May 1, 1914. TSE COLLIERY GUARDIAN. 965 A Modern German Colliery Plant. THE EQUIPMENT OF THE FRIEDRICH HEINRICH COLLIERY. By P. BUSSING, from Gliickauf, (Continued from page 894). Winding Engines. The intake shaft (No. 1) is served by a cylindrical drum winding engine and by a Koepe pulley engine, whilst the ventilating shaft (No. 2) is served by a cylindrical drum machine only (fig. 12). To enable the exhaust steam to be utilised to the utmost in the power house, all three engines are of the two-cylinder, non- compound type, and, apart from the main shafts, are identical throughout, having 42 in. cylinders and 72 in. stroke. When run under the most economical con- ditions of expansion, they are capable of raising a net load of 5| tons from a depth of 500 to 800 m., with a maximum rope velocity of 65 ft. per second, but are also sufficiently powerful to deal with a load of 8 tons of stone at correspondingly reduced velocity. The cylin- drical rope drums have a diameter of 26J ft. and a net width of nearly 6 ft. The spokes and shell are of strong, well-stayed ironwork, and the facing is of elm with machined grooves to take 2-| in. rope. The brake-ring, of angle iron, is secured to the shell in such a way that no distortion or loosening is possible. A wrought iron ring to take up the wear is riveted on to the angle iron. The distance between the brake cheeks and the ring is only in. when the brakes are off, and therefore the brakes can be applied without appreciable shock or noise. The Koepe pulley (22 ft. in diameter) of the second engine at No. 1 shaft is made in two parts, of cast steel, and carries a 1,000 m. rope (four laps). The width of this pulley is 42 in. and it is therefore provided with a double set of elliptical arms, so that bending is impossible. The two halves of the pulley are secured by powerful bolts, shrunk-on rings and shrunk-on fishplates. The engines embody all the chief points of up-to-date practice, the cylinders, pistons and stuffing boxes being specially constructed to stand the high steam temperature of 300 to 350 degs. Cent, and 13 atmospheres pressure. Provision is also made to allow free expansion of all the parts in contact with steam. The cylinder’ valves are arranged above and below the cylinders, the clearances are small, and loss of heat by radiation is minimised by lagging. The valves are operated by cam gearing of the inverted type, short movements of the gear lever corresponding to large admission, whilst longer movements increase the cut off. This arrangement is found very satisfac- tory for manceuvring the cages and as tending to compel the enginemen to run their engines economically —early cut-off and proper utilisation of the expansion. The valve gear is operated in the usual way, by a steam- controlled device and oil dashpot. The engines are fitted with the Gutehoffnungshiitte overwinder (fig. 13), which also indicates the position of the cages and controls the starting, maximum and final speeds. The gear shaft a operates the depth indicator b by worm gear and the governor c by pinion gearing. Both these devices act on the double lever d, which, by means of the link e releases the pawl lever f, thus allowing the counterweight lever g to turn. This move- ment raises the two rods fe1 and A2, and moves the gear lever i into the middle position from either side by means of the lever fc, thus shutting off the steam. The same arrangement is provided for operating the brake lever. As the cage approaches bank, any incorrect movement of the gear lever (which is connected with the springy double lever m by rods) is limited by one or other of the adjustable stops ll, V, though the springs will give way for the gear lever to be moved in the right direction. Starting in the wrong direction is therefore impossible. When the engine attains the maximum permitted speed, the governor operates the control slide valve, through the rods n, o, and p, so that the cut-off is adjusted to the extent necessary to maintain that speed, without any movement of the gear lever being required. When the slowing-down stage is reached, the rollers of the roller lever ascend the cam surface r, and thereby raise the pivot of the lever d. Should the engine not slow down accordingly, the link e then rises and releases the pawl f, thus returning the gear lever to its middle position and shutting off the steam. In the event of the engine not slowing down in consequence of these operations, the brake lever is actuated in the same way as the gear lever, and the brakes are applied with pro- gressively-increasing force. In the case of an overwind the brake pawl is operated by the nut of the depth indicator in the usual manner, and the brakes are applied with full force. The pawls for the gear lever and brake lever are set back into position when the engineman pulls out the starting lever or draws back the brake lever. A special advantage of this overwinder is that the engineman has full control of the valve gear and brakes all the time, and can, in particular, reverse with a full head of steam at any moment. Each engine is fitted with independent steam and drop-weight brakes, and the pawl retaining the weight can be released instantaneously by hand, from the engine- man’s stand. The vertical cylinder of the steam brake is situated below the engine-room floor, and in the case of the Koepe pulley engine, is provided with a special brake-pressure regulator, enabling that pressure to be varied in accordance with the movement of the brake lever. This arrangement lessens the wear on the brake cheeks, by preventing sudden shocks, and also greatly Z I Fig. 12.—Winding Engines. Fig. 13.—Overwinder. nun er th •irczn. ■i facilitates manoeuvring the cages. The steam is shut off by a stop valve, mounted behind the large steam trap of the engine, and opening to full aperture with a single turn of the hand wheel, so that there is no chance of the engine being kept running under constantly throttled steam, as sometimes happens when the valve spindle has to be turned several times in order to open the valve fully. Heat Accumulator. This accumulator (Harle-Gutehoffnungshiitte type) has an expansion capacity of 24,700 cubic feet. When the bell descends to nearly its lowest position, the turbine receives live steam exclusively, no exhaust steam being drawn from the accumulator. To prevent collapse of the accumulator through the atmospheric pressure, if, from any unforeseen cause, the turbine should continue to draw from the latter, provision is made for the admission of live steam into the accumulator, should such a contingency arise, and in the event of this provision also failing, the further descent of the bell opens an air valve and admits air into the accumulator. In proportion as the bell rises under the pressure of exhaust steam admitted into the accumulator, it gradually increases the supply of exhaust steam to the turbine, the supply of live steam being correspondingly reduced until shut off altogether. If the supply of exhaust steam exceeds the momentary requirements of the turbine, the safety valve of the accumulator blows off when the bell has reached the upper limit of its course. The chief superiority of this type of accumulator over the Rateau is that the internal pressure is uniform and about two-tenths of an atmosphere lower than in the latter apparatus. This means that a smaller back pressure is exerted on the primary engines, so that the steam consumption is more economical, and there are no fluctuations of back pressure to act unfavourably on the manceuvring of the winding engines. At the same time there are no fluctuations of pressure transmitted to the turbines, which fluctuations are particularly undesirable when turbines are run in parallel connection. Moreover, experience has shown that the losses by condensation, owing to the large surface of the accumulator, are not so great as expected, the means of insulation now avail- able being sufficient to prevent this inconvenience. This method of utilising the exhaust steam has proved highly satisfactory in constant work. The more active the winding operations, the more exhaust steam supplied to the mixed-pressure turbine, and the greater the amount of electrical energy generated by that exhaust steam, the consumption of live steam being corre- spondingly smaller. This compensates, in a measure, for the higher steam consumption of the winding engines, with the result that the extra demand on the boilers when winding is increased is hardly noticeable.