US2616412A - Fuel burning air and liquid heater - Google Patents

Description

Nov. 4, 1952l c. M. BACKUS 2,616,412

FUEL BURNING AIR AND LIQUID HEATER Filed Jan. 31, 1948 Patented Nov. 4, 1952 AUNITED STATES PATENT OFFICE FUEL BURNING AIR AND LIQUID HEATER Charles M. Backus, Burbank, Calif.

Application January 31, 1948, Serial No. 5,541

My invention relates in general to heaters and, more particularly, to a heater of the type in which heat is transferred from one fluid to another, a primary object of the invention being to provide a heater .having an improved heat exchanging means.

' More specifically, the invention is directed to a, heater'having one or more substantially vertical coils of tubing through which a fluid to be heated may flow. f

` A further object is to provide a heater which includes a substantially vertical ue positioned above and extending upwardly from a burner, which includes concentric inner and outer coils encircling the flue and adapted to convey the fluid to be heated, and which includes a hood over the coils and the flue, the hood being adapted to deect products of combustion ilowing upwardly through the flue from the burner outwardly and downwardly so as to form an annular stream which flows downwardly between the flue and the hood in contact with the'coils. Still another object is to provide a heater wherein the hood,v coils, and flue are encircled by acasing which cooperates with the hood to provide an annular spacev communicating with the space between the hood and the flue so that the products of combustion may flow upwardly through this annular space after flowing downwardly past the coils. v

important objectof the invention is to provide a heater wherein the inner coil contacts the flue and wherein the outer coil contacts the hood so that heat may be transferred from the products of combustion flowing upwardly through the ueto the fluid in the inner coil by conduction through the walls of the ue, and may be transferred from the products of combustion owing upwardly through the annular space between the casing and the hood to the fluid in the outer coil by conduction through the walls of the hood. Another important object in this connection is to provide a heater wherein .the coils are iiattened to provide large areas of contact with the walls of the flue and the hood. This construction permits a considerable quantity of heat to be transferred from the products of combustion to the uid in the inner and outer coils by conduction through the walls of the flue and `the hood, which is an important feature ofthe invention.

3 Claims. (Cl. 126-101) Another object is to provide a heater having means for transferring heat to a stream of air flowing through the heater. A related object is to provide a heater having an outer hood which is spaced from the casing to provide a chamber through which air to be heated may be circulated.

Another important object of the invention is to provide a device which, in addition to being capable of heating a iluid flowing through the coils, is also adapted to be used to cool a uid owing therethrough. l

The foregoing objects of thev invention and the advantages suggested thereby, together with various other objects and advantages which will become evident, may be attained through the utilization of the exemplary embodiment which is illustrated in the accompanying drawing and which is described in detail hereinafter. Referring to the drawing:

Fig. 1 is a utility view showing an applica-v tion of a heater which embodies the invention to the cooling system of an automobile engine.

Fig. 2 is a vertical sectional view of the heater;

Fig. 3 is a vertical sectional View of the heater which is taken along the broken line 3-3 of Fig. 2; and

Fig. 4 is a transverse sectional view which is taken along the broken line 4-4 ofFlg. 2 of the drawing.

The heater of my invention, indicated generally in the drawing by the numeral lll, is susceptible of various applications, one of these being illustrated in Fig. 1 wherein I show the heater connected to the cooling system Il of an automobile engine l'2 for purposes of illustration, the heater being mounted on the re wall I3 of the automobile in which the engine is mounted. In the particular installation illustrated in Fig. 1 of the drawing, one of the functions of the heater IB is to maintain the water or other fluid in the cooling system Il at or near operating temperature so as to eliminate anyy necessity for preliminary warm-up of the engine after starting same. However, the heater I0 may be employed for other purposes, such as maintaining the oil of an aircraft engine at or near operating temperature, and it will be understood that I do not intend to be limited to the specic application illustrated in the draw-,-

Considering the heater Iil in more detail, it includes a vertical, substantially cylindrical casing I5 having an upper end wall I6 and a peripheral wall I1, the lower end of the casing being closed by a base I8 having an annular flange I9 which telescopes over the casing. Disposed within the casing I5 is a burner 22 which is mounted on a cup-shaped bracket 23 carried by the base I8, the burner being supplied with fuel, such as gas or gasoline, through a fuel line 24. The burner 22 per se forms no part of the present invention and, since any suitable burner may be employed, it is not shown and described in detail.

A member forming an annular chamber 25 having an upper wall 26 and inner and outer walls 21 and 28 is carried by the base I8 and encirclesthe burner 22, the inner wall 21 preferably being sealed with respect to the burner, and the inner and outer walls 21 and 28 p'rer^ erably being sealed with respect to the base, as by welding annular flanges'ZS at the vlower ends of the inner and outer walls to the base. It will be noted that the inner wall 21 of the annular chamber 25 and the cup-shaped bracket 23 cooperate to dene an annular space3, combustion air being supplied to the burner 22 through 'the annular'space 30 and chamber 25 by way of openings 3I inthe base I3, openings 32 in the inner wall 21 of the chamber and openings 33 in the upper wall 25 of the chamber, as indicated by the arrows 34. With this construction, in the event of a flash-back from the burner 22, any flames are extinguished either in the annular chamber 25, or in the annular spa'ce 35 between the cup-shaped, bracket 23 and the chamber 25, so that 'no llame can escape from the casing I5, which is an important lfeature of *the invention.

Gases produced by combustion of the fuel supplied to the burner 22 ow upwardly from the burner through a flue 3B, as indicated by the arrows 39, the combustion zone extending upwardly into the flue so that the latter may be regarded as a combustion chamber for the fuel Vsupplied to the burner. The ilueY 38 includes a lower, upwardly converging, truste-conical portion 40 and an upper, cylindrical portionI. The flue 38 is centrally located within the casing I5 and is mounted on an annular shroud 42 which extends inwardly from the peripheralwall l1 f the casing, the shroud `terminating "in an upwardly converging, frusto-conical flange 43 which extends into the frusto-conical portion 40 of the ilue, the flue being secured to the shroud by rivets 44 or the like. The shroud 42 provides a seal between the casing I and the Vflue 38 so that all of the products of combustion emanating from the burner 22 flow upwardly through the flue.

Disposed within the casing I5 over the flue 38 is a hood 41 having an upper end wall 48 which is spaced from the upper end of the flue and which is suitably secured to the upper end wall I5 of the casing, as by spot welding for example. The hood 41 is provided with a downwardly extending peripheral wall 49 which terminates above the shroud 42 and which divides the space between the peripheral wall I1 of the casing I5 and the ue 38 into annular spaces 5I and 52. Secured to the upper end Wall 48 of the hood 41 is a generally 'conical baille 53 which is aligned with the flue 38 and is spaced from the upper end thereof, the baille 'being adapted to direct the products of combustion owing upwardly through the flue outwardly and downwardly into the annular space 5I in the form of an annular stream, as indicated by the arrows 54. Subsequently, the products of combustion flow from the annular space 5I into the annular space 52 and ow upwardly through the latter into an exhaust tube 55 connected to the casing I5, as indicated by the arrows 56. A suitable exhaust line (not shown) connected to the outlet 55 may be employed to convey the products of combustion to a suitable point of disposal, such as the exterior of an automobile, for example, in which the heater I5 may be installed. .I t A t 'Concentricy substantially vertical inner and outer coils 6I and 62 are disposed in the annular space 5I between the flue 38 and the peripheral wall 49 of the hood 41, each coil comprising a helical tube through which water from the cooling system I I, for example, may flow. The lower ends of the helical tubes forming the coils BI and B2 are interconnected, as by a manifold 63, and the upper. ends thereof are similarly interconnected, as by a manifold 64, the lower ends of the helical tubes being connected to an inlet tube 65 which Ais threaded into the Amanifold 63, and the upper ends 'thereof being' connected to an outlet `tube 66 which is threaded into the manifold 64, all as best shown in v2rofftl`1e drawing. As indicated in Fig: 1 of theidrvawing, the heater may be connected 'in' 'thecooling 'system II, for example, ,by lines61 andf68`cone'cted to the inlet 55 and outlet 66, respectively., How.- ever, it will be understood that the invention'is susceptible of various other applications 'as hereinbefore discussed. ,t

As best shown in Fig. 3, of the drawing, 'the inner coil 6I contacts the flue"38 so that Asome heat' may be transferred from the products of combustion owing upwardly ,through 'the'fle to the water or other lfluid in the inner coil by conduction through the walls of thefluveand the tube forming the inner coil. Similarly,the outer coil 62 contacts theA peripheral wall4 '49 of the hood 41 so that some heat from the products of combustion flowing upwardly through the an? nular space 52 maybe transferred to'thewater or other uid in the `outer, 'coil ,by conduction. In order to increase the quantity of heat transferred to the water or other fluid by conduction in this manner, theY tubes forming the inner and outer t coils 6I and 62 are p'refeiablyv flattened, as indicated lby the numerals 4mand 1I. 're-spec#- tively, to increase the areals'ofjconta'ct 'between the inner coil and the flue 38 andl betwenl'the outer coil and the hood 41, which is'an important feature of the invention. I y t o,

Considering the operation of the yheater Illas thus far described, fuel, suchl as gasolinefmay be admitted to the burner 2 2 by opening a valve 12 interposed between the fuel' line 2,4 andthe burner and may be ignited by energizing a suitable spark-producing device 13, as is well known in the art. Air for the combustion of the fuel supplied to the bur-ner 2,2 flows through the ane nular 'space 33 between the cup-shaped bracket 23 and the annular chamber 25 and through the annular chamber 25, as indicated by the-arrows 34, the annular space 33 and'chamberV 25 preventing any flash-back as Vpreviously discussed. Preferably, the areas of the openings 3'Ij4 32 and 33 'through which the ai-r supplied toV theburnfer flows are such that anV excess off'co'ribustion'air is suppl'ied'to the burner toinsure 'cqnipltecombustion of the fuel as is well'iftheart.

The products of.v4 combustionemanating from the burner 22l flows upwardly through the flue 38 and'become thoroughly mixed with any lexcess air supplied to the burner so that, by the time the products of` combustion reach the upper end of the flue, the temperature thereof is substantially uniform. It will be noted that the flue 38 prevents. the products of combustion from coming in contact with the coils 6I and 62 until such uniform temperature is attained, thus preventing local overheating of the coils, which is an important feature of the invention.- As previously discussed, some of the heat contained in the productsA of combustion owing upwardly through the flue 38 is transferred to the water or other fluid in the inner coil 6I by conduction, the tube forming the inner coil being flattened to increase the quantity of heat transferred in this manner.

As the products of combustion reach the upper end of the flue 38, they are directed downwardly and outwardly by the baie 53 and flow downwardly through the annular space 5I in contact with the coils 6I and l62, additional quantities of heat being transferred from the products of combustion to the fluid in the coils by conduction through the walls of the tubes forming the coils. Subsequently, the products of combustion ow from the annular space 5l into the space 52 and flow upwardly through the latter to the exhaust tube 55, as indicated by the arrows 55. As previously discussed, an exhaust line (not shown) leading to a suitable point of disposal may be connected to the exhaust tube 55.

As heat is transferred to the fluid in the coils 6I and 62 in this manner, the iiuid therein circulates upwardly through the coils by convection. Thus, a countercurrent relationship between the direction of flow of the fluid through the coils '6I and 62 and the direction of ow of the products of combustion contacting the coils obtains, which is an important feature of the invention.

In the particular application of the invention illustrated in the drawing, water from the cooling system II flows by convection through the line 6'I to the heater and returns to the cooling system through the line 68. It will be understood that the water in the cooling system `II may be maintained at any desired temperature by regulating the amount of fuel supplied to the burner 22. When the engine I2 is started, the heat produced thereby normally will maintain the temperature of the water in the cooling systern II at the proper operating level and the burner 22 may be extinguished.

As previously discussed, an important feature of the invention is to provide a heater which, in addition to maintaining the temperature of a fluid, such as the water in the cooling system I I, at a predetermined value, is also adapted to supply heated air which may be used for heating the passenger compartment of an automobile, for windshield defrosting, etc. As best shown in Figs. 2 and 3 of the drawing, the heater I0 includes an outer casing I5 which is connected to the casing I5 by bolts 1G, the outer casing being spaced from the casing I5 and being sealed with respect thereto. The outer casing 'I5 is provided with an inlet duct I1 having therein a motor 'I8 which is adapted to drive a fan 19, and is provided with outlet tubes 80 and 8| to which ducts (not shown) leading to points where heated air is desired may be connected. For example, a duct terminating in the passenger compartment of an automobile may be connected to the outlet tube 80 and a duct leading to a windshield adapted to heat the fluid circulating through the coils 6I and 62, which is an important feature of the invention.

As best shown in Figs. 3 and 4 of the drawing, the peripheral wall I1 of the inner casing l5 and the peripheral wall 49 of the hood 4'1 are provided with openings 84 and 85, respectively, which are aligned with the inlet duct 11, the openings 84 and 85 normally being closed by curved shutters 86 and 81 which are movable in suitable tracks 88 and which may be opened manually by a handle 89 connected thereto. It will be apparent that when the shutters and 8I are opened, the fan 'I9 may be employed to circulate air through the annular space 5I containing the coils 6I and 62, such air escaping through the exhaust tube 55. This feature of the invention is important in that it permits the fan 'I9 to be used to circulate air for reducing the temperature of the water or other iiuid in the coils 6| and 62 to reduce the temperature of the cooling system II, for example, if' the engine I2 tends to overheat in hot weather. Since the air heated in this manner escapes through the exhaust tube 55, which, as previously discussed, may be connected to a suitable point of disposal, it is not discharged into the interior of the automobile.

Although I have disclosed an exemplary embodiment of my invention and have described a specific application thereof for purposes of il lustration, it will be understood that I do not intend to be limited thereto since the invention is susceptible of various other applications and since various changes, modifications and substitutions may be incorporated in the exemplary embodiment disclosed, all without necessarily departing from the spirit of the invention. Consequently, I hereby reserve the right to the protection afforded by the full scope of the appended claims.

I claim as my invention:

1. In a heater, the combination of: a burner; a substantially vertical iiue positioned above and extending upwardly from said burner; a substantially vertical coil comprising a helical tube which encircles said flue, said tube having an inlet at one end for a fluid to be heated and having an outlet at its other end for heated fluid; a hood over said flue and said coil, said hood comprising an end wall which is spaced from the upper end of said flue and comprising a downwardly extending peripheral wall which encircles said coil and said ilue; an inner casing enclosing said hood and having a peripheral wall which is concentric with and spaced from said peripheral wall of said hood, said inner casing being provided with an outlet adjacent its upper end which communicates with the space between said peripheral walls; and an outer casing over said inner casing, said outer casing being spaced from said inner casing and being provided with an inlet and an outlet which communicate with the space between said casings.

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eralwu''f sid'in'er casing are provid-ed*y with im@ d thispatem:

M, BAGKUS, 507,113 f Marshall May '9:1950

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