US2035993A - Air heating chamber for heat generators - Google Patents

Description

March 31, 1936.

Filed July 2, 1932 2 Sheets-$heet l INVENTOR Jerome I S loyan ORNEYS IBY/ March 31, 1936. J. J. SLOYAN AIR HEATING CHAMBER FOR HEAT GENERATORS Filed July2, 1932 2 Sheets-Sheet 2 f a; r.

INVENTOR Je'mme J Sloyan a 1. Mm & ORNEYS .PatenteclrMar. 31, 1935 UNITED STATES PATENT OFFICE AIR HEATING CHAIWBER FOR HEAT GENERATORS Jerome J. Sloyan, Red Bank, N. J.

Application July 2, 1932, Serial No. 620,595

4 Claims. (Cl. 15828) This invention pertains generally to heat gen- Figure 6 is an elevation partly in section of erators and particularly to air heating chambers another form of air heating chamber. therefor. Referring more particularly to Figures 1, 2 and The invention pertains more particularly to a 3, at In is shown for purposes of illustration a construction in which the heat of combustion is heat generator assembly comprising an air heatemployed for air preheating purposes, the preing chamber I I, ahomogenizing heating chamber heated air being used for supplying heat to form l2, a conduit l3 having an opening I4 for the a homogeneous mixture of air and fuel and for insertion of a thermostatic switching device if supplying oxygen to the mixture to support the desired, a preliminary air heating chamber I5 combustion thereof. for starting purposes, a second opening l6 down- 10 It is desirable in many instances to form an air stream from the chamber l5 for the insertion heating chamber about a portion of the combusof a second thermostatic switching device if detion chamber for the purpose of preheating air. sired, a conduit l1 leading to the air inlet of The air upon flowing through the air heating carburetor IS, an outlet [9 for carburetor l8 leadchamber absorbs sufficient heat from the coming into a combustible mixture homogenizing bustion chamber to materially assist in mixing chamber which receives heat from chamber l2, it with fuel to form a combustible mixture and a. venturi 2| to prevent backfire, electrodes illusin holding the fuel in a vaporized condition prior trated at 22 for initial ignition, and a combustion to ignition thereof. As pointed out in my cochamber of which the tapered portion shown at 20 pending applications, Serial Nos. 620,592, 620,593 23, hereinafter referred to as the ante-combustion 20 and 620,594, relating to Air passage for heat chamber, is a part. The details of construction generator, Control for heat generator and of the burner illustrated are more particularly 'Heat generator, filed July 2, 1932, this will genreferred to in my above mentioned copending erally require a high rate of heat transfer beapplications.

25 tween the combustion chamber and the air heat- In my copending application, Serial No. 620,594 25 ing chamber for which highly refractory matefor Heat generator, filed July 2, 1932, I have rial is ordinarily not suitably adapted. Inasmuch described and claimed a heat generator assemas the temperature of combustion is sufiiciently bly in which the draft is induced, for instance, high to ordinarily prove destructive to a metallic by a blower placed in the stack. In such an asdividing surface special means for holding a mesembly the air employed for supporting combus- 30 tallic dividing surface at a safe temperature is tion is drawn through the air heating chamber highly desirable. If heat transfer from the diby suction or, in other words, is forced through 'Viding metallic wall to the air flowing through by atmospheric pressure. In order to ensure a the air heating chamber may take place unihigh rate of air flow over the entire outer surface 5 formly over the entire air contacting surface of of the metallic dividing wall or housing 24 bethe dividing wall and at a rate comparable to tween ante-combustion chamber 23 and air heatthe rate of heat transfer from the gases of coming chamber I I, I confine the air in air heating bustion to the dividing wall, the dividing wall may chamber l I to a special path. The path is formed be held at a temperature well below one at which by providing a sheath 25 about the housing 24 40 it would rapidly deteriorate. and by providing a specially formed inlet 26 for 40 This invention is directed to air heating chamthe air heating chamber ll thus formed.

bers of the above type and more particularly to The inlet 26 is positioned adjacent one end details of construction, the arrangement and of the housing 24 so that the air will flow over combination of parts, all of which will more fully the full length of the outer surface thereof. In

'45 appear upon reference to the dr'awings,'in which order to insure that this flow of air will be dis- Figure 1 is a sectional elevation of a heat gentributed more or less uniformly circumferentially rat y s m s w f r th purp ses of illusof the housing 24, I construct the inlet 26 cirtration; cumferentially about the end of housing 24.

F u 2 i an elevation o t e a heating In the form shown in Figures 1 to 3 inclusive chamber shown in Figure 1; inlet 26 is formed by a circumferential row of 50 Figure 3 is a Section 011 line of Figure longitudinally arranged slots 21 more or less Figure 4 is an elevation partly in section of closely spaced and preferably although not necesanother form of air heating chamber; sarily uniformly spaced and of uniform dimen- Figure 5 is an elevation partly in section of sions.

-.- a further form of air heating chamber; and Housing 24 may have any other shape. The 55 conical form shown which might be varied soas to include a tulip shape or a morning glory shape, that is, a shape resulting from the revolution of a curved line instead of a straight line, is specially adapted for the type of heat generator illustrated as will more fully appear in the above mentioned copending applications. The invention, however, is not limited thereto.

It will be noted that the spacing between sheath 25 and housing 24 increases from left to right in Figure '1, the purpose of which is to provide as nearly as practicable a uniform cross-sectional area for the chamber 1 l throughout the length thereof. Such an arrangement provides for substantial uniformity of velocity of air flow over substantially the entire area of the outer surface of the housing 24. Inasmuch as heat transfer is a function of surface velocity, such an arrangement closely approaches the desideratum of uniform temperature throughout the housing 24. Uniformity of temperature throughout the housing 28 is inconsistent with the existence of hot spots at which deterioration might .take place.

It will be understood that the rate of air flow increases with the rate of combustion.

With the type of heat generator shown at 18 the base of flame travels outwardly to the left in ante-combustion chamber 23 after a certain rate of combustion is reached, the base of flame being automatically located in a plane at which the velocity of incoming fuel mixture is equal to the velocity of flame propagation, it being understood that the velocity of incoming fuel mixture decreases from right to left in Figure 1 as the cross-sectional area of ante-combustion chamber 23 increases. The result is that somewhere between minimum and maximum operation the temperature of the air reaches a peak which withproper design is well within'safe operating temperatures, from which peak point the temperature of the air decreases at a relatively slow rate as the rate of combustion proceeds toward maximum. This operation is more fully explained in my copending application, Serial No. 620,592, for Air passage for heat generator, flled July 2, 1932, above referred to. Any means may be employed for spacing the sheath 25 about the housing 24. In the form shown I have provided a spacing ring 29 between the adjacent ends of housing 24 and sheath 25 and have employed a wedge ring 38 which is forced outwardly over the larger end of sheath 25 to force the parts together. The parts may then be secured in place, as by welding.

Sheath 25 fits at the other end within an opening 3| in chamber 12 arid a tight joint is provided by means of a packing nut 32 and a gasket 33. Ante-combustion chamber 23: is shown formed integral with the homogenizing chamber 25, the end 34 of which is secured to the end Wall 35 of chamber I 2, as by welding. The filler 36 is provided to approach uniformity in cross-sectional area of the chamber II as above referred to.

.In order to attach the air heating chamber structure to the furnace or other wall illustrated at 31, I have provided a plurality of spaced hollow lugs 38, each of which has an end 39 which abuts ring 38 and a circumferential edge 48 secured to'the outer surface of sheath 25 such as by welding. Lugs 38 afford a means for engagement by a set of spaced clamps, each comprising a stud 4 I. and a lug 42.

It is, of course, understood that any other structure may be provided for this purpose.

Inasmuch as lugs 38 will be positioned over certain of the slots 21, lugs 38 in the form of a series of hoods provided with slots 44 to permit the inflow of air to the slots 21 therebeneath. The slots 44 are preferably positioned as shown so that the infiowing air will contact the portion of the outer surface of sheath 25 falling beneath each lug 38 to prevent overheating of such portion.

If wall 31 is provided with a circumferential groove 46, a gasket 41 may be placed at the bottom of the groove and may be contacted by the end of the air heating chamber structure in a manner so that the flames of combustion cannot reach the gasket to burn it out.

Another form of the invention is shown in Figure 4 which is in all respects similar to that shown in Figures 1 to 3 inclusive except that the air heating chamber inlet 26 is formed by slots 50 having their circumferential dimension or dimensions larger than their dimension or dimensions longitudinally of the sheath 25. The slots 5| in lugs or hoods 52 may be arranged longitudinally of the lugs 52 as illustrated in Figure 4.

In the form of the invention shown in Figure 5 the lugs shown at 38 and 52 are substituted by a single enveloping hood 53 having a continuous circumferential peripheral wall 54 and an end wall 56. Wall 54 contacts the circumferential side edge of wedge ring 38 and may be made integral therewith. Side wall 56 has an inner circumferential edge 51 in contact with the sheath 25. An inlet chamber 58 between the hood 53 and the outer surface of sheath 25 is thus formed. Inlet 26 to air heating'chamber l I may be formed with any character of opening, for instance'the longitudinal type shown at 21 or the transverse type shown at 58.

The inlet 59 to chamber 58 comprises a circumferential row or rows of openings 60, preferably though not necessarily positioned in hood 53 at a maximum distance from the inlet 26 so that air passing into chamber 58 will have a maximum contact with that portion of the outer surface of sheath 25 which falls beneath the hood 53. Such an arrangement will avoid any possibility of overheating of that portion of sheath 25 which is covered by the hood 53.

'It will be noted that the forms of the invention shown in Figures 1 to 5 inclusive are specially adapted for the induced draft type of heat generator wherein the air is drawn through the air heating chamber by means of suction.

The form of the invention shown in Figure '6 is adapted for both the induced draft type and the forced draft type of heat generator. The construction is in all respects similar to that shown in Figure 5 except that the inlet 59 into chamber 58 comprising a circumferential 'row of openings 68 is substituted by a single opening 6| over which is positioned a pipe 62 which is open to the atmosphere when used with the induced draft type of heat generator and is connected to a blower (not shown) when used with the forced draft type of heat generator.

In the form shown in Figure 6 it will be noted that the wedge ring 30 is made integral with the end 55 of hood 53. Such an arrangement or its equivalent might be substituted in Figure 5.

The parts may be secured together by any suitable means. I have found that welding in most instances is very satisfactory. However, any other means accessible to persons skilled in th art may be employed.

The parts described in detail may have other shapes than those shown and may be constructed in other ways. The detailed description is by way of illustration.

Having described my invention, it is obvious that many modifications may be made in the same within the scope of the claims without departing from the spirit thereof.

I claim:

1. In a fuel burner having in combination a housing forming a combustion chamber, means including a carbureting device for discharging a combustible mixture into one end thereof, said housing having walls that diverge from said end of said chamber, a sheath arranged in spaced relation about said housing and forming therewith an air preheating passage of approximately uniform cross-sectional area throughout the major portion of its length and which communicates at one end with the carbureting device, said sheath being open substantially throughout its circumference admitting air directly into the outer end of said passage and at an angle with respect to the length of said passage, and a hood arranged about said sheath in spaced relation therewith providing an inlet and a passage for air to said sheath.

2. In a fuel burner having in combination a housing forming a combustion chamber, means including a carbureting device for discharging a combustible mixture into one end thereof, said housing having walls that diverge from said end of said chamber, a sheath arranged in spaced relation about said housing and forming therewith an air preheating passage of approximately uniform cross-sectional area throughout the major portion of its length and which communicates at one end with the carbureting device, said sheath having a plurality of openings at spaced points substantially throughout its circumference admitting air directly into the other end of said passage and at an angle with respect to the length of said passage, said sheath being secured to said housing at its larger end and solely supported thereby.

3. In a fuel burner having in combination a housing forming a combustion chamber, means including a carbureting device for discharging a. combustible mixture into one end thereof, said housing having walls that diverge from said end of said chamber, a sheath arranged about and extending substantially the length of said combustion chamber in spaced relation to the walls thereof for forming an air passage between the sheath and the walls of the combustion chamber, an open hood admitting air thereinto, said hood being arranged annularly in spaced relation about the larger end of said sheath and extending partially over the length thereof and forming with said sheath a second air passage, said sheath having an opening adjacent said larger end thereof for providing a means for communication between said two air passages.

4. In a burner, in combination a housing forming a combustion chamber, said housing having diverging walls, an open hood admitting air thereinto, said hood being arranged about the larger end portion of said housing and joined to said housing at said larger end of said housing and free from connection to the other end of said housing and extending over said combustion chamber for part of its length, a sheath arranged about said combustion chamber housing and extending longitudinally of said housing, said sheath surrounding the part of the housing that is outside of said hood and also extending longitudinally in spaced relation to the walls of said combustion chamber in the other direction into the space formed between said hood and said housing forming substantially two separate air passages in said space, one air passage being between the hood and the sheath and the other air passage being between the sheath and said combustion chamber housing, said two air passages communicating with each other.

JEROME J. SLOYAN.

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