(30) It being highly desirable that the naturally open fleecy condition of the cotton shall be restored at the earliest moment, the question arises, What shall be the draught of the bale breaker rollers? Is it necessary to do more than break up the lumps of cotton into smaller pieces, which can be readily treated by the subsequent machines? To these questions different answers are given. On the one hand, it is contended that what is required is to reproduce the conditions of hand breaking, by which the cotton was pulled from the bales in small tufts ready for delivery to the opening machinery. Another practice advocated is to so pull the lumps into which the bale is broken up that the cotton when delivered is in an open fleecy condition. It would be preferred by spinners if they could obtain the cotton in the loosely packed condition in which it is received by the Indian spinners, for instance. As this cannot be done, owing to commercial and transit considerations, the question arises whether the first stage in the processes conducted in this country is not the right one to restore this condition.
(31) Between the two positions formulated there is a wide divergence, but, to the author, the latter appears to possess the balance of advantage. There can be no doubt that the preparation of the fibre cannot be commenced at too early a stage, and, as efficient cleansing is one of the first objects to be attained, it follows that the earlier the open condition of the cotton is reached the more readily can cleaning be effected. It must not be forgotten that care is necessary to avoid possible damage to the fibres, but, with rollers properly speeded, there appears to be no reason to expect such a result.
(32) In consequence of the divergent views held, the draught of a bale breaker varies considerably. In some cases it is only 2: 1, while in others it reaches 30: 1. The former is the rule adopted by Messrs. Crighton and Sons, who advocate the first course named, and the latter that adopted by Messrs. Lord Brothers, who prefer the second. Messrs. Platt Brothers and Company recommend a wise variation in this respect, proceeding upon the principle that different staples require different treatment. Thus one machine made by them has four rollers with a large draught, this being used for good staples, and producing as much as 90,000lbs. weight in 50 hours. In dealing with Surat cotton, which is more hardly pressed, two sets of rollers are used, followed by a beating cylinder by which the cotton is thoroughly broken up (Fig. [8]). In each case it is customary to attach lattices to the machine, by which the cotton is carried forward and deposited in the mixing bins (E Fig. [13]). (See also Figs. [6], [7], and [8]). Another method is to treat Surat cotton by first passing it through breaker rollers, and thence through a Crighton cylinder, described in Chapter [IV]. The bale breaker may in this case be used either singly or as part of the combination.
(33) The rollers are made in two ways. They are cast in one piece and are mounted upon the shaft; or are built up from a number of discs threaded and fastened upon the shaft and bolted together. The latter is the preferable course, the breakage of a few teeth being easily remedied.
Fig. 5.J.N.
(34) Before proceeding further, reference may be made to Fig. [5], which is a transverse section of the machine as made by Messrs. Dobson and Barlow. The top rollers of the machine, as ordinarily made, are provided with spring weighting, in order to permit them to rise if an unusually large piece of cotton is passed between them. If this enters at one side of the machine it will be at once seen that the roller will be raised at that side, and that its axis will be angularly disposed to that of the bottom roller. The two rollers will only be near each other at one side, and between them, across the whole of the width of the machine, will be a gradually increasing space through which lumps of cotton can pass unpulled. This is a defect of more or less magnitude, but is one which is ingeniously remedied in the machine shown in Fig. [5]. Only one line of rollers, marked U V Y Z, is used, by two of which the pulling is effected. Below these the noses of iron bars or levers, Q R, fulcrumed on knife edges, are placed. The bars are a few inches wide, and extend below the rollers over their entire width. The cotton passes over these “pedal” levers, which are weighted at their other end, and yield, as shown by the dotted lines, when an extra large piece of cotton passes. The weight is sufficient to enable the cotton to be held until it is pulled by the roller. It will be at once seen that only the pedals affected by the lump will be depressed, the remainder occupying their normal relative position to the roller, which is fixed by the stop shown. In this way the presence of a thick piece at one point in the width of the rollers does not affect the pulling at another point.
Fig. 6.J.N.
