JPH02306007A - Gas combustion burner of premixing type - Google Patents

Abstract

PURPOSE:To make it possible to maintain a stable frame shape against variation in the speed of injecting a premixed gas by forming groups of small holes of a combustion burner each of which consists of densely collected burner holes specified in A number and providing a specified distance among the groups and placing them on a flame holding body. CONSTITUTION:Groups of small holes 11, A, B, C,... are formed with a specified distance among them and in each of the groups A, B, C,... the flames from the small holes are formed without gathering together into one flame. With this arrangement, even if the supply pressure of a premixing gas is high combustion load is high, the flames are formed independently in each of the groups of small holes A, B, C... and the area d that contributes to combustion reaction becomes wide. Accordingly when the speed of injecting a premixed gas changes due to the variation in the supply pressure of the premixed gas, the equilibrium state of the injecting speed with the combustion speed is maintained, and even if the equilibrium is broken, it is restored easily and stable combustion is made.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] This invention relates to an improvement in a premixed gas combustion burner, and more particularly to a surface combustion burner having a large number of premixed gas orifices.

[Conventional technology]

In recent years, due to environmental issues such as air pollution, gas fuels such as city gas and LPG, which contain fewer harmful components in combustion gas, have been increasingly used in industry, and the number of industrial machines such as boilers that use gas burners is also increasing. are doing.

One type of these gas burners is a surface combustion burner. This surface combustion burner, for example, as shown in FIGS. 7 and 8, allows fuel gas to flow out through a flame stabilizer (2) in which a large number of micropores (1) are formed, and the surface of this flame stabilizer (2) is This is a type of flame that generates many small flames.

[Problem that the invention seeks to solve]

By the way, in the above-mentioned surface combustion burner, when the supply pressure of the premixture is increased in order to perform high-load combustion, the ejection speed of the premixture from the micropores (1) on the surface of the flame stabilizer (2) increases. Figure 9 (a)
As shown in ~(c), the flames become integrated with each other, and eventually become one flame that extends from the entire surface of the flame stabilizer.

As is well known, the combustion reaction takes place in a region (d) where the injection velocity of the premixture and the combustion velocity are balanced.

Therefore, in the above-mentioned conventional surface combustion burner, as the supply pressure of the premixture is increased, the combustion flame becomes unified, so that the above-mentioned combustion reaction region (d) becomes 1 as shown in FIG. 9(C). It becomes two flat surfaces. In this state, the combustion reaction area is small relative to the amount of premixed air supplied, the flame stability is poor, and combustion is accompanied by vibrations. In particular, when the ejection speed of the premixture changes due to fluctuations in the supply pressure of the premixture, the above-mentioned balanced state is easily lost, causing lift or blowout of the flame. Furthermore, when this type of burner is ignited, the flame instantly spreads over the entire surface of the surface combustion burner, so there is a problem that the impact at the time of ignition is large.

That is, at present, a small-sized, high-load combustion type surface combustion burner capable of stable combustion has not been technically achieved, and market demand for this type of burner is increasing.

[Means to solve the problem]

This invention was made in order to solve the above problem, and is a premixing type in which a premixed mixture is jetted out from a large number of small holes in a flame stabilizer to form a combustion flame on the surface of the flame stabilizer. The present invention is a premixed gas combustion burner characterized in that the small holes are arranged in groups of a predetermined number on a flame stabilizer with a predetermined interval between them.

[Function] According to the premixed gas combustion burner according to the present invention, the combustion flame formed on the flame stabilizer surface can be divided into a plurality of small groups to expand the area involved in the combustion reaction. A stable flame shape can be maintained even with fluctuations in the ejection speed of the premixture.

[Embodiment] FIGS. 1 to 3 show an embodiment of a premixed gas combustion burner according to the present invention.

In those drawings, 0ω is a flame stabilizer in which a large number of micropores (11) are formed as described above, and the difference from the conventional one is that the micropores (11) are arranged in groups of a predetermined number. (A), (B), (C)..., and each of these groups (A), (B), (
C)... They are arranged with a predetermined gap between them.

The flame stabilizer (10) in this example was previously proposed by the applicant (see Japanese Patent Application No. 143884/1984).
Window holes (21) are bored at the same pitch in each of a set of perforated steel plates QrjJ, and a heat-resistant spherical member (22) is fitted between the window holes (21) of this set of perforated steel plates Qal. It has an intricate structure. Then, this window hole (21) and the spherical member (22
) is made to function as a microhole (II) for blowing out the premixture.

In the flame stabilizer (10) having such a structure, the window hole 12
(When drilling the window holes Q (D), a predetermined number of holes are set as one group and the window holes Q (D) are drilled under the above-mentioned conditions.

According to the flame stabilizer (101) of this structure, one window hole (21
) is caused by the premixture ejected from the gap between the window hole (21) and the spherical member (22), and these flames face each other and become one flame. Then, as the supply pressure of the premixture is increased, the flame in the adjacent window hole (21) becomes integrated with the flame, becoming a larger flame. However, in the flame stabilizer (10) according to the present invention, (11) Each group (A), (B), (C)
... are formed at a predetermined distance from each other to form each group (^
).

(B), (C)... This is to prevent the flames from merging into one. Therefore, even if the supply pressure of the premixture is high and the combustion load is high, the flame will not flow through each group of small holes (A),
(B).

(C)... are formed independently, and the region (d) that contributes to the combustion reaction is wider than in the conventional case. Therefore, even if the injection velocity of the premixture changes due to fluctuations in the supply pressure of the premixture, a state of equilibrium with the combustion speed is maintained, and even if the equilibrium state is broken, it is easily recovered and stable. Combustion takes place.

Also, at the time of ignition, each group (A), (B
)... Because the flame is formed sequentially, the ignition sound, j
You can speak up to keep the attacks to a minimum.

In the above explanation, each group (A), (B)...
The number of small holes (11) for ejecting the premixture in each group is the same; The number of small holes (1) in the loop may also be different from each other. For example, as shown in FIG.
0) The number of small holes θ1) in the group located in the center may be increased, and the number of small holes θ1) in the group located in the peripheral portion may be reduced.

In this case, each group (A), (B) of small hole 01)
Since the resonant frequencies of the combustion vibrations for each burner are different from each other, the resonant frequencies are dispersed when looking at the burner as a whole, which has the advantage of effectively preventing the occurrence of combustion vibrations. Furthermore, the combustion flame stabilizer had a structure in which a spherical member was sandwiched between two perforated steel plates, but in this invention, porous materials such as foamed ceramics and ceramic grain sintered blocks were used. , as shown in Figure 5, flat and wavy ribbons (3
It may be a porous block in which 0) and (31) are laminated, and the shape is not limited to a flat plate shape, but may be a curved shape or a cylindrical shape.

Further, the shape of each group (A) is not limited to a square as shown in FIG. 1, but may be a diamond as shown in FIG. 4, and the shape is limited by the above embodiment. It's not a thing.

Furthermore, the above-mentioned small holes do not have to be formed for each group, and even if the flame stabilizer has small holes formed on the entire surface at a constant pitch, each small hole may be formed as shown in Fig. 5 above. A frame body (32) that divides holes into groups may be provided on the surface of the flame stabilizer (10).

〔Effect of the invention〕

As explained above, according to the premixed gas combustion burner according to the present invention, even if the burner has a large area and a high combustion load, a flame is formed in each group of small holes to suppress the combustion reaction area. Since it can be made large, a stable flame can be obtained even when the ejection speed of the premixture changes due to fluctuations in the supply pressure of the premixture. Therefore, the conventional problems of flame lift, blowout, vibration combustion, ignition shock, etc. can be solved, and the combustion load can be increased compared to conventional ones, so if the combustion amount is the same, it will be significantly It can be a small burner.

[Brief explanation of the drawing]

1 to 3 show an embodiment of a premixed gas combustion burner according to the present invention. 3(a) to 3(c) are side views for explaining the combustion state. FIGS. 4 to 6 are front views showing other embodiments of the present invention. Fig. 7 to Fig. 9 show an example of a conventional premix type surface combustion burner, in which Fig. 7 is a front view, Fig. 8 is a cross-sectional view of main parts, and Fig. 9 (a) to Fig. 9. (C) is a schematic side view for explaining the combustion state.

Claims (1)

[Claims] In a premixed gas combustion burner in which a premixed gas is ejected from a large number of small holes (11) of a flame stabilizer (10) to form a combustion flame on the surface of the flame stabilizer. , The above-mentioned small holes (11) are arranged in groups (A), (B), (C)... in groups (A), (B), (C)... which are densely packed in a predetermined number on the flame stabilizer (10) with a predetermined interval between them. A premixed gas combustion burner featuring: