EE

(16) The Kuhn coal-compressing machine, for charging coal into coke-ovens, is intended to produce a strong coke, and enable otherwise unsuitable kinds of coal to be turned to account.

(17) The Express underground pumping-engine will lift 418 gallons of water to a height of 2,500 feet at 146 revolutions per minute. It is driven by a three-phase electric motor. This pump possesses the advantages of high speed, simplicity, and takes up little space, and is, therefore, very suitable for underground work.

(18) Messrs. Haniel & Lueg exhibited a large underground pumping-plant intended to deal with water from a number of mines at a central point. It is capable of pumping 5,500 gallons of water per minute to a height of 1,638 feet. The tripleexpansion-engine has a high-pressure cylinder 374 inches in diameter, the middle cylinder is 59 inches in diameter, and the two low-pressure cylinders are each 65 inches in diameter; the stroke is 67 inches; and working at a speed of 60 revolutions per minute, it has a piston-speed of 11 feet per second, a speed which has not been reached in any other pump. The machine stands in an engine-room not exceeding 26 feet in breadth, and the consumption of steam will not exceed 148 to 15 pounds per horsepower-hour measured in the water raised.

(19) The Tomson compound overhead winding-engine, of 800 horsepower with two spiral drums, exhibited by the Harpen Colliery Company, is designed for winding from a depth of 4,900 feet at the Preussen II. colliery. This engine is a duplicate of that which has been working for some years at the Preussen I. colliery. The cylinders work upon an intermediate shaft, which is coupled by means of connecting-rods to cranks on two spiral drums, placed one behind the other. This arrangement avoids the excessive weight of two massive drums being placed on a single shaft, and obtains a better lead. for the ropes. The diameter of the cylinders is 32 inches and 45 inches respectively, and the stroke is 8 feet. The conical drums range from 18 feet at the smallest diameter to 33 feet at the greatest, and the breadth is 11 feet 4 inches. A remark was made that "this engine, perhaps, represents the last word of

the nineteenth century in winding-engines, but not the first of the twentieth century," and the latter phrase may perhaps be applicable to the electric winding-engine described in the following paragraph.

(20) The electric winding-engine, for the Zollern colliery of the Gelsenkirchen Colliery Company, is intended to raise 1,000 tons of coal in 6 hours, by 2·13 tons of coal at each wind, from a depth of 1,638 feet, with a maximum velocity of 65.6 feet per second. The drum is on the Kope system, that is to say, the rope passes round the drum for about two-thirds of its circumference in a groove, and the two ends of the ropes are attached to the two cages. This system is particularly suitable for electrical construction, on account of its narrowness. The diameter of the drum was fixed at 197 feet, with the object of securing sufficient adhesion for the rope, and at the same time reducing the size of the electric motors by obtaining a higher velocity. The arrangement is very simple:-On each side of the drum, two motors are placed, each capable of developing 1,400 horsepower on the main shaft, the ends of which are supported by two broad pedestals. The separation of the electrical driving into two parts was selected so that by running either in parallel or in series it is possible to attain the maximum velocity of 66 feet per second or 33 feet per second; and also so that in case of accident to one of the motors, the other will work the engine with a somewhat reduced load. By means of an arrangement of storage-batteries and through the excitation of the field-magnets, the motors can be run at other speeds without any waste of energy, for instance 6, 12, 16, 20, 26, 33, 40, 52 and 66 feet per second. The machine is fitted with a Baumann indicator, which regulates the maximum-velocity of the load as it approaches the surface, and should this velocity be exceeded the brake is automatically brought into action. The continuous current at a pressure of 500 volts is supplied from steam-driven generators, working in connection with an an arrangement of storage-batteries, which permit of an adequate reserve of energy an important requirement in work of such an intermittent nature as winding and enable the maximum speed to be obtained at starting with a minimum loss of energy. The gradual increase of the voltage is achieved by grouping the

VOL. XXIV.--1902-1903.

41

storage-batteries in four groups, which are separated by little starting resistances. These are connected with the starting mechanism placed in the basement beneath the driver's stand. The shaft of the starting mechanism is carried through the engine-house floor and connected by a rack-and-pinion arrangement to a compressed-air auxiliary-engine, with a working and a regulating cylinder, bolted to a foundation-plate, the pistons being mounted on a common rod. The working piston is operated by compressed air, and the other piston serves to moderate its action. The gearing is on the differential principle, and the motion of the piston-rod brings the distribution-valve into its central position. The compressed-air engine is worked by the driver, and acts on the switch-lever; the travel of the piston is equal to that of the lever in the guide-slot. When the engine is at rest, the lever is inclined towards the driver; when the lever is placed in the right-hand catch the engine will raise the right-hand cage or vice versa. Another lever, placed beside the switch-lever controls the compressed-air brake, and this is made to act only when the switch-lever is placed in the nocurrent position. The compressed-air cylinder acts on four brake-blocks, and is operated either by the hand-lever, or automatically in connection with the Baumann safety-indicator. In case the air-brake should fail to act, the driver can stop the engines by a counter-weight brake.

(21) The Tomson boiler consists of two Cornish-type boilers, which together have a heating-surface of 270 square feet, and a water-tube boiler with a heating-surface of 1,564 square feet. The Cornish boilers are 5 feet 10 inches in diameter and 13 feet 1 inch in total length, with a capacity of 424 cubic feet; while the tube-boiler has a capacity of about 250 cubic feet. The latter contains 96 tubes, each 17 feet long and 33 inches in external diameter, two welded water-chambers, and, connected with these chambers, a surmounting steam-chamber, 21 feet 4 inches long and 3 feet 7 inches in diameter. Under normal working conditions 1 square foot of heating-surface will evaporate 36 pounds of water per hour. At the Preussen I. colliery, 9 pounds of water have been evaporated in a Tomson boiler by 1 pound of coal. The combination of internal firing with the water-tube boiler enables the heating gases to be

utilized to their fullest extent, and as the live flames do not come directly into contact with the tubes, the latter very rarely exceed a temperature of 800° Fahr., and there is, therefore, very little wear upon them.

(22) Messrs. Göhmann & Einhorn showed various lavatory and bath-appliances specially intended for use at collieries, including elaborate baths and showers for the higher collieryofficials; similar baths of a simpler kind intended for the use of the overmen, deputies, etc.; for miners' baths, a sufficient number of shower-baths and a large undressing-room. Alongside the wall of the undressing-room, under the windows, is placed a long sink or trough where the men can wash their hands and faces. The miners' clothes are also left in this room, where they are drawn to the roof by means of cords and pulleys. Two heat-radiators are placed in the roof in order to dry the clothes.

In another room is shewn apparatus for cleansing and disinfecting clothes. There is also a model workmen's closet, made in white glazed earthenware.

SHAMROCK COLLIERIES, HERNE.

The Hibernia Mining Company own eight collieries and a total area of coal-field of about 25 square miles. In 1901, they employed 13,667 men and boys, and had an output of 3,573,050 tons of coal.

The Shamrock III. and IV. colliery is justly regarded as one of the model collieries in the Westphalian district. The two shafts are each 16 feet 5 inches in diameter. The upcastshaft is not used for coal-winding; but the downcast-shaft is divided, so as to allow of four cages, actuated by two separate winding-engines, with cylinders 36 inches in diameter and 6 feet 63 inches stroke. One winding-engine is compound, and the low-pressure cylinder has a diameter of 4 feet 3 inches. The cages have four decks, each deck containing two tubs with a capacity of about 11 cwts. The heapstead is arranged with a 'double banking-platform, the upper being connected with the lower deck by means of drop-cages. The nuts and small coal passing from the screens are conveyed to two Baum washers,

1

one on either side of the heapstead, and these have a capacity of 150 to 220 tons per hour respectively.

The ventilation is effected by two Geisler ventilators, one being held in reserve. These ventilators are 14 feet 9 inches in diameter, and exhaust 212,000 cubic feet of air per minute. under a depression of 35 inches. In the same engine-house are four Dingler water-column air-compressors, capable of yielding together 424 cubic feet of compressed air up to a pressure of 5 atmospheres per minute.

The coking-plant comprizes two batteries, each of 60 OttoHoffmann ovens, and the bye-products are recovered at one battery, while the hot gases from the other are used for heating the boilers.

An experiment was conducted to shew the efficiency of the WalcherGiersberg pneu

matophor, an

improved lifesaving apparatus. This apparatus differs from the

original Walcher

pneumatophor: (1) In the substitution of dry alkali for caustic soda, which it was found in practice was dangerous, as it caused severe burns if any escape of the liquor from the breathing-bag took place, several workmen having been severely burned; and (2) in the introduction of an automatic regulating-valve between the oxygen-cylinders and the breathing-bag: it possesses the great advantage that the wearer has no occasion to trouble him