JPH058208U - Gas burner - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a gas burner capable of reducing the NO _X concentration in exhaust gas. This gas burner includes an air cylinder 8, a divergent air cone 10 provided at a tip portion thereof, a gas nozzle 12 provided in the air cylinder 8, and a gas ejection port 12a thereof.
A guide plate 16 and a flame holding plate 14 provided in front of and behind,
It has an air port 20 formed between the flame holding plate 14 and the air cone 10. The air openings 20 are divided into the same number as the gas ejection openings 12a in the circumferential direction of the gas nozzle 12, and the centers of the air openings 20 are located substantially on the center line between two adjacent gas ejection openings 12a. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

The present invention relates to a gas burner, and more specifically to a so-called low NO _x gas burner in which the concentration of NO _x (nitrogen oxide) in exhaust gas is reduced.

[0002]

[Prior art]

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

[0003]   This gas burner is installed in an air cylinder 30 to which combustion air 2 is supplied from the outside. A gas nozzle 32 to which the fuel gas 4 is supplied from the outside is provided coaxially with The flame holding plate 34 is provided around the tip of the nozzle 32. Gas nozzle 3 A plurality of gas ejection ports 32a are provided at the tip of No. 2, and a large number of flame holding plates 34 are provided. Is provided with a small hole 34a. In addition, between the outer peripheral portion of the flame holding plate 34 and the air cylinder 30. A ring-shaped air port 36 is formed in the. The pilot burner etc. The illustration is omitted.

[0004]

[Problems to be solved by the device]

In the above gas burner, the fuel gas 4 is ejected radially 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 becomes planar. 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]

[Means for Solving the Problems]   In order to achieve the above object, the first gas burner of the present invention uses an external combustion air blower. The air cylinder to which the air is supplied and the divergent air cord provided at the tip of this air cylinder. And a fuel gas is supplied from the outside, which is coaxial with the air cylinder. This is a cylindrical gas nozzle that has fuel gas around its tip. There are multiple gas outlets, which are ejected almost at right angles to the center axis of the It is often installed near the root side of the gas nozzle of this gas nozzle. A flame holding plate having a small number of small holes, and the flame holding plate at the tip end face of the gas nozzle is almost flat. A guide plate that is provided in a row and is larger than the outer diameter of the gas nozzle, and the flame holding plate and the front Air which is formed between the air cone and ejects combustion air in the air cylinder. The mouth is divided into the same number as the gas ejection port in the circumferential direction of the gas nozzle. Moreover, the center of each air port should be located approximately on the center line between the adjacent gas outlets. It is characterized by including.

[0007]   The second gas burner of the present invention is an air cylinder to which combustion air is supplied from the outside. The fuel gas is supplied from the outside by being installed coaxially with the air cylinder. It is a cylindrical gas nozzle that has a fuel gas around the tip end face. With a plurality of gas ejection ports that eject along the central axis of the It is installed coaxially with the gas nozzle of the Inner cylinder, the tip of which protrudes from the gas nozzle and the circumference of the tip. In the surrounding area, a plurality of front and front The gas nozzles have the same number of primary air openings as the gas ejection openings at approximately equal intervals, and If the center of the next air port is located approximately on the center line between the adjacent gas outlets, A flame holding plate provided around the tip of the nozzle and having a large number of small holes; It is provided on the tip end face of the cylinder almost parallel to this flame holding plate and is larger than the outer diameter of the inner cylinder. A guide plate, and between the flame holding plate and the air cylinder, A secondary air port for ejecting combustion air, the gas being in the circumferential direction of the gas nozzle. Gas outlets divided into the same number as the jet outlets, and the centers of the secondary air outlets are adjacent to each other And those located approximately on the center line between.

[0008]

[Action]

In the case of any of the above gas burners, the flame is radially divided, and the spread to the outside is large, whereby the combustion temperature is appropriately lowered, and the exhaust gas recirculation flow is also increased, so that the NO _x concentration in the exhaust gas is increased. It was confirmed by an experiment that it was lowered.

[0009]

【Example】

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

[0010]   This gas burner receives the combustion air 2 from the outside via the wind box 6 in this example. A cylindrical air cylinder 8 to be supplied is provided. The tip of this air cylinder 8 is for combustion A divergent air cone 10 is provided for ejecting the air 2 obliquely outward. It The position of this air cone is indicated by arrow A according to the required amount of combustion. Can be adjusted back and forth.

[0011]   Inside the empty cylinder 8, there is a cylindrical shape in which the fuel gas 4 is supplied from the outside coaxially therewith. A gas nozzle 12 is provided. Also in this example, the pilot burner 2 beside it Two are provided. The gas nozzle 12 has a fuel gas 4 around the tip. Of a plurality of (in this example (5) gas ejection ports 12a are provided at substantially equal intervals.

[0012]   The gas nozzle 12 has a gas nozzle 12 around the base of the gas outlet 12a. A flame holding plate 14 is provided in such a way that the rule 12 penetrates. In this flame holding plate 14 Is a large number for producing an appropriate mixture with the fuel gas 4 ejected from the gas ejection port 12a. Is provided with a small hole 14a.

[0013]   The tip end face of the gas nozzle 12 is substantially parallel to the flame holding plate 14 and between it. A guide that is slightly larger than the outer diameter of the gas nozzle 12 so as to sandwich the gas ejection port 12a. A plate 16 is provided. The guide plate 16 is ejected from the gas ejection port 12a. It functions to guide the fuel gas 4 in a direction perpendicular to the central axis of the gas nozzle 12. It

[0014]   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, an air port 20 for ejecting the combustion air 2 in the air cylinder 8 is formed between them. ing. Moreover, in this example, a plurality of parts are provided between the outer peripheral portion of the flame holding plate 14 and the air cone 10. By providing baffles 18 (five in this example), The same number as the gas outlets 12a in the circumferential direction of the nozzle 12 (that is, five in this example). It is divided. Therefore, the combustion air 2 is ejected from each air port 20 in a divided form. To do. Moreover, each air port 20 is in phase with each gas ejection port 12a of the gas nozzle 12 ( The position in the circumferential direction) is shifted. More specifically, as can be seen from FIG. The center of the air port 20 is located approximately on the center line between two adjacent gas ejection ports 12a. I am trying to do it. The position of each baffle 18 can be adjusted back and forth. If the position of the air cone 10 is displaced by that, the baffle plates 18 and the A gap is not formed between the flame plate 14 and the flame plate 14.

[0015]   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 gas burner, the flame 24 has a radially divided shape, and the combustion temperature thereof is appropriately lowered. 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, when the phase shift angle between each air port 20 and each gas ejection port 12a is changed, the NO _X concentration becomes the minimum when the phase shift angle is around 36 degrees. . In the above example, since the air port 20 is divided into five, the center of each air port 20 is located substantially on the center line between two adjacent gas ejection ports 12a at 36 degrees. 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 end portion of the air cylinder 8, the flame 24 spreads greatly to the outside, and the exhaust gas circulation flow 26 near the tip end 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, when the divergence angle θ of the air cone 10 (see FIG. 1) is changed, the NO _X concentration decreases as the angle θ increases. However, on the contrary, the concentration of CO (carbon monoxide) in the exhaust gas rises, and it is preferable that both of them are low. Particularly, in actual use, the CO concentration is preferably 50 ppm or less. The angle θ is preferably greater than 0 degrees and 20 degrees or less.

Further, if the position of the air cone 10 can be adjusted back and forth as in the above-described embodiment, the flow velocity of the combustion air 2 ejected from each air port 20 can be adjusted thereby, so that one unit It is possible to change the combustion range with the gas burner and to select the lowest NO _x state.

[0021]   FIG. 7 is a sectional view showing a gas burner according to another embodiment of the present invention. Figure 8 FIG. 8 is a front view of the gas burner of FIG. 7.

[0022]   This gas burner receives the combustion air 2 from the outside via the wind box 6 in this example. A cylindrical air cylinder 8 to be supplied is provided. The tip of the air cylinder 8 will be described later. The air cone 10 may be provided so that it is not provided in this embodiment. .

[0023]   Inside the empty cylinder 8, there is a cylindrical shape in which the fuel gas 4 is supplied from the outside coaxially therewith. A gas nozzle 12 is provided. Also in this example, the pilot burner 2 beside it Two are provided. This gas nozzle 12 has a fuel gas A plurality of (four in this example) ejecting the gas 4 along the central axis of the gas nozzle 12 The gas ejection ports 12b are provided at substantially equal intervals.

[0024]   Further, inside the gas nozzle 12, coaxially therewith, from the outside, in this example, the wind box. An inner cylinder 28 to which the combustion air 2 is supplied via 6 is provided. This inner cylinder 28 has a tip portion projecting from the gas nozzle 12 and is surrounded by a fuel. A plurality of firing air 2 are jetted in a direction substantially perpendicular to the central axis of the inner cylinder 28, and The same number of primary airs as the gas outlets 12b of the gas nozzle 12 (that is, five in this example) The mouths 28a are provided at substantially equal intervals. Therefore, combustion from each primary air port 28a The working air 2 is jetted in a divided form. Moreover, each primary air port 28a is a gas nozzle. The phase (position in the circumferential direction) of each of the 12 gas ejection ports 12b is shifted. More concrete Specifically, as can be seen from FIG. 8, the center of each primary air port 28a has two adjacent air centers. It is located almost on the center line between the gas ejection ports 12b.

[0025]   At the tip of the gas nozzle 12 and on the root side of the primary air port 28a of the inner cylinder 28. A flame holding plate 14 is provided around the inner cylinder 28 so as to penetrate therethrough. Tsuma In this example, the gas nozzle 12 ejects each gas by the notch of the flame holding plate 14. It forms the mouth 12b. The flame holding plate 14 is jetted from the gas jet port 12b. A large number of small holes 14a for making a proper mixture with the fuel gas 4 are provided.

[0026]   At the tip end face portion of the inner cylinder 28, a primary line is formed substantially parallel to the flame holding plate 14 and between it. A guide plate 16 which is somewhat larger depending on the outer diameter of the inner cylinder 28 is provided so as to sandwich the air port 28a. It has been burned. The guide plate 16 is used for the fuel gas 4 ejected from the gas ejection port 12b. And the combustion air 2 ejected from the primary air port 28a is fed to the central axis of the gas nozzle 12. It acts to guide in a direction perpendicular to.

[0027]   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 a gap between them. There is no time. However, in this example, a plurality of (five in this example) the outer peripheral portion of the flame holding plate 14 By providing the notch, the combustion air 2 in the air cylinder 8 is separated from the air cylinder 8. The secondary air port 20a which jets out is the gas jet port 12b in the circumferential direction of the gas nozzle 12. And the same number (that is, five in this example). Therefore, each secondary Combustion air 2 is jetted from the air port 20a in a divided form. Moreover, each secondary air The port 20a is out of phase with each gas ejection port 12b of the gas nozzle 12. Yo More specifically, as can be seen from FIG. 8, the centers of the secondary air ports 20a are adjacent to each other. It is located almost on the center line between the two gas outlets 12b. That is, each The secondary air port 20a and each of the primary air ports 28a are provided in substantially the same phase.

[0028]   9 and 10 schematically show a combustion state in this gas burner.

Also in the case of this gas burner, since the primary air port 28a 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 is radial. It has a divided shape, and also has a large spread to the outside, which appropriately lowers the combustion temperature and increases the exhaust gas circulation flow 26. 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 ejection port 12b and each secondary air port 20a is changed, the NO _x concentration is about 36 degrees when the NO _x concentration is still around. 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 approximately on the center line between two adjacent gas ejection ports 12b, and It is in phase with the air port 28a.

Further, FIG. 14 shows data when an air cone is further provided. When the end spread 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 about. It is 45 ppm, which corresponds to the case where the divergence angle θ of the air cone 10 in the embodiment of FIG. 1 is set to about 15 degrees.

[0033]   Moreover, in the gas burner of this embodiment, the primary air port 2 near the gas ejection port 12b is used. Since the combustion air 2 is also ejected from 8a, the flame 2 at the time of combustion is higher than that in the embodiment of FIG. The effect of improving the stability of No. 4 is also obtained.

[0034]   In addition to the embodiment shown in FIG. Is also good. An example of doing so is shown in FIG. Also in the case of this example, in the case of the embodiment of FIG. As with the case, make sure that the positions of the air cone 10 and baffle plate 18 can be adjusted. Is preferred.

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 The amount of recirculation becomes larger, and these also contribute to appropriately lowering the combustion temperature, and further lowers the NO _X concentration.

Also in 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 larger than 0 degree. Is preferably 18 degrees or less.

[0037]   In any of the above embodiments, the gas ejection port 12a of the gas nozzle 12, 12b, the air port 20, the primary air port 28a and the secondary air port 20a are five Although illustrated, these are not limited to five, and the entire gas burner You may increase or decrease according to the size etc.

[0038]

[Effect of device]

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 becomes a radially divided form, and because the combustion temperature is reduced to a proper, 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 its 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 cylinders 10 air cones 12 gas nozzles 12a, 12b Gas outlet 14 Flame retaining 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 to which fuel gas is supplied 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.