US2013237A

US2013237A - Gas-fired hot air furnace

Info

Publication number: US2013237A
Application number: US512803A
Authority: US
Inventors: James M Funk
Original assignee: Geo D Roper Corp
Current assignee: Geo D Roper Corp
Priority date: 1931-02-02
Filing date: 1931-02-02
Publication date: 1935-09-03
Anticipated expiration: 1952-09-03

Description

sept. 3, 193s. M FUNK 2,013,237

GAS FIRED HOT AIR FURNACE Sept. 3, 1935. J. M. FUNK GAs FIRED HOT AIR FURNACE 4 Sheets-Sheet 2 Filed Feb. 2, 1931 V @fr P @j Q) Q) (D @iw wwwwwww Sept. 3, 1935. J. M. FUNK GAS FIRED HOT AIR FURNACE 4 Sheets-Sheet 3 Filed Feb. 2, 1951 Sept. 3,1935. J. M. FUNK GAS 1" IRED HOT AIR FURNAGE Filed Feb. 2,' 1931 4 Sheets-Sheet 4 Patented Sept. 3, 1935 UNITED STATES PATENT OFFICE mazzi Gas-man no'ryam Emacs James M. Funk, Rockford,

lllnndnortoGemD.

'Roper Corporation. Rockford, lll., a corporation of Illinois invention relates to hot air furnaces .generally', but has special reference to gas-fired hot air furnaces, and Still'moie particularlyv one of the so-called hot blast type, that is, one which ls arranged to operate with forced 'draft of the air tobeheatedinsteadof relying onnatural draft.

The'principal object of mv invention is to de- Sign and construct the various portions of the furnace with special reference to forced draft operation with a view to maximum eficiency.

'For example, to further this object, all heated surfaces are so arranged that they may be easily and completely traversed by the air to be heated. and whereverl possible and desirable, the parts are made of streamline form-l tovminimize head resistance and at the same-time insure more complete contact of-tle air with the heatedsurface.

'l The ilues conducting the products of combustion areaccordingly streamlined and this gives the important advantage of causing the products of combustion to be spread out into thin streamsfor 'the most eiiicient heat exchange through the walls of these flues with the air coming in contact with thev outside thereof. To further insure good. eiiiciency, I provide an air moving apparatus V employing an air screw propeller instead of` an ordinary rotary fan, and provide in connection with this propeller a specially designed shroud for increasing its air moving eiiiciency to create the desired draft without excessive power consumption and thus cause the dellvery'of a large-quantity of warm air as against a small volume of hot air produced with a furnace operating with Y natural draft. This principle of operation ac-4 counts for-the greatly increased efllciency, 'As

against an eiiiclency of 60% or even less, which is regarded'as the best obtainable with most ordinary gas-fired furnaces with which I am,fa

afurnace made in'accordance with my invention has shown an eiciency of better than 90%. which, ofcourse, is sufdcient evidence of the soundness of the principle of operation. l

The furnace embodies numerous features of Y novelty, among the more important of which may be enumerated the following: o,

(1) The 'arrangement of the' cold air inlet 'and` warm air outlet in such rlation to the ue system for the counter-flow of air to the products of combustiomthe cold 'air after entry being thereby caused tocontact with the coolest iiues and the warmest air before leaving being caused to have contact with the hottest flues. This gradual heating of the air in the course of Aits passage through the furnace casing is conducive toward higher efficiency and leaves the air in a better condition thanis otherwise'obtained. (2) The provision in the ilue system of intermediate mixing chambers to tend toward more uniform distribution of the products to the sues 5..

in each bank, and a substantially uniform temperature of the products in the different iiues of any bank,`all of which makes for higher efciency Vby reason of uniform heat exchange by all of the provided with a drain to off condensation, 20 .so that the chamber serves several purposes.'

namely,as a mixing chamber, a clean-out, and a condensation trap. 1

(4) The provision of a separate air jacket for the fire-box discharging to the same outlet with 25 the air circulated over the iiue system. A small fan is provided to produce a forced draft through this jacket and is suitably mounted directly on the armature shaft of a motor provided for driving the vair screw propeller. A belt connection 30 serves to drive the propeller from the motor at the proper speed reduction. Incidentally, I provide a ships funnel in the warm air outlet for the discharge of the'warm air from the aforesaid jacket into the 'main stream, said funnel being so 35 disposed that. the main air stream impinging thereon creates enough of a reduction in preslargerV air screw propeller are, of course, disposed 4o inside the furnace casing so that the operation thereof creates a draft and cold air is drawn in past the outlet end of the flue system and therebypreheate'd before being'forced by the propelletV and fan to circulate past the hotter sur- 45 faces, of the furnace. Y

These and other features of the invention will receive Vfurther mention in the course of the following description, in which reference is made to the accompanying drawings. 1 In the drawings-e- 50 Figure 1 is a transverse, vertical section through a furnace made in accordance with my invention;

Fig. 2 is a Vfragmentary view taken on the line 2-2 of 6, showing the automatic controls provided in connection with the furnace;

the une 1"-1 of Fig. 2;

sectional detail lon the line 9*-9 of Fig. 2.

` shown at 28 'ispne which is manually a ing the full lengthv of the main burners, serves 'to insure lightingo! the main burners 'Ihe same reference numerals are applied to corresponding parts throughout the views.

Referring to-Figs. 1, 2 and 6-9, the numeral 9 is applied to the re-box which constitutes the supporting base for the gas-fired radiator, indicated generally by the numeral l0, and provides the combustion chamber il and secondary air chamber i2 above and below theburners I3. The latter are elongated, as clearly appears in Fig. 6, and extend substantially the full length of the hre-box, andhave an elongated pilot burner or inspirator M disposed therebetween. A lower opening I5 in the front wall of the fire-box admits air to the secondary air chamber l2 and primary air to the mixers i6 for the main burners and mixer AIl for the pilot burner. Another opening, which is normally closed by a door I8 hinged on the front wall, aiords access to the combustion chamber for the purposes of lighting ,the

furnace. The burners are suitably supported on Y cross members I8 in spacedvrelation to one another to permit the proper flow of secondary air upwardly between the burners to support combustion, and baiiies 29 are provided at the sides and ends of the fire-box, the inner edges of which also have the proper spaced relation to the burners for good aeration of the ports adjacent Y the same, whereby to insure good combustion. The gas is supplied to the burners through pipe 22 and the intermediate control mechanism numbered Z3-25.? 23 is a pressure regulator whose function isobvious. 2d automatically operated valve," the opening andclosing of which is normally taken eareof by means of a thermostat in one of the rooms being heated. 25 is a pilot safety valve in the bypass line 26 leading to the pilot burner. 2l designates a. safety device cooperatng with the pilot burner M, and the heang of which bythepilot burner so long as the latter remains lit controls the valves 24 and25 by virtue of electrical connection therewith, so that the same are closed in ease of extingmshmnt of the pilot light, and preventV the loss of gas and the possible danger of asphyxiation. The valve operable to shut 4oif the flow ofjgasfto the main burners wheneverit'is desired 'to dispense with heating for periodof There is no particular novelty in the structure thus far described, exceptingjin'so far as the form and relationship of the burners |37 are concerned. The burner I4 maintains the draft upon the shutting o of the main I3, and, by reason of itslextendthe full lengththereof when they are turned on.

`The Il has two banks of vertically disposed flues 30 communicating at theirlower ends with .the'top f the combustion `chamber Il and at ilitiirllpllelA ends with thebottomof aheaderv manifold or chamber 3l.

' In most the products of combusucente; a to the chamber ucts of combustion to bring about much of a heat exchange between the products and the air circulated past the dues. According to my invention, I provide a more elaborate ilue system to the end that the products have ample-opportunity to transfer the heat to the'air and the products escape up the smokestack at a much lower temperature than is otherwise the case.

I provide one bank ofues 32 reaching laterally from the upper end of the header 3 I, downwardly at an acute angle to the horizontaLand communicating with the side of another header manifold or mixing chamber 33 near the 'bottom thereof. Still another lbank of -ues 3d double back abovetheues 32 and extend from the top of the header 33 upwardly-'atan acute a-gle and communicate with the vsidefof an-outlet manifold 35 at the bottom of the latter. The manito mix before delivery to theues 32. 'Llhat'l makes for delivery of the products under the same pressure to all of the'ues 32 and at suhstantially the same temperature. The rate of flow of the products will, therefore, be the same` throughout the bank of flues 32. Y Abaie 38 isA preferably provided in the chamber -3I to cause good mixture of the products from the 'twobanks of hues 30 and equalize the distribution of products from the chamber- 3l to theues' 32 to insure heatingthe latter all to about the same degre. With all of the flut-3S 32 'heated'a1ke, it is obvious that the eiiiciencyofV the heatexchange with the air comingin contact with these :dues

is bound to b'e higher than "would otherwise be` the case. The products discharged from the ilues 32 into the chamber 33 are given 'another opportunity `of mixing before they are passed through the flues 34 tothe outlet manifold 35,V ,and this accounts in like manner for the even heating of all of the lues in that bank and Yaccordingly ahlgher ediciency of heat exchange.

The :dues Y32 and 34, itwill be observed, slope Ilowntiardly towardllhem'anfold 33. This sloping of the iiues 32 isprimarily with aview to making the products take atortuous course to insure better-heatexchange with the air circulated past the due system. However, this sloping of 4the ilues -32 and has another advantage, .and that is, that any condensationon the walls of these orf-'thel dues, manifolds, conduits and other 'j metal parts with which moisture-laden products would otherwise come in contact. The fact that .the products are 'ona downward course whenthey enterthe Amanifold 33 and are forced to reverse plate VIll may be and their direction of ow in order to enter the ilues 34, increases the tendency for moisture to be deposited in vthe trough 39. The manifold 33 is disposeddirectly alongside the side wall 4l of the casing 36, and an opening 42 is provided in said wall affording access directly to the inside of the manifold and to all of the

iiues

32 and 34 communicating therewith. The wall 4l is used as al support for the manifold -33 and the lsystem of fiues communicating therewith, as by suitably fastening the ange 43 provided on the manifold to the inside of the wall 4I. A cover plate 44 fastened on the outside of the wall 4I for easy removal serves to close the opening 42 and form that side of the manifold 33. The inside of the some suitable heat insulation material faced by a plate of stainless steel nr other rust-resisting material, whereby to minimize `heat loss throughthe wall of the furnace at this point. Such insulation has not been shown as a matter of convenience, and it will also be understood that it is only for the sake of convenience that the Vother walls of the casing 36 are not shown insulated. All walls will be suitably insulatedA somewhat along the lines disclosed in the co.

. pending application of Stanley H. Hobson, Serial No. 334,553-led August 9, 1929, or in any other suitable or preferred manner. The removal of 'the cover plate 44 Venables one to reach all of the flues- 32 and 34 for,cleaning from the outside of the casing. The fiues are accessible through the door I8 and an opening 45 in the front wall of the casing for which a door may or may not be provided, as desired. It is, ofcourse, obvious that the cleaner the ilues are kept, the more efficient will be the heat exchange with the air circulated pastthe ue system. It is for that vreason that I have arranged for such convenient access to the flues.

The radiator I0 is set approximately 4in the middle of the casing and forms part of a partition wall separating the inlet chamber for incoming cold air from'the outlet chamber 41 for outgoing warm air. Thus, a plate 48 reach-v ing the full length of the casing cooperates with the manifold 3| to form part of this wall. Another plate 45, also reaching the full length of the casing from the manifold 3l downwardly to thel lire-box 9, forms another part of this wall. 'Still another plate 50, reaching substantially the full height of the fire-box and beyond both ends thereof, cooperates with vertically disposed strips 5l at the front and back walls of the casing to complete the lower portion of the partition wall,

in addition to forming one side wall of an air jacket 52 for the re-box 9, as will soon appear. The plate 49 has a circular opening provided therein at the approximate center thereof dened by `an annular shroud 53. An annulus 54 surrounds and reinforces the shroud 53. The shroud 53 is provided for an air screw propeller 55 disposed centrally with respect toit and preferably slightly forward with respect to the plane of the back thereof, as best appears in Figs. l and 5,Vv

such location of the propeller being important from the standpoint of bringing about the proper cooperation of the shroud with the tips of the blades of the propeller, with relation to which the shroud makes an oblique angle. The propeller 55 is carried on the end of a shaft 5B receivedin bearings 51 provided on Athe top of the frame 58. The bearings 5l may be of `a type which, when once packed with lubricant, will not require attention more than once a year or so,

preferably is covered with but I have shown piping 51' extended to these bearings from the side wall 4I to permit supplying oil or grease to these bearings from the outside of the furnace casing to make it unnecessary for one to open the casing to take care of this servicing of the furnace. The frame 58 is mounted on the oor alongside the radiator I0 -in the inlet chamber 46 and preferably has sound and vibration-deadening material interposed in the fastenings therefor. which are indicated generally by the numeral 59. Anelectric motor 60, which also is preferably resiliently mounted on the oor behind the frame 58, as at 6l, has a small pulley 62 on the armature shaft thereof in connection with which a belt 53 is used to transmit drive to thepropeller through. another pulley 64 pulley 64 to provide for the desired speed reduction bevvtween the motor and the propeller. I preferito use an air screw propeller like the one shown at 55 instead of an ordinary'rotary fan because of the established fact that a propeller of this kind is capable of moving a much larger volume of air and still require less power consumption. `The operation of air screw propellers is so generally known that it is unnecessary to go to any further length than tostate that resistance of the air tending to retard the rotation of such a propeller results in a reaction which accounts for the sucking of a large amount of air into it, and that ordinary rotary fans, not of the air vscrew type, do not possess that property. The lshroud 53 cooperates with the tips of the blades of the propeller so as to prevent a flowof air from the working face around the tips of the blades into the partial rvacuum on the other side.- The shroud, therefore, enables the propeller to move still more air, by avoiding the losses referred to..

of the desired amount of air through the furnace casing is definitely assured.

In the operation of the propeller, cold air is drawn in through a suitable number of cold air `ducts 65 communicating-with the top of the inlet chamber 45 and air is propelled from thework-f ing face of the propeller through the opening dened by the shroud 53 past the flues 30 into the mounted on the propeller shaft. The is somewhat larger than the pulley 6 2" outlet chamber 41 from whence the air is disl charged through a suitable number of wann` air.

lead to the rooms to clear that thecold into the inlet chamducts 66, which, of course, be heated. It is, of course, air immediately after entry ber 46 encounters thel outlet-manifold 35 ues 34 leading thereto. The surfaces of these parts are naturally not at as high a temperature as the surfaces of other parts of the ue system not as remote with reference to the nre-box, but there is, nevertheless, suicient heat for the cold airentering and coming in contact therewith to havethe temperature thereof raised appreciably. The air thus partially heated next comes into contact with the fiues 32, which, of course, are at' a higher temperature than the ilues 34 and outlet manifold 35, so that the air derives further andthe' Y to the products of combustion, as just described,

has been demonstrated'by test to give the highest obtainable emciencynuch higher than is obtained with furnaces where the products and the air to be heatedl take the same general direction of flow.

Attention is now called to the fact that I have provided the iiues as well as the

flues

32 and 34 of streamline cross-section. This is oi advantage in three ways-rst of all, parts having such form have less head resistance in any air current, so that the ues so formed impose less resistance to the circulation of the air past the same, as will be readily understood by those versed in aeronautics. In a forced draft or hot blast furnace particularly, it is obvious that anything which tends toward less obstruction to the now is highly benecial. Secondly, ues of this cross-section do not give rise to dead air spaces to the Windward side of the ues, but allow the air owing past the same to completely envelop and have more .intimate contact with the entire surface,which, of course, makes for more eilicient heat exchange. Thirdly, the :dattening of the iiuesto the streamline cross-section means a spreading out of the products ofA combustion into thin Streams, thus allowing the walls of theV tubes to pickup the heat from the products with facility and give it 'ofi to the air coming in contact with the outside of V'these walls. All of these advantages arenot merelytheoretical but actual test has shown a stepping up in eiciency approximately over what was obtained with other gas-fired furnaces. That is to'say, instead of an eiciencyof 60% or even less secured with other gas-red furnaces, regarded as reasonably eicient, a furnace made in accordance with my .insulated to minimize heat loss.

Vari'opening 69 therein, and a Yupper end of the wall 61 Vwhat I call ashipsY-funnel 12, the purposeof which is hereinafter described, so that when the inventionlhas shown an Vefficiency of 90% or better. In passing, vit will be observed that the outlet manifold 35 has also .been formed of streamline crcss-sectionwith the same objects in view as discussed above in regard to the iilues. It will also be "seen that the ues 30 of the one bank are disposed in staggered relation to the iiues of `the other bank, as appears in Fig. 5. This is for the purpose of exposing the yiiues remote from the propeller in the air stream instead of leaving theml in the slip stream of the flues in the other bank.' In. passing, attention.

may also be called to the somewhat related feature Aof the special curvature of the bottom wall toward the top o'f the outlet chamber 41 with loss in velocity. Ikhave found that by giving the wall 61a. parabolic curvature there is and the operation is not attended with objectionable noise ysuch asf must otherwise be tolerated. Thevwall 61A may be and preferably is 'Ihe wall 61 is suitably .provided with a watervtrough 68 `se t in pipe 10 extends lengthwise in this trough-and of holes in the'bottom the delivery of water at a rate-determined by. the

l adjustment of a valve II provided on theoutside of the'furnace casing (s'ee' Fig. 6). j'lh'e trough.

A toward the in Vspaced relation to 6l ispurposely placed far enough vulve reopened ywide enough there win befan of water when the furnace is tends to deiiect 61 of the outlet chamber 41, the purpose of Vwhich is to defie'ctrthe air stream .upwardly through the opening 82 of the ships funnel 12. of course, supDQrted onvone end l 88 and may be supported at the other end inzany has a. suitable wall thereof for mounted overflow of water from the trough and the water will form a thin lm or sheet on the wall 61 between the trough 68 and funnel 12, whereby to provide for effective humidication of the air. It

is obvious that since the air is deected by conburners I3 simultaneously with the stopping .of

the motor, and it will be evident that an automatic shut-off valve could also be provided in vconnection with the pipe 16 to stop the delivery automatically shut lThe jacket s2 furthe nre-box 9 received brief mention above. 'I'his jacket completely encloses the'four'sides of the iire-box, as best appears-in Figs. 1 and 6. The plate 50, as indicated above, formsy one side wall; another plate 13 forms the opposite side wall, Vand there are end walls at 1liV and15, as appears in Fig. 6, the wall 15 terminating just above the door i8, as shown in Fig. 7.

Now, an opening 16 is'provided in the wall 5D' l .near the bottom of the jacket, and another opene4 ing 11 is provided in the opposite wall 13 at the top of the jacket, and airis arranged to be supplied through the opening 16 for circulation through the jacket about the four sides ,of the nre-box from bottom to top to be heated by contact with these hot Walls, andthe air so heated isan-anged to be discharged through the opening l1 into the outlet chamber 41. The opening 16 is elongated almost to -the full length of the fireboX so that the air admitted to the jacket 52 through this opening will come in contact Awith the re-box the full length thereof.V I provide a fan 18 on the armature shaft of the motorA 60 in front of the pulley 62 to provide forced circulation of air through the jacket 52. A duct 19,

which is generally funnel-shaped, has the small` n 'end thereof formed to provide a circular air in- 8i! deiinm g The curvature of thetop and this duct as-shdwn in Figure V1 the air 'so that itis discharged upwardly through the opening 16 into. the` jacket 52 in the general direction of the' opening 11 at the opposite side of the jacket. Warm air is therefore delivered at ably the full length o f the wall 13. Another duct `III is provided to direct the warm air discharged from the opening11 upwardly through the open#- 'rhe duct 1c onthe ilanges Vsuitable manner, as for.. exampl by'vmeans of` ross me'mbers 83 on the frame 58.1 Theyduct 8| is fastened to" the

walls

61 and 13, asv indicated.

Ain a shroud, and the sameY is aredtoward the Y to an elongatedrec- 4-55' an appreciable velocity 11 which extends V prefere` In operation, thefan 18 will be driven at a-higher Vspeed than the propeller 55 due to"itsbeing suction created-in the operation orrhisjfauffurther insures good intake" of cold airthroughfthe ducts and, of course, the air 'delivered-through directlyvon the armatureshaftgz'he the duet 1s co the jacket sz is preheated-wreason of its having had contact with theiues 32 und u andthe outlet manifold as.

amasar 4 of the refbox. 'In other words, the countervertically disposed primary flues flow principle of operation -applies to this portion of the furnace as well as to the other; The warm air discharge through the duct 8i into the outlet chamber 41- goes with the warm alrclrculated by the 'propeller 55 and is, of course, discharged 'with it throughthe warm air ducts 55'.

Owing to the fact that such a small fan is used and it is out .of 'the question to streamline the nre-box and there is, consequently, more or less obstruction to the flow of air through the jacket,

.I prefer to provide the funnel 'l2 for the purpose of accelerating the flow through the jacket 52. In other words, the strong draft created by .the propeller 55 over the back ofthe funnel 12 creates sufficient reduction in pressure at 'the opening 82 to accelerate the now of air` throuh the jacket 52. e Y

It is believed the foregoing description confveys a clear understanding of all of the objects and advantages of my invention. The invention is susceptible of a considerable amount o f modiiication without sacricing the more important advantages that have been outlined. The appended claims have, therefore, been drawn to embrace all changes coming within the spirit and scope of the invention.

1`. In a furnace, the combination of `a fuel, burner, an elongatedflre-box therefor, an elongated manifold above the latter, substantially establishing communication between the fire-box and manlfold to conduct products of combustion from the former to the latter, a casing enclosing the aforesaid elements, the inside of the casing being divided into an outlet chamber on one side of said fines and an inlet chamber on the other, side thereof, one or more openings provided in said casing for admitting cold air to the inlet chamber in said casing, another manifold in the inlet chamber, secondary ilues establishing communication between the, two manifolds for conducting 4the products of combustion from the rst to the second manifold, an air propeller disposed between the two sets of flues and in close proximity to the primary nues, and one or more openings provided in saidvcasing for discharging warm air from the outlet chamber in said casing,

, the said propeller being adapted in the operation thereof to cause a reduction in pressure in the inlet chamber, whereby to draw incold air, and create pressure in the 'outlet chamber whereby to discharge warm air under pressine. Y

2. In a furnace, the combination ofa fuel burner, an elongated fire-box therefor, an elongated manifold above the latter, substantially vertically disposed l'primary dues establishing communication between the fire-box and manifold to conduct products of combustion from the former to the latter, a casing enclosing the aforesaid elements, the inside of the casing being divided into an outlet chamber on one side of said nues and an inlet chamber on the other side thereof, one orV more openings providedfin said casing for admitting cold air to theinlet chamber in said'casing, a second manifold in the inlet chamber, secondary flues connecting the rst manifold with the second, a third manifold in the inlet chamber, other iiues'counecting the a second manifold below busticnbeing arrangedtobe conductedinone direction from the first manifold through the secondary ilues to thev second manifold and from thence in a different direction through the other fiues Vto the third manifold for discharge from the furnace, an air.propeller disposed between the primary and secondary flues and in close proximity to the primary flues, and one or more openings provided in said casing for warm air from the outlet chamber in said casing, the said propeller being adapted in the operation thereof to cause a reduction in pressure in the inlet chamber, whereby to draw in cold air, and create pressure in the outlet chamber whereby to discharge warm air under pressure.

3. In a furnace, the combination of a casing providing an inlet chamber and an outlet cham-- ber, a radiator in said casing comprising a firebox, a flue system embOdying a first and hottest bank of fines communicating directly therewith ,and one Vor more succeeding banks of ilues communicating with said hottest bank, and an outlet manifold communicating with the bank of ilues most remote from the nre-box for discharge of the products of combustion from the furnace,

one or more outlet openings for said casing for the discharge of warm air from the outlet chamber, an air propeller disposed in the one chamber in close proximity to the rst bank of hottest flues, whereby to secure direct impingement of air at highest velo'city upon said flues for an efficient heat exchanging scrubbing action, said propeller serving to create a reduction ipressure in'the inlet chamber and create pressure in the outlet chamber for the discharge of warm air under pressure, and one or more inlet openings for said casing to admit cold air to the inlet chamber when the reduction in pressure is created therein, said inlet openings beingso located on said casing with relation to the nue sysvtem for the counter-ow of air with relation to the Vgeneral directionofflo'w of the 'products of combustion in said system.

4. A gas furnace comprising an elongated firebox, an elongated manifold above the same, fiues extending upwardly box and connecting the latter with the manifold, the level of the first, iiues extending laterally from the side of' the rst manifold with downward inclination to ward the second manifold and communicating with the side of the latter at or near the bottom thereof whereby sation in the second manifold, means for conducting the condensation from said'manifold, a third manifold above the level of the second manifold and at a point between the nrst two manifolds, and ilues communicating with the second manifold at or near the top thereof and extending laterally therefrom with upward incllnation andkin Athe reverse direction to the second nues toward the third manifold to conduct products of combustion to the latter, the products being conducted fromv the first mantfold downwardly toward the second manifold in from the top of the fireto provide a trap for conden- 5, In a hot blast type furnace, the combination of a casing having A`one or more cold air inlet.

openings and one 'or more warm air outlet openings, -a heat radiator in said casing between said ings, aheat radiator in said casing 1between saidA inlets and outlets,- the saine comprising a re- .the warm air outlets for discharge from the casing, said air moving means comprising a'propeller or the like cooperating with the means encasing the ues, and a separate fan or the like cooperating with the means encasing the rebox, and means for driving said propeller and fan simultaneously. 1

6, In a hot blast'type furnace, the combination of a casing having-one or more cold air inlet openings and one` or more warm air outlet open- I- box, a header manifold for discharging products of combustion from the furnace, and rues for` conducting products from the fire-box tothe header manifold, means' whereby the fiues areencased, means whereby the fire-box is separately encased, air moving means for causing air to `be circulated under pressure'past the ues and past the nre-box to abstract heat therefrom, the air after' such'passage being conducted toward the warm air outlets yforrdischarge, from the casing, said air moving means comprising a propel.- ler or the likecooperating with the means encasing the ues, and a separate fan or the like Acooperating with the means encasing the rebox, and a shaft for driving the fan and propeller,

` eating withA the side ofthe arst manifold. at'or' the fan being mounted on theshaft and the latter having a reduction drive connection withv the propeller. t

' 7. Al gas furnace comprising an elongated-rire- Vbox having one 'or more burners therein, an elongatedv manifold -above the nre-box, iiues extend- 4 ing upwardlyfrom the nre-box and communiv` eating with the bottom of the manifold, one or more other elongated manifolds, iiues communinearthe top thereof and extending therefrom for communication with one lof the other manifolds,

the inlet chamber,'one or more warm air outlet openings in the upper portion of -the casing communicating with the outlet chamber, a deecting wall in the outlet chamber for deiiecting the air' after passing the-nues from a substantially horizontaldirection of flow upwardly toward the outlets, 'a power Voperated fan or the like disposed in the-inlet chamber adjacent the fire-box' and arranged to force-air'to circulate about the firebox from the inlet chamberin the direction of the outlet chamber. and means for c directing the air after passng the lire-box upwardly through an opening provided in the defiector whereby to .discharge it with the other warm air in the direction of the warm air outlets. Y l

9. In a hot blast type furnace, the combination of a casing; a heat radiator disposed in an intermediate position in said casing dividing the same substantially vertically into'an inletchamber -on one side thereof and an outlet chamber on the vother side, the said heat radiator comprising a lire-box, ues extending upwardly therefrom to conduct products of combustion therethrough for heat transfer to the air. circulated past the outside thereof, and a manifold communicating with the upper ends of said iiues for discharge of the products from the furnace,

' a power operated propeller or the like disposed inthe inlet chamber in juxtaposition tothe Aiiues and arranged to Athrow air substantially horizontally from the inlet chamber past the "hues themanifold most remote from the re-b'ox having communication with `an outlet for: discharge l of the products of combustion from the furnace, Y `a'ii'id a baiilein at least the iirst manifold disposed to the second-nues.

8. 'In abut-blast type furnace, the combination 60 :of a casing,a twat-radiatorA disposed in an inter- A transversely with'respect tothe ilrst mentioned iiues ,whereby to equalize distribution of the products of combustionfrcm the iirst manifold mediate positionin' said casing dividingthe same .Isubstantiallyvertically into aninlet chamber on onelside thereof andan outletA chamber on' the other side, the said heat radiator'comprising a "nre-box, ues; extending upwardlytherefrom to `conduct products of combustiontherethrough for heat transfer to' the air circulatedY past. the

' outside thereof, ,and-a' manifold communicatingwith the upper` ends of's'aidj-iiues for discharge of the products'from-,the furnace, -a `power oper` atedpropeller or. the like disposed in the inlet chamber in juxtaposition to the nues and arranged fto throwsubstantially horizmitaily from theinlet chamber` pasttlie iluesinto the the fiues, one ox-,morecold air inlet openings for into the ouiiefchamber so as tu be heated by contact with the ues,'one or more cold air inlet openings for the inlet chamber, .one or more warm air outlet openings for the outlet chamber, and an airA jacket .for the 'fire-box, the same having a cold air inlet opening inthe lower portion thereof on one side'commuicatingwith the inlet chamber, and a warm-air outlet opening in the upper portion thereof atthe opposite side, the warm. air outlet opening having com- -mimication with the outlet chamber for the Vdischarge of the air heated by the rebox to the warm air` outlets. '10,'A furnace as set forth 9 wherein the .warm'air outlets are provided in the upper portion of the casing, thefurnace including a deflecting wall impinged by the air after passing the iiues and arranged to deflect the air upwardly toward the Vair outlets, a duct establishing communication between the warm;

air outlet of the air jacket and an opening providedin said deiiector wall, and a baille over the lastv mentioned opening foi'V deiiectlng the air coming from the iiues upwardly away from said opening, whereby toproduce a ships funnel eifect to accelerate thelcirculation offair through the air jacket.`

- `1i. 1n arnet blast t'ie combina" tion of a casing, a heat radiator disposed in an same substantially vertically into an inlet chamber on Yone side thereof and an'outl'et chamber',

on the other side, the saidheat radiator comprising a nre-box, ues extending'- upwardly thereintermediate position in said casing dividing the from to conduct products of there- A through Yfor,V heatV transfer .to the air circulated past the --outside thereof, anda manifold com- K`municating with the upper ends of said'iues for discharge of the products from the furnace, a power operated .propeller orztli'e like in,

the inlet'chamber in juxtapositionr'to 'the'iiues A outlet chambesoastobe heated by contact with" andai'ranged to throw air substantially hori- .zoniany :famine inietfcimmber msi-'luie nues 75Y` into the outlet chamber so as to be heated by contact with the ilues, one or more cold air inlet openings communicating with the inlet chamber, the said propeller when operated creating a reduction in pressure in said inlet chamber to cause air to be drawn through said inlets toward the propeller, secondary ues communicating with the manifold vand disposed between the inlets and the .propeller to provide an additional vpass of the products of combustion in the inlet chamber for contact of the incoming cold air whereby to preheat the same before contact with the rst flues, one or more warm air outlet openings in the upper portion of thecasing communieating with the outlet chamber, a deilecting wall in the outlet chamber for deecting the4 air after passing the ues from a substantially horizontal direction of flow upwardly toward the outlets,

i an air jacket for the fire-box, a separate fan or the like arranged to produce forced circulation of air through said jacket from the inlet chamber toward the outlet chamber, and means for direct- -ing the air leaving the jacket upwardly toward the warm air outlets for discharge along with the other warm air.

12. In a furnace, the combination of a firebox, a manifold, primary ues establishing direct communication between the fire-box and manifold to conduct products of combustion from the former to the latter, an enclosing casing for the aforesaid elements, the same being provided with one ormore inlet and outlet openings on opposite sides of the ues-for the admission of cold y air and the discharge of warm air from lthe casing, off-take fiues communicating with the manifold and disposed between the intake openings and the first mentioned primary flues, and an air propeller disposed between-the primary fiues andv the off-take ilues in close proximity to the primary flues whereby to secure direct impingement of air at -highest velocity upon the primary fiues lfor a scrubbing action and effectively transfer heat to the air from the products of lcombustion, and whereby at the same time `to secure circulation of air at lower velocity about the off-take fluesV for preliminary heat transfer therefrom.

13. In--a furnace, the combinationof a casing, a heat radiator disposed therein between an inlet chamber and an outlet chamber in the casing, the said heat radiator comprising a ilrebox and vheat `radiating members communicating therewith for conducting products of combus- ,tion therefrom,` a': power-operated propeller or the like disposed in the inlet chamber in juxtaposition to the heat radiating members and arranged to throw air past the same into the outlet chamber so as to be heated by contact with said members, one or more cold air inlet openings for the inlet chamber, one or more warm air. outlet openings inthe upper portion of the casing communicating with the outlet chamber, a detlector in the outlet chamber for deflecting the air from the heat radiating members upwardly toward the outlets, means whereby air is circulated from the inlet chamber about the re-box to abstract heat .,therefrom, and means for conducting the air from the last mentioned means for discharge jointly with the other warm air through the warm air' outlets.

14. In a hot blast type furnace, the combination of a casing, a heat radiator disposed in an intermediate position in said casing between an inlet chamber on one 'side thereof and an outlet chamber on the other side, the said heat radiator comprising ame-box, nues extending upwardly therefrom to conduct products of combustion therethrough for heat transfer tc the air circulated past the outside thereof, and a manifold communicating with the upper ends of said ues for discharge of the products from the furnace. a power operated propeller or the like disposed in the inlet chamber in juxtaposition to the ilues and arranged to throw air substantially horizontally from the inlet chamber past the ilues into theoutlet chamber so as tobe heated by contact with the ues, one or more cold air inlet openings for the inlet chamber, one or more warm air outlet openings for the outlet chamber, an air jacket for the nre-box, the same having a cold air inlet opening in the lower portionthereof on one side communicatingdwlth the inlet chamber, and a warm air outlet opening in the upper portion thereof at the opposite side, the warmV airoutlet opening having communication with the outlet chamber for the discharge of the air Lheated by the fire-box to the warm air outlets, and a power operated fanlor the like in the cold yair inlet opening in said air jacket.

15. In a hot blast type furnace, the combination of a casing, a heat radiator disposed in an intermediate position in said casing between an inletv the outlet chamber so as to be heated by contact with the fiues, one or more cold air inlet openings for the inlet chamber, one or more warm air outlet openings for the outlet chamber, and an air jacket for the nre-box having communication' on one side with the inlet chamber .and on the other side with the outlet chamber for the circulation of air to be heated about the nre-box, said jacket having communication with theinlet chamber in such relation to the direction of air ilow therein whereby circulation of air about the jacket is accelerated in the operation of the propeller.

16. A furnace as set forth in claim 9 wherein the warm air outlets are provided in the upper portion of the casing, the furnace including a deecting wall impinged by the air after passing the ues and arranged to deflect the air upwardly toward the warm air outlets, a duct establishing communication between the warm' air outlet of the air jacket and an opening provided in said deilector wall, a baille over the last mentioned opening for deecting the air coming from the ues upwardly away from said opening, whereby to produce'a ships funnel effect to accelerate the circulation of air through the 4air jacket, and a power operated fan or the like in the cold air inlet opening of the air' jacket to further insure good circulation of air through said jacket.

17. In a furnace, the combination of a lire-box, a manifold, ilues establishing communication between the nre-box and manifold to conduct products of combustion from the, former to the latter, an enclosing casing for the aforesaid elements, the same being provided with one or more.

iiues for the admission of cold air and the discharge of warm air from the casing, oitake flues communicating with the manifold and disposed between the intake openings and the rst mentioned flues, and an air propeller disposed-between' the rst ues and the oitake flues in close proximity to the first iiues whereby to secure therefrom, all of said flues being of flattened the air coming from the ues upwardly awayy chamber on the other side of the hues, the inlet form and substantially streamline cross-section and disposed with the major axis of such section substantially parallel with the direction of air flow relative thereto, whereby to minimize restriction to air flow and insure better scrubbing action of the air on the surface of the fiues.

18. In a .hot blast type furnace, the combination of a casing having an inlet chamber with one or more cold air inlet openings and an outlet chamber with one or more warm air outlet openings, a heat radiator in said casing between said inlets and outlets, the same comprising a hre-box, a header manifold for discharging products of combustion from the furnace, and ues A for conducting products from the fire-box to the manifold, separate and independent passages in said casing for' conducting air from the inlet chamber to the outlet chamber, for heat.ab sorb-- the one hand, and

ingcontact with the ilues on with the fire-box on the other hand, air moving means for simultaneously causing air to ne circulated under pressure through said passages past the ues and past the fire-box to abstract heat therefrom-the warm air outlets in the outlet chamber being provided in the vupperportion thereof, a deflecting wall impinged by the air circulated past the flues and the air upwardly toward the warm air outlets, said deiiector wall having anv opening'provided therein communicating with the passage. con-l ducting the air past 'the fire-box, and a bae over the last mentioned opening for deiecting from said 'opening whereby to produce a ships funnel effect toiapcelerate the circulation of air past the fire-box. Y

19. In a hot'blast type furnace, the combination of a fire-box, a manifold, primary fiues establishing direct communication between the re-box and manifold to conduct products of y combustion from the former to the latter, an inlet chamber on one side of theiiues, an outlet chamber having one or more cold air inlets and the outlet chamber having one or more warm air' outlets, means for conducting the products of combustion from the manifold for discharge from the furnace, said means being disposed in the intake chamber in the path of air travel there-- through whereby to transfer residual Aheat from the products of combustion to the 'air for preheating, and an air propeller disposed downstream with -respect to said means in close proximity tothe first mentioned primary flues, whereby to cause direct impingement of the preheated air at high velocity upon the-primary exchange, and where- -ues for the principal heat by at the same time to secure circulation of air at lower velocity past the preheating means, the

' operation of said propeller resultingin increase in pressure in the outlet chamber for induced dissurface of the ues.

arranged todeflect amasar charge of warm air through the warm air outlets. A

20. In a hot blast type furnace, the combination of a nre-box, a manifold, ilues establishing communication between the re-box and manifold to conduct products of combustion from` the former to the latter, an inlet chamber on one side of theflues, an outlet chamber on'the otherside of the flues, the inlet chamber having one or more cold air inlets and the outlet chamber having one or more warm air outlets, means for conducting the products of combustion vfrom the manifold for discharge from the furnace, said means being disposed'in the intake chambervin the path of air travel therethrough whereby to transfer residual heat from the products of combustion to the air for preheating, and an air propeller disposed downstream with respectto said means in close proximity to the rst nientioned ilues, whereby to cause Vdirect impingement of the preheated airv at high velocity upon the ues for the principal heat exchange, and

major-axis of such section substantially parallel Y withthe direction of air flow relativethereto, whereby lto minimize krestriction to air ow and insure better scrubbing action of the air on theV `21. In afurnace, the combination of a fuel burner, an elongated nre-box therefor, an elongated manifold above the latter, substantially vertically disposed flues establishing 'communicationbetween-the-fire-boxnand manifold to conthe latter, a casing enclosing the aforesaid elements, a vertical wall on one side ofthe filles dividing the casing into an inlet and an outlet chamber, said wall having an opening therein, and an air propeller in the inlet chamber registering with said opening and disposed in close y proximity-to the nues, there being one or` more' openings provided in said casing for admitting vcold air to the inlet chamber in Vsaid, casing. and,V

lto cause air to impinge directly upon.the first ues for the principal heat transfer, and at the i sam'e time cause a reduction in pressure in the'v inlet chambenwhereby to draw in cold air past the offtake ilues, and create' pressure in theoutlet chamber whereby. to discharge warm air' unt der pressure.

' 22. In a furnace, the combination of a fire-box, amanifold, flues establishing Acon'imunication-between the fire-box and manifold to conduct prod= ucts of combustion from vthe formelto the lat-l ter, an'enclosing casing for the aforesaid elements, the same'being provided with one or nuireinlet and outlet openings on opposite sides of the flues for the admission of cold 'air and the discharge of warm air from the casing, oitake nues v communicating with the manifold and'. disposed between the-.intake openings and uie'nrsfimen-Y tioneii.V i'lues, and an air propeller disposed between the rst iiues and the offtake fiues in close proximity to the iirst ilues whereby to secure direct impingementof air at high velocity upon the iirst iiuesrfor a scrubbing action and eiectively transfer heat tozthe air from the products ofv combustion, and whereby at the same time to secure circulation of air at lower velocity about the oitake flues for preliminary heat surface ofthel flues.

transfer-therefrom, at least the rst mentioned iiues being of 'flattened form and substantially streamline cross-section and disposed with the major axis of such section substantially parallel with the directionof' air ow relative thereto, whereby Vto minimize restriction to air ilow and insure better 'scrubbing action or the air on the JAMES M. FUNK.