US1986675A

US1986675A - Gas fired hot air furnace

Info

Publication number: US1986675A
Application number: US384553A
Authority: US
Inventors: Stanley H Hobson
Original assignee: Geo D Roper Corp
Current assignee: Geo D Roper Corp
Priority date: 1929-08-09
Filing date: 1929-08-09
Publication date: 1935-01-01
Anticipated expiration: 1952-01-01

Description

Jan. 1, 1935. s. H. HOBSON GAS FIRED HOT AIR FURNACE Original Filed Aug. 9, 1929 I5 Sheets-Sheet 1 1, s. H. HOBSON, 1,936,675

GAs'FIRED HOT AIR FURNACE Original Filed Aug. 9, 1929 3 Sheets-Sheet 2 3 1935- s. H. HOBSON 1,986,675

GAS FIRED HOT AIR FURNACE Original Filed Aug. 9, 1929 3 Sheets-Sheet 5 Fr M4. 6 T: a

" hot air furnace.

6 years, but were generally used only in those that the corrugations afford longitudinal chan- 0 This form of radiator sections, in addition to Patented Jan. 1, 1935 UNITED STATES PATENT oFFica GAS FIRED HOT AIR FURNACE Stanley H. Hobson, Rockford, 111., assignor to Geo.

D. Roper Corporation, Rockford, 11]., a corporation of Illinois Application August 9, 1929, Serial No. 384,553

Renewed May 16, 1934 40 Claims. (Cl. 126-116) This invention relates to an improved gas fired flow, in straight paths from the lower ends to the upper ends of the columns. In other words,

the special formation of the surface to obtain. increased area is not made at the sacrifice of unobstructed air passages. As evidence of the soundness of this principle of operation, itis to be noted that the efliciency of a furnace utilizing radiator sections of this description was found to be 72%, as compared with an efiiciency of or less secured with other gas fired furnaces with which I am familiar.

Among other features of the furnace of my invention which are also responsible for its aidcient operation, may be mentioned theprovision of large inlet openings for the columns of Furnaces of the kind referred to have been made in various designs for quite a number of localities where natural gas is available at low cost; their efliciency was admittedly very low and it was out of the question for a manufacturer of such furnaces to attempt to compete with manufacturers of other kinds of heating equipment on the basis of economy in operation in localities where only artificial gas is available. It is, therefore, the principal object of my invention to provide a-gas fired furnace of such improved design and construction that the products of combustion are so thoroughly and completely stratified and so' much area is presented to take up the heat therefrom and transfer it to the air, that the furnace operates economically enough, at least as compared with oil burners, to make the same practical and suitable for operation with artificial gas, there being the advantages with this kind .of furnace over oil burners that one does not have to have a storage tank that has to be refilled regularly, that there is practically no odor, vapors, or soot incident to the operation thereof, and no objectionable noise. More specifically stated, I provide a plurality of radiator sections extending from alower combustion manifold to an upper flue manifold, each of which has the columns thereof of flattened section so as to cause the products of combustion in passing therethrough to be spread out into as thin streams as possible, and thus make for the most efliclent heat exchange through the walls of the radiator sections with the air passing over the outside of the latter. In addition to this feature of spreading out the products of combustion into thin streams, which partly accounts for the good efficiency of operationof the furnace, I have found that by longitudinally corrugating the walls of the columns of the radiator sections, I secure still better efiiciency, because in that way the streams are further broken up into a multiplicity of separate streams, each of which flows through a separate, substantially tubular channel, so that the air to be heated has access thereto from all sides to abstract as much heat therefrom as possible.

floating at the burner by allowing easy take-off of the products ofcombustion, the outlets for said columns leading into the flue manifold being of smaller size so as not to permit of too rapid flow of the products of combustion through the columns, such as would be inconsistent with efiicient heat transfer to the air to be heated. It is also important to mention the baflles mounted in the outlet openings having different sized openings therein for the different radiator sections, with the idea of preventing faster flow of products through one section than through another, because of heavier draft effect at one point of the flue manifold than at'another, it being found that the draft is heaviest at the middle and lighter at the ends, so that the bailie openings should be larger for the end sections than for the middle sections to equalize the draft effect.

I have embodied various other advantageous features of construction in the furnace that make for economical production, ease in assembling and installing, and simplicity of control and regulation of the' operation, as well as general neatness in appearance, among which may be mentioned, in addition to the-sectional construction of the entire radiator unit, mentioned above, the provision of rigid front supporting legs for the radiator unit, in combination with "a movable rear supporting leg, the rocking of which permits the expansion and contraction of the unit in the operation of the furnace; the provision of adjusting screws on the feet of the supporting legs by means of which the radiator unit can be accurately leveled on an uneven basement floor for giving the desired increased surface area for eflicient operation of the burner; the provision of contact by the air to be heated, is of advantage in wall of which is formed mainly by a door, the closnels on the outside of the columns to conduct ing of which covers up all of the valves and pip-' streams of air, with minimum obstruction to ing to simulate a cabinet for neatness in appearthe radiator sections that serve to avoid danger of a double-walled front for the fum'ace the outer ply pipe through a float-controlled valve which serves to maintain a predetermined level of water in the pan at all times.

The invention is illustrated in the ing drawings, wherein- Figure 1 is a longitudinal, vertical section through my improved furnace showing certain accompany 'portions of the radiator unit in side elevation;

Figs. 2 .and 3 are transverse sections taken on the line 2-2 and 3--3 of Fig. 1;

Fig. 4 is a longitudinal, horizontal section taken on the broken line 4-4 of Fig. 1;

Fig. 5 is a view of one set of the outlet openings showing how all but the front one are restricted more or less by the use of baflles having different sized openings for the different sections;

Fig. 6 is a longitudinal section through one of the bafiies shown in Fig. 5, being taken on the line 6-6 thereof, as indicated, and

Fig. 7 is a fragmentary. sectional detail of the front end of the humidifier pan taken on the line 7-7 of Fig. 2, showing how the water level therein is maintained by a float-controlled water supply valve.

The same reference numerals are applied to corresponding parts throughout the views.

Gas fired furnaces have been built utilizing circular and other shaped burners, but I prefer to employ a long narrow burner 10 extending substantially-the full length of a narrow, elongated combustion manifold 11 of a. radiator unit 12 and having its pipe 13 for the delivery of its mixture of fuel and air extending from the middle thereof to the gas cock 14, at which point the usual shutter plate 15 is provided to permit regulating the inflow of air in the usual way. A pilot burner 16 is provided at the front end of the main burner and has connection through a. valve 17 with the gas supply pipe 18 at a point in front of the shut-off valve 19. Thus, the pilot burner is arranged to remain lit so long asthe valve 19 is left open. Another valve 20, under the'control of thermostaticallyecontrolled mechanism 21, shuts off the gas for the main burner according to the setting of a thermostat placed in' one of the rooms of the house being heated. The pilot burner 16 usually has a thermostat associated therewith heated by the flame thereof and electrically connected with the mechanism 21 and arranged in the event the flame is extinguished to close the valve independently of the thermostat previously referred to, whereby to avoid the condition of having the gas delivered to the main burner without a pilot light to ignite the same. This sort of control is so well known, there is thought to be no need for further explanation.

The radiator unit 12 is made up of a plurality of individual radiator sections 22 each having a pair of laterally spaced, substantially parallel hollow columns 23 I extending from both sides of the top of a lower housing portion 24 up to the opposite sides of the top of an upper housing portion 25, all cast in one piece. housing portions 24 of the radiator sections are flanged, as indicated at 26, and are arranged to fit snugly in abutting relation to form the com- The lower bustion manifold 11, and the upper housing portions 25 are similarly flanged, as shown at 27, to fit snugly in abutting relation to form the flue manifold 28. Lugs 29 on the lower housings 24 permit the bolting of the abutting sections together at their lower ends by short bolts 30. Through bolts 31 reach the full length of the outside of the combustion manifold 11 and serve not only to further draw the sections together, but also fasten the same to a front casting 32 and a back plate 33. The latter serves simply to close the rear end of ,the combustion manifold, but the former provides a compartment for the pilot light 16 and cock 14 at the outer end of the burner. 10. A cover plate 32' is provided for the casting 32 and provides a mounting for a door 34 having a window 35 therein affording access to the burner for lighting the same when the door is swung open, and a view of the flame to determine the results of adjustment of the cook 14 or shutter plate 15 when the furnace is being regulated. The plate 32' also has an air inlet opening 36 belowthe door 34 so that there is adequate supply of air to the burner for good combustion.

A pair of laterally spaced legs 37 reach downwardly from the casting 32 to rigidly support the front end of the radiator unit. The rear end thereof is movably supported by another leg 38 through the medium of trunnions 39 which have knife edges 40 seating in openings in lugs 41 provided on the upper end of the leg 38. Screws 42 thread through laterally spaced feet provided on the

legs

37 and 38, and are arranged to be adjusted to level theradiator unit 12 as a whole, regardless of unevenness of the floor on which the furnace is set, with the object of getting the burner 10 absolutely horizontal for most eflicient combustion, it being found that the flame tends and forth as the radiator unit expands and contracts in the operation of the furnace. In passing, it will be noted that another set of through bolts 43 are provided extending the full length of the flue manifold 28 and serve not only to draw the radiator sections together, but, also fasten a front plate 44 and a flue outlet casting 45 onto the opposite ends of said manifold, the former serving merely to close the front end of the manifold, and the latter being arranged, of course, to have a pipe attached thereto for communication with a chimney.

In operation, considering 'only the radiator unit thus far described, it is evidentv that the products of combustion are conducted from the combustion manifold 11 through the columns 23 of the plurality of radiator sections into the flue manifold 28, and thence to the chimney through the flue outlet 45. Now, assuming that cold, fresh air to be heated is being delivered below the radiator unit so as to flow upwardly therethrough to the hot air ducts leading to the rooms to be heated, it is evident that the transfer of the heat from the products of combustion to the air is efficient only in proportion to the radiation area afforded, that is, area of metal contacted by both the products of combustion and the air to be heated. A large amount of radiation area is secured by making the columns 23 of flattened cross-section so that the products flowing therethrough are spread out in thin streams from which the heat is dissipated from both sides through the opposed walls, the products being in heat transferring contact with these walls on v the inside, and the air being in heat transferring contact with the outside thereof. Additional radiation area is-built into small space by pro viding the flattened columns with longitudinal corrugations 46, the columns shown having radiation area equivalent to columns from 30% to broader, as should be evident from a consideration of Fig. 4, where these corrugations are shown to best advantage. The corrugationing is such that the troughs thereof in the opposed walls are in line with one another, as shown, so as'to form substantially tubular channels or passages 47 through which the products are caused to flow. In other words, the thin streams of products previously referred to are each split up into a multiplicity of separate streams, from which the heat is readily dissipated to the surrounding'air through the walls encasing the same from practically- .all sides. There is a very eflicient scrubbing action of the air on the columns in the passage of the air along the longitudinal channels on the outside thereof. The air is conducted along these channels, with minimum obstruction to flow, in straight paths from the lower ends to the upper ends of the columns. The special formation of the columns to obtain increased surface area is not, therefore, made at the sacrifice to unobstructed air passages. Where protruding knobs or radiating projections were provided, for example, there was too much obstruction to the flow of the air created thereby, and as a result, the air never had more than superficial contact therewith and the efficiency of operation was correspondingly low. The' channels 47 are, of course, not entirely separated, but are in communication with one another to the extent indicated in Fig. 4, but still theresult described is produced .to about the same extent as if the combustion manifold were connected with the flue manifold by as many parallel pipes as there are channels 47. The fact thatthe columns 23 are cast with the channels 47 in communication with one. another, makes it possible to clean out the columns with a flexible handled brush entered from the combustion manifold 11 and worked upwardly therefrom, the burner 10 being'preferably removed to give enough room. Still further increase in the efliiciency in the transfer of heat from the products of combustion to theair is secured by the additional radiation area afforded by longitudinal flanges 48 on the inner edges of the columns and similar flanges 49 on the outer edges thereof.

The efficiency of the furnace is also propor:

tionately high if the heat losses by radiation directly from the furnace itself are kept down to a minimum. In other words, the cooler the outside walls of the casing 50 are, the higher the efiiciency of the furnace is bound to be, because it is evidence that the heat in the radiator unit 12 is not being dissipated through the casing. The disposition of the radiator sections 22 edgewise with respect to the side walls of the casing exposes very little radiation area toward said walls, which obviously means a proportionately diminished dissipation of heat from the radiator unit 12 through the walls of the casing. In order further to cut down the heat dissipation, I provide the side walls 51 with inner walls 52 spaced therefrom so as to provide insulating air chambers 53. The back wall 54 is also provided with an inner wall 55 so as to form an insulating air chamber 56 for'a similar purpose. The front of the casing is made so as to form still another insulating air chamber 57. An inner wall 58 to which the front casting S2 'of the radiator unit "12 and its cover plate 32' are suitably secured, is

set in in the front end of the casing 50 sufllcient- 1y to provide the chamber 5'? in front of it. wherein the

valves

17, 19 and 20 and the thermostatic control mechanism 21 are received, and a door 59 constitutes the outer front wall for said chamber. The door 59 reaches substantially the full height of the casing and is hingedat one side thereof, as shown at 60, and provided at the other side thereof with a knob 61, the turning of which is arranged to lock or unlock the door-by the operation of latch rods 62. -When the door is opened, access may be had to the entire front of the furnace and all of the control valves are within easy reach. When the door is closed, the

furnace presents the neatness in appearance of as previously described. Thus, air for the burner is taken in by a direct path from in front of the casing. Cold, fresh air to be heated is delivered to the bottom of the casing through ducts 64 communicating with opposite sides of the casing, as shown in Fig. 4, and a hood 65 covers the top of the casing and has the hotair ducts represented in dotted lines at 66 in Fig.1 radiating therefrom in different directions. Since all sides of the easing are insulated and there is'minimum radiation of heat from the radiator unit to the walls of the casing, by reason of the arrangement of the radiator sections, as above described, it should be evident that'the-air admitted to the bottom of the casing through the ducts 64 will be heated evenly in its passage upwardly over the large radiation area afforded on the radiator unit 12 and distributed to the various parts of the building throughthe ducts 66. Theair is not s'ubje'ctedat any time to intensive heating, such as would tend to drive out its natural moisture content, but in the event the air is too dry, it is arranged to pick up moisture from the water in a humidifier pan 67 which is entered through an opening 68 in the inner front wall 58 and has outwardly directed flanges 69 on opposite sides thereof received in registering notches 70 provided in the flanges 43 for the support of the pan between the two rows of columns 23 directly over the combustion chamber 11. A plate 71-, forming the front wall of the pan 67. is arranged to be bolted to the inner front wall 58 of the casing, as indicated at '72. A water supply pipe 73 has an elbow connection 74 with a. valve 75 provided on the inside of the pan 67, and a float 76 controls the opening and closing of the latter so as to maintain a certain level of water in the pan at all times. Thus, the humidifying ofthe air'is always automatically assured and the operator never has to bother filling the pan. In passing, it will be observed that a plate 7'7 is bolted over a hand hole 78 in the wall 58 directly in line with the cover plate 44 provided, as

described before, at the front end of the flue manifold 28 of the radiator unit 12. -When the columns are being cleaned out as previously mento permit the removal of cleats 79 and baflies '80 so that the cleaning brush can be worked up all the way through the columns of the radiator sections. The purpose of the battles will now be described.

- A very important factor in the eificiency of the furnace is the matter of making all of the radiator sections 22 function alike; the flow of the products of combustion through all of the radiator sections has to be at substantially the same rate for maximum eiiiciency. The difficulty in securing such uniform operation of said radiator sections lies in the fact. that the draft efiect is not uniform at all points along the flue manifold 28; it is found that the heaviest draft is 'at the middle and the draft is lighter at the ends. I have, therefore, provided the 'baflies 80 in the outlets 81 of the columns 23, having different sized openings 81' provided therein for the different radiator sections to equalize the draft effect for all of the sections and thus tend to make the flowof the products of combustion through all of the said sections uniform. Fig. shows how the openings 81' in the various bafiies 80 for'the different sections compare with one another in size. The outlets for the front section are left uncovered, the full area of one of these openings 81 being represented merely by an outline at the left hand end of Fig. 5. I prefer to make the baflies 80 in the form of small flat plates cast to the form shown in longitudinal section in Fig. 6 providing below the opening 81' three distinct transverse ribs 82 separated by thin webs 83 such that one, two or all three of the ribs can be knocked out with a chisel to enlarge the opening 81' to the extent desired. By reference to Fig. 5, it will be observed that certain of the baflies have some of the ribs 82 knocked out for the purpose stated.

Below the ribs 82 is a panel 84 also separated from the ribs and from the rest of the body of the baflle by thin webs 83. Thus, it is possible to knock out this panel along with the ribs if a large opening is desired in the baflie. The baflie shown at the right hand end of Fig. 5 has all of the ribs 82 and panel 84 knocked out for that purpose. It is, therefore, evident that in the manufacture of .these baflies it is not necessary to make a half dozen or so different kinds of baflies with different sized openings; the workman installing the furnace uses the same kind of baiiles for all of the radiator sections and merely knocks out enough material at the opening 81' to enlarge the opening to the extent desired for any particular radiator section. The back of each bafiie is formed with inclined marginal edges 85 arranged to fit on complementarily formed seats 86 in the radiator sections defining the edges of the outlet openings 81, whereby to insure at snug fit. A hollow boss 87, cast on the front of each baflie, provides a recess 88 forthe accommodation of the end of the cleat '79, and the back wall of the recess 88 is made inclined at an acute .angle with reference to a vertical, as indicated at 89, and the ends of the cleat 79 are correspondingly inclined, as indicated in dotted lines in Fig. 3, so that the cleats '79 when entered in the recesses 88 and struck a light blow, will serve to wedge the baiiies 80 properly into place on their seats 86. Lugs 90 are cast in the radiator sections above the outlet openings 81' with sufl'icient room left between the openings and the'lugs for the upper ends of the baflies to be entered therebetween, and horizontally projecting lugs 91 are provided below said outlets to serve as supports for thelower ends of the baflies. Thus, both baflies of an opposed pair can be put in place and will not drop out before the cleat is inserted, which greatly facilitates the matter of installation. In the operation of the furnace, the baffles impose enough restriction on the flow of the products of combustion through the intermediate radiator sections so that the flow is no faster through these sections than through the sections at either end of the radiator unit. The inlets 92 for all of the columns are sufiiciently large so that there is never any danger of floating, because there is easy take-off of the products of combustion.

It is believed the foregoing description conveys a clear understanding of all of the important objects and advantages of my invention. While I have made reference to various details of construction, it should be understood that the invention, for the most part, is not particularly limited thereto, and many changes might be made without seriously departing from or sacrificing advantages of my invention. For example, while I have shown a furnace, the casing of which encloses a single radiator unit 12, it should be understoodthat I may connect two or more radiator units in series on the same gas supply pipe 18 and. build a single casing about the same with a single hood for the top thereof, that is, where a large building is to be heated and a single radiator unit would not give suflicient heat. In such a multiple unit furnace each of the radiator units is suitcombustion manifold to the flue manifold for discharge from the furnace, and a casing enclosing the manifolds and radiator columns and having a lower cold air inlet and an upper hot air outlet, the draft effect at the ends of the flue manifold being lighter than at the middle of said-manifold,

and means for restricting the passage of products of combustion into said manifold from certain of the radiator columns disposed intermediate the ends of said manifold whereby to cause all of said columns to function substantially the same.

2. In a furnace, the combination of an elongated fuel bumer, an elongated combustion manifold therefor, an elongated flue manifold above the latter, rows of spaced vertically disposed hollow radiator columns establishing communication between the two manifolds to conduct the products of combustion from the combustion manifold to .the flue manifold for discharge from the furnace, and a casing enclosing the, manifolds and radiator columns and having' an inlet and outlet for the admission and discharge of fluid to be heated, the draft effect at the ends of the flue manifold being lighter than at the middle of said manifold, and means for restricting the passage of products of combustion into said manifold from certain of the radiator columns disposed intermediate the ends of said manifold whereby to cause all of said columns to function substantially the same.

3. In' a hot air furnace, the combination of an elongated burner, a plurality of similar radiator sections each comprising an upper hollow housing portion and a lower hollow housing portion, open fore and aft, and one or more hollow columns joining said housings, said sections being arranged to be placed side by side with the upper housings thereof in abutting communicating relation and the lower housings thereof in abutting communicating relation to form an elongated flue manifold with the upper housings and an elongated combustion manifold with the lower housings, means for securing the radiator sections together, the said burner being disposed within the combustion manifold and extending substantially the full length thereof, whereby the products of combustion therefrom are distributed for passage upwardly through all of said columns to the flue manifold for discharge from the furnace, a flue outlet connection for said manifold, a clo sure member for one end of the combustion manifold, an open hollow inlet member at the other end of said manifold, said members being secured to the opposite ends of the manifold and being formed whereby to serve as supports for the opposite ends of said radiator unit, anda casing enclosing said radiator unit and having a cold air inlet and a hot air outlet, one of said supports being rigid and immovable, and the other of said supports being movable so as to allow for expansion and contraction of the radiator unit.

4. In a hot air furnace, the combination of an elongated burner, a plurality of similar radiator sections each comprising an upper hollow housing portion and a lower hollow housing portion, open fore and aft, and one or more hollow columns joining said housings, said sections being arranged to be placed side by side with the upper housingstherof in abutting communicating relation and the lower housings thereof in abutting communicating relation to form an elongated flue manifold with the upper housings and an elongated combustion manifold with the lower housings, means for securing the radiator sections together, the said burner being disposed within the combustion manifold and extending substantially the full length thereof, whereby the products of combustion therefrom are distributed for passage upwardly through all of said columns to the flue manifold for dischargefrom the furnace, a flue outlet connection for said manifold, a closure member for one end of the combustion manifold, an open hollow. inlet member at the other end of said manifold, said members being secured to the opposite ends of the manifold and being formed whereby to serve as supports for the opposite ends of said radiator unit, and a casing enclosing said radiator unit and having a cold air inlet and a hot air outlet, the front member having rig-id supporting legs depending therefrom to provide a fixed front support for the radiatoi' unit, and the member at the other end of the combustion manifold having a supporting leg pivotally connected therewith andarranged to rock 'to and fro when the radiator unit expands and contracts. a

5. In a hot air furnace, the combination of an elongated burner, a plurality of similar radiator sections each comprising an upper hollow housing portion and a lower hollow housing portion, open fore and aft, and one or more holl'owcolumns joining said housings, said sections being arranged to be placed side by side with the upper housings thereof in abutting communicating relation and the lower housings thereof in abutting communicating relation to form an elongated flue manifold with the upper housings and an elongated combustion manifold with the lower housings, means for securing the radiator sections together, the said burner being disposed within the combustion manifold and extending substantially the full length thereof, whereby the products of combustion therefrom are distributed for passage upwardly through all of said columns to the flue manifold for discharge from the furnace, a flue outlet connection for said manifold, a. closure member for one endof the combustion manifold, an open hollow inlet member at the other end of said manifold, said members beingsecured to the opposite ends of the manifold and being formed whereby to serve as supports for the opposite ends of said radiator unit, and a casing enclosing said radiator unit and having a cold air inlet and a hot air outlet, the front member having rigid supporting legs depending therefrom to provide a fixed front supportfor the radlator unit, and the member at the other end of the combustion manifold having a supporting leg pivotally connected therewith and arranged to,

rock to and fro when the radiator unit expands and contracts, the said structure including floor engaging screws on the supporting legs arranged to be adjusted so as to level the radiator unit irrespective of unevenness of the floor on which the furnace is mounted, the said adjusting screws permitting rocking motion of the last mentioned supporting leg.

6. In a hot air furnace, the combination of an elongated burner, a radiator unit comprising an elongated combustion manifold receiving said burner, an elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold for conducting the products of combustion from the former to the latter for discharge from the furnace, a rigid support for said radiator unit at one end of said combustion manifold, a support pivotally connected with the other end of said manifold and adapted to oscillate relative to the floor to support the other end of the radiator unit so as to permit expansion and contraction of said unit in operation, and a casing enclosing the radiator unit and having a lower cold air inlet and an upper hot air outlet.

7. A structure as set forth in claim 6 including two laterally spaced adjusting screws on each of said supports for the purpose of permitting leveling of the radiator unit longitudinally and transversely irrespective of unevenness of the'floor on which the same is mounted, the screws on the oscillating support permitting oscillation thereof.

8. In a hot air furnace, the combination of an elongated. burner, a radiator unit'comprising an elongated combustion manifold receiving said burner, an.elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold for conducting the products of combustion from the former to the latter for discharge from the furnace, means for supporting the radiator unit so that the front end thereof is rigid and the other end thereof is movable as necessitated for expansion and contraction of said unit in operation, and a narrow elongated casing for said unit having one end wall thereof secured to the rigid end of said unit, there being an air inlet opening into the combustion manifold at the rigid end thereof, and said casing having a lower cold air inlet and an upper hot air outlet.

9. A furnace, as set forth in claim 8, wherein the walls of said casing are insulated to minimize heat dissipation from the radiator unit therethrough, said casing including an insulating air chamber at that end thereof to which the rigid end of the radiator unit is secured, the said end wall of the casing to which said unit is secured constituting the inner wall of said chamber, said chamber providing a space therein for the valves and other controls of the radiator unit, and a door forming the outer wall of said chamber and arranged when opened to afford access to the valves and to the radiator unit.

10. In a hot air furnace, having a radiator unit comprising a combustion manifold, a flue mani-' removably disposed in said casing between and supported by two laterally spaced rows of radiator columns in a position above the combustion manifold and arranged to contain water for the humidification of the air passed through the casing, said pan being entered endwise through the end of the radiator unit between the.laterally spaced rows of columns.

11. A furnace as set forth in claim 10, wherein said casing has onewall thereof to which the radiator unit is attached, provided with an air inlet opening for the burner, said humidifier pan being removably inserted through another opening provided in the same wall.

12. A furnace as set forth in claim 10, wherein the columns have longitudinally extending flangesfor radiating heat therefrom, the said flanges on the inner opposed edges of the columns being provided with aligned notches, and said pan having longitudinally extending outwardly projecting flanges on opposite sides thereof entered in said notches for the support of the pan on the columns.

13. In a furnace comprising a combustion manifold, a flue manifold, and a plurality of hollow columns reaching from one manifold to the other and communicating through inlet openings with the combustion manifold and through outlet openings with the flue manifold, the inlet openings being all of substantially the same size, and the outlet openings being all of substantially the same size, bafiles for the one set of openings for imposing different restrictions on the flow of products of combustion through the different columns according to the draft effect for the different columns.

14. In a furnace comprising acombustion manifold, a flue manifold, and a plurality of hollow columns reachin from one manifold to the other and communi ating through inlet openings with the combustion manifold and through outlet openings with the flue manifold, the inlet openings being all of substantially the same size, and the outletopenings being all of substantially the same size, baffles for the outlet openings for imposing different restrictions on the flow of products of combustion through the different columns according to the draft effect for the different columns.

15. In a furnfie comprising a combustion manifold, a flue manifold, and a plurality of holl'. )V columns reaching from one manifold to the other and communicating through inlet openings with the combustion manifold and throu h outlet openings with the flue manifold, the inlet openings being all of substantially the same size; and the outlet openings being all of substantially the same size, a plurality of separate bafile plates having difierent sized openings provided therein, said bafiies being placed in the outlet openings to impose different restrictions on the flow of products of combustion through the different columns according to the draft eflect at each outlet opening.

16. In a furnace comprising a combustion manifold, a flue manifold, and a plurality of hollow columns reaching from one manifold to the other and communicating through inlet openings with the combustion manifold and through outlet openings with the flue manifold, the inlet openings being all of substantially the same size, and the outlet openings being all of substantially the same size, a plurality of separate baflie plates all of the same construction entered in the outlet openings, said baflie plates all having certain portions thereof at a predetermined elevation arranged to have openings formed therein, thedifferent bafiles having different sized openings made therein to impose different restrictions on the flow of the products of combustion through the different columns according to the draft effect at the different outlet openings.

17. In a furnace comprising a plurality of radiator sections disposed in a row providing an elongated combustion manifold, an elongated flue manifold and two rows of hollow columns joining the manifolds, the said columns being in communication with the combustion manifold through inlet openings, all of substantially the same size, and being in communication with opposite sides of the flue manifold through two rows of opposed outlet openings, all of substantially the same size, baflies on the flue manifold covering the two rows of outlet openings, the baflies having different sized openings therethrough to impose different restrictions on the flow of products of combustion through the different columns according to the draft effect at the different outlet openings, and ineans disposed between the two rows of bafiles for holding the same in place.

18. A furnace as set forth in claim 1'7, wherein each pair of baflles has a separate cleat reaching therebetween for holding the two baflles in place at opposite ends of the cleat.

19. A furnace as set forth in claim 17, wherein the baffles are substantially vertically disposed, there being lugs at the upper ends thereof provided in the flue manifold in spaced relation to the outlet openings for receiving the upper ends of the baflles therebetween, and ledges provided in the flue manifold below said outlet openings whereon the lower ends of the baffles are arranged to be supported, the ledges and lugs cooperating to keep the baffles from dropping out of place before they are secured.

20. In a furnace comprising a plurality of radiator sections providing a combustion manifold, a flue manifold and hollow columns joining the manifolds, the said columns being in communication with the combustion manifold through inlet openings all of substantially the same size, and being in communication with opposite sides of the flue manifold through two rows of opposed outlet openings, all of substantially the same size, the said inlets being of relatively enlarged size for easy take-off of the products of combustion from the combustion manifold, and the passages in said columns being diminished in size at the opposite ends so as to provide relatively smaller outlets so as to avoid too rapid flow of the products through the columns. 21. In a furnace comprising a plurality of radiator sectionsproviding a combustion mani fold, a flue manifold and hollow columns joining the manifolds, the said columns being in communication with the combustion manifold through inlet openings, all of substantially the same size, and being in communication with opposite sides of the flue manifold through two rows of opposed outlet openings, all of substantially the same size, the said inlets being of relatively enlarged size for easy take-off of the products of combustion from the combustion manifold, and the passages in said columns being diminished in size at the opposite ends so as to provide relatively smaller outlets so as to avoid too rapid flow of the products through the columns, and baffle means for the outlet openings for imposing different restrictions on the flow of the products of combustion through the different columns according to thedraft effect for the different columns.

22. In a furnace comprising a plurality of radiator sections providing an elongated combustion manifold, an elongated flue manifold above and substantially parallel with the combustion manifold, and pairs of hollow columns, one pair on each radiator section, joining the manifolds, the said columns having each pair branching ofi the opposite sides of the top of the combustion manifold, the inlet openings into the lower ends of said columnsbeing all of substantially the same size, the said columns having each pair communicating with opposite sides of the flue manifold through opposed outlet openings, all of sub stantially the same size, the said inlets being of relatively enlarged size for easy take-off of the products of combustion from i the combustion manifold, the products being divided in each radiator section between the pair of columns of said section, and the passages in said columns being diminished in size at the opposite ends so as to provide relatively smaller outlets so as to avoid too rapid flow of the products through the columns, and means for restricting the passage of the products of combustion into said'flue manifold from certain of the radiator columns disposed intermediate the ends of said manifold whereby to cause all of said columns to function substantially the same. i

23. In a furnace, the combination of a radiator unit comprising an elongated combustion manifold, an elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold for conducting the products of combustion from the former to the latter for discharge from thefumace, a rigid support for said radiator unit at one end of said combustion manifold, a support pivotally connected with the other end of said manifold and adapted to oscillate relative to the floor to support the other end of the radiator unit so as to permit expansion and contraction of said unit in operation, and a casing enclosing the radiator unit and having a cold air inlet and a hot air outlet properly disposed with respect to the radiator unit.

24. In a furnace, the combination of a radiator unit comprising an elongated combustion manifold, an elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold for conducting the products of combustion from the former to the latter for discharge from the furnace, a rigid support for said radiator unit at one end of said comsaid manifold adapted to oscillate relative to the tion, and a casing enclosing the radiator unit and having a cold air inlet and a hot air outlet properly disposed with respect to the radiator unit.

25. A radiator section for a gasheater or the like comprising a combustion chamber portion, a flue chamber portion having its center vertically above the combustion chamber portion, and a vertically disposed heat radiating conduit connecting the top of the combustion chamber portion with the side of the flue chamber portion, said conduit being of flattened cross-section in a plane transverse with reference to the axes of the two chambers whereby to stratify the products of combustion into a thin stream to facilitate dissipation of the heat therefrom, the said conduit being furthermore longitudinally corrugated so as to divide the same into a plurality of more or less separate longitudinal passages and thus cause the thin stream of products to be split up further into a multiplicity of separate streams from which the heat is dissipated through the walls of the conduit enclosing the streams on substantially all sides for efficient dissipation of the heat therefrom, 'the longitudinal corrugations affording longitudinal channels on the outside of the conduit arranged to conduct streams of air, with minimum obstruction to flow, in

straight paths lengthwise of the conduit to ab-' stract heat therefrom.

26. In a furnace, the combination of a radiator unit comprising an elongated combustion manifold, an-elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold for conducting the products of combustion from the former to the latter for discharge from the furnace, means for supporting the radiator unit so that the front end thereof is rigid and the other end thereof is movable as necessitated for expansion and contraction of said unit in operation, and a casing for enclosing said unit having one end wall thereof made rigid with the rigid end of the unit, the other walls being spaced from the rest of the unit, the casing having a cold air inlet and a hot air outlet properly disposed with reference to said unit,- the said casing being extended beyond the front end of, the radiator unit to provide a small insulating chamber, and a front closure wall for said chamber affording access thereto.

27. In a hot air furnace, the combination of a radiator unit having a combustion manifold, a burner received in said manifold, a casing for air to be heated enclosing the radiator unit from all sides, the front wall of said casing having an opening provided therein for directly admitting air to the combustion manifold to support combustion therein, the burner also having a fuel delivery pipe extending thereto through said opening, the walls'of said casing with the exception of said front wall being suitably insulated to minimize heat dissipation from the radiator unit, an insu- 28. A structure as set forth in claim 27, wherein the door has one or more air vents provided therein opposite the opening in the inner wall of said chamber for admitting air to support combustion in the combustion manifold;

29. A structure as set forth in claim 27, wherein the radiator unit comprises a flue manifold above the combustion manifold having a normally closed opening provided therein immediately behind the inner wall of the insulating air chamber, said in ner wall having an opening provided therein through which access is afforded to the flue manifold, the structure including a removable closure for the opening in the flue manifold and a re- 'movab1e closure for the opening in said inner wall.

30. A structure as set forth in claim 27, wherein the radiator unit comprises a plurality of spaced rows of hollow columns extending upwardly from the combustion manifold to conduct products of combustion therefrom for discharge from the furnace and arranged to radiate the heat therefrom, and wherein the inner wall of the insulating air chamber has an opening provided therein, the structure including a humidifier pan removably entered in said opening and disposed between the laterally spaced rows of columns of the radiator.

31. In a gas fired hot air furnace comprising a casing of elongated form having a lower cold air inlet and an upper warm air outlet, a gas heated radiator unit of elongated form disposed lengthwise in said casing, the same comprising an elongated lower burner manifold, an elongated upper flue manifold, the manifolds being substantially centrally disposed with respect to the casing with the flue manifold in a vertical plane above the burner manifold, and radiator columns extending upwardly from the burner manifold to the flue manifold to conduct products, of combustion to the latter, said columns being disposed substantially wholly to either side of the plane of the manifolds in the direct path of air rising through said casing from the inlet to the outlet, whereby to transfer heat thereto, the said columns being of flattened form whereby to stratify the products of combustion into thin streams in the passage thereof through said columns to facilitate dissipation of the heat therefrom, and said columns being furthermore conformed in cross-section toprovide a plurality of longitudinal passages therein to further divide the products into a multiplicity of streams in flowing the columns are furthermore conformed in crosssection so as to provide on the outside thereof a plurality of separate longitudinal channels between the longitudinal passages in the inside for the flow of air therein along the outside of the columns in heat transferring relation to the products of combustion conducted through the internal longitudinal passages.

33. In a furnace comprising a casing of elongated form having a lower cold air inlet and an upper warm air outlet, a radiator unit of elongated form disposed lengthwise in said casing, the same comprising an elongated lower combustion manifold, an elongated upper flue manifold, the manifolds being substantially' centrally disposed with respect to the casing with the flue manifold in a vertical plane above the combustion manifold, and radiato'rcolumns extending upwardly from the combustion manifold to the flue manifold to conduct products of combustion to the latter, said columns being disposed. submsaers stantially wholly to either side of the plane of the manifolds in the direct path of air rising through said casing from the inlet to the outlet, whereby to transfer heat thereto, the said columns being of flattened form whereby to stratify the products of combustion into thin streams in the passage thereof through said columns to facilitate dissipation of the heat therefrom, and said columns being furthermore conformed in cross-section to provide a plurality of longitudinal passages therein to further divide the products into a multiplicity of streams in flowing from the combustion manifold to the flue manifold, whereby to still further facilitate heat dissipation.

34. A furnace as set forth in claim 33, wherein the columns are furthermore conformed in crosssection so as to provide on the outside thereof a plurality of separate longitudinal channels between the longitudinal passages in the inside for the flow of air. therein along the outside of the columns in heat transferring relation to the products of combustion conducted through the internal longitudinal passages.

35. A radiator section for a gas heater or the like comprising a combustion chamber portion, a flue chamber portion having its center vertically above the combustion chamber portion, and a vertically disposed heat radiating conduit connecting the top of the combustion chamber portion with the side of the flue chamber portion, said conduit being of flattened cross-section in a plane transverse with reference to the axes of the two chambers whereby to startify the products of combustion into a thin stream to facilitate dissipation of the heat therefrom, the said conduit being furthermore longitudinally corrugated so as to divide the same into a plurality of more or less separate longitudinal passages and thus cause the thin stream of products to be split up further into a multiplicity of separate streams from which the heat is dissipated through the walls of the conduit enclosing the streams on substantially all sides for eflicient dissipation of the heat therefrom.

36. In a furnace, the combination of a radiator unit. comprising an elongated combustion manifold, an elongated flue manifold, and spaced hollow columns extending from the combustion manifold to the flue manifold to conduct products of combustion from the former to the latter for discharge from the furnace, a rigid support for said radiator unit at-oneend of one of said manifolds, a support pivotally connected with the other end of said manifold to oscillate relative to the floor in the expansion and contraction of said unit in operation, and a casing enclosing the unit and having a cold air inlet and a hot air outlet.

3'7. In a furnace, the combination of an elongated radiator unit, a rigid support for the radiator unit at one end thereof, a support pivotally connected with the other end of said unit and adapted to oscillate relative to the floor in the expansion and contraction of said unit in opera-- tion, and a casing enclosing the unit and having a cold air inlet and a hot air outlet.

38. In a furnace comprising a casing having a cold air inlet and a warm air outlet, a radiator unit disposed in said casing between the inlet and outlet, the same comprising a combustion manifold and a flue manifold in spaced relation to one another, and hollow radiator members extending from the combustion manifold to the flue manifold to conduct products of combustion from the former to the latter, and in so doing transfer heat from the surface of the members to the air circulating throughthe casing from the inlet to the.outlet, said hollow radiator members being of flattened form so that the thickness of cross-section is small in relation to the width whereby to stratify the products into correspond.- ingly thin streams'in the passage thereof through said members and facilitate dissipation of heat therefrom, and said hollow radiator members being furthermore conformed in cross-section to provide a plurality of laterally spaced longitudinal passages therein having restricted communication substantially their full length in which passages the thin'streams of products are sub-divided into a multiplicity of laterally intercommunicating streams in flowing therethrough, whereby further to facilitate heat dissipation, the ends of said hollow radiator members being formed so that all of said longitudinal passages communicate at their ends directly with the combustion manifoldand flue manifold.

39. A furnace as set forth in claim 38 wherein the hollow radiator members are furthermore conformed in cross-section so as to provide on the outside thereof a plurality of separate longi tudinal channels between the longitudinal passages in the inside, whereby to permit the flow of air along the channels on the outside of the members in intimate heat transferring relation to the products of combustion conducted through the internal longitudinal passages.

40. A unit for a sectional furnace comprising a combustion chamber portion, a flue chamber portion in spaced relation to the latter, and a hollow radiator member connecting said portions to conduct products of combustion therebetween, said hollow radiating member being of flattened form so that the thickness of cross-section is small in relation to the width, whereby to stratify the products into correspondingly thin streams in the passage thereof through said member and facilitate. dissipation of heat therefrom, and said hollow radiating member being furthermore conformed in cross-section to provide a plurality of laterally spaced longitudinal passages therein having restricted communication substantially their full length in which the products are subdivided into a multiplicity of laterally intercommunicating streams in flowing therethrough, whereby further to facilitate heat dissipation, the ends of said hollow radiating member being formed so that all of said longitudinal passages communicate at their ends directly with the combustion chamber portion and flue chamber portion.

STA NLEY H. HOBSON.