US3213920A - Gas burner - Google Patents

Description

Oct. 26, 1965 HQFF 3,213,920

GAS BURNER Filed June 26, 1963 2 Sheets-Sheet 1 FIG- 2 INVENTOR.

JOHN M. HOFF F|G 4 gi ATTORNEYS Oct. 26, 1965 Filed June 26, 1965 J. M. HOFF GAS BURNER 2 Sheets-$heet 2 INVENTOR.

JOHN M. HOFF KI'TORNEYS United States Patent 3,213,926 GAS BURNER John M. Hoif, Mansfield, Ohio, assignor to The Tappan Company, Mansfield, @1120, a corporation of Ohio Filed June 26, 1963, Ser. No. 290,693 4 Claims. (Cl. 158-116) The present application is a continuation-in-part of my application Serial No. 606,004, filed on August 24, 1956, and now abandoned.

This invention relates, as indicated, to a burner for gaseous fuel and more particularly to an improved top burner of a gas cooking range.

In cooking range applications especially, such a burner should have a low turn-down, that is, it should operate to maintain good combustion with minimal amounts of fuel being supplied, to provide a low or warming heat condition. Clean combustion in all settings is obviously desired, and the construction should preferably be such to permit the housewife or other user of the range easily and quickly to remove particles of food and other matter which may inadvertently be deposited on the burner.

It is a primary object of my invention to provide a gaseous fuel burner of improved over-all efliciency, with particular regard respectively and jointly to the abovenoted characteristics. It is an additional object to realize such improved operation in a construction which is readily and inexpensively produced.

Another object of the invention is to provide a burner of this type so designed and constructed as to maintain a smooth flow of the gases supplied thereto, without a material drop in velocity, such feature being believed responsible in large measure for the excellent efliciency of the new burner. It is a further object to provide a burner for gaseous fuel having a continuous outlet at which combustion takes place and specially formed deflector or baffle means assisting in maintaining the flame at very low settings.

It is also an object of the invention to provide a cooking range top burner distinguished by the noted features and further being adaptable to the addition of a central thermostatic unit of conventional sort disposed to bear against the underside of a pan and the like supported above the burner.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention'then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawings:

FIG. 1 is a side elevational view of a burner in accordance with the present invention and showing the manner in which it would preferably be used as a cooking range top burner;

FIG. 2 is a top plan view of the burner proper, that is, without the range elements illustrated in FIG. 1;

FIG. 3 is a longitudinal section as viewed from the plane of the line 3-3 in FIG. 2;

FIG. 4 is a fragmentary radial section taken on the plane of the line 44 in FIG. 2;

FIG. 5 is a similar fragmented section taken on the plane of the line 55 in FIG. 2;

FIG. 6 is an enlarged transverse sectional view of the burner head portion in which the flame condition at low rates of flow is represented;

FIG. 7 is a view similar to FIG. 6 but showing the 3,213,920 Patented Oct. 26, 1965 nature of the flame at intermediate or medium flow rates; and

FIG. 8 is another view on the same order in which the flame pattern is shown as it exists at full or high rates of gas flow.

More specifically, the range surface burner assembly illustrated in FIG. 1 comprises a portion 10 of the usual top panel of the range which is formed with a circular opening 11 to accommodate the heating unit. As is conventional, a dished shield 12 providing a depressed central opening 13 of reduced size is mounted in the top panel opening, and a grate 14 is provided over the opening to support the utensils in which the cooking or heating is to be accomplished.

The new gas burner includes a head portion designated generally by reference numeral 15, with a mounting flange 16 at one side for securing the burner to a structural member of the range, such as the plate 17, to position the head portion in the center of the surface unit opening 11. This head portion has a vertical axis, and a mixing tube 18 extends integrally radially outward from the head portion 15 at the side of the same generally opposite to the mounting flange 16. This mixing tube terminates in a usual flared mouth 19, with the latter being fitted with a conventional end cap 20 having portions through which air enters for mixing with the gas delivered to the burner.

I have also shown this unit to be equipped with a pan engaging thermostatic device 23 for automatic control purposes. This device and its operation are conventional and need not be described other than to note that the new burner is designed to accommodate the same centrally, the device here being supported on an extension 24 of the mounting plate 17 to project through the burner body.

Coming now to the detailed construction of the burner, the head is approximately cylindrical in its lower outer portion 25, with the inlet or mixing tube 18 blending smoothly and upwarly therewith as illustrated. The bottom wall 26 is dished and has a circular center opening formed therein. A small inwardly directed flange 27 and a contiguous vertical flange 28 bound such opening to form a seat for a purpose to be described.

An outer wall 29 of frusto-conical shape extends upwardly from a plane spaced above the lower wall portion 25 and at the approximate level of the uppermost portion of the mixing tube. The reduced end 30 of this outer wall is at the top and has a horizontal top face 30a. This end portion of the outer wall is also formed with an interior axially extending surface 30b, which is cylindrical about the vertical axis of the head, and there is a slight upwardly beveled section 31 at the inner upper corner of the wall between the cylindrical surface 30b and the horizontal top face 30a. The outer wall 29 is preferably at an inclination on the order of sixty degrees, and it will be noted that the base of this wall is slightly inwardly oifset with respect to the cylindrical lower portion of the head by approximately its thickness so that an inner ledge 32 is formed.

A cylindrical sleeve 33 is removably seated at one end on the flange 27, with its lower peripheral portion closely contacted by the adjacent vertical flange 28. The sleeve, thus constituting an inner wall coaxial with the frustoconical outer wall, projects above the upper end of the latter and has an outside diameter which is slightly less than the inside diameter of such end. This spacing provides a continuous circular outlet 34 from the burner at which the combustion takes place, as hereinafter described.

At the upper exposed end portion, the removable sleeve 33 has aflixed thereto a deflector section 35 which extends continuously outwardly from about the periphery of the sleeve above and over the horizontal top face of the outer wall 29 of the burner head. This deflector section is of such configuration to comprise, as illustrated, an outboard vertical cylindrical wall 36 which lies within a Vertical projection of the top face 30a of the outer wall, an outboard horizontal surface 37 continuous with the wall 36 at the bottom of the same and extending inwardly therefrom, an inboard vertical cylindrical wall 38 projecting downwardly from the inner margin of the outboard horizontal surface 37, and an inboard horizontal surface 39 extending from the bottom edge of the wall 38 inwardly to the wall of the sleeve 33. The walls 36 and 38 and the horizontal surfaces 37 and 39 of this deflector section are all continuous.

The thus formed deflector section is, moreover, of such relative size and dimension that the outboard horizontal surface 37 is elevated above the top face 30a approximately three times the width of the outlet 34 from the fuel chamber, while the distance between such top face 30a and the inboard horizontal surface 39 is approximately twice the width of such outlet. It will also be seen that this inboard horizontal surface 39 extends outwardly from the outer surface of the sleeve 33 to a point, in cross section, which is approximately at the juncture between the top face 30a and the corner bevel 31. By virtue of these relationships, the continuous passageway about the head for discharge of the gaseous fuel is not only of changing direction, but of outwardly increasing cross-sectional area. More particularly, the initial section, which is formed by the outlet 34, is vertical and of a predetermined width, the escaping gases next proceed through the gap defined by the separation of the inboard deflector surface 39 and top face 30a, while undergoing outward deflection as a result of the projection of the surface 39 over the outlet 34; this gap as noted is twice the size of the initial section 34. Finally, the gases pass through the terminal opening, again enlarged, defined by the outboard horizontal surface 37 of the deflector section and the top face 30a. The shape of the underside of the deflector section will also be seen to accomplish this last enlargement of the passageway, as well as the first, by an upward step.

The sleeve 33, carrying the deflector section constitutes an insert in the burner head which can readily be removed for cleaning. Since this insert is hollow, a thermostatic control unit as earlier mentioned can readily be accommodated. If no such control is to be employed, any suitable form of air plate or baflle can be inserted in the sleeve 33.

The outer wall of the burner in the construction illustrated is supplied with a plurality of vertically aligned orifices 40 adjacent the pilot burner 22 for drawing the flame from the latter therethrough to ignite the main burner. As indicated earlier, however, the pilot arrangement is variable, it being clear that any suitable means of ignition could be employed in lieu of the arrangement I have specifically shown.

By virtue of the described construction, the gaseous fuel chamber in the new burner, that is, between the outer wall and sleeve, has a relatively small volume and, moreover, decreases in width upwardly toward the combustion zone. The supply tube is dropped or downwardly offset from the burner body, and the lower portion of the burner chamber as a result of the lower ledge 32, includes a downwardly and somewhat outwardly located channel which merges gradually with the tube, as shown by comparison of the sections in FIGS. 3 and 4, respectively. This formation of the head, and elimination of the normal space in which the incoming gases might expand, causes the flow of the gases through the new burner head to be smooth, with little, if any, drop in the initial velocity.

A burner in accordance with the illustrated and described construction having a two and one-fourth inch diameter, will operate efficiently over the range of from approximately 500 to 18,000 B.t.u. per hour, whereby this burner has an extremely good turn down ratio on the order of thirty-six to one. FIGS. 5, 6 and 7 illustrate the flame formations produced respectively at low, medium and full flame conditions in a burner of the noted size, wherein the width of the initial outlet 34 is approximately one-sixteenth of an inch and the successive gaps at the steps formed by the surfaces 39 and 37 are on the order of one-eighth and three-sixteenths of an inch respectively. More particularly, the low flame in FIG. 6 represents a minimum flow of from about 480 to 500 B.t.u. per hour. The outer dashed line 41 represents a blue bead, there being no flame cones evident, While the inner dashed line 42 indicates the envelope of the unburned gases. The velocity is, of course, very low, hardly more than seepage, and ignition is maintained at these conditions by virtue of the fact that outlet 34 functions as a relatively 'small vertical port retaining as much gas velocity as possible as well as providing cold vertical walls about the 'slow moving gas to chill it below the ignition point and 'prevent flash-back. This is known as flame quenching and must be provided when velocity through a port is less than the flame front travel of the gas-air mix; a large port would allow the flame to enter the burner head. The deflector section 35 also provides edges or steps to which the flame can and does adhere.

The flame pattern illustrated in FIG. 7 is representative of a medium condition with a flow rate on the order of 1,400 to 5,000 B.t.u. per hour. In this operating condition, the flame comprises an outer cone 43, an inner cone 44, and an envelope 45 indicating the extent of the unburned gases. The velocity is still relatively low, and it will be seen that the first step automatically provides a proper port balance at medium rates on the order indicated, the flame base bridging between the corner defined by the deflector wall 38 and step 39 and top face 30a of outer wall 29.

At full flame conditions as shown in FIG. 8, and representing flow on the order of 12,000 to 18,000 B.t.u. per hour, the flame will be seen to bridge betweentop face ,30a and the step at the junction of the deflector wall 36 and horizontal surface 37, with this last separation thereby providing an effective port approximately three times larger than the control port formed by the outlet 34. The innermost envelope of unburned gases is indicated at 45', the inner cone at 44', and the outer cone by dashed line 43'. The deflector section 35 here fully functions to deflect and control the discharge in such manner as to reduce the velocity below the flame front travel of the hlowest burning gases. Without this effective control, the velocity would be too high to maintain ignition or, in other words, would be greater than the flame travel or ignition value of the gas-air mixture so that the flame would lift from the port and most likely be extinguished.

It will therefore be seen that the deflector section 35 forms an operative continuation of the vertical orifice or outlet 34 cooperably with the top face of the outer wall 29. When this burner is turned on full, the gaseous mixture is of course deflected outwardly and upwardly over the stepped underside of the deflector section and set into local turbulence for entrainment of secondary air. Energy is dissipated in this turbulence tending to lower the velocity of the discharge in this effective terminal port area, and the combustible mixture additionally loses velocity by reason both of the change of direction of the flow which is experienced and the Widening of the passageway as noted previously. As the rate of flow is reduced by the conventional valve control, a point is reached at which the inner ledge or step, in effect, takes over, as shown, for example, by the condition illustrated in FIG. 7, and it has been determined that this point is usually below approximately forty percent of the full rate. At minimum rate, in which the vertical cylindrical outlet is the operative port, the mixture issues in slow and gentle manner, without the turbulence noted at high levels of flow. In this last condition, there is not only the aforenoted chilling of the mixture below ignition value to prevent flash-back into the burner cavity, the inner step against which the flame impinges and clings serves to insulate the bead from rapid conductive loss of heat, which would drop the temperature below the ignition point and accordingly extinguish the flame.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I. therefore, particularly point out and distinctly claim as my invention:

1. A gas burner comprising a head having a vertical axis, laterally spaced apart inner and outer walls forming a ring-like chamber for receiving gaseous fuel supplied to the burner, an inlet in communication with said chamber for the supply of the fuel to the same, the upper end portion of the outer wall having a horizontal top face and an axial interior surface which is cylindrical about the vertical axis of the head, said inner wall having a cylindrical upper end portion extending above said horizontal top face of the outer wall coaxially with said interior surface of the upper end portion of the outer wall and including an axial section opposed thereto in slightly spaced relation, the thus opposed coaxial sections of the outer and inner walls forming a narrow and continuous vertical cylindrical outlet for discharge of fuel from said chamber, and a deflector section extending continuously outwardly from about the periphery of the exposed upper end portion of the inner wall above and over the horizontal top face of the outer wall, said deflector section having an outboard vertical cylindrical wall lying within a vertical projection of the top face of the outer wall, with the underside of said deflector section inwardly from said outboard vertical wall being shaped to define an outboard horizontal surface spaced upwardly from the top face of the outer Wall at a distance approximately three times the width of said vertical cylindrical outlet from the fuel chamber, an inboard cylindrical vertical wall contiguous with said outboard horizontal surface of the deflector section and of a height approximately one-third of the distance between said outboard horizontal surface of said section and the top face of the outer wall, and an inboard horizontal surface extending between said inboard cylindrical vertical wall and the cylindrical upper end portion of said inner wall of the head, the inboard horizontal surface of the deflector section thereby being spaced above the top face of the outer wall of the burner head a distance which is approximately twice the width of the vertical outlet from the fuel chamber, the width of said inboard horizontal surface of the deflector section being slightly greater than the width of said vertical outlet between the coaxial opposed cylindrical surfaces of the outer and inner walls defining said outlet.

2. A gas burner as set forth in claim 1 wherein the portions of the outer and inner walls of the head defining the fuel chamber are shaped so that the chamber has a cross-sectional area which becomes progressively smaller in proceeding upward from the bottom of the head of the fuel outlet at the top.

3. A gas burner as set forth in claim 1 wherein said inlet extends substantially radially outwardly from the burner head.

4. A gas burner as set forth in claim 1 wherein the inner edge of the upper end of the outer wall of the head is slightly beveled outwardly from the vertical cylindrical interior surface to the horizontal top face of the wall.

References Cited by the Examiner UNITED STATES PATENTS 1,158,986 11/15 Cronwall 158-113 1,620,071 3/27 Chappelle 158-112 1,843,361 2/32 Hageman 158-116 X 1,995,003 3/35 MacKenzie et a1. 158-110 2,210,228 8/40 Beckett 158-116 2,348,767 5/44 Walker 158-7 2,587,802 3/52 Abrams 158-113 FOREIGN PATENTS 908,461 9/45 France.

1,077,026 4/54 France.

JAMES W. WESTHAVER, Primary Examiner. MEYER PERLIN, Examiner,

Claims (1)

1. A GAS BURNER COMPRISING A HEAD HAVING A VERTICAL AXIS, LATERALLY SPACED APART INNER AND OUTER WALLS FORMING A RING-LKE CHAMBER FOR RECEIVING GASEOUS FUEL SUPPLIED TO THE BURNER, AN INLET IN COMMUNICATION WITH SAID CHAMBER FOR THE SUPPLY OF THE FUEL TO THE SAME, THE UPPER END PORTION OF THE OUTER WALL HAVING A HORIZONTAL TOP FACE AND AN AXIAL INTERIOR SURFACE WHICH IS CYLINDRICAL ABOUT THE VERTICAL AXIS OF THE HEAD, SAID INNER WALL HAVING A CYLINDRICAL UPPER END PORTION EXTENDING ABOVE SAID HORIZONTAL TOP FACE OF THE OUTER WALL COAXIALLY WITH SAID INTERIOR SURFACE OF THE UPPER END PORTION OF THE OUTER WALL AND INCLUDING AN AXIAL SECTION OPPOSED THERETO IN SLIGHTLY SPACED RELATION, THE THUS OPPOSED COAXIAL SECTIONS OF THE OUTER AND INNER WALLS FORMING A NARROW AND CONTINUOUS VERTICAL CYLINDRICAL OUTLET FOR DISCHARGE OF FUEL FROM SAID CHAMBER, AND A DEFLECTOR SECTION EXTENDING CONTINUOUSLY OUTWARDLY FROM ABOUT THE PERIPEHERY OF THE EXPOSED UPPER END PORTION OF THE INNER WALL ABOVE AND OVER THE HORIZONTAL TOP FACE OF THE OUTER WALL, SAID DEFLECTOR SECTION HAVING AN OUTBOARD VERTICAL CYLINDRICAL WALL LYING WITHIN A VERTICAL PROJECTION OF THE TOP FACE OF THE OUTER WALL, WITH THE UNDERSIDE OF SAID DEFLECTOR SECTION INWARDLY FROM SAID OUTBOARD VERTICAL WALL BEING SHAPED TO DEFINE AN OUTBOARD HORIZONTAL SURFACE SPACED UPWARDLY FROM THE TOP FACE OF THE OUTWR WALL AT A DISTANCE APPROXIMATELY THREE TIMES THE WIDTH OF SAID VERTICAL CYLINDRICAL OUTLET FROM THE FUELD CHAMBER, AN INBOARD CYLINDRICAL VERTICAL WALL CONTIGUOUS WITH SAID OUTBOARD HORIZONTAL SURFACE OF THE DEFLECTOR SECTION AND OF A HEIGHT APPROXIMATELY ONE-THIRD OF THE DISTANCE BETWEEN SAID OUTBOARD HORIZONTAL SURFACE OF SAID SECTION AND THE TOP FACE OF THE OUTER WALL, AND AN INBOARD HORIZONTAL SURFACE EXTENDING BETWEEN SAID INBOARD CYLINDRICAL VERTICAL WALL AND THE CYLINDRICAL UPPER END PORTION OF SAID INNER WALL OF THE HEAD, THE INBOARD HORIZONTAL SURFACE OF THE DEFLECTOR SECTION THEREBY BEING SPACED ABOVE THE TOP FACE OF THE OUTER WALL OF THE BURNER HEAD A DISTANCE WHICH IS APPROXIMATELY TWICE THE WIDTH OF THE VERTICAL OUTLET FROM THE FUEL CHAMBER, THE WIDTH OF SAID INBOARD HORIZONTAL SURFACE OF THE DEFLECTOR SECTION BEING SLIGHTLY GREATER THAN THE WIDTH OF SAID VERTICAL OUTLET BETWEEN THE COAXIAL OPPOSED CYLINDRICAL SURFACES OF THE OUTER AND INNER WALLS DEFINING SAID OUTLET.

Images