330 EXPLANATION OF THE PLATES. 



PLATE III. 



This plate represents Brunton's apparatus for feeding furnace-fires by means of 

 machinery. The general principles of the method and its advantages have been 

 stated, (art. 250.) and it only remains to describe the parts of the figure. The 

 apparatus was added to two boilers of Boulton and Watt's construction. To the 

 original boilers A A, two additional boilers B B, are attached, which are prepared 

 for the purpose of being over the revolving fire-grate ; the smoke from which 

 passes over and under the bridges d d, and round the boilers A A, by the flue C ; 

 and D D are the flue-doors. The coals, broken to a proper size, are put into the 

 hoppers E E, and fall through the openings F F, and through the top of the 

 boiler to the grate. The door H, to examine or repair the fire-place, is attached to 

 the boiler by a cement joint. The additional boilers are connected to the main 

 boilers by the steam pipes G G. 



To clear the dust away that falls over the edge of the revolving grate, there are 

 doors at I I ; they also admit a small quantity of air to the burning fuel. The 

 axis K of the grate is turned by the pinion and wheel at L, turned by the upright 

 shaft N, which receives its motion by the shaft R from the engine. 



The pivot of the shaft N, and of the spindle K, are in the foundation plate M. 

 The grate bars are surrounded by fire bricks h, and a thin hoop projects below the 

 frame, and moves in sand in a trough /, and prevents air entering by any other 

 passage than through between the bars : a scraper attached to the grate, and 

 consequently moving with it, keeps the channel i clear of dust. 



To regulate the fire, the chains S S are connected to the damper chains, and 

 raise or depress the wedge U by the lever T, and thus increase or diminish the 

 supply of coals according to the force of the steam. (See art. 257.) 



The feed pipe O, with its stone float c and balance /, are as in other boilers, (art. 

 251.) The gauge-cocks are at Z, the man-hole at a, with an internal valve at b; 

 the safety valve is at V, with a pipe Q to convey away the steam ; P is the pipe for 

 conveying steam to the engine, with a self-acting stop valve W, to prevent the 

 steam passing from one boiler to the other when both are in action ; and X Y is a 

 lever handle for closing the aperture when only a small supply of steam is 

 required. 



The construction will admit of considerable variation ; and its advantages in 

 saving fuel, in regularity of action, and in consuming the sooty matter of smoke, 

 render it a desirable addition to a large boiler. 



