US759235A - Hot-air furnace. - Google Patents

Description

No. 759,235. PATENTED MAY 10, 1904.

P. M. BRUNER. L

HOT AIR FURNACE. APPLICATION FILED JUNE "1, 1901. RENEWED 00113. 1902.

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PAT-EDITED MAY 10, 1904, P. M. BRUNBR. HOT AIR FURNACE. APPLICATION FILED JUNE7.1901. REHEWED 00T.13, 1902.

3 SHBBTS-8HBET 2- no MODEL.

No. 759,235. PATENTED MAY 10, 1904'.

P. M. BRUNER. HOT AIR FURNACE.

APPLICATION FILED JUNE 7. 1901. RENEWED OUT. 13, 1902.

N0 MODEL.

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Patented May 10, 1904.

UNITED STATES PATENT OFFICE.

PRESTON M. BRUNER, OF LEBANON, ILLINOIS.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent N0. 759,235, dated May 10, 1904.

pplicati n file June 7, 1901. Renewed October 13, 1902. Serial No. 127,187. (No model.)

To (ZZZ whom it may concern:

Be it known that I, PRESTON M. BRUNER, a citizen of the United States, residing at the city of Lebanon, county of St. Clair, State of Illinois, have invented a certain new and useful Improvement in Hot-Air Furnaces, of which the following is a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to makeand use the same, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a side elcvational View of my improved hot-air furnace. Fig. 2 is a vertical sectional view through the furnace proper. Fig. 3 is a horizontal sectional view on line 3 3, Fig. 2. Fig. 4: is a horizontal sectional view on line 4 4:, Fig. 2. Fig. 5 is a vertical sectional view through the heating apparatus on line 5 5, Fig. 6. Fig. 6 is a horizontal sectional view.on line 6 6, Fig. 5, and Fig. 7 is a horizontal sectional view on line 7 7, Fig. 5.

This invention relates to a new and useful improvement in hot-air furnaces designed especially for house-heating purposes.

Heretofore furnaces have been provided with mantles into which the heat from the furnace radiates, and air admitted to this mantle has been heated by the said radiated heat. In some instances the furnace proper and heating-drum have been arranged horizontally; but in such instances the furnace has been of such construction that heat radiates, whereby it has been necessary to surround both the furnace proper and the heating-drum by a mantle. The combination of a mantle with a furnace proper presents many objectionable features. It limits the size of the furnace proper, and therefore limits the gratesurface, makes it necessary to feed the furnace from the side, thus rendering a large magazine impossible, necessitates many joints and fittings, presents great liability of gases escaping into the air-space, and in a general manner complicates the construction of both the furnace proper and the heating-drum, eachinterfering with the other to prevent an ideal construction of either.

My object is to overcome the above-mentioned difficulties and to provide a furnace of simple construction and great efficiency.

To these ends and also to improve generally upon apparatus of the character indicated my invention consists in the various matters hereinafter described and claimed.

In my construction the furnace proper and the heating-drum are built as independent structures, and heat is generated in the furnace proper and is carried therefrom to the heating-drum, not wholly or in part by radiation, but entirely by a flue. Preferably the furnace proper is of such construction that no heat radiates therefrom; but all of the heat generated is supplied through the flue to the heating-drum. Thus no mantle for the furnace proper is necessary or desirable, and neither the furnace proper nor the heating-drum interferes with the other, the size of the furnace proper being limited not by an inclosing mantle, but only by the size of the cellar or other space into which the apparatus is to be placed.

In the drawings, the furnace proper consists of an inclosing shell or casing A, the lower part of which is provided with an ashpit door B.

C indicates a casting riveted to the interior of the casing A above the ash-pit and forming a support for the grate-bars I) and for the lining E of the fire-chamber. This lining is perforated or fluted at 0 around its exterior periphery, so as to permit the passage of air down into the ash -pit. The upper inner edges of these tiles E are recessed or cut away to form when the tiles G are in position an air-chamber F. These tiles G rest at their lower edges upon a shoulder formed on the tiles E and at their upper edges against the inner edges of tiles H. The tiles H are supported by the tiles E and G and have their outer edges inclined upwardly and outwardly, so as to form an encircling air-chamber f, while grooves it lead from the coal-reservoir down into the chamber f.

I indicates a coal reservoir or chamber into able manner to the upper end of the shell A. 70 indicates an openingleading from the ex- The shoulders of the tiles E are inclined opposite these openings, as shown, for preventing coal or ashes from lodging thereon and choking the opening. There are a number of these openings 71;, one being preferably opposite the exit-fine for the products of combustion, but none being opposite the intake-opening Zr. The object in this is to force the cold air entering the opening it to travel some distance, and thereby become heated before it mingles with the hot gases and products of combustion passing through the openings in.

It will be noted that the lower portions of the tiles E are thicker at the back of the furnace than at the front thereof, and this locates the fire-chamber eccentrically with respect to the shell or casing A. By the arrangement of the tiles G in conforming to the eccentrically placed fire chamber the airspace F is smallest at a point where the cold air enters through the opening it and largest where the products of combustion pass into the exit-flue L. The cold air is thus given an opportunity to expand while it is being heated by contact with the hot tiles and upon commingling with the volatile gases entering the air-space F supply oxygen to produce complete combustion of said volatile gases, and the mixed air and gases in this highly-heated state, almost in the form of a flame, are admitted into the exit-flue L. Of course there are products of combustion resulting from the burning fuel 111 the lower part of the firechamber which also pass into the fiue L; but these serve to intensify the heat of the commingled air and volatile gases. Thus in addition to forming a conduit for such products of combustion as may be received thereby the chamber F also forms an effective mixingchamber for the volatile products from the fuel and the fresh air to support combustion thereof entering through the opening is.

In operation after the furnace is started coal is introduced into the reservoir, preferably filling the same, and if it is desired to obtain a hot fire on the grate the ash-pit door is opened, so as to permit of a strong draft upwardly through the fire-chamber and into the flue. After the fire is well under way the draft through the ash-pit door is partially shut off and the opening 71:, made available, which results in admitting fresh air into the mixing-chamber. As the direct draft is not above the line of the openings in, it follows that the burning fuel will be confined in the fire-chamber below said openings, and as said fuel is exhausted and turned to ashes the green fuel in the reservoir above falls by gravity, so that the fire-chamber is kept well supplied at all times.

I have spoken of the burning fuel being below the line of the openings is. I will state, however, that the radiated heat from this burning fuel evaporates the volatile gases from the green fuel immediately above the line of openings 7c, and in the event that the cover is closed, which cover is preferably airtight, these volatile gases will when they have an opportunity escape through the open ings k in a highly-heated state and then be commingled with the heated air which has entered through the opening Z3. I prefer in some operations of the furnace to leave the cover before referred to tilted, so as to admit a small quantity of air .on top of the bed of green fuel in the reservoir. Of course a large quantity of this air will ascend through the fire-chamber and create a draft which will carry with it the volatile products from the fuel, causing them to pass through the openings 1;. Part of the air entering from above will pass through the grooves h and into the chamberf and then down through the grooves e. In this manner a small quantity of fresh air is admitted to the ash-pit to support combustion in the fire-chamber. This air also tends to cool the shell Aand the outer faces of the tiling.

By the above operation it will be noticed that, due to radiated heat, the volatile gases are driven off from the green fuel above the line of openings it" and that said fuel becomes coked; that in this state it is in the best condition for combustion and will descend, when an opportunity presents itself, to a position below the line of openings in, where it is capable of being burned, complete combustion thereof resulting; that the furnace in normal operation is seldom run with a full updraft through the fire-chamber, (on the contrary, the draft is around the fire-chamber in the airspace F, and consequently is only able to support combustion of that material opposite the openings k;) that the radiated heat in coking the green fuel and driving off volatile gases forces said volatile gases which are in close proximity to the openings L" to at least contact with incandescent fuel, so as to burn the free carbon, and that the air to support combustion of the volatile gases while admitted at a low temperature is heated before being commingled with said Volatile gases and when commingled said gases are thus in the best condition to effect complete combustion of said gases the instant that the gases and commingled air are permitted to expand for the purpose of combustion. The small amount of products of combustion resulting from the burning of the coked fuel in the lower part of the fire-chamber passes with the commingled air and volatile gases in a highlyheated state into and through the exit-flue L, which exit-flue leads into the heating apparatus.

The fuel is completely consumed in my improved furnace, free carbon in the products of combustion being absent and a very small quantity of ashes falling into the ash-pit; but with respect to this a more important point is the entire absence of clinker and unburned coal or coke in the ash-pit.

The tiles about the lire-pot and the green fuel in the reservoir above the same are poor conductors of heat and prevent radiation of heat from the furnace proper. Should any heat radiate from the tiles, however, it is taken up by the incoming air flowing downwardly through the passages it, f, and a and is returned to the fire-pot, whereby the shell of the furnace proper is kept cool and the heat in the lire-pot is augmented. The prod nets of combustion and allof the heated air are conducted from the furnace-proper through the flue L to the heating-drum.

The heating apparatus (shown in Figs. 5 and 6) consists, preferably, of a cylindrical mantle N, into the bottom of which leads a cold-air duct 72., while from the upper portion lead hot-air pipes 02/, said pipes going to the various rooms or apartments to be heated. In this shell or mantle is arranged a casing 0, preferably cylindrical, which casing is mounted on a suitable base 0. A flange-ring p is secured to the upper end of easing O and to an inner cylinder P, which cylinder is supported at its lower end upon the casting 0. The flue L, before referred to, passes through an opening in the mantle N and enters the space between the cylinders O and P, discharging the gases passing therethrough into said. space. In order to prevent these hot gases from impinging against the cylinder P and also for the purpose of directing said gases upwardly into the space between the cylinders O and P. I arrange a deflecting-hood Q, preferably made of fire clay, on the inner end of the flue L, said hood being supported by suitable brackets secured to either of the cylinders O or P and discharging gases received by it from the flue L in an upward direction. The tendency of these heated gases is to rise in the space between the cylinders O and P. Finding no exit at the top, as they become cool or as they are induced by a draft they descend into the base 0, which base is provided with a number of ways or conduits 0, leading to a central chamber, from which rises a cylindrical stack R. This enter the space between the cylinders O and P they are directed upwardly, and immediately that they issue from the hooded deflector they are permitted. to expand and spread in said space. The products of combustion descend when they become cool or when induced to descend by the chimney draft to the passages 0,whence they enter the stack R and pass therethrough and the small pipe r into the chimney. The cold air to be heated entering pipe 11 may pass upwardly either between the cylinder 0 and the mantle or between the cylinder P and the stack R. In any event it is heated, and when it reaches the upper portion of the mantel it is conducted by pipes a to the rooms or apartments to be heated. I will state that an apparatus constructed as above described has been in use by me for heating a ten-room house. The fuel used was soft or bituminous coal, and during the six months time in which the furnace was in op eration about fifteen to eighteen tons of bituminous coal were used in my furnace as compared with a corresponding number of tons of hard or anthracite coal which would have been required to heat the same house if an ordinary upright furnace, such as ordinarily employed, had been used.

From the above it will be seen that the furnace being arranged in close proximity to the heating apparatus enables the heat generated in the furnace and in the heating-drum in the event that the volatile gases burn in the drum to be directly taken advantage of, the air absorbing said heat readily from the expansive surface of the drum. It will also be noted in this regard that the heating-d rum instead of being pierced by a single air-duct, as the cylinder P, can have a plurality of ducts or pipes through which the air can pass.

\Vith regard to the furnace it will be seen that the green fuel in the top of the reservoir is kept 0001 until it has descended some distance down into the coking-chamber formed by the tiles (1i. These tiles G form a tapering coking-chamber largest at its lower end, so that when the heavy hydrocarbon gases exude from the fuel being coked, which gases or semiliquid ingredient will tend to cake the fuel, the divergent walls of the chamber facilitate the descent of the fuel and prevent the chan1- her from becoming choked. Of course it is desirable to keep the reservoir filled with fuel at all times and, as has been just above stated, the fuel has been kept cool in the reservoir and in its natural state until it is received by the coking-chamber. In practice a full reservoir should supply fuel to the furnace for twentyfour hours without renewing the fuel. The thickness of the lower portions of the tiles E opposite the lire-chamber prevents any amount of heat from radiating from the furnace proper, and the presence of the grooves in the outer faces of these tiles also permits the air to absorb some of this heat and keep it in the furnace.

It is highly desirable in my present invention that the furnace shall generate heat to drive oh the volatile gases, so that not only the fuel, but the gases thereof, shall be completely consumed and that as high a percentage of heat units generated by the fuel be delivered into the heating-drum as is possible. To this end the eXit-flueL is preferably made of fire-clay having thick walls, so as to prevent the radiation of heat, and, if desired, can be covered with an asbestos covering or surrounded by an inclosing shell forming a deadair space, which expedients are common in the art.

I am aware of the existence of magazine heating-stoves in which fuel is placed in a reservoir or chamber in the top of the stove; also, that heating-drums have been" employed around stovepipes to increase the area of heating-surface, and so heat the air in a room or apartment. Therefore I do not broadly claim the combination of self-feeding combustionchamber and a heating-chamber, except in so far as said heating-chamber, closely connected, is made the recipient of total initial heat of fuel consumed and its housing or mantle is apart from the combustion-chamber, thus requiring a flue to pass products of combustion through the mantle into the heating-drum.

It will be apparent that the present construction presents many material advantages over apparatus in which heat is radiated from the furnace proper in to amantle or heating-drum. he furnace proper is not complicated by an encircling mantle, but can be constructed with reference to its use as a combustion apparatus only, thus making it possible to build the furnace proper in such manner that it produces perfect combustion in the simplest form. All of the heat units are held in the furnace proper until transmitted to the heating-drum through the flue L. Abundant grate-surface is provided, and the furnace includes a large magazine which is fed from the top. The heating-drum presents an unusually large radiating-surface in small compass and is of cheap construction, involving no intricate parts, but few joints and fittings, and no parts liable to burn out or clog with ashes or soot. Furthermore, the present apparatus avoids all liability of gases from the combustion-chamber getting into the space for the air to be heated.

I am also aware that many minor changes in the arrangement, construction, and combination of the several parts of my device can be made and substituted for those herein shown and described without in the least departing from the nature and principle of my invention.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

1. In a furnace, a shell, and a fire-chamber eccentrically arranged therein, there being an air-opening into the narrower portion of the space between said shell and the wall of said fire-chamber, an opening leading from said fire-chamber to the broader portion of said space, and an exit-flue leading from said broader portion of said space; substantially as described.

2. In a furnace, the combination with the shell, of a lining for the fire-chamber, and tiling arranged above said fire-chamber and forming an encircling air-space of graduallyincreasing area toward. the escape-flue; substantially as described.

3. In a furnace, the combination with the shell, of a lining for the fire-chamber, tiling arranged above said fire-chamber and forming an encircling air-space which communicates at various points with the upper portion of the fire-chamber, an escape-flue leading from said air-space, and an opening for admitting fresh air into said air-space; substantially as described.

4. In a furnace, the combination with the tiling forming the fire-chamber, and a mixingchamber, the lower portion of which mixingchamber communicates with the upper portion of the fire-chamber, and an escape-flue leading from the mixing-chamber and opposite one of the communicating openings between the mixing and fire chambers; substantially as described.

5. In a furnace, the combination with the tiling forming the fire-chamber, of tiling arranged thereabove and forming a passage for the supply of fuel from a reservoir, said lastmentioned tiling also forming a mixing-chamber; substantially as described.

6. In afurnace,the combination Withashell, of tiling lining said shell and forming a firechamber, tiling supported upon said first-mentioned tiling and spaced from said shell, and tiling spanning the space between said secondmentioned tiling and said shell, whereby a chamber is formed between said various tilings and the said shell, said first-mentioned and said last-mentioned tilings having grooves in their faces adjacent said shell for the circulation of air; substantially as described.

7. In a furnace, the combination with the shell, of tiling E, G and H forming the firechamber, an air-space which communicates at its lower portion with the upper portion of the fire-chamber, an opening Ir; leading into the upper portion of the front of said airspace, and an escape-flue leading from the back of said air-space; substantially as described.

8. In a furnace,the combination with a shell, of tiles having their inner, upper portions cut away to produce a shoulder, tiles supported upon said shoulder and spaced from the remaining upper, outer portions of said firstmentioned tiles, and tiles spanning the space between and supported upon the upper ends of said before-mentioned respective tiles; substantially as described.

9. In a furnace, the combination with a shell having an ash-pit at its lower portion, and a reservoir at its upper portion, of a fire-chamber above the ash-pit, tiling for forming a mixing-chamber F, which mixing-chamber communicates with the fire-chamber at different points, a flue leading from the mixingchamber for conducting off the products of combustion from the fire-chamber and also the commingled air and volatile gases from the mixing-chamber, an opening leading from the exterior into the mixing-chamber at a point opposite the exit-flue, the reservoir above the fire-chamber constantly supplying fuel thereto, and ducts or passages from said reservoir to the ash-pit beneath the fire-chamber; substantially as described.

10. The combination with a furnace of the character described and its escape-flue, of a drum consisting of the cylinders O and P, said escape-flue leading into the space between said cylinders, a hood for deflecting gases passing through the escape flue upwardly in said space between said cylinders, and an axiallyarranged stack communicating at its lower end with the lower portion of the space be tween the cylinders O and P; substantially as described.

11. The combination with a furnace of the character described and its escape-flue, of a cylinder O through which said escape-flue passes, a deflecting-hood on the end of said escape-flue, a cylinder P, a base-casting upon which said cylinders are mounted, said basecasting being provided with radial passages, and a centrally-arranged stack for conducting off the products of combustion entering thereinto from said radially arranged passages; substantially as described.

12. The combination with a shell having a reservoir at its upper end and an ash-pit at its lower end, of a lire-chamber, inclined tiles G forming a tapering coking-chamber which connects a reservoir and the [ire chamber, said tiles also forming, in part, an encircling mixing-chamber, and openings leading from the junction of the coking and lire chambers into said mixing-chamber; substantially as described.

13. In a furnace, a fire-pot lining having formed therein a chamber for receiving the heated gas and products of combustion, said chamber surrounding the fire-pot space, openings leading through the wall of said lining from the lire-pot to said chamber, and an escape-flue from said chamber; substantially as described.

14. In a furnace, a lire-pot, a surrounding chamber for receiving the heated gases and products of combustion, an escape-flue leading from said chamber, and air-passages extending substantially entirely about said fire-pot and substantially the whole length thereof and having one end open to atmosphere and the other end leading into said fire-pot to supply air thereto; substantially as described.

15. In a furnace, a fire-pot with an inclosing wall of material which is a poor eonductor of heat, a magazine above said 'lire-pot, whereby fuel in said magazine can form substantially a continuation of the said wall for the purpose of preventing escape of heat from said fire-pot, and a flue for the escape of heat; substantially as described.

16. In a furnace, a fire-pot having a wall about the same, and draft-passages outside of said wall at the exterior of the furnace, said passages extending substantially entirely about the furnace for returning escaping heat; substantially as described.

17. In a furnace, a fire-pot having a wall of material which is a poor conductor of heat, and an air-passage outside of said wall at the exterior of the furnace, said passages extending substantially entirely about the furnace for returning escaping heat; substantially as described.

18. In a furnace, a fire-pot having a wall about the same and provided with a bottom opening for ingress of air, and a draft-passage outside of said wall and leading to said bottom opening, said draft-passage being open to the atmosphere at its top; substantially as described.

19. In a furnace, a chamber for the production of heat, and air-passages outside of said chamber and extending substantially the whole length thereof, said passages having one end open to the atmosphere and the other end in communication with said chamber, whereby escaping heat is returned to the furnace; substantially as described.

20. In a furnace, a fire-pot, a separate magazine supported thereon, and a mantle surrounding said parts and spaced therefrom to produce an air-space; substantially as described.

21. In afurnace, a firepot, aseparate magazine supported upon said fire-pot, and a mantle aboutsaid parts, there being an air-space between said parts and said mantle and having one end leading to atmosphere and its other end leading to said lire-pot; substantially as described.

22. In a furnace, a fire-pot, an inclosing mantle therefor and having an opening to atmosphere, and an airspace between said mantle and fire-pot, one end of said space leading to said lire-pot and the other end thereof communicating with said opening; substantially as described.

23. In a furnace, a lire-pot, an inclosing mantle therefor and having an opening to atleading to said fire-pot and theother end mosphere, an air-space between said mantle thereof communicating with said opening; and fire-pot, one end of said space leading to substantially as described. said fire-pot and the other end thereof com- In testimony whereof I hereunto affiX my I5 5 municating with said opening, and a closure signature, in the presence of two witnesses,

for said opening;substantially as described. this 5th day of June, 1901.

24. In a furnace, a fire-pot, a magazine, a

mantle inclosing said fire-pot and having an PRESTON BRUNER" opening to atmosphere which forms a feed WVitnesses:

-for said magazine, and an air-space between V GEORGE BAKEWELL,

said mantle and fire-pot, one end of said space ANNA S. GRAY.

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