JPH09159119A - Gas burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of NOX and to make it possible to stably burn with a high load by providing a recess at the upper surface of a burner body, perforating a plurality of burner ports on the wall surface in the recess, and injecting premixed gas mixed with the air of a specific ratio or less with respect to the theoretical combustion air quantity from the burner port. SOLUTION: A recess 3 is provided on the upper surface of a burner body 1 above which a material to be heated is disposed. A plurality of burner ports 4 are perforated on the wall surface in the recess 3, and premixed gas mixed with the air amount near the theoretical value (within ±30% of theoretical air amount) to the low pressure gas (300mmHg2 O or less) such as city gas is injected from the port 4. Accordingly, since the secondary air is hardly supplied to the space between the recess 3 or the upper surface 2 of the burner body 1 and a material to be heated during burning, the combustion is completed without supplying the air more than necessary but sufficient for the combustion to the flame. Therefore, the generation of NOX due to the excess supply of oxygen is suppressed to make it possible to stably burn at a high load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a Bunsen type low pressure gas burner used for a gas stove, a water heater, or the like.

[0002]

2. Description of the Related Art Generally, in this type of burner, a large-capacity burner, which is often used for business purposes, has a large flame length. Therefore, in a ring burner having a main flame hole on the outer peripheral surface, the diameter of the pot bottom is relatively large. Has a problem that the maximum temperature part of the flame goes out to the outside of the bottom of the pot and the heat efficiency decreases. Being developed. FIG. 6 shows an example of the structure, in which a large number of vertical slit-shaped flame holes 4 are provided on the inner peripheral surface of the horizontal ring-shaped burner head 1, and the flame is jetted inward, which is once Since it folds back just below the center of the bottom surface of the heated container A and reaches the outer peripheral edge thereof, the contact time between the flame and the bottom of the pot increases and the thermal efficiency improves.

[0003]

In the above-mentioned inward flame burner, when the primary air amount is increased and the flame length is shortened in order to further improve the thermal efficiency, the maximum temperature point of the flame is within the radius of the pot bottom. In addition to the advantage that the flame that impacts the bottom of the pot becomes stronger and the heat transfer rate from the flame to the bottom of the pot is improved, the combustion temperature becomes higher
There is a drawback that the x generation amount increases. However, it cannot be said that all burners with high flame temperatures also have a high NOx generation rate, and it is considered that the excessively supplied secondary air also greatly contributes to the NOx generation rate. In view of the above problems, it is an object of the present invention to provide a structure of an inward-flame burner with low NOx and high thermal efficiency by cutting off the supply of excessive secondary air.

[0004]

As shown in FIGS. 1 and 2, the present invention is directed to a burner body 1 on which an object A to be heated is arranged.
A recess 3 is provided on the upper surface 2 of the plate, and a plurality of flame holes 4 are formed in the wall surface of the recess 3, and the amount of air from the flame holes 4 to the low pressure gas (300 mmH2O or less) such as city gas is close to the theoretical value. A premixed gas mixed with (within ± 30% of the theoretical air amount) is ejected. During combustion, between the recess 3 or the front surface 2 of the burner body 1 and the object A to be heated, Since the secondary air is hardly supplied to the space, the combustion is completed without supplying more than the air amount necessary for combustion to the flame, which suppresses the generation of NOx due to the excessive supply of oxygen. Therefore, a gas burner with high load and low NOx can be realized.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which a large number of vertical slit-shaped flame holes 4 are provided in the upper part of the inner peripheral wall of a main body 1 of a ring burner over the entire circumference. In the inward flame type gas burner having the above structure, below the flame hole 3,
The burner body 1 is provided with a shield plate 5 that closes the blow-through space B in the center of the burner to form a recess 3 in the center of the burner body 1. In this embodiment, since it is necessary to secure a sufficient flame hole area on the narrow inner peripheral surface, the flame hole 4 is formed in a vertical slit shape, but of course, it may be formed by a plurality of round hole-shaped flame holes. Good. Reference numeral 6 is a mixing pipe, and 7 is an ejector nozzle, which sucks primary air from the surroundings at a fuel gas ejection speed to perform premixing.

In the conventional ring burner, since the secondary air is abundantly supplied through the blow-through space B in the center of the horizontal ring-shaped main body 1, this secondary air is supplied to the flame more than the theoretical combustion air amount and NOx is generated. One of the causes is that the central blow-through space B is closed as in the present embodiment and a gas in which almost all theoretical combustion air is mixed in advance is supplied to the flame hole 4 to supply excess oxygen. This prevents the generation of NOx due to the supply of NOx.

FIG. 2 shows another embodiment of the present invention, in which a large number of flames are provided over the entire length above the opposite surfaces of two straight tubular burner bodies 1 arranged horizontally and in parallel. Along with the hole 4, a shield plate 5 for closing the blow-through space B in the center of the burner is provided below the lower end of the flame hole 4, and this space B
Is a recess 3. FIG. 3 shows still another embodiment of the present invention, in which a plurality of the recesses 3 are provided in the upper surface 2 of the burner body 1 and a plurality of flame holes 4 are provided in each recess 3. In addition, FIG. 4 shows that the inner peripheral surface of the outer ring 1a and the outer peripheral surface of the inner ring 1b of the double ring burner are provided with flame holes 4 so as to face each other, and both the rings 1a and 1b.
The lower part of the space B between them is closed to form the recessed portion 3. Further, FIG. 5 shows that the flame holes 4 are provided only on the inner wall surface in the annular recessed portion 3. In any case, even though the primary air amount is increased and the flame ejection speed is increased compared to the conventional method, the recess 3 acts as a flame holding mechanism, so that the flame is not lifted and stable. Can perform high-load combustion.

[0008]

As described above, the gas burner according to the present invention is designed such that the premixed gas is ejected from the flame holes 4 provided on the wall surface in the recess 3, so that the secondary gas is injected into the recess 3. The burner body 1 is not supplied with air and is burning.
Since the secondary air is hardly supplied to the space between the upper surface 2 of the base plate and the object A to be heated, the air is not supplied to the flame in an amount more than the amount of air necessary for combustion. Has the advantage of suppressing the generation of NOx due to excessive supply, and even if all the premixed gas is supplied to the Bunsen burner, the recess 3 acts as a flame holding mechanism, so there is no risk of flame lifting. Therefore, there is an advantage that high-load combustion can be stably performed.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of an essential part of an embodiment of the present invention.

FIG. 2 is a perspective cutaway view of an essential part of another embodiment of the present invention.

FIG. 3 is a perspective view of still another embodiment of the present invention.

FIG. 4 is a perspective view of yet another embodiment of the present invention.

FIG. 5 is a perspective view of yet another embodiment of the present invention.

FIG. 6 is a sectional view of a conventional example.

[Explanation of symbols]

 1 Burner body 2 Upper surface 3 Recess 4 Flame hole 5 Shielding plate 6 Mixing pipe 7 Ejector nozzle A Heated object B Blow-through space

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuji Abe, 4-1-2, Hirano-cho, Chuo-ku, Osaka, Osaka Gas Co., Ltd. (72) Masafumi Matsubara, 507-2 Shinhocho, Tokai-shi Toho Gas Co., Ltd.

Claims (3)

[Claims] 1. In a low-pressure Bunsen burner, a recess is provided in the upper surface of the burner body, and a plurality of flame holes are formed in the wall surface of the recess, and the theoretical combustion air amount is ± 30 from the flame hole.
The gas burner is characterized in that a premixed gas mixed with air within 100% is ejected. 2. An inner peripheral wall of the ring burner is provided with a flame hole over the entire circumference, and below the flame hole, a shield plate for closing a blow-through space at the center of the burner body is provided. The gas burner according to claim 1. 3. Flame holes are arranged in a row over substantially the entire length on opposite surfaces of a straight tubular burner body arranged horizontally and in parallel, and a blow-through between both burner bodies is provided below the flame hole. The gas burner according to claim 1, further comprising a shielding plate that closes the space.