STRUCTURE OF MULTIPLE FUEL BURNER OF TWO PIECES OF THE INTERNAL CHOIR TYPE. DESCRIPTION OF THE INVENTION The present invention generally relates to a burner apparatus for heating devices with fuel fire, in a preferred embodiment thereof, more particularly it relates to a multiple fuel burner structure of the internal jet type formed of two metallic sheets interfiled by two-sided printing. Fuel-induced draft heaters, such as heaters or gas-fired air heating furnaces, are conventionally provided with heat exchange structures having multiple sections with entries arranged in rows. The row of the heat exchanger section is served by a corresponding spaced apart series of fuel burners of the internal jet or inlet type arranged in a row opposite and parallel to the row inlets of the heat exchangers section. During the operation of the furnace, the gaseous fuel is drawn to the burners from an external source of fuel, ignited, and then carried to and through the heat exchanger at its individual entrances. At the same time a blower portion of the furnace forces a flow of air that is recirculated to and from a conditioned space served by the furnace, externally to the heat exchanger to thereby remove the combustion heat and heat the recirculating air. Because there may be a relatively large number of burners of the internal jet type incorporated in the fuel furnace of this general type, various techniques have been proposed to simplify and reduce the cost of the burner part of the furnace or heater. For example, as illustrated in U.S. Patent 5, 035,609 to Riehl, it has been proposed to make each individual burner of the inner jet type from two opposing sheet patterns, and then to attach the individual burners to adjacent corner portions of flame carrier sections. similar to wings incorporated in each outlet portion of the burner. These flame carrying sections to the next stage are incorporated in each burner outlet portion. These sections extend between each outlet of the burner body and serve to provide a flame path from the ignited burner to an adjacent burner. Each burner body has a generally circular cross-section along its length, with a section of intermediate Venturi tube facing downward. In order to inhibit the lifting of the flame, that is to say the separation of the flame from the burner 1 which is undesirable, two flame retaining members are fixed in an opposite relation in opposite outer sections of each end portion of the burner outlet. based on a separate outlet that is inserted to obtain this flame retention function Another proposed multi-burner design is shown in US Pat. No. 5,176,412 where a plurality of tubular venturi section burners are established, which they are integrally formed by two metal foils opposed by stamping so that the individual burner bodies automatically stop at the required row of parallel burners Several well-known problems are presented with these and other types of conventional burner sets of the jet type For example, many conventional structures require complex forms of stamping and They are difficult to assemble and consume a lot of time when doing so with the row aligned precisely with the axes of the parallel main flame. Additionally, the provision of adequate flame retention to prevent axial separation of the individual burner outputs requires multiple components such as side shields and structures inserted into the burner body outlet. further each separate burner of the said type is fed with gaseous fuel from an orifice nozzle connected to a multiple head gas tube and received in an extreme feed nozzle received in the burner body portion. Several conventional designs for this receiving portion have not been shown to be entirely satisfactory due to mechanical instabilities of conventional designs. In addition to these structural problems presented by conventional burners of the mentioned type, also frequently present operating problems. For example several burners produce flame forms and carriers to the next undesirable stage during their operation. As the main burner flame this shape deficiency manifests itself in a too wide flame which tends to laterally overlap its associated heat exchange section in its inlet opening, potentially damaging the heat exchanger inlet section, over time. Therefore, it is necessary and desirable to provide an internal multiple jet burner structure, which eliminates, or at least minimizes, the previous problems as well as their limitations and disadvantages. Therefore, it is an object of the present invention to provide such a multiple fuel burner structure of the internal or incoming jet type. In order to carry out the principles of the present invention, according to a preferred embodiment, a fuel multiple burner structure of the two-part inlet jet type of a first and a second metal leaf member configured equally joined together is formed. a confrontational relationship side by side. According to several aspects of the invention, the structure of the burner has several unique aspects that result in unique structural and functional characteristics. For example to simplify the stamping process used to fabricate the burner structure the deformed first and second sheet members are configured to define spaced apart a plurality of rectangular fuel burner bodies in the cross section that extend along parallel axes and have open end entrance portions rearwardly positioned on a rear side edge of the structure, and an open front exit positioned on the front side edge of the structure. Each body is preferably defined by two deformed triangular sections of the sheet members. During formation of the burner structure, air streams and gaseous fuel are flowed forward through the interiors of the burner bodies, and ignited to create flames and the resulting hot combustion gases are discharged forward from the outlet ends of the burner bodies. Laterally spaced apart surfaces of transverse flame retaining tabs are formed at the outlet end of the burner bodies, and are aligned with the front side edge of the burner structure, and function to prevent a rising of the flame from the outlet ends by intercepting and blocking induced flows of secondary combustion air flowing externally forward along the burner bodies. Extending transversely between the end portions of each pair of adjacent burner bodies and communicating by their interiors, there is a cross-over chamber which is defined by the facing spaced apart portions of the first and second sheet members and has a notch of discharge edge aligned with the front side edge of the burner structure. During operation of the burner structure, a portion of the fuel / air mixture traverses internally each burner body flowing in its associated crossover chamber and outwardly through the notch of the discharge edge of that associated chamber to ignite the burners remaining from the first that has ignited. According to another characteristic of the invention, there are mixing depressions in the exit portions of the burner bodies in each of the walls defining the opposite triangular deformed sections. These depressions help to mix the air and gaseous fuel streams that traverse the burner bodies internally, with each depression preferably having an axially elongated body portion with front and rear ends. Extending transversely from a front end of each depression portion, towards the vertex edge of its associated triangular burner body section, there is a section that inhibits backward flare, and thus prevents it from the flame of the main burner body, which would be undesirable. Somewhat behind the inhibiting section of the flare back there is a transverse deflector of the fuel / air mixture that extends towards the base of the triangular section of the burner and serves to facilitate the deflection of a portion of the fuel / air mixture that passes through a burner body to an associated crossover chamber. According to another characteristic of the invention, the pressure balancing structures are incorporated in the cross-over chambers and function to equalize the discharge pressure of the fuel / air mixture along the lengths of the chamber discharge recesses of crossing or passing. The pressure balance structure are formed by pluralities spaced from depressions formed in the opposite wall portions of the passage chambers and arranged in rows parallel to their discharge edge cut-outs. The depressions or marks in each row are configured and arranged in such a manner that in each discharge edge cutout there is a resistance to the outward outflow of the fuel / air mixture which is maximum in a longitudinally central portion of the notch and progressively decrease, along the remaining lengths of the discharge notch towards the opposite end portions. The overall equalization of the fuel / air pressure along each cross-section discharge edge recess is preferably facilitated by a special configuration of the chambers extending between the end portions of each adjacent pair of cross-section bodies. fuel burner Specifically, each crossing chamber has a rear side edge that is spaced apart from and parallel to the discharge edge cut-out of the passage or cross-section chamber, and is preferably aligned with the rear ends of the wall mixing depressions. Lateral body burner. An arc depression is formed along a major central portion of this rear side edge of the chamber, with the convex side of the arc depression opposite the discharge notch on the front side of the cross or step chamber. According to a further characteristic of the present invention, each rear inlet end portion of the burner body is laterally deformed, with respect to the balance of its burner body of associated rectangular cross section, to create a circularly configured fuel supply orifice that receives and supports a portion of the burner body disposed rearwardly of an open rear air inlet portion that pertains to the burner body balance. This characteristic of the burner body structure facilitates the stable reception and support of the supply orifice nozzles in the rear end portions of the plurality of burner bodies separated from the inlet jet type. DESCRIPTION OF THE DRAWINGS Figure 1 is a partially exploded perspective view of a multiple fuel burner structure of the jet inlet type embodying the principles of the present invention, and of a gaseous multiple fuel head pipe with orifice operatively associated with the structure; Figure 2 is a top plan view on an enlarged scale of the burner structure; Figure 3 is an enlarged partial side elevation view of the burner structure taken along line 3-3 of Figure 1; Y
Figure 4 is a partial cross-sectional view in enlarged scale through the burner structure taken along the line 4-4 of Figure 1. Referring to Figures 1-4, the present invention provides a structure 10 of two-piece stamped metal sheet burner having three parallel, laterally separate portions of a jet fuel burner 10a with rectangular cross-sections (illustratively square) along their lengths. As will be appreciated immediately by the technicians, a greater or lesser number of individual burners 10a may be incorporated into the structure as needed or desired. According to a key advantage of the invention, the structure of multi-chambers 10 as a whole is conveniently and economically constructed from two metal sections of upper and lower sheet formed by embossing 12a, 12b which are cut from an elongate sheet and then interfused, by fixing mechanical deformations 14, in the illustrated relation of frontal opposition. The individual fuel burner portions 10a are combinatorially defined by raised triangular sections in the cross section 16 formed on each of the sections of the sheet 12, a, 12b, and arranged in opposite pairs to form the cross-sectional body sections hollow rectangular, illustrated, of the individual portions of burner 10a. Each section of triangular body 16 has along its length, a vertex edge 16a, and a base edge pair 16b. As illustrated, the elongated burner bodies 10a, are arranged in a laterally spaced, but longitudinally parallel relationship along the entire structure 10 of the burner and extend along between the front and rear side edges 18, 20 of the structure. The aligned end edges of the upper and lower metal foil sections 12a, 12b also define corresponding left and right edges 22, 24 of the burner structure 10. A representative structure of three burners 10 is shown in FIGS. 1 and 2, by thus there are two "end" burners 10 a placed adjacently to the right and left at the lateral end edges 22 and 24, and a "central" burner 10a disposed between the end burners. Opposite portions of the upper and lower sheet metal or foil sections, facing one another, are raised to form intermediate passage or junction fuel chambers 26 that extend between each pair of adjacent burner body portions at the end portions of output from the burner body portions (this is the 'rightmost' portions of the burner body portions as seen in Fig. 1, and the bottom end portions of the burner body portions as seen in FIG. Fig. 2). The crossing chambers or passage 26 generally have rectangular configurations, elongated in a direction transverse to the lengths of the burner body portions 10a, and have indentations 28 formed between opposite edge portions 29 and essentially straight. These fuel passage or junction chambers 26 communicate along opposite end portions thereof with the interiors of their associated burner body portions 10a and have open lateral edge cutouts 30 through the flame outlet disposed between each adjacent pair. of portions 10a of burner body. The opposite ends of the upper and lower facing sections of the metal foil 12a, 12b are raised to intermediately form fuel passage chambers 26 that extend between each pair of adjacent burner body portions at the outlet of the end portions of the burner (that is, right end portions of the burner body seen in FIG 1 and lower end portions thereof seen in FIG 2). The fuel chambers 26 generally have rectangular configurations, elongated in the direction transverse to the lengths of the portions of the burner body 10a, and have arcuate indentations 28 formed essentially straight, with opposite edge portions by the inner edge 29. These passage chambers 26 communicate along opposite end portions. thereof with the interiors of its associated portions of burner body 10a and have open flame exit side edge recesses 30 disposed between each adjacent pair of burner body portions 10a. At opposite ends of the structure 10 the portions 26a of the fuel passage chambers 26 are flattened, to bring the facing portions of their opposite walls 12a, 12b together, in a manner that leaves a laterally truncated portion 32 of the pre-chamber 26, intact, each of the two truncated portions 32 shown has an end slope portion 334 spaced inward from the adjacent front side 18 and disposed opposite to the side edge portion of the associated internal passage chamber. . The interior height of each of the two illustrated fuel flow chambers 26 is essentially constant over its entire area, including the portion extending along its associated outlet cutout 30. The portion of the walls 12a , 12b on opposite sides of each chamber 26 are kept apart from one another by means of three dimples or recesses projecting inward, interior, intermediate and exterior 36, 38, 40 (see figures 2 and 3) formed in each of the walls 12a, 12b and arranged in a row of six recesses placed inwardly and extending parallel to the two flame exit edge recesses 30. With a purpose to be discussed later, those recesses 36, 38, 40 are specially configured and placed to improve the operation of the burner structure 10. The recesses or dimples 36, 38, 40 are oval in shape and as best illustrated in Figure 3, on each wall 12a, 12b, the widths of the recesses 36 , 38 are gene erally equal and wider (in a direction transverse to the lengths of the burner body 10a) than the width of the dimple 40. The dimples 36 and 38 in each wall 12a, 12b touch the opposite wall, but the recesses 40 do not, and they form small lights or distances 42 with the opposite wall 12a or 12b as may be the case. Additionally, there are small horizontal spaces between the three recesses 36, 38, 40 in each wall 12a, 12b as well as a small horizontal distance between the two adjacent recesses 36. With reference to figures 1-3, at the exit end of each burner body portion 10a there are four outwardly projecting tongues of flame retention 44, one in each of the four walls of the burner body of rectangular section aligned with the front side edge 18 of the burner structure 10 and remaining in planes perpendicular to the parallel portions of the sheet sections 12a, 12b between the burner bodies 10a. As illustrated, each tab 44 has an external vertical side edge 46 that is transverse to the metal sections 12a, 12b between the burner bodies 10a. Immediately behind each of the tongues 44 is a depression 48 formed in an end exit portion of the wall of the triangular body section 16 where the tongue 44 is formed. Each depression 48 has an elongated body portion 50 longitudinally parallel to the length of the burner portion 10a, an inner end 52 generally aligned with the edge portions of the inner side 29 of the fuel chambers 26, a front transverse portion 54 extending from the body portion 50 towards the edge of the body. vertex 16a of the triangular section 16, and a transverse intermediate portion 56 extending toward a base edge 16b of the triangular section of the body 16. Considering now Figures 1, 2, and 4, the initially rectangular or rear entrance ends of the individual burner portions 10a are deformed to define end upper and lower lobe portions of entry to each burner 58, projecting outwardly from a circular mounting portion, central 60, and four primary combustion air inlet openings 62 at the rear ends of the still rectangular portion of the burner body 10a. These extreme inlet openings are supplemented by the side inlet openings 64 formed in the walls of the triangular body sections 16 adjacent their inlet ends. To facilitate accurate alignment of the facing sections stamped from foil or sheet metal 12a, 12b before being interlocked by the mechanical attachment strains 14, the circular alignment holes 66, through which alignment members can be temporarily inserted. , they are formed in sections 12a, 12b. Additionally formed in the sheet sections 12a, 12b are mounting holes 68 of the burner structure adjacent internally to the fuel passage chambers 26, and path control and wireway holes 70 adjacent inward with the rear side edge 20. of the burner structure 10 Several of the unique characteristics of the multiple fuel burner structure 10 of the inlet jet type described above, cooperate with each other to provide the burner structure 10 with a variety of advantages compared to conventional burner devices. burner with jet inlet. For example, the burner structure 10 is fairly easily installed opposite a series of combustion tube inlet distances (not shown) of a furnace or fire heater with induced current fuel, by simply attaching the structure 10 to a member of suitable support, using fasteners that extend downward through the mounting holes 68, and then fixing the support member to the heater. Routine holes 70 provide paths to pass several wires necessary for installation. With the burner structure 10 in place, a spaced array of hexagonal shaped fuel port nozzles 72 (see Figure 1) operatively mounted on a manifold gas supply manifold tube 74 are inserted into the circular center inlet portions. 60 at the rear ends of the burner body portions 10a as illustrated in the phantom lines in Figure 4. Because of their configurations, these circular inlet portions 60 provide a remarkably increased degree of nozzle support stability in comparison, for example a pair of tabs bent towards each other on opposite sides of each nozzle, as used in some of the prior art embodiments for the burners. Referring again to Figure 1, during operation of the burner structure 10, the fuel 76 from the nozzles 72 is injected into the rear inlet ends of the burner body portions 10a and is drawn forward through the inside the burner bodies and is mixed there with primary combustion air 78, simultaneously pulling into the interior of the burner body portion through the extreme and side air inlets 62 and 64. The fuel / air mixture leaving the end of discharge of one of the portions 10a is adequately ignited to form a main burner flame 80 and produces hot combustion gases which are injected into the inlet opening of the combustion tube in line with the outlet end of the burner body that touches it. The flame created by the ignition of the fuel / air mixture in the first burner body portion 10a is expanded by the passage chambers 26 to create the other main burner flames 80 and the recess flames 82 of the chamber outlet schematically illustrated, between each pair of burner body portions 10a. The aforementioned flattening of the portions of the passage chambers 26 in opposite corner portions of the burner structure 10, advantageously prevent the propagation of passing flames away from the opposite ends of the structure 10 in the direction transverse to the axes of the main flames 80. The single rectangular cross-section of the burning portions 10a, as opposed to the configurations of the prior art of circular shape, with mixed sections of reduced diameter Venturi type, greatly simplifies the stamping portion of the manufacture of the structure 10. Instead of the Venturi section of cross section to the central length, the extreme discharge depressions 48 formed in four walls of each portion 10a serve to improve the mixing of the fuel and air, which are carried forward by the interior of the portions 10a of the body of the burner. At the discharge ends of the portions 10a, the tabs 44 act as blocking shields to prevent induced air flows of secondary air, moving forward in a longitudinal direction along the outside of the portions 10a, which adversely affect the main flames 80 causing them to rise and separate from the discharge ends of the portions 10a. The tongues 44 thus effectively act as flame retaining members positioned transversely to the axes of the main burning flames 80, and placed in alignment with the front side edge of the burner structure 10. With reference to Figures 2 and 3, the lateral depressions 48 formed in the discharge ends of the portions 10a, not only serve to improve the mixing of the gaseous fuel and the air that traverses the burner bodies internally, but also performs two other useful functions during the operation of the burner structure 10. Specifically, the front transverse portions 54 of the depressions 48 serve as restrictions to inhibit backward fl ow in the interiors of the burner bodies, and the intermediate transverse portions of the depressions 48 function to deflect a portion of the gas mixture / air flowing through the bodies 10a laterally to the passage chambers 26 pa to start the ignition of the burners from an ignition initially. Once the fuel / air mixture enters the passage chambers 26 between the adjacent pairs of the portions 10a of the burner bodies, its pressure profile horizontally through each open outlet edge cutout 30 of the flame is equalized by the specially designed configurations of and in cooperation between the chambers 26 and the opposite sets of recesses or dimples 36, 38, 40. Specifically, the arc indentations 28 in the passage chambers 26, in combination with the inner edge portions 29 of the chambers 26, generally aligned with the inner ends 52 of the side indentations 48 of the burner body tend to distribute more evenly the outflow of the fuel / air mixture through the exit edge cut-outs 30 than in the case of the conventional passage cameras. The desirable horizontal equalization of the fuel / air mixture in its discharge flow along the lengths of the outlet recesses 30 is further improved by the trajectory and the relative size of the recess sets 36, 38, 40. better appreciated in Figure 3, the opposing sets of dimples 36, 38, 40 arranged in each passage chamber 26, provide in each exit notch 30 a resistance to the outflow of the fuel / air mixture from the notch that is maximum in the horizontal center of the recess and decreases progressively towards the opposite horizontal ends of the recess. Additionally, small spaces or lights 42 between the smaller recesses or dimples 40 and their opposing metal sheet plate walls facilitate lateral propagation of the passage flames 82 from one burner body to another burner body. As you can see from the above, the present invention provides a burner structure fed with multiple fuel of the input jet type 10, which has a simple design, is relatively easy and inexpensive in its manufacture, has only two parts, provides automatic parallel alignment of its sections of burner bodies, and provides improved performance compared to multiple inlet jet burner assemblies of conventional designs.