JP2894057B2 - Combustion equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lean-burn combustion apparatus for burning two types of mixture, a lean mixture and a rich mixture.

[0002]

2. Description of the Related Art In a conventional combustion system, an all-primary air combustion system is effective as a combustion system capable of high-density combustion by shortening the flame and reducing NOx emissions. However, in principle, the combustion range is narrow,
Poor flame stability.

[0003] As a combustion method for improving this and achieving a low NOx reduction, a lean mixture having a large excess air ratio and a rich mixture having a small excess air ratio are combusted to convert the lean mixture flame into a rich mixture flame. It is well known that a so-called light-and-dark combustion method in which the above-described method is used is effective. In the combustion device of the lean-burn type, a separation passage for supplying a lean mixture and a rich mixture is necessary. Conventionally, as shown in FIGS. 3 and 4, for example, as shown in FIGS. A main mixing chamber 23 for producing a lean mixture, and a sub-mixing chamber 24 for producing a rich mixture having a higher gas concentration than the main mixing chamber 23.
And a light mixture passage 2 for guiding the light mixture to the flame plate 22.
5 from the periphery of the light mixture passage 25,
The dense mixture passage 26 leading to 2 is separated and formed by a partition wall 27. A flame is also formed on the partition wall 27 for separating the passage, and the partition wall 2 is formed in order to effectively use the area.
A gap 28 of about 0.2 to 3 mm between the nozzle 7 and the flame plate 22
Was provided. That is, the interior of the partition wall 27 is
5, a plurality of tubular portions 29 having a peripheral portion as a rich mixture passage are protruded, and a gap 28 is provided between the upper end of the tubular portion 29 and the flame hole plate 22.

[0004]

However, by providing the gap 28 between the tubular portion 29 of the partition wall 27 and the flame hole plate 22, the density of the portion indicated by the dotted line in FIG. There is a drawback that the air-fuel mixture is excessively diluted with a light air-fuel mixture, and the flame holding ability is locally reduced, and there is room for improvement.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light-and-light combustion type combustion apparatus which has an enhanced flame holding capacity of a rich mixture and an increased area efficiency of a perforated plate, and has a vibration combustion suppression effect and a combustion noise reduction effect. It is.

[0006]

The present invention has the following configuration to achieve the above object.

That is, a light-mixture passage for guiding a lean mixture to a flame plate and a rich-mixture passage for guiding a rich mixture from around the light mixture passage to a flame plate are separated and formed by partition walls. A tubular portion having a light mixture passage inside and a dense mixture passage around the wall is projected from the partition wall, and a step is provided at the upper end of the tubular portion. However, adjacent portions are made smaller.

[0008]

The light mixture supplied to the burner plate from the light mixture passage forms a main flame on the upper surface of the burner plate, and is supplied to the burner plate from the rich mixture passage formed around the light mixture passage. The rich mixture thus formed forms a supplementary flame around the main flame on the upper surface of the flame hole plate to stably maintain the main flame. At this time, since the gap between the upper end of the tubular portion and the flame hole plate having a light mixture passage therein is made smaller by the step provided at the upper end of the tubular portion, the portion adjacent to the tubular portion is reduced. The adjoining part of the tubular part has little mixture of the lean mixture and the rich mixture, and the rich mixture is not excessively diluted by the lean mixture, preventing the occurrence of a local flame holding capacity decrease part and the main flame Increase stability.

[0009]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.
FIG. 2 is a plan view taken along the line AA of FIG. 1 and will be specifically described below with reference to the drawings.

Reference numeral 1 denotes a combustion device, which has a flame plate 3 such as a ceramic plate provided with a large number of flame holes 2 on an upper portion thereof. A sub-mixing chamber 5 for forming a rich mixture having a high gas concentration is formed by a partition 6. Reference numeral 7 denotes a light mixture passage which guides the light mixture to the flame plate 3, and projects from the periphery of the light mixture passage 7 to a rich mixture passage 8 which guides the rich mixture to the flame plate 3 to the partition wall 6. The plurality of tubular portions 9 are formed separately. Reference numeral 10 denotes a step provided at the upper end of the tubular portion 9, which reduces a gap 11 between opposing portions on a line connecting the centers of adjacent tubular portions 9 of the plurality of tubular portions 9 arranged below the flame-hole plate 3, The other parts are provided to be large.

When the combustion apparatus 1 is burning, the lean mixture produced in the main mixing chamber 4 is supplied from the lean mixture passage 7 to the flame plate 3 to form a main flame on the upper surface of the flame plate 3. In addition, sub mixing room 5
Is supplied from the rich mixture passage 8 formed around the tubular portion 9 having the light mixture passage 7 to the upper portion of the flame hole plate 3. A supplementary flame is formed around the main flame. The main flame can be stably burned by the flame holding action of the supplementary flame. At this time, the gap between the upper end of the tubular portion 9 having the light mixture passage 7 therein and the flame hole plate 3 is formed by the step 10 provided at the upper end of the tubular portion 9 so that the tubular portions 9 are adjacent to each other and face each other. The part where the distance is short is made smaller, so the part where the rich mixture was conventionally diluted most by the light mixture and became the local flame holding capacity reduction part is the mixture of the light mixture and the rich mixture. Is reduced, and a supplementary flame maintaining the flame holding ability can be formed.

Incidentally, the shape of the step 10 may be appropriately formed, that is, it may be formed at the upper end of the tubular portion 9 so as to partially narrow the gap 11.

[0013]

As described above, according to the present invention, a step is provided at the upper end of a tubular portion having a light mixture passage inside and a rich mixture passage around the periphery, and the step forms a gap between the upper end of the tubular portion and the flame hole plate. Since the portion adjacent to the tubular portion is made smaller, the rich mixture is not excessively diluted by the light mixture, the flame holding capacity of the supplementary flame is maintained, and the stability of the main flame is improved. By forming the gap, the area efficiency of the flame hole plate can also be increased, and a vibration combustion suppressing effect and a combustion noise reducing effect can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a combustion apparatus showing one embodiment of the present invention.

FIG. 2 is a plan view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view of a main part of a combustion apparatus showing a conventional example.

FIG. 4 is a plan view as viewed in the direction of arrows BB in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion device 3 Flame plate 6 Partition wall 7 Light mixture passage 8 Rich mixture passage 9 Tubular part 10 Step 11 Gap

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F23D 14/02 F23D 14/14-14/16 F23C 11/00 329-330

Claims (1)

(57) [Claims] 1. A method in which a light mixture passage for guiding a light mixture to a flame plate and a rich mixture passage for guiding a rich mixture from the periphery of the light mixture passage to the flame plate are formed separately by partition walls. A tubular portion having a light mixture passage inside and a dense mixture passage around the wall is projected from the partition wall, and a step is provided at the upper end of the tubular portion. A combustion device characterized in that the portion adjacent to the combustion device is made smaller.