JPH0774685B2 - Combustion device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device, and more particularly to improvement of a combustion device adopting a rich and lean combustion system.

[0002]

2. Description of the Related Art In recent years, all primary air combustion or combustion close to it has been achieved in order to realize a compact and large capacity combustion device and to reduce the NOx in the exhaust gas to perform clean combustion. It is desired to develop a combustion device that adopts the method.

However, in this type of combustion apparatus, most of the air required for combustion is mixed with the fuel gas in advance, so the fuel gas concentration of the mixed gas is inevitably low, and lifting of the flame is likely to occur, so that a stable combustion range is obtained. It has the drawback of being narrow.

Therefore, as a measure to solve this problem, a supplementary flame portion for injecting and burning a mixed gas having a high concentration of the fuel gas is provided around the main flame portion having a lean fuel gas concentration, and the main flame is produced by the action of the supplementary flame. The dark and light combustion method for preventing the lifting of the above is attracting attention (Japanese Utility Model Laid-Open No. 2-36715, etc.).

FIG. 4 is a sectional view of a main part of a conventional combustion apparatus. In the conventional combustion apparatus, the flame hole plate 41 is placed on the gas distribution plate 40. That is, the inside of the gas distribution plate 40 is partitioned by the upper wall 45 and the lower wall 46, the inside is hollow, and the rich mixed gas distribution passage 48 is formed. A small hole 49 is provided on one surface of the upper wall 45. Further, the lower wall 12 is provided with an opening only at one end portion, and the rich mixed gas supply port 47 for supplying the mixed gas having a high concentration of the fuel gas into the rich mixed gas distribution passage 48.
Are formed.

Further, the gas distribution plate 40 has a large number of tubes 50.
Is inserted through the upper wall 45 and the lower wall 46 and is inserted into the tubular conduit 5.
1 is formed. The gas distribution plate 40 is fixed on the mixing box 52 such that the rich mixed gas supply port 47 matches the opening of the sub-mixing chamber 53 and the other parts match the main mixing chamber 54.
Here, the mixing box 52 is for mixing air and fuel gas in advance to form a mixed gas. In the main mixing chamber 54 of the mixing box 52, the main flame forming gas having a low concentration of the fuel gas forming the main flame is mixed, while in the sub mixing chamber 53, the auxiliary flame forming having a high concentration of the fuel gas forming the auxiliary flame is formed. The gases are mixed.

Therefore, the main flame forming gas that forms the main flame is injected from the pipe 50 of the gas distribution plate 40, while the supplementary flame forming gas that forms the supplementary flame is generated from the small holes 49 provided in the upper wall 45. Is jetted.

The flame hole plate 41 is a ceramic plate provided with innumerable round small holes penetrating both sides thereof, and is placed on the gas distribution plate 40. Therefore, the flame hole plate 4
A main flame 55 is generated in a portion corresponding to the upper pipe 50,
The supplementary flame 56 is generated in other portions.

A point to be noted in the structure of the combustion apparatus of the prior art is that the pipe 50 provided on the gas flow dividing plate 40 and injecting the main flame forming gas has a constant height. The back surface of the flame hole plate 41 was a flat plate. Then, it was common knowledge that the flame hole plate 41 was brought into contact with the tube 50 of the gas distribution plate 40 substantially without any gap.

[0010]

In the conventional combustion apparatus, the main flame lifting, which has been a conventional problem, has been solved by generating a stable supplementary flame with a high concentration of fuel gas around the main flame. It has the effect of being considerably improved. However, the combustion device of the prior art is not yet sufficiently satisfactory in terms of stability of the main flame, and there is room for further improvement.

That is, the function of the supplementary flame is to generate a stable flame around the main flame and prevent lifting of the main flame. The flame and the supplementary flame are formed as separate flames. As a result, there is a space between the main flame and the supplementary flame that has no flame, and the flame transfer from the supplementary flame to the main flame is poor, causing the main flame to lift.

In order to solve this problem, a groove may be formed on the surface of the flame hole plate to connect the main flame and the supplementary flame. However, this measure makes it difficult to form a groove on the surface of the flame hole plate. There was a problem in the processing called (Actual Kaihei 2-3671)
No. 5).

Further, the conventional flame hole plate has a flat plate-like back surface and does not have a mechanism for restricting the movement in the horizontal direction, so that the stability in the horizontal direction is poor and the flame hole plate is easily displaced. Therefore, the flame hole plate may move due to the vibration during combustion, and the distribution of the supplementary flame may change. As a result, the area of the supplementary flame that should be uniformly formed around the main flame becomes uneven depending on the location, and as in the situation described above, a space without any flame is generated between the main flame and the supplementary flame. ,
There was a problem that the main flame lifted.

As another problem, the flame hole plate must be positioned and fixed to the gas distribution plate so that the main flame and the supplementary flame are properly distributed. It required skill and was poor in work efficiency.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above-mentioned problems of the prior art, and to provide a combustion apparatus capable of forming a stable main flame without occurrence of lifting and having good workability in assembly. And

[0016]

A feature of the present invention for solving the above-mentioned problems is that a main flame forming gas, which is a mixed gas of fuel gas and air and has a low concentration of fuel gas, is injected. A flame hole plate with a large number of flame holes is placed on a gas distribution plate in which a large number of gas ejection ports and a rich gas ejection port for ejecting a flame-stabilizing gas whose fuel gas concentration is higher than the main flame-forming gas are arranged. In the burner described above, the flame hole plate has at least one fitting recess on the back surface, and at least one of the gas ejection ports is a convex gas ejection port projecting from other gas ejection ports. The jet port is fitted in the fitting concave portion of the flame hole plate, and is provided in the combustion device in which a gap is provided between the other gas jet port and the back surface of the flame hole plate.

[0017]

In the combustion apparatus of the present invention, the main flame forming gas having a low concentration of the fuel gas injected from the fresh gas ejection port passes through the flame holes of the flame hole plate and is ejected onto the flame hole plate to generate the main flame. generate. Similarly, the flame-strengthening gas injected from the rich gas outlet passes through the flame holes to generate flame-repair on the flame plate.

The difference between the combustion apparatus of the present invention and the conventional one is that since a gap is provided between the flame hole plate and the fresh gas jet port and the rich gas jet port, the fresh gas jet port and the rich gas jet port are different from each other. At the boundary portion of, the gases injected from the respective gas outlets are slightly mixed before reaching the flame hole plate. Therefore, in the combustion part on the flame hole plate, a gas having an intermediate concentration of both gases is ejected to a portion corresponding to a boundary between the light gas ejection port and the rich gas ejection port. As a result, the main flame and the supplementary flame are connected by the intermediate flame, and the blank portion does not occur.

In addition, since the convex gas ejection port is fitted in the fitting concave portion provided on the back surface of the flame hole plate, the flame hole plate is horizontally fixed integrally with the gas distribution plate. It Therefore, the movement of the flame hole plate during combustion is prevented, and the distribution of the supplementary flame does not change at all.

When assembling the combustion apparatus of the present invention, the flame hole plate can be positioned simply by aligning the convex gas jet ports of the gas flow dividing plate with the fitting recesses on the back surface of the flame hole plate and fitting them together. Complete.

[0021]

EXAMPLES Specific examples of the present invention will be described below. FIG. 1 is a front sectional view of a combustion apparatus according to a specific embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of the combustion device of FIG. FIG. 3 is an exploded perspective view of the combustion device of FIG.

In the figure, reference numeral 1 shows a combustion apparatus according to a specific embodiment of the present invention. The combustion device 1 according to the present embodiment includes a holding metal fitting 2, a flame hole plate 3, a gas distribution plate 4, a mixing box 5, and a front pipe 6.
Etc. The configuration of each member will be described below in order.

The holding metal fitting 2 is made by bending one thin steel plate, and the locking piece 1 is provided around the frame body 9.
0, the side wall 13, and the flame hole plate contact portion 15 are respectively formed.

The frame 9 of the holding metal fitting 2 is a frame that completely covers the upper end of the gas distribution plate 4, and has a large opening in the center. A locking piece 10 is provided downward on the entire short side of the frame 9. The locking piece 10 is provided with a rectangular hole 11 in the center. Two round holes 12 are provided on both sides of the hole, slightly below.

The side walls 13 are provided on the two long sides of the frame 9 and are low in height.

The flame hole plate abutting portions 15 are provided on the upper surface of the long side of the frame body 3 at intervals of three, and the bottom side is 2.
A small triangular plate of about 0 mm is bent and processed into a claw shape. That is, the flame hole plate abutting portion 15 has a rising portion 16 vertically raised from the frame body 9,
The rising portion 16 is bent downward at about 60 ° to form a hypotenuse portion 17, and the tip of the hypotenuse portion 17 is bent horizontally or arcuately to form a plate contact 18.

Since the cross section of the flame hole plate contact portion 15 is folded back into a claw shape, the rising portion 16 and the hypotenuse portion 17 have bending deformability. Therefore, the flame hole plate contact portion 15 has a considerable elastic force. That is, when a force is applied to the plate contact 18 from the bottom of the drawing upward, the rising portion 16 elastically warps outward. Similarly, the hypotenuse portion 17 is elastically deformed in the upward direction, and a downward repulsive force is generated in the plate contact 18 due to the elastic deformation of both.

The flame hole plate 3 is for ejecting a mixed gas of fuel gas and air and burning it on the upper surface. The flame hole plate 3 has a flat plate shape made of ceramics, and is a myriad of round small holes penetrating both sides. A flame hole is provided. As a characteristic structure of the flame hole plate 3 of this embodiment, a fitting recess 20 is provided on the back surface. The fitting recess 20 is a round recess and has a convex gas ejection port 3 of a gas distribution plate 4 having a diameter which will be described later.
3 is approximately equal to the diameter. Further, the depth is about 3 mm, and the position is provided on the back surface of the flame hole plate 3 and at a position slightly off the center.

The gas distribution plate 4 has the flame hole plate 3 placed thereon and distributes the mixed gas of the fuel gas and air evenly to make the flame of the flame hole plate 3 uniform in size. That is, in the gas distribution plate 4, a step 23 for mounting the flame hole plate 3 is provided inside a frame 22 made of aluminum die casting or the like, and a gas distribution path is formed below the step 23.

The combustion apparatus 1 of the present embodiment is premised on the adoption of a rich / lean combustion system in which a supplementary flame is generated around the main flame. The distribution passage for the main flame forming gas and the distribution passage for the supplementary flame forming gas. Are configured as separate flow paths. That is, the lower side of the step of the gas distribution plate 4 is partitioned by the upper wall 25 and the lower wall 26, and the inside is hollow to form a concentrated mixed gas distribution passage 27 through which the flame-restoring gas passes. Then, on the upper wall, a small-hole-shaped dense gas jet 28 for jetting the flame-strengthening gas is formed.
Is provided on one side. Further, the lower wall 26 is provided with an opening only at one end portion, and a rich mixed gas supply port 24 for supplying the main flame forming gas into the rich mixed gas distribution passage is formed.

A large number of tubes 29 are provided on the gas distribution plate 4.
The tubular pipe 30 is inserted through the upper wall 25 and the lower wall 26.
The upper portion of the pipe 29 projects from the upper wall 25 and opens to form a light gas ejection port 31. And it should be noted here that a large number of the pipes 2 of the fresh gas jet ports 31 are provided.
Only one of the nine pipes is higher than the other pipes and acts as a convex gas ejection port 33. Convex gas jet 33
The heights of the opening surfaces of the light gas ejection ports 31 other than the above are the same.

Here, the rich gas outlet 28 and the light gas outlet 3
1. When the height relationship of the convex gas jets 33 is summarized based on the step 23 of the gas distribution plate 4 described above, the convex gas jets 33 project above the step 23 of the gas distribution plate 4, and The fresh gas ejection port 31 of is 1 mm larger than the step of the gas distribution plate 4.
It is low. The height of the rich gas outlet 28 is lower than that of the light gas outlet 31.

The mixing box 5 mainly mixes air and fuel gas to mix a main flame forming gas and a supplementary flame forming gas. That is, the inside of the mixing box 5 is divided into a main mixing chamber 34 for producing a main flame forming gas having an excess air ratio of more than 1, and a sub mixing chamber 35 for producing a supplementary flame forming gas having a fuel gas concentration higher than the main flame forming gas. There is. The sub-mixing chamber 35 is composed of an elongated hole provided along one end of the mixing box 5.

The main mixing chamber 34 constitutes most of the mixing box 5 and is composed of all parts except the sub-mixing chamber 35 described above.
In this embodiment, the main mixing chamber 34 is largely divided into upper and lower parts by an upper and lower partition wall 36 having an opening 37 in the center,
The further lower part is divided into four sections by the partition 38.

The front tube 6 is a brass rectangular tube whose both ends are closed, and a gas connection port 39 is attached downward to one end. A large number of small holes 40 are provided on the upper side surfaces on both sides of the rectangular tube in the longitudinal direction.

Next, the connection relationship between the constituent parts described above will be described. The combustor 1 is installed in the lower compartment of the mixing box 5, and the gas distribution plate 4 has the rich mixed gas supply port 24 aligned with the sub mixing chamber 35 and the other portions aligned with the main mixing chamber 34 for mixing. It is fixed on the box 5.

The flame hole plate 3 is inserted into the frame 22 of the gas distribution plate 4 and placed on the step 23. At this time, the convex gas outlet 33 of the gas distribution plate 4 is fitted into the fitting recess 20 of the flame hole plate 3. Also, the convex gas ejection port 3
Since the tubes 29 and the upper wall 25 other than 3 are all lower than the step 23, the back surface of the flame hole plate 3 and the fresh gas ejection port 31
There is a gap 32 between the rich gas jet port 28.

In the pressing metal fitting 2, the lower surface of the frame body 9 is in close contact with the entire circumference of the upper end of the frame 22 of the gas distribution plate 4, and the locking piece 10 is provided.
The side wall 13 is in close contact with the outer periphery of the gas distribution plate 4 to cover the gas distribution plate 4. Then, the rectangular hole 11 of the locking piece 10 provided in the holding metal fitting 2 is engaged with the locking projection of the gas distribution plate 4, and the hole 12 of the locking piece 10 and the screw hole of the gas distribution plate 4 are aligned. Screw (not shown) is threadedly fastened, and the pressing member 2 is integrally connected to the gas distribution plate 4.

As a result, both the rising portion 16 and the oblique side portion 17 of the pressing member 2 are slightly deformed, and the flame hole plate abutting portion 15 moves the flame hole plate 3 to the gas distribution plate 4 by the repulsive elastic force of the deformation. I'm pushing it towards you.

Next, the operation of the combustion apparatus 1 of this embodiment will be described. In the combustion apparatus 1 of this embodiment, air is forcedly blown from the lower surface of the mixing box 5 by a fan (not shown).
The front pipe 6 is connected to a fuel gas supply passage (not shown),
Fuel gas is supplied. Then, the fuel gas is ejected horizontally from a large number of small holes 40 provided on the side surface of the front pipe 6 over a wide range.

The air forcedly supplied by the fan and the fuel gas ejected from the small holes 40 are mixed with the air in the main mixing chamber 34 and the sub-mixing chamber 35 at a predetermined ratio. That is, in the main mixing chamber 34, the fuel gas and air are mixed in each compartment,
Further, when passing through the openings 37 of the upper and lower partition walls 36, the airflow of each section collides with the airflow of the other sections and is completely mixed. Then, it enters the tube 29 of the gas distribution plate 4 and is blown from the light gas ejection port 31 toward the back surface of the flame hole plate 3.

On the other hand, in the sub-mixing chamber 35, the fuel gas is mixed with air at a higher ratio than in the main mixing chamber 34, and enters the rich mixed-gas distribution passage 27 from the rich mixed-gas supply port 24. Then, it is blown toward the back surface of the flame hole plate 3 from the rich gas outlet 28 provided in the upper wall 25.

Of the main flame forming gas, the gas ejected from the central portion of each light gas ejection port 31 passes through the flame holes of the flame hole plate 3 and is ejected onto the upper surface of the flame hole plate 3. However, the main flame forming gas in the peripheral portion of the fresh gas jet 31 is mixed with the flame-stabilizing gas ejected from the surrounding rich gas jets in the gap 32 between the fresh gas jet 31 and the flame hole plate 3. , The fuel gas has an intermediate fuel gas concentration and is ejected onto the upper surface of the flame hole plate 3. In addition, the flame-strengthening gas is directly ejected from other portions of the flame hole plate 3.

Therefore, in the flame on the flame hole plate 3, the main flame is formed at a position just above the fresh gas ejection port 31,
A supplementary flame is formed around the light gas ejection port 31, and an intermediate flame is generated between the two. Therefore, no break occurs between the main flame and the supplementary flame. Therefore, the transfer from the supplementary flame to the main flame is good.

Further, even if vibration occurs in the combustion device 1, the fitting concave portion 20 on the back surface of the flame hole plate 3 and the convex gas ejection port are fitted together, and the flame hole plate 3 has a flame of the pressing member 2. Since it is pressed downward by the hole plate contact portion 15, the flame hole plate 3 never moves. Therefore, the distribution of inflammation is also constant.

In the combustion apparatus of the present invention, the number of fitting recesses of the flame hole plate and the number of convex gas jets of the gas distribution plate are arbitrary. However, the most preferable number is the one shown in this embodiment. The reason for this is that the flame hole plate is usually made of ceramic or the like, and the variation in dimensional accuracy is relatively large. Therefore, if two or more fitting portions are provided on the flame hole plate, it is possible that the fitting concave portion and the convex gas ejection port do not coincide with each other during assembly.

In this embodiment, as a fixing means for the flame hole plate, a constitution in which a pressing metal fitting provided with an elastic flame hole plate abutting portion is arranged is illustrated. The configuration of this embodiment is
This is the most rational and recommended configuration as the flame hole plate fixing means adopted in the combustion apparatus of the present invention. That is,
In the combustion apparatus of the present invention, since the fitting concave portion of the flame hole plate and the convex gas jet port of the gas distribution plate are fitted to each other, the horizontal movement of the flame hole plate is prevented. Therefore, by pressing the flame hole plate with the elastic flame hole plate contact portion as in this embodiment, the vertical fixation of the flame hole plate is secured, and as a result, the flame hole plate is completely attached to the gas flow dividing plate. Fixed to.

[0048]

The combustion apparatus of the present invention has a very simple structure in which a gap is provided between the flame hole plate and the light gas outlet and the rich gas outlet. A gas having an intermediate concentration of both gases is ejected to a portion corresponding to the boundary of the ejection port to connect the main flame and the supplementary flame, and it is possible to prevent lifting of the main flame.

Further, in the combustion apparatus of the present invention, since the convex gas ejection port is fitted in the fitting concave portion provided on the back surface of the flame hole plate, the flame hole plate moves even if vibration is applied during combustion. There is nothing to do. Therefore, the combustion device of the present invention has no effect of changing the distribution of the supplementary flame due to vibration, can always generate stable supplementary flame around the main flame, and has an effect of effectively lifting the main flame.

In addition, in the combustion apparatus of the present invention, the flame hole plate can be easily positioned at the time of assembly, and the number of steps required for assembly can be reduced.

[Brief description of drawings]

FIG. 1 is a front sectional view of a combustion apparatus according to a specific embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the combustion device in FIG.

FIG. 3 is an exploded perspective view of the combustion device of FIG.

FIG. 4 is a cross-sectional view of a main part of a conventional combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion device 2 Holding metal fittings 3 Flame hole plate 4 Gas distribution plate 5 Mixing box 15 Flame hole plate contacting portion 20 Fitting concave portion 23 Step 28 Rich gas jet 29 Pipe 31 Fresh gas jet 32 Gap 33 Convex gas jet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidehisa Hashimoto 32 Akashi-cho, Chuo-ku, Hyogo Prefecture Noritsu Co., Ltd. (56) References: Kaihei Hei 2-36716 (JP, U)

Claims (1)

[Claims] 1. A fresh gas injection port for injecting a main flame forming gas, which is a mixed gas of fuel gas and air and has a low concentration of fuel gas, and a supplementary flame formation, in which the concentration of fuel gas is higher than that of the main flame forming gas. In a combustion device in which a flame hole plate having a large number of flame holes is placed on a gas distribution plate having a large number of dense gas outlets for ejecting gas, the flame hole plate has at least 1 on the back surface.
Has one fitting recess, at least one of the gas outlets is a convex gas outlet projecting more than the other gas outlets, and the convex gas outlet is fitted with the fitting recess of the flame hole plate. A combustion device characterized in that a gap is provided between the other gas ejection port and the back surface of the flame hole plate.