1180 THE COLLIERY GUARDIAN. May 29, 1914. ________________________________________________ It would appear as if this angle A Ba may be greater than ABC for overlapping, as the rope does not leave the groove, as it has to do in the case of overlapping, as previously mentioned, E, fig. 9. The angle AB C in fig. 11 for overlapping, where the rope has to rise in each overlapping coil on to the crown of an underlapping coil, and drop into the space between two of the under-coils, depends on :— (1) The diameter of the rope; (2) The diameter of the drum; (3) The flexibility of the rope; and possibly on other factors not immediately apparent. Immediately the rope gets into position E, fig. 9, it is drawn into the line C B, fig. 11, and unless it catches B — ’.in 3.9/? V CN- Fig. 15. .-’204 J a A :■......II -0" YmniSr' Mt*- ..‘if.. a. A - C Fig. 16. o tn l-.io co ' 35’. I diameter, one to 120. Works satisfactorily in the grooves at'an angle of one in 35, and recoils satisfactorily at an angle of one in 69. Four ropes only have to date completed their work under these conditions, and have averaged 27 months 28 days’ life, 297,793 tons of coal, and cost -0822d. per ton of coal. Summary of Examples. Example No. Diam. of Drum Diam. of Rope Grooved Barrel angle ABa Overlapping angle ABC Depth of groove Coiled satisfac- torily Failed to coil Proportion rope to drawn diam. Coiled satisfac- torily Failed to coil ft. in. in. in. 1 6 0 1 — —- — 1 to 72 1 in 33 — 2 5 6 1 — — — 1 to 66 1 in 28 — 3 13 0 1 .— — — 1 to 156 1 in 94 1 in 42 4 24 0 1-H 1 1 in 82 — — — — 5 15 0 1 in 35 — 1 to 120 1 in 69 — Designed. Not yet in use. A 12 0 2 § 1 in 41 1 to ’72 1 in 50 B 18 0 2J- 1 in 48 1 to 96 1 in 60 The writer trusts other members will give instances similar to the above, so that definite data may be gathered on the subject. In overlapping it will be noticed that the point E, fig. 9, occurs at the same place in the circumference on each coil right across the face of the drum. The wear on the rope so caused will therefore arise at fixed intervals (the drum circumference in length) through- out the rope. The position of this series of points can only be changed by paying out a length of rope, less than one coil, from the dead coil end. By paying out STORAGE OF COAL. The Carlsruhe Gas Research Station, says the Gas World, has issued a report on certain coal which had been set aside for an investigation of the question what difference it makes whether coal is stored in the open air or under cover. In February 1910 the Diisseldorf gas works stored 150 tons of Konigsgrube coal in the open air to a depth of 11 ft. 8 in., and another 150 tons in a shed to a depth of 10 ft. In July and August 1913, that is, after three-and-a-half years’ storage, 10 tons of each were sent to Carlsruhe, and the two coals were carbonised under exactly similar experimental conditions. The most important of the data obtained are the following :— Coal stored Coal stored in Composition of the coal:— Ash.......................... Moisture, gross ............... Carbon ...................... Carbonisation data:— Temperature of carbonisation, degs. Cent.................. Yield of gas (at 15 degs. Cent. and 760 mm.) ............... Yield of coke., per cent......... „ tar „ ......... ,, liquor „ ........... Gross heating value of gas, B.Th.U. per cubic foot ..... Ammonia per ton, lb.......... Coke data:— Went through the sieve, p. cent. The remainder, after a fall of 140 in., gave— Lumps above 1’8 in., p. cent. Nuts, 1*2 to 1‘8 inch, p. cent. Beans and peas, 0’2 to 1’2 inch, per cent____________ Dust, per cent_____________ in shed. 10'61 0-21 86-92 the open air. ... 11-11 5’46 ... 82-09 1,185 . ... 1,180 11,972 ... 11,972 mbic feet cubic feet per ton. per ton. 71-9 71-1 3’8 4’4 6’9 8’4 592-7 .. 589’9 6-074 . 5’916 19 .. 32-2 48’0 .. 34-5 25’7 .. 22-9 19-3 .. 31-3 7’0 .. 11’3 T-_ Fio. 17.—Cylindrical Drum Grooved Barrel and Overlapping. 850 yds. of 2" rope. i o o o o/'oA o o_ 37 Coils Stu Dia.oF Rope 2‘Pitch oF Grooves 2%i -------------__________________._____ Centres oFPithead Pulleys ___ _____________15' 8"______________ Rope \\Drum I372- \ She ft ZA F t372 -1 •• Centres of Pithead Pulleys 9‘ IQ" ----------------fS'.Q------------------- Fig. 18.—Cylindro-Conical Drum Grooved Barrel and Overlapping 850 yds. 2j" rope. , Pope 2Dio. > - 2 ’• 6 3/+"— L - - - - 2 '• 63/* "— Pitch of Grooves 2s/ie of2! ■ against the side of coil 2, fig. 9, before resting on the top coil 2, it will not drop into position between the two under-coils, but will spring across to the crown of the succeeding under-coils. The relative diameters of the rope and the drum are therefore the primary factors in the matter. To enable the rope to drop into position between two under-coils a distinct .bend must occur in the rope. Its flexibility therefore comes in. So far as the diameters of the rope and drum are concerned, the maximum permissible size of the angle ABC should be capable of being determined either mathematically or graphically, and it is possible that all ordinary ropes may be sufficiently flexible to leave such determination prac- tically unaffected. The writer would be glad if some member would look into this matter with a view of pre- paring a formula to meet different sizes of drums with differ ent sizes of ropes,. In the meantime the writer gives a few actual instances of success and failure under different condi- tions :— Example 1 (fig. 12).—A 6 ft. diameter drum used for sinking with a 1 in. locked coil rope, arranged for the rope to mount at C, coiled satisfactorily at an angle of one in 33. Proportion of rope diameter to drum diameter, one to 72. Example 2 (fig. 13).—A 5 ft. 6 in. diameter drum, used for sinking with a 1 in. locked coil rope, arranged to mount at C, coiled satisfactorily at an angle of one in 28. Proportion of rope to drum diameter, one to 66. Example 3 (fig. 14).—A 13 ft. diameter drum, used temporarily for sinking with a 1 in. locked coil rope, arranged to mount at C. Failed to coil properly until the rope had run across to C1. Proportion of rope to drum diameter, one to 156. Under these conditions it quite failed to lap property at one in 42, and only coiled property on reaching an angle of one in 94, when too late for the drum to hold the required length of rope. Example 4 (fig. 15).—A 24 ft. diameter cylindrical drum, with a wrought iron grooved barrel, grooves 1 in, deep, used for permanent winding with a 1 in. diameter locked coil rope (5J circumference), gross load 22| tons from 850 yds., arranged to coil in grooves from a to A and from A to C. Proportion of rope diameter to drum diameter, one to 174. Works satisfactorily in grooves at an angle of one in 82, and would probably work equally well, if necessary, at a materially greater angle. Example 5 (fig. 16).—A 15 ft. diameter drum with a cast iron grooved barrel, grooves -J-in. deep, used for permanent winding with a 1J in. diameter (9| circum- ference), Lang’s lay rope, gross load 10 tons from 400 yds., arranged to coil in grooves for first layer from a, and to mount at C. Proportion of rope to drum one-third of a coil on the first occasion and a second one- third on a subsequent occasion, the wear would be distri- buted over three series of points throughout the length of the rope. To enable this to be readily done, loose rope reels inside the drum barrels to take some spare rope are desirable. In figs. 17 and 18 the writer gives sections of two drums so arranged, which also have other points of interest. ________________________________ Manchester Steam Users’ Association. — The annual report of the committee of management for 1913 states 'that on December 31, 1913, there were 2,138 members of the association, owning 4,529 works and 10,079 boilers. These included 96 collieries. As many as 9,942 “internal,” “ flue,” and “ entire ” examinations of boilers were made, the highest number ever attained. No boiler under the asso- ciation’s care burst during the year, and the committee are glad that they can say at the end of 59 years that no life has ever been lost from the explosion of any boiler which the association has inspected and guaranteed as safe. Out- side its ranks the association has noted throughout the United Kingdom during the year the occurrence of 57 explosions, killing 35 persons and injuring 41 others. Of these, 13, killing 18 persons and injuring 10 others, may be termed “ boiler explosions proper,” while the remaining 44, killing 17 persons and injuring 31 others, may be termed “ miscellaneous ” explosions, i.e., those arising from steam pipes, stop valves, kiers, drying cylinders, bakers’ ovens, economisers, etc. Under the Boiler Explosions Acts, 1882 and 1890, reports have been received up to the time of going to press, since the publication of dur last report, of 74 preliminary enquiries by the Board of Trade. Of these, 10 have been followed by formal investigation, and costs varying from T20 to T75, and amounting in the aggre- gate to J6195, were ordered to be paid by parties found to be in default. In six cases no order was made as to costs. The 1 ‘ special work ’ ’ department has had an exceptionally active year in preparing specifications for new boilers, steam pipes, economisers, calorifiers, etc., and in superintending the construction and witnessing the test at the makers’ works. The attention of steam users is specially called to this service, which is found to be of much practical value when boilers are required for use at home or abroad. The summary of tests as to the strengths of stayed flat plates, published in the chief engineer’s memorandum last year, has been appreciated in engineering circles. A similar sum- mary of the failures of steam pipes on board steamers due to vibrations was laid before the Institute of Naval Archi- tects by the chief engineer, and will be extended to steam pipes on land in the next published memorandum. A series of tests on a torsion fatigue testing machine has now been completed, and a new machine on which fatigue tests can be conducted, both as regards torsion, bending, and push and pull stresses, has been fitted up on the association’s pre- mises, and will shortly be available for the carrying out of such tests. These data apply, of course, only to the particular kind of coal in question, but it is interesting to note that in this case the yield of gas and the heating value of the gas pre- sented no marked difference, but that the coke from the coal stored in the open air was decidedly inferior to that from the coal stored under cover. In other respects, the results were substantially the same, except that there was more liquor from the damper coal. The research station has begun an investigation into the differences between fresh coal and stored coal. ______________________ PARKIN’S SIGNAL BELL. The accompanying drawing shows an indicating signal bell designed with a view of preventing enginemen wind- ing without having had a signal given. The action is as follows :—The hanger-on pulls his lever at the pit bottom the necessary number of signals, this rings the bell, and each stroke is registered by the index on the plate. The index stands at 0 when there has been no signal. The vertical lever is connected with, the winding indicator by a cord or small chain, and during the time the engine is winding, the lever should be drawn to the left, about two inches, and allowed to go back to its place again. This releases the index back to 0 ready for the next signal; this is easily done in a variety of ways. This arrangement may be used in connection with a dial indicating the number of complete drum revolutions and the number of winds. The bell itself consists of a gong with a steel disc or wheel behind. The wheel has four arms, to any one of which the wire or cord can be attached. The makers are Messrs. Archibald Baird and Son Limited, of Hamilton, N.B.