THE COLLIERY GUARDIAN AND JOURNAL OF THE COAL AND IRON TRADES Vol. CXIII FRIDAY, MAY 11,-1917. No. 2941. Recent Developments of the Whiting Hoist in Deep Winding.* By B. GRAY and J. WHITEHOUSE. same space as was previously occupied by the four, thus giving a greater area on the wearing tread, which had been introduced under the rings, with special arrangements for lubricating, and the pressure per square inch was proportionately reduced. The conditions under which these hoists worked were as follow: Depth of wind, 4,100 ft.; diameter of wind- ing rope, If in.; weight of rope per foot, 4*25 lb.'; diameter of tail rope 1T9K in.; weight per foot, 3-75 lb. ; weight of skip, 9,0001b.; weight of half tail pulley and frame, 1,100 lb.; weight of rock, 10,0001b. When the hoists were started up, three turns of rope were used round the reels, and the hoists ran under . ____j----- --- ----------v - these conditions for some months. From the com- On completion of the sinking operations, the hoists mencement complications presented themselves, neces- sitating careful daily examinations, and these were undoubtedly due to the load on each end of the rope being multiplied by the number of turns roun^l the reels, which tended to pull the,two shafts together. The principal difficulties experienced were: — (1) Heating of bearings. 1 (2) Irregularity in the air gap of the motor, which had to be adjusted daily. (3) The general tune of the winder when running was one of over-stressing. (4) The enormous pressure on bearings, due to the rope pull, which expelled the lubricant in the bearings when stationary, was shown by the excessively high starting current required to move the hoist after it had been standing for a short time. This was as much as 1,100 amperes on a 2,100 volt circuit. . One particularly noticeable feature with the hoist working under the above conditions was the entire absence of slip between the rope and the engine under any circumstances, even when loads were as high as - 6J tons, and .when forcing the acceleration period, or when, owing to failure of current, the brakes were suddenly applied when running at maximum speed. The continual over-stressing due to the rope pull resulted finally in the complete fracturing of the back reel shaft. The failure of this shaft was possibly accelerated by the fact that all braking was done through'it, both the eddy current and the mechanical brakes operating here. The diameter of the broken shaft was 20 in. After considering the past experience and the final stoppage of one of the hoists owing to the fracturing of one of the large shafts, it was considered, unsafe to continue working the hoists under the old conditions, and to merely replace the broken shaft, without at the same time relieving the engine of the abnormal stresses under which it had been working. It was therefore decided to reduce these stresses by taking off one further turn of rope from the reels, this now leaving only two turns roupd the engine. This change at once showed a; great improvement in the • working conditions, and completely changed the running of the engine, by removing all si’gns of stress- ing, both as regards the sound whilst winding, and the trouble of bearings over-heated. Further, the difficulty experienced formerly in maintaining an even , air gap on the motor was to a great extent eliminated, and the starting current was considerably reduced, never exceeding 900 amperes. After the change, it was noticed that slip between rope and engine was still absent under any conditions. - It was felt, however, that this improvement was not sufficient to ensure the continuous running of the engine, and that it would only be' a question of time before another shaft would ^be fatigued and would fracture, with possibly very serious consequences. Following upon the encouraging results obtained, when. running with two turns, it was decided to attempt running with one turn of rope round the engine reels, and by so doing possibly obtain perfect' conditions for winding by the Whiting system. Upon . carrying out this alteration, it was found that the engine worked like an entirely different machine, the improvement as far as tM running of the engine was concerned being very marked. * v Slip, however, between rope and reels now took place for the first time, the amount varying from nothing up to 1,000 ft. per trip, but from the fact that some trips were entirely free from slip, it was thought that it would be possible to ■ overcome this disadvantage, and retain the single turn of rope. When the single turn system was first adopted, one ring in each set of the Walker rings was used for the driving groove, and winding was continued for some months in this way. It could not, however, be looked Some interesting experiments and developments have been carried out at No. 3 shaft, Village Deep, in winding with Whiting hoists. Before proceeding with these, a short description of the original plant and the various steps which led up to the conditions which now obtain will be given, together with some observations as to the possibilities of this improved system being applied to deep winding in the future. The original plant consisted of two standard 17 in. anfl 28 in. by 60 in. twin tandem, compound Whiting engines. The Whitin'g reels in these engines were replaced-by 8 ft.;diameter drums for sinking purposes, and with them the seven-compartment shaft was sunk to a depth of 4,100 ft. vertically. were converted to the Whiting system, being fitted with 12 ft. diameter reels. The steam cylinders were discarded, and the engines were each driven electric- ally by a 1,400 horse-power motor mounted close to the reel on the front shaft. Similarly, an eddy current brake, capable of exerting; a braking effect of 1,200 horse-power, was placed close to the reel on the back shaft, and the usual coupling rods between the two shafts were retained. Tail ropes hang in the shaft ’ and pass round a pulley at the bottom. This pulley is mounted on a frame, which runs in guides, so that it It will be obvious that such uncertain conditions of running had of necessity to be altered, since the driv- ing of the hoists proved exceedingly difficult, and was a great strain on the drivers. In the first place, it was necessary to give the driver accurate knowledge as to the position of the skips in certain parts of the shaft, and this was accomplished by installing an abso- lutely positive warning bell to be operated by the skip itself at a known point in the shaft. The arrange- ment is shown in fig. 2, and is as follows:—At the desired depth in the shaft a station was cut along the whole of one side, the dimensions being about 3 ft. deep by 7 ft. high. In the centre of each compart- ment of this station a light triangle is suspended, carrying at its lower end a motor cycle wheel fitted with a pneumatic tyre. This is so hung that it comes into contact with a curved rubbing plate, which has been fitted to the skips for this purpose. In coming in contact with the skip as it passes this point in the B * C A. B. C. of Shaft Hoist. D. 18tK ley el. E. Bell boxes. F. Spill X cut. Fig. 1.—Vertical Section Fitted with Whiting Loading chute. Spill plate. Floating wood cone. % Fig. 2.—Diagram of Warning Bell Gear. A. Watertight chamber .0- Rubber buffer. accessible down ladder. D. Contacts.. B. Spring. E. Cycle wheel. E C is able to rise and thus prevent the pulley from being 1 smashed in case of an overwind. The arrangement is shown in fig. 1. Similar hoists to those under consideration, but „ - _____ , ______________________ steam driven, have been working some months at the upon as satisfactory, owing to intermittent slipping. City Deep, where weaknesses had developed in the XT 1’ ’ ’ ’ cast iron reels, and, as a result of this experience, cast steel reels of special1 design were installed at the Village Deep. Further, the Walker rings were made to a much heavier design to overcome the.effect of stretching due to the rolling action, and the number of rings was reduced from four to three, the latter occupying the * Journal of the South African Institution of Engineers. Very slight variations in running conditions were suffi- cient to, induce excessive slip or to entirely eliminate it. For instance,, with a badly lubricated rope, slip invariably occurred, whereas when the rope had been recently greased slip would be entirely absent. Again, during a misty rain, slip often took place, whilst a heavy rain had no effect; and, further, with a new rope no slipping would occur for about a month, but as the crowns,of the wires became worn, slipping would again appear. ' shaft, this wheel carries the triangle/ back, and so closes the circuit of an electric bell, which rings on to the drivers’ platform. The drivers are thus able to check the exact position of the skips with their indi- cator, and to tell to what extent, if any, slip has occurred, the device acting on both the up and down trips. It is extremely light and durable, and the tyres have lasted well, the original ones still being in use after nearly three years’ service. An important point in the installation is the fact that it can be inspected at any time without in any way interfering with the winding operations, and, what is more important, / without danger to workmen. Having; installed -this-i .device,- the authors were' in.* a position .to carry; on experiments with greater confir dence. -■> . •; In attempting to eliminate slip, the Walker rings On the. back reel were replaced by a locally-made solid cast iron ring, which was built fast on to the: reel itself. On the front* reel the Walker rings were retained. . This had the effect of lessening the slip, showing that: the experiment was in ,the right direc- tion. Later, however, it was found that uneven wear was taking place in the two reels, due to the difference in the materials of which the treads were made, one being steel and the other cast iron? The latter wore much ..quicker than the steel, and the difference in the diameters was very quickly noticed by the drivers, owing to the peculiar sound of the engine, and an increased tendency on the part of the rope to slip. In' order to correct this, a simple tool holder device was attached to the engine frame between the reels, and the grooves were periodically turned up, the turning motion being supplied by the engine itself. It must be 'pointed out that with cthe last conditions slipping only took place when the engine was moving in one direction and . not in the other, the slip taking place when the engine skip, as distinct from the one on the end of the rope which passes rotmd the deflect- ing pulley, was being raised from the bottom of the shaft. The explanation of this was soon found. By refer- ring to fig. 3, it will be noticed that the engine, whenx raising the engine skip, tends to push the rope out to.