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May, 1943

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An adaptation of the usual type of horse whim gin was utilised at the Walker Colliery about 1750. In this case, instead of the drum being moved by direct leverage, it was rotated by gearing, eight horses driven at a rapid trot being necessary. This arrangement enabled 5½-6½ cwt.. of coal to be wound at the rate of 300 ft. per minute. The geared whim gin was not a complete success and after a few years' use was discontinued.

Coal was wound by a fire engine in 1763 at Hartley Colliery. This appears to be the first effort to raise coal by steam power, and it is suggested that the engine used was of the Newcomen type, which employed the atmospheric principle. This, and other installations, Were a failure owing to the difficulty in obtaining a rotary motion from the fire engine. This difficulty was not overcome until Watt introduced the crank in 1780. It was not, however, until 1784 that Watt installed at Walker Colliery the first steam engine capable of producing a rotary action. The invention of the crank and other improvements to the steam engine ensured the successful application of steam for winding purposes, and from this time the introduction of steam winding engines was considerably accelerated.

In the previous article a description was given of the water wheel used for winding purposes. This was frequently used where a natural head of water was available but with the introduction of fire engines, it became possible to pump water up any mine shaft and to utilise it for rotating the water wheel which in turn caused the winding drum to revolve. This system was extensively used from 1760-1800, especially in the northern part of England.

By the early part of the nineteenth century practically all previous types of winding had been made obsolete by the success achieved by the steam engine, although a mechanical system of winding in shallow shafts, by an endless chain arrangement, was popular from 1790-1840.

During the early part of the nineteenth century and up to about 1850 the steam engine employed was the single-cylinder vertical type, with grab hand reversing gear and balance chains in a staple pit. A typical winding engine of this period is shown in Fig. 1, which illustrates a beam engine turning two horizontal winding drums, each 4 ft. in diameter, by means of bevel gearing. The arrangement was so designed to enable the engine to wind simultaneously from two shafts in close proximity, guide pulleys and frames supporting and directing the winding chains to the shafts. The mouth of each shaft was protected by wooden doors which were pushed open by the ascending bucket and which closed by their own weight when the bucket had passed. The buckets were usually of wrought iron having a capacity of 6-7 cwt.

Fig. 2 illustrates a typical layout adopted in the northern coalfield during the middle of the nineteenth century. The winding system consisted of a vertical single-cylinder, high-pressure, direct-acting engine connected directly above to a crankshaft on which were the fly wheel and two drums — one drum accommodating the flat rope used for winding and the other, which was conical and smaller in size, served to raise the small coal to the screens by means of a chain. The piston rod was guided by the Watt's parallel motion and the cylinder was supported on a cast iron column at a considerable height above the ground. Attached to the fly wheel was a strap brake applied by the engineman's foot. The exhaust pipe was carried through the cistern from which the feed pump obtained the supply for the boiler.

The pit top consisted of a timber platform carried on columns 16 ft. above the ground in order to facilitate screening and loading. The "keps" were vertical wrought iron bars, which were fixed to horizontal bars. The platform was covered with cast iron plates or "flatsheets" to make a smooth surface for easy manipulation of the tubs. Usually the cages were double decked, consisting of three wooden platforms kept apart by wrought iron straps and struts. Tub catches were attached to the roof of each deck to secure the tubs in the cage.

Fig. 3 illustrates a typical vertical winding engine of the first half of the nineteenth century — an early example of this type was erected by Thornewill & Warham, Burton-on-Trent, at the Church Gresley Colliery in 1844, and can be considered as the typical winding engine of the period. It had a 36 in. diameter cylinder x 5 ft. stroke, fitted with improved valve expansion gear, steam brake and reversing gear, and the various parts were made adjustable so as to take up wear. The drums could take either flat or round ropes. It is a tribute to the design and sound engineering practice of the makers that this particular engine was not dismantled until 1941, almost 100 years after its installation. The last of this type to be installed by Thornewill & Warham* was in 1853, when a vertical steam winder was erected at Shipley Collieries, having a 33 in. diameter cylinder x 5 ft. stroke.

The increased adoption of the steam engine for winding, combined with the necessity for deeper shafts, accelerated the rate of improvement in the valve gear of winders during the latter part of the nineteenth century. Earlier forms of valve gear consisted of the slide-valves of the side-by-side type with a particularly large clearance, for horizontal engines and, later, double-beat Cornish valves for both horizontal and vertical engines. The. Cornish valve was eventually fitted with cut-off gear, activated by a governor, or more often by the throttle valve. Corliss valves were eventually installed with separate inlet and exhaust in order to overcome the necessity for the large clearances required and the loss of steam through valve passages with the former types. These were, in turn, replaced by double-beat inlet drop valves and Corliss exhaust valves for high pressure steam engines.

The last vertical single-cylinder engine to be erected was at Wearmouth in 1868. which had a capacity of 4 tons per wind 1½ of a depth of 570 yards in approximately 1½ minutes. This type of winder was superseded by the horizontal engine which was very much in vogue during the period 1870-1890. This was of the double-acting type with slide valves controlled by link motion. There were two cylinders each designed to lift the whole load, which enabled the engine to start from any crank position; the cranks were set at 900 to each other on a common crankshaft and were of the overhanging type. The cylindro-conical drum was keyed centrally on the crankshaft and carried two steel winding ropes, one being wound in whilst the other was paid out. Load on the engine was balanced by arranging for a portion of each side of the drum to be of conical shape.

A hand brake operated on a brake path in the centre of the drum face, and was controlled by a subsidiary steam cylinder, with a slide valve, operated by means of a hand lever. The engine throttle was of the disc type, directly controlled by a hand lever. Brake reversing gear and throttle controls were all brought to a point from which they could be operated by one engineman.

It can be well appreciated that with greater depths, increased outputs required and the rapid development of mechanical science, the power and speed of winding engines would be in a direct ratio with the duties they had to perform. Earlier than 1840, the maximum horse power developed never exceeded 50, but after 1840, 150 h.p. winding engines became common. An example of the latter type was at Monkwearmouth. In Scotland high-pressure steam engines were introduced during the same period; by 1885 steam pressures of 100 lb. per sq. in. had been reached, while in 1888, cross-compound horizontal winding engines were tried, finally evolving in 1902 into four-cylinder winding engines with two high-pressure and two low-pressure cylinders.

The early part of the twentieth century saw great strides in the development of large power stations and the greater use of electric power. Its provision enabled electric winding systems to be more extensively introduced into English mines. It is not the purpose of this article to deal with the advantages of the electric winder, especially of its ability to wind large loads from extreme depths at great speed with easy control, efficiency and safety. For the purpose of this article, however, it may be said that electric winding equipment has been developed on the following lines :—

(1) D.C. motors coupled direct to the drum with Ward-Leonard shunt control, the current being obtained from a d.c. generator driven by an a.c. motor.

(2) A similar system as in (1) but with a heavy flywheel arranged between the a.c motor and the d.c. generator.

(3) A.C. motor geared or directly coupled to the drum.

(4) A similar arrangement to (3) but with a flywheel equalising set in parallel to take up some of the peak load on starting.

The foregoing paragraphs have briefly indicated the development of winding engines; increase in the safety and speed of winding has been dependent upon many other factors such as guides, ropes and safety appliances, which will be dealt with at a later stage. To deal with large loads from great depths of necessity introduces many complications and difficulties and the following briefly outlines several methods of overcoming them.

It was early realised that, because of their own weight, round winding ropes could only be used to a certain winding depth and that theoretically, tapered ropes should overcome this difficulty. To dispense with the use of ropes entirely, Blanchet introduced into France a hoisting arrangement on the principle of the pneumatic tube. Although the system was used on a small scale it did not prove superior to a system using wire ropes. Fig. 4 indicates the arrangement of this winding system; (a) shows the cage at the bottom of the shaft and (b) at bank. A tube 5 ft. 3 in. in diameter and constructed of plate 5/16 in. thick was placed in the shaft. The tube consisted of 20 ft. lengths riveted together with butt joints and countersunk rivets. The piston was constructed in two parts, one at the top of the cage and the other at the bottom; the former was made in two portions and placed at such a distance apart, that in passing the doors through which the tubs are changed one part was always in an uncut portion of the tube; this enabled the piston to pass the doors without loss of pressure. The lower part of the piston, below the cage, carried a parachute, p. The cage held 9 tubs one above the other, the coal load being nearly 5 tons; the total weight of the piston, cage; tubs and coal was about 12 tons.

When the air was exhausted above the piston, the latter started to ascend, whilst for descent, exhaustion was stopped, the connection with the exhaust engine being severed by means of doors at C, and air allowed to pass to the top of the piston through the regulator, c. To remove the tubs from the cage, three double doors, f, were provided in the tube, both at the top and bottom, these corresponding to three levels in the headgear. Three movements of the cage took place to change the 9 tubs, and to keep it steady three double sets of stops, S1, S2, S3, were introduced which could be thrust into the tube, or withdrawn by means of a single lever. When the cage was situated between stops, S3, of the two sets, decks 1, 4 and 7 were handled, while if the cage were confined by stops, S1 of each set, tubs 3, 6 and 9 were capable of being discharged.

Situated at the bottom of the shaft was the equilibrium pipe E, passing from the bottom of the tube to a point sufficiently high to be above the piston during the period when the tubs were being changed. When cock g was closed, the pressure of air in the bottom kept the piston up against the top stops, and when the cock was opened, and the main inlet and outlet valves, h and e, shut, the air below was rarefied, and the cage fell on to the bottom stops. At the pit top the two pipes A and B were provided with the stop cocks c and i; stopcock c was in connection with the atmosphere to allow the cage to descend while i was in connection with the exhausting engines and was used to move the cage if required whilst banking was in progress. When the cage ascended, the doors J, f and e were shut, but upon arising at the top it was stopped firstly by automatically shutting at k the connection with the exhausting engine at C and secondly by moving, the valve l, which admitted air from the atmosphere; if the ascent continued, the valve n was lifted and the tube opened to atmosphere. To prevent shock when opening these valves the top part of the piston carried a spring buffer, a. When descending the cage automatically closed the escape valve at n.

This hoisting apparatus also assisted in ventilating the mine, as during the descent of the piston, the valve h was shut and e opened, and all the air contained in the tube was forced to the surface; during the ascent the valve e was shut and h opened, so that an amount of air equivalent to the volume of the tube was exhausted from the mine and discharged to atmosphere when the piston descended.

Koepe system of winding

For deep winding, long lengths of rope are required which necessitate the use of heavy and large winding drums; angling of the rope is also increased. To remove the necessity of using large drums, to reduce power, to obviate angling and wear and tear on the rope, Koepe introduced his winding system at Hannover Colliery, Westphalia, in 1877. His system is shown in Fig. 5 and may be said, briefly, to substitute a single grooved pulley for the ordinary winding drum. The winding rope passed from one cage over its headgear pulley round the "drum pulley," and after passing over the other headgear pulley was connected to the second cage. The winding rope encircled about 190°-200° of the periphery of the "pulley." There was a balance rope beneath the cages, so that the arrangement, to all intents and purposes, was an endless rope, the cages being attached at two convenient points. The "drum pulley" consisted of two outside cases of an ordinary cylindrical drum, bolted together, and securing between them a band of hard wood on which a groove was made to receive the winding rope, the depth of this groove being generally equal to twice the diameter of the rope. Instead of being placed parallel the headgear pulleys were angled towards each other with the object of reducing side friction. It was found that the coefficient of adhesion between steel ropes and the wooden groove was 30 per cent. The first application of this system of winding in England was at Bestwood Colliery in 1890, but it was soon abandoned owing to the slip which took place when the winding ropes were oiled. The second installation was at Sneyd Colliery, and this had a much better life.

Various improvements have been made in the Koepe system, such as the use of flat ropes, the introduction of four headgear pulleys with two ropes and a drum with two grooves, tensioning devices, but generally speaking it is not a system which has appealed to English mining engineers.

Very similar in design to the Koepe was the Whiting system, illustrated diagrammatically in Fig. 6, but in which, in order to permit increased grip two grooved pulleys, both driven, were used, the rope passing several times round each.

* Now Thornewill & Warham Successors: (Proprietors S. Briggs & Co. Ltd.)

(To be continued)

Drawings and Photographs accompanying the article