US2960157A

US2960157A - Gas burner

Info

Publication number: US2960157A
Application number: US549662A
Authority: US
Inventors: John W Dolby
Original assignee: CONFIGURED TUBE PRODUCTS CO
Current assignee: CONFIGURED TUBE PRODUCTS Co
Priority date: 1955-11-29
Filing date: 1955-11-29
Publication date: 1960-11-15
Anticipated expiration: 1977-11-15

Description

Nov. 15, 1960 w, DOLBY 2,960,157

GAS BURNER Filed Nov. 29, 1955 FIGZ . INVENTOR.

John W Dolby WZj 342107776175 GAS BURNER John W. Dolby, Elgin, Ill., assignor to Configured Tube Products $0., Bellwood, [1]., a corporation of Illinois Filed Nov. 29, 1955, Ser. No. 549,662

Claims. (Cl. 158116) This invention relates to burners for use with a mixture of gaseous fuel and air and pertains particularly to burners made of sheet metal or the like.

Thus, one principal object of the invention is to pro vide a new and improved burner which may be made very economically, principally of sheet metal or other thin material, yet will give outstanding performance when used on a cooking stove or some other heating appliance.

A further object is to provide a burner of the foregoing character which is extremely small in size yet is capable of adequately high heat output.

It is another object to provide a new and improved burner which will provide heat output over an extremely wide range so that the burner may be adjusted to the slowest simmer or the fastest boil or to any desired heat setting therebetween.

A further object is to provide a new and improved burner of the foregoing character which is arranged to prevent the burner flame from backfiring into the burner.

It is another object to provide a new and improved burner of the foregoing character which is arranged to provide an advantageous flame distribution.

Further objects and advantages of the invention will appear from the following description, taken with the accompanying drawings, in which:

Figure 1 is an enlarged elevational view of a sheet metal burner constituting an illustrative embodiment of the present invention;

Fig. 2 is a central elevational sectional view taken through the burner of Fig. 1; and

Fig. 3 is a plan view of the burner of Fig. 1.

If the drawings are considered in greater detail, it will be seen that they illustrate a burner which is shown at about twice its actual size. It will thus beappreciated that the burner is of extremely compact form. Nevertheless, the burner is capable of being adjusted continuously to give a heat output over an extremely wide range extending, for example, between 500 and 16,000 B.t.u.s per hour.

The illustrated burner is made principally of sheet met al and hence may be produced at extremely low cost. The small size of the burner also contributes to its economical construction. It will be seen that the illustrated burner 19 comprises an outer shell 12, generally of inverted cup-shaped form. As shown, the outer shell 12 comprises a two-diameter side wall 14 surmounted by a flat horizontal top wa1l16. The lower end of the shell is formed into a mounting flange 18 which surrounds an axial opening 20- adapted to receive a mixture of fuel and air from a suitable mixing tube or the like. The burner is constructedfor use with all city gases, whether natural, manufactured or mixed, and also for use with liquified petroleum gases including butane and propane.

The illustrated two-diameter side wall 14 comprises a lower portion 22 of relatively large diameter and an up per portion 24 of smaller diameter. An annular, sub- States Patent stantially horizontal shoulder or step 26 is formed between the lower and

upper portions

22 and 24.

To discharge the fuel and air mixture from the shell 12, a multiplicity of main ports '28 are formed through the upper, small diameter portion 24. All of the ports 28 are at the same horizontal level and are spaced at short distance above the shoulder 26. The relation between the shoulder or olfset portion 26 and the ports 28 is such that at low turn down the shoulder forms a pocket which causes the fire from the ports to merge creating, in eifect, a single annular port. This action results in stable operation of the burner at extremely low flow rates.

A multiplicity of secondary ports 30 are formed in the larger diameter portion 22 of the outer shell 12. It Will be seen that the diameter of the secondary ports. is substantially less than that of the primary or main ports 28. The secondary ports 30 are spaced a short distance below the shoulder or step 26.

The flow of fuel-air mixture to the secondary ports 39 is controlled by a generally tubular baflle 32 mounted within the outer shell 12. It will be seen that the tubular bafiie 32 takes the form of a three-diameter inner shell having an upper annular element 34 of relatively small diameter, a lower element 36 of relatively great diameter, and an intermediate annular element 38 of intermediate diameter. A pair of shoulders or

steps

40 and 42 are formed between the intermediate element 33 and the upper and

lower elements

34 and 36.

As illustrated, the upper element 34 is of an outer diameter corresponding to the inner diameter of the smaller portion 24 on the outer shell 12. The element 34 is snugly received within the lower end of the portion 24 so that a gas-tight joint will be formed therebetween. The upper side of the step 40 abuts against the lower side of the step or shoulder 26 so that the inner shell 32 is positively located in the outer shell 12. As shown, the small diameter element 34 has an upper, substantially horizontal annular edge 44 which is adjacent the lower margins of the main ports 28. The inner shell 32 thereby conveniently provides an inwardly extending annular ledge at a level corresponding generally to that of the lowermost extremities of the ports 28. The annular ledge or edge 44, when located as shown in Fig. 2, tends to have a lowering or depressing effect on the path of the fuel-air mixture as it passes outwardly through the ports 28, so that the mixture travels outwardly at a smaller upward angle than it would in the absence of the ledge 44.

The width and elevation of the ledge 44 affect the angle of the flame. In general, the lowering effect on the flame tends to be increased as the ledge 44 is made higher relative to the lower'extremities of the ports 28. In other words, raising the ledge increases the lowering or depressing effect on the flame.

It will be seen that the large diameter lower element 36 of the inner shell 32 corresponds in outer diameter to the inner diameter of the lower portion 22 on the outer shell 12. The portion 36 is snugly received within the portion 32 so as to form a gas-tight joint therebetween. The inner shell 36 may be secured within the outer shell 12 in any suitable manner, as by spot or seam Welding, as indicated at 48 in Fig.2.

The intermediate portion 38 of the inner shell 32 is of an outside diameter greater than that of the smaller portion 34 but less than the inside diameter of the lower portion 22 on the outer shell 12. Thus, an annular space 50 is defined between the intermediate portion 38 and the cylindrical portion 22 of the outer shell 12. A plurality of metering ports 52 extend through the intermediate portion 38 to admit the fuel-air mixture to the space 50. It will be seen that the metering ports 52 are small in size and few in number so as to restrict the flow of mixture into the space 50. The metering ports 52 are at a substantially lower level than that of the secondary discharge ports 30. The arrangement ofthe

wall portions

22 and 38 and the

ports

30 and 52 is such as to prevent backfiring through the secondary ports 30. If any flame travels back through one of the ports 30, it will be extinguished by the cool inner wall portion 38 and will not be propagated through the space 50 into the interior of the

shells

12 and 32. The provision of the space 50 and the arrangement of the

ports

30 and 52 stabilizes the flames at the secondary ports 30. The flames at the secondary ports stabilize the main flames at the main ports 28, particularly at high rates of flow. In particular, the secondary flames prevent the main flames from being blown away from the main ports 28.

To direct the fuel-air mixture through the main ports 28 and prevent backfiring therethrough, the burner is provided with an additional baifling member 54 which may assume various forms, but, as shown, is generally of inverted cup-shaped form. Thus, the baffle 54 comprises a fiat substantially horizontal upper wall 56 which is secured to the underside of the top wall 16 on the outer shell 12. One or more spot welds 58 may be formed between the walls 16 and 56 to hold the baffle 54 in place. The baflle 54 also includes an annular, substantially cylindrical side wall or flame 60 which extends downwardly in depending relation to the upper wall 56. It will be seen that the annular side wall 60 is concentric with but spaced inwardly from the upper side wall portion 24 on the outer shell 12. The annular wall 60 extends downwardly so that it will at least partly overlap the main ports 28. It will be understood that the exact level of the edge 62 may be varied to a certain extent, with some effect upon the angle of the flames at the ports 28. As illustrated in Fig. 2, the spacing between the baffle wall 60 and the wall 24 of the shell 12 is comparable to the size of the main ports 28, and is a minor fraction of the diameter of the baflle.

The annular baflle wall 60 substantially prevents backfiring of the flames through the ports 28. If any flame travels inwardly through one of the ports 28, it will be extinguished by the cool depending flange 60. Thus, the flame will not be propagated into the interior of the outer shell 12. The ledge 44 and the depending flange 60 cooperate to increase the efiective depth of the main ports 28.

Another important effect of the baflle 54 is to regulate the direction or angularity of the flames at the main ports 28. Generally, the lower edges of the baffle 54 cooperate with the upper extremities of the main ports 28 to determine the angularity of the upper portions of the main flames. Thus, varying the elevation of the lower edges of the baflie 54 will change the angle of the flames. Lowering the lower edge of the baflle will tend to deflect the flames upwardly so that they will make a higher angle to the horizontal. On the other hand, raising the lower extremity of the baffle will tend to lower the angle of the flames.

Thus, the direction of the flames at the main ports 28 can be varied to a considerable extent by changing the elevation of the lower edge of the baffle 54 and the upper edge 44 of the baffle element 34. In the illustrated construction, the upper edge or ledge 44 is at substantially the same elevation as the lower extremities of the main ports 28. The lower edge 62 of the bafile 54 extends downwardly below the elevation of the upper extremities of the ports 28 and generally is at the elevation of the axes of the ports. This arrangement results in main flames which are directed upwardly at a small angle to the horizontal and tend to curl upwardly as they travel outwardly. The general shape of the flame is indicated by a flame pattern 64 in Fig. 2.

To spread the flames and control this upward curling eflect, the burner is provided with a flame spreader 66 mounted on the top of the outer shell 12. While the flame spreader 66 might readily be made in one piece, it is made in lower and

upper parts

68 and 69 in the illustrated construction. It will be seen that the lower part 68 is made of sheet metal and is generally cup or disk shaped. It has a lower wall 70 which is welded or otherwise secured to the upper wall 16 of the outer shell 12. The diameter of the lower wall 70 corresponds roughly but is illustrated as being slightly less than that of the wall 16. A downwardly tapering frusto-conical side wall 72 extends upwardly from the lower wall 7 0.

In this instance, the upper part 69 of the flame spreader 66 is in the form of a disk-like member having an upper portion 74 which is supported on the upper edge of the side wall 72 and projects outwardly in overhanging fashion therefrom. As illustrated, the disk-like part 69 has a downwardly projecting lower portion 76 which is received in the upper end of the disk-shaped lower part 68. It will be seen that the projecting lower portion 76 is downwardly tapered in conformity with the shape of the side wall 72. As illustrated, the upper part 69 is merely retained by gravity in the lower part 68, but, of course, the two parts may be suitably welded or otherwise secured together.

The upwardly flaring side wall 72 and the overhanging portion 74 of the disk 69 tend to spread the main flames outwardly so that they will engage a large area on any kettle or pot placed above the burner.

When there is no cooking utensil over the burner, the action of the flame spreader 66 is particularly important in controlling the upward curl of the main flames. With a large kettle or pan over the burner, the bottom of the pan directs the flames outwardly so that they travel along a maximum area on the pan. Thus, the pan has a spreading effect on the flame. In other words, the flames tend to change in shape to adapt themselves to the size and shape of the pan.

When the burner is turned on to extremely low levels, the spreader 66 spreads the heat from the flames outwardly so that the heat is directed to the outer edges of the pan and is not concentrated at the center. This arrangement prevents scorching of food at low levels of heat output. With the present burner, it is thereby possible to cook foods at low turn down directly over the flame rather than using a double boiler.

While the operation of the burner has already been completely described, it may be helpful to offer a brief summary. At high rates of fuel flow through the burner 10, both the main ports 28 and the secondary ports 30 support flames. The ledge 44 and the lower edge 62 of the baflie 54 cooperate to direct the main flames upwardly and outwardly from the main ports 28 at an angle to the horizontal. The outer ends of the main flames tend to curl upwardly, but this curling eflect is controlled by the flame spreader 66. When there is no pan or the like over the burner, the flame spreader 66 has its maximum effect. The apparatus of the main flames is greatly improved by the flame spreader. With a small pan over the burner, the flame spreader 66 directs the flames outwardly so that they will engage the outer portions of the pan. Larger pans, when placed over the burner, have a further spreading eflect, with the result that the flames travel outwardly along the bottom of the pan and thereby engage a maximum area on the pan. At low turn downs, the flame spreader distributes the heat from the burner and prevents scorching of food.

At high rates of fuel flow, a separate flame is maintained at each of the main ports 28. The maximum heat output of the burner is adequately correct for any cooking operation such as rapidly bringing water to a boil. For example, a heat output of 16,000 B.t.u.s is readily obtained.

As the rate of fuel flow is turned down, the size of the flames at the ports 28 is decreased until all of the main flames-eventuallymerge into a single ring of flame encircling the ports 28. Thus, the main ports 28. effectively constitute a single annular port at low rates of flow. In this way, the operation of the burner is greatly stabilized at low levels. At the minimum rate of fuel flow, the flames at the secondary ports 30 will go out. Any small amount of fuel that may issue from the secondary ports will be consumed in the flame at the main ports.

It will be apparent that a substantially continuous rate of heat output is obtained between extremely high and extremely low levels. The flame at the main ports is maintained in a stable condition downto a flow rate of 500 B.t.u.s per hour, for example. The burner may be adjusted to an extremely high level to bring water to a boil, an extremely low level for keeping food warm or directly cooking easily scorched foods normally requiring the use of a double boiler, or to any intermediate level such as one suitable for frying. Backfiring of the flames through the main ports 28 is prevented by the baffle 54 which cools and thereby extinguishes any flame that may travel inwardly through the ports 28.

Since the burner is, made principally of sheet metal and is of extremely small size, it is unusually economical in construction. Nevertheless, its performance on a cooking stove is outstanding in every way, particularly with regard to maximum heat output, minimum heat output and the continuity of the intermediate range of heat outputs.

Various modifications, alternative constructions and equivalents may be employed without departing from the true spirit and scope of the invention as exemplified in the foregoing description and defined in the following claims.

-I claim:

1. In a burner, the combination comprising an outer shell having a generally annular side wall surmounted by a top wall, said side wall having an upper portion of relatively small diameter and a lower portion of greater diameter with a shoulder therebetween, a plurality of angularly spaced main ports extending through said upper portion, a plurality of angularly spaced secondary ports extending through said lower portion, a generally tubular inner shell received within said outer shell, said inner shell including an upper relatively small diameter element, a lower relatively large diameter element, and an intermediate element therebetween, said upper element being snugly received within said upper portion and having an upper bafliing edge portion adjacent the lower margins of said main ports, said lower element being snugly received within said lower portion substantially below said secondary ports, said intermediate element being spaced inwardly from said lower portion and thereby being effective to define an annular space therebetween, said secondary ports communicating with said annular space, a plurality of spaced ports ex tending through said intermediate element and communieating with said space, and a generally cylindrical annular baflle dependingly mount-ed on said top wall in inwardly spaced relation to said upper portion, the spacing between said bafiie and said upper portion being a minor fraction of the diameter of said baffle, said annular baffle having a lower edge portion generally at the level of said main ports and in inwardly spaced relation thereto to prevent backfiring through said ports.

2. In a burner, the combination comprising an outer generally inverted cup-shaped shell having an annular side wall surmounted by a top wall, said side wall having an upper portion of relatively small diameter and a lower portion of greater diameter with a shoulder therebetween, a plurality of angularly spaced main ports extending through said upper portion at a level above said shoulder, a plurality of angularly spaced secondary ports extending through said lower portion at a level below saidshoulder, a generallytubular inner shell re' ceived within said outer shell, said inner shell including an upper relatively small diameter element, a lower relatively large diameter element, and an intermediate element of intermediate diameter, said upper element being snugly received within said upper portion and having an upper baffling edge adjacent the lower margins of said main ports, said lower element being snugly received within said lower portion substantially below said secondary ports, said intermediate element being substantially concentric with but spaced inwardly from said lower portion and thererby being effective to define an annular space therebetween, said secondary ports communicating with said annular space, a plurality of angularly spaced metering ports extending through said intermediate element and communicating with said space, an annular generally cylindrical bafie dependingly mounted on said top wall in concentric and inwardly spaced relation to said upper portion, the spacing between said baflie and said upper portion being a minor fraction of the diameter of said baffle, said annular baffle having a lower edge portion partly overlapping said main ports in inwardly spaced relation thereto to prevent backfiring through said main ports, and an upwardly flaring flame spreading member fixed on said top wall.

3. In a burner, the combination comprising an outer shell generally ofinverted cup-shaped form and having an opening for receiving a. mixture of fuel and air, said outer shell having a side wall surmounted by a top wall, saidside wall including a lower generally cylindrical relatively large diameter portion and an upper generally cylindrical relatively small diameter portion with an annular shoulder therebetween, said upper portion having a plurality of angularly spaced main ports extending therethrough adjacent but spaced above said shoulder, said lower portion having a plurality of angularly spaced secondary ports therethrough adjacent but spaced below said shoulder, a generally tubular baffle received within said shell, said baflle having a relatively small diameter upper element received snugly within said upper portion of said shell and having an annular upwardly facing edge generally at the level of the lower margins of said main ports, said baffle having an intermediate element spaced inwardly from said lower shell portion, said intermediate element defining an annular space between said intermediate element said said lower shell portion, said secondary ports extending outwardly from said space, said baflle having a lower relatively large diameter element snugly received within said lower shell portion and spaced below said secondary ports, said baflie having a plurality of ports extending therethrough into said annular space, a second battle of inverted cup-shape and having a top wall mounted on the underside of said top wall of said shell, said second bafile having a generally cylindrical side wall depending from said top wall thereof and spaced radially inwardly from said upper portion of said shell in coaxial relation thereto, the spacing between said baffle and said upper portion being a minor fraction of the diameter of said baffle said side wall of said second baflle having a lower annular edge generally at the level of said main ports to inhibit backfiring therethrough.

4. In a burner, the combination comprising an outer sheet metal shell generally of inverted cup-shaped form and having an opening in its lower end for receiving a mixture of fuel and air, said outer shell having a twodiarneter side wall surmounted by a flat horizontal top wall, said side wall including a lower cylindrical relatively large diameter portion and an upper cylindrical relatively small diameter portion with an annular shoulder therebetween, said upper portion having a plurality of horizontally alined radial main ports extending therethrough adjacent but spaced above said shoulder, said lower portion having a plurality of angularly spaced horizontally alined radial secondary ports therethrough adjacent but spaced below said shoulder, each of said secondary ports being substantially smaller than each main port, a generally tubular three-diameter sheet metal baffle received Within said shell, said baffle having a relatively small diameter upper element received snugly within said upper portion of said shell and having an annular upwardly facing edge substantially at the level of the lower margins of said main ports, said baflie having an intermediate element of greater diameter than said upper element but of less outer diameter than the inner diameter of said lower shell portion, said intermediate element defining an annular space between said intermediate element and said lower shell portion, said secondary ports extending outwardly from said space, said bafiie having a lower relatively large diameter element snugly received within said lower shell portion and substantially spaced below said secondary ports, said bafiie having a plurality of angularly spaced metering ports extending through said intermediate element into said annular space, a second inverted cup-shaped bafiie having a flat top wall mounted on the underside of said top wall of said shell, said second baffle having a substantially cylindrical sidewall depending from said top wall thereof and spaced radially inwardly from said upper portion of said shell in coaxial relation thereto, the Spacing between said bathe and said upper portion being a minor fraction of the diameter of said bafile, said depending side wall having a lower annular edge substantially at the level of the axes of said main ports.

5. In a burner, the combination comprising a shell having an opening therein for receiving a mixture of fuel and air, said shell having a top wall and a-generally cylindrical side wall extending downwardly therefrom, a plurality of spaced generally circular ports extending through said side wall and disposed therearound in a substantially horizontal row, means inside said shell defining an annular ledge extending inwardly from said side wall substantially at the level of the lower margins of said ports, and a depending baflle mounted on said top wall Within said shell and concentric with said side Wall, said bafile extending downwardly below the level of the upper margins of said ports and being closely spaced inwardly from said side wall by an amount corresponding generally to the diameter of said ports so that said bafile and said ledge will cooperate to prevent backfiring through said ports.

References Cited in the file of this patent UNITED STATES PATENTS 365,606 Kline June 20, 1887 2,001,611 Ipold May 14, 1935 2,142,418 Stocker Jan. 3, 1939 2,155,339 Stoll Apr. 18, 1939 2,215,176 Forster Sept. 17, 1940 2,220,247 Kochendorfer et al Nov. 5, 1940 FOREIGN PATENTS 518,289 Germany Feb. 14, 1931