NEWS ITEMS.

PAGE'S WEEKLY

An Illustrated Technical Weekly, dealing with the Engineering, Electrical, Mining, Iron and Steel, and Shipbuilding Industries.

DAVIDGE PAGE, Editor.

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Royal Coal Commission.

As we go to press the Final Report of the Royal Commission on Coal Supplies (Part I., General Report) comes to hand. Following the precedent of the Coal Commission of 1871, the limit of practicable depth in working has been set at 4,000 ft., and the minimum workable thickness at 1 ft. The available quantity of coal in the proved coal fields of the United Kingdom is estimated at

100,914,668,167 tons.

Of the available coal, no less than 79'3 per cent. is contained in seams of 2 ft. thick, and upwards. In addition to the coal within 4,000 ft. of the surface there are in the proved coalfields considerable quantities lying at greater depths. Whether this coal is recoverable or not depends of course upon the maximum depth at which it may be found possible to carry on mining operations. The estimated quantity of this coal is

5,236,433,980 tons.

The geological committee, appointed to inquire into the productive measures known or believed to exist outside the areas dealt with by the district commissioners, report that the amount of coal which way be expected to be available in the concealed and unproved coalfields at depths less than 4,000 ft. is 39,843,000,000 tons.

The present annual output is in round numbers 230,000,000 tons.

Almost all the opinions given to the Commission on the general question of coal cutting machines compared with hand labour are in favour of the former, but these opinions are accompanied by many qualifications and exceptions. Other possible economies are suggested, and the evidence shows that seams which cannot now be worked at a profit will in future be rendered profitable by washing, sorting, coking. and briquetting the coal, or converting it into gas, so that no small coal need be left in the mine. With this and other aspects of this important report we hope to deal with in our next issue.

It is announced that Marconi's Wireless Telegraph Company, Ltd., has entered into an agreement with the Oceanic Steam Navigation Company, Ltd. (the White Star Line) for the equipment of six of the White Star Line vessels-the Oceanic, Celtic, Baltic, Cedric, Majestic and Teutonic-with Marconi wireless apparatus.

British Standard Pipe Flanges.

We have just received from Mr. Leslie S. Robertson (secretary) the latest report of the Engineering Standards Committee, dealing with "Pipe Flanges." The publication is one which can scarcely fail to interest a large section of the engineering world, and as will be seen from table IV., reproduced herewith, it is drawn up in great detail. As regards classification of pressures, the committee recommend that flanges, etc., should be standardised in four classes, as follows: (1) Low-pressure standard, for steam pressures up to 55 lb., and water pressures up to 200 lb. per square inch; (2) intermediate-pressure standard, for steam pressures over 55 lb., but not exceeding 125 lb. per square inch; (3) high-pressure standard, for steam pressures over 125 lb., but not exceeding 225 lb. per square inch; (4) extra high-pressure standard, for steam pressures over 225 lb., but not exceeding 325 lb. per square inch.

It was decided that the number of bolts used should in all cases be a multiple of four, and that the boltholes should be so placed that spaces between them are bisected by the main centre lines. The Committee are quite aware that in the case of flanges for certain sizes of pipes-and especially of those for 2-in. pipes -the adoption of multiples of four for the number of bolts involves some change of practice; but, after carefully discussing the opinions and experimental data brought before them, they are convinced that the advantages resulting from the adoption of such a principle outweigh the disadvantages.

For determining the sizes of bolts, it has been assumed that, in the case of a joint just on the point of leaking, the full working pressure might be exerted over the area of a circle just touching the inner sides of the bolt-holes, and the sectional area of the bolts at the bottom of the threads has been fixed to meet this contingency. In the case of the smaller sizes of pipes, allowances have also been made for undue stresses in making the joints. It is considered desirable that all nuts should be chamfered on the side bearing on the flange, and that the bearing surfaces of the heads, nuts, and flanges should be trued.

The sizes of bolt-holes decided upon were: For -in. and -in. bolts the diameter of the holes to be in. larger than the diameters of the bolts; and for larger sizes of bolts,

in.

Practically the sizes of flanges are governed by the necessity of adopting such diameters as will meet the requirements of makers of stop-valves and similar fittings. The diameters decided upon by the Committee are the smallest which will satisfy these.

Tables I. and II. deal with the dimensions of the

British standard pipe flanges for the different pressures specified above. Table III. shows the dimensions of British standard welded-on flanges for pipe lines for working steam pressures up to 125 lb., 225 lb., and 325 lb. per square inch. Table IV. gives the dimensions of British standard short bends and tees of cast metal for all pressures up to 325 lb. per square inch, and table V. the dimensions of British standard long bends of wrought iron and steel.

The Committee on Pipe Flanges was as follows: Mr. William H. Maw (chairman); Mr. W. E. Smith, C.B., and Engineer-Commander A. R. Emdin, R.N., representing the Admiralty; Messrs. E. B. Ellington, Henry Davey, W. H. Patchell, Andrew Laing, John Steven, J. Dewrance, R. E. Atkinson, T. Hurry Riches, Frank Herbert, J. Hopkinson, Robert Hopkinson, T. Harris Spencer, and G. Watson.

A New Crushing Machine.

We illustrate, by the courtesy of the Patent Clêro. Crusher, Ltd., of 65 and 66, Chancery Lane, London, W.C., a new form of crushing machinery, which is likely to play an important part in mining operations. This is constructed on the principle of centrifugal force and consists mainly of a shaft revolving with a velocity of 1,000 to 1,500 revolutions per minute, to which shaft are keyed two heavy flanges or discs that revolve with it and act as flywheels. In these flanges are journalled a number of successive beaters, usually six, in the shape of cranked axles. The bottom of the apparatus is constituted by two curved perforated plates, each covering one-fourth of the circumference of a circle, and serving as screens to allow of the escape of the disintegrated matter. They are formed in two halves to allow of their being easily withdrawn and replaced without interfering with any other portion of the apparatus. Several steel cushions placed within the rear face of the casing assist in the process of disintegration. A casing and hopper for the introduction of the material to be disintegrated complete the crusher. The casing, with the hopper, pivots round a hinge to facilitate the inspection and cleansing of the apparatus, and the replacement of the beaters and screens.

On the shaft being set in motion, the beaters assume a radial position with respect to the shaft, and strike

THE PATENT CLERO CRUSHER.

the material introduced into the hopper, slightly clearing the semi circular screen fitted in the lower part of the casing.

The particles thus struck are violently thrown against each other, and also against the steel cushions within the casing, and are rapidly reduced to the required degree of fineness when they escape through the screen to be carried away.

This form of crusher claims attention by reason of its simplicity, facility for exchanging parts, portability, small wear and tear, great output and economy of power. It is made in two sizes, 1 and 2, having the following dimensions:

Crusher No. I weighs about 1,500 lb., No. 2 about 2 tons and they can also be made in sections. The power required for No. 1 is from 4 to 8 h.p. according to the substance to be ground and the degree of fineness required. The larger size requires from 25 to 30 h.p.

With the above-mentioned h.p. the smaller machine pulverises from 2 to 4 tons per hour of such substances as plaster of Paris, barites, cement clinker, slag, glass, coal, pottery ware, moulders' sand, quartz, mineral ores, etc., etc. The output of the other machine is from 5 to 7 times as large, and we are assured that it will pulverise in one hour as much as 30 tons of gypsum for plaster of Paris, and over 15 tons per hour of such substances as steel slag, quartz, mineral ore, etc.

We understand that some interesting experiments will shortly be made with this appliance. In the meantime, we note that the municipality of Paris has recently granted a concession for the pulverisation of the town refuse of Paris with this form of crusher.

At Paris it has been found that a No. 2 Crusher consuming 30 h.p. will pulverise 10 to 12 tons per hour of town refuse. This refuse is very heterogeneous. It is not previously picked by hand, as it formerly was, but is at once put through the crusher, and it leaves the screen in the form of a blackish mould, perfectly homogeneous, and ready to be delivered at once as manure.

The calendar of the City of Bradford Technical College for the session 1904-1905 is a substantial volume bound in cloth, with some 300 pages of text setting forth detailed particulars of the numerous day and evening classes. The work is divided into three main sections, presided over by Professor A. F. Barker, Professor W. M. Gardner, and Professor G. F. Charnock, M. Inst.C.E., M.I.M.E.

A Destructor Test.

An interesting report by Mr. Stromeyer (of the Manchester Steam Users' Association) has just been received, dealing with a two days' test of the Nelson Destructor. This report has an added interest in view of the calculated composition of the fuel part of the refuse from an analysis of the waste gases. On these tests a Callendar electrical recording pyrometer was fixed in the downtake of the Lancashire boiler connected with the destructor. The accompanying diagram for a week's run is interesting as showing that the temperature during the week-end banking did not fall below 300 deg. F. in the downtake. It will also be noted that the effect on the temperature of every operation of feeding, clinkering, clearing ashes, banking, etc., is duly recorded.

The destructor was designed and erected by Messrs. Meldrum Bros., Ltd., of the engineering works, Timperley, near Manchester, and is of their front feed regenerative simplex type. It has one continuous grate 20 ft. by 5 ft. in a furnace chamber 22 6 ft. having four separated

ft. by and closed ashpits, separately supplied with hot air under pressure. following is a brief summary of the trial:

The

Wednesday. 14.1.03. 9.35-6.35 9.00 134 2

ture Refuse

Tuesday. Wednesday.

Corresponding tempera

F...

358 2..

357-8

45,416.

43,400

5,837

4,822

63,723.

67,485

8,191..

7,498

1,419

1,555

burnt during trial lb. Refuse burnt per hour, lb... Feed water supplied lb... during trial Feed water supply per lb. hour Feed water supply per lb. lb. of fuel Moisture in steam per cent. F.. Temperature of feed Evaporation per lb. of fuel from and at 212 deg. F. including steam jets,lb. Table II. included in the report, contains details which were only obtainable by making continuous and complete gas analysis, including the moisture in the waste gases. With the help of the information thus obtained it was possible to calculate the chemical composition of the fuel (it contained on an average 314 per cent. carbon, and 0.5 per cent, hydrogen), its calorific value (4.6 evaporative units) and the weight of waste products per pound of refuse (5.6 lb.) The heat utilised in the were then calculated. steam production of (exclusive of the blowers), amounted to 36 per cent., which must be considered a high duty when it is seen that the carbon and the heat in the ashes account for a loss of 20 per cent. heat carried up the chimney amount to an average of 19.3 per cent. which is reasonably low.

The