The Mechanical Handling and Storing of Material

THE AUTOMATIC WEIGHING OF MATERIAL 715 piece and thence into either sack as required. These machines are best fitted with glass-panelled covers, which not only obviate any escape of dust, but also prevent any tampering with the mechanism. Avery’s Automatic Scale for Weighing Coal, Coke, Minerals, and Similar Materials.—This weighing machine is very similar to the one for grain already described, and is illustrated in Figs. 1023 and 1024. A machine with a hopper capacity of 2 cwt. per discharge is usually installed for weighing small coal in connection with bunkers, etc. It is worked by gravity alone and requires no power either electrical or mechanical to operate it. The machine is fitted with locking gear which prevents any coal passing through unweighed. These automatic coal weighers are chiefly employed in boiler-houses, and the majority of the leading electric power stations at home and abroad are now equipped with these machines. In particular the Glasgow Corporation may be mentioned as Figs. 1025 and 1026. Method of Employing Avery’s Scales in a Boiler-House of the Glasgow Corporation Electricity Department. .among the latest users of the Avery machine; they have installed some forty of them, one of which may be seen in Figs. 1025 and 1026. By means of these automatic weighers the mechanical stokers are automatically fed with coal from the bunkers above, and a record is kept of the total consumption of fuel. The machine is supported on brackets bolted to the girders and has a feed hopper above which is connected by spout with the coal bunker. As the coal passes through the scale, its weight is duly recorded ; it then falls into the discharge hopper below, and thence into the spouts which feed the stoker hoppers. Charge after charge is weighed and delivered to the stoker hoppers until the spouts leading to them are quite full, whereupon the weighing machine stops automatically. As soon, however, as sufficient coal has been used by the stokers to clear the shoot, the weighing machine will recommence work, and in this way always adapts itself to the consumption of coal. Instead of fixing a machine beneath each coal bunker, another method is to have one large machine fitted, on a travelling frame which runs on rails overhead and can be