Textiles, for Commercial, Industrial, and Domestic Arts Schools. William H. Dooley
is removed, leaving only the colorless animal oil in the fiber. If the work is not thoroughly done the wool passes as “unmerchantable washed.” “Tub washed” is the term applied to fleeces which are broken up and washed more or less by hand. Scoured wool is tub washed with warm water and soap, and then thoroughly rinsed in cold water until nothing remains but the clean fiber.
An improved method of washing wool by hand is to have a series of tanks with pressing rollers attached to each tank: the wool is agitated by means of forks, and then passed to the pressing rollers and into each tank in succession. The tanks are usually five in number, and so arranged that the liquor can be run from the upper to the lower tank. Upon leaving the pressing rollers the excess of water is driven off in a hydro extractor[11] and the wool is beaten into a light, fluffy condition by means of a wooden fan or beater.
Wool Drying. The process of drying wool is not intended to be carried to such an extent that the wool will be in an absolutely dry state, for in such a condition it would be lusterless, brittle, and discolored. It is the nature of wool to retain a certain amount of moisture since it is hygroscopic, and to remove it entirely would result in partial disintegration of the fibers. Buyers and sellers have a recognized standard of moisture, 16 per cent. If, on the other hand, it is left too wet, the fibers will not stand the pulling strain in the succeeding operations, and if not broken, they are so unduly stretched that they have lost their elasticity.
The theory which underlies the drying process is that dry air is capable of absorbing moisture, hence by circulating currents of dry air in and around wet wool, the absorbing power of the air draws off the moisture. For continuous drying free circulation is a necessity, as otherwise the air would soon become saturated and incapable of taking up more moisture. Warming the air increases its capacity to absorb moisture; thus a higher temperature is capable of drying the wool much quicker than the same volume of air would at a low temperature. A free circulation of air at 75 to 100 degrees F., evenly distributed, and with ample provision for the escape of the saturated air, is essential for good work.
Oiling. After being scoured wool generally has to be oiled before it is ready for the processes of spinning, blending, etc. As delivered from the drying apparatus, the wool is bright and clean, but somewhat harsh and wiry to the touch, owing to the removal of the yolk which is its natural lubricant. To render it soft and elastic, and to improve its spinning qualities, the fiber is sprinkled with lard oil or olive oil. As the oil is a costly item, it is of consequence that it be equally distributed and used economically. To attain this end various forms of oiling apparatus have been invented, which sprinkle the oil in a fine spray over the wool, which is carried under the sprinkler by an endless cloth.
Burring and Carbonizing. After wool has been washed and scoured it frequently happens that it cannot be advanced to the succeeding operations of manufacture because it is mixed with burs, seeds, leaves, slivers, etc., which are picked up by the sheep in the pasture. These vegetable impurities injure the spinning qualities of the stock, for if a bur or other foreign substance becomes fastened in the strand of yarn while it is being spun, it either causes the thread to break or renders it bunchy and uneven. For removing burs, etc., from the wool two methods are pursued: the one purely mechanical, the other chemical, and known respectively as burring and carbonizing.
Bur Picker. For the mechanical removing of burs a machine called the bur picker is employed. In this machine the wool is first spread out into a thin lap or sheet; then light wooden blades, rotating rapidly, beat upon every part of the sheet and break the burs into pieces. The pieces fall down into the dust box or upon a grating beneath the machine, and are ejected together with a good deal of the wool adhering to them. Often the machine fails to beat out fine pieces and these are scattered through the stock.
Process of Carbonizing. For the complete removal of all foreign vegetable substances from wool the most effective process is carbonizing, in which the burs, etc., are burned out by means of acid and a high degree of heat. The method of procedure is as follows: The wool to be treated is immersed in a solution of sulphuric or hydrochloric acid for about twelve hours, the acid bath being placed in cement cisterns or in large lead-lined tubs and not made strong enough to injure the fiber of the wool. During the immersion the stock is frequently stirred. Next, the wool is dried and then placed in an enclosed chamber and subjected to a high temperature (75 degrees C.). The result of this process is that all the vegetable matter contained in the wool is “carbonized” or burned to a crisp, and on being slightly beaten or shaken readily turns to dust. This dust is removed from the wool by various simple processes. The carbonizing process was first introduced in 1875, though it made but slight headway against the old burring method until after 1880.
Blending. Pure wool of but one quality is not often used in the production of woven fabrics, so, before the raw material is ready for spinning into yarn, or for other processes by which it is worked into useful forms, it is blended. Wools are blended for many reasons (among which cheapness figures prominently), the added materials consisting usually of shoddy, mungo, or extract fibers. Ordinarily, however, blending has for its object the securing of a desired quality or weight of cloth. The question of color, as well as quality, also determines blending operations, natural colored wools being frequently intermixed to obtain particular shades for dress goods, tweeds, knitting yarns, etc. Stock dyed wools are also blended for the production of mixed colors, as browns, grays, Oxfords, etc. There is practically no limit to the variety of shades and tints obtainable by mixing two or more colors of wool together. The various quantities of wool to be blended are spread out in due proportion in the form of thin layers, one on top of the other, and then passed through a machine called the teaser. The teaser consists of a combination of large and small rollers, thickly studded with small pins, which open the wool, pull it apart, and thoroughly intermix it. A blast of air constantly plays upon the wool in the teaser and aids the spikes and pins in opening out the fibers. The material is subjected to this operation several times and is finally delivered in a soft, fleecy condition, ready to be spun into yarn.
FOOTNOTES:
[10] Skins.
[11] A wire cage enclosed in a metallic shell which revolves at a high speed causing sixty or seventy per cent of the moisture to be removed.
CHAPTER III
WOOL SUBSTITUTES AND WASTE PRODUCTS
Remanufactured wool substitutes are extensively used in the manufacture of woolen and worsted goods. There is no need for the prejudice that is sometimes met regarding these reclaimed materials, for by their use millions of people are warmly and cheaply clothed. If the immense quantity of these materials were wasted, countless persons would be unable to afford proper clothing, as it is difficult to estimate what the price of wool would be; and it is also doubtful if a sufficient quantity could be produced to supply the need. In almost all instances the use of wool substitutes is for the special purpose of producing cloths at a much lower price.
The cloths made from waste products, such as noils, are not much inferior in quality to those produced from the wool from which the noils are obtained; but the great majority of cloths made from other waste products are much inferior. The following are