OUR YORKSHIRE LETTER.

Dominion, Volume 4, Issue 969, 9 November 1910, Page 5

OUR YORKSHIRE LETTER.

DEALING WITH BITERS IN WOOLS. (From Ok- Special Correspondent.) Bradford, September 23, 1910. From the many matters exemplifying the saying that tares grow along with wheat wool is by no means an exception. If only the user of wool products could obtain wool and nothing else when buying these commodities his trouble and expense during treatment would be considerably lessened. It is an unfortunate fact that with a fibre finding such considerable employment as wool very often 50 per cent of foreign matter must necessarily be taken which causes considerable delay in the production of the finished material and much additional expense also. Of this extraneous material grease forms a big proportion. Apart from its lnilucnce on weight, however (an influence very difficult to estimate), this is the least troublesome form of impurity, for it has tho effect of preserving the fibre and aiding in the production of a white colour, and moreover it does not'cause considerable trouble when being removed. By far the greater difficulty is experienced with burrs, seeds, and straws, the former especially which are very prevalent in some colonial and South American fleeces, and which have a markedly disadvantageous influence on the condition of the fibre for manufacturing purposes. In wool-using centres news has been brought that the botanists of the colonial Governments have succeeded in finding a plant possessing all the nourishing characteristics of the burr-produc-liig salt bush, but of a type in which the burr is absent. It need hardly be added that could such a plant be developed and substituted for tho present burr type over these great pastoral areas now receiving attention artificially such change would most likely be wrought in the state of the fleece as would-be greatly appreciated by tlmse who meet the inconvenience of removing this alien matter.

A matter, that is not overlooked by the buyer and user of wool is that burrs have an adverse influence on the spinning capacity of the fibre. It is a point also of no less importance for the producer to remember that if bo can grow his wool with fewer or none of these impurities present, or failing this, if he can so classify his lots that the majority of the better material will bo clear of these, a better price will ungrudgingly be paid tor it. For to remove the burr in most cases means breakage of the fibre, this creating additional noil in combing and causing trouble.in the laying of the fibres straightly and smoothly in the top, and so shortening the length as to spoil the spuming quality of the material. On this account burry wool is placed in a low quality position; fine 46's wool, for example, of nice.length lustre and uniformity, but filled with burr needs such severe treatment for tho removal of its impurity as necessitates its depreciation to a quality equal to 40's or under. This means less value in tli'e top—a matter which affects the grower in.that a proportionately less price is paid for the wool. There is no such thing as leaving .the burrs with the wool fibre for the reason that .they are of an altogether different constitution both chemically and physically, from the material with which they are mixed." They are "vegetable," while wool is "animal," and in-charac-teristics of elasticity and flexibility, in fineness and in length, they differ from this material strangely, while more particularly as regards dye-taking property they can only be tinted by the same treatment with which wool is capable of being thoroughly impregnated. They thus show ' specky" in a piece and create a defect which ruins-its sole. Then in whatever way burrs are removed increased cost is incurred as a result of the processes necessary; thus the commission comber, dealing with such wools for worsted purposes, charges Jd. per lb. more for tho top he delivers if such impurity has been to extract. , The woollen, yarn, producer, also, preparing the material for. the carding, condensing, and spinning processes, .'claims extra payment for the additional operations he must-take the material through; then when in addition to the cost of this extra treatment tho injury done to the quality of. the maerial is considered,'.it .will bo seen that the presence of burrs in a,lot is.of far more importance than is apparent at first sight. . . There are two systems available for the removal of burrs from wool. It should bo stated in passing ..that these are far more difficult to clear than, any other' impurity which may be present. Seeds, for example, and straws are usually so brittle that once crushed between rollers under pressure they becomo so dust-like as to be readily cleared away from the material on being shaken. The burr, .on the. other hand, is intertwined among the' fibres, and only a seizing of it as one piece with a subsequent breaking of it away, or the cr.ush.ing of it into numerous parts (an object not easily achieved) can effectively separate it from the fibre by mechanical means, and neither of these can bo accomplished without injury to,tho wool. As another method the chemical process, known as "carbonising," is employed on "clothing" wools; this is altogether too severe for material for combing, purposes for the reason that the fibre is made less lustrous and bright in appearance, and weakened in strength to an extent which makes it. unsuitable for the ■production of a smooth worsted varn. To illustrate this, the procedure adopted in carbonising may be stated. Tho burry material is steeped in sulphuric acid of a strength, say from six to ten degrees Twaddell, or of 1.03 to 1.05 specific gravity, and for a length of time, say thirty minutes. After the draining away of superfluous acid on . specially-arranged scrays, it is subjected to tho high temperature of an oven (190 degrees P.) until the vegetable impurity becomes black and crisp and converted into carbon, which admits of it being readily crushed into dirt. Concentrated sulphuric acid is well known to have a great avidity for moist-' ure, and when brought in contact with the burrs it extracts their moisture constituent and destroys the characteristic features. If now' tho burry material be taken and put through crushing rollers,, a blacK dust mixed with the fibres results, this dust being readily removed by a process of shaking or willeying. Tho drawback to this process is not the result of using acid, but it is-the consequence of the high temperature necessary for that quick concentration on the burrs which will produce a reasonable turn-off. The heat thus applied causes the fibre to shrivel somewhat; the scale also open, and the characteristic harshness and loss of appearance are thereby brought about. The crushing necessary is also injurious to the wool, for the fibres are often [ ground in, too, and consequently made washer. In passing, it should be stated that willeying (to remove the black dust) needs to be done very carefully, for an excess of this will so "rope" the fibres that they will be excessively broken down when treated in the opening process subsequently employed. This process is largely employed on noils—tho woolcombers' by-product. These often contain considerable quantities of burrs, the result of. an attempt in the combing of worsted to free the fibres forming "top from the impurity. Such noils contain oil added to facilitate combing, and consequently the treatment given them does not do so much injury as on less greasy fibres, and being required for purposes such as hat, shawl, and blanket making, in the preparation for which individual fibres will be by no means so much taxed in strength, the drawback to this treatment is not very marked. , The method adopted for worsted on the other hand is mechanical. It consists chiefly of attachments to the carding engino employed in preparing for combing, whereby at the same time as tho fibres are controlled by the pins of that machine, the burrs standing in the range of. action of a special burr beater are forced away. For only partially burrv wcols a six-blade<l roller working on the ordinary clothing of the carder at GOO revolutions per minute will suffice for the clothing of the carder being set 100 donsely to allow of tlw penetration of a burr below tho surface of its teeth, the burr roller being very effective in blatiV the burrs away into trays. It should be stated, however, that in this case with each burr there usually comes an amount of fibre, to recover which carbonising must be resorted to. This is a matter though that is very usually undertaken by the woollen men who buy the "burr waste" from the worsted topmaker, and it is, therefore, of no great importance to tho latfor. Should, the wools b.= literally filled with burrs, a more effective ! and thorough mechanical operation is cm- i ployed in which, when the rollers of the jsejja-!'

rating the mats of wool the fibres are seized by a roller fitted with fine sharp pans, and set at an angle so as to catch hold of and retain the fibres so long as ever strain is put upon them. Then burr beaters, similar to those before described, come in contact with the fibre, and, no slippage of the latter being possible,' the burr is driven off. The arrangement just described is a very brief description of an apparatus for which Woolcombcrs' Ltd., of Bradford, paid ,£20,000 for the rights to use. It is claimed that the wool goes forward through the machine (being stripped from the holding roller by means of a brush and deposited on Tollers clothed as ordinary carder cylinders) perfectly free from burr. Still another method depends for its efficacy on the crushing of .the burrs into small pieces, with the idea that in. the subsequent shaking processes these will be removed. To accomplish this, when the material has been effectively separated in fibre, and may be gathered up in film form from the earlier card cylinders, this film is nm over a plain-surfaced roller on which two sharply-fluted rollers revolve,' with the result that the vegetable matter being much thicker than wool, receives greater pressure, and is thereby divided into small particles. It may seem idle to talk about times when totally burr-less wool will come, seeing the burr plant is of such food-providing value to the pastoralist, and grows so extensively. At the same time if some means could be devised of eliminating this matter, so objectionable to all interested, a distinct advance in the march of progress would be made.