US2361097A - Heating apparatus - Google Patents

Description

Oct. 24, 1944. Q H 2,361,097

HEATING APPARATUS Filed March ll, 1941 INVENTOR E'Ffazmc 0. H555 51W ATTORNEY Patented Oct. 24, 1944 HEATING APPARATUS Frederico. Hess, Germantown, Pa., assignor to Selas Corporation of America, a corporation of Pennsylvania Application March 11, 1941 Serial No. 382,771 3 Claims. (Cl. 126-92) The general object of the present invention is to provide an improved gas burning heater adapted for use in heating rooms or spaces which may advantageously be heated by a gas burning heater suspended in the upper portion of the room or otherwise supported in the general manner in which lighting fixtures are suspended or supported.

In its preferred form-the improved heater comprises an upper bowl-shaped member of refractory material and a lower bowl-shaped shell or sheet metal member, the two members being in nesting relation, but spacedapart to form a combustion space having top and bottom walls, respectively concave and convex, and includes a gas burner in such space creating flame jets which extend away from the heater axis at points distributed about the latter, and which are generally tangential to the adjacent portions of the refractory bowl which is thereby heated to in-' candescence. A substantial portion of the heat liberated in the combustion space is transmitted to the space to beheated by radiation from the metallic bowl, and a major portion of the remainder of the heat'liberated is transmitted to the atmosphere in the space to be heated which is in contact with the metallic shell and is there by subjected to a convection heating efiect. The improved heater is characterized by its mechanical simplicity, the relatively low cost at which it can be manufactured and installed, and by the substantial heating capacity obtainable with a heater of convenient'bulk, comparable with that of an ordinary indirect electric lighting fixture, and by the novel character of its gas burner element.

For some uses, the supply of gas to each heater may be controlled manually, as by means of an to the heater, when contamination of the room atmosphere by the heating gases is objectionable from the ventilation standpoint, or because of the possible adverse action on certain metal treating or other work operations carried on in the room heated.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had to the accompanying drawing and descriptive matter in which I have'illustrated and described a preferred embodiment of the invention.

Of the drawing: I

Fig. 1 is an elevation of a heater and associated gas supply and control parts;

Fig. 2 is a partial section taken on the line 22 of Fig. 1; and r Fig. 3 is a section on the line 3-3 of Fig. 2.

The heater structure shown in Figs. 1, 2 and 3, comprises a bowl-like refractory body A of ceramic material, a gas burner B, a combustion chamber 0 crescent-shaped in section and having upwardly-extending sides, and a heat radiating bowl-shaped member D of sheet metal which forms the lower wall of the chamber C, the upperwall of the latter being formed by the bowl .A. The burner B is located within the space C and as shown is coaxial with the bowl A, and has orifices delivering flame Jets distributed about and extending away from the common vertical axis of the bowl and burner, and generally tangential to a convex imperforate surface zone of the bowl A, surrounding and displaced a shortdistance from said axis. cured at its upper end edge, as by screws D, to a depending rim flange portion E of a heater top member E. The member D is formed with a central air inlet opening D and D represents a shield or shade larger in diameter than "the opening D and normally held some distance below and coaxial with said opening by spring fingers D engaging the member D at the margin of the opening D The member E is formed of metal and as shown comprises a centra1 hub portion E an apertured body portion and radial stifiening ribs E The body portion of the member E is advantageously lined by non-metallic heat insulating material F.

The products of combustion formed in the combustion chamber 0 issue from the latter into the insulated space between the bowl A and the top member E, through ports A" extending through the bowl A adjacent its upper edge. The

products of combustion pass awayfrom the last mentioned space through one or more outlet ports F' formed'in the member F. Each port F may open directly to the space in which the As shown, the member D is seheater is located, when the heater is used in a room, shop or factory in .which the escaping products of combustion may be discharged into the room atmosphere without objectionable consequences, but when desirable, the products may be discharged into a vent pipe 1 leading. out of the space in which the heater is located.

The heater is supported by a vertically dismember I from a normally open position into a a closed position.

The valve I is moved into its closed position by a thermostatic element 'J, when the latter cools as a result of the extinction of the flame of a pilot burnervK. The thermostatic element J is a bimetallic disc having its center connected to the stem I of the valve I', and having its peposed tubular element or pipe member G. As

shown, the member G mechanically connects the bowl A and the top member E. To this end, the

member G'is formed with a collar G engaged I by the lower end of the hub E, and has a threaded upper end portion extending through the hub E, on which is threaded an end member G between which and the collar G the hub Fl is clamped. At its lower end, the member G is provided with an out-turned flange G in supporting engagement with an annular portion of the bowl A, surrounding the central aperture therein through which the member G extends.

' flow of gas into the chamber B when the flame The burner B in the preferred form illustrated comprises a metal casting formed with a central threaded seat B at its upper side into which is threaded the lower end of a gas pipe I. The latter is threaded at its upper end into the part G which connects the pipe I to a suspension and of the pilot burner K is extinguished. To this endthe disc J is arranged so that when hot its upper side is convex and it holds the valve I in its open position, and when the disc J cools it snaps into the position in which its upper side is concave and in which it holds the valve 1' in its closed position. In normal operation the disc J holds the valve I in its open position in consequence of the conduction of heat to the disc gas supply pipe IA. The burner casting is formed with a gas inlet chamber 3 in open communication with the bore of the pipe I and which in normal operation is in free communication with a subjacent gas outlet chamber 3. The cylindrical outer wall of the chamber 133 is formed with a plurality of small radially extending discharge orifices B". Each burner orifice B is coaxial with a corresponding mixing nozzle passage b in an annular mass of ceramic material surrounding and spaced away from the discharge ends of the orifices B In the preferred construction shown, the ceramic material mass comprises two annular ceramic bodies b, which may be counterparts of each other. Each part b is formed witha circular series of raised bosses or lugs b which abut against the corresponding bosses or lugs b of the other part b, when the two parts are assembled as shown in Fig. 2. The bosses or lugs 12 form the side walls of the orifices b. The bosses b of each member b and the surface of the latter from which the bosses project are shaped to give each orifice b' the shape of a venturi channel which is flattened, so that its transverse dimensions in the direction of the plane of the engaging ends of the bosses b are greater than its transverse dimensions in a direction transverse to such plane. As shown the ceramic parts b are held in place in the burner structure by screws b extending through the parts and each threaded into a correspondin radial arm B of the burner casting which extends between the lower end of flange G of the member G and the upper side of the upper burner part b.

Each arm B is formed with an uprising projection 13 adjacent its outer end, which directly engages the flange G and spaces the body of the arm 3* away from said flange so as*to limit the J by the disc support J and an armJ' thereof which extends into position to be heated by the flame of the pilot burner K.

The metallic parts of the burner B are protected against overheating by the cooling action of air drawn past the burner casting into the metallic pipe G by the chimney action of the latter which opens to the atmosphere at its upper end through portsG in the member G The air required for that cooling action andthe necessary combustion air enter the space C through the bottom opening D in the metallic member D and usually some additional air is drawn through the opening D into the space 0 and is moved through the space 0 by the chimney action of said space. If, as will probably be the case in most uses of the heater, the products of combustion are discharged directly into the space heated through the outlet ports 1'', the heat carried out of the heater by the products of combustion is directly utilized in heating said space.

In many cases, my improved heater units may be expected toreplace indirect lighting or other pose of encasing the supply conductors for the lamps. The latter are located a few inches above the top surface of the heater top member E. The pipe'IA also supports a light diffusing member M which may be a translucent glass disc, and is located a few inches above the lamps L. Advantageously the top surface of the member EA is polished, in some cases, it may well be a chromium plated surface. The provision of the polished heater top surface not only insures adequate light reflecting capacity, but tends to a reduced rate of heat radiation from the top of the heater. light diffusion member M also acts to reduce heat The.

heat insulation material F.

heater, as does the radiation from the top of the In the normal operation of the heater shown by Figs. 1, 2 and 3, each burner casting orifice B and the corresponding ceramic. material channel 12' coact to effect the typical Bunsen burner ac- I tion. The-gas jet discharged through the orifice 3* toward and in the axial direction of the passage b induces a flow into the latter of air which mixed with the gas in the passage b constitutes, with suitably proportioned apparatus, all or a major port.on of the air required for the combustion of the gas with which it is mixed. The air inducing action of the Jet discharged through I each orifice B may be augmented by providing the latter with a nozzle extension, formed as shown by a corresponding radial projection at the outer side of the wallof the chamber B The horizontal flattening of the passages b and particularly of the expanding discharge nozzle portion of the passage, has the eflect of flattening the burning jet extending away from the periphery of the annular ceramic body b, b, and of thereby increasing the heat radiation from the flame to the refractory body A.

In consequence of the fact that the channels b are surrounded by refractory material and of the further fact that the'jets of air and gaseous fuel mixture are discharged from the ports of the channels at regions alongside of and underlying the outer surface of the refractory material A, a substantial portion of the heat liberated by the flames produced by the jets is radiated to closely adjacent imperforate regions of the member A. This makes it readily possible to heat the mem- A, the portion of the latter immediately adjacent the burning jets is not cooled as it would be if the unbumt jet material impinged against said refractory member. In consequence, the temperature of the refractory material adjacent the jets is high enough to insure highly efficient combustion conditions, and the maintenance of gas temperatures throughout the combustion space high enough to insurethat substantially all of. the convex surface of the refractory member A is heated to incandescence. In consequence, all portions of the metallic shell D'receive heat by radiation at a relatively high rate from. the rerefractory member A, as well as by conduction from the gases in the space C. The entire outer surface of the shell D is thus adapted to radiate heat at a relatively high rate.

The metallic shell D receives heat by radiation from the more highly heated refractory bowl A and has its lower portion cooled and its upper portion heated by the air and gas flowing through her A to incandescence and to maintain high flame temperatures, whereby good combustion efilciency and a relatively large heat producing capacity Per unit of heater bulk are obtained.

With the approximately hemispherical form of the metallic member D, the distribution of the heat radiated by the heater is especially suitable for use in heating a room when the heater is suspended from the room ceiling. The relatively high combustion chamber temperature permits of emcient combustion with little or no excess air. A reduction in excess combustion air contributes directly to the maintenance of high combustion chamber temperatures and of a high thermal emciency. V mtended regular use of heaters constructed in accordance with the present invention have shown them to be practically effective, efficient,

and reliable in operation. Merely byway of ilthough having a top diameter of about 20 inches,

is adapted to liberate heat at a rate of approximately 40,000 B. t. as per hour, when ordinary town gas of about 500 B. t. u. value is supplied to the space 0. This tends to reduce the total heat absorption by the member D, which receives radiant heat from the more highly heated lower portion of the bowl A, relative to the heat absorptlon by the upper portion of the member D. This tendency to equalization of the temperature of difl'erent'portions of the member D is practically advantageous in that it tends to increase, rather than to decrease, the amount of heat radiated radially away from the member D while at the same time desirably reducing the heat radiation from the lower central portion of the member D which otherwise might be more intense than is desirable in many cases. I

As shown, though not essential, the refractory member A is formed in one piece and the thickness of the combustion space C diminishes in a generally uniform manner from the bottom of the space to its upper edge, so that theflo'w path for the heating gases maybe approximately uniform in'cross section from the burner to the outlet ports A.

the burner mixer, and to discharge heating gases through its outlet port or ports F at atemperature of about 500 F. As those skilled in the art will recognize, that low heating gas exit temperature necessarily means a relatively high heater efficiency.

The relatively high efficiency, and large capacity perunit of space occupied by the improved heater, are due primarily, I believe, to the temperature and combustion conditions prevailing in the combustion space C. Owing to the tangential disposition of the flame jets close to the lower central portion of the refractory member Preferably, and as shown, the member A has its convex under surface formed with grooves A extending circularly about the vertical axis of the heater. Such roughening of the convex surface of the member A adjacent the burner increases he heat absorbing of the burner and facilitates the maintenance of combustion.

To prevent back-firing inv the passages .b' I

may advantageously provide the burner with a fire screen, which, as shown in Fig. 2, is in the form of a short cylinder of wire netting Q having its upper and lower edges received in circular grooves b in each of the 'annular ceramic bodies b adjacent its periphery extending into the latter from its face adjacent the other body. This .application is a continuation in part of and supersedes my earlier application, Serial No. 246,321, filed December 1'7, 1938.

While in accordance with. the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention, as set forth in the appended claims.

Having now described my invention, what I claim as new and desire Patent, is:

1.-A heater adapted to radiate heat into a space to be heated, comprising a combustion to secure by Letters and heat radiating capacity chamber having a thin metallic heat radiating outer wall of hollow approximately semigiobular form, and having an inner wall of refractory non-metallic material and of globular form and adapted to radiate heat to substantially all portions of said outer wall along lines substantially perpendicular to the latter and a burner centrally located in said chamber and formed with orifices and adapted to discharge combustible fluid into said combustion chamber in jets directed away from the burner axis and an annular body of ceramic material surrounding said burner and formed with mixing nozzle passages respectively coaxial with said orifices and respectively adapted to receive said jets and air streams induced by said jets and to discharge air and gas mixture jets adjacent and generally tangential to corresponding portions of the refractory inner wall of the combustion space.

2. In an improved heating apparatus, the combination of an inner heat radiating bowl of refractory material and an outer heat reflecting bowl, said inner bowl being nested within said outer bowl to form a chamber therebetween, said chamber beingcrescent-shaped in section and having upwardly extending sides, a centrally disposed burner mounted in the lower part of said chamber and having a plurality of discharge ports closely adjacent to the outer surface of said inner heat radiating bowl, means whereby said burner is adapted to receive a mixture of air and gaseous fuel, said burner being constructed and arranged to discharge radially outward from said ports a plurality of jets of the air and gaseous fuel mixture at regions alongside of and underlying the outer surface of said inner bowl, the lower part of said inner bowl being imperforate at the regions alongside of which the jets are discharged, said jets being adapted to be ignited to produce flames from which heat is radiated to the closely adjacent imperforate regions of said inner bowl to heat the latter to incandescence, the heat radiated from said incandescent regions of said inner bowl being eflective to promote combustion of the jets and maintain high flame temperatures.

3. In an improved heating apparatus, the combination of an inner heat radiating bowl of refractory material and an outer heat reflecting bowl, said inner bowl being nested within said outer. bowl to form a chamber therebetween, said chamber being crescent-shaped in section and having upwardly extending sides, said inner bowl having a central opening in the lower part thereof, a centrally disposed burner in the lower part of said chamber, said burner having a plurality of discharge ports closely adjacent to the outer surface of said inner heat radiating bowl, piping extending downwardly through said inner bowl in alignment with the opening and having the lower end thereof connected to said burner. said outer-bowl having an opening at the vicinity of said burner, means including said piping whereby said burner is adapted to receive a mixture of air and gaseous fuel, said burner being constructed and arranged to discharge radially outward from said ports a plurality of jets of the air and gaseous fuel mixture at regions alongside of and underlying the outer surface of said inner bowl, the lower part of said inner bowl being imperforate at the regions alongside of which the jets are discharged, said jets being adapted to be ignited to produce flames from which heat is radiated to the closely adjacent imperforate regions of said inner bowl to heat the latter to incandescence, the heat radiated from said incandescent regions of said inner bowl being effective to promote combustion of the jets and maintain high' flame temperatures, and said chamber having one or more openings at the upper part of the upwardly extending sides through which products of combustion are discharged from said chamber.

FREDERIC o. HESS.

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