JPH07293830A - Thick and thin fuel combustion device - Google Patents

Abstract

PURPOSE:To reduce the amount of CO generated in thick and thin combustion device by a method wherein rod-type obstacle members, guiding combustion gas from the lower side position of one flame port to the lower side position of the other flame port, are provided in a specified direction in parallel at positions at lower side than primary flame and in secondary flame. CONSTITUTION:A plurality of flame port forming members (a), provided with narrow-width flame ports 1, 2 in a second direction M orthogonal to a first direction, are provided in parallel to the second direction M. Rod-type obstacle members 100, guiding combustion gas from the lower side position of one of the flame ports to the lower side position of the other flame port, are provided in parallel to the second direction M at positions at the lower side of either one of a plurality of flame ports 1 or flame ports 2 and the lower side of primary flame F1 formed in the flame port 1 but in secondary flame F2 formed at the lower side of both flame ports 1, 2. According to this method, high-load combustion can be realized under a condition that the generation of CO is reduced while combustion under a condition that the generated amount of NOx is restricted is permitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to reduction of CO in exhaust gas of a combustor used for a water heater, a boiler and the like, and more specifically, to a bottomed rectangular tubular casing. , A plurality of flame hole forming members that are long in the first direction along the end face and that form narrow flame holes in the second direction orthogonal to the first direction are arranged in parallel in the second direction. The formed burnt holes are alternately formed in the second direction as a burnt hole for a rich air-fuel mixture in which a rich air-fuel mixture with excess fuel burns and a burnt hole for a light-fuel mixture in which a lean air-fuel mixture leanly mixed with fuel burns The present invention relates to a concentrated combustion device.

[0002]

2. Description of the Related Art In such a rich-lean combustion device, flat flame holes are arranged in parallel in a second direction, and the arranged flame holes are alternately arranged for rich-mixture flame holes and light-mixture flame holes. By configuring as above, combustion assist is performed between the flames formed in the mutual flame holes, and stable combustion is performed in combustion with a high combustion load.

[0003]

Now, with the above-mentioned rich-lean combustion device, it is possible to perform high-load combustion,
Since the lean fuel is burned on the lower side of the light-air mixture flame hole, incomplete combustion is likely to occur, and the generation of carbon monoxide CO becomes a problem.

Therefore, an object of the present invention is to obtain a rich / lean combustion device capable of reducing the amount of CO generated in the rich / lean combustion device.

[0005]

To achieve this object, a characteristic configuration of a rich / lean combustion device according to the present invention is that one of a plurality of rich mixture gas flame holes or a plurality of light mixture gas flame holes is provided. Side, the primary flame F formed in the rich mixture air hole
A rod-shaped obstacle member for guiding combustion gas from one flame hole lower side position to the other flame hole lower side position at a position in the secondary flame F2 formed on the lower side than 1 and on the lower side of both flame holes, They are arranged side by side in two directions. In this configuration, it is preferable that the rod-shaped obstacle members are rod-shaped members each having a width approximately equal to the flame hole width in the second direction of the corresponding flame hole and longer than the flame hole length in the corresponding first direction. . Further, in the above configuration, the primary air ratio of the rich air-fuel mixture with excess fuel is 0.
It is preferably 4 to 0.8, and the primary air ratio of the lean air-fuel mixture in which the fuel is diluted is preferably 2.0 or more. Further, in the above structure, it is preferable that the rod-shaped obstacle member is any one of a rod, a pipe and a water pipe made of a heat resistant material.
Further, in the above-mentioned configuration, when the rod-shaped obstacle member is arranged on the lower side of the plurality of rich-mixture flame holes, the width of the rich-mixture flame holes in the second direction is A, When the separation distance in the flame forming direction from the flame hole is B, it is preferable that A and B have a relationship of 2 × A <B <20 × A. Further, in the above configuration, when the rod-shaped obstacle member is disposed on the lower side of the plurality of light-air mixture flame holes, the width of the light-fuel mixture flame hole in the second direction is D, and the rod-shaped obstacle member for light-air mixture is used. When the distance from the flame hole in the flame forming direction is E, it is preferable that D and E have a relationship of 3 × D <E <30 × D. Further, in the above structure, the primary flames F1 formed in the rich mixture flame holes are individually formed in each of the rich mixture flame holes in the second direction, and the secondary flames F2 include a plurality of secondary flames F2. It is preferable that a single flame surface is provided on the lower side of these flame holes for the rich air-fuel mixture and the plurality of light-air mixture flame holes. The actions and effects thereof are as follows.

[0006]

That is, in this rich / lean combustion device, the rod-shaped obstacle member is formed in the secondary flame at the upper side of the rich / lean mixture flame hole in the secondary flame so as to match the forming direction of these flame holes. To place. Since the rod-shaped obstacle members are arranged side by side along the direction in which the rich and lean flames are arranged, the action of this member causes the combustion gas and the lean combustion gas on the rich combustion side in the secondary flame formed by the entire combustion device Effectively promotes mixing with the side combustion gas. That is, for example, when it is arranged on the rich mixture flame hole, the high temperature combustion gas is effectively guided to the lean flame side. The air is guided to the high temperature side of the rich flame to promote combustion. Therefore, the combustion of the air-fuel mixture on the side of the light burner, which is difficult to completely burn, is also promoted, and the generation of CO is reduced in the entire device. Further, if this member is made of a heat radiating member, the decrease of the flame temperature is promoted, and as a result, the emission of NOx is reduced. Furthermore, if these bar-shaped obstacle members are provided with bar widths each having a width approximately equal to the flame hole width in the second direction of the corresponding flame hole and longer than the flame hole length in the corresponding first direction, efficiency is increased. Combustion gas can be mixed well to avoid incomplete combustion. here,
Explaining the arrangement position of the rod-shaped obstacle member, this is
If it is arranged in the primary flame on the rich combustion side, incomplete combustion of this flame will be induced, but in the case of the present application, since it is located above this primary flame, After the primary flame is well formed, it is mixed with the light flame side to obtain a high complete combustion state.

Further, when the primary air ratio of the rich air-fuel mixture with excess fuel is 0.4 to 0.8 and the primary air ratio of the lean air-fuel mixture in which the fuel is diluted is 2.0 or more, Stable high load combustion and low NOx
It is possible to realize the light and shade combustion of. Further, when the rod-shaped obstacle member is any one of a rod, a pipe, and a water pipe made of a heat-resistant material, excellent NOx reduction can be achieved with a long life. When using the water pipe, the cooling state can be adjusted by adjusting the amount of cooling water flowing in the water pipe. Furthermore, in the case where the rod-shaped obstacle member is disposed on the plurality of rich mixture flame holes, the width of the rich mixture flame hole in the second direction is A, and the width of the rod-shaped obstacle member from the rich mixture flame hole is A. A and B are 2 × A <B <20 × A
In the flame of the rich-lean combustor, the highest temperature in the flame of the rich-lean combustor is 2 × A to 20 above the primary flame of the rich-combustor.
The position is × A, and NOx can be effectively reduced. On the other hand, when the rod-shaped obstacle member is arranged on the plurality of light-air mixture flame holes, the relationship between the flame-hole width D and the height E on the light-flame side is 3 ×.
By maintaining the relationship of D <E <30 × D, similarly effective low NOx and complete combustion state can be achieved. Further, the primary flame F1 formed in the rich mixture flame hole is formed individually in each of the rich mixture flame holes in the second direction, and the secondary flame F2 includes a plurality of rich mixture gases. For combustion flames and multiple light-air mixture flames, if they are formed with a single flame surface on the lower side of these flames, uniform combustion in the secondary flame As a result, the stable combustion state can be secured.

[0008]

Therefore, it is possible to obtain a rich-lean combustion device capable of realizing high-load combustion in a state in which CO is less generated, and performing combustion in a state in which the amount of NOx generated is suppressed as compared with the conventional case. did it.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. First, the overall configuration of the rich / lean combustion device will be described with reference to FIGS. 1 to 5. In short, the rich-lean combustion device is long inside the casing (K) with a bottomed rectangular tube and is long in the first direction L along the end face and narrow in the second direction M orthogonal to the first direction L. A plurality of rectangular tubular bodies a serving as flame hole forming members that form the flame holes are arranged in the second direction M, and the arranged flame holes are alternately arranged in the second direction M to cause excess fuel. A rich mixture flame hole 1 for burning a rich mixture gas and a light mixture flame hole 2 for burning a lean mixture mixture of a lean mixture of fuel are provided.

Further details will be described below. Inside the bottomed rectangular tubular casing K, a plurality of flat rectangular tubular bodies a as the flame forming members are housed in a state of being arranged at intervals h.

In the rectangular tubular body a, a rich mixing portion O for producing a rich air-fuel mixture having a small primary air suction ratio is formed, and on the side walls 6 and 7 of the adjacent rectangular tubular body a and casing K. In the enclosed space, the light mixing portion P having a large primary air suction ratio is formed. On the upper surface of the rich mixture portion O, the rich mixture flame hole 1
And the light mixture flame hole 2 is formed on the upper surface of the light mixing portion P.

The bottom plate 5 of the casing K is provided with a rich mixing supply port 5a and a light mixing supply port 5b corresponding to the deep mixing part O and the light mixing part P, respectively. The opening area is formed to be larger than the opening area of the supply port 5a for dense mixing.

Below the bottom plate 5, a supply port 5a for dense mixing is provided.
Fuel gas supply pipe 3 for dense mixing, which has an ejection nozzle 3a as an ejection portion for ejecting fuel gas toward the air, and an ejection nozzle as an ejection portion for ejecting fuel gas toward a light mixing supply port 5b Two mixing fresh fuel gas supply pipes 4 with 4a are provided.

Therefore, the fuel gas is blown into the rich mixing portion O and the light mixing portion P through the supply ports 5a and 5b, and the primary air for combustion is sucked along with the fuel gas. Has been done. In the rich mixing portion O, a rich air-fuel mixture having a small suction ratio of primary air is generated, and in the light mixing portion P, a light air-fuel mixture having a large suction ratio of primary air is generated. .

That is, the rich flame is formed above the flame hole 1 provided in the rich mixing portion O, and the lean flame is formed in the lean mixing portion P.
Is formed above the flame hole 2 provided in, and while maintaining the ignitability and the flame holding effect by the rich flame, by performing a desired amount of combustion with the combustion temperature being lowered by the lean flame, The combustion is configured so that the generation of NO _x (nitrogen oxide) in the exhaust gas is reduced as much as possible.

The rich / lean combustion device in this embodiment is composed of a so-called Bunsen burner.

The casing K for accommodating the rich mixing portion O and the light mixing portion P, and the rich fuel gas supply pipe 3 and the light fuel gas supply pipe 4 are in the shape of a bottomed rectangular tube forming the combustion chamber of the rich and lean combustion device. It is provided inside the barrel R. At the outer peripheral portion of the casing K, a gap 8 is formed by the cylindrical body R and the casing K as a passage area for the secondary combustion air for combustion in the side peripheral portions of the rich mixing portion O and the light mixing portion P. The gap 8 is
The secondary air for combustion is configured to ventilate upward, and the secondary air for combustion is supplied to the flame holes 1 and 2 and, at the same time, the casing K is opened by the flow of the secondary air for combustion. It is configured to have an effect of cooling and blocking heat from the casing K to the barrel R.

At the bottom of the barrel R, the bottom is located at a position offset to one side in the direction in which the rectangular tubular bodies a are arranged in parallel.
A fan discharge port 9 a of a blower fan 9 that blows the primary combustion air and the secondary combustion air toward the bottom plate 5 and the gap 8 is provided.

The fan discharge port 9a is provided with an air rectifying plate 10 for making the flow velocity distribution of the discharge air more uniform and sending an equal amount of air to each part in the barrel R. Air conditioning plate 1
0 is made of punching metal or the like. or,
The air conditioning plate 10 is an air blowing fan 9 as much as possible while having an air conditioning effect.
In general, the opening area for the ventilation air is configured to be as large as possible so as not to hinder the air blowing effect of the air conditioning system.
By providing the air conditioning effect and the blower fan 9
It is also configured to be able to adjust the air blowing effect of.

Next, the rich mixing portion O and the light mixing portion P will be described. Note that FIG. 4 shows two dense mixing portions O provided at intervals h and a light mixing portion P formed between the two dense mixing portions O.

The rich mixing section O is composed of a flat rectangular tubular body a. In the lower part of the rectangular tubular body a, a vertically long rectangular tubular inlet portion 1 is supplied with fuel gas and primary air for combustion.
1 is formed. The inlet part 11 is a rectangular tubular body a.
Is located above the air supply port 5a formed in the bottom plate 5 of the casing K in the state of being stored in the casing K.
A flat rectangular tube-shaped mixing portion 12 is formed on an upper portion of the inlet portion 11. In the mixing section 12, the fuel gas and the primary air for combustion are mixed. At the center of the mixing section 12, there is provided a throttle section 13 for making the distribution of the air-fuel mixture in the mixing section 12 more uniform.

A flame hole 1 for a rich air-fuel mixture is formed on the upper surface of the rectangular tubular body a. In the present embodiment, the flame holes 1 are composed of three sets of elliptical flame holes 1a, and eleven sets of flame holes are provided at an appropriate pitch for one square tubular body a. Therefore, the flame hole 1 as a whole is narrow in the second direction (M) and long in the first direction (L). Therefore, the fuel gas and the combustion primary air that have been supplied to the inlet portion 11 through the air supply port 5a rise in the inlet portion 11, are mixed and diffused in the mixing portion 12, and the flame hole 1
It is discharged from and forms a rich flame.

A straightening vane 14 for a light mixing portion P, which will be described later, is provided on both sides of the upper portion of the rectangular tubular body a. or,
At both ends of the upper surface of the rectangular tubular body a, blocking pieces 15 for blocking the direct blowing of the secondary air for combustion into the rich flame formed in the flame holes 1 located at both ends are provided. There is. The blocking piece 15 prevents unnecessary excess air in the rich flame located at the end, stabilizes the combustion state, and reduces CO in the exhaust gas. In this embodiment, the straightening plate 14 and the blocking piece 15 are integrally formed and fixed to the rectangular tubular body a at the side end portion of the rectangular tubular body a.

A notch 16 for inserting a retaining support piece 6c provided on the inner surface of a casing K, which will be described later, is formed at each side end of the rectangular tubular body a.

The light mixing section P is formed between the rich mixing section O and the dense mixing section O by accommodating a plurality of rectangular tubular bodies a in the casing K with the respective intervals h. To be done.
The air supply port 5b formed in the bottom plate 5 of the casing K is provided so as to be located between the adjacent rectangular tubular bodies a. Therefore, the fuel gas and the primary air for combustion supplied from the air supply port 5b rise in the light mixing portion P while being mixed and diffused in the light mixing portion P, and are provided above the light mixing portion P. After being rectified by the rectifying plate 14 existing therein, it is discharged from the flame hole 2 for the light air-fuel mixture formed between the upper surfaces of the two rectangular tubular bodies a to form a light flame.

The current plate 14 is a rectangular tubular body a located on both sides.
Both of the above are attached, so that one light mixing portion P is provided with two flow straightening plates 14. Light mixing part P
In the above, the rectifying plate 14 promotes the mixing of the fuel gas and the primary air for combustion, and prevents the flashback at the time of low input,
In addition, it is configured to have a flame holding effect of light flame. The upper end of the current plate 14 is the upper surface of the rectangular tubular body a, or
It is formed at the same height as the flame hole 2 of the light mixing portion P. The vertical width of the rectifying plate 14 promotes the mixing of the fuel gas and the primary air for combustion in a state where the flow resistance of the air-fuel mixture does not unnecessarily increase, and reduces the noise when the lean flame is burned. Is adjusted and formed.

The rectifying plate 14 is formed with a plurality of convex portions 14a, and the plurality of convex portions 14a form a gap between the rectangular tubular body a and the rectifying plate 14 and the rectifying plates 14 themselves. Configured to maintain a spacing between.

The casing K is composed of a bottom plate 5, and a side wall portion having a rectangular tubular shape formed by the plate-like body 6 and the plate-like body 7.

FIG. 5 shows a schematic structure of the casing K. As shown in FIG. 5, the side wall portion is substantially U-shaped in a plan view, and both sides of the U-shaped opening are formed. The plate-like body 6 bent to form the connecting portion 6d on the
Further, the plate-shaped body 7 is formed by connecting the both ends of the plate-shaped body 7 in close contact with the inner surface of the connecting portion 6d. The connecting portion 6d of the plate-shaped body 6 and the plate-shaped body 7 are connected by welding.

As shown in FIG. 3, on the surface of the plate-shaped body 6 located on the inner side of the casing K, there is a dropout for inserting into a notch 16 formed at the side end of the rectangular tubular body a. A stop support piece 6c is provided.

The above is the structure of the rich-lean combustion portion in the present application. In this combustion device, the rod-shaped obstacle member 100 for suppressing the generation of CO from the rich flame and the lean flame.
Is provided in the casing K so as to be located at the upper portion of the rich flame. The width of the rich air-fuel mixture flame hole 1 in the second direction M is 5 mm, and the rod-shaped obstacle member 100 is formed in a square shape having a cross section of 4 mm on a side, and is 20 mm from the flame hole end in the vertical direction. Is located in. Therefore, by arranging these rod-shaped obstacle members 100, it is possible to achieve a sufficient flame cooling effect to mix the gas between the rich flame and the lean flame, and achieve a complete combustion state and a low NOx combustion state. .

[Experimental Results] Now, with respect to the vertical arrangement position of the rod-shaped obstacle member with respect to the flame hole, the inventors
The results of the experiments conducted will be described. The experimental conditions are shown below. Gas flow rate Rich flame side Gas species Methane 10 liters / min Light flame side Gas species Methane 10 liters / min Rich flame side Air 50 liters / min
(Λ, 0.5) Light flame side Air 250 liter / min
(Λ, 2.5)

However, in such a rich / lean combustion apparatus, the primary air ratio of rich mixture with excessive fuel is 0.4 to 0.8.
By selecting the degree of fuel consumption and operating the fuel with the primary air ratio of the lean mixture of the lean mixture of 2.0 or more, the NOx rich and lean combustion can be most stably and satisfactorily performed. Thick mixture air flame width A 5 mm Light mixture air flame width D 5 mm Width of rod-shaped obstacles arranged on the rich mixture flame hole C 4 mm Arranged on the light mixture air flame hole Width of rod-shaped obstacle C 4 mm

The NOx reduction effect with and without the rod-shaped obstacles arranged side by side on the rich flame and the lean flame, and the results of examining the carbon monoxide production state are shown below. 1 When the bar-shaped obstacle member 100 is arranged on the rich flame When the distance from the flame hole to the heat dissipation member is B,
The relationship between B / A and the generated NOx [ppm] and CO / CO ₂ is shown in FIG. In the figure, the scale on the right side is the NOx [ppm] concentration, and the scale on the left side is CO / CO.
₂ shows the ratio. Further, the results when the obstacle of the present invention is not arranged on the rightmost side of the figure are shown by squares (NOx concentration) □ and circles (CO / CO ₂ ratio) ○. As a result, by arranging the heat-resistant material of the present application on the downstream side of the rich flame (eg, 2A <B <20A), the unburned components generated in the vicinity of the heat-dissipating body, which is difficult to burn, completes burning with lean flame. It can be seen that NOx can be reduced while preventing incomplete combustion. Further, when 2A <B <10A is selected, the generated CO can be suppressed close to the minimum value that can be achieved by the device. Further, if it is arranged up to 2A <B <6A, CO, N
Both Ox can be suppressed to a value near the minimum.

2 When Bar-shaped Obstacle Member is Arranged on Light Flame When E is the distance from the flame hole to the heat dissipation member,
The relationship between E / D and generated NOx [ppm] and CO / CO ₂ is shown in FIG. 7. In the figure, the scale on the right side is the NOx [ppm] concentration, and the scale on the left side is CO / CO.
₂ shows the ratio. Further, the results when the obstacle of the present invention is not arranged on the rightmost side of the figure are shown by squares (NOx concentration) □ and circles (CO / CO ₂ ratio) ○. As a result, by arranging the rod-shaped obstacle member of the present application on the downstream side of the lean flame (eg, 3D <E <30D), air is guided from the lean flame side to the rich flame side and combustion is completed in the rich flame. , While preventing incomplete combustion, N
It can be seen that Ox can be reduced. Furthermore, 3
When D <E <15D is selected, the generated CO and NOx can be suppressed close to the minimum value that can be achieved by the device. On the other hand, from the experimental results, not only to place the bar-like obstruction member on dark flame, be placed on a light flame, CO reducing effect, it can be seen that the obtained the NOx reduction effect. By the way, in the above experimental example, the width C of the rod-shaped obstacle member was set to be constant with respect to the width A (D) of the flame hole as the rod-shaped obstacle member, but this means that C / A (C / E) is 0. Even when it was changed in the range of 0.5 to 1.0, the effect was not significantly changed. When the width is larger than this width, there is a problem that combustion is disturbed, and when the width is smaller than this width, there is no effect as a radiator.

Another Embodiment Next, another embodiment will be described. In the above embodiments, an example in which the rod-shaped obstacle member is configured as a simple rod-shaped member has been shown, but it is preferable that such a member is made of a heat-resistant material such as ceramics or metal to ensure its life. In addition, if it is composed of either a pipe or a water pipe in which a fluid (cooling air, cooling water, etc.) flows inside, NOx reduction can be satisfactorily achieved with a long life, and the amount of the cooling fluid flowing in the pipe can be adjusted. You can adjust the cooling condition. Here, as the material, the object of the present application can be achieved even if the material has a low thermal conductivity, but if it is made high, the NOx reduction can be achieved by the flame cooling effect.

Further, in the rich / lean combustion device having no rod-shaped obstacle member of the conventional structure, combustion occurs in which the flame height is high in the central portion of the device in the second direction and the flame height is relatively low in both end portions thereof. However, if the width of the bar-shaped obstacle member is made wider toward the center side of the device in the second direction and narrower toward the end side, the above phenomenon (actually inappropriate mixing occurs). The rod-shaped obstacle member can more evenly average the amount of NOx and CO that are generated, and a rich-lean combustion device that can perform stable combustion can be obtained.

The hot and cold water heater, the fan heater and the like are most suitable for use in the rich / lean combustion device of the present application, but they can be used in any other burning device.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a density combustion device.

FIG. 2 is a vertical cross-sectional front view of a density combustion device.

FIG. 3 is a vertical sectional side view of the grayscale combustion device.

FIG. 4 is a perspective view showing a deep mixing portion and a light mixing portion.

FIG. 5 is a diagram showing a schematic configuration of a casing.

FIG. 6 is a diagram showing the relationship between the position in the height direction of a rod-shaped obstacle member and the amounts of CO and NOx generated.

FIG. 7 is a diagram showing the relationship between the height direction position of a rod-shaped obstacle member and the amounts of CO and NOx generated.

[Explanation of symbols]

 1 Flame mixture hole for rich mixture 2 Flame hole for light mixture 100 Rod-shaped obstacle member a Flame hole forming member K Casing L First direction M Second direction F1 Primary flame F2 Secondary flame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoya Fujimaru 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Within Osaka Gas Co., Ltd. (72) Inventor Hajime Toyonaga, 4-chome, Hirano-cho, Chuo-ku, Osaka-shi, Osaka 1-2 No. 2 in Osaka Gas Co., Ltd. (72) Inventor Shinobu Ishihara 1-152 Mina-shi Oka, Minato-ku, Osaka-shi, Osaka Prefecture 1-252 Herman Co., Ltd. (72) Inventor Ki-ichi Uemura 1-oka Oka, Minami-ku, Osaka-shi, Osaka Prefecture No. 1-52 Harman Co., Ltd.

Claims (7)

[Claims] 1. A casing (K) having a bottomed rectangular tube, inside a casing (K) having a second direction (M) which is long in a first direction (L) along an end face thereof and is orthogonal to the first direction (L). A plurality of flame hole forming members (a) forming narrow flame holes (1), (2) in the second direction (M), and the flame holes (1), (2) alternately in the second direction (M),
A rich / lean combustion device configured as a rich mixture flame hole (1) in which a rich fuel-air mixture burns and a light mixture flame hole (2) in which a lightly lean fuel-fuel mixture burns. A primary formed in the rich air-fuel mixture flame hole (1) on the lower side of either one of the plurality of rich-air mixture flame holes (1) or the plurality of light-air mixture flame holes (2). At a position in the secondary flame (F2) formed on the lower side of the flame (F1) and on the lower side of the both flame holes (1), (2), one flame hole lower side position to the other flame hole lower side A rich / lean combustion device in which rod-shaped obstacle members (100) for guiding combustion gas to a side position are arranged in parallel in the second direction (M). 2. The bar-shaped obstacle member (100) has a width approximately equal to the flame hole width in the second direction (M) of the corresponding flame holes (1), (2), respectively. 2. The rich / lean combustion device according to claim 1, wherein the rod-shaped member is longer than the flame hole length in one direction (L). 3. The primary air ratio of the rich fuel-rich air-fuel mixture is 0.4 to 0.8, and the primary air ratio of the lean air-fuel mixture in which the fuel is diluted is 2.0 or more. Item 1. The rich / lean combustion device according to Item 1. 4. The rich / lean combustion device according to claim 1, wherein the rod-shaped obstacle member (100) is a rod, a pipe or a water pipe made of a heat resistant material. 5. When the rod-shaped obstacle member (100) is arranged on the lower side of a plurality of the rich mixture flame holes (1), the rich mixture flame holes (1) in the second direction. When the width in (M) is A and the separation distance in the flame forming direction of the rod-shaped obstacle member (100) from the rich mixture flame hole (1) is B, A and B are 2 ×. The rich / lean combustion device according to claim 1, wherein A <B <20 × A. 6. A case where the rod-shaped obstacle member (100) is arranged on the lower side of the plurality of light-air mixture flame holes (2), and the second direction of the light-air mixture flame holes (2). When the width in (M) is D and the separation distance in the flame formation direction from the light-air mixture flame hole (2) of the rod-shaped obstacle member (100) is E, D and E are 3 ×. The rich / lean combustion device according to claim 1, wherein D <E <30 × D. 7. The primary flame (F1) formed in the rich mixture flame hole (1) is individually formed in each of the rich mixture flame holes (1) in the second direction (M). The secondary flame (F2) has a plurality of rich mixture gas flame holes (1) and a plurality of light mixture gas flame holes (2),
The rich / lean combustion device according to claim 1, wherein the flame holes (1), (2) are formed with a single flame surface on the lower side.