US2159440A

US2159440A - Sectional furnace

Info

Publication number: US2159440A
Application number: US101862A
Authority: US
Inventors: Allen P Livar
Original assignee: Reynolds Corp
Current assignee: Reynolds Corp
Priority date: 1936-09-21
Filing date: 1936-09-21
Publication date: 1939-05-23
Anticipated expiration: 1956-05-23

Description

May 23, 1939. A. P. LIVAR SECTIONAL FURNACE Filed Sept. 21, 1936 7 Sheets-Sheet 1 May 23, 1939. A. P. LIVAR 2,159,440

SECTIONAL FURNACE Filed Sept. 21, 1936 7 Sheets-Sheet 2 May 23, 1939. A. P. LIVAR 2,159,440

SECTIONAL FURNACE Filed Sept. 21, 1 936 7 Sheets-Sheet 3 May 23, 1939. A. P. LIVAR SEGTIONAL FURNACE Filed Sept. 21, 1936 7 Sheets-Sheet 4 Jllen Blz'var GMM y 1939- A. P. LWAR 2,159,440

SECTIONAL FURNACE v Filed Sept. 21, 1956 7 Sheets-Sheet 5 PM 427 126 a7 May 23, 1939. A. P. LIVAR SEOTIONAL FURNACE Filed Sept. 21, 1936 7 Sheets-Sheet 6 J27 |L a7 kl lll lr .ll/ezzflz'wr glen MM May 23, 1939. A. P. LIVAR I SECTIONAL FURNACE Filed Sept. 21, 1936 T Sheets-Sheet 7 3mm Allen flai /a1 Patented May 23, 1939 UNITED STATES PATENT OFFICE nolds Corporation, New York,

tion of Delaware Application September 21, 1930, Serial No. 101.882

lClaim.

This invention relates to air heating furnaces of the sectional type and is more particularly directed to an improved section structure.

Furnaces oi the general type to which this invention pertains have been used for the heating of air, and it is relatively common practice to form sections such that upon assembly of a plurality of similar parts there will be formed a continuous combustion chamber and a continuous flue defined by cooperating openings in each of the several parts of the iurnace together with a heat exchange region comprised by the hollow body portions of the sections. Such prior structures have been found to be poorly adapted for the construction of small, compact domestic air conditioning units since they were formed with heat exchange portions of considerable length in order to provide suflicient heat transfer area in the streams of air in the furnace.

These diillculties are obviated in the present invention by the provision of flat enclosed heat exchange portions in each of the sections. The sections are of unusual width, but it has been found that adequate contact of hot gases of com- 5 bustion with the interior surfaces of the section and eflicient heat transfer from the outer surface to the air to be heated is obtained by the prov sion of gas directing and heat exchanging fins.

The present invention therefore contemplates an improved section for such furnaces by means of which emcient heating is accomplished in a unit of novel and improved design.

The above and other objects which will be evident as the description proceeds, will be best understood by referring to the following detailed description and accompanying drawings forming a part thereof in which Figure 1 is a perspective view illustrating the system substantially in a typical installation within a conventional cellar of a dwelling house;

Figure 2 is an enlarged fragmentary perspective of the air conditioning unit, with the cabinet thereof being broken away for convenience to 4: illustrate the direction of air passage therein and the location of the air conditioning equipment with respect to the air passage;

. Figure 3 is a side elevation of a typical threesection assembly of heating unit constituting one typical embodiment of the invention as viewed from the left of Figure 2 and within the cabinet, one clean-out aperture closure being shown removed;

Figure 4 is a detailed view showing, in perspective, the construction of the closure plate for ballle clean-out aperture at the edge of each section;

Figure 5 is a fragmentary section taken on the line 5-4 of Figure 3;

Figure 6 is a longitudinal section taken on the line 8-6 of Figure 5;

Figure 7 is a transverse section taken on the line 1-1 of Figure 3;

Figure 8 is a view corresponding to Figure 7 and showing a modified arrangement of interior baflles;

Figure 9 is an exploded perspective view generally from the rear of the cabinet and illustrating the details of its construction and method of assembly; and

Figure 10 is a view on reduced scale illustrating a modification oi the cabinet appropriate for heating units of one or two sections therein,

1 wherein it will be observed that the rear of the heating unit is connected through the side oi the cabinet.

Referring to the drawings in detail, a typical installation of an air conditioning system embodying the invention is shown located in the cellar of any conventional dwelling adjacent an end wall ll thereof. It will be understood that the location shown is not essential, it being entirely practicable to locate the system as convenient in order to conform with architectural or other requirements. This system includes an air conditioning unit I! connected at one side thereoi to supply various portions of the structure with conditioned air through a conduit system l3. Conduit system I! comprises inter-connected conduit members rare-fabricated, under standardized mass production conditions, at the factory and assembled oi any desired combination of straight runs l4, curves I5, and fixed or variable split of! elements It communicating with any suitable passages il through the walls or flooring (not shown)' of the building. The conduit sections are specifically designed to provide the proper conducting capacity while enabling a maximum head clearance, in that the most capacious or deepest member extends not more than any desired distance, such as 8 inches, from the ceiling. Any suitable tie or bracket members (not shown) connected in the building structure may be employed for supporting the various portions of the conduit system. In its preferred embodiment the invention contemplates the air conditioning system to be of the re-circulatlng type in which case it will be observed that the conduit system includes any requisite arrangement of return conduit elements II, also prefabricated and standardized at the factory, and communicating with the opposite side of the air conditioning unit l2.

An. integral element of the air conditioning system is a cabinet I! (Fig. 2) communicating with the conduit system it. Cabinet II is preferably rectangular and is entirely pre-fabricated in that it can be readily assembled in situ or demounted by any workman. The plan of the cabinet is defined by a rectangular bottom frame member 20 including opposed side and end angle members 2| and subdivided approximately into halves by transverse angle member 22 welded therein. It will be understood that the angle members 2i and 22 are disposed with an upwardly extending edge so that the opposite surface coincides with the floor. Cabinet i8 includes opposed front and back walls or

plates

23 and 24 respectively, and opposed end plates 26 and 2B. These plates are composed of sheet metal and front and

back wall plates

23 and 24 rest upon the upwardly projecting edges of the bottom frame 20, the latter being received between corresponding angle closure members 21 and 2! comprising, respectively, the lower edge of said wall plates. Each wall plate is provided interiorly with a vertical channel 28 extending to the bottom thereof in which are engaged opposite edges of an intermediate partition 30 constituting a wall dividing the air conditioning unit into two substantially equal areas. The bottom edge of partition 30 fits in the transverse angle member 22 of the bottom frame and the upper edge is notched at opposite corners St to accommodate beads 32 at the top edges of

walls

22 and 24. The upper corners of front and

back walls

28 and 24 are rounded so that said top edges are closely engaged by a top plate 83 constituting a combined cover and duct support for the unit. The cover plate 33 is a substantially rectangular sheet metal member, the opposite ends of which are curved downwardly to present an ornamental appearance suggestive of stream lining, each end extending downwardly along the sides 01 the cabinet below the termination of the curvature to engage upper edges of

end plates

28 and 26.

End plates

25 and 26 extend vertically from the cover plate 33 to the floor, each including horizontal brackets M for supporting a pair of locking members 3!. Locking members 35 are pivoted in brackets 34 and operable from the exterior for looking or disengaging operation with respect to the end angle members of the bottom frame 20. It will be understood that the elements described are assembled to form a dust-proof and substantially air-tight casing when incorporated into the system with elements to be described hereinafter.

The cabinet described above constitutes a casing for a restricted U-shaped air conditioning area, a descending column of air entering via rectangular inlet aperture 35 and an exhaust column ascending therefrom through opposed aperture 31 cut in the cover plate 22. In order to provide communication in the air-conditioning area between the

apertures

26 and 31, a rectangular transverse aperture 28 is formed at the lower end of the partition 30. It will be evident that the descending column entering aperture 26 will pass downwardly through treatment chamber 2! tnerebeneath, pass through the transverse aperture 28 and move upwardly through heating chamber 40 on the opposite side of the partition and through exhaust aperture 31.

The dimensions of the casing may vary with the size of the installation; however, it will be observed that the construction described is one form capable of accommodating without essential modification a considerable variety of air conditioning accessories and respective capacities without necessitating alteration. For example, it will be observed by reference to Fig. 9 that the front and

back plates

23 and 24 may be utilized in many instances whether or not the width of

end plates

25 and 28 are modified and vice versa. The bottom frame 20 and cover plate 23 are perfectly adapted for utility regardless of the height of the installation. The entire assembly is composed of sheet metal and stiffening angle members, making for a light and attractive-appearing casing while at the same time affording convenient provision for rigidity, durability, and convenient handling in assembly and modification.

The system contemplates the provision of mechanically derived pressure for transmission of the air through the building, such pressure being obtained by operation of a blower ll mounted in the bottom of the treatment chamber 39. Blower II is of the cylindrical type, disposed for horizontal delivery through transverse aperture 38 and driven by any suitable type of noiseless motor 42. Both blower and motor are fixed on a horizontal support plate 43 resiliently supported on the fioor and maintained in proper location with respect to the treatment chamber 39 by spacing bars ll fixed in the frame 20. The motor I2 is equipped with cable It extending to any suitable outlet (not shown) for power supply. The fan or blower U is relatively large to provide ample pressure at low, quiet speed and by mounting it with motor 42 on the resiliently supported plate 43 any vibration incident to its operation is absorbed and prevented from being transmitted to the casing, ducts, or any other parts of the system.

The treatment chamber 39 receives the return air to be conditioned and is designed to include, in addition to the blower ll, filtering and refrigerating

apparatus

48 and 41, respectively. The filtering apparatus is preferably of the viscous type incorporated in a rectangular frame or tray ll and consisting of a porous layer of material such as metal shavings, glass wool, and the like, coated with a viscous substance such as oil held between layers of expanded metal (not shown). Important features of the invention include the disposition of the filter perpendicularly and substantially entirely across the U-shaped air stream and the inclusion in the cabinet structure of especially located and designed mountings which not only enable compact disposal in the cabinet but also the convenient removal of the filter ll upon occasion of periodic replacement or inspection. By disposing the filter entirely across the treatment chamber perpendicular to the U-shaped air stream initially upon its reception in the unit, full cleansing treatment is assured, thus obviating frequent cleaning of the other instrumentalitles of the system. The filter tray 48 is detachably mounted in the described relation on angle bars 49 preferably of metal which are secured horizontally across the walls of the chamber 39 below the plane of the cover plate 32. The angle bars are preferably welded or otherwise suitably aflixed to the stiffening angle members of the front and

back walls

23 and 24, and movement of the tray by sliding therealong is readily accomplished.

when the system is utilized for cooling, re-

irigerating apparatus 41 is placed in Refrigerating apparatus 1 consists of upper and lower-inter-oonnected ccoling'plates II comprising a cooling unit mounted in opposite sheet metal saddles II. The saddles II are indirectly supported by angle bars ll welded or otherwise suitably secured to the vertical frame members or the cabinet in order to permit horizontal sliding of the cooling plates during inspection and adjustment therein. It will be noticed that the angle bars I! and saddles II are disposed perpendicular to the descending column of filtered air and that they extend substantially entirely thereacross whereby maximum cooling is obtained. Angle bars 88 disposed immediately below and corresponding with angle bars I act as horizontal supports for a de-humidiiying tray ll, tray 64 being rectangular in shape to correspond with the cross-section of the descending column or air and having lateral saddles ll i'ast thereto for sliding engagement and support in angle bars II. The cooling plates iii are connected by cooling pipes ll; and an expansion valve II is interposed in pipe I communicating with any suitable source of liquid refrigerant (not shown) which maybe remotely located in any convenient position. It will be understood that by remotely locating the compressor. not only is the heat incident to its operation eliminated from the air conditioning system, but screening or concealment of the compressor is facilitated In employing the invention, an air cooled type of compressor aflords economical. efllcient, and silent operation. Horizontal angle spacing bar 50 isaflixed to suitable brackets ill to buttress the front and back plates 28 and 2! bearing the weight or the filtering, refrigerating, and de-hnmidiiying equipment suspended there- From the foregoing it will be observed that the descending column of airis entirely subjected successively to complete filtering, cooling, and dehumidii'ylng in treatment chamber 80 in order that the air propelled by blower ll will be completely air conditioned for re-circulation through the conduit system.

One of the more important aspects of the invention is the provision of a sectional heating unit ll, shown in detail in Figs.- 8 to 8, which may I be composed oi any desired number oi sections 82, each composed of corresponding cast half sections 83. Each halt section I includes a continuous rim it formed at the bottom to define the exterior of a fire box it and diverging therei above on each side to enclose a heat exchanger portion it. The lower portion or the casting is recessed at O1 to provide space for the the box I5 which extends longitudinally of the heating unit. The casting includes an integral transverse web portion 6! extending between opposite portions of rim Cl. Midway between the sides the upper portion of the casting is formed with a circular aperture I surrounded by an integral annular projection Ill, extending from web 68 i in a direction opposite the rim .4.

of two of the hall sections I assembled by buttwelding along the respective rims It to produce a list hollow body. the interior oi. which terms I a continuous passage connecting the firebox II and the circular aperture. I! constituting a passageway for hot gases of combustion originating in-the fire box. The interior face of each halt section 03 is formed with integral projecting baille plates llarrangedinthreedirections. The

Each section 0! the heating unit is composed lowermost group I! consists of a plurality extendingdiagonallyabovethefireboxrecessll. These diagonal baille plates constitute guides for directing the gases or combustion upwardly and divergentlyacross the expanse of the heat exchanger and in contact with a seoondgroup 01 plates II which are arranged in a plurality or horizontal rows one above the other individually and in staggered relationship to insure that the gases directed thereupon will be iorced through a highly tortuous path of a variable character thereby insuring retention of the gases in contact therewith tor a relatively long period of time to warrant maximum heat absorption therefrom.

Abovethe horizontal bank of belles It a plurality of bailles ll diagonally disposed further impede the progress 0! the hot gases of combustion toward the circular flue aperture es, thereby contributing in retaining the hot gases within the section until important heat thereot is entirely surrounded.

The annular projection II on the external lace oLeach halt section not only acts as an exhaust flue i'or gases but it projects beyond the web portion 8 and serves additionally as a spacing means for the adjacent heat exchange sections in the unit. 'Ihe lower portion oi the hall section includes an integral extended wall of continuous character which extends around the bottom 0! the fire box 65 and tapers inwardly thereabove to define the upper extent of combustion chamber II. It will be observed by reference to Figs. 3 and 6 that the wall 15 and annular projection Ill extend to the same vertical plane and cooperate in spacing adjacent heating sections of the unit with respect each to the other. Externally the web 68 is formed with a plurality oi integral heat exchange fins 11 disposed to project therelrom into the surrounding air stream. It will be observed that the fins 11 are especially designed and arranged to provide highly eflective heat exchange, in that they are wide and thin, terminating in a straight edge I8 and are disposed in stream lined alignment.- The web portions of the respective heat exchange sections are spaced each from the other by the projections III and 15 in order to permit circulation of air between the sections, and the fins I'I extend deeply into the air stream for maximum heat exchange due to radiation, convection, and conduction.

Projecting laterally on opposite sides of the wall 18 and at the top and bottom of the half sections 63 are corresponding lugs "bored to accommodate draw bars 80 for assembling the plurality of sections 82 toiorm a heating unit of the desired capacity. The sections are assembled in air-tight relationship to form a continuous heater, as shown irrFig. 6, the edges of annular projections Ill and walls It being tapered tor-reception with any asbestos gasket in continuous sealmg rings 8i and 82 disposed between adjacent projections I0 and walls It, respectlvely. V

The heating unit may be composed of any number of sections 82 depending upon the heat production and exchange capacity requisite to supply the requirements of the integrated system. Although the present disclosure in the main suggests an installation involving three sections 62 to form a heating unit. it should be understood that any number oi sections, for example, from one to live, may be assembled to correspond with the requirements of ordinary installations, and that the system disclosed readily may be integrated for utilization of more than five such sections.

when the three sections 02 have been assembled in sealing rings ti and I! the forward section 62 is provided with top and bottom closure plates II and I4, respectively. Top closure plate ll includes a flat disk with a peripheral flange 8i projecting on one face thereof. Flange," is formed with a continuous groove for receiving an asbestos gasket and the forward edge of fine projection 10. Bottom plate 84 is provided on one face with a peripheral grooved flange in which is received on an asbestos gasket the projecting wall I! of the immediate section II. The rearmost section 82 is provided at the top with a tubular fitting 81 for connection with a stack or other suitable flue exhaust (not shown), one edge thereof being formed with a continuous groove I! in which is received edge ll of the immediate section. A lower rear plate ll, also on suitable asbestos packing, is of standard design and includes a forwardly extending continuous rim it. The rim has a continuous groove ii in which is received the rearwardly extending wall IS of the section I. In order that the closure elements may be assembled in air-tight connection with the main section elements, the former are provided with integral lugs 92 bored to receive draw bars II. To insure a relatively rigid air-tight assembly of the heating unit, nuts I for tightening on draw bars 80 and SI seat on spring washers G5 in all connections whereby allowance is made for expansion and contraction due to temperature changes.

-'I'he rear closure plate ll constitutes a rearward extension for the combustion chamber and is designed for the reception of various of the fittings requisite for heating. For example. a recess ll serves as an observation opening, same being surrounded by a flange 01 for the reception of a door '8. Immediately below the observation opening a recess I! is provided which is adapted to be closed by a pivotally suspended mounting plate lill. Mounting plate llll is formed with a central recess ill for receiving draft tube I" of any suitable type of oil or gas burner Ill. Spaced between the front and rear closure plates of the unit by an envelope of as bestos flll llll topped in the usual manner with hearth cement III is flre pot lining III com posed of pre-cast refractory sections I", III. and ill. Front section III! is rectangular substantially to correspondwith the interior dimension of the cast portion 81 while the middle section is U-shaped and cemented as a spacer to connect the front section with rear section I". Rear section III is formed with a recess III in which is cemented the oil burner draft tube It! to position the burner in its proper location in the flre box I. By reference to Fig. 6 it will be noted that the flre box is assembled rearwardly of the median line of the heating unit in order to facilitate the even distribution of heat in the combustion chamber and over the flue baffles and compensate for the forward draft of the oil burner. Above the asbestos flll and fire box the combustion chamber extends from the front closure plate toward the rear closure plate to include a hinged heat deflector Ill pivotaily suspended from the top of the rear closure plate to prevent the rear closure plate from becoming heated. Hinged heat deflector Ill is formed with asight opening H2 in alignment with the observation opening II for permitting inspection of the combustion chamber therethrough during operation.

The heating unit described is spaced from the floor of the cabinet by vertical pipe legs Ill mounted in floor-engaging flanged disks ill, the

, upper ends ofsaid pipe legs receiving lugs Ill cast integrally on the lower surface of the heating sections. Spacing of the heating unit from the door is an important feature in that it enables the conditioned air blown from treatment chamber I! to pass thereunder in order that half heating unit closely, sumcient clearance being provided at the front and sides of the heating unit to enable flow of air thereacross; such spa/cing, however. being designed to maintain the air stream in relatively close contact with the exterior of the heating unit in order to promote heat exchange and derive compactness. The movement of the lower portion of the stream along the left side of the unit is directed by a curved guide plate ill fast to the wall of the cabinet and extending downwardly to engage the floor at the left of the heating unit.

The rear wall 24 of the cabinet is cut out as shown at Ill and Ill to enable it to fit over the flue exhaust fltting l1 and rear closure plate 89, respectively, of the unit, in order to save space and permit access in connection with the sight opening and burner without removal of the rear wall of the cabinet. Continuous packing rings I20 and III surround the recesses I III and 9 for maintaining the recess edges in air-tight connection with continuous asbestos gasket seals I22 and III, respectively, for preventing escape of air from the cabinet.

From the foregoing it will be observed that the air heated in the flre box I flows from the combustion chamber through the several hollow heater sections 62 and outwardly therefrom through the exhaust flttings '1. Very little heat, however, is lost in the fluegases due to their pro-' longed contact with the baiiles ll defining the tortuous es between the combustion chamher and the flue. By employing a silent type burner, the heating unit operates quietly; any slight noise being eflectively mumed by the enveloping cabinet. The conditioned air delivered through the transverse opening it proceeds along the successive elongated surface of the heat exchange flns which, being disposed in stream lined fashion, conform to the direction of flow of the stream for frequent and prolonged heating contact therewith without producing swirls or eddies and concomitant noise.

The curved guide plates within the heating chamber of the unit I 2 direct the air stream from the blower across the bottom of the unit and upwardly theretlirough to the supply conduit without swirls or pocket eddies at the angles of the cabinet, thereby eliminating an important source of ton noise.

Economical heating is a function of efficient heat exchange and relatively high exchange values are obtainable by suitable baflle arrangements which maintain the air to be heated in contact with the hot surface as long as possible.

2,100,440 5 Prior constructions, however, are frequently unposal within the combustion chamber beneath suited for incorporation in a modern air conditioning system in that, among other reasons. the requisite swirling of the air'and retention in contact with external projections produces eddy currents and additional friction load on the transmission system. This must be compensated for by increased fan speed and this. in turn, is productive of more objectionable noise. In the present invention, emcient heat exchange is obtained without noise by causing the hot gases of the combustion chamber to be propelled along .a highly tortuous path defined by the multiplicity of baiiles lying in staggered relationship inside of the heat exchange sections. This insures maximum absorption of the heat supplied, any resulting noise being confined within the cast iron heat exchanger and thereby effectively muflled. The air flows over the exterior of the heat exchangers without possibility of noisy swirling due to the stream lined disposition of the multiple extended heat exchange iins distributed over the exteriors thereof. The combination of the described internal battles and external stream lined fins. therefore, enables maximum heat exchange with a minimum load on the blower, thus insuring noiseless operation with economical heating.

Suitable apparatus (not shown) may be provlded, preferably in the top of the cabinet, for humidifying the heated air. Suitable controls (not shown) which form no essential part of the present invention are, of course, provided for the measured operation of the various instrumentalities in the system; The cabinet is provided with heads I" and I surrounding the supply and exhaust openings 36 and TI, respectively, in the top cover plate for-the convenient and closefltting reception of standardized terminal conduit sections 6 and I21, respectively, communicating with the opposite sides of the conduit system.

An alternative form of heat exchanger construction is shown in Figl B. Therein the integral cast baffles H on the half section 58 are arranged much more closely together and in greater number than in the embodiment shown in Fig. I. This usage is preferable under certain conditions, as for instance in gas firing, in order to compensate for greater tendency for slippage and Y loss incldent'to such method of heating. It will, however, be observed that the design of the individual baiiles and the plan of distribution in the sections, as in the former case, is contrived to promote extremely high heat exchange through requiring passage of the hot gases of combustion through a tortuous path before permitting egress through the flue fitting I1.

The attractiveness, compactness, and efilciency of the air conditioning unit described may be obtained without sacrifice -of any desirable household equipment: for example, the sectional heating unit and enveloping cabinet are adapted to accommodate any suitable type of hot water coil I28 leading to a storage tank (not shown). The coil I28 is mounted by recessing the rear cover plate 89 at I29. and hinged heat deflector III at I80. Any suitable fitting Ill rigidly mounts the coilon the rear cover plate so that it extends across the upper portion of the combustion chamber to receive maximum heating eflect from the hot gases therein.

Mounting the heating coil directly through the rear cover-plate obviates interference with the flow of conditioned air between the cabinet and heat exchange surfaces of the unit; and its disthe balls passages thereof enhances the impeding effect on the gases of combustion and assisting in prolonging their-contact with the heat absorbing baiilel.

Fig. 10 discloses an assembly illustrating the adaptability and elasticity of the integrated standardised sectional air conditioning system disclosed. Therein will be observed the organization of the air conditioner and cablnetwhen the heating unit is composed of less than three sections. For example, if two sections constitute the heating unit they may be positioned to extend. transversely of the heating side, so that the heater front faces the central, the rear cover plate and rear appliance fittings extending laterally toward the left. In the specific embodiment presented, apertures I" and I" are formed in side plate I" for the reception of an exhaust fitting I35 and rear cover plate I",

suitable finishing rings I31 and I88, respectively,

being attached thereto for preventing escape of the conditioned air therefrom. In this relation the other half of the cabinet may be equipped with the requisite complement of air conditioning instrumentalities described. Connection in the conduits for recirculation and re-conditioning of the air is eflectuated, as in the manner described above, through opposite inlet and exhaust apertures "land Mil, respectively.

Regardless of the size of the installation and the consequent number of sections constituting the heating unit, the constructions described are especially designed to obviate any necessity for dismantling the cabinet and contents during the life of the burner. As pointed out above, accumulation of dust within the cabinet is prevented by iiltering the air stream immediately upon its entrance. when the pre-fabricated cabinet is assembled in situ, the various elements thereof are connected to preclude entrance of dust at any of the joints.

" the clean out aperture ill during heating operation. Cleaning the interior of the heating section requires merely the temporary removal of cabinet end plate 26 and removal of the closure plate I, both plates being easily removed and replaced without interfering with other portions of the apparatus.

I claim:

An air heating furnace having means defining an enclosed air heating space, means to admit cold airv to said space, means to direct heated air from said space and a heating unit within said space, said unit comprising a plurality of similar sections each formed to define a combustion chamber portion, a flue portion above said combustion chamber portion and an outwardly flared hollow means defining a continuous enclosed space of substantially greater width than the combustion chamber portion communicating with each of said portions. said hollow means being defined by parallel side walls of a width substantially greater than the width of ltantiniiy wider than the combustion chamber portion. said sections bein: connected in sideby-side relationship. integral air directing means projecting from the external suriace oi each of 1c saidsectionsarran edtopromotecontsetoiair mm No. 2,159,Lmo.

ALLEN P. It is hereby certified that error appears of-the above numbered patent requiring correction as follows: 0nd column, line 21 for the word "surrounded" to be heated with the whole oi said external surface and direct said air toward the lower side of said flue portion and integral gas directing means projecting from the internal suri'ace oi each 01' said sections arranged to, promote contact of combustion gases from said combustion chamber'portion with the whole of said internal surface in the flow of said gases from said combustion chamber portion to said flue portion.

ALLEN P. LIVAR.

CERTIFICATE OF CORRECTION;

my 2 19 9. LIVAR.

in the printed specification e 3. read surrendered; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 25th day of July, A. Di 1959.

(Seal) Henry Van Arsdnle, Acting Commissioner of Patents.

' ltantiniiy wider than the combustion chamber portion. said sections bein: connected in sideby-side relationship. integral air directing means projecting from the external suriace oi each of 1c saidsectionsarran edtopromotecontsetoiair mm No. 2,159,Lmo.

ALLEN P. LIVAR.

CERTIFICATE OF CORRECTION;

my 2 19 9. LIVAR.

Signed and sealed this 25th day of July, A. Di 1959.

(Seal) Henry Van Arsdnle, Acting Commissioner of Patents.