JPH11230509A - Dense and light combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dense and light combustor which can be made compact and in which excessive heating of wall in a combustion chamber due to dense flame can be prevented without increasing the quantity of cooling air extremely. SOLUTION: This combustor is provided with flat thick mixing parts 5 and thin mixing parts 13, which are alternately arranged side by side in the widthwise direction and housed and held in a square casing 3 in a manner that the thick mixing parts are positioned at both ends, and a clearance 15 is formed between the thick mixing parts 5 at both ends in the side-by-side direction and the casing 3, thereby ventilating a secondary air for combustion toward the upper side. The casing 3 is housed in a combustion chamber 2 apart from a clearance 4 for forming a cooling air route in its outer periphery, thereby ventilating the cooling air toward the upper side. Further, in the casing 3, the upper ends of walls 3a opposite respectively to the thick fuel combustion parts 5 at both ends in the side-by-side direction are located above the burner port 6 for thick mixing gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a flat rich mixing section in which a flame hole for rich mixture is formed above, and a flat light mixing section in which a flame hole for light mixture is formed above, The width direction is alternately set as the juxtaposition direction, and the enrichment portions are juxtaposed so that the enrichment portions are located at both ends, are stored and held in a rectangular casing in plan view, and enrichment portions located at both ends in the juxtaposition direction. A space is formed in the juxtaposition direction between the portion and the casing, and the secondary air for combustion is configured to flow upward through the space, and the casing is
The present invention relates to a concentration combustion apparatus which is accommodated in a combustion chamber with a space for forming a cooling air passage around the outside thereof and is configured so that cooling air flows upward through the cooling air passage.

[0002]

2. Description of the Related Art In a rich / lean combustion apparatus having such a structure, a rich flame generated in a rich mixture flame is located on both sides of a lean flame generated in a lean mixture flame. Under the flame holding action, it is possible to perform favorable lean combustion while suppressing the generation of NOx. By the way, conventionally, in such a lean-burn combustion apparatus, as shown in FIG. It is configured so as to be located lower than the hole 6 or the flame hole 14 for the light mixture, or to be located at substantially the same height as the flame hole 6 for the rich mixture or the flame hole 14 for the light mixture. Was composed.

[0003]

Therefore, particularly at the end of the rich mixing section 5 and the light mixing section 13 in the juxtaposition direction, the flame for the rich mixture of the rich mixing section 5 located at the end thereof. Hole 6
The wall of the combustion chamber 2 is heated by the rich flame indicated by the phantom line in the figure, and the temperature inside the combustion chamber 2 rises abnormally. That is, in order to make the entire combustion apparatus compact, it is advantageous to reduce the distance 4 between the wall 3A of the casing 3 and the wall of the combustion chamber 2. In this case, even if the wall 3B of the casing 3 and the wall of the combustion chamber 2 are close to each other at the ends of the flat rich mixing section 5 and the light mixing section 13 in the longitudinal direction, the thick 3 A member for holding the rich mixing portion 5 and the like is interposed between the mixing portion 5 and the like, or it is structurally difficult to form the rich mixture air hole 6 near the end. For this reason, a certain distance is maintained between the flame and the wall of the combustion chamber 2. However, at the end in the juxtaposition direction, since the rich mixture flame hole 6 and the wall of the combustion chamber 2 are close to each other, the wall of the combustion chamber 2 is abnormally heated by the radiant heat of the rich flame. There was a problem.

In order to solve such a problem, the distance 4 between the wall 3A of the casing 3 and the wall of the combustion chamber 2 may be increased.
In order to improve the cooling effect by increasing the amount of cooling air flowing between the casing 3 and the wall of the combustion chamber 2, the size of the fan for passing the cooling air increases, There are other problems, such as the increase in noise with the increase in size, and in addition, CO is generated by disturbance of the rich flame due to the cooling air flowing at high speed,
There is a problem that the flame holding action against the light flame is inhibited.

The present invention focuses on such various problems in the prior art. The purpose of the present invention is to make it possible to make the apparatus compact and without significantly increasing the amount of cooling air. It is an object of the present invention to provide a lean-burn combustion apparatus capable of preventing excessive heating of a combustion chamber wall by a rich flame.

[0006]

According to the first aspect of the present invention, there is provided a casing in which a flat rich mixing section and a light mixing section are stored and held side by side. Since the wall facing each of the rich combustion portions located at both ends of the direction in the juxtaposed direction is configured so that its upper end is located above the rich mixture flame hole,
The casing wall located above the rich mixture flame is
It blocks the radiant heat of the rich flame generated in the rich mixture flame hole, suppresses the heating of the combustion chamber wall, and prevents the disturbance of the rich flame due to the cooling air flowing outside the casing wall. As a result, it is possible to reduce the size of the combustion device, and without excessively increasing the amount of cooling air, to excessively heat the wall of the combustion chamber opposed to the rich combustion portions located at both ends in the juxtaposition direction. Thus, the generation of CO due to the disturbance of the rich flame is suppressed, and the flame holding action against the light flame can be expected.

According to the second aspect of the present invention, the wall of the casing, which is located along the juxtaposition direction,
Since the upper end thereof is configured to be located above the flame for the rich mixture and the flame for the lean mixture, in addition to the walls of the combustion chamber opposed to both ends in the above-mentioned arrangement direction, it is arranged in parallel. Even in the combustion chamber walls along the direction, excessive heating is prevented by the radiant heat shielded by the casing wall located above the rich mixture air hole and the light mixture air hole, and the temperature inside the combustion chamber rises. Is further suppressed.

According to the third aspect of the invention, the rich burner constituting the rich mixing section is housed and held in the casing, and the light mixing section is formed by the dense burner and the casing adjacent in the juxtaposed direction. Since it is formed, the member constituting the rich burner can also be used as the member for forming the light mixing section, so that the weight of the combustion device can be reduced in addition to the compactness described above.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a concentration combustion apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1 and FIG. 2, the light-and-dark combustion apparatus is entirely covered with a rectangular outer frame 1 in a plan view, and a combustion chamber 2 formed inside the outer frame 1 has a flat surface. The burner casing 3, which is rectangular when viewed, is stored and held with a space between the four side walls and the inner wall surface of the outer frame 1, and the space formed around the outer periphery of the burner casing 3 is cooled. The cooling air passage 4 is formed to allow the working air to flow upward, and a plurality of rich burners 5 are housed and held in the burner casing 3.

The rich burner 5 constitutes a rich mixing section for discharging and burning a rich air-fuel mixture having a small air mixing ratio, and is entirely formed in a flat shape by a sheet metal. As shown in FIG. 3, a rich mixture flame 6 composed of a plurality of slits is formed along the longitudinal direction, and a rich mixture chamber 7 communicating with the rich mixture flame 6 and a rich mixture chamber 7. Is provided with a concentration inlet 8 for introducing fuel gas and combustion air. The rich burner 5 further includes a lean gas passage 9 for supplying a mixture of fuel gas and combustion air to a lean mixing section described later, and a fuel gas and combustion air flowing through the lean gas passage 9. The gas inlet 9 is provided with a light introduction port 10 for introducing the gas, and a large number of ejection holes 11 are formed in the light gas passage 9.

With such a rich burner 5 having the flame hole 6 for rich mixture positioned above, the width direction of the burner 5 is set as a parallel direction, and the burner 5 is spaced at a constant interval in the parallel direction. By being stored and held in the burner casing 3 and arranging a plurality of dark burners 5 side by side at fixed intervals in this manner, a flat space is formed by the dark burners 5 and the burner casing 3 which are adjacent in the juxtaposition direction. This flat space is used as the light mixing chamber 12.
Thus, a light mixing section 13 for discharging and burning a light mixture having a high air mixing ratio is formed, and a light mixture gas hole 14 between the adjacent rich mixture flames 6 of the dense burner 5 is formed. Are formed.

As a result, the flat rich burner 5 having the rich mixture gas flame 6 at the top and the flat light mixing section 13 having the light mixture flame 14 at the top have a widthwise direction. The dark burners 5 are alternately arranged in the juxtaposition direction such that the dark burners 5 are located at both ends.
And a wall 3a of the burner casing 3 opposed to the rich burner 5 located at both ends thereof, a space 15 is provided between the burner casing 3 and the combustion air. Is configured.

A cover plate 16 made of sheet metal having substantially the same shape as the side surface of the dark burner 5 is located on one lateral side of the dark burner 5. Caulked and attached to the burner 5 and the dark burner 5
A plurality of sheet metal rectifying plates 17 positioned between the cover plate 16 and the cover plate 16 are attached together by caulking.
And the upper end of each straightening plate 17 is located at substantially the same height as the rich mixture flame 6. However, in the dark burner 5 located at the end in the juxtaposition direction,
Since a space 15 for secondary air ventilation for combustion is formed on the lateral side, one of the dense burners 5, in this embodiment, the rightmost dense burner 5 in FIG. The flow straightening plate 17 is not attached, and the light emitting gas passage 9 formed in the dense burner 5 has the ejection hole 11.
Also not drilled.

Such a dense burner 5 has its longitudinal ends disposed in slits 18a provided in a holding member 18 provided continuously inside a wall 3b of the burner casing 3 which is located along the juxtaposed direction. The upper ends of the four side walls 3a and 3b of the burner casing 3 are inserted and held from above.
All of them extend so as to be located higher than the rich mixture gas flame hole 6 of the rich burner 5 and the light mixture gas flame hole 14 of the light mixing section 13. That is, the upper end of the wall 3a of the burner casing 3 which is opposed to each of the dark burners 5 positioned at both ends in the juxtaposition direction of the dark burner 5 is formed by the flame hole 6 for the rich mixture.
The upper end of the wall 3b of the burner casing 3 which extends so as to be higher than the upper side and is located along the direction in which the rich burner 5 is juxtaposed is also provided with the rich mixture flame hole 6 and the light mixture flame hole 14.
It is extended so that it may be located above.

At the bottom of the burner casing 3, a perforated plate 19 having a large number of holes for air conditioning is provided, and an air chamber 20 is formed between the perforated plate 19 and the bottom of the outer frame 1. The air chamber 20 communicates with the mixing chambers 12 for lightening and the space 15 for secondary air ventilation for combustion through holes in the perforated plate 19, and the cooling air passages 4 through four openings.
Is communicated to. And below the outer frame 1,
Fan 21 for supplying combustion air and cooling air
The discharge port of the fan 21 is communicated with the air chamber 20, and the combustion air is supplied to each of the light mixing chambers 12 and the interval 15 through the air chamber 20, and the cooling air passage 4 is provided. It is configured to supply cooling air to the.

The dark inlet 8 and the light inlet 10 provided in each dark burner 5 are all arranged side by side in the same direction.
A gas header 22 for distributing and supplying the enriched fuel gas and the lean fuel gas is provided on the front surface thereof, and the enriched gas nozzle 23 attached to the gas header 22 is provided with each enrichment inlet 8.
In addition, the lean gas nozzle 24 faces each of the lean inlets 10, and a part of the air from the air chamber 20 is separated at a predetermined ratio by the ejector action by blowing the fuel gas from each of the gas nozzles 23 and 24. It is configured to be sucked and introduced into each of the inlets 8 and 10. A gas supply path 25 is connected to the gas header 22. The gas supply path 25 is provided with an opening / closing valve, a gas amount adjusting valve, and the like. The amount of fuel gas supplied to the supply gas nozzle 24 is adjusted to obtain a desired heating amount.

More specifically, the combustion gas supplied to the gas header 22 from the gas supply passage 25 is blown from each rich gas nozzle 23 into the rich inlet 8 and from each lean gas nozzle 24 into the lean inlet 10. At this time, a part of the air from the air chamber 20 is sucked at a predetermined ratio as combustion air by an ejector action at that time.
0 is introduced. The fuel gas and the combustion air introduced into the rich inlet 8 are mixed in the rich mixing chamber 7 to generate a rich air-fuel mixture having a small air mixing ratio, and the rich air-fuel mixture is used as a rich air-fuel mixture flame. The fuel is discharged from the hole 6 and burned to generate a rich flame. Further, the fuel gas and the combustion air introduced into the lean gas inlet 10 pass through the lean gas passage 9 to form a large number of jet holes 1.
1 to the mixing chamber 12 for light,
9 is mixed with the combustion air supplied through 9 to generate a lean air-fuel mixture having a high air mixing ratio, and the lean air-fuel mixture is discharged from the lean air-fuel mixture flame 14 and burned to generate a lean flame. At the same time, it burns favorably due to the flame holding effect of the rich flame generated on both sides.

At the time of the concentration combustion, a part of the air blown by the fan 21 flows upward through the space 15 through the hole of the perforated plate 19 forming the air chamber 20, and flows in the parallel direction. The rich mixture flame holes 6 located at both ends are supplied as combustion secondary air for the rich flame generated. At the same time, a part of the air blown by the fan 21 flows upward in the cooling air passage 4 and the wall 3 of the burner casing 3.
a, 3b and the wall of the outer frame 1 forming the combustion chamber 2 are cooled,
Moreover, the walls 3a and 3b of the burner casing 3 located above the rich mixture gas flame 6 and the light mixture gas flame 14 block the radiant heat due to the rich flame or the light flame, and the wall of the outer frame 1 is formed. This suppresses the heating of.

[Other Embodiments] (1) In the above embodiment, a plurality of dense burners 5 are housed and held in the burner casing 3 at regular intervals, and a flat space formed thereby is used. Although the example in which the light mixing section 13 is configured is shown, a flat light burner having the same configuration as the rich burner 5 is provided, and the rich burner 5 and the light burner are alternately arranged side by side to constitute a rich-burn combustion apparatus. You can also.

(2) In the above embodiment, an example was shown in which all of the four side walls 3a and 3b of the burner casing 3 were extended upward, but the dark burners located at both ends in the direction in which the dark burners 5 are arranged side by side. Only the upper end of the wall 3a of the burner casing 3 facing each other along the longitudinal direction of the burner
It can also be carried out by extending it upward.

(3) In the above-described embodiment, the four side walls 3a and 3b of the burner casing 3 are integrally extended upward. All of the wall portions extending above the holes 14, or
Part of the burner casing 3 may be configured separately from the burner casing 3 to be fixed to the burner casing 3. In this case, a wall portion configured separately from the burner casing 3 may be formed of, for example, a heat-resistant separate part. It can also be composed of a material.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional side view of a concentration combustion device.

FIG. 3 is a plan view of the concentration combustion device.

FIG. 4 is a vertical sectional front view of the concentration combustion device.

FIG. 5 is a vertical cross-sectional front view showing a conventional structure of a concentration combustion apparatus.

[Explanation of symbols]

 Reference Signs List 2 Combustion chamber 3 Casing 3a, 3b Casing wall 5 Rich burner as rich mixing section 6 Flame hole for rich mixture 13 Light mixing section 14 Flame hole for lean mixture 15 Interval

Claims (3)

[Claims] 1. A flat rich mixing portion having a rich mixture gas flame formed thereon and a flat light mixing portion having a light mixture gas flame formed thereon are arranged side by side in the width direction. Alternating direction
And, the rich mixing sections are arranged side by side so as to be located at both ends, are stored and held in a rectangular casing in plan view, and between the rich mixing sections located at both ends in the juxtaposition direction and the casing,
An interval is formed in the juxtaposed direction, and the secondary air for combustion is configured to flow upward through the interval, and the casing forms a cooling air passage around its outer periphery. A light-and-dark combustion apparatus that is housed in a combustion chamber at an interval, and is configured such that cooling air flows upward through the cooling air passage. A rich-burn combustion apparatus, wherein a wall facing each of the located rich combustion sections in the juxtaposed direction has an upper end located above the rich mixture flame hole. 2. The casing according to claim 1, wherein a wall of the casing located along the juxtaposition direction has an upper end positioned above the flame of the rich mixture and the flame of the lean mixture. Item 1. A concentration combustion apparatus according to Item 1. 3. The light mixing section is stored and held in the casing, and the light mixing section is formed by the thick burner and the casing adjacent in the juxtaposition direction. 3. The concentration combustion device according to 2.