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This is an arrangement f or regulating the amount of air which is supplied to a coal-burning locomotive, and supplying the air at the requisite speed and pressure by means of a fan blast. Our engravings illustrate fully the invention. Fig. 1 being a longitudinal vertical and central section, and Fig. 2 being an inverted plan of the improvement. The great difficulty which has hitherto been experienced in the use of coal-burning locomotives is, that anthracite requires a strong blast to consume it quick enough to throw out the requisite quantity of heat, and the blast created by the escape steam is not enough for this, therefore some extraneous means, such as a fan-blower, has to be employed. This invention consists in an arrangement of such a fan-blower placed underneath the boiler of the locomotive, and connected with pipes which are i provided with valves, and so arranged that j the fire may be supplied with a greater or less j quantity of air as desired, and when neces- ' sary a reverse draft brought down through the flues and the upper part of the fire chamber, in order to lessen the temperature of the boiler. A represents the boiler of a locomotive. B is the smoke-pipe. C represents the flues which pass longitudinally through the boiler from the fire chamber, D, to the smoke pipe, B. Underneath the boiler a fan, F, is placed. This fan is fitted in a proper box, G, which connects at the center of each side, with a curved pipe, H, the pipe being connected with a pipe, I, which is fitted within the smoke-pipe, B. The way in which pipe, I, is made to communicate with the fan-box is plainly shown in Fig. 2. A valve, a, is fitted in pipe, I, near its junction with pipe, H. From the periphery of the fan-box, G, two pipes, J K, project, the lower pipe, K, passes into the fire chamber below the grate, L, and the end of pipe, J, communicates with the open air. The pipes, J K, have valves, b b% fitted or placed on them; these valves, b b\ are placed on a common rod or axis, and in reverse positions the valve, 6^, being open, when b is shut, and vicQ versa. M M represent two pipes, one end of which communicates with the fire chamber above the grate, L, and their opposite ends are open to the sides of the fan-box, G. Each pipe, M, is provided with a valve, c, the valves of the several pipes all have rods, li, attached, which rods extend back at the sides of the fire chamber and within reach of the engineer. The fan, F, is driven by belts or chains, e, from the truck axles, the belts being enclosed within proper cases to exclude dust, and thereby prevent the wearing or " cutting out" of them. The operation is as follows ;—When an intense heat is required, the valves, c c, in the pipes, M M, are closed, and the valve, 5, in the pipe J is also closed, V in the pipe, K, being open. The fire will then be supplied with a blast which passes down the pipe, L, through ( the curved pipe, H, into the fan-box, G, and / thence through the pipe, K, into the fire ^ chamber, D, below the grate, L, and through the flues, C, into smoke-pipe, B—see arrows. The strength of this blast may be regulated by adjusting the valves, a b\ When the temperature of the boiler requires to be reduced, the valves, a b\ are closed, and the valve, &, in the pipe opened, and the valves, c, in the pipes, M M, also opened. The blast will thei pass in the direction of the dotted arrows, down the smoke-pipe, B, thr ough C into D. from thence through M into G, where the fan. discharges it into the atmosphere through the pipe, J. This reverse diaft cools the flues, and so reduces the temperature of the boiler. By this arrangement the fire of a coal-burning locomotive is placed entirely under the control of the engine driver, and the heat can be graduated as desired. This plan is a great improvement on the usual one, which is closing the flues and ash pan with dampers. It is the invention of J. M. Hartnett, of Waucon-da. III, from whom any further information can be had. It was patented July 21, 1857.
