JPH0596722U - Combustion device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a combustion device that can reduce NOx emissions and that has a flame nozzle plate with a wide combustion variable width. In a combustion apparatus provided with a flame nozzle plate 21 for burning a premixed gas, the flame nozzles 20 are arranged so as to form a plurality of flame nozzle groups 24, and the flame nozzles are arranged between the flame nozzle groups 24. The flame openings 2 that form the flame opening groups 24 with a distance D that is wider than the distance d between the adjacent flame openings 20 in the flame opening groups 24.
A combustion device in which 0s are arranged so that they do not exist in the central portion of the flame nozzle group 24 but only in the peripheral portion.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a combustion device for burning a premixed gas of fuel and air, and more particularly to a structure of a flame nozzle plate having a large number of flame nozzles.

[0002]

[Prior Art]

 BACKGROUND ART A so-called Bunsen burner, which burns a premixed gas obtained by premixing fuel and air with a flame nozzle plate having many flame nozzles, is well known. In this premixing type combustion device, in order to obtain a stable combustion state, the flame openings in the flame opening plate, the shape around the flame openings, and the arrangement of the flame openings are important factors.

As an improved arrangement of the flame openings, for example, as shown in FIG. 6, a large number of flame openings 2 are arranged on a flame opening plate 1 so as to form a flame opening group 3, and the flame opening group is formed. A structure is known in which three or more of them have a certain distance (for example, Japanese Utility Model Laid-Open No. 63-49134). By adopting such a structure, the flame mouth plate can be made compact, and as shown in FIG. 7, the circulation flow 4 is generated in the strip-shaped region between the flame mouth groups 3 where the flame mouths 2 do not exist. It is possible to improve the flame holding performance (performance that is difficult to blow out) of the flame from the flame openings 2 in each flame opening group 3.

[0004]

[Problems to be solved by the device]

 However, in the conventional flame nozzle plate as described above, since the flame nozzles 2 are relatively densely arranged at equal pitch over the entire area of each flame nozzle group 3, These flames interfered with each other and the temperature of the flames became too high, resulting in a large amount of NOx (nitrogen oxide) emissions. In particular, the flame temperature at the center of the flame nozzle group may rise. If the NOx emission amount is large, it becomes difficult to use the NOx emission amount in a combustion region where the NOx emission amount exceeds a certain value (for example, a region viewed from the primary air ratio).

In order to deal with this problem, there is a method in which the distance between the flame openings 2 is simply increased. However, although this method can reduce the flame temperature, the flame propagation speed also decreases at the same time, so that the flame holding performance is reduced. It causes the problem of getting worse.

The present invention focuses on the problems of the conventional device as described above, and an object of the present invention is to provide a combustion device that can reduce NOx emissions and that has a flame nozzle plate having a wide combustion variable width.

[0007]

[Means for Solving the Purpose]

 A combustion device of the present invention which meets this purpose is a combustion device having a flame plate having a large number of flame ports for burning a premixed gas of fuel and air, wherein the flame ports are connected to a plurality of flame port groups. The flame openings are arranged so that they are wider than the intervals between adjacent flame openings in each flame opening group, and the flame openings forming each flame opening group are It is arranged so that it does not exist in the central part of the mouth group but only in the peripheral part.

[0008]

[Action]

 In such a combustion device, since multiple flame openings are formed, a large number of flame openings can be compactly arranged, and the interval between flame openings is set wider than the interval between adjacent openings in each flame opening. Therefore, the flame holding performance is also improved by the circulation flow generated in this part. Further, in each flame mouth group, since the flame mouth does not exist in the central portion of the flame mouth group and exists only in the peripheral portion, mutual interference between the flames from the flame mouths in the central portion disappears, and it is The flame temperature in the central part, which had been high, is reduced. As a result, while the good flame holding performance is ensured by the array of flame ports, the amount of NOx generated is greatly reduced, and the variable combustion range is expanded accordingly.

[0009]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a combustion apparatus according to an embodiment of the present invention. In the figure, reference numeral 11 denotes a combustor. The combustor 11 is provided with a premixed gas 15 obtained by premixing atomized liquid fuel 13 from a nozzle 12 of a carburetor and air 14 accompanying with intake air. A passage 16 is provided. The premixed gas 15 is opened and supplied from the premixed gas passage 16 to the pressure equalizing chamber 18 after the flow passage is once narrowed by the throttle plate 17.

Inside the pressure equalizing chamber 18, a pressure equalizing plate 19 made of a porous plate having a high opening ratio, a wire mesh, or the like is provided. Due to the pressure loss due to the pressure equalizing plate 19, the pressure on the upstream side of the pressure equalizing plate 19 is made uniform and the flow rate passing through the pressure equalizing plate 19 is made uniform.

A flame vent plate 21 having a large number of flame vents 20 is provided above the pressure equalizing plate 19. The flames 20 are ignited, and the flames 22 as the internal flames are generated on the flame ports 20 and the flames 23 as the external flames are generated so as to wrap the flames 22 in a large size. In this embodiment, the flame vent plate 21 is composed of a ceramic plate.

The arrangement of the flame openings 20 in the flame opening plate 21 is as shown in FIG. First, the large number of flame ports 20 are arranged so as to form a plurality of flame port groups 24. In this embodiment, each flame port group 24 is formed in a rhombus shape. The distance D between each flame mouth group 24 is set to be wider than the distance d between the adjacent flame mouth groups 20 in each flame mouth group 24. In addition, in this embodiment, the shape of the flame port group 24 is a rhombus, but it may be another shape. However, in order to keep the inter-flame group spacing substantially constant, it is desirable that it is rectangular. In addition, in the present embodiment, the size of each flame port group 24 is fixed, but it may be different.

In each of the flame port groups 24, the flame ports 24 are arranged so as not to exist in the central portion 24 a of the diamond-shaped flame port group 24 but to exist only in the peripheral portion.

In the combustion apparatus configured as described above, the premixed gas 15 ejected upward from each flame port 24 is combusted, and a flame is generated on each flame port 24 as shown in FIG. To achieve. Between each of the flame port groups 24, there exists a band-shaped region in which the flame port 20 does not exist, and essentially no flame is generated from the flame port 20 in this portion, so that a circulating flow 25 occurs as shown in FIG. A high flame holding performance is ensured by the adjacent flame form maintaining function by the circulating flow 25 and the adjacent flames maintaining the flame form with each other because the interval d between adjacent flames is relatively small.

In each of the flame port groups 24, the flame port 24 does not exist in the central portion 24a, so that the flame from the flame port 20 is not formed directly above the flame port plate 21 in this portion. Therefore, a high temperature portion (high temperature flame) due to mutual interference of flames is not generated in this portion, and the amount of NO x generated is suppressed. The central portion 24a is a portion where the highest temperature flame is generated in the conventional apparatus as shown in FIGS. 6 and 7, for example, and is a portion where a large amount of NO x is generated. In the present invention, NOx generation mainly from this site is suppressed.

As a result of suppressing the NOx emission amount to a small amount, the combustion variable width is greatly expanded. For example, as shown in FIG. 4 by comparing the characteristics of the above-described apparatus with the conventional apparatus shown in FIGS. 6 and 7, the region of the primary air ratio capable of achieving low NOx is greatly expanded. Here, the primary air ratio refers to the ratio Qa / Qt of the theoretically required air amount Qt for combustion to the fuel of the premixed gas 15 and the actual used air amount Qa.

In the above embodiment, the flame port 20 is composed of a simple circular hole provided in the flame port plate 21, but the shape of the flame port itself and the shape around it can be arbitrarily set. .. For example, as shown in FIG. 5, it is possible to further improve the flame holding performance by providing a recess 32 on the flame generation side of the flame vent plate 31 and opening the flame vent 33 in the recess 32. is there.

[0018]

[Effect of the device]

 As described above, in the case of the combustion device of the present invention, no flame port is provided in the central part of each flame port group, but only in the peripheral part, so that a high-temperature flame is conventionally generated and NOx main It is possible to lower the temperature at the center of the flame outlet group, which was the source of generation, and while maintaining high flame holding performance through the formation of the flame outlet group, greatly reduce NOx emissions and achieve a wide combustion variable range. Can be realized.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of a combustion apparatus according to an embodiment of the present invention.

2 is an enlarged partial plan view of a flame vent plate of the apparatus of FIG. 1. FIG.

FIG. 3 is an enlarged partial vertical cross-sectional view taken along the line III-III of the flame nozzle plate of FIG.

FIG. 4 is a relationship diagram between NOx and a primary air ratio.

FIG. 5 is a vertical cross-sectional view around a flame port according to another embodiment.

FIG. 6 is a partial plan view of a conventional flame nozzle plate.

7 is an enlarged partial sub-sectional view taken along the line VII-VII of the flame mouth platen in FIG.

[Explanation of symbols]

 11 Combustion Device 12 Vaporizer Nozzle 13 Fuel 14 Air 15 Premixed Gas 16 Premixed Gas Passage 18 Pressure Equalizing Chamber 19 Pressure Equalizing Plate 20, 33 Flame Mouth 21, 31 Flame Mouth Plate 22 Flame 24 Flame Mouth Group 24a Flame Mouth Group Central part 25 Circulating flow 32 Recessed part

Claims (2)

[Scope of utility model registration request] 1. A combustion device provided with a flame nozzle plate having a large number of flame nozzles for burning a premixed gas of fuel and air, the flame nozzles being arranged so as to form a plurality of flame nozzle groups. In addition, between each flame mouth group, with a spacing wider than the spacing between adjacent flame mouths in each flame mouth group, and a flame mouth forming each flame mouth group, in the central portion of the flame mouth group A combustion device characterized by being arranged so that it does not exist but only in the peripheral portion. 2. The combustion apparatus according to claim 1, wherein the flame plate is made of ceramic.