JP2003139304A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce NOx and size in a low NOx combustion device. SOLUTION: The combustion device is provided with a lean burner port 102 ejecting a lean mixture, a first rich burner port 106 provided adjacently to the lean burner port 102 and ejecting a first rich mixture, and a second rich burner port 109 provided adjacently to the first rich burner port 106 and ejecting a second rich mixture with lower mixture concentration than the first rich burner port 106. The first rich mixture fed from the first burner port 106 is cracked by stable flame of the second burner port 109, generated activation chemical species are fed to a base part of lean flame by diffusion and a high temperature and high reaction area livelily carrying out combustion reaction is formed, and by this, stabilized ultralow NOx and miniaturization are realized even when a high speed lean mixture is fed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion apparatus mainly for household or business use, which has an extremely low NOx and at the same time has a small size.

[0002]

2. Description of the Related Art A conventional low NOx combustion device of this type is generally shown in FIG. 12 of JP-A-6-82011. In this low NOx combustion device, a lean burner 2 for ejecting a lean air-fuel mixture from a lean flame port 1 into the combustion chamber and a rich burner 4 for injecting a rich air-fuel mixture from both sides of the lean burner 2 alternately. Is configured to be placed.

The lean lean air-fuel mixture supplied from the lean burner 2 has a low flame temperature in the combustion chamber and therefore low NOx.
However, he himself forms an unstable lean flame. On the other hand, the rich mixture supplied from the rich burner 4 has a high flame temperature in the combustion chamber and therefore a high NOx concentration, but forms a stable rich flame by itself, and supplies thermal energy to the adjacent lean flame to accelerate the combustion reaction. By doing so, stable so-called light and dark combustion is realized as a whole. Then, the fuel supply ratio of the light burner 2 is set to be larger than that of the rich burner 4, and low NOx as a whole is obtained.
I was trying to make it.

As another example, Japanese Patent Laid-Open Publication No. 7-310906 discloses a rich / lean combustion type combustion device in which the concentration of air-fuel mixture is similarly changed stepwise to reduce NOx. As shown in FIG. 13, this device is arranged in a rich air-fuel mixture chamber 9 from a lean air-fuel mixture chamber (not shown) to a section 12 of a lean air-fuel mixture passage 11 that connects to a lean flame port 10 and is subjected to rich mixing. The air injection port 13 is provided.

Then, the rich air-fuel mixture is supplied from the rich air-fuel mixture chamber 9 to the lean air-fuel mixture passage 11 of the partition 12 which is divided by the partition through the rich air-fuel mixture injection port 13, and the rich air-fuel mixture is supplied to both ends of the lean flame port 10 at an intermediate position. Forming a concentrated intermediate flame A and a low velocity lean flame B,
The lean flame C, which is the main flame, is stabilized together with the action of the rich flame D to reduce the NOx.

[0006]

However, in the low NOx combustion device in the first conventional example, the light burner 2 is used.
If an attempt is made to further reduce the NOx by increasing the fuel supply ratio of, the air flow rate is also increased to maintain the concentration of the lean air-fuel mixture, and the jet flow velocity of the lean air-fuel mixture ejected from the lean flame port 1 is increased. It will be greatly increased. However, the fuel supply ratio of the rich burner 4 is reduced accordingly, and since the lean flame is stabilized by the thermal energy of the rich flame, the lean flame with the increased jet velocity becomes very unstable and the low N
There is a problem that there is a limit to Ox conversion.

Also, the low NOx in the above-mentioned second conventional example.
In the combustion device, the mixture concentration in the section 12 divided by the partition becomes an intermediate concentration by mixing the rich mixture and the lean mixture, and the intermediate flame A formed is close to the theoretical mixture ratio at which the combustion speed becomes the highest. It becomes the concentration. On the other hand, the air-fuel mixture having an intermediate concentration of the intermediate flame A has the smallest jet flow velocity from the flame port. Therefore, the intermediate flame heats the flame mouth in the vicinity of the flame mouth, and causes red heat of the flame mouth or back which advances the flame toward the upstream side. Similarly, the intermediate flame B having a low flow velocity is also close to the flame mouth and red-heats the flame mouth, which makes it difficult to increase the variable range of the combustion amount. Further, in the flame base portion that determines the stability of the lean flame C that is the main flame, the lean flame B having a low flow velocity forms a substantial flame base portion, and the flame holding effect is small because the flame temperature is not high. Become. Therefore, also in this point, the variable adjustment range of the combustion amount becomes small, and there is a limit to further increase the combustion ratio of the lean flame to further reduce NOx and downsize.

As described above, in the conventional combustion device, the NO level is further reduced.
If the fuel supply ratio of the lean flame is increased in order to achieve x, the jet velocity of the lean air-fuel mixture increases, while the rich flame that holds the flame by the thermal effect decreases, and toward the flame mouth in the center part. It is a method in which the concentration of the air-fuel mixture gradually changes monotonically and becomes thinner, and it is restricted by the stability of the lean flame, and the injection of the lean air-fuel mixture is aimed at further reducing NOx and downsizing. There was a limit to increase the flow velocity and further decrease the concentration.

[0009]

Means for Solving the Problems In order to solve the above problems, the present invention provides a lean flame port for ejecting a lean air-fuel mixture, a first rich flame port for ejecting a first rich air-fuel mixture having a concentration higher than that, A second rich flame outlet for ejecting an air-fuel mixture having a concentration between the lean air-fuel mixture and the first rich air-fuel mixture is provided, and the respective flame orifices are arranged close to each other and the first rich flame orifice is provided next to the lean flame orifice. It is located.

As a result of detailed investigation of the flame base structure which determines the stability of the lean flame, which is a solution point of the technical problem, the following has been clarified by the above configuration. In other words, the rich air-fuel mixture supplied from the second rich-flame port is thinner than the first rich-flame port to form a stable flame, and promotes the thermal decomposition reaction of the rich air-fuel mixture ejected from the first rich-flame port. . Then, the rich air-fuel mixture supplied from the first rich flame port generates a large amount of chemically active intermediate products due to this thermal decomposition,
This intermediate product is diffused and supplied to the base of the lean flame formed on the lean flame mouth, and a "high temperature / high reaction zone" is formed in which the combustion reaction is actively carried out in the micro space of the base, whereby the lean flame itself is formed. It turned out to be stabilized. And as inferred from Hooke's law, which is the basis of material diffusion,
The higher the concentration difference of the air-fuel mixture ejected from the lean flame port and the first rich flame port, and the smaller the distance between the lean flame port and the first rich flame port, the more easily the "high temperature / high reaction zone" can be formed. found. Therefore, the jet velocity of the lean air-fuel mixture can be increased and the concentration of the lean air-fuel mixture can be reduced, so that NOx can be further reduced and downsized, and the combustion amount variable range and the high-speed air fluctuation can be increased. Can be followed to achieve stable combustion. Such a combustion system that supplies ultra-low NOx combustion by supplying air-fuel mixtures having different concentrations to each other is hereinafter referred to as "multi-concentration combustion" in order to distinguish it from conventional concentration combustion.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is directed to a lean flame port for jetting a lean air-fuel mixture, a first rich flame port for jetting a first rich air-fuel mixture having a concentration higher than that, and the lean air-fuel mixture. And a second rich flame outlet for ejecting a mixture having a concentration between the first rich mixture and each of the flame orifices is arranged close to each other and the first rich flame orifice is located next to the lean flame orifice, The distance between the lean flame and the first rich flame is set to 0.2 mm or more and 1 mm or less.

At the base of the lean flame, a "high temperature / high reaction zone" in which the combustion reaction is actively carried out is formed, whereby the lean flame itself is stabilized. Therefore, it is possible to increase the jet velocity of the lean air-fuel mixture and to reduce the concentration of the lean air-fuel mixture, so that it is possible to achieve further reduction of NOx and downsizing, and to increase the combustion amount variable range and high-speed air fluctuations. Following this, stable combustion can be realized.

According to a second aspect of the present invention, there is provided a lean flame port for ejecting a lean air-fuel mixture, a first rich flame port for ejecting a first rich air-fuel mixture having a concentration higher than that, the lean air-fuel mixture and the first air-rich mixture. A configuration is provided in which a second rich flame outlet that ejects a mixture having a concentration between the air-fuel mixtures is arranged, and the respective flame orifices are arranged close to each other, and the lean flame orifice is sandwiched between the first rich flame orifice and the second rich flame orifice. The distance between the lean flame opening and the first rich flame opening is 0.2 mm or more and 1 mm or less.

Since the number of the first rich flame openings and the second rich flame openings can be minimized, the combustion device can be manufactured in a lightweight and inexpensive manner. In addition, premixed flames with different concentrations, that is, different natural vibration frequencies are formed asymmetrically on the left and right sides of the lean flame, which suppresses the propagation of vibration and produces a loud sound at a specific frequency. Is effective in suppressing.

According to a third aspect of the present invention, there is provided a lean flame port for jetting a lean air-fuel mixture, a first rich flame port for jetting a first rich air-fuel mixture having a concentration higher than this, the lean air-fuel mixture and the first air-rich mixture. A second rich flame port for ejecting a mixture having a concentration between the mixtures is provided, and the respective flame ports are arranged close to each other, and the lean mixture of the lean flame ports flows into the adjacent flame ports. The flame outlet next to the flame orifice is defined as the second rich flame outlet that injects a mixture having a concentration between the lean mixture and the first rich mixture, and the silent portion distance between the lean flame orifice and the second rich flame inlet is set. It is set to 0.2 mm or more and 1 mm or less.

Since the jet resistance of the lean flame port is set to be larger than that of the second rich flame port and the lean flame port and the second rich flame port are adjacent to each other, the lean air-fuel mixture flows into the adjacent flame port. become. Therefore, it is possible to adjust the flow of the lean air-fuel mixture into the mixing chamber of the second rich flame port by simply providing openings and adjusting the area and number of them, and it is possible to easily deal with various fuels and to manufacture the combustion device at low cost. .

According to a fourth aspect of the present invention, the lean flame port, the first rich flame port, and the second rich flame port each have an independent air-fuel mixture chamber and fuel / air inlet.

Then, the ratio of fuel supply to the lean air-fuel mixture, the first rich air-fuel mixture and the second rich air-fuel mixture is adjusted to adjust the stable combustion range, and when the kind of fuel to be supplied is different, the fuel is supplied. The optimum fuel distribution ratio and the concentration of each mixture can be reset most easily. Therefore, various fuels can be used in the same combustion device.

According to the fifth aspect of the present invention, the lean flame port, the first rich flame port, and the second rich flame port each have a mixture chamber, and the second rich mixture chamber of the second rich flame port communicates with each other. It is configured to communicate with the lean air-fuel mixture chamber of the lean flame port via the means to generate an air-fuel mixture having a concentration between the lean air-fuel mixture and the first rich air-fuel mixture.

Further, the entire combustion apparatus can be manufactured in a smaller size and at a lower cost than in the case where individual fuel supply systems are provided.

According to a sixth aspect of the present invention, there is provided a lean flame port for jetting a lean air-fuel mixture, a first rich flame port for jetting a first rich air-fuel mixture having a concentration higher than that, and the lean air-fuel mixture and the first rich air-fuel mixture. With a second rich flame port for ejecting a mixture of the concentration between the air, the lean flame port, the first rich flame port, an air supply section is provided in proximity to any of the second rich flame port, and The lean flame port, the first rich flame port, and the second rich flame port each have a mixture chamber, and the second rich mixture chamber of the second rich flame port mixes air from the air supply unit. It is configured to generate a mixture having a concentration between the lean mixture and the first rich mixture.

By adjusting the opening area of the air supply section, the concentration and the injection amount of the second rich air-fuel mixture can be adjusted independently of the lean air-fuel mixture, so that various fuels can be easily handled.

According to the seventh aspect of the present invention, the lean flame port is provided with the air-fuel mixture chamber and the fuel / air introduction port, and the first and second rich flame ports respectively communicate with the air-fuel mixture chamber and the respective air-fuel mixture chambers. There is one common fuel / air inlet.

As compared with the case where fuel and air are individually supplied to the first rich flame opening and the second rich flame opening, the structure is simple and downsizing is achieved, and the fuel supply system and introduction corresponding to these flame openings are introduced. Since the air supply system up to the mouth can be shared, the entire combustion device can be manufactured in a small size and at low cost.

According to an eighth aspect of the present invention, a lean flame port having a lean air-fuel mixture chamber upstream, a first rich flame port having a first rich air-fuel chamber adjacent to the lean flame port and upstream, A second rich flame opening adjacent to the one rich flame opening and having a second rich air-fuel mixture chamber upstream is provided, wherein the second rich air-fuel mixture chamber is communicated with the lean air-fuel mixture chamber through a communicating means to dilute the lean air-fuel mixture. And a second rich mixture having a concentration between the first rich mixture and the first rich mixture, and a lean fuel / air inlet is provided upstream of the lean mixture chamber, and One common fuel / air inlet that communicates with both the first and second rich mixture chambers is provided upstream, and the non-part distance between the lean flame port and the first rich flame port is 0.2 mm or more. It is set to 1 mm or less.

Further, since the fuel is independently supplied to the lean fuel / air inlet and the common fuel / air inlet, the fuel supply ratio to the lean air-fuel mixture and the rich air-fuel mixture is adjusted for stable combustion. When the range is adjusted or the type of fuel to be supplied is different, the optimum fuel distribution ratio and the concentration of each air-fuel mixture can be easily reset for that fuel.
Therefore, various fuels can be used in the same combustion device.

The ninth combustion apparatus includes a lean flame port forming member for forming a lean flame port at an upper portion and a lean fuel / air introducing port at a lower portion,
A first rich flame mouth forming body that is joined to the lean flame mouth forming body to form a first rich flame mouth, and a second rich flame mouth that is joined to the first rich flame mouth forming body and the first rich flame mouth forming body. There is provided a second rich flame port forming body forming a common fuel / air introducing port communicating with the first rich flame port and the second rich flame port.

Then, the lean flame mouth forming body serves to form the lean flame mouth and the first rich flame mouth, while the first rich flame mouth forming body serves to form the first rich flame mouth and the second rich flame mouth. Therefore, it is possible to minimize the materials such as sheet metal that make up the burner unit.
The entire combustion device is lightweight and can be manufactured at low cost. In addition, since each flame port can be placed very close to each other, the temperature gradient and concentration gradient between each mixture become steep, which promotes the formation of the "high temperature / high reaction zone" of the lean flame base, The whole can be made more stable.

According to the tenth aspect of the invention, the first rich air-fuel mixture ejected from the first rich flame port is an over-concentrated air-fuel mixture outside the flammability limit.

Then, the concentration gradient between the lean air-fuel mixture and the first rich air-fuel mixture is increased to promote the inflow of the first rich air-fuel mixture into the base portion of the lean flame to promote the formation of the "high temperature / high reaction zone". It is possible to strongly stabilize the lean flame.

In the eleventh aspect of the invention, the fuel supply amount to the lean flame port is set to be larger than the fuel supply amount to the first and second rich flame ports.

Then, the ratio of the lean flame with a small amount of NOx can be increased, and ultra low NOx can be realized in the entire combustion apparatus.

In the twelfth aspect of the present invention, the jet speed of the air-fuel mixture from the lean flame port is set to be higher than the jet speed of the air-fuel mixture from the first and second rich flame ports.

The first concentrated air-fuel mixture is entrained in the lean air-fuel mixture due to the entrainment effect associated with the high-speed jet, and the formation of the "high temperature / high reaction zone" can be promoted. Further, since the lean flame is stabilized even if the flow velocity of the lean air-fuel mixture is set high, the area of the lean flame port can be made small, and the entire combustion apparatus can be made compact and inexpensive.

In the thirteenth aspect of the present invention, the flame opening area of the lean flame opening is set to be larger than the flame opening areas of the first and second rich flame openings.

Further, the jet speed of the lean air-fuel mixture does not become extremely high, a stable lean flame is formed, the load of the fan for supplying the combustion air is reduced, and the noise can be suppressed.

According to a fourteenth aspect of the present invention, the fuel of each flame outlet is
Among the passage lengths from the air introduction port to each flame port, the passage length from the fuel / air introduction port of the lean flame port to the lean flame port is set to be the longest.

Then, a large amount of air supplied from the lean fuel / air inlet and most of the fuel are sufficiently mixed while passing through a long passage, and are rectified and the turbulence is attenuated and supplied to the lean flame port. Therefore, super NOx combustion and reduction of combustion noise can be realized.

According to the fifteenth aspect of the present invention, the opening area of the fuel / air introducing port of the lean flame port is set larger than that of the fuel / air introducing port of the first and second flame ports.

A large amount of combustion air is supplied to the lean flame port without receiving a large pressure loss, and a large amount of lean air-fuel mixture is generated to form an ultralow NOx lean flame. Further, the load of the fan that supplies the combustion air is reduced, and noise can be suppressed.

According to the sixteenth aspect of the present invention, the fuel / air introducing port of the lean flame port is located below the fuel / air introducing port of the first and second flame ports.

The combustion air supplied by the fan is guided to the lean flame port from the lean fuel / air inlet located on the upstream side without receiving a large pressure loss, so that the load of the fan is reduced and the noise is suppressed. can do.

According to the seventeenth aspect of the present invention, there is provided igniting means for igniting the air-fuel mixture ejected from the flame opening, and the igniting means discharges the air-fuel mixture from the first and second flame openings at a high pressure so as to cross the air-fuel mixture. .

Then, regardless of fluctuations in the excess air ratio due to fluctuations in the fuel supply amount, the concentration of the air-fuel mixture that is most likely to ignite occurs at any position in the formation part of the high-pressure discharge α, and the fuel is supplied to the lean flame port. Ignition can be reliably performed even if a large amount is set, and discharge of unburned substances such as HC during ignition can be suppressed.

According to an eighteenth aspect of the present invention, the combustion apparatus according to any one of the first to ninth aspects is configured as a burner unit, and a plurality of the burner units are arranged adjacent to each other. Then, by appropriately selecting the number of burner units, it is possible to provide a combustion device having a wide range of capabilities.

The invention described in claim 19 is,
The burner unit according to any one of 9 is configured as a burner unit, and the burner unit is configured by arranging first rich flame ports on both sides of the lean flame port and second rich flame ports on both sides thereof.

Combustion can be completed with a single burner unit, the number of burner units, the arrangement interval, etc. can be freely selected, and the degree of freedom in design can be increased.

[0048]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic overall sectional view showing a combustion apparatus according to Embodiment 1 of the present invention, FIG. 2 is a perspective view showing a state in which a burner unit of the combustion apparatus is disassembled, and FIG. 3 is the same. FIG. 4 is a perspective view of a burner unit of the combustion device, FIG. 4 is a sectional view of the burner unit of the combustion device taken along the line TT, FIG. 5 is an enlarged view of the vicinity of the ignition means of the combustion device, and FIG. 6 is a schematic view of the flame of the combustion device. FIG. 7 is a diagram showing a blow-off flow velocity of the combustion device, and FIG. 8 is a diagram showing a relationship between a lean fuel ratio and NOx at the time of natural gas combustion.

In FIGS. 1 to 8, the lean flame mouth former 10 is formed.
Reference numeral 1 indicates a lean flame port 102 on the upper side, lean fuel / air inlet port 103 on the lower side, and lean mixture chamber 104 upstream of the lean flame port 102.
Is formed. The first rich flame mouth forming body 105 is joined to both sides of the lean flame mouth forming body 101, and the first rich flame mouth 106 and the first rich air-fuel mixture chamber 107 upstream thereof are formed. The second rich flame mouth forming body 108 is joined to the outside of the first rich flame mouth forming body 105, and the second rich flame mouth 109 and the second rich air-fuel mixture chamber 11 upstream thereof.
Forming 0. Further, the second rich flame port forming body 108 is also joined to the lean flame port forming body 101, so that the communication chamber 111 communicating with the first rich mixture chamber 107 and the second rich mixture chamber 110 and the lean fuel / air introducing port. A common fuel / air inlet 112 is formed at the upper part of 103. The lean flame port forming body 101 is provided with a communication means 113 for communicating the lean air-fuel mixture chamber 104 and the second rich air-fuel mixture chamber 110. A burner unit 114 is configured by integrating the lean flame port forming body 101, the first rich flame port forming bodies 105 on both sides thereof, and the second rich flame port forming bodies 108 provided on both sides thereof. Note that, in FIG. 2, for simplification of the drawing, a state in which the first rich flame mouth forming body 105 and the second rich flame mouth forming body 108 are joined to one side of the lean flame mouth forming body 101 is shown.

A plurality of burner units 114 are housed in the burner case 115 and are connected to the combustion chamber 116. Further, on the upstream side of the burner case 115, an on-off valve 117 for shutting off the fuel supply, a fuel pipe 119 having a fuel adjusting means 118 provided on the downstream side thereof, and a fan 120 for supplying combustion air are provided. Here, a lean fuel pipe 121 and a rich fuel pipe 122 are branched and provided on the downstream side of the fuel pipe 119. As shown in FIG. 3, each burner unit 114 has a lean nozzle 123 corresponding to the lean fuel / air inlet 103 and two common fuel / air inlets 11.
Two rich nozzles 124 corresponding to No. 2 are used for the lean fuel pipe 121.
And the rich fuel pipe 122 are respectively branched. Further, an ignition means 125 is provided near the first rich flame outlet 106 and the second rich flame outlet 109 as shown in FIG.

Next, the operation and action will be described. The opening / closing valve 117 is opened, and the fuel adjusted to a predetermined supply amount by the fuel adjusting means 118 passes through the fuel pipe 119 and the lean fuel pipe 121.
To the rich fuel pipe 122. And the lean nozzle 12
3 and the rich nozzle 124, the lean fuel / air inlets 103 of the burner units 114 are adjusted to a predetermined distribution ratio.
It is injected and supplied to the common fuel / air inlet 112, respectively.

Further, the combustion air supplied from the fan 120 at a predetermined flow rate is supplied into the burner case 115, and a part thereof passes through the gaps between the burner units 114 to cool the inner surface of the burner case 115. While combustion chamber 1
It flows to 16. Most of the combustion air is supplied to the lean fuel / air inlet 103 and the common fuel / air inlet 112 of each burner unit 114. Ignition means 125
To the first rich flame outlet 106 and the second rich flame outlet 10
A high-pressure discharge α is formed downstream of 9 to ignite.

From the lean nozzle 123, most (about 8
(0%) fuel and a large amount of combustion air are supplied from the lean fuel / air inlet 103 to the lean air-fuel mixture chamber 104, and are sufficiently mixed while passing through a long flow path of the lean air-fuel mixture chamber 104. A uniform lean air-fuel mixture with little turbulence is rectified and uniformly supplied to the lean flame port 102. Dilute flame mouth 1
As shown in FIG. 6 (a), the lean air-fuel mixture jetted into the combustion chamber 116 at high speed has a low flame temperature and is extremely NO.
A lean flame E having a low x concentration is formed.

A small amount of fuel is used for each burner unit 114.
Each of them is supplied from the two rich nozzles 124 to the common fuel / air inlet 112 together with a small amount of combustion air. While passing a relatively short flow path, a small amount of fuel and a small amount of combustion air become a uniform first concentration rich mixture outside the flammability limit and reach the communication chamber 111, where the first rich mixture chamber is formed. 107 and the second rich mixture chamber 110. First rich mixture chamber 107
The first concentrated air-fuel mixture supplied to the combustion chamber 116 flows out from the first rich flame port 106 into the combustion chamber 116 at a low speed with the same concentration.

On the other hand, the first rich air-fuel mixture supplied to the second rich air-fuel mixture chamber 110 is diluted with a small amount of the lean air-fuel mixture flowing from the communicating means 113 to become the second rich air-fuel mixture having a concentration close to the theoretical mixing ratio. , Out of the second rich flame port 109 into the combustion chamber 116. The second rich air-fuel mixture, which is ejected from the second rich flame port 109 and is close to the theoretical mixture ratio, has a high flame temperature and forms a stable flame F which is very stable. The first rich air-fuel mixture from the first rich flame outlet 106 flows out at a low speed, is thermally decomposed under the influence of the high-temperature stable flame F, and produces a large amount of intermediate products. Then, this is diffused and supplied to the base portion of the lean flame F formed on the lean flame port 102, and a "high temperature / high reaction zone" β in which the reactive chemical species are abundant and the combustion reaction is extremely active is formed at the base portion of the lean flame E. It The rich flame G formed by receiving the oxygen supply from the lean flame E is connected to the lean flame E and the stable flame F to form an integral flame. As a result, even if the flow velocity of the lean air-fuel mixture ejected from the lean flame port 102 is set to be high, an active combustion reaction is maintained at the flame base, so that stable combustion can be maintained without being blown off.

As described above, in the multi-concentration combustion having these three kinds of air-fuel mixture concentrations, the lean flame I is stabilized by the thermal influence of the rich flame H by the conventional rich-lean combustion shown in FIG. 6 (b). Compared to the case, it is possible to significantly stabilize the lean flame. Here, as shown in FIG. 7, in the conventional rich-lean combustion, as the non-portion portion distance L between the lean flame port and the rich flame port becomes smaller, the rich flame H is thermally influenced and the blow-off flow velocity of the lean flame I increases. However, if it becomes too small, the blowoff flow velocity V of the lean flame I decreases. This is because the rich flame H is pulled by the lean air-fuel mixture due to the shearing force of the lean air-fuel mixture and is easily blown off.
As a result, the lean flame I is also easily blown off.

In the multi-concentration combustion of the present invention, the stable flame E is formed on the outside of the rich flame G, so that the non-portion distance L between the lean flame port 102 and the first rich flame port 106 becomes 1 mm or less. A "high temperature / high reaction zone" β is formed, the blow-off flow velocity V of the lean flame F rapidly increases, and V increases until L becomes about 0.2 mm. This is because as L becomes smaller due to the steeper concentration gradient between the lean mixture and the first rich mixture, the diffusion of the first rich mixture into the lean mixture becomes more active, resulting in a "high temperature / high reaction zone".
This is because the formation of β is promoted. When L is smaller than about 0.2 mm, the rich flame G and the lean flame F are destabilized due to the influence of the shearing force of the above-mentioned lean mixture, and V is reduced. Here, the non-portion portion distance L between the lean flame port 102 and the first rich flame port 106 is the thickness of the lean flame port forming body 101.
By setting the thickness of the lean flame port forming body 101 to 0.3 mm, L becomes 0.3 mm, V becomes the largest, and the lean flame F is most stabilized.

As shown in FIG. 8, when the supply ratio of the lean fuel increases, that is, when the ratio of the leaning flame with low NOx increases, the final NOx of the combustion device also decreases. The lean fuel is zero, that is, NOx is a high concentration of 130 ppm at the point P where Bunsen combustion is performed, but the lean fuel supply ratio is about 60.
60pp, which is less than half at the Q point of normal light and dark combustion
It can be reduced to about m. Since the lean flame itself is stabilized in the multi-concentration combustion of the present invention, a larger amount of lean mixture can be stably burned, and the NOx concentration can be realized at the R point of 30 ppm or less. Further, since the lean flame E can be stabilized even if the flow velocity of the lean air-fuel mixture is set high, the area of the lean flame port 102 can be reduced, and the entire combustion apparatus can be made small and inexpensive.

Further, in this embodiment, since the flow rate of the lean air-fuel mixture from the lean flame port 102 is set to be high, the lean air-fuel mixture chamber 1
The internal pressure of 04 is larger than that of the second rich mixture chamber 110 in which the mixture flow velocity from the second rich flame port 109 is small. Therefore, the lean air-fuel mixture flows into the second rich air-fuel mixture chamber 110 through the communication means 113 for connecting the lean air-fuel mixture chamber 104 and the second rich air-fuel mixture chamber 110, and the first rich air-fuel mixture supplied from the communication chamber 111 is supplied. Dilute. By thus providing the communication means 113, the entire combustion apparatus can be made smaller and less expensive than the case where individual fuel supply systems are provided.

In this embodiment, the common fuel / air inlet 1
Since 12 is configured to communicate with the first rich air-fuel mixture chamber 107 and the second rich air-fuel mixture chamber 110, when the air-fuel mixture is individually supplied to the first rich flame port 106 and the second rich flame port 109. In comparison, the burner structure is simple and downsized, and the fuel supply system of the rich fuel pipe 122 and the rich nozzle 124 and the air supply system up to the introduction port can be shared, and the entire combustion device can be made small and inexpensive. be able to.

Further, in this embodiment, the lean fuel / air inlet 1 is used.
03 and the common fuel / air introducing port 112 are configured to independently supply fuel from the lean nozzle 123 and the rich nozzle 124, respectively. This adjusts the fuel supply ratio to the lean mixture and rich mixture to adjust the stable combustion range, and when the type of fuel to be supplied is different, the optimum fuel distribution ratio for that fuel and the optimum mixture ratio of each mixture. The concentration can be easily reset. Therefore, various fuels can be used in the same combustion device.

Further, in this embodiment, the lean flame mouth forming member 101,
The burner unit 114 is configured by joining the first rich flame mouth forming body 105 and the second rich flame mouth forming body 108. That is, the lean flame port forming member 101 includes the lean flame port 102 and the first rich flame port 1.
06, while the first rich flame mouth forming body 105 also serves as forming the first rich flame mouth 106 and the second rich flame mouth 109.

As a result, it is possible to minimize the materials such as the metal plate forming the burner unit, and the entire combustion apparatus can be manufactured lightweight and at low cost. Further, the no-letter distance between the lean flame port 102 and the first rich flame port 106 and the no-portion distance between the first rich flame port 106 and the second rich flame port 109 are the lean flame port forming body 101 and the first rich flame port, respectively. Only the thickness of the flame mouth forming body 105,
Can be configured very close together. Therefore, since the temperature gradient becomes large, the first rich air-fuel mixture in the first rich flame port 106 is strongly affected by the high temperature flame F on the second rich flame port 109,
Thermal decomposition is accelerated. Also, since the concentration gradient becomes large, the amount of the first concentrated air-fuel mixture rich in chemically active species that is diffused and supplied to the lean air-fuel mixture increases, and the formation of the "high temperature / high reaction zone" β is promoted. The overall flame formed on 114 is more stable.

Further, in this embodiment, since the concentration of the first rich air-fuel mixture ejected from the first rich flame outlet 106 is the rich air-fuel mixture outside the flammability limit, the concentration gradient of the lean air-fuel mixture and the first rich air-fuel mixture is As a result, the first concentrated air-fuel mixture is allowed to flow into the base portion of the lean flame E to form a "high temperature / high reaction zone" β, and the lean flame E can be firmly stabilized.

Further, in this embodiment, the fuel supply amount to the lean flame port 102 is set to, for example, about 80% of the total supply amount, which is larger than the fuel supply amounts to the first rich flame port 106 and the second rich flame port 109. is doing. As a result, the proportion of the lean flame E with a small amount of NOx can be increased, and ultra low NOx can be realized in the entire combustion device.

The jet speed of the lean air-fuel mixture from the lean flame port 102 is set to be faster than the jet speed of the first rich air-fuel mixture from the first rich flame port 106. Therefore, the first concentrated air-fuel mixture is entrained in the lean air-fuel mixture due to the entrainment effect of the high-speed jet, and as a result, the formation of the "high temperature / high reaction zone" β can be promoted.

Further, in the present embodiment, the flame opening area of the lean flame opening 102 is set larger than the flame opening areas of the first rich flame opening 106 and the second rich flame opening 109. Therefore, the jet speed of the lean air-fuel mixture does not become extremely high, a stable lean flame E is formed, the load of the fan 120 is reduced, and noise can be suppressed.

Further, in the present embodiment, of the passage lengths from the fuel / air introduction port of each flame port to each flame port, the passage length from the lean fuel / air introduction port 103 to the lean flame port 102 is set to be the longest. There is. As a result, a large amount of air supplied from the lean fuel / air introduction port 103 and most of the fuel are sufficiently mixed while passing through the passage, and are subjected to rectification to be evenly diluted with the lean flame port 102.
Is supplied to. In this way, uniform supply to the lean flame port 102 and attenuation of flow turbulence are achieved, so super NOx combustion and combustion noise reduction can be realized.

In this embodiment, the lean fuel / air inlet 1 is used.
The opening area of 03 is set larger than the opening area of the common fuel / air introducing port 112. This allows the fan 120
The combustion air supplied from the burner case 115 to the burner case 115 is supplied to the lean flame port 102 in a large amount without receiving a large pressure loss, and a large amount of lean air-fuel mixture is generated to form the ultralow NOx lean flame E. You can Further, the load on the fan 120 is reduced, and noise can be suppressed.

Also, in this embodiment, the lean fuel / air inlet 1 is used.
03 is located below the common fuel / air inlet 112. This allows the fan 120 to be connected to the burner case 1.
The combustion air supplied to the inside of 15 does not receive a large pressure loss, and each lean fuel / air inlet 1 is located on the upstream side.
03 to the lean flame outlet 102, the fan 120
The load can be reduced and the noise can be suppressed.

Further, in this embodiment, an igniting means for igniting the air-fuel mixture ejected from the flame mouth is provided, and the igniting means is used for the first and second rich air-fuel mixture from the first rich flame mouth 106 and the second rich flame mouth 109. A high-voltage discharge α is formed so as to traverse. Since the high-pressure discharge α is formed in the first rich mixture having a high concentration and the second rich mixture having a stoichiometric ratio close to the theoretical mixture ratio, it is the most regardless of the variation of the air excess rate due to the variation of the fuel supply amount or the fan speed. Air-fuel mixture concentration that easily ignites (primary air excess ratio is 0.6 to 0.8
Degree) occurs at any position in the formation part of the high-voltage discharge α.
As a result, even if a large amount of fuel is supplied to the lean flame port 102 for ultra-low NOx, ignition can be reliably performed, and discharge of unburned substances such as HC during ignition can be suppressed.

Further, in this embodiment, the lean flame port 102, the first rich flame port 106 on the outer side thereof, and the second rich flame port 1 on the outer side thereof are further provided.
The burner unit 114 is constituted by 09, and a plurality of the burner units 114 are arranged adjacent to each other as shown in FIG. Therefore, by appropriately selecting the number of burner units 114, it is possible to provide a combustion device having a wide range of capabilities.

Further, in this embodiment, the burner unit 114 is constructed by disposing the first rich flame openings 106 on both sides of the lean flame opening 102 and the second rich flame openings 109 on both sides thereof. For this reason,
Combustion can be completed with a single burner unit 114, and the number of burner units, arrangement intervals, etc. can be freely selected, and the degree of freedom in design can be increased.

Each burner unit 114 has two common fuel / air inlets 11 for the first and second rich flame inlets, respectively.
2 and two corresponding thick nozzles 124 are shown, the common fuel / air introduction port 11 shared by each rich flame port is shown.
2 and the thick nozzle 124 may be provided. The point is the first rich flame mouth 1
The fuel supplied to 06 is independent of the lean nozzle 123 supplied to the lean flame port 102. Further, the communication means 113 has a structure in which a part of the lean flame port forming body 101 is projected outward from an opening provided in the first rich flame port forming body 105 in FIG. Has a structure in which a part of the first rich flame mouth forming member 105 is protruded inward so as to be brought into close contact with the lean flame mouth forming member 101, but either one may be protruded or a component having a different structure is used. You may.

(Second Embodiment) FIG. 9 is a schematic overall sectional view showing a combustion apparatus according to a second embodiment of the present invention. The present embodiment is different from the first embodiment in that the lean flame port 102 and the first rich flame port 10 are provided.
6, the second rich flame inlet 109 is independent of each of the lean mixture chamber 104, the first rich mixture chamber 107, and the second rich mixture chamber 11
0, and each of them has a lean fuel / air inlet 103, a first rich fuel / air inlet 201, and a second rich fuel / air inlet 202 which are independent of each other. The first rich flame mouth 106 and the second rich flame mouth 1 are arranged.
The lean burner 102 is sandwiched between the burner unit 203 and the burner unit 203.

A plurality of burner units 203 are closely arranged to form a combustion device. A lean fuel pipe 121, a first rich fuel pipe 204, and a second rich fuel pipe 205 are branched and provided on the downstream side of the fuel pipe 119. Each burner unit 203 has a lean fuel / air inlet 103.
Corresponding to the first rich fuel / air inlet 201, the second rich nozzle 206 corresponding to the second rich fuel / air inlet 202, and the second rich nozzle 207 corresponding to the second rich fuel / air inlet 202. 1st fuel pipe 204 and 2nd fuel pipe 20
5 are branched from each. Example 1
Those having the same reference numerals as those have the same configuration and will not be described.

Next, the operation and action will be described. The fuel is branched into the lean fuel pipe 121, the first rich fuel pipe 204 and the second rich fuel pipe 205 through the fuel pipe 119. Then, the lean nozzle 123, the first thick nozzle 206, and the second thick nozzle 2
After adjusting to a predetermined distribution ratio at 07, the fuel is injected and supplied to the lean fuel / air introduction port 103, the first rich fuel / air introduction port 201, and the second rich fuel / air introduction port 202 of each burner unit 203. .

The combustion air supplied from the fan 120 at a predetermined flow rate is supplied with the lean fuel / air introduction port 103, the first rich fuel / air introduction port 201, the second rich fuel / air of each burner unit 203. Each is supplied to the inlet 202. Most of the fuel (about 80%) from the lean nozzle 123 and a large amount of combustion air are lean fuel / air inlet 103.
Is supplied to the lean mixture chamber 104 from the
At 4, a uniform lean mixture is produced. In addition, a small amount of fuel is supplied from the first rich nozzle 206 to the first rich fuel / air inlet 201 together with a small amount of combustion air, and the first rich air-fuel mixture chamber 107 uniformly mixes the first rich air-fuel mixture outside the flammability limit. Is generated.

Further, a small amount of fuel from the second rich nozzle 207, which is about the same amount as the first rich nozzle 206, and combustion air slightly larger than the combustion air supplied to the first rich fuel / air inlet 201 are generated. It is supplied to the second rich fuel / air inlet 202, and the second rich air-fuel mixture chamber 110 produces a second rich air-fuel mixture having a concentration close to a uniform theoretical mixture ratio. The first rich air-fuel mixture, the lean air-fuel mixture, and the second rich air-fuel mixture are ejected from the first rich flame port 106, the lean flame port 102, and the second rich flame port 109, respectively, and the rich flame G and the lean flame are supplied to each burner unit 203. Flames are formed in the order of F and stable flame E. Here, the wall thickness of the formed body of the lean flame port 102 is 0.3 mm, and the lean flame port 102 and the first rich flame port 10
The silent portion distance L with the No. 6 is set to 0.3 mm.

Here, the stable flame E of the adjacent burner unit is added, and on the left side of the lean flame F, the stable flame E, the rich flame G, and the lean flame F are formed in this order on the right side, as in the first embodiment. A flame is formed in the order of a lean flame F, a stable flame E, and a rich flame G. The "high temperature / high reaction zone" described in the first embodiment is formed on the left side base portion of the lean flame F (not shown) formed in the order of the stable flame E, the rich flame G, and the lean flame F (not shown), and the lean flame F, stable On the right side of the lean flame F, which is formed in order of the flame E and the rich flame G, the "high temperature / high temperature
No high reaction zone is formed. For this reason, the stability of the lean flame F is inferior to that of the first embodiment, and NOx is slightly increased as a result, but the number of the first rich flame openings 106 and the second rich flame openings 109 can be halved, so Combustion device is lighter and cheaper to manufacture.

Further, a rich flame G and a stable flame E adjacent to both sides of the lean flame F are formed in an asymmetrical order. In this way, premixed flames having different concentrations, that is, different natural vibration frequencies are formed asymmetrically on the left and right sides of the lean flame F, so that vibration propagation is suppressed and a loud sound is generated at a specific frequency. It is effective in suppressing so-called oscillatory combustion.

Further, since the fuel / air introduction port and the fuel nozzle are independently arranged at each flame port, the fuel supply ratio to the lean mixture, the first rich mixture and the second rich mixture is adjusted. When the stable combustion range is adjusted, or when the type of fuel to be supplied is different, the fuel distribution ratio and the concentration of each air-fuel mixture that are optimal for that fuel can be reset most easily. Therefore, various fuels can be used in the same combustion device.

(Third Embodiment) FIG. 10 is a schematic overall sectional view showing a combustion apparatus according to a third embodiment of the present invention.

The present embodiment is different from the first embodiment in that the second rich flame port 109 is arranged next to the lean flame port 102, the first rich flame port 106 is arranged next to it, and the second rich mixing is performed. Air chamber 1
A burner unit 302 is configured by providing a communication port 301 for communicating the lean air-fuel mixture chamber 104 with each other. The first rich air-fuel mixture chamber 107 and the second rich air-fuel mixture chamber 110 communicate with the communication chamber 305 through the first rich communication port 303 and the second rich communication port 304, respectively. Leftmost burner unit 302
Does not have a corresponding lean nozzle 123. The same reference numerals as those in the first embodiment have the same configurations, and the description thereof will be omitted.

The operation and action will be described below. A large amount of air and most of the fuel are supplied to the lean fuel / air introduction port 103 of each burner unit 302. Lean mixture chamber 1
At 04, a lean air-fuel mixture that is uniformly mixed is generated. On the other hand, a small amount of air and a small amount of fuel are supplied to the common fuel / air introduction port 112 of each burner unit 302. Communication room 30
5, a uniform first rich mixture outside the flammability limit is generated and distributed to the first rich mixture chamber 107 and the second rich mixture chamber 110 through the first rich communication port 303 and the second rich communication port 304, respectively. It The first rich air-fuel mixture in the first rich air-fuel mixture chamber 107 is ejected from the first rich flame outlet 106 into the combustion chamber 116 with the same concentration. Most of the lean air-fuel mixture generated in the lean air-fuel mixture chamber 104 is ejected from the lean flame port 102 into the combustion chamber 116. The jetting resistance of the lean air-fuel mixture is set to be larger than the jetting resistance of the second rich air-fuel mixture at the second rich flame port 109 by adjusting the flame opening area. Therefore, the pressure of the lean air-fuel mixture chamber 104 becomes higher than that of the second rich air-fuel mixture chamber 110, and a small amount of the lean air-fuel mixture flows out from the lean air-fuel mixture chamber 104 to the second rich air-fuel mixture chamber 110.

That is, the first rich air-fuel mixture is diluted in the second rich air-fuel mixture chamber 110, and the second rich air-fuel mixture having a ratio close to the theoretical mixing ratio is generated and ejected from the second rich flame port 109 into the combustion chamber 116. Then, a lean flame F is attached to each burner unit 302.
Flames are formed in the order of stable flame E and rich flame G. There is no corresponding lean nozzle 123 at the lean flame port 102 of the leftmost burner unit 302, and only the lean flame port 102 has air.
Eject more. Then, the stable flame E and the rich flame G of the adjacent burner unit 302 are added, and the stable flame E, the rich flame G, and the lean flame F are formed in this order on the left side of the lean flame F, similarly to the first embodiment, while the right side is formed. A flame is formed in this order of a lean flame F, a stable flame E, and a rich flame G.

Here, the wall thickness of the formed body of each flame mouth is 0.3 mm. On the left side of the lean flame port 102, the lean flame port forming body 101 and the first rich flame port forming body 105 overlap with each other, and the silent portion distance between the lean flame port 102 and the first rich flame port 106 is 0.6 mm. Become. On the other hand, on the right side of the lean flame opening 102, the distance between the lean flame opening 102 and the second rich flame opening 109 is 0.3 mm. Therefore, the concentration gradient between the lean air-fuel mixture and the first and second rich air-fuel mixture ejected adjacent to the lean air-fuel mixture becomes smaller than that in the configuration of the first embodiment, and the "high temperature" at the base of the lean flame F is generated. The reaction in the "high reaction zone" is less active than in the "high temperature / high reaction zone" formed in the configuration of Example 1.

Therefore, the stability of the lean flame F is inferior to that of the first embodiment, and NOx is slightly increased as a result, but the lean air-fuel mixture chamber 104 and the second rich air-fuel mixture chamber 110 are connected to each other. Since it is possible to communicate with each other through the communication port 301 which is a simple opening, instead of the communication means 113 having the protruding shape as in Example 1, the combustion device can be manufactured at a lower cost than in Example 1.
Further, the flow rate of the lean air-fuel mixture into the second rich mixing chamber can be adjusted by adjusting the area and the number of the communication ports 301, so that various fuels can be easily handled.

As a structure in which the lean air-fuel mixture flows into the adjacent flame ports, a structure in which a part of the lean flame port forming body 101 is cut and raised to the side of the lean air-fuel mixture chamber 104 so as to open to the upstream side is also possible. The same effect as the communication port 301 can be obtained. In this case, the outflow amount of the lean air-fuel mixture can be increased by utilizing the dynamic pressure of the lean air-fuel mixture.

(Fourth Embodiment) FIG. 11 is a schematic overall sectional view showing a combustion apparatus according to a fourth embodiment of the present invention.

The present embodiment is different from the first embodiment in that the burner unit 402 is constructed by providing the air supply section 401 in the vicinity of the second rich flame port 109. The same reference numerals as those in the first embodiment have the same configurations, and the description thereof will be omitted.

Next, the operation and action will be described. The first rich air-fuel mixture outside the flammability limit generated in the communication chamber 111 flows into the first rich air-fuel mixture chamber 107 and the second rich air-fuel mixture chamber 110.
Part of the air supplied from the fan 120 is the air supply unit 40.
From 1 to the second rich air-fuel mixture chamber 110, the first rich air-fuel mixture is diluted and a second rich air-fuel mixture close to the theoretical mixture ratio is generated.
Lean flame port 102, first rich flame port 106, second rich flame port 109
A lean mixture, a first rich mixture, and a second rich mixture are ejected into the combustion chamber, and a lean flame F, a rich flame G, and a stable flame E, respectively.
Are formed (not shown).

Here, in the first and third embodiments, the first rich air-fuel mixture is diluted with the lean air-fuel mixture in the second rich air-fuel mixture chamber, but in this embodiment, the lean air-fuel mixture is adjusted by adjusting the opening area of the air supply portion. Since the concentration and injection amount of the second rich air-fuel mixture can be adjusted independently of the air, it is possible to easily deal with various fuels.

The arrangement order of the flame openings is as follows: (1) lean flame opening 102, first rich flame opening 106, second rich flame opening 109 (Example 1) (2) first rich flame opening 106, lean Flame port 102, second rich flame port 109 (Example 2) (3) The lean flame port 102, the second rich flame port 109, and the first rich flame port 106 (Example 3) have been described in each example.

The burner unit has a flame port configuration (1) arranging the first rich flame port 106 and the second rich flame port 109 on both sides of the lean flame port 102 (Example 1) (2) first rich flame Arranging the flame port 106 and the second rich flame port 109 on one side of the lean flame port 102 (Example 3) has been described in each example.

Further, as a method for producing the second rich mixture close to the theoretical mixture ratio, (1) a common fuel / air inlet 112 common to the first rich mixture chamber 107 and the second rich mixture chamber 110 is provided, The second rich air-fuel mixture chamber 110 and the lean air-fuel mixture chamber 104 are communicated with each other by the communication means 113 (communication port 301) to dilute the first rich air-fuel mixture to generate the second rich air-fuel mixture (Examples 1 and 3). (2) A common fuel / air inlet 112 common to the first rich air-fuel mixture chamber 107 and the second rich air-fuel mixture chamber 110 is provided, and air is supplied from the air supply unit 401 provided in the second rich air-fuel mixture chamber 110 to the first The second rich mixture is generated by diluting the first rich mixture (Example 4) (3) First rich fuel / air introduction corresponding to the first rich mixture chamber 107 and the second rich mixture chamber 110, respectively. In each example, the port 201 and the second rich fuel / air inlet 202 are provided independently (Example 2). And Akira.

Here, in addition to the description in Examples 1 to 4,
The arrangement order of the flame openings, the flame opening configuration of the burner unit, and the method of producing the second rich air-fuel mixture described above may be appropriately combined.

Although the concentration of the second rich mixture has been described as the concentration between the first rich mixture and the lean mixture, the concentration may be the same as that of the first rich mixture. In this case, the stability of the lean flame is poor and NOx is high as a result, but the structure can be simplified.

In each embodiment, the fuel is gas fuel such as city gas, but liquid fuel such as kerosene may be gasified and used.

[0101]

As described above, the combustion apparatus of the present invention promotes the thermal decomposition of the rich air-fuel mixture flowing out from the first rich flame mouth by the stable flame of the second rich flame mouth to generate a large amount of active chemical species. Then, it diffuses and supplies it to the base of the lean flame formed on the lean flame mouth to form a "high temperature / high reaction zone" and stabilizes the lean flame, so the fuel supply ratio of the lean mixture can be increased. Low NOx can be realized.

[Brief description of drawings]

FIG. 1 is a schematic overall sectional view showing a combustion apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a burner unit of the combustion device is disassembled.

FIG. 3 is a perspective view of a burner unit of the combustion device.

FIG. 4 is a sectional view of a burner unit of the same combustion apparatus taken along the TT plane.

FIG. 5 is an enlarged cross-sectional view of the vicinity of the ignition means of the combustion device.

FIG. 6 (a) is a schematic diagram of a flame of the combustion device. (B) Reference schematic diagram of flame of the same combustion device

FIG. 7 is a characteristic diagram showing a blow-off flow velocity of a lean flame of the combustion device.

FIG. 8: Ratio of lean fuel and NOx during combustion of natural gas
Characteristic diagram showing the relationship of

FIG. 9 is a schematic overall cross-sectional view showing a combustion device according to a second embodiment of the present invention.

FIG. 10 is a schematic overall cross-sectional view showing a combustion apparatus of Example 3 of the present invention.

FIG. 11 is a schematic overall cross-sectional view showing a combustion apparatus of Example 4 of the present invention.

FIG. 12 is a sectional view of a main part of a conventional combustion device.

FIG. 13 is a sectional view of a main part of another conventional combustion device.

[Explanation of symbols]

101 Dilute flame mouth former 102 Dilute flame mouth 103 Lean fuel / air inlet 104 lean mixture chamber 105 First rich flame former 106 First rich flame mouth 107 First rich mixture chamber 108 Second rich flame mouth former 109 Second rich flame mouth 110 Second rich mixture chamber 112 Common fuel / air inlet 113 Communication means 114 burner unit 125 ignition means 201 First concentrated fuel / air inlet 202 Second concentrated fuel / air inlet 203 burner unit 302 burner unit 401 Air supply unit 402 burner unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Tomita             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor hair group             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3K017 AA06 AB02 AB07 AC02 AD01                       CA06 CB01 CB08                 3K065 TA01 TD05 TH04

Claims (19)

[Claims] 1. A lean flame port for ejecting a lean air-fuel mixture, a first rich flame port for ejecting a first rich air-fuel mixture having a concentration higher than that, and a concentration between the lean air-fuel mixture and the first rich air-fuel mixture. Alternatively, it is provided with a second rich flame port that ejects a mixture having the same concentration as the first rich air mixture, and the respective flame ports are arranged close to each other and the first rich flame port is adjacent to the lean flame port. A combustion device which is positioned so that the distance between the lean flame and the first rich flame is 0.2 mm or more and 1 mm or less. 2. A lean flame port for ejecting a lean air-fuel mixture, a first rich flame port for ejecting a first rich air-fuel mixture having a concentration higher than that, and a concentration between the lean air-fuel mixture and the first rich air-fuel mixture. Alternatively, it is provided with a second rich flame outlet for ejecting a mixture of the same concentration as the first rich air mixture, and the respective flame orifices are arranged in proximity to each other and the first rich flame orifice and the second rich flame orifice. And a lean flame port sandwiched between the lean flame port and the first rich flame port, and the distance between the lean flame port and the first rich flame port is set to 0.2 mm or more and 1 mm or less. 3. A lean flame port ejecting a lean air-fuel mixture, a first rich flame port ejecting a first rich air-fuel mixture having a concentration higher than that, and a concentration between the lean air-fuel mixture and the first rich air-fuel mixture. A second rich flame outlet for ejecting the air-fuel mixture, the flame outlets are arranged close to each other, and the lean air-fuel mixture of the lean flame inlet is formed so as to flow into an adjacent flame outlet. A flame outlet next to the flame orifice is defined as a second rich flame orifice that ejects a mixture having a concentration between the lean air-fuel mixture and the first rich air-fuel mixture, and there is no mouth between the lean flame orifice and the second rich flame orifice. Combustion device with part distance set to 0.2 mm or more and 1 mm or less. 4. The lean flame mouth, the first rich flame mouth, and the second rich flame mouth are:
The combustion device according to claim 1, 2 or 3, which has an air-fuel mixture chamber and a fuel / air inlet which are independent of each other. 5. The lean flame mouth, the first rich flame mouth, and the second rich flame mouth are:
Each of them has an air-fuel mixture chamber, and the second rich air-fuel mixture chamber of the second rich flame port communicates with the lean air-fuel mixture chamber of the lean flame port through a communicating means to form a lean air-fuel mixture and a first rich air-fuel mixture. The combustion apparatus according to claim 1 or 2, which produces a mixture having a concentration of between. 6. An air supply unit is provided near any of the lean flame port, the first rich flame port, and the second rich flame port, and the lean flame port, the first rich flame port, and the second rich flame port. Each have a mixture chamber, and the second rich mixture chamber at the second rich flame inlet mixes air from the air supply unit to mix the concentration between the lean mixture and the first rich mixture. The combustion device according to claim 1 or 2, which generates air. 7. The lean flame port is provided with a mixture chamber and a fuel / air inlet port, and the first and second rich flame ports are respectively provided with a mixture chamber and one common fuel communicating with each mixture chamber. The combustion apparatus according to claim 1, 2 or 3, wherein an air inlet is provided. 8. A lean flame port having a lean mixture chamber upstream, a first rich flame port having a first rich mixture chamber upstream of the lean flame port, and adjacent to the first rich flame port. And a second rich flame outlet having a second rich air-fuel mixture chamber upstream, and the second rich air-fuel mixture chamber is communicated with the lean air-fuel mixture chamber through a communication means to form a lean air-fuel mixture and a first rich air-fuel mixture. A second rich air-fuel mixture having a concentration of between 1 and 2 is provided, a lean fuel / air inlet is provided upstream of the lean air-fuel mixture chamber, and the first and second rich air-fuel mixture is provided upstream of the first rich air-fuel mixture chamber. Combustion in which one common fuel / air inlet communicating with both the second rich air-fuel mixture chamber is provided, and the distance between the lean flame and the first rich flame is 0.2 mm or more and 1 mm or less apparatus. 9. A lean flame port forming body forming an upper lean flame port and a lower lean fuel / air introducing port, and a first rich flame forming a first rich flame port bonded to the lean flame port forming body. A common fuel / air introduction port that is connected to the first rich flame port and the second rich flame port while forming a second rich flame port by joining the flame port forming body and the first rich flame port forming body. The combustion apparatus according to claim 8, further comprising a second rich flame mouth forming body to be formed. 10. The combustion device according to claim 1, wherein the first rich air-fuel mixture ejected from the first rich flame port is an over-concentrated air-fuel mixture outside the flammability limit. 11. The combustion apparatus according to claim 1, wherein the fuel supply amount to the lean flame port is set to be larger than the fuel supply amount to the first and second rich flame ports. 12. The combustion apparatus according to claim 1, wherein the jet speed of the air-fuel mixture from the lean flame port is set higher than the jet speed of the air-fuel mixture from the first and second rich flame ports. 13. The combustion apparatus according to claim 1, wherein the flame opening area of the lean flame opening is set larger than the flame opening areas of the first and second rich flame openings. 14. The passage length from the fuel / air introduction port of each lean to each lean is set to be the longest among the passage lengths from the fuel / air introduction port of each lean to each lean. A combustion device according to any one of claims 1 to 9. 15. The combustion apparatus according to claim 1, wherein an opening area of the fuel / air introduction port of the lean flame port is set larger than that of the fuel / air introduction port of the first and second flame ports. 16. The fuel / air introduction port of the lean flame port is first,
The combustion device according to any one of claims 1 to 9, which is located below a fuel / air introduction port of the second flame port. 17. An ignition means for igniting an air-fuel mixture ejected from a flame opening, the ignition means performing a high-pressure discharge across the air-fuel mixture from the first and second flame openings. The combustion device according to item 1. 18. A combustion device comprising the combustion device according to claim 1 as a burner unit, and a plurality of the burner units arranged adjacent to each other. 19. The burner unit according to any one of claims 1, 3 to 9 is configured as a burner unit, and the burner unit has a first rich flame port and a second rich flame port on both sides of a lean flame port. Combustion device arranged and configured.