JPH06281118A - Low nox burner - Google Patents

Abstract

PURPOSE:To perform an independent formation of a fuel rich mixing pipe and an air rich mixing pipe, combine air rich combustion with fuel rich combustion so as to restrict occurrence of NOx and stabilize an air rich flame with a fuel rich flame. CONSTITUTION:An inlet opening 13a of a fuel rich mixing pipe 13 and an inlet opening 15a of an air rich mixing pipe 15 are formed oppositely against to each other at a recess part 10a formed at a lower intermediate part. The fuel rich mixing pipe 13 and the air rich mixing pipe 15 are divided at right and left sides. An expanding plate 25 rised upwardly and expanded outwardly is connected to an upper end of a side plate 11. Combustion openings 26 are formed along both sides of an upper end combustion surface 20. Air rich mixing pipe 15 is communicating with the combustion surface 20, and the fuel rich mixing pipe 13 is communicating with a space formed by the side plate 11 and the expanding plate 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low NOx burner in which nitrogen oxide (NOx) contained in exhaust gas is reduced by incorporating it into a forced combustion gas appliance in which combustion air is blown by a fan.

[0002]

2. Description of the Related Art Recently, in gas appliances for home use such as water heaters and bath heaters, the forced combustion type has been widely used in order to reduce the size and increase the capacity, and a plurality of gas burner bodies made of steel plates are arranged side by side and burned. Configure the device. On the other hand, there is a demand for reducing NOx contained in the combustion exhaust gas of such gas appliances, and air-rich combustion in which air is excessively supplied and fuel-rich combustion in which gas is excessively supplied are combined to reduce the combustion temperature as a whole. Therefore, a means for suppressing the generation of NOx is effective. Then, various gas burners aiming to reduce NOx are provided by the combination of such rich and lean combustion.

[0003]

However, the air-rich combustion in which the primary air is excessively supplied into the mixing tube and mixed with the gas, and the lean gas is discharged from the flame hole contributes to the decrease of the combustion temperature and suppresses NOx. However, there is a problem that combustion is not stable due to flame lift. In addition, the conventional low NOx burner based on the combination of rich and lean combustion has a complicated structure and a large gas burner body. Particularly, household gas appliances are required to be downsized, and the installation space for the gas burner body is limited. Such a configuration is not preferable.

The present invention is intended to solve these problems by providing a low NOx burner having a novel structure incorporated in a forced combustion gas appliance in which combustion air is blown by a fan. Air-rich combustion and fuel rich The present invention provides a low NOx burner which suppresses the generation of NOx in combination with combustion and stabilizes an air-rich flame by a fuel-rich flame, which has a simple structure and is manufactured in a small size.

[0005]

In order to achieve the above-mentioned object, the low NOx planner of the present invention joins the edges of the bulged side plates to form a fuel-rich mixing pipe and an air-rich mixing pipe independently. Then, in the recess formed in the lower middle, the inlet opening of the fuel rich mixing pipe and the inlet opening of the air rich mixing pipe are formed opposite to each other, and the fuel rich mixing pipe and the air rich mixing pipe are distributed to the left and right and moved upward. Start up. Then, the bulging plate bulging outward is joined to the upper end of the side plate to form combustion openings along both sleeves of the combustion surface at the upper end, and the suction of the primary air is restricted in the fuel-rich mixing pipe, The air-rich mixing pipe is set so that excessive primary air is sucked, the air-rich mixing pipe is connected to the combustion surface, and the fuel-rich mixing pipe is connected to the space formed by the side plate and the bulging plate. To do. Then, the side plates are formed symmetrically with respect to the combustion surface, and the side plate is bent and manufactured at the combustion surface. The configuration of the present invention will be specifically described below with reference to the embodiments of the drawings.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of the present invention, in which a gas burner body (10) made of a steel plate is arranged in a burner case (1) at a predetermined interval and incorporated in a forced combustion gas appliance to heat a heat exchanger. It constitutes a combustion device. The fuel-rich mixing pipe (1
3) and the air-rich mixing pipe (15) are independently formed, and the recess (10a) is formed in the lower middle of the gas burner body (10).
Are formed, and the inlet opening (13a) of the fuel rich mixing pipe (13) and the inlet opening (1) of the air rich mixing pipe (15) are formed.
5a) are formed so as to face the concave portion (10a). Then, the fuel-rich mixing pipe (13) and the air-rich mixing pipe (15) communicating with the inlet openings (13a) and (15a) are erected upward in a state of being distributed right and left. Damper plates (2) and (3) having air holes that define the amount of sucked air are installed at the inlet openings (13a) and (15a) across the burner case (1), and the inlet openings (13)
The air hole of the damper plate (2) installed on the rear side of a) is set to a small diameter, and the air hole of the damper plate (3) installed on the inlet opening (15a) is set to a large diameter, and as a result, the fuel rich mixing pipe ( 13)
Suction of primary air is restricted to the air-rich mixing pipe (1
In 5), the primary air is set to be sucked in excessively. Gas nozzles (5) and (6) for ejecting fuel gas are provided on the left and right sides of the manifold (7), and both mixing pipes (13),
It is arranged so as to face (15).

A combustion surface (2) having slit holes (21) arranged in a row.
0) is formed on the upper end of the gas burner body (10), and the air-rich mixing pipe (15) is bent upward and communicates directly with the combustion surface (20). On the other hand, the fuel rich mixing pipe (13) also bends upward and extends to a height position close to the combustion surface (20), and through holes (14) are formed on both sides of the upper end.
Has been established (see Figure 3). A bulging plate (25) bulging outward is joined to an upper end portion of the side plate (11), and a combustion opening (2) opened in a groove shape along both sleeves of the combustion surface (20).
6) is formed. The bulging plate (25) is formed into a bag shape by bending the contact surface (25a) joined to the side plate (11) and the outer bulging surface (25b) and then closing the side end (FIG. 6). Upper surface (25c) which is bent at the upper end of the contact surface (25a) and contacts the bulging surface (25b), and the micro holes (27) are arranged on the upper surface (25c). Then, the contact surface (25a) is provided with an opening (28) at a position adapted to the through hole (14), and as a result, within an interval formed by the side plate (11) and the bulging plate (25). The fuel-rich mixing pipe (I3) communicates with its end. Since the bulging plate (25) is joined to the both side plates (11) by changing the direction, the two holes (28) are arranged at symmetrical positions (see FIG. 4).

The gas burner body (10) has a side plate (11) formed by swelling a single steel plate symmetrically with respect to the combustion surface (20) to form a side plate (11), which is bent at the combustion surface (20) to form an edge. The parts are folded and joined together. Then, the through hole (14) and the opening (28) are aligned with each other, and two bulging plates (25) are welded to the upper end of the side plate (11) with the combustion surface (20) interposed therebetween. It

Next, the gas burner body (10) having the above structure
The combustion will be described. When the operation switch is turned on, the valve in the gas supply path is opened, and both gas nozzles (5), (6)
Gas is discharged from both mixing tubes (13) and (15),
Combustion air is blown by the fan and the damper plate (2),
(3) defines the primary air. Then, a smaller amount of primary air than the amount of primary air suitable for the gas type is sucked into the fuel rich mixing pipe (13), the gas and the primary air are mixed in a rich gas state, and the gas is supplied to the air rich mixing pipe (15). Excessive primary air is sucked over the amount of primary air suitable for the seed, and the gas and the primary air are mixed in a lean gas state. Then, the lean gas is ejected from the slit hole (21) to perform air-rich combustion, an air-rich flame (30) is formed on the combustion surface (20), and the swelling plate (25) is ejected from the fuel-rich mixing pipe (13). The rich gas that has flowed into the inside is discharged from the fine holes (27) after being equalized and discharged, and fuel rich combustion is performed at the combustion openings (26). With the air rich flame (30) sandwiched, the fuel rich flame (32 ) Is formed (see FIG. 7). In this example, the air-rich combustion is the main combustion and the fuel-rich combustion is the sub-combustion, and the gas input ratio is set to about 7/3.

[0010]

The characteristic effects of the present invention are as follows. The low NOx burner of this invention has a combustion surface (20).
Combustion openings (26) are formed along both sleeves of the fuel cell, the air-rich mixing pipe (15) communicates with the combustion surface (20), and the fuel-rich mixing pipe (13) connects the side plate (11) and the bulging plate (25). The air-rich combustion is performed to form the air-rich flame (30) on the combustion surface (20) and the fuel-rich combustion is performed to form the fuel-rich flame at the combustion opening (26). (32) is formed. And a fuel rich mixing tube (13) formed independently
With the air-rich mixing pipe (15), air-rich combustion and fuel-rich combustion can be independently performed, and the combustion temperature can be suppressed to a low level as a whole to suppress the generation of NOx. On the other hand, the fuel rich flame (32) is formed adjacent to the air rich flame (30) so that the air rich flame (30) is formed.
The root of the slag is reinforced by the fuel rich flame (32) and takes root, so that the lift of the flame can be prevented and stable combustion can be realized.

Further, a recess (10a) formed in the lower middle part
At the inlet opening (13) of the fuel rich mixing tube (13).
a) and the inlet opening (15a) of the air-rich mixing pipe (15)
And fuel-rich mixing tube (13)
And the air-rich mixing pipe (15) are distributed to the left and right and are raised upward, so that the mixing pipes (13) and (15) are not separated from each other and do not interfere with each other and cause gas leakage. Rich combustion can be performed reliably.

Further, the edge portion of the side plate (11) is joined to form the combustion surface (20) at the upper end of the side plate (11), which is made small and thin. The low NOx burners of the present invention are arranged side by side to form a combustion device easily. It is also possible to design the installation space to be small and arrange them densely to achieve high performance, and in particular, it can be adapted to miniaturization and high performance of household gas appliances.

Further, the side plate (11) is formed symmetrically with respect to the combustion surface (20), and is bent and produced at the combustion surface (20). The side plate (11) is formed by bulging a single steel plate. Thus, it is possible to achieve a practical function such that the plate is formed without waste, and the manufacturing work is excellent in efficiency in a simple process.

[Brief description of drawings]

FIG. 1 is a front view of a gas burner body according to an embodiment of the present invention.

FIG. 2 is a plan view of a gas burner body.

FIG. 3 is a front view of a state in which side plates are joined.

FIG. 4 is a rear view of the bulging plate.

FIG. 5 is a sectional view of a bulging plate.

FIG. 6 is an enlarged plan view of a main part of a bulging plate.

FIG. 7 is a side view of the gas burner body.

[Explanation of symbols]

 10a recess 11 side plate 13 fuel rich mixing pipe 13a inlet opening 15 air rich mixing pipe 15a inlet opening 20 combustion surface 25 bulging plate 26 combustion opening

Claims (2)

[Claims] 1. A low NOx burner incorporated in a forced-combustion gas appliance for blowing combustion air by a fan, wherein a bulging side plate (11) is joined to join a fuel-rich mixing pipe (13) and an air-rich mixture. The mixing tube (15) is formed independently, and in the recess (10a) formed in the lower middle,
An inlet opening (13a) of the fuel rich mixing pipe (13) and an inlet opening (15a) of the air rich mixing pipe (15) are formed to face each other, and the fuel rich mixing pipe (13) and the air rich mixing pipe (15) are formed. Are shunted to the left and right and rise upward, and the bulging plate (25) bulging outward is joined to the upper end of the side plate (11), and the combustion opening ( 26) forming a fuel rich mixing tube (1
The suction of the primary air is restricted to 3), the primary air is sucked into the air-rich mixing pipe (15) excessively, the air-rich mixing pipe (15) is connected to the combustion surface (20), and the fuel is mixed. A low NOx burner in which a rich mixing pipe (13) is connected in a space formed by a side plate (11) and a bulging plate (25). 2. The low NOx burner according to claim 1, wherein side plates (11) are formed symmetrically with respect to the combustion surface (20) and bent at the combustion surface (20).