JPS5912230A - Burner - Google Patents

Abstract

PURPOSE:To contrive much more reduction of NOX, by providing a flame detecting part with a partition plate within a primary burning chamber whose burning flame is divided into a primary burning and a secondary burning, and a flame rod an auxiliary air opening are provided in the detecting part. CONSTITUTION:A primary burning chamber 7 is provided so as to cover a primary flame hole part 6 of a burning body 1 and a flame detecting part 17 is provided within the burning chamber 7 by dividing it with a partition plate 16 provided with an opening 15 for transferring fire. A flame rod 9 is provided in a primary burning 10 of the detecting part 17 and an auxiliary air opening 14 is provided as well. In addition to the above, a control circuit 12 controlling a fuel feed control valve 13 and burning by obtaining a detecting signal of an ionic current by the rod 9 is provided. With this construction, the ionic current is detected under a stable state and a reduction of NOX of auxiliary air without affecting a whole area of the burning chamber 7 and thereby obtaing an improved stability of a flame.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to the field of improving clean combustion and safety of household combustion appliances.

Conventional configurations and their problems Since most conventional home combustion appliances use Bunsen burners, their NOx values are as high as 100 to 150 PPm, and it is desirable to reduce NOx in indoor open combustion appliances. It is rare.

Low NOx burners such as atmospheric-pressure full-order burners such as Schwank burners for household combustion appliances have been put into practical use, but they have drawbacks such as high production costs, difficulty in achieving TDR, and a large projected area of the combustion part. Therefore, its use was limited to stoves, etc.

Furthermore, in household open-type combustion appliances, there is a demand for safety devices that detect incomplete combustion due to a drop in oxygen concentration or clogging of the primary air port, etc. A lift-up method using a flame rod, a detection method using an ion current in a flame rod, etc. have been proposed, but these methods have problems such as reaching the detection level after reaching an incomplete combustion state depending on the type of gas. was.

On the other hand, as shown in Japanese Patent Application No. 55-72298 shown in Fig. 5, the Bunsen burner is divided into primary combustion and secondary combustion to reduce NOx.
In addition, all primary combustion flames are detected 3'.

A combustion device has been proposed that detects incomplete combustion by - and the NOx level increases, and if auxiliary air is not introduced, the ionic current becomes small due to variations in the amount of primary air sucked in, making malfunctions more likely.

OBJECTS OF THE INVENTION The present invention aims to improve the above-mentioned drawbacks, reliably detect incomplete combustion, and further reduce NOx.

Structure of the Invention The present invention divides the combustion flame of a Bunsen burner into primary combustion and secondary combustion to reduce NOx, supplies auxiliary air to the primary combustion flame, and detects the combustion state by detecting ion current. In addition, a partition plate is provided in the primary combustion chamber to prevent the auxiliary air from affecting the entire primary combustion area, thereby further reducing NOx.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In FIG. 1, reference numeral 1 denotes a combustion body, which is provided with a fuel and air suction port 3 facing a gas nozzle 2. Mixing pipe section 4. Mixture pressure equalization section 5. It is formed by a primary flame hole section 6 consisting of a plurality of slit-shaped primary flame holes.

Now, a primary combustion chamber 7 is provided so as to cover the primary flame hole part 6 of the combustion body 1, and a part of the primary combustion chamber 7 has both ends with a flame hole area larger than the total flame hole area of the primary flame hole part 6. A single secondary flame hole 8 is provided, the width of which is smaller than that of the medium flame part. 1, a primary combustion flame 1o formed only by primary air is formed in the primary flame hole 6 in the combustion chamber 7, and a flame is formed in the primary combustion flame 1o! 9 is provided. Ambient air is supplied to the secondary flame hole 8.
A secondary combustion flame 11 is formed.

Reference numeral 12 denotes a control circuit consisting of a detection object that detects the ion current of the flame rod and a control section that controls combustion in association with the detection section; 13 a valve that controls fuel supply in association with the control circuit 12; It is.

14 is a partition plate 16 having a flame transfer opening 15; 14 is an auxiliary air port provided in a flame detection unit 17 provided at the end of the combustion chamber γ; and a frame rod provided in the flame detection unit 17; It is provided at the lower part of the primary combustion chamber 7 near the combustion chamber 9.

FIG. 3 is a sectional view taken along the line AA in FIG. 1, showing the state of the flame.

2, the gas ejected from the gas noise 2 is sucked into the suction port 3 of the burner while sucking the surrounding air as primary air, passes through the mixing pipe 4 and the mixture pressure equalization part 6, and is uniformly and the pressure is equalized so as to have a uniform jetting speed from each primary flame hole of the primary flame hole section 6.

The flame ignited in the secondary flame hole 8 returns to the primary flame hole part 6 if the primary air ratio is below the flammable limit, and the primary combustion flame 1o is generated in the primary combustion chamber γ. formed.

Primary combustion is performed using only primary air.

In the flame detection section 1A, which is divided by a partition plate 16 provided in the primary combustion chamber 7, primary combustion is performed in the primary air and the auxiliary air.

Now, since the primary combustion is performed on the fuel-excess side, the fuel gas is decomposed into gases such as H2, Go, and CH, and oxygen is supplied from the surrounding air at the secondary flame hole 8 to complete the secondary combustion.

FIG. 4 shows Co1002 characteristics, flame impedance characteristics, and flame impedance characteristics depending on atmospheric oxygen concentration of the combustion apparatus according to the present invention.
The curve A shows the CO/C02 characteristic, the curve B shows the flame impedance characteristic of the primary combustion flame, the curve C shows the NOx value characteristic, and the curve B' shows the conventional flame without auxiliary air. Impedance characteristics, curve C'
shows the NOx characteristics when auxiliary air is introduced in the conventional example.

That is, the NOx value can be kept low by dividing the combustion into primary combustion and secondary combustion to lower the overall combustion temperature, and by burning the primary combustion flame 10 with an amount of primary air that is lower than the theoretical air amount with a low flame temperature. In particular, by providing the partition plate 16 within the primary combustion chamber 7, low NOx can be achieved without the auxiliary air affecting the entire primary air area.

Note that when the primary air ratio becomes low and becomes below the flammable limit, the primary combustion flame 10 is not formed in the chamber 7 and only secondary combustion occurs, and the secondary combustion hole 8 burns buszene with a high NOx value. Since combustion takes place, the primary air ratio is set at -I- below the flammability limit.

When the oxygen concentration in the atmosphere decreases to about 18% to 19%,
Since the amount of primary air in the primary combustion flame 10 is below the flammability limit, no flame is formed and the process shifts to secondary combustion, but since the auxiliary air port 14 is provided near the flame rod 9, the primary combustion The transition to secondary combustion occurs only after the oxygen concentration becomes even lower, and at that time the flame impedance changes from several tens of OKΩ to several MΩ to infinity.
Even after transitioning to the next combustion stage, the combustion continues with a so-called Bunsen flame, so the rise of GO//C02 is caused by an even lower oxygen concentration (02 ÷
15%). At this time, the width of the single secondary flame hole is shorter than that of the medium flame part at both ends, so
Increases flame stability at both ends of the flame hole.

Further, as the 02 concentration decreases, the flame temperatures of the primary combustion flame 10° and the secondary combustion flame 11 decrease, so the NOx value tends to decrease.

On the other hand, if the primary air port is clogged, the amount of primary air (Pa) sucked decreases, and when the amount of primary air falls below the flammable limit, the primary combustion flame 10 rises and only secondary combustion occurs. At this time as well, the frame impedance ld changes from several 10 OKΩ to several MΩ to infinity.

CO//C02 rises only after the primary air suction amount has further decreased, and the NOx value rises after the primary air intake amount has completely shifted to secondary combustion.

Hereinafter, in FIGS. 2 and 4, the flame impedance is expressed, which shows a certain relationship with changes in the ion current.

Effects of the Invention - As explained above, according to this embodiment, the flame detection section 17 is provided in the primary combustion chamber 7 with the partition plate 16, the frame rod 9 is provided therein, and the auxiliary air port 14 is provided therein. As a result, the ion current can be detected in a stable state without malfunction, and even if auxiliary air is introduced into the primary combustion chamber 7, it is only effective for the primary combustion in the flame detection section 17, and the entire area of the primary combustion chamber 7 is Low NOx combustion with no impact is achieved. 2 more
By making the width of both ends of the flame hole shorter than that of the center, the stability of the flame is increased when the atmospheric oxygen concentration decreases.

Therefore, according to the present invention, in a Bunsen burner provided with a primary combustion chamber and divided into primary combustion and secondary combustion,
By providing a flame detection section with a partition plate in the next combustion chamber, and providing a flame rod and auxiliary air port there, it is possible to provide a low NOx combustion burner with less influence from auxiliary air.
A highly safe device that can detect a drop in atmospheric oxygen concentration due to insufficient ventilation and incomplete combustion due to clogging of primary air holes before reaching the incomplete combustion state, and control combustion in a stable state without malfunction. It is possible to provide the following.

Furthermore, since the flame detection section is provided separately within the primary combustion chamber, it is possible to set the primary combustion using the primary air to the conditions that result in the lowest NOx, resulting in further reductions in NOx. .

10 pages

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of an embodiment of the combustion apparatus of the present invention, FIG. 2 is a perspective view of an embodiment of the present invention, and FIG. 3 is a sectional view taken along line A-A in FIG. FIG. 4 is a characteristic diagram of the combustion apparatus of the present invention, and FIG. 5 is a partially sectional side view of the conventional combustion apparatus. 6...Primary flame hole part, 7. River...Primary combustion chamber, 8
...Secondary flame hole, 9...Frame rod, 12...Surface control circuit, 14...Auxiliary air port,
15... Fire transfer opening, 16... Partition plate, 17... Flame detection section. Name of agent: Patent attorney Toshio Nakao Haga 1 person No. 4
Figure 3 Figure 2 Figure 5

Claims (1)

[Scope of Claims] A primary combustion chamber having a plurality of primary flame holes covering a primary flame hole portion is provided, and a secondary flame hole is provided in the primary combustion chamber for fire transfer. A partition plate with an opening is installed, a flame detection section is installed, and
A control circuit is provided in which a flame rod is provided in a position facing the primary flame hole in the flame detection section, an auxiliary air port is provided in the flame detection section, and the ionic current flowing through the flame rod is detected and combustion is controlled. Combustion device with.