US2257399A - Gaseous fuel cookstove - Google Patents

Description

Sept. 30, Q E. PARKER GASEOUS FUEL COOKSTOVE Filed Oct. 20, 1938 4 Shee'hS-Sheet l 33a Il! f ladeff f Sept. 30, Q E, PARKER 2,257,399

GASEOUS FUEL COOKSTOVE 4 Sheets-Sheet I5 Filed Oct. 20, 1938 Arr *Y A. a/l/l/l//l/l/l/l/)lv/ 38 `J'zws'lzvr Claude EPaPJer sept. 3o, 1941. C, E, PARKER 2,257,399

GASEOUS FUEL COOKSTOVE Filed oct. 2o, 19:58 4 sheets-sheet 4 zaff- "Patented Sept. 30, 1941 GASEOUS FUEL COOKSTOVE Claude E. Parker, Chicago, Ill., assignor to Gas Products Corporation, Chicago, lll., a corporation of Illinois Application October 20, 1938, Serial N0. 235,961

11 Claims.

This invention relates more especially to the cooking top section of a gas stove or range, and has for some of its general objects to improve the emclency and appearance thereof, to apply the heat of the burner flames to the bottom of the cooking `utensil with greater eilectiveness, and to maintain the walls of the burner box relatively cool.

More specifically stated, it is an object of the present invention to provide a cooking top embodying a ceramic hearth overlying a burner head, having a novel correlation of the burner head to the slots in the hearth through which the llames escape, and which is of such character as to promote effective application of the heat to an overlying utensil and efficient mixing of fuel and secondary air.

Another object is to provide a cooking top embodying a ceramic hearth overlying a burner head, together with a novel arrangement for supporting the hearth in a protected manner in an aperture in the top panel while protecting the margins of the hole in the panel, by means of a supporting ring `for the hearth, from injury by hot gases directed laterally outward by the hearth.

A further object is to provide an improved burner structure which embodies a combustion chamber enclosing the gas discharge outlets of -the burner, which chamber serves to minimize the dissipation of heat to the atmosphere or to the burner box or associated stove parts, acts to coniine the heat and direct it upwardly to the utensil, controls and preheats the supply of secondary air admitted to said chamber to support combustion, and excludes harmful drafts of air which might adversely affect the operation or eiliciency of the burner structure. l

Further and ancillary objects, features and advantages of the invention will be understood from the following description and claims, taken in connection with the accompanying drawings, in which:

Figure 1 is a top plan view of a gas stove embodying the features oi' my invention.

Fig. 2 is a fragmental front elevation showing the upper portion of the stove.

Fig. 3 is a schematic view illustrating the manner in which the gas to the burners is controlled and automatically ignited.

Fig. 4 is a view in vertical transverse section through a. burner compartment, taken in the plane of line 4-4 of Fig. 1.

Fig. 5 is a vertical section in the plane of line l-S of Fig. 1, illustrating one form ot burner burner taken in the plane of line 1-1 of Fig. 1

and illustrating a portion of the automatic igniting means.

Fig. 8 is a diametric vertical sectional View oi a modiiied construction, illustrating the type of burner unit shown in Fig. 4 in connection with a special guard ring mounted in the top panel opening around the burner unit.

Figs. 9 and 10 are `views similar to Fig. 8, but showing modified forms of the burner units.

Figs. 11, 12, 13 and 14 are perspective views of one form of burner unit, Fig. 11 showing the ceramic-retaining ring, Fig. 12 showing the twopiece ceramic top, Fig. 13 showing the ceramic supporting plate, and Fig. 14 showing the burner head and bottom plate of the unit.

While my invention is susceptible of embodiment in various modifications or alternative con-` structions, I have illustrated in the drawings and will herein describe in detail some of the pre- Ierred embodiments without, however. intending to limit the invention to the exemplary forms illustrated and described. I aim to cover in the appended claims all equivalents of the disclosure falling within the spirit and scope of my invention.

In the illustrative construction Figs 1 and 2) the invention has been shown as embodied in a cooking top for a gas range of the familiar dlvided-top cabinet type, but the invention may,

of course, be applied to cook stoves or ranges o! any desired type. The cooking top oi the exemplary range embodies a continuous sheet metal top plate Il having four burner openings 2| in it, bordered by reenforcing iianges 22, and which receive burner units constructed in accordance with the present invention. These burner units extend down into burner boxes in the stove body, the bottom walls of which are deiined by horizontally slidable drip pans I8 (Fig. 4). The stove body is ot generally conventional form and, hence, need not be detailed. Any suitable means may be employed for supporting the burner units but it is desirably such as to minimize conduction of heat to the top plate I0.

To provide a cooling air source for the top plate III, the burner units are made of lesser diameter than the holes 2l so as to leave annular spacesll about their perimeters and through which cooling air may iiow upwardly from the burner box over the lip of the top panel. When a burner is in operation, some of the heat generated thereby will warm the surrounding air in the burner box causing it to rise through said annular cooling passage 2|, and air to supplant that flowing upwardly through said passage is drawn upwardly through the space between edges of the drip pan I 8 and the side Walls'of the burner box. Some of the' heated air from the burner box may also escape through holes I1 in the rear wall of the burner box into a rear ue passage and thence out of the `stove through an outlet I1a to the atmosphere or to the usual flue pipe, as the case may be. In this manner there occurs a constant change of air in the burner box so that the walls thereof, including the top panel I0, will be maintained at such a low temperature that there is no danger of one being burned by contact therewith or of damage to the nish on the top` panel adjacent to the burner units.

Turning now to the burner units per se, each of them embodies two principal elements, namely,

a superstructure lying generally in the plane of the top plate III and a burner head substantially hidden beneath this superstructure. I have shown in the drawings two different forms of burner heads, as well as alternative forms of superstructure associated therewith. In one form of burner head, seen in Figs 9 and 14, all of the gas-discharge outlets may be supplied from a single 'chamber and single supply pipe. The other form comprises two separate chambers fed from a dual supply pipe. One chamber, located centrally of the burner, is small and is used as a so-called simmer burner, while the other surrounding chamber is of much larger capacity. 'Ihe dual gas supply pipe is associated with valve-control means operable in the usual manner to supply gas to both chambers conjointly or to the simmer chamber only, as maybe desired'.

Referring iirst to the simpler form of burner head having a single chamber, as illustrated in Figs. 9 and 14, the burner comprises a central chamber 23 and a plurality (in this instance four) of chambers 24 communicating therewith and extending radially outward therefrom. Said radial chambers have gas-discharge outlets which in the exemplary embodiment shown are ports or orifices 25 in the upper sides of the chambers. The central chamber has a lateral gas inlet opening (not shown) in communication with a supply pipe or venturi 26.

Suitably secured to the underside of the burner head is a baie or .bottom wall 21 which closes the bottom of the combustion chamberl to be later described. The upper side of each of the radial chambers 24 is formed with a marginal rib 28 through which the discharge ports 25 pass, said rib defining a recess in the upper wall of the chamber. Lugs 29 on the ends of the chambers are provided to interlock with parts of the superstructure, as will be explained.

Referring to Figs. 3 to 7, the dual chamber burner head, in the preferred form illustrated, comprises an outer ring-chamber 30 constituting asupply conduit, a plurality of branch chambers 3l communicating therewith and projecting radially inward therefrom, and a small central simmer chamber 32 which is out of communication with the other chambers although all of the chambers may, if desired, be formed in an integral casting. Gas-discharge ports 33 are provided in the radial chambers 3l, and the ringchamber has a gas inlet opening 34 in its lower wall. The simmer chamber is provided with gasdischarge ports 35 in its upper wall and with a. gas inlet opening 36 in its lower wall. Marginal ribs 31, through which the gas ports 33 and 35 pass, are formed on the top walls of these chambers, said ribs defining open-top recesses to receive and interengage with parts of the superstructure to be later described.

Any suitable well known form of gas and primary airsupply arrangement may be provided for the dual burner head as, for example, a dual supply tube 38 (Fig. 3) comprising two separate' Venturi tubes 38a and 33h for the main and simmer portions, respectively, of the burner. In accordance with standard practice asingle valve 44 is used to control the supply of gas to both sections of the burner head. 'Ihis valve is operable in a well known manner to move from an 05" position in which the supply of gas is cut oil.' to both burner sections, or to a simmer position in which gas is supplied only through the tube v38b to the simmer section, or thirdly to an on position irr which Agas is supplied at a controlled rate to both the simmer and main sections of the burner through the tubes 38a and 38h. Also, in accordance with present day practice automatic ignition means is provided for the. burner head. For this purpose flash-back tubes 52 lead from a central pilot burner 5I to lighter ports 53 which communicate with the central supply chamber 32 in the burner head. When the valve 44 is turned to its simmer position gas is supplied through the tube 33b to the chamber 32 from which it escapes from the port 53 down the tube 52 and is ignited by the pilot burner. The resultant flash-back in the tube 52 ignites the fuel escaping from the other ports in the simmer head. In case the valve 44 is turned to its full on position the iiame is quickly propagated to all of the main ports 33 alter the simmer section ports have been lighted, as described.

To insure travel of the flame from the initial ignition port 53 of the simmer burner to the other ports, it may be desirable to provide in the simmer chamber an additional port or ports, which may be termed flame carry-overports, only one such port being herein shown at 58. The location and spacing of all of the burner ports is such that the flame from the initial ignition port 53 will be rapidly spread from port to port in all of the chambers when the control valve 44 is in a position to supply gas to all of said chambers.

As to the second main elements of the burner units, that is, the superstructures which overlie the burner heads described above, this second element comprises, in general, a horizontally disposed disk-like Wall, the upper face of which is above the plane-of the gas outlets of the burner head and below the plane of the seating sur- `faces on which the bottom of the utensil rests. The said wall comprises an annular rim or peripheral portion which is substantially continuous or solid, and in a central zone it has one or more openings or apertures permitting the passage upwardly therethrough of the llames or burning gases from the burner outlets. In the form shown these openings are narrow slots registering with the pattern of the orifices in the burner head, the exemplary arrangement of slots illustrated in the drawings being cruciform in shape with the ends of the cross forked so that each arm of the cross is Y-shaped, as clearly seen in Fig. 1. This arrangement aiords even distribution of the gas flames throughout the central area of the burner unit. It will be understood. however, that many varied patterns,

shapes or arrangements of the central opening and the burner outlets may be adopted without departing from the invention.

Above the upper surface of the concentratordistributor structure is provided a plurality of spaced upstanding supports, the upper edges of which collectively provide a seating surface on which the bottom of a cooking utensil A may be seated, as seen in Fig. 5. In the present instance these supports are inthe form of radial ribs extending inwardly from the peripheral portion of the structure to a point adjacent the slots.

Referring now to the complete burner unit shown in Figs. 9 and l1 to 14, the structure comprises, in addition to the burner` head 23, 24 and bottom plate 21, a metallic supporting element 59 embodying a disk 58! having a solid peripheral area and an apertured central area. the shape of which is deflned by projections Il and 6| extending radially inward, the longer projections 60 being dimensioned to flt into the open top recesses defined by the ribs 18 on the burner head, and thethickness of said projections being such that their upper surfaces are approximately flush with the upper edges of the ribs 28 on the radial burner arms. Depending from the disk 59* is an annular iiange 62 having notches E3 in its lower edge to receive and rest upon the lugs 29 on the burner arms, the interlocking of these lugs and notches insuring proper positioning of the element 59 on the burner head. At the periphery of the disk is an upstanding flange 84 and a plurality of inwardly projecting lugs 65.

The top element 55, seen in Fig. 12, is a fiat disk-like body comprising an outer rim or peripheral portion, of substantial radial dimension, which presents a substantially continuous or solid wall surrounding a central opening through which the flames from the burner head may pass upwardly. Preferably this element is made of fused heat-insulating material such as ceramic,

refractory, or like material, and it may be made of a unitary piece, although it is preferable to form it in a plurality of separate sections if ceramic or refractory material isused. Two such sections are shown in Fig. 12. Preferably each section, whether two or more, is a duplicate of each other section so that the sections are universally interchangeable. In the form shown in Fig. 12, a portion at the edge of the upper surface of the ceramic is depressed, as at 5l, and each section has a notch 69 in its edge to receive one of the inwardly projecting lugs l5` on the supporting element so as to locate the` ceramic pieces properly on said element.

The edges of the flame slots 1U in the top wall are preferably provided with notches, ribs or corrugations which will more rapidly become heated by the ames. The exemplary formof slots shown provides four long projections 55" and four short projections Sib which rest upon and conform to the long and short projections il and 6|, respectively. on the underlying supporting element 59, whereby all parts of the ceramic are supported and reenforced. On the upper surfaceof the` ceramic are preferably formed low ridges 1I following the contour of the slots 10 and spaced slightly from their edges, said ridges serving to impede the flow `into the slots of any liquid spilled on the top surface of the ceramic. Preferably the upper surface oi' the ceramic slopes downwardly and outwardly from a central point to drain of! liquids spilled thereon.

Utensil supporting ribs 12 are also formed on the upper side of and integral with the wall, and extend from its peripheral portion inwardly to a point just short of the inner ends of the respective projections 55* and I5".

Desirably, the top elements like 56 are made of ceramic material covered with a fused vitric glaze. such a material suitable for the purpose being sold upon the market under the trade name Parkerite A metallic retaining ring 13, seen in Figs. 8 and 11, comprises a horimntal portion overlying the depressed peripheral portion 8l of the ceramic and a downwardly extending portion which surrounds the ceramic and extends to a point in abutment with or adjacent tothe upper edge of the marginal flange il onthe supporting element 59. The ring andsupporting element may be secured together in any suitable way, as by screws passing up through holes 14 in the supporting element and threaded into the ring. 'I'he parts are so arranged and dimensioned that when the ring 1l and supporting element 59 are secured together, a space is left between the peripheral portion of the ceramic and said ring and element to allow for expansion of the ceramic under heat. Clearance may also be allowed between the sections of ceramic for a like purpose; and the arrangement and distribution of the flame slots 10 inthe ceramic also contribute toward avoidance of breakage of the ceramic by internal stresses caused by heat.

On the upper face of the ring 13 are a plurality of ribs 15 spaced so as to be in alinement with the outer ends of the ribs 12 on the ceramic. 'Ihe ribs 15 preferably project beyond the periphery of the ring to bridge the air slot 2|'L which surrounds the burner unit, as seen in Fig. 4. and the upper edge of the ribs may be downwardly curved or inclined to facilitate the movement of a cooking utensil from the stove top onto the burner unit. These ribs may also project inwardly from the ring so as to overhang the ceramic to any desired extent, and if desired the ceramic ribs 12 may be eliminated in whole or in part, being supplanted by the inward projections of the ribs 15.

Raised bosses 16, shown in Fig. 1. may also be formed in the top panel It adjacent to the burner openings and in alinement with the ribs on the burner unit to serve to support a utensil `in spaced relation to the top panel in case a large utensil is placed over the burner when the top wall structure has been temporarily removed so as to guard against smothering of the flame from the burner in this contingency.

When the parts seen in Figs. 11 to 14 are assembled, the burner head is enclosed by the overlying wall structure, the depending flange 62 and the bottom wall 21, as indicated in Fig. 9, thereby providing a lower air-preheating chamber and a primary combustion chamber which includes the slots 10 in the ceramic. Provision .for the admission of secondary air to support combustion in the chamber may be made in any suitable way, as by spacing the bottom plate 21 below the lower edge of the flange 62 to form an annular slot 11 surrounding the lower portion of the burner head beneath the gas-discharge orifices. A portion of the gas-supply tube 38* also constitutes a portion of the bottom closure in the present instance.

Heat from the burner which would otherwise be laterally and downwardly dissipated into the burner box is thus largely saved and is reflected upwardly through the slots v1i) to be used eifec'- tively against the utensil A. The secondary airinlet slot 11 may b e so proportioned in size that air from the burner box will be constantly drawn therethrough into the lower part of the chamber where it will be preheated, and the air will thence ow upwardly into the slots 1|) to commingle with jets of gas and thus supply the proper mixture for complete combustion in the space provided between the bottom of the utensil and the upper surface of the top wall. This space, it will be observed, constitutes a secondary combustion chamber communicating with the lower chamber through the outlet slots thereof.

In the dual form of burner the ring-conduit 30, supplanting the flange 62, provides the side walls of the lower chamber (Figs. 4, 8 and 10). the bottom of which is defined by a plate 18 which may, if desired, be cast integral with the dual gas-supply tube 38, said plate 18 being spaced from the lower wall of the ring-conduit 30 to provide a peripheral slot 11' for admitting secondary air.

The means for supporting the burner units in the burner box may take various forms, two forms being herein shown by way of illustration. Referring to Fig. 4, the burner unit may be supported at one side by a small bracket 19 secured to one side wall of the burner box and at the opposite side by two brackets 80 which may be in the form of a unitary base with two arms underlying the peripheral portion of the burner, the unitary base being secured to the opposite side wall of the burner box. Preferably at least one of the horizontal arms of these brackets has an interlocking relation with the burner head to insure proper location of the burner, this being accomplished in the exemplary embodiment l1- lustrated by means of a pin 8| projecting downwardly from the peripheral portion of the burner head and engaging in a hole in the bracket arm.

'I'he form of vburner unit shown in Figs. 9 and 1l to 14 may be mounted on a three-arm support 82, the ends of which are suitably secured to the side walls of the burner box, one arm of the support underlying the gas-supply tube 26 and the opposed pair of arms underlying the bottom wall 21. Pins 83 projecting downwardly from said tube and wall engage in openings in the support 82 to locate the burner unit in proper position.

It will be observed that the supporting means for the burner units is of such a character that there is no direct connection between the peripheral portion of the burner unit and the top wall l0, so that there is no direct conduction of heat from the burner unit to said top wall. Any heat transferred to the walls of the burner boX by direct conduction will be that passing through the burner supporting brackets and these brackets are maintained relatively cool by the air circulation through the burner box.

In Figs. 4, 8, 9 and 10 I have shown alternative forms of top wall structures and means of supporting them. In Fig. 4 is shown the dual form.

of burner head already described, on top of which is mounted a disk 59b corresponding to that shown in Fig. 1.3 but omitting the depending annular flange 82, the disk and burner having suitable interlocking parts to insure proper assembly and retention of the disk. In this illustration the burner unit is mounted at such elevation that the upper surface of the ceramic wall ing ring 13 is modified. In this view the burner unit is mounted in a position such that the upper edges of the utensil-supporting ribs 12 and 15 are located a much shorter distance above the plane of the top panel I0 of the stove, so that the upper surface of the ceramic is located slightly below said top panel. Surrounding the burner unit and mounted upon a downwardly and inwardly turned flange 84 formed on the top panel at the margin of the burner opening is a supplemental ring 85 having radial ribs 86 which slope downwardly and outwardly from their inner ends to a point adjacent to the plane of the top panel I0, said ribs being spaced and located in alinement with the utensil-supporting ribs on the burner unit. The ring 85 comprises a slightly coned body with a depending internal marginal flange, and may be mounted on and secured to the flange 84 in any suitable way. In the present instance the ring has a series of small bosses 85a on its underside resting on the flange 84 and secured thereto by screws 85b each passing upwardly throughthe flange and threaded into one of said bosses, the latter acting to space the ring and flange apart so that there is provided an annular air passage 81 between said ring and said flange, through which air may ow upwardly from and out of the burner box. This air space is in addition to the annular air space 2|a provided between the inner side of the ring and the periphery of the burner unit, as clearly shown in Figs. 8 and 9. This dual annular air passage more effectively prevents conduction or radiation of heat from the burner unit to the top panel I0. The ring 85 serves to permit lowering of the burner unit relative to the plane of the top panel without danger of choking or obstructing the escape of gases of combustion from the space between the top wall and the utensil. Lowering the burner `unit relative to the top panel makes it somewhat easier to slide a utensil from the top panel onto the burner unit over the' skidways provided by the upper edges of the ribs 86 on the ring. 'I'he cone shape of the ring acts to deilect or reflect the heat from the escaping products of combustion back toward the utensil.

In Figs. 9 and 10 the metallic retaining ring, such as shown in Fig. 11, is omitted and the ribs 12 on the ceramic are extended to the periphery thereof. The ceramic may be readily lifted off from its underlying supporting structure, being normally held in place by gravity and by upstanding bosses 88'on the support engaging in peripheral notches in the respective sections of the ceramic.

In Fig. 10 the supporting element corresponding to that shown in Fig. 13 is omitted and the ceramic rests directly upon the burner head, the latter being provided with an upstanding peripheral flange 89 and with projections 90 extending inwardly from the upper portion of the v ring-chamber to underlie and reenforce the ceramic, said projections corresponding in shape to the pattern of the apertured area of the ceramic in a manner similar to the projections 60 and 6I seen in Fig. 13.

In Fig. 10 also the upper edge of the outer end portion of each ceramic rib is downwardly inclined or curved, and said outer end portions may be substantially thickened laterally so that they may serve as utensil skidways without undue danger of breakage of the ceramic by sliding utensils from the stove top onto the burner when the burner unit is mounted in the relation seen in Fig. 4. If a guard ring 85 is employed, the outer ends of the ceramic ribs may be shaped as seen in Fig. 9 to complement the ribs 8G on said guard ring.

Preferably the opposed side walls of each of the slots 1|! in the ceramic converge or taper upwardly. as clearly seen in Fig. 5, which is a section on irregular line 5-5 of Fig. 1. The gas-discharge vorifices in the chambers 24 are somewhat inclined `to prevent any lateral deflection of the flame.

jets until they reach said space. If desiredpthe width of the upper edges of the slots and the spacing of the gas-discharge orices may be so correlated that the flame jets will completely filithe slots at their upper edge.

Referring to Fig. 5, the jets of flame have been indicated somewhat diagrammatically and roughly to illustrate the action of the burner unit when in full operation, i. e., when the gas is turned on to the full extent, the inner heavy lines within Y in their escape.

the ame jets representing the so-called inner cones of the jets. The force ofthe gas issuing from the discharge orifices sets up an injector- `like action to draw secondary air upwardly into the slots 10 and the walls of said slots constitute flues enclosing the lower portions of the flame jets. This results in an elongation of the flame jets beyond a length which would obtain under like conditions if the superstructure were vremoved from the burner. It will also benoted that the walls of the slots overhang the gas-discharge orifices in the burner head, thereby serving as' a guard to protect said orifices from being clogged by foods which may be spilled on the burner unit.

The relationship of the three general planes of the utensil-seating surface, the upper surface of the top wall, and the series of gas-discharge oriflces in the burner head is important, being such that when the burner is in full operation the cooler portions and inner cones of the name jets are located below the plane of the upper surface of the top wall, while the hot tips or upper portions of the flame jets extend above said upper surface into the secondary combustion chamber `formed between it and the bottom of the utensil. The most intense heat from a gas jet `flame is that at the upper tip of the flame. By

spacing the gas burner outlets as described, advantage is taken of this fact so that the utensil bottom is located in the plane of most intense heat. Preferably, this location is such that the upper tips of the flames lap the utensil bottom and are thereby laterally spread or distributed.

The spacing of the upper surface of the top wall below the plane of the utensii-seating surfaces is such that the chamber thus provided is of ample volume to permit complete combustion of the gaseous mixture without causing choking or sputtering, while permitting suiiicieritly free exit of the products of combustion from the periphery of the chamber. The exit throatway between a utensil and the solid peripheral area of the top wall functionsto control or retard the escape of the products of combustion sulcient to provide smooth or even operation of the burner. This exit throatwayis just suiiicient to permit the egress of the products of combustion and it thus serves to prevent the ingress of cold air into the combustion chamber beneath 'the utensil.

Referring to Fig. 1, it will. be noted that the arrangement of the flame slots 10 and utensil supporting ribs 12, 15, is suchthat from any and all parts of the flame slots there is provided an unobstructed substantially radial path for the escape of products of combustion to and through the peripheralexit throatway. so that no section of the burning gases or products of combustion need crowd through, over or around any other section This contributes to smooth and steady operation of the burner unit.

The ceramic material of the top wall, when it becomes hot or incandescent, also contributes to combustion and to uniform distribution of heat throughout the combustion chamber and under the whole area of the utensil bottom. The heat absorbed by the top wall will continue to be given off after the gas to the burner has been shut off, thereby effectively continuing the cooking operation without the flame burning. The ceramic top wall also acts to some extent as an insulator to minimize conduction of heat to the peripheral portions of the burner.

'I'he combination of features described maintains a blanket of intense heat close to and substantially uniform throughout the area. of the utensil bottom, even to the peripheral portions thereof, thus serving to increase the range or diameter of the eiective zone of heat substantially beyond the area occupied by the gas burner outlets. A much greater proportion of the heat generated by the burning gases is applied direct-f 1y to and distributed evenly beneath the utensil, with a minimum of dissipation of the heat to the other stove parts and the atmosphere.

When the top wall is made of ceramic material it is desirable from a practical standpoint to make the wall of substantial thickness to guard against the danger of breakage of the ceramic by accidental dropping of a heavy utensil or implement p thereon. In such case the practical thickness of need not be as thick, in which case preservation of the depth of the flame slots may be effected by providing flanges at the edges of the slots depending from the thinner top wall to a point adjacent to the burner orifices.

Either the top wall structure or the burner units as a whole may be easily removed. In the case of the burner unit shown in Figs. 9 and 11 to 14, the removable portion comprises the three parts seen in Figs. 11, l2 and 13, which are fastened together by screws inserted through the holes 14, this assembly being capable of ready removal from. its supports on the burner head. Similarly, in Fig. 8 the three-pieceassembly may be lifted off from the burner ring-chamber 30. In Fig. 10 the removable top wall consists merely of the ceramic wall which rests directly upon the burner head.

In thus providing for ready removal of the top My copending application Serial No. 272,984,

led May 11, 1939, and which is a continuation Y in part of the present application, discloses a gas stove cooking top structure embodying certain improvements over that herein `shown and contains claims generic to the earlier structure herei in disclosed, the claims in the present case being,

insofar as said last-mentioned application is concerned, specific to the structure herein disclosed and not generic to the improved structure disclosed in said last-mentioned application.

I claim as my invention:

1. A gas cook stove having, in combination, means for supporting a cooking utensil with its bottomv surface exposed, a burner having a plurality of radial arms with outlet means at opposite sides thereof for discharging gaseous fuel upwardly and laterally beneath a utensil so supported, and a hearth located immediately beneath said utensil-supporting means to define between the top surface of the hearth and the utensil bottom surface supported on said means a vertically shallow combustion space, said hearth comprising a substantially flat refractory disk overlying and substantially concealing the burner and having slots disposed above and at opposite sides of the burner arms for the passage of gases in process of combustion into the combustion space, said slots being of substantially greater width at the bottom of the disk than at the top thereof, `and. said slots being only partially underlaid by the burner arms to permit an updraft of secondary air through the unclosed lower end portions of the slots to flames issuing from said burner outlet means.

2. A gas cook stove, comprising, in combination, a main top panel having an opening therein, a burner disposed centrally of said opening and having fuel discharge outlet means disposed in `a plane a short distance below Ithe plane of said top panel, and means for intensifying'the application of the heat of the flames or gases while in process of combustion to a utensil supported .above the burner comprising a refractory disk overlying the burner and substantially concealing the same, said disk having a generally flat top face located slightly below the plane of the top panel, a metallic ring supported with its outer edge lsubstantially inthe plane of said top panel and with the top surface of the ring sloping downward and inward from such outer edge toward the plane of the top face of said disk, and a plurality of circumferentially spaced ribs carried by said metallic ring and providing utensil seating surfaces disposed in a plane a short distance above the plane of the top panel, said refractory disk being-slottedfor the passage of such llames and having a top face positioned in ing fuel discharge means spaced below the bottom of a utensil resting on saidl seating surfaces. ofan annular structure defining about said burner a laterally closed combustion chamber having below said fuel discharge means an inlet for secondary air, said structure comprising a central `disk shaped portion apertured to form a grid and a top4 ring portion ofv substantial lateral kwidth surrounding the grid portion and having an upwardly facing heat radiating surface spaced a short distance below the plane of said seating surfaces, said grid and top ring portions coasting with the bottom of a utensil supported on said seating surfaces to provide ow controlling passages for the slow escape of hot gases incident to combustion rst upwardly against and thence laterally outward beneath the bottom of said utensil.

4. In a gaseous fuel cook stove, the combination of a burner having a plurality of generally upwardly directed discharge ports, a top structure including a ring shaped portion, means coacting with the ring shaped portion to form beneath it a closed chamber surrounding the burner discharge ports and providing an inlet for secondary air below said burner ports, means located centrally of the top ring shaped portion defining a restricted outlet from said chamber for the products of combustion and a plurality of laterally spaced members providing utensil supporting surfaces spaced a short distance above the upper surface of the ring shaped portion, said ring shaped portion providing between it and the bottom of said utensil a passage for the radial discharge of the products of combustion escaping throughsaid outlet.

5. In a gaseous fuel cook stove, a burner assembly comprising a top structure including a ring shaped portion, means below said ring shaped portion of said top structure to form a combustion chamber, a vburner adapted to discharge into said chamber, a heat storing member located centrally of said top ring shaped portion and defining therewith a restricted outlet from the chamber for the passage of the products of combustion, and means providing a plurality of laterally spaced seating surfaces disposed above said ring shaped portion and said central Such C1080 Proximity to the plane of said seating surfaces as to confine such flames closely bel tween the bottom surface of a utensil resting on 4said seating surfaces and the vtop face of said recooking utensil anda gaseous fuel burner havmember for engagement by the bottom of a utensil. said member having an upper surface disposed substantially in the plane of the upper surface of said ring shaped portion.

6. The combination of a burner having a horizontal series of fuel discharge ports, a combustion chamber surrounding the fuel discharge ports and comprising a bottom wall and an upright side wall, a top structure including a ring shaped portion at the upper end of said upright wall and defining an opening above the burner, a plurality of supporting members providing utensil seating surfaces above the top structure, and an element in said top structure located centrally of said ring shaped portion and providing a plurality of spaced heat radiating elements and outlet passages from said chamber opening at the top of the element and connecting with the spaces between the utensil supporting members, said chamber having a secondary air inlet in itsy lower portion' below said burner discharge ports.

'1. In a gaseous fuel cook stove, a gaseous fuel burner having a horizontal series ,of fuel discharge ports, a plurality of utensil supporting members providingseating surfaces, and a burner assembly comprising an annular structure surrounding the burner` and coacting with the bottom of a utensil resting on said seating surfaces to control the flow of hot gases outwardly beneath the utensil, said annular structure having an upright wall extending upwardly externally of said discharge ports, a top Wall spaced below said seating surfaces to form with the bottom of a utensil lateral discharge passages closed at their lower sides and a plurality of spaced heat radiating elements spaced a short distance below the plane of said seating surfaces so as to be disposed immediately beneath the utensil bottom and directly exposed to and adapted to be lapped by the flames issuing from the burner and contacting with the utensil bottom, said annular structure defining about and above the burner ports a. laterally closed combustion chamber having an inlet for secondary air.

8. In a gaseous fuel cook stove, the combination with a gaseous fuel burner having fuel discharge means, of an annular structure defining about said burner a laterally closed combustion chamber having below said fuel discharge means an inlet for secondary air, said structure comprising a central apertured grid portion and a top ring shaped portion of substantial lateral width encircling the grid portion and having upwardly facing heat radiating surfaces, said grid portionproviding a plurality of spaced heat radiating elements interposed in the path of the flames and gases incident to combustion and retarding the escape of the gases from said chamber, and means providing a plurality of utensil seating surfaces disposed in a plane spaced a short distance above the grid portion and top ring portion, said grid and top ring portion coacting with the bottom of a utensil resting on said seating surfaces to provide passages for the escape of the hot gases passing upwardly from the combustion chamber and thence laterally outward beneath the bottom of the utensil.

9. In a `gaseous fuel cook stove, a burner assembly comprising, in combination, a top structure of generally disk shaped configuration having apertures in its central portion and an imperforate marginal portion of substantial latveral width encircling said central portion, a

burner head disposed beneath said top structure and having fuel emission means for directing flames laterally outward and upward through said apertures, means for supporting a utensil in closely spaced relation above said top structure to confine products of combustion issuing from said apertures between the utensil bottom and said annular portion of the top structure, and means including a generally horizontal baille located in spaced relation below said burner head and said top structure for intercepting any heat flowing downwardly and reflecting it back toward the utensil bottom, said baille defining a secondary air inlet adjacent the periphery thereof and at a point disposed a substantial lateral distance from such fuel emission means.

10. In a gaseous fuel cook stove, a burner assembly comprising, in combination, a burner head, a closure structure having upper and lower portions disposed respectively above and below the burner head and defining therebetween a secondary air inlet adjacent the periphery of the structure and at a substantial distance outward from the burner head, said upper portion of the closure structure comprising a ring of substantial lateral width encircling an apertured center through which products of combustion `emerge from the burner head and said lower portion of the structure comprising a horizontal baille wall for intercepting and reflecting any downwardly flowing heat.

11. In a gaseous fuel cook stove a burner assembly comprising, in combination, a closure structure of generally squat, cylindrical shape including an annular side wall portion and top and bottom walls, fuel emission means within said structure, the central portion of the top wall of said structure being apertured for the emission of products of combustion, means for supporting a utensil in closely spaced relation above said top wall, said bottom wall forming a generally horizontal baffle for interception and reflection of downwardly flowing heat, and said bottom and side walls defining, along their line of juncture,

a generally annular slot for entry of secondary air into the closure structure.

CLAUDE E. PARKER.

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