US673434A - Hot-air furnace. - Google Patents

Description

No. 673,434. y Patentdy May 7, 190|.

J. W. HURNSEY, Wn. E. ELLENBERGER S. M. DUTY H01' AIR FUBNACE. (Application led Nov. 8, 1899. Renewed 011.5, 1900.\ i (No Model.) 9 Sheets-Shoe; l.A

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No. 673,434. Patented may 7, 190|. .1. w. Honusev, w. E. ELLENBERGER & s. m. nuTv. HOT AIB FURNACE.

(Application filed N ov. 8, 1899. Renewed 0er-4 5, IQQO.)

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HOT AIB FURNACE.

(Application tiled Nov. 8, 1899, Renewed Oct. 5, 1900.) (No Model.)

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J; W. HORNSEY, W. E. EL'LENBERGER &. S. M. DUTY.

HUT AIR FURNACE.

(Application filed Nov. 8, 1899.` enewed Oct. 5, 1900.)

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MOT AIR FURNACE.

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No. 673,434. i A v Patented May 7, |9 0I. A

J. W. HORNSEY, W. E. ELLE'NBERGER &. S. M. DUTY. HOT AIR FURNACE.

(Application led Nov. 8, 1899. -Renewed Oct.. 5, 1900.)

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HOT AIB FURNACE.

(Application led Nov. 8, 1899. Renewed Oct. 5, 1900.)

(No Model.) 9 Sheets-Sheet 7.

No. 673,434 Patented May 7, lam. J; w.' nonnsev, w. E. ELLENBERGER & s. M. DUTY.

HOT AIR FUBNCE;

(Application led Nov. 8, 1899. Renewed Oct.' 5, 1900.)

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lo. 673,434. Y Patnted May 7, |901. v

J. W. HORNSEY, W. E. ELLENBERGERYGL S, M. DUTY.

HUT-AIR FUBNACE. I

(Application led Nov.*8, 1899. Renewed Oct. 5, 10ML-y (No Model.) 9 Sheets-Sheet 9.

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UNITED STATES APATENT OFFICE.

JOHN W. HORNSEY, WALTER E. ELLENBERGER, AND SPENCER M. DUTY, OF CLEVELAND, OHIO, ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE CROVN DRYER COMPANY, OF SAME PLACE.

HOT-AlR-,FU RNACE.

SPECIFICATION forifning-` part of Letters Patent N 0. 673,434, datd May 7, 1901.

Application filed November 8, 1899. Renewed October 5, 1900. Serial No. 32,187. (No model.)

To all whom it may concern:

Be it known that we, JOHN W. HORNSEY, WALTER E. ELLENBERGER, and SPENCER M. DUTY, citizens of the United States, residing at Cleveland, in the county of Cuyahoga, and State of Ohio, have invented certain new and useful Improvements in Hot-Air Furnaces, of which the following is a specification.

For heating air for drying brick and other materials and for heating buildings and for other purposes we have produced a structure whereby the air is heated in one or more comparatively thin Volumes within flues surv rounded by tire products and at a higher temperature than can be effected by the ordinary system of radiation and by which practically all the heat units of 'the fuel are rendered effective on air flowing in extended separate and distinct thin layers in contact with the fire-due walls. For certain purposes it is highly important to produce pure air heated to a very high degree, and for this purpose the structure should be of material which will withstand without injury the intense heat and to secure the best results from the combustion of the fuel, which can only be secured under very high temperatures.

Our improvement involves a diffusion of hot air and lire products in separate and distinct contiguous courses at right angles to each other, whereby air in a multiple of eX- tended layers is caused to flow in contact with intensely-healed walls passing through the dues which confine the air-layers.

'l`h'e following description, read in connection with the accompanying drawings, will enable any one skilled in the art to which our improvement relates to understand its nature and to practice it in the form which we prefer to employ it. an air-heating structure adapted for carrying into effect our method of diffusing the heat products from a furnace and utilizing them to heat air in a multiple of thin ex-V tended bodies, as we will now proceed to describe.

Figure l shows in vertical section the structure wherein the heat is extracted in its relation to the furnace and intermediate provi- These drawings illustrate sions whereby the lire products are commingled, diused, and directed, the section being taken on the line C D of Fig; 2 and showing the fire products entering and passing downward through one section of the heat-extractor Hue. Fig. 2 shows in horizontal section, taken on the lineA B of Fig. 1, the relations of the two divisions or sections of the flue heat-extractor and the connection of the furnace therewith and particularly illustrating the disposition of the walls separating the air-passages from the fire, at which point the heated airis deliv- -which the fire products ascend to the stack.

Eig. 5 is a horizontal section taken on the line M N of Fig. 3, particularly showing the 'foundation and base-flues connecting the two Elue-divisions of the heat-extractor. Fig. 6 shows a vertical section on the line O P of Fig. 5, illust-rating the arching of the -mediate diffusion base-fine connecting the two divisions of the heat-extractor. Fig. 7 is a horizontal section on the line 2 2 of Fig. 3, illustrating in top View the two [lue wall, the top heat-diffusion chamber, and the vertical flue connecting it with the furnace, the oblique base-dues being seen in dotted lines. Fig. 8 'shows in elevation the wall having the openings for the ad mission of the air into the flue heat-extracting structure. Fig. 9 shows in perspective a group of the slabs forming the aix-passages and lire-fines of two tiers and an intervening flue-space for the heat to illustrate more particularly the method of delivering the fire and the air and the direction 'at right angles they take through their respective lues and passages. Eig. l0 shows a like View of the horizontal heat-extracting sections and their dividingire-ue space and the blocks at the corners of the descending fire-fines, the direct-ion of the fire and air being indicated lby the arrows, especially the fire products in the fluespace. Fig. 11 shows a tier of horizontal airpassages and fire-dues uncovered and the direction of the fire and air by the arrows. Fig. 12 shows in plan View a slab in whicgh the vertical lire-line openings are made; and Fig. 13 is a vertical section of a slab, showing the recess and shouldered seating with the vertical fre-flues in place.

The course of the fire products is indicated by the arrows 21, and the course of the air is indicated by the arrows 22.

The structure has the character of a kiln, such as is used for the burning of brick and similar materials, and is constructed Within suitable closure-forming walls 1 in communication with a suitable furnace 2 and stack 3 or fan for theproduction of the required draft.

In the design shown the products of combustion from the furnace enter the flue structure at the top bya suitable vertical fire-flue 4, which communicates with the furnace through a mixing-wall 5 at one of the vertical sides of the structure; but our invention comprehends any other arrangement of dues or direction of products from the furnace.

ln the construction shown the heat-extracting structure is of two distinct and separate flue sections or bodies side by side and organized for a continuous draftv for the products of combustion passing through the flues of one into and through the fines of the other, preferably as shown at the top `of the initial flue-section into the bottom of' the connecting flue-section, while the air inA large volumes enters and passes through .horizontal passages 6, surrounding the walls 23 24 of the heat connecting-dues 7 in a way to lbring the air in contact with the largest heatlradiating surface. Preferably, as shown, the; course of the air in being heated is substantially at right angles to the course of the products of combustion. While the air in its course accumulates heat in a large volume within the horizontal passages 6 of the structure, it is introduced therein through aperturesl18 in that vertical wall of the structure which is opposite to the exits 9 of said passages 6 in such manner that the walls of the air-passages1 are surrounded by the fire-lines 7, provided for lthe products of combustion, the said passages and flues being formed by the vertical and horizontal slabs, which in separate tiers are supported by the corner-blocks 20.

Upon a suitable foundation 10 the separate flue-sections of the structure are reared and have at their base separate flues 11 in cornmunication with the furnace and with each other through the arched heat-dilfusion due 12. For distinguishing the flue-sections of this structure we will call the initial section No. 1 and the connecting-section No. 2, and while only two flue-sections are shown it is obvious that the number may be increased, each having substantially the same system of heat and air ues, or a simple section may be used. Section No. 1 has in its bed vertical re-flues 11, which open into a base draft-flue 12 beneath the mediate wall, and upon the walls 13, which form these iues and which separate the latter, are built up other walls by bricks or slabs 23 24 and corner-blocks 20,

forming and separating fire and air lines from the bed to the top. (See Fig. 5.) These walls arebuilt in horizontal tiers or layers supported so as to form intervening spaces 14, Figs. 4 and V10, connecting the fire-lines of the respective tiers and at the same time separating the air-lines. In this construction the lire-flueslare vertical, open at the top of duesection No. 1 in communication with the furnace and'at the bottom through the baseiiues 11 with section No. 2 through the mediate base-Hue 12, while the air-dues are horizontal and passing through both sections open through the outer wall, as in Figs. 2 and 3. The mediate wall forms the inside wall of a top diffusion-chamber 16, and the inside Wall of the chamber above section No. 2 leading into the smokestack, as in Fig. 3. ln this figure is also seen an important feature of novelty in the mediate wall in its relation to the two sections andthe tiers of flues thereof, wherein is disclosed ythe manner in which the base communicationlis made between the two sections and also the manner in which the air-dues are built up`with said wall so as to project from each side of the wall into the respective ascending anddescending linesections, and which will be more particularly presently described in connection with section No. 2. Within the space between the mediate and the air-exit walls of section No. l is built the vertical flue 4, preferably of semicylindrical form, joining the furnaceconnecting walls forming the inlet fire-due from the furnace and opening at its top into the arched diffusion-chamber 16, which incloses and directs the fire into the upper openings of all the fire-flues of section No. 1.

The arched heat-diffusion chamber opening into a series of down .fire-dues and the vertical flue 4 opening into the combustion-chamber 17 of the furnace 2 by means of a checkered wall 5 gives the advantage of delivering the products of combustion in a perfectlycommingled condition into section No. l, and it is by this diffusion in the arched chamber 16 that the maximum heat is produced.

An important advantage due to the con- .centration of the maximum degree of heat at a point over the section No. 1 is that such location practically isolates the heat-diffusion chamber and 'carries it away from any point of the furnace Where cold air is admitted. This advantage is also enhanced by the interposition of the vertical flue 4, the commingling-walls 5 and 18, and combustion-chamber 17. between the grate bars and diffusionchamber, and it is this isolation which main- IGI) tains the intensity of the heat at thev very point where it is most needed. In thus concentrating and maintaining the maximum heat at the point where the gases of combustion and air are most completely mixed insures the most thorough combustion with the resultant economy. The provision of this diffusion-chamber in effecting the results stated becomes an essential factorin the accomplishment of the most complete combustion of the heat-producing elements'in immediate proximity to the entrance of the re-ues of section No. 1, and it is at this point we obtain Vthe full effect of the most intense heat upon the radiating-surfaces, and it is from this side of the structure that the air after having passed through the entire structure makes its exit for heating or drying purposes.

Referring to Figs. 1 and 2, it will be seen that the wall of the vertical flue 4 forms the wall ot' the adjacent air-,dues 6 and which by such construction are enlarged around t'he wall of this lire-flue. This enlargement of the air-flues gives the advantage of allowing an enlarged volume of air to follow around the wall of this flue, thus absorbin-g the larger amount of heat radiated by this wall. This fine-wall is built'up with and forms part of the section-tiers, while the other walll of this iiue is formed by the mixing-wall and the closure-wall above the latter. The structuresection No. 2 is formed on the other side of the mediate wall and between it and the closure-forming wall, and the air-passages of both sections are made continuous by openings 19, Fig. 2, in the-mediate wall,while the` fire-fines are made continuous and to connect with both sections through the base and mediate iiues 11 and 12. The two sections as to their re and air lines are of identical construction, and it will be understood that the' the mediate wall, through section No. 1, and

finally out at corresponding openings 9 in the exit-wall. In section No. l the mediate wall forms the walls of the joining freflues',while the outer closure-forming wall forms the wall of the contiguous tire-flues. As seen in Figs.

3 and 10, this section shows the air-fiues so=y arranged as to divert the course of the Ire from the outer and the inner hues horizontally into the space 14, formed between theI tiers. This space extends on aplane the full area of the section, and into it all the fireiiues open from the next above tier, andi through this broad area all the fire-dues opening into it are caused to communicate one with the other and with the ues of the tier below, so that, as seen in these figures, the Iire m ust pass from the diusion-chamber down in a zigzag course into the base-fine 11 and in sov It will be doing m ust surround the air-lines. noted that the walls of they horizontal flue- 'fuel. sult the air entering section No. 2 at the top i wall-openings comes in contact with the coolv leaves said section.

tiers are supported one upon the other by small blocks 20 of re resisting material, forming intervening horizontal shallow spaces 14, into which the vertical fire-fines open, while upon the bottom of said space the ire productsin their downward course strike and are diverted through the spaces into the descending Iiues of the tiers below. In this di- Version of the fire the volume is crowded in a way to retard its passage and to force it out from the space in all directions. This same crowding and diversion of the tire volume is repeated in the space between each tier and produces a continuous commingling of the combustible gases in their downward passage. This same result is effected by an identical construction and arrangement of the lues and spaces in section No.2, so that there is a contin nous zigzag course oi the fire products from the top of section No. 1, descending through said section through the base-flues into and ascending through section No. 2.

Referring to Fig.. 4, the air and fire [iues are those of section No. 2, the arrangement and construction of which is-identical with that of section No. 1, (shown in Fig. 1,) in

which, however', the course of the fire products is upward to the stack.

Referring to Fig. 2 is seen the zigzag course of the air in its passage in a horizontal direction only through the tlues of each and every 'tier in the sections.

Looking at the lues and their ramifications -in the several ligures noted, it will be seen 'that we have accomplished a surrounding of the air-Hue walls by re products .at every point of their passage through the heat-extractor, and to the same extent and under the same conditions we have surrounded the walls lof the fire-fines by the air to be heated, and

it is evident that'loy so doing we accomplish vthe vital matter of extracting practically all the heat from the products of combustion, so that while the fire products enter section No. 1 at a very high heat they leave section No. 2 ata comparatively low heat and have parted largely with the combustible matter of the In the attainment of YthisA important reest part of the heat-extractor, and which is that part at which the heat leaves, it and passing through the mediate wall enters section No. l at its highest portion, which is the point at which the fire enters. Taking section No. 2 at its lowest air-flue, the air entering at that point comes in contact with that portion of section No. 2 having the greatest heat, which is the point at which the ire enters said section, and passing through the mediate wall enters section No. 1 at its point of lowest temperature,which is the point at which the fire By this method of heating the air it is delivered from the extractor at a temperature which is uniform at the varying heights of the exit-openings. By this` method our invention is capable of produc- IOO ing pure air heated to a temperature very much higher than can be obtained by steamheating or metallic radiators, which in any case can rarely exceed two hundred and fty degrees, whereas by our method air may be heated to two thousand degrees. Looking at the base-iiues in Fig. 5, their oblique arrangement is made to render the foundation more solid, and because the vertical iiue 4 projects into and shortens section No. 1 and by the connection of these Ilues 11 with the base draft-flue 12 We secure an equal distribution of the fire products as they enter section No. 2.

At various parts of the furnace and heatextractor access is had for cleaning and repairs by doors.

In Fig. 2 it is seen that all the air-fines deliver heated air into a chamber common to all, from which it may be conveyed to the point Where it is utilized for any desired purpose. In Figs. 9, 10, and 11 is better seen the relative arrangement of the air and fire flues and the horizontal space between each tier and the spreading of the lire products in all directions as they leave the vertical flues and enter this horizontal space, and particularly through the passages between the blocks in directions at right angles. l

In the drawings the lines are shown as built up of comparatively small matching brick or parts; but in practice the surfaces forming the top and bottom of the horizontal fire spaces we prefer to make of slabs the entire area of the sections and having flue-openings. In this construction the line-openings will be surrounded by a surface recess and the ends of the vertical fire-lines seated into the recesses. The importance of this construction is that it very greatly lessens the number of pieces and necessarily the number of joints in assembling the parts. The vertical fire-dues may also be made with their four walls in one piece.

In Fig. 7 the fireresisting walls of the heatextractor are distinguished from the closureforming Walls proper, and this construction gives the advantage of separate surrounding walls for the separate heat-extractors and in this way provides for the varying expansion incident to the difference in the temperature of the two sections and also incident to the diiference in the heat of the two walls.

Referring to Fig. 8, it is obvious that a greater or less number of air-dues may be used, and the tiers of fire-dues must correspond. Bricks may be used set in the entrance of these ues to regulate their area, and thereby the volu me of air admitted. This regulating provision gives the advantage of cutting out from the heat-extractor one or more iues of each tier or of diminishing the inlet area of one or more of all the air-fines, and this may be done by a separate slidevalve for each opening or by a slide-valve for a tier of openings. The advantage of this regulation is that air admitted in smaller volumes can be heated to a higher temperature, and this gives the attendant absolute control of the temperature of the air at the point of delivery to suit the requirement. In this ligure the upper tier of air-inlet openings Sis seen provided with slides 25, confined between guideways, so that the slides can be set to close or partially close the openings, as may be found necessary for the purpose stated.

In Figs. 1 and 3 a multiple of fire-dues 7 receive the lire products from the diusionchamber and deliver them into the baseeues 11 on one side of the mediate Wall, and the walls of these fire-dues are seen as forming and inclosing the air-passages 6, each layer of the flue-walls being separated by a horizontal space 14, into which the fire products spread laterally as they descend in a staggered course from one space to another. From the base-dues of the flue-section No. 1 the heat products pass intothe base draft-line l2, and from thence into the base-fines 1l of the fluesection No. 2, into and through the fire-fines 6 of which the fire products pass upward to the draftstack, and in such course its heat units are given to the air by radiation.

In Fig. 2 the horizontal air-passage of one of the tiers is seen as extending over the full area of the two nue-sections, with inlet and outlet openings corresponding to the number' of` the passages 6 formed by the flue-walls, and this passage is as deep as the flues 6 (seen in Figs. l and 3) and gives free diusion for the air around the walls, which attain great heat from the fire-flues. The ad mission of air in a multiple of thin volumes in contact with the walls, which to a greater or less eX- tent are caused to have a red heat, and the delivery of the hot air from the passage in a multiple of volumes aids in obtaining to the fullest advantage the radiated heat from the lire-fines.

Referring to Figs. 9, l0, and 11, it will be seen that the air-passages and the iire-iues are formed by the same walls, the bricks or slabs 23 being vertical and connected at their ends by horizontal bricks or slabs 24, which are separated by the corner-blocks 20.

In the construction and arrangement shown the air-passages are formed by adjacent surfaces and the re-flues by the adjacent other surfaces of the same Walls, and when any one of the air-passages is closed at its inlet-opening such passage becomes a dead space in the due structure.

We claim- 1. In combination vin a furnace for heating air by radiation including the furnace, a walled closure in communication therewith,

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a mediate wall dividing said closure vertipassage having a multiple of inlet-openings in the outer wall of said closure and amultiple of exit-openings in the opposite closurewall, the slabs inclosing and forming in separate parallel rows the vertical fire-fines having communication with the vertical draftiiue and with the draft-stack, and the airpassages and the fire-fines staggered as set forth.

2. In combination in a furnace for heating air by radiation including a furnace, a draftstack and a walled closure of flue structures side by side within said closure, each flue structure constructed of vertical and horizontal walls disposed in tiers to form horizontal passages for separate air volumes, each air-passagehaving a multiple of inlet-openings in the outer wall of said closure and a multiple of exit-openings in the opposite closure-wall, the walls of each air-passage forining also vertical fire-fines, a mediate wall dividing said flue structures into diving and ascending flue-sections and a vertical draft-flue connecting the diving-flue-section with the furnace.

3. In combination in a furnace for heating air by radiation including a furnace, a draftstaok and a walled closure, of a heat-extractor comprising a flue structure within said closure constructed of nre-brick or slabs built up in layers and arranged to form air-passages in separate horizontal ,tiers and vertical fire-fines arranged in parallel rows transversely of the air-passages,the latter arranged in tiers and `having in each tier a multiple of airinlet and exit openings in the opposite closure-walls, each fire-fine opening at the top tier, the walls of the air-passage forming also the walls of the fire-lines, a heat-diffusion chamber above the top tier, a vertical draftflue connecting said chamber with the furnace and a bottom draft-fine into which the fire-dues terminate and have communication with the draft-stack.

4. In combination in a furnace for heating air by radiation, a walled closure, a mediate wall dividing it, a top heat-diffusion chamber on one side of said mediate wall, and a vertical draft-tlue connecting the furnace and said top chamber, a horizontal base draft-flue, a flue structure within the closure between the top diffusion-chamber and the base draftflue, built up of ire-brick or slabs forming tiers of horizontal air-passages and vertical fire-fines arranged in parallel transverse rows, each fire-flue opening into the top diusionchamber and into the b ottom draft-due, the layers of brick which form the horizontal airpassages separated by corner-blocks and the said passages enlarged around in contact with the wall of the vertical draft-flue, and a draftstack in communication with the fire-ues.

5. In a furnace for heating air by radiation and in combination with the furnace, a draftstack, a walled closure having a top heatdiusion chamber in communication with the furnace, and a base draft-Hue in communication with the draft-stack, of a {iue structure between the top diusion-chamber and the base-Hue constructed of fire-brick or slabs in separate layers upon the walls of the baseiue and forming parallel rows of vertical fireiiues opening into the top diffusion-chamber and into the base-flue, the flues of one row in staggered relation to the flues ofthe adjacent rows, the layers of slabs forming such fire-lines separated to form horizontal airpassages arranged in tiers, each air-passage surrounding the walls of the fire-fines and having a multiple of inlet and exit air-openings in the opposite closure-walls.

6. In a furnace for heating air by radiation and in combination with the furnace, a draftstack, awalled closure having a top heatdiffusion chamber in communication with the furnace and a base draft-flue in communication with the draft-stack, of a flue structure between the heat-diffusion chamber and the base-flue, constructed of fire-brick or slabs in layers consisting of vertical and horizontal slabs arranged to form air-passages 6 in tiers, each air-passage extending the entire area of the iiue structure and having a multiple of inlet and exit air-openings in the opposite closure-walls, fire-dues 7 formed vertically within said tiers of air-passages, and horizontal fire-spaces let between the air-tiers into which the vertical re-iues open, in the successive tiers from the top heat-diffusion chamber to the base-flue.

7. In a furnace for heating air by radiation and in combination with a furnace, a draftstack, a walled closure having a lfop heatdi'usion chamber and a vertical draft-flue in communication with the top chamber and with the furnace, of a flue structure built upon the walls of said closure and of said draft-flue, extending above the furnace forming the bottom of the diffusion-chamber and constructed of fire-brick or slabs arranged in horizontal tiers and vertical parallel rows forming horizontal passages 6 and vertical fire-fines 7 14, the air-passages having inlet 'and outlet openings for each flue 6 in the opposite closure-walls, the fire-fines opening into the top heat-diffusion chamber and coinmunicating with the draft-stack, a mixingwall forming one side of the vertical draftflue and arranged between it and the furnace.

8. In a furnace for heating air by radiation and in combination with the furnace, a draftstack a walled closure having a top heat-diffusion chamberl a vertical draft-Hue in communication with said top chamber and with the furnace, a vertical mediate wall dividing said closure, and a draft-line 1.2 at the base of said closure, of a iiue structure on each side of said wall built upon the closure-Walls, extending above the furnace, and constructed of fire-resisting slabs 23 24 separated by corner-blocks 20, forming passages 6 arranged in horizontal tiers passing through the mediate wall and vertical fire-fines 7 14.- on each side of said wall, the base-fines 1l on each IIO IIS

side of the base draft-tine 12, both structures having air inlet and outlet openings in the opposite closure-walls, the diving iue structure having direct communicating with the furnace and the ascending flue structure having direct communication with the draftstack.

9. In combination in a furnace for heating air by radiation and including the furnace, a communicating walled closurea draft-stack, a heat-diffusion chamber at the topv of said closure and a Vertical draft-due connecting the top diffusion-chamber and furnace, of a iiue structure the top of which forms the bottom of the didusion-chamber and comprises bricks or slabs built up and arranged to form air-passages 6 in separate horizontal tiers and vertical fire-flues 7 111, in parallel rows, each tier of air-passages provided with amultiple of air-inlet openings and a multiple of outletopenings, a base draft-line l2 into which the fire-fines terminate, and means whereby any Ione or more of the tiers of air-passages may be closed to increase the heat of the flue structure or diminish the volume of vair to be heated.

10. In a furnace for heating air by radiation and in combination with the furnace and the draft-stack, of a heat-extractor comprising a walled closure, a flue structure therein constructed of fire-brick or slabs arranged in layers forming air-passages in separated horizontal tiers and vertical fire-fines arranged in parallel rows transversely of the airpassages, each fire-line passing between the tiers of air-passages, having air supply and exit openings arranged in series foreach separate passage, each fire-Hue opening at the top tier and terminating at the bottom tier, the airpassages being'staggered to deflect the air in the line of the draft and the fire-fines staggered in the line of draft to deflect the fire products as set forth,

11. In a furnace for heating air by radiation and in combination with the furnace, a walled closure in communication with the furnace, a vertical wall mediately dividing said closure, a diffusion-chamber above and on one side of the mediate Wall, a vertical draftue in communication with the diifusionchamber, a draft-stack on the other side of said mediate Wall anda base draft-flue, of a line structure comprising a diving section on one side of the mediate wall and an ascending section on the other side of said wall, the said flue-sections constructed in layers forming air-passages in separate horizontal tiers passing through the mediate wall and through both sections, and also forming vertical ire- {iues arranged in parallel rows passing between the walls of said tiers, each separate air-passage having a multiple of air inlet and outlet openings in the opposite closure-walls.

12. In a furnace for heating air by radiation and in combinationwith the furnace, a draft-stack, and walled closure, having a heat-dilusion chamber at the top of the closure, a Vertical draft-Hue connecting the top chamber and the furnace, with a iiue structure within said closure forming the bottom of the top chamber and a Wall of the draftflue and constructed with ire-ues arranged in vertical staggered rows opening into said top chamber and horizontal air-passages arranged in tiers, each passage having a multiple of air inlet and exit openings at opposite sides of the closure, and a base draft-flue in communication with the draft-stack.

In testimony whereof we afiix our signatures in presence of two witnesses.

JOHN W. HORNSEY. WALTER E. ELLENBERGER. SPENCER M. DUTY. Witnesses:

J. A. LIGHT, WILLIAM H. HILL.

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