The Jute Industry: From Seed to Finished Cloth Part 2

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 cla.s.s 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 cla.s.s 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 ill.u.s.trated 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.

[Ill.u.s.tration: FIG. 8 BALE OPENER _By permission of Messrs. Urquhart, Lindsay & Co., Ltd_.]

The layers of heads are often beaten with a heavy sledge hammer in hand batching, but for machine batching a bale opener is used, and this operation const.i.tutes 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 crus.h.i.+ng 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 ill.u.s.trated in Fig. 9. It differs mainly from the machine ill.u.s.trated in Fig. 8 in the shape of the crus.h.i.+ng or opening rollers.

It will be seen on referring to the ill.u.s.tration that there are three crus.h.i.+ng rollers, one large central roller on the top and situated between two lower but smaller rollers. Each roller has a series of k.n.o.bs projecting from a number of parallel rings. The k.n.o.bs 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 pa.s.sing 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.

[Ill.u.s.tration: FIG. 9 BALE OPENER _By permission of Messrs. Charles Parker, Sons, & Co_.]

The driving side, the feed cloth, and the delivery cloth in this machine are placed similarly to the corresponding parts of the machine ill.u.s.trated 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 pa.s.s 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 ma.s.s 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 ill.u.s.trated 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 quant.i.ty.

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 part.i.tion on the right.

[ILl.u.s.tRATION: FIG. 10 HAND-BATCHING DEPARTMENT WITH UNPREPARED AND PREPARED FIBRE]

The first stall--that next to the oil tank--in Fig. 10 is filled with the prepared pieces, and the contents are allowed to remain there for some time, say 24 hours, in order that the material may be more or less uniformly lubricated or conditioned. At the end of this time, the pieces are ready to be conveyed to and fed into the softening machines where the fibres undergo a further process of bending and crus.h.i.+ng.

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 circ.u.mstances and to the opinions of managers. Thus, the softener ill.u.s.trated 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 ill.u.s.tration 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 circ.u.mstances.

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.

[Ill.u.s.tration: Fig. 11 Softening machine without batching apparatus]

Machine batching is preferred by many firms because the application of oil and water, and the proportion of each, are much more uniform than they are by the above mentioned process of hand batching. On the other hand, there is no time for conditioning the fibre because the lubrication and the softening are proceeding simultaneously, although conditioning may proceed while the fibre remains in the cart after it has left the softener.

The mechanical apparatus as made by Messrs. Urquhart, Lindsay & Co., Ltd., Dundee, for depositing the oil and water on the pieces or "stricks" of jute is ill.u.s.trated in Fig. 12. The actual lubricating equipment is situated on the top of the rectangular frame in the centre of the ill.u.s.tration. 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.

[Ill.u.s.tration: Fig. 12]

The water valve is opened and closed with the starting and stopping of the machine, but the oblique rod is moved only when irregular feeding takes place. Thus, the upper rollers rise slightly against the pressure of the springs when thick stricks appear; hence, when a thick place pa.s.ses 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 quant.i.ty 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 ill.u.s.trated 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 pa.s.sed through the machine, and these stricks are now ready for conditioning, and will be stored in a convenient position for future treatment.

[Ill.u.s.tration: Fig. 13 Softening machine with batching apparatus]

While the jute as a.s.sorted and baled for export from India is graded in such a way that it may be used for certain cla.s.ses 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 quant.i.ty 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--