US2855033A - Industrial gas burner - Google Patents

Description

Oct. 7, 1958 A A. FURczYK INDUSTRIAL GAS BURNER Filed oct. s, 1955 ATTORNEY INDUSTRIAL GAS BURNER Alfons A. Furczyk, Wyncote, Pa., assignor to Selas Corporation of America, Philadelphia, Pa., a corporation of Pennsylvania t Application October 3, 1955, Serial No. 538,051

3 Claims. (Cl. 158-109) The present invention relates to radiant cup type industrial gas burners, and more particularly to gas burners of the nozzle mix type in which the fuel and air are mixed as they are being discharged into the combustion space.

In previous burners of the type to which this invention relates, it has been customary to discharge the jets of fuel gas and air in a substantially radial direction into the burner cup. Such a construction necessitated that the tip of the distributor member for the gas and a-ir project somewhat into the cup. This has proved to be undesirable in some furnaces because wide variations in temperature produced stresses in the distributor tips sufficient to cause them to have an uneconomically short life. Furthermore, if a tip should break oi, as they occasionally do, the uncontrolled flow of air or gas through the burner with the broken tip can upset the air-gas ratio to all of the burners supplied as a group.

The burner of the present invention has a `distributor member that is so designed and located relative to the cup that the fuel and air are moved outwardly along the surface of the cup by a combination of centrifugal force and the flow characteristics of a gas. The distributor is ilush with or retracted within the base of the burner cup so that it is removed from the hottest zone. It can, therefore, be made of relatively inexpensive materials.

It is an object of the invention to provide a radiant cup type, nozzle mixing burner in which an even intensity of incandescence is obtained over the entire surface of the cup. It is a further object of the invention to provide a nozzle mix burner that has a long, trouble free life even when used in a furnace that has widely lluctuating temperatures.

United States Patent O Another object of the invention is to provide a' burner of the nozzle mix type which is so designed that even if the tip is broken, the ow of gas and air therethrough will not upset the ratio of other burners supplied from the same manifolds.

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

In the drawings:

Fig. l is a section view of the burner;

Fig. 2 is an end view of the distributor looking from the left in Fig. l;

Fig. 3 is a section on line 3--3 of Fig. 2; and

Fig.p4 is a section through another embodiment of the t invention.

Referring to Fig. l of the drawing, there is shown y the refractory 1 of a furnace wall that is provided with 2,855,033 'I Patented Oct. 7, 1958 ICC in the furnace wall and forms a part thereof. This block is provided with a cup shaped depression 4 on the face thereof, and a concentric opening 6 extending from the `base of the cup to the opposite face of the block. A well tile 5, that may vary in length depending upon the thickness of the furnace wall, extends between the back of block 3 and metal backing 2. This well tile and the backing are each provided with an opening concentric with opening 6 and through which the fuel and air distributing portion of the burner extends. The distributing portion is supported by a metal ring 7 that is welded to the backing around the opening therein.

The distributing port-ion of the burner includes a tubular element 8 made of some material such as cast iron, although it is preferable to have the end 9 nearest the furnace chamber of a heat resisting alloy. Element 8 is of such length that it terminates with its forward end even with the base of cup 4, as shown, or slightly below the base end in opening 6. A flange 11 is provided on the opposite end of the element through which Vbolts 13 extend into a back casting 12, to hold the element and casting rigidly together. The distributing portion of the burner is held 4in position by bolts 14 extending through complementary flanges on ring 7 and back casting 12. It is noted that a suitable refractory cement 15 is used to ll the space between ring 7 and element 8.

Back casting 12 forms a chamber through which air is introduced to the burner by a pipe 16. Fuel gas is supplied to the burner by a pipe 17 that is threaded into a plate 1S closing the back of the casting 12. This plate also has threaded into it,rfrom the opposite side, a second tubular element 19 that forms a passage for the gas as it ows to a distributor member 21 which is mounted on the other end of element 19. Elements 8 and 19 may vary in length depending upon the thickness of the furnace wall as long as they areA of. the correct relative lengths, and element 8 does not project into cup 4.

Distributor member 21 is preferably made of a heat resistant alloy, and, as shown in Figs. 2 and 3, is cylindrical in shape. This member is provided on its periphery with a plurality of helically extending ribs 22. Helically extending passages 23 through which the `air flows are formed between the ribs 22 and the inner surface of portion 9 of element 8.

The gas passage through the interior of member 21 is provided with a portion 24 of reduced diameter which forms somewhat of a restriction between element 19 and a plurality of radially extending discharge apertures 25. These apertures extend at an angle of approximately 30 or less from a plane perpendicular to the axis of the member and terminate substantially perpendicular to the side of a low projection formed on the end -of member 21. Passage 24 is of an area substantially equal to or slightly larger than the sum of the areas of apertures 25. There are the same number of apertures 25 and passages 23, and in this case ten of each is shown.

It is desired to project the gas discharged from apertures 25 into the streams of air discharged from passages 23. Since vthis air is moving in a helical directionas it leaves the passages, the apertures are displaced angularly from the passages in the direction of air travel. As best shown in Fig. 2, the apertures terminate in the end of member 21 atV a location radially inward of ribs 22. It is noted that the end of member 21 is silghtly below the end of element 8 for a reason that will be described below.

In the operation of the present burner air and gas are supplied in combustible proportions to a group of burners in afurnace zone from aconventional ratio controller.

cup. Gas travels through element 19 and is discharged through apertures 25 into the streams of air. Mixing of the air and gas begins at this point and continues as they move toward and into the cup.

Smalleddies of air and gas mixture are created in the corner between the end of member 21 and the end of element 8. Additional eddies are created in the curvature of the cup between the side wall and base thereof. The mixture burning in these eddies has a piloting effect on the main flame and helps to keep the combustion stable. Ordinarily, when the burner is in operation no flame is visible. Combustion takes place rapidly and is completed by the time the mixture has reached the outer edge of the cup. The swirling gases heat the cup to an even degree of incandes'cence, and only hot products of combustion are discharged therefrom.

Another form that the distributor member can take is shown in Fig. 4. In this embodiment, distributor member 31 is supported by gas pipe 19 adjacent to the end of element 8 as was that previously described. In differs from the previous one, however, in the manner in which the gas passages are formed. As shown, member 31 is cylindrical in shape and is provided with a restricted portion 32 between its ends. The outer end is threaded to receive a tip 33, preferably ceramic, that is provided on its surface with a plurality of axially extending slits or channels 34 through which the gas ows. Air is supplied, as in the embodiment of Figs. 2 and 3, through a plurality of helical passages 34 formed by helical ribs on the surface of member 31. Eight of the helical passages are shown in this embodiment. It will be noted that the outer ends of slits 34 bend in a radical direction so that gas flowing through them is directed across the whirling streams of air discharged from passage 35. The end of tip 33 overlies the ends of slits 34 both to give direction to the gas and to protect the exits. This end, however, does not extend beyond the end of tubular element 8.

In the form of the invention of Fig. 4 there are more apertures 34 than there are helical passages 3S. For example, tip 33 can be formed with twenty-eight of the slits 34 around its periphery. With this construction, more streams of gas, each having less volume than those ofFig. l, are discharged into the streams of air. Thus in some cases,.particularly with lower gas pressures, earlier complete mixing of the gas and air is obtained. The burner of Fig. 4 operates in the same manner as does that of Figs. 1 to 3.

Burners of the type described herein are intended for use in industrial applications where a large heat release 'is required. A burner of the type described having a distributor diameter of approximately three inches and a cup diameter of twelve inches can release one million B. t. u. per hour of 700 B. t. u. per cubic foot gas. With this type of operation the gas and air pressures are approximately 40 inches water column. As the burner is turned down the gas and air pressures are reduced, and

' the burner has a fairly large turn down ratio. The pressures will, of course, vary with the capacity at which the burner is being fired and the type of gas being used.

Ordinarily the cooling effect of the gas and air flowing past the distributor member will cool it sulliciently so that no harm will be done to it. This cooling is very effective since the distributor does not project into the cup to receive radiation therefrom. If for some reason, however,

the end of the distributor was damaged suciently to break out the aperture forming portion thereof beyond vrestriction 24 or 32, the restriction will serve to prevent an uncontrolled flow of gas into the cup. Thus damage to one burner of a group being supplied by the same ratio controller will not upset the control of the others appreciably by drawing more than its share of gas. Even when the tip breaks, the radially outward ow of air into the cup will draw the gas with it so that burning along the cup will continue. Therefore, torching of the burner and consequent burning of work close in front thereof will not occur.

While in accordance with the provisions of the statutes, l have illustrated and described the best form of embodiment of my invention now known to me it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. A burner including a tubular element adapted to extend through an opening in a furnace wall, a member received in said element and having an end thereof adjacent tothe end of said element, said member being provided on the surface thereof with a plurality of helical grooves that form with said element a plurality of air passages, means to supply air to said passages, said member having a projection on the eend thereof and concentric therewith, means forming a plurality of apertures extending from the interior of said member and terminating in a substantially radial direction at the periphery of said projection to forma plurality of fuel passages, means in said member forming a restriction upstream of said apertures having an area substantially equal to the sum of the areas of said apertures, whereby upon loss or destruction of said apertures the relative sizes of the. air and gas passages will not be substantially changed and means to supply gas through said restriction to said apertures.

2. In an industrial burner, the combination of a pair of concentric cylindrical elements, means to hold said elements in concentric relation with an end of the inner element withdrawn in an end of the outer element, a cup-shaped distributor member placed over said end of the inner element and extending to a point adjacent to the end of said outer element, said member being provided on its surface with a plurality of helically extending ribs that cooperate with the outer element to form a plurality of helically extending air passages between said member and outer element, means forming a plurality of apertures extending radially and at an angle to the axis of said member from points on its surface adjacent to the outer ends of said ribs to the interior thereof to form a plurality of fuel passages, means forming a restriction in said member between the inner ends of said apertures and the interior of said inner element, said restriction having an area substantially equal to the sum of the areas of said apertures whereby upon loss or destruction of said apertures the relative sizes of the air and gas passages will not be substantially changed, means to supply air to the space between said elements, and means to supply fuel to the interior of said inner element.

3. The combination of claim 2 in which the means forming said apertures comprises a removable plug in the end of said member, said plug having ribs on its surface that cooperate with said member to form said apertures, said ribs extending in part axially and in part radially.

References Cited in the le of this patent UNITED STATES PATENTS 659,843 Bray Oct. 16, 1900 1,352,351 Byers Sept. 7, 1920 1,656,907 Bansen Jan. 24, 1928 2,215,079 Hess Sept. 17, 1940 2,561,793 Furczyk July 24, 1951

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