US3521988A - Piloted main flame burner with burner ribbons - Google Patents

Description

J. H. FLYN N- 3,521,988

PILQTED MAIN FLAME BURNER WITH BURNER RIBBONS July 28, 1970 Filed March 14, 1968 United States Patent US. Cl. 431-284 1 Claim ABSTRACT OF THE DISCLOSURE A longitudinal burner casing has a peripheral wall of which adjacent Wall parts diverge substantially rectangularly from a longitudinal corner of the casing, and a longitudinal partition in the casing dividing it into main and pilot gas compartments. Machined into the casing corner is a longitudinal, diagonally inwardly directed, groove extending through the pilot compartment and having in the partition a bottom with a median longitudinal through-slot to the main compartment. Inserted in the groove and seated on the remaining bottom thereof are two spaced U-channels with pilot flame ribbons therein and main flame ribbons clamped between the channels, with these channels dividing the pilot compartment into sections with which they are in communication through spaced holes in the respective channels.

This invention relates to ribbon burners in general, and to ribbon burners for producing high velocity main flame and piloting flames therefor in particular.

A prior burner of the type with which the present in vention is concerned has in its casing a longitudinal slot at the top which is open to the gas compartment therein and receives a main and pilot flame port assembly in the form of spaced U-channels holding pilot burner ribbons, and main burner ribbons which are clamped between the channels. With the slot being usually arranged to lie with its median plane in the longitudinal plane of symmetry of the casing, and with the slot parting the casing thereat over its entire length, the effect of peripheral expansion of the casing throughout on heat-up of the burner in operation is particularly severe at the slot and demonstrates itself by highly objectionable gaping of the walls of the slot from the flame port assembly therein with ensuing gas leakage paths therethrough and uneven pilot as well as main flames over the length of the burner. Further, with the slot lying in the longitudinal plane of symmetry of the casing and being, moreover, of considerable depth to accommodate the U-channels which are usually of considerable height, especially in a burner casing in which they are to extend through a pilot gas compartment into a therefrom partitioned main gas compartment to seal the latter from the former, the casing is sufliciently weakened structurally over the depthwise extent of the slot there to bellmouth all too readily on forced insertion of the flame port assembly, also with ensuing gas leakage paths and uneven pilot and main flames over the length of the burner.

It is among the objects of the present invention to provide a burner of this type in which gas leakage paths 'through the slot in the burner casing and the flame port assembly therein and ensuing uneven pilot and main flames due to peripheral thermal expansion of the casing and/or bellmouthing of the slotted casing part, are eliminated.

It is another object of the present invention to provide a burner of this type in which the cross-sectional shape of the casing provides a corner which is formed by the junction of peripheral wall parts of the casing that con- 3,521,988 Patented July 28, 1970 verge substantially rectangularly to each other, and the slot for the reception of the flame port assembly is machined into this corner of the casing throughout its length and in an inward direction diagonal with respect to the converging wall parts. -In thus arranging the casing and slot, peripheral expansion of the casing in operation of the burner occurs at the slot in a direction inclined, preferably at angles of substantially 45, to the slot walls, rather than substantially at right angles to the slot Walls as in the aforementioned prior burner, wherefore ensuing gaping of the opposite walls of the slot from the flame port assembly therein is in any event much less than in this prior burner, and may readily be kept within limits at which for all practical intents and purposes gas leakage paths through the slot and ensuing uneven flames over the burner length are eliminated.

It is a further object of the present invention to provide a burner of this type in which the gas chamber in the casing is by a longitudinal partition therein divided into main and pilot compartments of which the pilot compartment is next to the casing corner, and the aforementioned diagonal slot for the reception of the flame port assembly is in the form of a groove which extends through the pilot compartment and has its bottom machined in the partition, with this groove bottom having over its length and a mid-portion of its Width 21 through-slot to the main compartment to leave bottom shoulders on the opposite groove walls, and the U-shaped channels of the flame port assembly being forced to rest with their closed bottoms on these bottom shoulders. In thus arranging the casing slot and mounting the flame port assembly therein with the channels resting on the bottom shoulders, the slot is further sealed against gas leakage therethrough,

0 especially from the main compartment, under any and all conditions, including peripheral expansion of the casing in operation of the burner.

Another object of the present invention is to provide a burner of this type in which the aforementioned chamberdividing partition in the casing is at the slot therein also in the form of a corner at the junction of converging partition parts which preferably extend substantially parallel to the peripheral wall parts of the casing that join to form the outer casing corner. With this arrangement, gaping of these partition parts from the flame port assembly therebetween on peripheral expansion of the easing in operation of the burner may also readily be kept within limits at which for all practical intents and purposes gas leakage paths thereat and ensuing uneven flames over the burner length are eliminated.

It is a further object of the present invention to provide a burner of this type in which the aforementioned corner construction of the casing outside and inside thereof is re-enforced to the point where this corner structure will, despite its parting by the slot therein, respond to peripheral expansion of the casing in burner operation unnoticeably in gaping from the inserted flame port assembly, and will respond to the tightest insertion of the flame port assembly equally unnoticeably in bellmouthing. This is achieved in particularly simple manner by providing the preferably cast casing with sets of integral ribs, of which the ribs of two sets extend in the pilot gas compartment and connect the peripheral wall parts with the nearby partitionparts of the aforementioned corner structure of the casing on the opposite sides of the slot therein, and the ribs of a third set extend in the main gas compartment across the inner corner and tie together the partition parts converging on this corner. With this arrangement, these partition parts are by the ribs in the main gas compartment held directly and most effectively against gaping from the inserted flame port assembly on peripheral casing expansion in burner operation, and the peripheral wall parts are by the ribs in the pilot gas compartment directly connected with the partition parts, with the overall result that the corner structure of the casing is, despite the slot therein, extremely rigid and will not effectively yield to stresses ensuing from peripheral casing expansion or insertion of the flame port assembly into the slot in even particularly tight manner.

Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

FIG. 1 is a front view of a burner embodying the present invention;

FIG. 2 is a side view of the burner;

FIG. 3 is a section through the burner taken substantially on the line 33 of FIG. 1;

FIG. 4 is a fragmentary section through the burner taken on the line 44 of FIG. 1;

FIG. 5 is a fragmentary section through the burner taken on the line 55 of FIG. 2; and

FIG. 6 is a fragmentary top view of the burner.

Referring to the drawings, and more particularly to FIGS. 1 to 3 thereof, the reference numeral 10 designates a burner having a longitudinal burner casing 12 With a chamber 14 and an internal partition 16 which divides the chamber into main and pilot gas compartments 18 and 20. The casing 12 is preferably cast, with the peripheral wall 22, end walls 24 and partition 16 thereof being formed integrally with each other. Provided in the casing 12 is a machined slot 26 which extends longitudinally over the length of the casing 12 (FIG. 5), and extends depthwise through the peripheral casing wall 22, pilot compartment 20 and partition 16 (FIG. 3), and is adapted for the reception of a flame port assembly 28.

The part of the slot 26 in the peripheral casing wall 22 is in a longitudinal corner structure of the casing which is formed at the junction of two converging peripheral casing wall parts 32 and 34 that extend transversely, and preferably substantially rectangularly, to each other. The slot 26 has a median plane p lying substantially in the casing corner 30 and extending inwardly diagonally with respect to the converging wall parts 32 and 34 (FIG. 3), with this median plane p preferably forming with the wall parts 32, 34 angles A of substantially The flame port assembly 28 comprises in this instance main flame ribbons 36 and pilot flame ribbons 38 of any suitable kinds, as well as two U-channels 40 and 42 with closed bottoms 44 (FIGS. 3 and 6). The pilot flame ribbons 38 are tightly fitted in the open tops of the channels 40 and 42 and provide gas ports for feeding pilot flames thereat, while the main flame ribbons 36 are tightly clamped between the channels 40 and 42 at the top and provide gas ports for feeding main flames thereat, with the channels being, in turn, tightly clamped to the opposite side walls of the slot 26 to thereby seal the pilot compartment 20 from the main compartment 18 and also divide the pilot compartment 20 into sections 48 and 50 which are, moreover, also sealed from each other by these channels 40, 42 which extend in the slot 26 within the thickness confines of both end walls 24 of the casing (FIG. 5). The flame port assembly just described is preferably preassembled into a self-contained unit before its forced insertion into the slot 26, and the channels 40, 42 and burner ribbons 36, 38 are to this end held together by longitudinally spaced crosspins 51. The channels 40 and 42 have longitudinally spaced holes 52 through which to receive combustible gas from the respective pilot compartment sections 50 and 48 for feeding the pilot flames at the pilot ribbons 38, while the main flames at the main ribbons 36 are fed with combustible gas from the main compartment 18 via slot 26 and the space s between the channels 40, 42. The slot 26 beyond the opposite ends of the flame port assembly 28 therein is effectively sealed from the main and pilot compartments 18 and 20 by suitable spacers 53 and 55 which are held in place by end caps 57 on the opposite casing ends (FIGS. 1, 2 and 5).

The casing 16 is also provided with an inlet 56 to the main compartment 18, with this inlet being through a conduit 58 connected with a usual mixer (not shown) in which gas and air is mixed into a combustible gas with which the main compartment 18 is supplied. The casing 12 has in this instance another inlet 60 to the pilot compartment section 48, with this inlet 60 being through a conduit 62 connected with another mixer (not shown) which supplies combustible gas to the compartment section 48. The gas conduit 58 also has an interposed valve (not shown) for quantitative regulation of the combustible gas to the main compartment 18, and the gas conduit 62 may also have an interposed valve. The pilot compartment section 58 is supplied with combustible gas directly from the main compartment 18, and the partition 16 is to this end provided with an aperture 64 (FIG. 4). For regulation of the gas flow into the compartment section 50, there is provided a valve plug 66 which is threadedly received in the casing 12 as at 68 and extends toward the aperture 64. The valve plug 66 is adjustable from the outside of the casing 12 to regulate the flow passage from the main compartment 18 into the aperture 64, and the valve plug is locked in adjusted position by a nut 70. Secured at 72 to a stud 74 in the main compartment 18 is a bafile 76 which is in line with the gas inlet 56 and serves to divert the instreaming combustible gas into a course substantially longitudinally of the main compartment for even distribution in the latter.

Part of the slot 26 from its outer end through and beyond the pilot compartment 20 is, by machining, widthwise enlarged equally on both sides of the median plane p to form a groove 78 with opposite side walls 80 and 82 and bottom shoulders 84 and 86 which are formed in the partition 16 on opposite sides of the slot 26 therein. The purpose of the partial groove formation of the slot 26 is the provision of the bottom shoulders 84 and 86 which advantageously serve as rest shoulders for the closed bottoms 44 of the channels 40 and 42, with these channels being clamped sidewise tothe respective groove walls 80 and 82.

In operation of the burner, the casing 12 becomes heated from the issuing flames, and this will bring about peripheral expansion of the casing. Such thermal peripheral casing expansion is of concern at the casing slot 26 and the flame port assembly 28 therein, because of ensuing gaping, more or less, of the slot walls, and in this instance of the groove walls 80 and 82, from the adjacent channels 40, 42 of the flame port assembly which may give rise to gas leakage thereat that may effect the evenness of the flames over the burner length. However, due to the casing corner structure 30 and the provision therein of the diagonally directed slot 26, thermal peripheral casing expansion brings about virtually negligible gaping of the opposite walls of the slot from the flame port assembly therein. This, thermal peripheral expansion of the casing at the slot 26 is primarily in the direction of the arrows 9t), i.e., at angles of substantially 45 to the median plane 2 of the slot, wherefore actual gaping of the slot walls from the flame port assembly is but a fraction of the actual expansion displacement of these slot walls. Further, regardless of gaping of the slot walls from the flame port assembly, gas leakage from the main compartment through the slot is effectively prevented by virtue of the rest of the channels 40, 42 with their bottoms 44 on the bottom shoulders 84, 86 in the slot.

To keep gaping of the slot walls from the flame port assembly in thermal peripheral casing expansion at a minimum which to all practical intents and purposes is negligible and does not affect the evenness of the flames throughout the burner length, the partition 16 is at the slot 26 therein also formed as an inner corner structure 92 of the casing. To this end, the corner 92 is formed by the junction of two converging partition parts 94 and 96 which are inwardly spaced from, and extend substantially parallel to, the peripheral wall parts 32 and 34, respectively, of the casing, with the median plane p of the slot 26 lying substantially in both casing corners 30 and 92 (FIG. 3).

In order to keep gaping of the slot walls from the flame port assembly on thermal peripheral casing expansion at an absolute minimum at which flames from many burners operating at maximum capacity have been observed to be and remain entirely even throughout the burner length, and also to prevent any possible bellmouthing of the slotted casing part on driving the flame port assembly into the slot even with a particularly tight fit, the casing 12 is also provided with series of longitudinally spaced, integral ribs 98, 100 and 102 (FIGS. 3 and 5). The ribs 98 extend transversely of the casing 12 and connect the peripheral wall part 34 with the partition part 96 next to the slot 26, whereby these parts 34 and 96 are strongly tied together into a highly rigid structure. Similarly, the ribs 100 extend transversely of the casing and connect the peripheral wall part 32 with the partition part 94 next to the slot 26, whereby these parts 32 and 94 are also tied together into a highly rigid structure. Finally, the ribs 102, which also extend transversely of the casing, connect the partition parts 94 and 96 across and next to the inner casing, corner 92. With these rib formations 98 to 102, the casing structure at and in the vicinity of the slot 26 is re-enforced and its rigidity increased so highly that bellmouthing of the casing thereat is avoided even at the tightest fit of the flame port assembly in the slot, and whatever slight gaping of the slot walls from the flame port assembly may occur on thermal peripheral casing expansion in burner operation at maximum capacity for any length of time, this will assuredly have no eflect whatsoever on the evenness of the flames throughout the burner length.

The invention may be carried out in other specific Ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein,

What is claimed is:

1. A burner, comprising a longitudinal casing having a chamber, a peripheral Wall and a longitudinal partition dividing the chamber into main and pilot gas compartments, with parts of said wall defining part of said pilot compartment and converging on each other substantially rectangularly to each other to form at their junction an outer longitudinal corner on the casing, and parts of said partition being spaced from, and extending substantially parallel to, said converging, wall parts and converging on each other to form at their junction an inner longitudinal corner on the casing, and said casing having in said converging wall parts and partition parts a longitudinal groove with opposite parallel side walls and a bottom wall, of which the side walls extend into, and said bottom wall is in, said converging partition parts, with said groove having a median plane lying substantially in said outer and inner casing corners, and said bottom wall having midway of its width a slot extending through said converging partition parts and being of smaller width than said groove to leave at said bottom wall spaced opposite bottom shoulders, and sets of integral ribs, of which the ribs of all sets are longitudinally spaced and extend transversely of the casing, with the ribs of two sets extending from said converging wall parts to said converging partition parts on opposite sides, respectively, of said groove, and the ribs of another set projecting from said partition parts into said main compartment and extending across said slot, and a flame port assembly fitted in said groove including two U-channels spaced from each other and abutting said side walls and bottom shoulders of said groove to seal said pilot compartment from said main compartment and divide said pilot compartment into two sections sealed from.

each other.

References Cited UNITED STATES PATENTS 2,428,274 9/ 1947 Flynn et al. 43l278 2,748,848 6/1956 Flynn 431-284 EDWARD G. FAVORS, Primary Examiner US. Cl. X.R. 239553.

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