Self-acting Machines
Judd Eisenhauer
Industrial valves are vital components of plants and machines in that they perform necessary regulating and control tasks. When plants are planned and designed, their various elements are not considered in complete isolation from one another, but are instead selected to complement each other in their intended purpose. Therefore, the optimal valve selection is particularly important.
Self-acting control valves have special advantages with regards to the smooth interaction of all plant components. Industrial valves are vital components of plants and machines in that they perform necessary regulating and control tasks. When plants are planned and designed, their various elements are not considered in complete isolation from one another, but are instead selected to complement each other in their intended purpose. Therefore, the optimal valve selection is particularly important. Self-acting control valves have special advantages with regards to the smooth interaction of all plant components.
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The spinning mule is a machine used to spin cotton and other fibres. They were used extensively from the late 18th to the early 20th century in the mills of Lancashire and elsewhere. Mules were worked in pairs by a minder, with the help of two boys: the little piecer and the big or side piecer. The carriage carried up to 1,320 spindles and could be 150 feet (46 m) long, and would move forward and back a distance of 5 feet (1.5 m) four times a minute.[1]
It was invented between 1775 and 1779 by Samuel Crompton. The self-acting (automatic) mule was patented by Richard Roberts in 1825. At its peak, there were 50,000,000 mule spindles in Lancashire alone. Modern versions are still in production and are used to spin woollen yarns from noble fibres such as cashmere, ultra-fine merino and alpaca for the knitted textile market. [2][3]
The spinning mule spins textile fibres into yarn by an intermittent process.[4] In the draw stroke, the roving is pulled through rollers and twisted; on the return it is wrapped onto the spindle. Its rival, the throstle frame or ring frame, uses a continuous process, where the roving is drawn, twisted and wrapped in one action. The mule was the most common spinning machine from 1790 until about 1900 and was still used for fine yarns until the early 1980s. In 1890, a typical cotton mill would have over 60 mules, each with 1,320 spindles,[5] which would operate four times a minute for 56 hours a week.
There were two types of spinning wheel: the simple wheel, which uses an intermittent process, and the more refined Saxony wheel, which drives a differential spindle and flyer with a heck (an apparatus that guides the thread to the reels) in a continuous process. These two wheels became the starting point of technological development. Businessmen such as Richard Arkwright employed inventors to find solutions that would increase the amount of yarn spun, then took out the relevant patents.
The spinning jenny allowed a group of eight spindles to be operated together. It mirrored the simple wheel; the rovings were clamped, and a frame moved forward stretching and thinning the roving. A wheel was rapidly turned as the frame was pushed back, and the spindles rotated, twisting the rovings into yarn and collecting it on the spindles. The spinning jenny was effective and could be operated by hand, but it produced weaker thread that could be used only for the weft part of the cloth. (Because the side-to-side weft does not have to be stretched on a loom in the way that the warp is, it can generally be less strong.)
The throstle and the later water frame pulled the rovings through a set of attenuating rollers. Spinning at differing speeds, these pulled the thread continuously while other parts twisted it as it wound onto the heavy spindles. This produced thread suitable for warp, but the multiple rollers required much more energy input and demanded that the device be driven by a water wheel. The early water frame, however, had only a single spindle. Combining ideas from these two system inspired the spinning mule.
The hand-operated mule was a breakthrough in yarn production and the machines were copied by Samuel Slater, who founded the cotton industry in Rhode Island. Development over the next century and a half led to an automatic mule and to finer and stronger yarn. The ring frame, originating in New England in the 1820s, was little used in Lancashire until the 1890s. It required more energy and could not produce the finest counts.[6]
Samuel Crompton invented the spinning mule in 1779, so called because it is a hybrid of Arkwright's water frame and James Hargreaves's spinning jenny in the same way that a mule is the product of crossbreeding a female horse with a male donkey. The spinning mule has a fixed frame with a creel of cylindrical bobbins to hold the roving, connected through the headstock to a parallel carriage with the spindles. On the outward motion, the rovings are paid out through attenuating rollers and twisted. On the return, the roving is clamped and the spindles are reversed to take up the newly spun thread.
Crompton's machine was largely built of wood, using bands and pulleys for the driving motions. After his machine was public, he had little to do with its development. Henry Stones, a mechanic from Horwich, constructed a mule using toothed gearing and, importantly, metal rollers.[7] Baker of Bury worked on drums,[9] and Hargreaves used parallel scrolling to achieve smoother acceleration and deceleration.[10]
In 1790, William Kelly of Glasgow used a new method to assist the draw stroke.[10] First animals, and then water, was used as the prime mover. Wright of Manchester moved the headstock to the centre of the machine, allowing twice as many spindles; a squaring band was added to ensure the spindles came out in a straight line.[11] He was in conversation with John Kennedy about the possibility of a self-acting mule. Kennedy, a partner in McConnell & Kennedy machine makers in Ancoats, was concerned with building ever larger mules. McConnell & Kennedy ventured into spinning when they were left with two unpaid-for mules;[12] their firm prospered and eventually merged into the Fine Spinners & Doublers Association. In 1793, John Kennedy addressed the problem of fine counts. With these counts, the spindles on the return traverse needed to rotate faster than on the outward traverse. He attached gears and a clutch to implement this motion.[13]
William Eaton, in 1818, improved the winding of the thread by using two faller wires and performing a backing off at the end of the outward traverse.[14] All these mules had been worked by the strength of the operatives. The next improvement was a fully automatic mule.
Richard Roberts took out his first patent in 1825 and a second in 1830. The task he had set himself was to design a self-actor, a self-acting or automatic spinning mule. Roberts is also known for the Roberts Loom, which was widely adopted because of its reliability. The mule in 1820 still needed manual assistance to spin a consistent thread; a self-acting mule would need:
A counter faller under the thread was made to rise to take in the slack caused by backing off. This could be used with the top faller wire to guide the yarn to the correct place on the cop. These were controlled by levers and cams and an inclined plane called the shaper. The spindle speed was controlled by a drum and weighted ropes, as the headstock moved the ropes twisted the drum, which using a tooth wheel turned the spindles. None of this would have been possible using the technology of Crompton's time, fifty years earlier.[15]
Oldham counts refers to the medium thickness cotton that was used for general purpose cloth. Roberts did not profit from his self-acting spinning mule, but on the expiry of the patent other firms took forward the development, and the mule was adapted for the counts it spun. Initially Roberts' self-actor was used for coarse counts (Oldham Counts), but the mule-jenny continued to be used for the very finest counts (Bolton counts) until the 1890s and beyond.[16]
Bolton specialised in fine count cotton, and its mules ran more slowly to put in the extra twist. The mule jenny allowed for this gentler action but in the 20th century additional mechanisms were added to make the motion more gentle, leading to mules that used two or even three driving speeds. Fine counts needed a softer action on the winding, and relied on manual adjustment to wind the chase or top of the perfect cop.[17]
Spinning wool is a different process as the variable lengths of the individual fibres means that they are unsuitable for attenuation by roller drafting. For this reason, woolen fibres are carded using condenser cards which rub the carded fibres together rather than drafting them. They are then spun on mule-type machines which have no roller drafting, but create the draft by the spindles receding from the delivery rollers whilst that latter, having paid out a short length of roving, are held stationary. Such mules are often complex involving multiple spindles speeds, receding motions, etc. to ensure optimum treatment of the yarn. [18]
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