JP3242366B2 - Combustion equipment - 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 apparatus suitable for home use and small business use.

[0002]

2. Description of the Related Art Combustion gas generated by burners of various combustion apparatuses contains nitrogen oxides (NOx).
Is harmful to the human body and is said to be released into the atmosphere, causing acid rain and photochemical smog. For this reason, various measures have been taken to reduce the amount of NOx generated in burners to be used in combustion devices.

[0003]

The conventional countermeasures are for a large-sized combustion device for industrial use or the like, which is legally regulated. Therefore, it cannot be said that sufficient measures have been taken. In a large combustion device, since the static pressure of the combustion fan can be increased, the flow of combustion gas and air can be easily controlled, the layout of the burner has a high degree of freedom, and noise control is easy. Since the conditions for countermeasures are not strict and the combustion chamber can be made large, complete combustion is easy even if a measure for reducing NOx by so-called slow combustion is taken. On the other hand, a small-sized combustion device cannot take a large static pressure of a combustion fan, it is difficult to control the flow of combustion gas and air, and the degree of freedom in the burner layout is low.
Noise countermeasures are troublesome, noise control conditions are severe,
In addition, since a large combustion chamber cannot be provided, it is difficult to reduce NOx as compared with a large combustion device.

Accordingly, an object of the present invention is to provide a combustion apparatus in which combustion is enhanced to suppress generation of nitrogen oxides and reduce noise.

[0005]

A combustion apparatus according to the present invention comprises a first burner (burner unit 1a) for burning a first fuel-lean mixture, and a second burner for burning a second fuel-rich mixture. A burner (burner unit 1b) for simultaneously burning the first and second air-fuel mixtures, and a rectification path (introduction section) provided in the first and second burners for supplying fuel gas together with air. 4a, 4b to flame hole 3
The length of the first burner side is longer than that of the second burner side (paths leading to a and 3b), and the agitation of fuel gas and air is improved.

According to a first aspect of the present invention, there is provided a combustion apparatus for burning a first fuel-lean mixture, and a second burner for burning a second fuel-rich mixture. And a burner (burner unit 1b) for simultaneously burning the first and second air-fuel mixtures, wherein the rectifier supplies fuel gas to the first burner and the second burner together with air. Route (introduction section 4a, 4b
Individually path) extending burner port portion 3a, and 3b from provided, the
The first burner connects the rectification path to the second burner.
It is formed longer than the rectification path and has a burner body.
A mixing pipe which forms a part of the rectification path below (2a)
(5a), a stenosis portion dividing the rectification path into a middle portion
(9), a narrowed portion (8a) with a narrowed passage, divided into a plurality at the top
It is characterized by having a flame hole (3a) formed and formed .

That is, the first and second burners are supplied with the first or second air-fuel mixture through rectification paths provided separately, but the first burner side has a fuel-lean mixture with a large amount of fuel gas. The first air-fuel mixture is supplied. Therefore, by setting the rectification path on the first burner side longer than the rectification path on the second burner side, the agitation between the fuel gas and the air is enhanced. Such a mixture having a high stirring property contributes to complete combustion.

The combustion of the first fuel-lean mixture in the first burner and the second fuel-rich mixture in the second burner are simultaneously burned, so that complete combustion is achieved and nitrogen oxides and Generation of noise can be suppressed.

That is, since the fuel-lean mixture is excess air, it alone lacks flame stability. In contrast, a fuel-rich mixture provides a stable combustion state. The flame in such a stable combustion state acts as a seed for combustion of a fuel-lean mixture, that is, a flame holding action, and can stabilize the flame of excess air. As described above, since the first and second air-fuel mixtures are simultaneously burned by the first and second burners, the lift of the flame and the oscillating combustion are prevented, and the generation of noise can be suppressed.

Since the combustion of the fuel-lean mixture is the combustion of excess air, the temperature of the flame is maintained at a low temperature by the cooling action of the excess air, and as a result, the generation of NOx is reduced.

[0011]

Further, in the first burner-side first mixture thin high fuel having the fuel gas amount is supplied. Then, this mixture is supplied to the mixing pipe, and flows and is stirred. However, after the mixture is divided into a plurality of flows by the constriction portion which is set in the middle thereof and divides the rectification path, the mixture is throttled. Then, it is in a pressurized state through the portion, and then reaches a flame hole portion divided and formed. In such a form, through a long rectification path, the agitation of the air-fuel mixture is enhanced, and contributes to complete combustion.

According to a second aspect of the present invention, the commutation path of the first burner is set to be long by making the heights of the first burner and the second burner different. It is characterized by having done. That is, a necessary rectification path is formed by changing the height.

The combustion apparatus according to a third aspect of the present invention is configured such that the fuel gas amount contained in the first air-fuel mixture is reduced by the second air-fuel ratio.
Is set to be larger than the amount of fuel gas contained in the air-fuel mixture. By setting such a fuel gas amount, a large amount of fuel gas can be diluted and burned, the combustion can be stabilized, and the generation amount of NOx can be suppressed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in the drawings.

1 to 4 show an embodiment of a combustion apparatus according to the present invention. This burner includes a burner unit 1 shown in FIG. 1 as a first burner for burning a first air-fuel mixture.
a and a burner unit 1b shown in FIG. 4 as a second burner for burning the second air-fuel mixture. First and second
Is a mixture of fuel gas and air, the first mixture is fuel-lean, the second mixture is fuel-rich, and the first mixture is fueled by the second mixture. A large amount of gas is set. And these burner units 1a,
1b is a vertical flat burner body 2a, 2b, respectively.
A mixing pipe having a flame hole 3a, 3b in the upper part and fuel gas and air introduction parts 4a, 4b on the lateral side of the lower part, and forming a rectification path from each introduction part 4a, 4b to the flame hole 3a, 3b. Part 5a,
5b. The burner unit 1a is formed such that the vertical width of the burner body 2a is wider than the vertical width of the burner body 2b of the burner unit 1b, and the distance from the introduction part 4a to the flame hole part 3a, that is, the straightening path, is determined. Unit 1
It is set longer than that of b. In this embodiment,
By making the heights of the burner units 1a and 1b different, the length of the rectification path on the burner unit 1a side is increased. In the burner unit 1b, a flame holding flame 19c is formed in the sleeve fire forming plate 10 as shown in FIG. As shown, the burner unit 1b includes:
Ignition device 20 provided with high-pressure cord 21 as ignition means
And a detection device 22 having a detection code 23 is provided.

The burner bodies 2a and 2b of each burner unit 1a and 1b are composed of a thin upper part u and a thick lower part d.
Are formed at the upper end of the upper portion u.
b, and the introduction portions 4a and 4b and the mixing tube portions 5a and 5b are formed in the lower portion d. The flame holes 3a, 3b are formed as a plurality of short slit-shaped openings arranged in a line by narrowing the long slit-shaped openings 6a, 6b at the upper end of the upper portion u at predetermined intervals. The flame hole portions 3a and 3b may employ an appropriate configuration such as a configuration in which a number of transverse slits are arranged.

The introduction portions 4a and 4b are formed as openings that open at one end of the lower portion d, and throat portions 7a and 7b are formed inside the openings. Then, the mixing pipe section 5 that extends from the throat sections 7a and 7b to the other end of the lower section d and returns to the lower end of the upper section u
a and 5b are configured. Also, the burner unit 1a
The inlet 4a and the mixing pipe 5a have larger diameters than those of the burner unit 1b, so that a larger amount of fuel gas and air can be introduced.

Each of the burner units 1a and 1b has an upper portion u formed with narrow portions 8a and 8b crossing the upper portion u. The burner unit 1a is located upstream of the narrow portion 8a at predetermined intervals. The constriction 9 is formed to form a rectification path. As shown in FIG. 7, a sleeve fire forming plate 10 is provided outside the upper portion u of the burner unit 1b. (Not shown) is provided. These are merely examples, and each component can be appropriately configured.

Next, FIGS. 5 to 8 show burner units 1a,
1b shows a burner as a combustion device configured with 1b. FIG. 5 is an overall plan view partially omitted, and FIG. 6 is an air chamber 11 and first and second nozzle holders 12a and 12a.
FIG. 7 is an enlarged front view of a main part showing a configuration and a combustion state by enlarging a main part of FIG.
FIG. 8 is a side view.

Each of the burner units 1a and 1b is supported by a support box 13 as a housing member in a state where the flame holes 3a and 3b are alternately arranged at the same height or with a slight difference in height. It is configured. In the embodiment, as shown in FIGS. 6 and 7, the height of the flame hole 3a of the burner unit 1a is
The height is set slightly lower than the height of the flame hole portion 3b of the burner unit 1b, and is set substantially equal to the upper end of the sleeve fire forming plate 10. As is clear from FIGS. 5 and 6, burner units 1b are provided at both ends of the burner unit 1a.

As described above, the burner unit 1a is configured such that the vertical width of the burner body 2a is wider than the vertical width of the burner body 2b of the burner unit 1b, as shown in FIGS. 6, 7 and 8. The introduction portions 4a of the burner unit 1a are arranged side by side in a row below the introduction portion 4b of the burner unit 1b. And the introduction part 4b of the burner unit 1b is arranged in a horizontal line between the upper part u of the burner body 2a of the burner unit 1a, and the burner unit 1a
Despite having a large-diameter inlet section 4a and a mixing pipe section 5a, the space between the adjacent upper portions u of the burner units 1a and 1b is reduced. Therefore, the burner units 1a and 1b can be mounted at a high density.

The support box 13 includes burner units 1a, 1
b, upper and lower nozzle holders 12a and 12b corresponding to the upper and lower rows of the respective introduction portions 4a and 4b, that is, a lower nozzle holder 12a corresponding to the burner unit 1a;
Upper nozzle holder 1 corresponding to burner unit 1b
2b is installed. These nozzle holders 12
a and 12b are installed in an air chamber 11 having an open front side, and air is supplied into the air chamber 11 from a fan 14 as air supply means.

Then, these nozzle holders 12a, 1
Nozzles 15a and 15b are provided in 2b as means for ejecting and supplying the fuel gas corresponding to the respective introduction portions 4a and 4b. The diameters and positions of these nozzles 15a and 15b and the opening diameters of the introduction portions 4a and 4b satisfy the following conditions. A first air-fuel mixture which is fuel-lean and has a larger amount of fuel gas than the amount supplied to the burner unit 1b is supplied to the flame hole 3a, and a second air-fuel mixture rich in fuel is supplied to the flame hole 3b. For example, the air ratio of the air-fuel mixture supplied to the flame holes 3a, 3b of the burner units 1a, 1b is calculated based on the theoretical air amount λ =
If it is set to 1, it can be set so that λ ≒ 1.2 to 1.5 and λ ≒ 0.4, respectively. The ratio of the amount of fuel gas supplied to each of the flame holes 3a and 3b is, for example, the fuel gas amount on the side of the burner unit 1a: the burner unit 1
The fuel gas amount on the b side can be set to be about 8: 2 to 6: 4. This is an example, and the air ratio and the fuel gas amount ratio are not limited to these ranges, but can be set appropriately beyond these ranges.

Next, FIG. 9 shows a state related to the nozzle holder as viewed from the back side of the nozzle, and FIG. 10 shows a state viewed from the side surface side. Each of the nozzle holders 12a and 12b is divided into three parts l, r, and m at the left and right and at the middle by partitioning plates 16a and 16b. Supply pipes 18l, 18r, and 18m are provided. Further, as is clear from the arrangement of the nozzles 15a and 15b, burner units 1b are installed at both ends of a burner in which a number of burner units 1a and 1b are arranged in a row. The burner units 1b corresponding to the nozzles 15b at both ends of the intermediate portion m of the nozzle holder 12b are adjacent to the outside of the burner units 1a corresponding to the nozzles 15a at both ends of the intermediate portion m of the nozzle holder 12a.

In the burner thus configured, fuel gas is supplied to all fuel gas supply pipes 18l, 18r, 18m. Fuel gas is supplied to the nozzle holders 12a and 12b through the communication pipes 17l, 17r and 17m, and air is supplied from the fans 14a and 14b into the air chamber 11 to perform combustion.

The fuel gas supplied to the nozzle holders 12a, 12b is jetted from the respective nozzles 15a, 15b in the direction of the introduction portions 4a, 4b of the corresponding burner units 1a, 1b, and the surrounding air is released by the jet energy. It is introduced into the burner bodies 2a, 2b while sucking. While the fuel gas and the air introduced into the burner bodies 2a and 2b from the introduction sections 4a and 4b are mixed, the mixing pipe section 5a,
5b to the respective flame holes 3a and 3b, from which they are ejected as an air-fuel mixture for combustion. At this time, a fuel-lean mixture is blown out from the burner portion 3a of the burner unit 1a, and a fuel-rich mixture is blown out from the burner portion 3b of the burner unit 1a. The amount of fuel gas contained in the air-fuel mixture ejected from the burner unit 1b is larger than the amount of fuel gas contained in the air-fuel mixture ejected from the flame hole 3b of the burner unit 1b.

By the supply of the air-fuel mixture as described above, a flame (first flame 19a) formed by burning the fuel-lean air-fuel mixture is formed above the flame hole 3a of the burner unit 1a, and the burner unit 1b is formed. Above the flame hole 3b, a flame (second flame 19b) formed by combustion of the fuel-rich mixture is formed. At this time, since the burner unit 1b is located on both ends of the burner unit 1a, the flame 19b exists on both sides of the flame 19a.

The flame 19a is due to the combustion of a fuel-lean mixture and has poor stability alone, but the flames 19b located on both sides thereof are stable due to the combustion of a fuel-rich mixture. The flame 19b acts as a pilot flame, and the flame 19a is stabilized. In addition, flame 19b
The flame is held from its surroundings by the flame holding flame 19c, so that its stability can be further improved. Therefore, the lift of the flame 19a and the oscillating combustion hardly occur,
Generation of noise can be suppressed.

The flame 19b becomes extremely stable. The burner unit 1b that generates the flame 19b is ignited by the ignition device 20 and detected by the detection device 22.

Incidentally, the flame 19 caused by the lean combustion of the fuel is used.
The stability of a is also affected by the mixing state of the mixture,
If the mixing is not sufficiently uniform, the stability is poor. In this regard, in the combustion device of the present invention, the burner unit 1
The flow straightening path from the introduction part 4a to the flame hole part 3a is longer than that of the burner unit 1b. Therefore, since the distance of the rectifying path for mixing is long, the mixing of the fuel gas and the air becomes good, and even if the fuel is lean, a large amount of the air-fuel mixture evenly mixed can be supplied to the flame hole portion 3a. . For this reason, the combustion device of the present invention also provides the flame 19a in this respect.
Has good stability.

Since the combustion of the stabilized fuel-lean mixture is the combustion of excess air, the temperature of the flame 19a is maintained at a low temperature by the cooling action, and the generation of NOx is reduced. Further, since the amount of fuel gas supplied to the combustion as a fuel-lean mixture is larger than the amount of fuel gas supplied to the fuel-rich mixture, NOx relative to the combustion amount of the entire burner is increased. The amount of generation is also small.

Next, in the above combustion state, the supply of the fuel gas from the fuel gas supply pipe 18r on the right side in FIG. 9 is stopped, and the supply of the fuel gas to the right side r of the nozzle holders 12a and 12b. Is stopped, the burner units 1a and 1b corresponding to the nozzles 15a and 15b in this portion are extinguished, and the burner units 1a and 1b corresponding to the nozzles 15a and 15b in the middle portion m of the nozzle holders 12a and 12b and the left portion l. Only combustion continues.

Since the burner units 1b are located at both ends of the burning burner units 1a and 1b,
Similar to the above-described combustion state, the flame 19b always exists on both sides of the flame 19a.
The stabilizing action of 9a is not inhibited.

Next, in the above combustion state, when the supply of the fuel gas from the intermediate fuel gas supply pipe 18m is also stopped, the burner units 1a and 1b corresponding to the left portion l of the nozzle holders 12a and 12b are selected. To continue burning. Even in this combustion state, since the flame 19b always exists on both sides of the flame 19a, the stabilization of the flame 19a by the flame 19b is not hindered.

In the above embodiment, the flame hole area to be burned can be changed stepwise without obstructing the stabilizing action of the flame 19a by the flame 19b, and the known combustion amount control such as proportional control can be performed. By using them together, the combustion amount can be adjusted over a wide range.

Next, FIG. 11 shows an example of the NOx emission characteristics in the combustion apparatus of the present invention. In the combustion device of the present invention, the air ratio of the fuel-rich mixture in the burner unit 1b is set to λ = 0.4 to 0.7, and the air ratio of the burner as a whole is the value shown on the horizontal axis in the figure. In this manner, the amount of generated NOx when the air ratio of the fuel-lean mixture in the burner unit 1a is adjusted and combusted is shown. The indicated air ratio is a value including the cooling air when the cooling air flows around the burner units 1a and 1b, and the air ratio in parentheses is a value not including the cooling air. It is. The ratio between the amount of fuel gas burned in the burner unit 1a and the amount of fuel gas burned in the burner unit 1b is:
7.5: 2.5. As shown in FIG. 11, in the combustion device of the present invention, it can be seen that the generation amount of NOx is significantly reduced as compared with the conventional general Bunsen burner.

FIG. 12 shows an example of the lift limit of the flame 19a by the burner unit 1a in the combustion apparatus according to the present invention, in comparison with the others. A is
In the combustion apparatus of the present invention, the lift limit of the burner unit 1a is shown when the fuel-lean mixture is supplied only to the burner unit 1a and the flame holding by the flame 19b of the burner unit 1b is not performed. =
It is about 0.7. On the other hand, B indicates a lift limit in a conventional general Bunsen burner having a flame holding mechanism, and this limit is about λ = 1.3. C indicates the lift limit of the burner unit 1a when the burner units 1a and 1b are burned in the combustion apparatus of the present invention, and λ is about 3.0. As described above, in the combustion device of the present invention, compared with a conventional general Bunsen burner, combustion of excess air can be performed more stably, NOx can be reduced by combustion of excess air, and fuel richness can be achieved. It can be seen that the flame holding of the fuel-lean mixture is performed by the combustion of the rich mixture, and a stable combustion state is realized.

[0039]

As described above, according to the present invention, the following effects can be obtained. a. Since the fuel-lean mixture and the fuel-rich mixture are burned simultaneously, complete combustion can be obtained,
Combustion can be stabilized, the generation of nitrogen oxides can be suppressed, and noise can be reduced. Thus, a small-sized combustion device having a large combustion amount can be provided. b. In the combustion of a fuel-lean mixture, the ratio of the amount of fuel gas supplied to the combustion of excess air is large, and the amount of NOx generated relative to the combustion amount of the entire combustion apparatus can be suppressed. c. Since the fuel-lean mixture and the fuel-rich mixture are combusted simultaneously, the combustion of the fuel-lean mixture can be stabilized without causing a flame lift or oscillating combustion, and noise can also be suppressed. . d. A first burner is formed by forming a mixing pipe which forms a part of a rectification path below the burner body, a constriction which divides the rectification path in the middle, a constricted part where the path is narrowed, and a plurality of sections formed in an upper part. Since the flame hole portion is provided, a sufficient length can be provided for the rectification path, and the stirring performance between the fuel gas and the air can be increased, thereby contributing to complete combustion. According to the second aspect of the present invention, since the height of the first burner and the height of the second burner are made different and the rectification path on the first burner side is set to be long, the rectification path can be lengthened. It can be facilitated. According to the third aspect of the present invention, since the amount of fuel gas contained in the first mixture is set to be larger than the amount of fuel gas contained in the second mixture, a large amount of fuel gas is diluted. Combustion and stabilization of combustion, NOx
Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first burner which is an embodiment of a combustion device of the present invention.

FIG. 2 is a sectional view of the combustion device shown in FIG. 1 taken along line XX.

FIG. 3 is a sectional view taken along line YY of the combustion apparatus shown in FIG.

FIG. 4 is a perspective view showing a second burner which is an embodiment of the combustion device of the present invention.

FIG. 5 is a plan view showing a combustion apparatus according to an embodiment of the present invention with a part thereof omitted;

FIG. 6 is a partially cutaway front view of a combustion device according to an embodiment of the present invention.

FIG. 7 is an enlarged front view showing a main part of a part of the combustion device of FIG. 6;

FIG. 8 is a side view showing a configuration of an embodiment of the combustion apparatus of the present invention.

FIG. 9 is a view showing the back side of the nozzle of the nozzle holder in the combustion apparatus of the present invention.

FIG. 10 is a side view of the nozzle holder shown in FIG.

FIG. 11 is a diagram showing a comparison of NOx generation amounts between the combustion device of the present invention and a conventional Bunsen burner.

FIG. 12 is a diagram illustrating a flame lift limit of a burner unit.

[Explanation of symbols]

 1a Burner unit (first burner) 1b Burner unit (second burner) 2a Burner body 3a, 3b Flame hole 4a, 4b Introducing section 5a Mixing pipe section 8a Narrow section 9 Narrow section

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kimio Mochizuki 201 Nishi-Kashiwara Nitta, Fuji City, Shizuoka Prefecture Inside Takagi Sangyo Co., Ltd. (56) References JP-A-3-263503 (JP, A) JP-A-1-219406 (JP, A) JP-A-61-165319 (JP, A) JP-A-2-36716 (JP, U) Hira 2-115627 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F23D 14/02-14/08 F23C 11/00 329-330

Claims (3)

(57) [Claims] A first burner configured to burn a first fuel-lean mixture; and a second burner configured to burn a second fuel-rich mixture. A combustion device for simultaneously burning air , wherein a rectification path for supplying fuel gas to the first burner and the second burner together with air is provided separately,
The burner connects the straightening path to the second burner.
It is formed longer than the flow path and below the burner body.
Part is a mixing conduit that forms part of the rectification path, and
A constricted part that divides the rectification path, a constricted part that narrows the passage, and the upper part
A combustion device comprising a plurality of flame holes formed in a plurality of sections . 2. The combustion according to claim 1, wherein the rectifying path of the first burner is set to be long by making the heights of the first burner and the second burner different. apparatus. 3. The combustion apparatus according to claim 1, wherein the amount of fuel gas contained in the first mixture is set to be larger than the amount of fuel gas contained in the second mixture.