US3042110A - Top surface burner for gas range - Google Patents

Description

July 3, 1962 v. WEBER ETAL TOP SURFACE BURNER FOR GAS RANGE 3 Sheets-Sheet 1 Filed Dec. 16, 1957 INV EN TORSI Vi'rlor Wabaand. BY (Izarlesflflrmsm.

ATTDM July 3, 1962 v. WEBER ETAL 3,042,110

TOP SURFACE BURNER FOR GAS RANGE Filed Dec. 16, 1957 3 Sheets-Sheet 2 INV EN TORI Viaor Weber and (barlesflEansazz .AWUEEK July 3, 1962 v. WEBER ETAL 3,042,110

TOP SURFACE BURNER FOR GAS RANGE Filed Dec. 16, 1957 3 Sheets-Sheet S [NV E NTORS. Vida! WZ M and (fiarlesfiflansan.

United States This invention relates generally to burners for gaseous fuels and more particularly to thermostatically controlled top surface burners for cooking ranges.

One difliculty that has been experienced in thermostatically controlled top surface burners for cooking ranges is that of eflicient heating. Since the sensing means of the thermostat is best installed within the ring of the burner, the diameter of the burner ring of necessity becomes relatively large thereby moving the flame toward the outside edges of the bottom of any cooking vessel placed upon the burner. This tends to lower the heating efliciency of the burner since it permits less intimate and complete contact between the flame and the bottom of the cooking vessel.

Another difliculty encountered in burner design is the prevention of flashback (ignition occurring at the orifice in the venturi). Flashback has a marked tendency to occur when the ratio of port length to cross-sectional area is too low.

In the case where standing pilots are used, another difficulty encountered in the design of burners for use with thermostatically controlled means is poor ignition at low inputs when the control valve is just throttling. The design must be such that ignition will occur all the way around the burner at low inputs. Otherwise, raw gas will be allowed to escape into the air around the range.

Many burner installations of this type employ a bypass around the thermostatically operated valve. In these cases, it is highly desirable to have the by-pass adjustment as low as possible to attain low temperatures in the cooking vessel and to provide burner ignition by the conventional flash tube to eliminate the heat input of a standing pilot from the burner location. Since the flash tubes do not ignite well with extremely low burner inputs, very stable burning is necessary at the burner.

Another difliculty encountered in installations of this type is the design of a burner body so that it may be easily and inexpensively manufactured. In order to eliminate the need for drilling, which is a relatively highcost manufacturing operation, and to provide a burner body that may be manufactured by a relatively inexpensive diecasting operation, it is necessary to design the burner body so that metal cores that can be pulled from the finished casting may be used.

It is an object of the invention to achieve high efliciency in heating in a burner installation of the aboveindicated character without decreasing the port length to the point at which flashback is encountered.

Another object of the invention is to prevent flashback in a burner installation of the above-indicated character.

Another object is to insure stable burning in a burner installation of the above-indicated character at low inputs.

Another object is to prevent the upward draft of air around the top surface burner of a gas range from washing the gas away from the burner ports before it can be burned.

Another object of the invention is to minimize the heat loss from the port ring of a burner installation of the above-indicated character in order to assist steady burning at low inputs.

Another object of the invention is to space the ports of a burner installation of the above-indicated character to atent "ice produce a condition that will insure complete ignition at low inputs to the burner.

Another object of the invention is to design an inexpensive and easily manufactured burner body for a device of the above-indicated character.

In the preferred embodiment of the invention, the burner body is ring-shaped so that the sensing element of the thermostat may be positioned within the central opening of the burner. The burner body has an annular opening in its top in which a ring of low heat conductivity is positioned. The burner port ring is mounted on the low heat conductive ring to form the burner ports therewith. The port ring also has an extension which forms an inner seal with the burner body. Stable burning at low inputs is accomplished by (1) providing flange-like projections on the port ring and burner body so as to prevent any upward draft of air from carrying the gas away from the ports before it is burned, (2) providing an additional port in the burner ring which has considerably improved flame stability and which provides ignition for the other ports, and (3) holding the temperature of the port ring high by the use of the ring of low heat conductivity.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein a preferred embodiment of the invention is illustrated by way of example.

In the drawings:

FIG. 1 is a plan view of the preferred embodiment of the invention installed in a gas range;

FIG. 2 is a partial cross-sectional view taken along line IIII of FIG. 1;

FIG. 3 is an elevational view partly in cross-section of the arrangement shown in FIG. 1;

FIG. 4 is a fragmentary view in elevation of a detail;

and

FIG. 5 is an enlarged view taken on line VV of FIG. 4.

Referring more particularly to the drawings, the top surface burner illustrated therein includes a conventional grate 10 and reflector pan 12 mounted horizontally on a range top 14. The reflector pan has a central opening 16 in which is mounted the burner head 18 of the burner. The diameter of central opening 16 is large enough to provide an annular secondary air port 19 for ventilating the burner head.

The burner includes a body 20 having a vertical, circular inner wall 22 and an outer wall 24. Inner wall 22 has a cylindrical top portion 23. The internal diameter of inner Wall 22 forms a central opening in body 20. Outer wall 24 has a generally annular top portion 26 which is contiguous with the top portion 23 of inner wall 22 and forms an annular passageway 28 in the top of the body 20. The remaining portion of the outer wall 24 slopes downwardly and outwardly as shown in FIG. 3 to a point at which the bottoms of the inner and outer Walls 22, 24- are in the same horizontal plane.

A venturi and mixing tube 30, having communicating horizontal and vertical tube portions, is attached at the top of its vertical portion to the bottom of body 20 by means of a conventional adapter plate 32. Adapter plate 32 is mounted on body 20 by screws 34, 36 which engage threads in flange portions 38, 40, respectively, on body 20. Plate 32 is joined by means of screws 34-, 36 to body 20 and a gasket 42 seals the joint therebetween. An air-tight fitting 44 is provided in adapter plate 32 for tube 30. Gasket 42 contains a port 46 surrounding the opening in the top end of the vertical portion of tube 30. Hence, the port 46 acts as an inlet port for the flow of gas from tube 30 into body 20.

The top portion 26 of outer wall 24 has horizontal annular recess 48 on its internal diameter. An annular, cup-shaped ring 50 of low conductivity is supported on recess 48 with the side wall portion 52 of ring 50 resting thereon so that the base portion 54 of ring 54 is in a. horizontal plane above the top plane of burner body 26.. The top of sidewall portion 52 cooperates with recess 48 to tr'orm a gas seal therewith. Base portion 54 has a central opening 56 therein, the diameter of which is greater than the internal diameter of inner wall 22 of body 20 for a purpose to be hereinafter described.

An annular port ring 58 is horizontally mounted on base portion 54 of ring 50 by supporting an annular rib portion 60 of the port ring 58 thereon. The internal diameter of rib portion 60 is preferably the same as the diameter of central opening 56 in base portion 54, and the width of rib portion 64 is approximately equal tothe width of base portion 54. Rib portion 60 has a plurality of open-ended port slots 62 spaced in a horizontal plane around the periphery thereof extending the full width of the rib portion and facing the base portion 54 so as to define a plurality of burner ports 63. The side wall portions of slots 62 are parallel to each other and the roof is slanted upwardly and outwardly from the internal diameter of rib portion 60. Hence, the burner ports 63 will slightly diffuse the jet of gas issuing therefrom and direct it more quickly toward the cooking vessel bottom which results in more efficient heating. Flashback is prevented by maintaining a suflflcient port length to crosssectional area ratio.

Port ring 58 has a cylindrical extension 64 at its inner portion which extends vertically downward from the main body portion. Extension 64 is positioned within inner wall 22 of the burner body 20 and is so sized that its outer diameter forms a high restriction seal against the internal diameter of inner wall 22. The cylindrical extension 64 of port ring 58, the ring 50, and gasket 42 cooperate with burner body 20 to define a burner chamber 66. Inasmuch as the outer diameter of the cylindrical extension 64 is less than the diameter of the central opening 56 in ring 50, burner chamber 66 has an annular outlet passageway 68.

The outer portion of port ring 58 is provided with an annular flange 70 extending horizontally outwardly of the port ring 58 above the rib portion 69. The top portion 26 of outer wall 24 of the burner body 20 also has an annular flange 72 disposed opposite annular flange 70 beneath the gas outlet ports 63.

' As is illustrated in FIGS. 4 and 5, rib portion 60 is also provided with a small additional port 73 in the form of a drilled hole. Preferably, port 73 is slightly higher than the top plane of the burner ports 63 so that it would have a more favorable feed condition at low flows than the burner ports 63.

Communicating with the horizontal portion of vcnturi and mixing tube 30 is a conventional air shutter 74 for controlling the mixing of the primary air with the gas.

Thermostatic means are provided for controlling the flow of gas to the venturi and mixing tube 30 in response to the temperature of the cooking vessel. A conventional thermostatic valve 76 is set at a desired temperature by means of a control knob 78. A thermal sensing element 80, which is responsive to the temperature of the cooking vessel, is operative to close the valve 76 when the temperature of the cooking vessel reaches that set by knob 78 by causing an expansion of an expansible fluid in tube 82 which in turn controls the valve 76. The sensing element 80 is mounted within the central opening in burner body 20 by any suitable means, such as plate 84, so that element 80 contacts a cooking vessel placed on grate 10.

In the operation of the embodiment of the invention disclosed, the burner gas enters thermostatic valve 76 from an inlet tube 86 which communicates with a supply of gas. The gas then passes into the air shutter 74 where it is mixed with the primary air. The mixture of gas and air then passes through the venturi and mixing tube 30 into burner chamber 66. The mixture of gas and air leaves burner chamber 66 by way of annular outward passageway 68 and passes into the burner ports 63 and burning takes place at the port outlets.

The burner ports 63 are so spaced that at very low gas flows there is a merging or mixing between the gas streams from the individual ports so as to form an almost continuous ring of gas around the burner head outside the ports and within the oppositely disposed flanges 7t and 72. Hence, it will be apparent that flanges and 72 actually define an annular ignition chamber therebetween. These flanges are eflective to accumulate the gas in this ignition chamber at low gas flows and prevent the gas from being carried away from the burner ports 63 by air currents until the gas is ignited. It has been found that 54 to 60 ports or slots of inch width and equally spaced give proper spacing for good ignition if the flanges 70 and 72 are provided.

Port 73 also aids in causing steady and stable burning at low inputs. Because port 73 has more favorable feed conditions, it offers considerably improved flame stability than the other ports. Since the ports are so spaced that at low gas flows there is a merging between the gas streams from the individual ports, port 73 provides ignition for the other ports to prevent the escape of gas into the ambient air under low inputs to the burner.

When the supply of gas is throttled down to a point at which there is insufiicient gas issuing from all of the ports around the periphery of the burner head to sustain a steady flame completely around the burner head, there may be enough gas issuing from port 73 to sustain a steady flame thereat. This steady flame will in turn ignite several of the ports 63 in the immediate region of port 73 so that there is steady burning in the region of the port 73 because of the concentration of outflowing gas in this region. This concentration of outflowing gas is a result of several factors. Firstly, there is a greater burner port area in this region because of additional port 73. Secondly, there are more favorable feed conditions to this region because of the location of port 73. Thirdly, the temperature of the burner ring in this region will be higher because a steady flame is maintained in this region while the flame will be extinguished for temporary periods at the other regions of the periphery remote from the additional port 73. Hence, it will be apparent that the flame coming from burner chamber 66 will be'attracted to the region with the highest temperature.

During the operation of the burner under this condition where a steady flame is maintained only in the region immediate said additional port means 73, the gas issuing from the unlighted ports around the periphery of the burner ring will be accumulated in the annular ignition chamber between flanges 70 and 72. When a sufficient amount of gas is accumulated, it will be ignited by a flame travelling around the burner in a Well known manner from the steady flame region in one direction or another depending on the draft conditions in the area of the burner. As the amount of gas issuing'from the regions on the periphery remote from the additional port 73 is insuflicient to sustain a flame, the flame travelling around the burner will be extinguished after the accumulated gas is burned. When a suflicient amount of gas is subsequently accumulated, the travelling flame will again be effective as above described. Hence, there will be little or no unburned gas escaping into the medium around the burner.

Ring 50 is preferably made of aluminum coated steel. The aluminum protects the steel from corrosion and the steel, by virtue of its low heat conductivity, minimizes the loss of heat from port ring 58.

It will be apparent that the use of parts such as ring 50 and port ring 58 in the construction of the burner makes it possible to manufacture the burner body 20 by using metal cores which can be pulled from the finished casting. The fact that the cores can be pulled makes it possible to make the burner body 20 by the die-casting process, which is a relatively low-cost manufacturing process. Ring 50 and port ring 58 also lend themselves to low-cost manufacturing methods. Ring 50 can easily be formed by stamping and port ring 58 can be die-cast.

FIG. 2 shows a standing pilot 88 which is used in those installations not equipped with a by-pass. In this type of installation, the thermostatic valve may completely throttle the flow of gas to the main burner and, upon opening, may supply only very small flows of gas which must be re-ignited by the standing pilot. It is this condition which requires good ignition characteristics in the burner.

From the foregoing description, it is apparent that stable burning at low inputs has been achieved by the use of protective flanges 70 and 72, the additional port 73, and ring 50. Protective flanges 70 and 72 prevent the upward draft of air around the burner from washing the gas away from the burner ports 63 before it can be burned. The resistance to heat conductance of ring 50 helps to hold the temperature of the port ring 58 high which materially improves steady burning at low inputs. The resistance to heat flow provided by the arrangement can be a combinaion of the lower conductivity of the material of which port ring 58 is made and the resistance to heat flow afforded by the joint between port ring 58 and burner body 20 or it can only be the resistance of the joint. It has been found that aluminum, which is a good heat conductor, can be used in the ring '50 since the resistance to heat flow of the joint is so high. While these features are essential for stable burning at low inputs, they offer little or no hindrance at high inputs when the velocities of the gas-air mixture coming from the burner ports 63 is high. At high input, the burning occurs outside the flanges 70, 72 so that their eflect is nil It is to be understood that although only one embodiment of this invention has been shown and described, the invention can be variously embodied and changes may be made in the construction and arrangement of the parts without departing from the scope of the invention as defined by the appended claims.

We claim:

1. In a burner assembly, the combination comprising a burner body having spaced annular inner and outer walls defining an inlet passageway therebetween, a supporting ring carried by an upper portion of said outer wall, an annular burner head having an annular rib memher on the undersurface thereof resting on said ring for supporting said burner head thereon, said rib member having means cooperating with said ring to define a series of burner ports, a cylindrical member extending downwardly from said burner head for engagement with an upper portion of said inner wall, said supporting ring being spaced from said cylindrical member to define an outlet passageway therebetween for a flow of gaseous fuel from said inlet passageway to said series of burner ports, an annular flange extending outwardly from said burner head and being spaced above said series of burner ports, and an annular projection on the outer wall of said burner body being disposed below said series of burner ports and cooperating with said annular flange to define an accumulation chamber therebetween for unburned gaseous fuel, said annular projection being larger than said annular flange to direct an upward flow of air past the accumulation chamber, and means on said rib member defining an additional port spaced above and between a pair of said series of burner ports, said additional port communicating with said outlet passageway to provide sufiicient gaseous fuel for maintaining a flame in the area of said additional port.

2. In a burner assembly for maintaining a flame at a surface cooking device, the combination comprising a burner body member having annular inner and outer walls defining an inlet passageway for receiving a gaseous mixture of fuel gas and primary air, spaced upper portions on said inner and outer walls defining an annular chamber therebetween, an annular recess means on the interior of the upper portion of said outer wall, a generally cup-shaped ring mounted on said annular recess means and having a portion extending partially across said annular chamber, an annular burner head having a cylindrical extension engaging the exterior of the upper portion of said inner wall, said cup-shaped ring portion terminating in spaced relationship to said cylindrical extension to define an outlet passage therebetween, an annular rib on the undersurface of said burner head resting on said cup-shaped ring portion to support said burner head thereon, a series of open-ended slots in said annular rib cooperating with said cup-shaped ring portion to define a series of burner ports in communication with said outlet passageway, a radially outwardly extending flange member on said burner head disposed above said series of burner ports to accumulate unburned portions of the gaseous mixture, an annular flange on the top portion of said outer wall cooperating with said flange member to define an accumulation chamber therebetween extending radially outwardly a distance greater than said flange member whereby a flow of secondary air about said outer wall passes the accumulation chamber, and an ignition port means extending through said rib member above and between a pair of said series of burner ports and being in 7 communication with said outlet passage to provide a suflicient flow of the gaseous mixture to maintain a flame in the area of the ignition port means.

References Cited in the file of this patent UNITED STATES PATENTS 1,416,500 Nicolaus May 16, 1922 2,402,997 Grayson July 2, 1946 2,456,864 Cole Dec. 21, 1948 2,490,885 Reeves Dec. 13, 1949 2,590,948 Du Perow Apr. 1, 1952 2,611,358 Taylor Sept. 23, 1952 2,843,199 Broddeck et al July 15, 1958 2,854,069 Jensen Sept. 30, 1958 2,860,696 Reinhart Nov. 18, 1958 2,898,979 Hollman et al. Aug. 11, 1959 FOREIGN PATENTS 10,638 Netherlands Nov. 17, 1923

Images