Carding and Combing Machinery.— The first machine to which the cotton goes in a fac tory is the bale-breaker, on which the cotton is opened and beaten. In modern practice there is less beating of cotton apd more dependence on air suction to remove the dirt. Automatic feeders are now used with breakers. The breaker-lapper, after cleaning the cotton stock, converts it into a lap or roll, after which it may go to a finishing dapper. The carding machine was invented by Lewis Paul and im proved by Arkwright. Modern machines are usually of the revolving flat card type. The main cylinder of about 50 inches diameter bears card-clothing or a surface of points resembling a very fine wire brush. This clothing may have from 40,000 to 90,000 points per square foot. Above and opposed to this cylinder is an end less apron called a top flat, which also bears card-clothing. The cylinder and flats moving oppositely comb out or card, or render parallel, the fibres of cotton that come into the machine in the form of a lap, and the top flat removes all knots and snarls. This lap is taken up by the licker-in, a toothed cylinder that feeds or supplies the carding machine. After passing the cards the cotton is received by the doffer or doffing cylinder.
A recent French invention is the Roth aspirator, which is applied to combers as a sub stitute for the doffer or doffing combs. It is a perforated tube with a suction draft and does the work without any harsh handling of the cotton fibres. The Whitin and high-speed comber has 8 heads, takes laps 12 inches wide and has devices for reducing vibration. It runs normally at 135 nips per minute.
The cotton comes from the doffer as a fleecy strand termed a sliver. It is deposited in cans and may go to a sliver-lap machine and be formed into a lap about 15 inches in diame ter and 10 or 12 inches wide. This lap may go to the ribbon lap machine, which doubles four laps into one, the object being to obtain greater evenness from the repeated doublings and drawings out, and paralleling of the fibres. The laps from the ribbon lap machine are placed on the comber, which douoles eight to one. A combed sliver yarn gets 640 extra doublings and is smoother and more lustrous as a result.
Drawing, Roving and Twisting.— The drawing frame receives the sliver, and by pass. ing it between series of rolls at increasing speeds draws it out finer. These machines have been highly developed and are truly automatic. When the drawn slivers are slightly twisted they are termed roves or rovings. Roving machinery includes slubbers, intermediates, fine roving frames and jack-frames. The product of the roving machine is usually delivered on bobbins and may then be termed yarn.
The Spinning Frame.— This is the machine that made Richard Arkwright famous, it being a development of the spinning jenny invented by James Hargreaves. Many other machines in the cotton industry are based on the same operating principles as the modern spin ning frame. It draws out the fibres and twists the cotton yarn hard and firm and winds it on bobbins. The modern frame first passes the roving through a series of rolls that permit a variation in twist. When drawn to the required density and twist the yarn passes to the bobbins, mounted on rows of spindles that stand upright and rotate on either side of the frame. Frames run from about 112
to 352 spindles each, the 240-spindle frame being now popular. After being spun, the yarn is doubled and twisted to form thread. It may be twisted wet or dry; in wet twisting the yarn is drawn from a creel through a trough of water. In modern twist frames a wide range of twist combinations is possible for making all kinds of thread. With a builder-motion the bobbins may be wound straight, taper-top or for warp or filling. While in the yarn it is often desir able to bleach, dye or mercerize the cotton.
The mule-spinner or spinning-mule, invented by Samuel Crompton, is in less use than form erly. It is a combination of the drawing-rollers and jenny used in the early history of modern machine weaving. It has a carriage that travels away from the drawing rollers as the threads are twisted and comes back as the thread is wound on the bobbins. While the mule draws, stretches and twists at one operation, it is not as satisfactory as the later and more highly developed frames. The ring-spinner or nng f rame is a spinning machine in which a metal loop revolves around each spindle to carry the thread. Spoolers and quillers are machines for winding the yarn on either spools or quills the 'modern quill being simply a paper tube.
See SPINNING.
Weaving Looms.—These are made in al most infinite variety for various purposes. The heavy-pattern loom, the wide loom and the end cam loom are perhaps the most common. For fancy weaving the dobby loom is generally em ployed. There are also special gingham looms and looms for light and heavy duck weaving, and two-, four- and six-box fancy looms. See TEXTILES; WEAVING.
Testing Machinery.—A typical form of yarn-examining machine consists of a light hand-reel, in which a black card may be fitted to carry the wound yarn or thread. A moving guide spaces the yarn so that every strand is well separated. When wound the card of yarn may be placed under a microscope, or in the reffectorscope, which is a small box with a dark background, a mirror and an easily posi tioned microscope. To test yarn for dampness the conditioning oven is employed.. A sample of yarn is hung on the scale of the oven and heated. As the moisture is dried out the re duced weight is registered on the scale. For strength-testing, an upright frame is provided with grips in which a number of leas of thread or yarn may be broken at one operation. If four leas are strained by the reel at one time, and the dial shows they break at 88 pounds, it follows that their average strength is 22 pounds. A single-thread recording tester is also manu factured. The operator can run through a sample, breaking it a dozen times, and follow this with other samples, and withdraw a card on which are recorded the breaking strains of each break of each sample. The average strength as well as the greatest weakness of a lot of thread is thus readily obtained. There are several forms of twist-testing machines and some record the contraction resulting from the twisting.
Bibliography.— Barker, A. F., 'Textiles) (New York 1913); Miller, Cotton System) (Austin, Tex. 1909); Peake, (Cotton from the Raw Material to the Finished Product) (New York 1911); and trade papers in the textile industry.