrs. Charles Parker, Sons &, Co., Dundee. The cloth is pa.s.sed below a roller near to the floor, then upwards and over the middle roller, backwards to be pa.s.sed under and over the roller on the left, and then forwards to the nip of the pulling rollers, the bottom one of which is driven positively by means of a belt on the pulleys shown. While the cloth is pulled rapidly through this machine, two lines of fine jets spray water on to the two sides of the fabric to prepare it for subsequent processes in which heat is generated by the nature of the finishing process.

At other times, or rather in other machines, the water is distributed on the two sides of the cloth by means of two rapidly rotating brushes which flick the water from two rollers rotating in a tank of water at a fixed level. In both cases, both sides of the fabric are "damped," as it is termed, simultaneously. The damped fabric is then allowed to lie for several hours to condition, that is, to enable the moisture to spread, and then it is taken to the calender.

[Ill.u.s.tration: _By permission of Messrs. Charles Parker, Sons & Co., Ltd_. FIG. 43 DAMPING MACHINE]

The calenders for jute almost invariably contain five different rollers, or "bowls," as they are usually termed; one of these bowls, the smallest diameter one, is often heated with steam. A five-bowl calender is shown on the extreme right in Fig. 41, and in the background, while a complete ill.u.s.tration of a modern 5-bowl calender, with full equipment, and made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, appears in Fig. 44.

[Ill.u.s.tration: _By permission of Messrs. Urquhart, Lindsay & Co., Ltd_.

FIG. 44 CALENDAR]

The cloth is placed on the floor between the two distinct parts of the calender, threaded amongst the tension rails near the bottom roller or bowl, and then pa.s.sed over two or more of the bowls according to the type of finish desired. For calender finish, the bowls flatten the cloth by pressing out the threads and picks, so that all the interstices which appear in most cloths as they leave the loom, and which are exaggerated in the plan view in Fig. 34, are eliminated by this calendering action. The cloth is then delivered at the far side of the machine in Fig. 44. If necessary, the surface speed of the middle or steam-heated roller may differ from the others so that a glazed effect--somewhat resembling that obtained by ordinary ironing--is imparted to the surface of the fabric. The faster moving roller is the steam-heated one. For ordinary calender finish, the surface speed of all the rollers is the same.

Another "finish" obtained on the calender is known as "chest finish"

or "round-thread finish." In this case, the whole length of cloth is wound either on to the top roller, or the second top one, Fig. 44, and while there is subjected to the degree of pressure required; the amount of pressure can be regulated by the number of weights and the way in which the tension belt is attached to its pulley. The two sets of weights are seen clearly on the left in Fig. 44, and these act on the long horizontal levers, usually to add pressure to the dead weight of the top roller, but occasionally, for very light finishes, to decrease the effective weight of the top bowl. After the cloth has been chested on one or other of the two top bowls, it is stripped from the bowl on to a light roller shown clearly with its belt pulley in Fig. 41.

There are two belt pulleys shown on the machine in Fig. 44; one is driven by an open belt, and the other by a crossed belt. Provision is thus made for driving the calender in both directions. The pulleys are driven by two friction clutches, both of which are inoperative when the set-on handle is vertical as in the figure.

Either pulley may be rotated, however, by moving the handle to a oblique position.

The compound leverage imparted to the bearings of the top bowl, and the weights of the bowls themselves, result in the necessary pressure, and this pressure may be varied according to the number of small weights used. The heaviest finish on the calender, i.e. the chest-finish on the second top roller, imitates more or less the "mangle finish."

[Ill.u.s.tration: _By permission of Messrs. Urquhart, Lindsay & Co., Ltd_.

FIG. 45 HYDRAULIC MANGLE]

A heavy hydraulic mangle with its acc.u.mulator and made by Messrs.

Urquhart, Lindsay & Co., Ltd., Dundee, is ill.u.s.trated in Fig. 45.

The cloth is wound or beamed by the mechanism in the front on to what is termed a "mangle pin"; it is reality a thick iron bowl; when the piece is beamed, it is automatically moved between two huge rollers, and hydraulic pressure applied. Four narrow pieces are shown in Fig. 45 on the pin, and between the two rollers. There are other four narrow pieces, already beamed on another pin, in the beaming position, and there is still another pin at the delivery side with a similar number of cloths ready for being stripped. The three pins are arranged thus oo, and since all three are moved simultaneously, when the mangling operation is finished, each roller or pin is moved through 120. Thus, the stripped pin will be placed in the beaming position, the beamed pin carried into the mangling position, and the pin with the mangled cloth taken to the stripping position.

While the operation of mangling is proceeding, the rollers move first in one direction and then in the other direction, and this change of direction is accomplished automatically by mechanism situated between the acc.u.mulator and the helical-toothed gearing seen at the far end of the mangle. And while this mangling is taking place, the operatives are beaming a fresh set, while the previously mangles pieces are being stripped by the plaiting-down apparatus which deposits the cloth in folds. This operation is also known as "cuttling" or "faking." It will be, understood that a wide mangle, such as that ill.u.s.trated in Fig. 45. is constructed specially for treating wide fabrics, and narrow fabrics are mangled on it simply because circ.u.mstances and change of trade from time to time demand it.

[Ill.u.s.tration: _By permission of Messrs. Charles Parker, Sons & Co.

Ltd_. Fig 46 FOLDING, LAPPING OR PLEATING MACHINE]

The high structure on the left is the acc.u.mulator, the manipulation of this and the number of wide weights which are ingeniously brought into action to act on the plunger determine the pressure which is applied to the fabrics between the bowls or rollers.

Cloths both from the calender and the mangle now pa.s.s through a measuring machine, the clock of which records the length pa.s.sed through. There are usually two hands and two circles of numbers on the clock face; one hand registers the units up to 10 on one circle of numbers, while the slower-moving hand registers 10, 20, 30, up to 100. The measuring roller in these machines is usually one yard in circ.u.mference.

If the cloth in process of being finished is for use as the backing or foundation of linoleum, it is invariably wound on to a wooden centre as it emerges from the bowls of the calender, measured as well, and the winding-on mechanism is of a friction drive somewhat similar to that mentioned in connection with the dressing machine. Cloths for this purpose are often made up to 600 yards in length; indeed, special looms, with winding appliances, have been constructed to weave cloths up to 2,000 yards in length. Special dressing machines and loom beams have to be made for the latter kind. When the linoleum backing is finished at the calender, both cloth and centre are forwarded direct to the linoleum works. The empty centres are returned periodically.

Narrow-width cloths are often made up into a roll by means of a simple machine termed a calenderoy, while somewhat similar cloth, and several types of cloths of much wider width, are lapped or folded by special machines such as that ill.u.s.trated in Fig. 46. The cloth pa.s.ses over the oblique board, being guided by the discs shown, to the upper part of the carrier where it pa.s.ses between the two bars.

As the carrier is oscillated from side to side (it is the right hand side in the ill.u.s.tration) the cloth is piled neatly in folds on the convex table. The carriers may be adjusted to move through different distances, so that any width or length of fold, between limits, may be made.

Comparatively wide pieces can be folded on the above machine, but some merchants prefer to have wide pieces doubled lengthwise, and this is done by machines of different kinds. In all cases, however, the operation is termed "crisping" in regard to jute fabrics. Thus, Fig. 47, ill.u.s.trates one type of machine used for this purpose, and made by Messrs. Urquhart, Lindsay & Ca., Ltd., Dundee. The full-width cloth on the right has obviously two prominent stripes--one near each side. The full width cloth pa.s.ses upwards obliquely a triangular board, and when the cloth reaches the apex it is doubled and pa.s.sed between two bars also set obliquely on the left.