JPH087217Y2 - Gas burner - Google Patents

Description

[Detailed description of the device]

[0001]

This invention relates to a gas burner,
More specifically, it relates to a so-called low NO _x gas burner in which the NO _x (nitrogen oxide) concentration in exhaust gas is reduced.

[0002]

2. Description of the Related Art FIG. 15 is a sectional view showing an example of a conventional gas burner.

This gas burner is provided with combustion air 2 from the outside.
A gas nozzle 32 to which the fuel gas 4 is supplied from the outside is provided coaxially with the air cylinder 30 to which is supplied, and a flame holding plate 34 is provided around the tip of the gas nozzle 32. . A plurality of gas ejection ports 32a are provided at the tip of the gas nozzle 32, and a large number of small holes 34a are provided in the flame holding plate 34. Further, a ring-shaped air port 36 is formed between the outer peripheral portion of the flame holding plate 34 and the air cylinder 30. Illustration of the pilot burner and the like is omitted.

[0004]

In the gas burner described above, the fuel gas 4 is radially ejected from the gas ejection port 32a of the gas nozzle 32, but the combustion air 2 is ejected from the entire circumference thereof, so that the flame is exposed to the surface. It will be in the shape of.
In such a state, the combustibility of the ejected fuel gas 4 is good, so that the combustion efficiency is high, while the combustion temperature is high, so the NO _x concentration in the exhaust gas is high, which is one of the causes of environmental pollution. It is desired to reduce the NO _X concentration.

Therefore, the main object of the present invention is to provide a gas burner capable of reducing the NO _X concentration in exhaust gas.

[0006]

In order to achieve the above object, the first gas burner of the present invention comprises an air cylinder to which combustion air is supplied from the outside, and a flared end provided at the tip of the air cylinder. An air cone and a cylindrical gas nozzle provided coaxially with the air cylinder and supplied with fuel gas from the outside, wherein fuel gas is provided around the tip end portion of the fuel gas with respect to the central axis of the gas nozzle. A plurality of gas jets ejecting in a substantially right-angled direction at substantially equal intervals, a flame holding plate provided around the root side of the gas jet of the gas nozzle and having a number of small holes, and the gas nozzle. A guide plate that is provided substantially parallel to the flame holding plate on the tip end face of the gas nozzle and is larger than the outer diameter of the gas nozzle, and is formed between the flame holding plate and the air cone for combustion in the air cylinder. Jetting air That an air inlet is divided into the same number and the gas port in the circumferential direction of the gas nozzle,
In addition, the center of each air port is located approximately on the center line between the adjacent gas ejection ports.

A second gas burner according to the present invention is an air cylinder to which combustion air is supplied from the outside, and a cylinder shape provided coaxially with the air cylinder to supply fuel gas from the outside. A gas nozzle, which has a plurality of gas ejection ports for ejecting fuel gas along the central axis of the gas nozzle at substantially equal intervals around the tip end face portion, and is provided in the gas nozzle coaxially therewith. An inner cylinder to which combustion air is supplied from the outside, the tip of which protrudes from the gas nozzle, and the combustion air is directed around the tip in a direction substantially perpendicular to the central axis of the inner cylinder. A plurality of gas outlets of the gas nozzle and the same number of primary air openings as the gas outlets of the gas nozzle are arranged at substantially equal intervals, and the centers of the respective primary air openings are located substantially on the center line between adjacent gas outlets, Gas nozzle A flame holding plate which is provided around the tip and has a large number of small holes, and a guide plate which is provided on the tip end face of the inner cylinder substantially parallel to the flame holding plate and is larger than the outer diameter of the inner cylinder. And a secondary air port formed between the flame holding plate and the air cylinder for ejecting combustion air in the air cylinder, the number being equal to the number of the gas ejection ports in the circumferential direction of the gas nozzle. It is divided, and the center of each secondary air port is located approximately on the center line between adjacent gas ejection ports.

[0008]

In any of the above gas burners, the flame is radially divided and spreads to the outside so that the combustion temperature is appropriately lowered and the exhaust gas circulation flow is increased, resulting in NO in the exhaust gas. Experiments confirmed that the _X concentration decreased.

[0009]

1 is a sectional view showing a gas burner according to an embodiment of the present invention. FIG. 2 is a front view of the gas burner of FIG.

This gas burner is provided with a cylindrical air cylinder 8 to which the combustion air 2 is supplied from the outside via a wind box 6 in this example. An air cone 10 is provided at the tip of the air cylinder 8 so as to eject the combustion air 2 obliquely outward. The position of this air cone can be adjusted back and forth as indicated by arrow A according to the required amount of combustion and the like.

A cylindrical gas nozzle 12 to which the fuel gas 4 is supplied from the outside is provided in the air cylinder 8 coaxially therewith. Further, in this example, a pilot burner 22 is provided beside it. The gas nozzle 12 has a plurality of (five in this example) gas outlets 12a for ejecting the fuel gas 4 in a direction substantially perpendicular to the central axis of the gas nozzle 12 around the tip portion thereof at substantially equal intervals. It is provided.

A flame holding plate 14 is provided around the gas nozzle 12 at the base side of the gas nozzle 12 so as to penetrate the gas nozzle 12. This flame holding plate 1
4 is provided with a large number of small holes 14a for forming an appropriate mixture with the fuel gas 4 ejected from the gas ejection port 12a.

At the tip end face of the gas nozzle 12, a gas jet port 12a is formed substantially parallel to and between the flame holding plate 14.
A guide plate 16 which is slightly larger than the outer diameter of the gas nozzle 12 is provided so as to sandwich the plate. The guide plate 16 functions to guide the fuel gas 4 ejected from the gas ejection port 12a in a direction perpendicular to the central axis of the gas nozzle 12.

The outer diameter of the flame holding plate 14 is smaller than the inner diameters of the air cylinder 8 and the air cone 10. Therefore, between the both,
An air port 20 for ejecting the combustion air 2 in the empty cylinder 8 is formed. Moreover, in this example, by providing a plurality of (five in this example) baffle plates 18 between the outer peripheral portion of the flame holding plate 14 and the air cone 10, the air port 20 is blown out in the circumferential direction of the gas nozzle 12. It is divided into the same number as the outlets 12a (that is, five in this example). Therefore, the combustion air 2 is jetted from each air port 20 in a divided form. Moreover, each air port 20 corresponds to each gas ejection port 1 of the gas nozzle 12.
The phase (position in the circumferential direction) is shifted from 2a. More specifically, as can be seen from FIG. 2, the center of each air port 20 is located substantially on the center line between two adjacent gas ejection ports 12a. The position of each baffle plate 18 can be adjusted back and forth so that no gap is created between each baffle plate 18 and the flame stabilizing plate 14 when the position of the air cone 10 is shifted. There is.

3 and 4 schematically show the combustion state in the gas burner.

As can be seen from both figures, since the air port 20 is divided in the above gas burner, the flame 24
Becomes a radially divided shape, and its combustion temperature falls appropriately. The fact that the phase of each air port 20 is offset from the gas ejection port 12a of the gas nozzle 12 also contributes to lowering the combustion temperature appropriately. As a result, the NO _X concentration decreases.

For example, as shown in FIG. 5, each air port 20
When the phase shift angle between the gas jet port 12a and the gas jet port 12a is changed, the NO _X concentration becomes the minimum when the phase shift angle is around 36 degrees. In the above example, the air port 20 is divided into five, so 36
At the time of rotation, the center of each air port 20 is located substantially on the center line between two adjacent gas ejection ports 12a. Incidentally, NO _X concentration in the graph is O ₂ = 0% converted value (the same applies to other graphs).

Further, in the above gas burner, since the air cone 10 which spreads toward the end is provided at the tip portion of the air cylinder 8, the flame 24 spreads widely to the outside, and the exhaust gas circulation flow 26 near the tip portion of the gas burner also. Since the amount increases, the so-called self-recirculation amount becomes large, and these also contribute to appropriately lowering the combustion temperature, and the NO _X concentration further decreases.

For example, as shown in FIG. 6, the air cone 1
When the end spread angle θ of 0 (see FIG. 1) is changed, the NO _X concentration decreases as the angle θ increases. However, conversely, the concentration of CO (carbon monoxide) in the exhaust gas rises, and it is preferable that both concentrations are low, and especially CO
Since the concentration is preferably 50 ppm or less in actual use, the divergence angle θ of the air cone 10 is preferably greater than 0 degrees and 20 degrees or less.

Further, as in the above embodiment, the air cone 10
When the position of is set to be adjustable back and forth, the flow velocity of the combustion air 2 ejected from each air port 20 can be adjusted by it, so that the combustion range can be changed with one gas burner and It is also possible to select a low NO _x state.

FIG. 7 is a sectional view showing a gas burner according to another embodiment of the present invention. FIG. 8 is a front view of the gas burner of FIG. 7.

This gas burner is provided with a cylindrical air cylinder 8 to which the combustion air 2 is supplied from the outside via the wind box 6 in this example. An air cone 10 may be provided at the tip of the air cylinder 8 as described later, but it is not provided in this embodiment.

Inside the air cylinder 8, a cylindrical gas nozzle 12 to which the fuel gas 4 is supplied from the outside is provided coaxially therewith. Further, in this example, a pilot burner 22 is provided beside it. The gas nozzle 12 has a plurality of (five in this example) gas outlets 12b for ejecting the fuel gas 4 along the central axis of the gas nozzle 12 around the tip end face portion thereof at substantially equal intervals. There is.

Further, inside the gas nozzle 12, an inner cylinder 28 is provided coaxially with the gas nozzle 12 from the outside to which the combustion air 2 is supplied via the wind box 6 in this example. The tip of this inner cylinder 28 projects from the gas nozzle 12,
Around the tip, the combustion air 2 is ejected in a direction substantially perpendicular to the central axis of the inner cylinder 28, and the same number as the gas ejection ports 12b of the gas nozzle 12 (that is, five in this example). ) Primary air openings 28a are provided at substantially equal intervals. Therefore, the combustion air 2 is discharged from each primary air port 28a.
Erupts in a divided form. Moreover, each primary air port 28a
Are out of phase with each gas outlet 12b of the gas nozzle 12 (position in the circumferential direction). More specifically, as can be seen from FIG. 8, the center of each primary air port 28a is located substantially on the center line between two adjacent gas ejection ports 12b.

The inner cylinder 28, which is the tip of the gas nozzle 12.
The inner cylinder 28 is provided around the root side of the primary air port 28a.
The flame holding plate 14 is provided in such a manner as to penetrate.
That is, in this example, due to the notch of the flame holding plate 14,
Each gas ejection port 12b of the gas nozzle 12 is formed.
The flame stabilizing plate 14 has a large number of small holes 14a for producing an appropriate mixture with the fuel gas 4 ejected from the gas ejection port 12b.
Is provided.

A guide plate 16 which is slightly larger than the outer diameter of the inner cylinder 28 is provided on the tip end surface of the inner cylinder 28 so as to sandwich the primary air port 28a substantially parallel to and with the flame holding plate 14.
Is provided. This guide plate 16 is used for the gas ejection port 1
It serves to guide the fuel gas 4 ejected from 2b and the combustion air 2 ejected from the primary air port 28a in a direction perpendicular to the central axis of the gas nozzle 12.

The outer diameter of the flame holding plate 14 is equal to the inner diameter of the air cylinder 8 in this example, and there is no gap between them. However, in this example, by providing a plurality of (five in this example) notches on the outer peripheral portion of the flame holding plate 14, between the air cylinder 8 and
Secondary air port 20a for ejecting combustion air 2 in the empty cylinder 8
Are divided in the circumferential direction of the gas nozzle 12 into the same number as the gas ejection ports 12b (that is, five in this example). Therefore, the combustion air 2 is supplied from each secondary air port 20a.
Erupts in a divided form. Moreover, each secondary air port 20a
Are out of phase with the respective gas outlets 12b of the gas nozzle 12. More specifically, as can be seen from FIG. 8, the centers of the respective secondary air openings 20a are located substantially on the center line between two adjacent gas ejection openings 12b. That is, each secondary air port 20a and each primary air port 28
It is provided in almost the same phase as a.

9 and 10 schematically show the combustion state in this gas burner.

Also in the case of this gas burner, the primary air port 28
a and the secondary air port 20a are divided, and are in phase with each other and out of phase with the gas ejection port 12b of the gas nozzle 12, the flame 24 has a radially divided shape and spreads to the outside. The combustion temperature is appropriately lowered, and the exhaust gas circulation flow 26 is increased. As a result, NO _X is sufficiently reduced without providing the air cone 10 as in the embodiment of FIG.

For example, as shown in FIG. 11, when the phase shift angle between each gas ejection port 12b and each primary air port 28a is changed, the NO _X concentration becomes the minimum when the phase shift angle is around 36 degrees. Become. In this example, since the primary air port 28a is divided into 5, the center of each primary air port 28a is located substantially on the center line between two adjacent gas ejection ports 12b at 36 degrees.

Similarly, as shown in FIG. 12, when the phase shift angle between each gas outlet 12b and each secondary air port 20a is changed, the NO _x concentration is still around 36 degrees. It is the smallest. In this example, the secondary air port 20a is also divided into five, so at 36 degrees, the center of each secondary air port 20a is located substantially on the center line between two adjacent gas ejection ports 12b, and each primary air port 20a is It is in phase with the air port 28a.

Further, FIG. 14 shows the data when an air cone is further provided. When the end divergence angle θ is 0 degree, it is the same as when the air cone 10 is not provided, and the NO _x concentration at that time is approximately. 45 ppm, which is shown in FIG.
This corresponds to the case where the divergence angle θ of the air cone 10 is set to about 15 degrees in the embodiment.

Further, in the gas burner of this embodiment, the combustion air 2 is jetted also from the primary air port 28a in the vicinity of the gas jet port 12b, so that the stability of the flame 24 during combustion is higher than that of the embodiment of FIG. The effect of improving is also obtained.

The divergent air cone 10 as described above may be added to the embodiment of FIG. An example of doing so is shown in FIG. Also in this example, it is preferable that the positions of the air cone 10 and the baffle plate 18 can be adjusted, as in the case of the embodiment of FIG.

When the air cone 10 is provided, as in the case of the embodiment of FIG. 1, the flame 24 spreads to the outside more greatly, and moreover, the exhaust gas circulation flow 26 near the tip of the gas burner also increases, so-called self-recirculation. The circulation amount becomes larger, and these also contribute to appropriately lowering the combustion temperature, and further lowers the NO _X concentration.

Also in the case of this example, as shown in FIG. 14, when the divergence angle θ of the air cone 10 is changed, the NO _x concentration decreases as the angle θ increases. However,
On the contrary, the CO concentration in the exhaust gas rises, and as described above, the CO concentration is preferably 50 ppm or less in actual use. Therefore, the divergence angle θ of the air cone 10 in this example is greater than 0 degrees and is 18 degrees or less. It is preferable that the temperature is not more than a degree.

In any of the above embodiments, the gas nozzles 12 have the gas ejection ports 12a and 12b and the air port 2.
0, the case where the number of the primary air ports 28a and the number of the secondary air ports 20a are five is illustrated, but the number is not limited to five, and may be appropriately increased or decreased according to the size of the entire gas burner and the like. .

[0038]

As described above, according to the gas burner of claim 1, since the air ports are divided and the phase of each air port is shifted from the gas ejection port of the gas nozzle, the flame is divided radially. becomes form, because the combustion temperature drops to a suitable, it is possible to reduce the concentration of NO _X in the exhaust gas.
Moreover, since the end of the air cylinder is provided with a diverging air cone, the flame spreads greatly outward, and the exhaust gas circulation flow also increases, so these also contribute to lowering the combustion temperature appropriately, and NO _x concentration Can be further lowered.

Further, according to the gas burner of the second aspect, since the primary air port and the secondary air port are divided and are in phase with each other and out of phase with the gas ejection port of the gas nozzle, the flame is radial. It has a divided shape, and the spread to the outside is also large, which lowers the combustion temperature appropriately, increases the exhaust gas circulation flow, and can sufficiently reduce the NO _x concentration in the exhaust gas without providing an air cone. You can Moreover, since the combustion air is ejected from the primary air port in the vicinity of the gas ejection port, it is possible to obtain the effect of improving the stability of the flame during combustion.

[Brief description of drawings]

FIG. 1 is a sectional view showing a gas burner according to an embodiment of the present invention.

2 is a front view of the gas burner of FIG. 1. FIG.

FIG. 3 is a cross-sectional view schematically showing a combustion state in the gas burner of FIG.

FIG. 4 is a front view of the gas burner of FIG.

5 is a graph showing an example of measurement results of the relationship between the NO _x concentration and the phase shift angle between the gas ejection port and the air port in the gas burner of FIG. 1.

6 is a graph showing an example of measurement results of the relationship between the divergence angle of the air cone and the NO _X concentration and CO concentration in the gas burner of FIG. 1.

FIG. 7 is a sectional view showing a gas burner according to another embodiment of the present invention.

FIG. 8 is a front view of the gas burner of FIG.

FIG. 9 is a sectional view schematically showing a combustion state in the gas burner of FIG.

FIG. 10 is a front view of the gas burner of FIG.

11 is a graph showing an example of measurement results of the relationship between the NO _x concentration and the phase shift angle between the gas ejection port and the primary air port in the gas burner of FIG. 7.

FIG. 12 is a graph showing an example of measurement results of the relationship between the phase shift angle between the gas ejection port and the secondary air port and the NO _x concentration and the CO concentration in the gas burner of FIG. 7.

FIG. 13 is a cross-sectional view showing an example in which an air cone is attached to the gas burner of FIG.

FIG. 14 is a graph showing an example of measurement results of the relationship between the divergence angle of the air cone and the NO _x concentration and the CO concentration in the gas burner of FIG.

FIG. 15 is a cross-sectional view showing an example of a conventional gas burner.

[Explanation of symbols]

 2 Combustion air 4 Fuel gas 8 Empty cylinder 10 Air cone 12 Gas nozzle 12a, 12b Gas jet 14 Flame holding plate 14a Small hole 16 Guide plate 20 Air port 20a Secondary air port 28 Inner cylinder 28a Primary air port

Claims (2)

[Scope of utility model registration request] 1. An air cylinder to which combustion air is supplied from the outside, a diverging air cone provided at the tip of the air cylinder, and a fuel gas provided coaxially with the air cylinder from the outside. A cylindrical gas nozzle to which is supplied, having a plurality of gas ejection ports for ejecting the fuel gas in a direction substantially perpendicular to the central axis of the gas nozzle around its tip end at substantially equal intervals, A flame holding plate having a large number of small holes provided around the gas nozzle of the gas nozzle, and a flame holding plate provided substantially parallel to the flame holding plate at the tip end face of the gas nozzle. An air port for ejecting combustion air in the air cylinder, which is formed between the guide plate having a larger outer diameter, the flame holding plate and the air cone, and the gas ejection port in the circumferential direction of the gas nozzle. Divided into the same number as And the center of each air port is located approximately on the center line between adjacent gas ejection ports. 2. An air cylinder to which combustion air is supplied from the outside, and a cylindrical gas nozzle provided coaxially with the air cylinder and supplied with fuel gas from the outside,
Around the tip end face portion, a plurality of gas ejection ports for ejecting the fuel gas along the central axis of the gas nozzle are provided at substantially equal intervals, and the gas nozzle is provided in the gas nozzle coaxially therewith and burns from the outside. An inner cylinder to which the working air is supplied, the front end of which protrudes from the gas nozzle, and a plurality of combustion air are jetted around the front end of the inner cylinder in a direction substantially perpendicular to the central axis of the inner cylinder. The gas nozzles have the same number of primary air ports as the gas outlets at substantially equal intervals, and the centers of the respective primary air ports are located substantially on the center line between the adjacent gas outlets. A flame holding plate which is provided around and has a large number of small holes; a guide plate which is provided on the tip end face portion of the inner cylinder substantially parallel to the flame holding plate and is larger than the outer diameter of the inner cylinder; Form between the flame holding plate and the air cylinder Secondary air outlets for ejecting combustion air in the air cylinder, which are divided into the same number as the gas outlets in the circumferential direction of the gas nozzle, and the centers of the respective secondary air outlets are adjacent to each other. And a gas burner located substantially on the center line between the matching gas ejection ports.