JPH06300229A - Thick-and-thin fuel combustion device - Google Patents

Abstract

PURPOSE:To stabilize combustion state while noise generation and the load on a fan are reduced, by providing flow equalizing plates whose upper edges protrude upward beyond burner ports. CONSTITUTION:Flow equalizing plates 14 are attached on both upper side faces of a square tubular body (a) to equalize the flow of thin air-fuel mixed gas that flows toward burner ports 2 of thin-fuel mixing sections B. As the flow equalizing plates 14 are attached on both the square tubular bodies (a) located on both sides, each of the thin-fuel mixing section B is provided with two flow equalizing plates 14. The upper edge of the flow equalizing plate 14 protrudes upward beyond the burner port 2, and the height (h) of the flow equalizing plate 14 above the burner port 2 is determined according to an equation 0<=(h)<=(d)/2, where (d) is a distance between the two adjacent square tubular bodies (a). Thereby, a back fire and an interference with the thick-fuel flames in the thin-fuel mixing sections B can be prevented while generation of noise and the load of an air fan are reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat dense mixing section for producing a rich air-fuel mixture having a small primary air suction ratio and a flat-shaped lean mixture for producing a light air-fuel mixture having a large primary air suction ratio. Parts are alternately arranged, a flame hole for a rich air-fuel mixture is formed on the upper surface of the rich mixing portion, a flame hole for a light air-fuel mixture is formed on the upper surface of the light mixing portion, the light mixing portion, The present invention relates to a rich / lean combustion device provided with a straightening vane that straightens the lean air-fuel mixture flowing toward the flame holes.

[0002]

2. Description of the Related Art Conventionally, in this type of rich / lean combustion device,
The baffle plate is provided so that its upper end is at the same height as the flame hole or its upper end is lower than the flame hole.

[0003]

However, according to the above-mentioned prior art, when the vertical width of the straightening vane is shortened in order to reduce the passing pressure loss in the light mixing portion, the suction ratio of the light mixing portion is relatively small ( During combustion (when the excess air ratio is reduced), a lean flame is formed in the vicinity of the flame hole, which interferes with the rich flame in the rich mixing section to make the combustion state unstable and generate resonance noise. However, the quenching effect (cooling effect) is also reduced, and there is a disadvantage that flashback is likely to occur.

In order to prevent the above inconvenience, if a straightening plate having a relatively long vertical width is used, the passing pressure loss increases, so that noise is generated and the load of the blower fan is increased. There is.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks.

[0006]

A first characteristic structure of the rich-lean combustion device according to the present invention is that the straightening vane is provided with its upper end protruding above the flame holes.

A second characteristic configuration of the rich-lean combustion device according to the present invention specifies a preferred specific configuration for carrying out the first characteristic configuration. The flat rectangular tubular bodies of are housed in a state of being arranged at intervals, and the dense mixing portion is formed by the rectangular tubular bodies, and
The light mixing portion is formed in a space surrounded by the side walls of the rectangular tubular body and the casing that are adjacent to each other, and the straightening plate is
The point is that it is attached to the rectangular tubular body.

[0008]

According to the first characteristic configuration of the present invention,
Since the upper end thereof is provided so as to project above the flame holes, it is difficult for the light flame to be formed in the vicinity of the flame holes even during combustion when the suction ratio of the light mixing portion is relatively small. Further, even if a flashback is likely to occur, it becomes difficult for the flame to enter the flame holes.

According to the second characteristic configuration, the dense mixing portion is formed by the rectangular tubular body, and the light mixing portion is formed by the space surrounded by the side walls of the adjacent rectangular tubular body and the casing. Since the straightening vanes are attached to the rectangular tubular body, the rich mixing portion and the light mixing portion are alternately formed with a simple structure, and the flame holes of the rich mixing portion are at the same height as that of the rich mixing portion. Also, even when the flame hole of the light mixing portion is formed in the portion surrounded by the upper end of the casing side wall, the straightening vane can be provided in the light mixing portion.

[0010]

According to the first characteristic configuration of the present invention, the lean flame is less likely to be formed in the vicinity of the flame hole even during the combustion when the suction ratio of the lean mixing portion is relatively small, and the flashback occurs. Even if it is likely to happen, the flame will not easily enter the flame holes, so by reducing the vertical width of the straightening vanes and reducing the passing pressure loss in the light mixing section, noise is generated and the burden on the blower fan is reduced. (EN) Provided is a rich-lean combustion device in which the flow straightening plate effectively prevents interference with a backfire or a rich flame in a lean mixing section, stabilizes a combustion state, and does not generate resonance noise. You can

According to the second characteristic configuration, the dense mixing portions and the light mixing portions are alternately formed, and are at the same height as the flame holes of the rich mixing portion and at the flame holes of the rich mixing portion and the upper end of the casing side wall. Even when the flame holes in the light mixing section are formed in the enclosed area, the straightening plate can be provided in the light mixing section, so the structure is simple, and the flame holes and light holes in the rich mixing section are formed. Even when the flame holes in the mixing section are formed at the same height and in close proximity to each other, the straightening vane effectively prevents the backfire and the interference with the rich flame in the lean mixing section from being effectively prevented. Can be provided.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a flat-shaped rich mixing portion A that produces a rich air-fuel mixture with a small primary air suction ratio and a flat-shaped lean mixing portion B that produces a light air-fuel mixture with a large primary air suction ratio are alternated. The rich-lean combustion device is shown in which the flame mixture hole 1 for the rich mixture is formed on the upper surface of the rich mixing portion A, and the flame hole 2 for the light mixture is formed on the upper surface of the light mixing portion B. .

The rich / lean combustion device maintains the ignitability and the flame holding effect by the rich flame, and at the same time, burns a desired amount of combustion in a state where the combustion temperature is lowered by the lean flame, whereby NO _x ( This is a combustion device capable of performing combustion with the generation of nitrogen oxides reduced as much as possible.

The rich / lean combustion device in this embodiment is composed of a so-called Bunsen burner. The rich mixing section A and the light mixing section B are housed in a casing K in the shape of a square cylinder with a bottom arranged alternately. The rich flame is above the flame hole 1 provided in the rich mixing section A, and the lean flame is the lean mixing section B.
Are formed above the flame holes 2 provided in each. The casing K includes a bottom plate 5, a burner fixing plate 6 as a side wall of the casing K, and a side plate 7. In the bottom plate 5 of the casing K, there are provided a rich mixing supply port 5a and a light mixing supply port 5b corresponding to the rich mixing part A and the light mixing part B, respectively, and an opening area of the light mixing supply port 5b. Is larger than the opening area of the supply port 5a for dense mixing. Below the bottom plate 5, a supply port 5a for deep mixing is provided.
Of concentrated fuel gas for dense mixing, which is provided with an ejection nozzle 3a as an ejecting portion for ejecting fuel gas toward the air, and ejection as an ejecting portion for ejecting fuel gas toward the supply port 5b for light mixing Two light fuel gas supply pipes 4 for light mixing provided with nozzles 4b are provided. Therefore, the supply port 5a and the supply port 5 are provided to the dense mixing section A and the light mixing section B, respectively.
The fuel gas is blown through b, and the primary combustion air is sucked with it.

A casing K for accommodating the rich mixing portion A and the light mixing portion B, 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 a 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 barrel R and the casing K.
Are formed. The gap 8 is configured to have the effect of cooling the casing K by the flow of the cooling air and blocking the heat from the casing K with respect to the barrel R.

At the bottom of the barrel R, a blower fan 9 for blowing combustion air and cooling air toward the bottom plate 5 and the gap 8.
Fan outlet 9a is provided. Fan outlet 9
In a, the flow velocity distribution of the discharge air is made more uniform,
An air rectifying plate 10 for blowing an equal amount of air is provided to each part inside. The air conditioning plate 10 is made of punching metal or the like. Further, the air conditioning plate 10 is generally configured so that the opening area for the ventilation air is as large as possible so as not to hinder the air blowing effect of the air blowing fan 9 while exhibiting the air conditioning effect. By narrowing the area or providing multiple air conditioning boards 10,
The air conditioning effect and the air blowing effect of the air blowing fan 9 can be adjusted.

FIG. 2 shows two dense mixing sections A and the two
The light mixing section B formed between the dense mixing sections A of the sheet is shown. The rich mixing portion A 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 11 is formed for supplying fuel gas and primary air for combustion. The inlet portion 11 is configured to be located above the air supply port 5a formed in the bottom plate 5 of the casing K when the rectangular tubular body a is housed 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 this embodiment, the flame holes 1 are formed by a set of three elliptical flame holes 1a, and eleven flame holes 1 are provided for one square tubular body a at an appropriate pitch. Therefore, the fuel gas and the combustion primary air, which 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 are discharged from the flame hole 1. Forms a rich flame.

On both side surfaces of the upper portion of the rectangular tubular body a, there are attached rectifying plates 14 for rectifying the light air-fuel mixture flowing toward the flame holes 2 of the light mixing portion B, which will be described later.

As shown in FIG. 3, the light mixing section B has a plurality of flat rectangular tubular bodies a inside a rectangular tubular casing K with a bottom.
By being stored in a state in which the
It is formed in the space surrounded by the adjacent rectangular tubular body a and the burner fixing plate 6 as the side wall of the casing K, and the rich mixing portion A is formed.
And the dense mixing portion A. The air supply port 5b formed in the bottom plate 5 of the casing K is provided so as to be located between the rectangular tubular bodies a. Therefore,
The fuel gas and the primary air for combustion supplied from the air supply port 5b are mixed and diffused in the light mixing portion B while being mixed in the light mixing portion B.
After rising in the inside and being rectified by the rectifying plate 14 provided on the upper portion of the light mixing portion B, the flame holes for the light mixture formed between the upper surface portions of the two rectangular tubular bodies a. It is discharged from 2 and forms 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 section B is provided with two straightening vanes 14. Light mixing section B
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 formed so as to project above the flame holes 2. In the rich / lean combustion device of the present embodiment, the height h of the straightening vane 14 protruding above the flame holes 2 is 0 ≦ h ≦, where d is the width at which two adjacent rectangular tubular bodies a are separated from each other. It is adjusted to d / 2.

The vertical width of the rectifying plate 14 is such that the mixing of the fuel gas and the primary air for combustion is promoted and the lean flame is promoted in a state where the passage pressure loss due to the flow resistance of the lean air mixture does not unnecessarily increase. Is adjusted so that the noise during combustion is low.

A plurality of convex portions 14a are formed on the straightening vane 14 so as to abut against the rectangular tubular body a and the other straightening vane 14 so that the space between the rectangular tubular body a and the straightening vane 14 is abutted. Interval of
In addition, it is configured to maintain the space between the straightening vanes 14. The distance between the rectangular tubular body a and the rectifying plate 14 and the distance between the rectifying plates 14 are adjusted to dimensions effective for the rectifying plate 14 to exert a quenching effect (cooling effect) in a lean flame. ing.

[Other Embodiments] The height h of the straightening vane 14 projecting above the flame holes 2 is not limited to 0 ≦ h ≦ d / 2, and can be appropriately changed.

Further, the current plate 14 is not limited to one formed substantially parallel to the side surface of the rectangular tubular body a, and a plurality of fins are provided vertically from the side surface of the rectangular tubular body a. Anything is fine.

The number of rectifying plates 14 can be changed appropriately.

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

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall structure of a rich-lean combustion device.

FIG. 2 is a perspective view showing a deep mixing section and a light mixing section.

FIG. 3 is a cross-sectional view showing a deep mixing portion and a light mixing portion.

[Explanation of symbols]

 A dense mixing section B light mixing section K casing a square tubular body 1 flame hole 2 flame hole 6 side wall 14 straightening plate

Claims (2)

[Claims] 1. A flat-shaped rich mixing portion (A) for producing a rich air-fuel mixture having a low primary air suction ratio, and a flat-shaped light-mixing portion (B) for producing a light air-fuel mixture having a high primary air suction ratio. ) Are alternately arranged, a flame hole (1) for a rich air-fuel mixture is formed on the upper surface of the rich mixing portion (A), and a flame hole for a light air-fuel mixture (1) is formed on the upper surface of the light mixing portion (B). 2) is formed, and the lean mixing unit (B) is provided with a rectifying plate (14) for rectifying the lean air-fuel mixture flowing toward the flame hole (2). A rich-lean combustion device in which the straightening vane (14) is provided with its upper end projecting above the flame holes (2). 2. A plurality of flat rectangular tubular bodies (a) are accommodated in a bottomed rectangular tubular casing (K) in a state of being arranged side by side with a space therebetween. The dense mixing portion (A) is formed in the light mixing portion (B) in the space surrounded by the side wall (6) of the rectangular tubular body (a) and the casing (K) which are adjacent to each other. ) Is formed, and the straightening vane (14) is attached to the rectangular tubular body (a).