US396947A - Hot-air blast - Google Patents

Description

.(No Model.) W. 0. MILLS.

HOT AIR BLAST. N0. 396 ,9 17. Patented Jan. 29, 1889.

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UNITED STATES PATENT OEEIcE.

\VILLIAMI). MILLS, OF SAN FRANCISCO, CALIFORNIA.

HOT-A| R BLAST.

SPECIFICATION forming part of Letters Patent No. 396,947, dated January 29, 1889.

Application filed June 19, 1888. Serial No. 277,604. (No model.)

To all whom it may concern:

Be it known that I, IVILLIAA'I O. MILLS, of the city and county of San Francisco, State of California, have invented certain new and useful Improvements in Air-Heating Apparatus for the Furnaces of Steam-I-ioilers; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to means for conducting hot air from a casing surrounding the smoke-stack of a locomotive or engine to the ash-box or beneath the grate by the aid of a jet of steam; and the improvements will be fully understood from the following descripti on and claims when taken in connection with the annexed drawings, in which Figure 1 is a front view of a furnace, showing my improvements applied. I ig. 2 is a side elevation, partly in section, of the smokestack and easing surroiniuling the same, with a portion of the pipe which leads therefrom to the ash-pit of the furnace; and Fig. 3 is a perspective view of the jacket or casing removed, with the hot-air conneeting-pipe dctached.

Referring by letter to the said drawings, A indicates a furnace, which may be that of any ordinary or approved construct-ion, hav- The smokc-staclgwl1ich p r( )p erlyl cads from th e :t'urnace, is composed. of tubes l for cz'irrying off the smoke and particles of combustion, and arranged at intervals so as to form between and around them air-passages I). Surrounding these smoke-tubes is a tubularcasing, which is provided in its body with apertures I) for the introduction of cold. air, and this casing surrounds the said tubes l) for a sufficient portion of their length. It should be observed that this perforated jacket or casing may be applied to any tubular smokestack; or, in fact, any smol e-stack-such as at present in use-without altering the construction of the latter in any maimer whatever; and to this feature of construction I attach considerable importance.

In applying the jacket or tubular casing it is simply necessary to slip the same down upon the stack to the base thereof, the upper portion of the said casing being contracted, as shown at II, will approximately engage the outer surface of the stack and thereby retard the free egress of the radiated heat.

' E indicates a pipe, which leads from a suitable point at the base of the casin g surrounding the smoke-tubes to the ash-pit beneath the firebox, as shown at G, so that the cold air which enters the casing through the perforations I) therein and has become heated by contact with the smoke-tubes may be con ducted to the ash-pit and there discharged to feed the tire and promote combustion.

F indicates a steam-pipe, which enters pipe E at its point of connection with the ashchainber. It will thus be seen that by the injection of a jet of steam into this pipe E where it connects with the ash-chamber the air, it is heated in the smoke-stack, will be drawn down through the pipe E and forced into the ash-chamber beneath the fire-grate. This operation will take place when the doors to the ash-chz'unber have been closed and cold air thereby excluded from thc'tirc-chamber.

I am aware that it is not new to feed heated air to a fire in a furnace while excluding cold air therefrom, and that air, superheated steam, and hot gases arising from the combustion-chamber have been forced into the fuel to aid in its combustion.

By this invention it will be seen that the improvements may be applied to any ordinary ecomotive-engine without altering its construction in any manner whatever, it being simply necessary to slip the perforated jacket 0 over the smokestaek and communicate the same with the ash-chamber of the furnace by means of the pipe E.

Having described my invention, what I claim is The coml'iination, with a furnace, of the smoke-stack composed of tubes 1- for the passage of smoke and particles of combustion, the casing O, surrounding the said tubes and having perforations Z) entirely around the same at its upper portion for the inlet of cold air, which passes around the smoketubes, and also having its upper end contraoted to approximately bear against the thrown to draw the heated air in the snookeouter surface of the stack, the pipe E, leadstack or its easing into the -ashpit beneath ing from the lower portion of the said casing the fire, substantially as specified.

below the perforations to the ash-pit of the WM. 0. MILLS. furnace, and the steam-pipe F, entering the \VHJHGSSQSI said pipe E at its point of connection with \VM. LUTHER,

the ash-pit, whereby a jet of steam may be JOHN MILLS.

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