The Jute Industry: From Seed to Finished Cloth

by Thomas Woodhouse; Peter Kilgour

FIG. 30 A MODERN YARN DRESSING MACHINE WITH SIX STEAM-HEATED CYLINDERS

A different way of arranging the cylinders is exemplified in Fig. 31. This view, which illustrates a machine made by Messrs. Charles Parker, Sons & Co., Dundee, has been introduced to show that if the warps under preparation contain a comparatively few threads, or if the banks are made larger than usual, two warps may be dressed at the same time. In such a case, three cylinders only would be used for each warp, and the arrangement would be equivalent to two single dressing machines. The two weaver's beams, with their pressing rollers, are shown plainly in the centre of the illustration. Some machines have four cylinders, others have six, while a few have eight. A very similar machine to that illustrated in Fig. 31 is made so that all the six cylinders may be used to dry yarns from two banks, and all the yarns wound on to one weaver's beam, or all the yarns may be wound on to one of the beams in the machine in Fig. 31 if the number of threads is too many for one bank.

FIG. 31 DRESSING MACHINE FOR PREPARING TWO WARPS SIMULTANEOUSLY
By permission of Messrs. Charles Parker, Sons & Co.

Suppose it is desired to make a warp of 700 threads instead of 500, as in the above example; then 350 spools would be placed in each of the two banks, the threads disposed as already described to use as much of the heating surface of the cylinder as possible, and one sheet of threads passed partially round what is known as a measuring roller. Both sheets of threads unite into one sheet at the centre of the machine in Fig. 31, and pass in this form on to one of the loom beams.

It has already been stated that the lower roller in the starch box is positively driven by suitable mechanism from the central part of the machine, Fig. 29, while the upper roller, see Fig. 30, is a pressing roller and is covered with cloth, usually of a flannel type. Between the two rollers the sheet of 350 threads passes, becomes impregnated with the starch which is drawn up by the surface of the lower roller, and the superfluous quantity is squeezed out and returns to the trough, or joins that which is already moving upwards towards the nip of the rollers. The yarn emerges from the rollers and over the cylinders at a constant speed, which may be chosen to suit existing conditions, and it must also be wound on to the loom beam at the same rate. But since the diameter of the beam increases each revolution by approximately twice the diameter of the thread, it is necessary to drive the beam by some kind of differential motion.

The usual way in machines for dressing jute yarns is to drive the beam support and the beam by means of friction plates. A certain amount of slip is always taking place--the drive is designed for this purpose--and the friction plates are adjusted by the yarn dresser during the operation of dressing to enable them to draw forward the beam, and to slip in infinitesimal sections, so that the yarn is drawn forward continuously and at uniform speed.

During the operation, the measuring roller and its subsequent train of wheels and shafts indicates the length of yarn which has passed over, also the number of "cuts" or "pieces" of any desired length; in addition, part of the measuring and marking mechanism uses an ink-pad to mark the yarn at the end of each cut, such mark to act as a guide for the weaver, and to indicate the length of warp which has been woven. Thus if the above warp were intended to be five cuts, each 120 yards, or 600 yards in all, the above apparatus would measure and indicate the yards and cuts, and would introduce a mark at intervals of 120 yards on some of the threads. And all this is done without stopping the machine. At the time of marking, or immediately before or after, just as desired, a bell is made to ring automatically so that the attendant is warned when the mark on the warp is about to approach the loom beam. This bell is shown in Fig. 29, near the right-hand curved outer surface of the central frame.

As in hand warping or in linking, a single-thread lease is made at the end of the desired length of warp, or else what is known as a pair of "clasp-rods" is arranged to grip the sheet of warp threads.

After the loom beam, with its length of warp, has been removed from the machine, the threads are either drawn through the eyes or mails of the cambs (termed gears, healds or heddles in other districts) and through the weaving reed, or else they are tied to the ends of the threads of the previous warp which, with the weft, has been woven into cloth. These latter threads are still intact in the cambs and reed in the loom.

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[CHAPTER XIV. TYING-ON, DRAWING-IN, AND WEAVING]

If all the threads of the newly-dressed warp can be tied on to the ends of the warp which has been woven, it is only necessary, when the tying-on process is completed, to rotate the loom beam slowly, and simultaneously to draw forward the threads until all the knots have passed through the cambs and the reed, and sufficiently far forward to be clear of the latter when it approaches its full forward, or beating up, position during the operation of weaving.

If, on the other hand, the threads of the newly-dressed, or newly-beamed, warp had to be drawn-in and reeded, these operations would be performed in the drawing-in and reeding department, and, when completed, the loom beam with its attached warp threads, cambs and reed, would be taken bodily to the loom where the "tenter," "tackler" or "tuner" adjusts all the parts preparatory to the actual operation of weaving. The latter work is often termed "gaiting a web."

There is a great similarity in many of the operations of weaving the simpler types of cloth, although there may be a considerable difference in the appearance of the cloths themselves. In nearly all the various branches of the textile industry the bulk of the work in the weaving departments of such branches consists of the manufacture of comparatively simple fabrics. Thus, in the jute industry, there are four distinct types of cloth which predominate over all others; these types are known respectively as hessian, bagging, tarpauling and sacking. In addition to these main types, there are several other simple types the structure of which is identical with one or other of the above four; while finally there are the more elaborate types of cloth which are embodied in the various structures of carpets and the like.

It is obviously impossible to discuss the various makes in a work of this kind; the commoner types are described in Jute and Linen Weaving Calculations and Structure of Fabrics; and the more elaborate ones, as well as several types of simple ones, appear in Textile Design: Pure and Applied, both by T. Woodhouse and T. Milne.

Six distinct types of jute fabrics are illustrated in Fig. 32. The technical characteristics of each are as follows--