JPS6161004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a versatile, low cost, low NOx burner suitable for household combustion appliances.

Conventional technology Many conventional household combustion appliances use Bunsen burners, and their NOx values range from 100 to 100.
The NOx content was high at 150ppm, and there was a desire to reduce NOx in indoor open combustion appliances.

Low NOx burners such as atmospheric pressure primary burners such as sybank burners have been put into practical use for household combustion appliances, but their use was limited to stoves and the like.
The reason for this is that the production cost is high, it is difficult to secure a minimum flow rate, and the projected area of the combustion section becomes large.

On the other hand, in industrial combustion equipment, various combustion methods such as two-stage combustion have been proposed and put into practical use, but all of them involve forcibly mixing air and fuel and controlling the mixing ratio for combustion. It has the drawbacks of being too large and expensive to be applied to general household combustion appliances.

An example of a conventional burner will be explained using drawings.

In FIG. 1, reference numeral 1 denotes a combustion body, which is provided opposite to a gas nozzle and has a fuel and air suction port 2, a mixing pipe section 3, a mixture pressure equalizing section 4, and a primary flame hole section 5.
It is formed by

1 so as to cover the primary flame hole portions 5 of the plurality of combustion bodies 1.
A secondary combustion chamber 6 is provided, and a secondary flame hole 7 having a flame hole area larger than the total flame hole area of the primary flame hole portion 5 is provided on the upper surface of the secondary combustion chamber 6.
A secondary flame hole portion 8 is provided.

FIG. 2 is a cross-sectional view showing the combustion state, in which the primary flame hole 5 in the primary combustion chamber 6 is filled with only primary air.
A secondary combustion flame 9 is formed, surrounding air is supplied to the secondary flame hole portion 8, a secondary combustion flame 10 is formed in the secondary flame hole 7, and secondary combustion is performed.

In the above configuration, the gas ejected from the gas nozzle is sucked into the suction port 1 of the burner while sucking the surrounding air as primary air, and the gas is sucked into the suction port 1 of the burner.
The mixture is uniformly mixed through the mixture pressure equalization section 4, and 1
The pressure is equalized so that the ejection velocity is uniform from each primary flame hole in the secondary flame hole section 5.

The flame ignited in the secondary flame hole section 8 returns to the primary flame hole section 5 if the primary air ratio is a mixture ratio equal to or higher than the flammability limit, and a primary combustion flame 9 is formed in the primary combustion chamber 6. The primary combustion is carried out using only primary air.

Now, the primary combustion takes place on the over-combustion side, so
The fuel gas is decomposed into gases such as H ₂ , CO, and CH, and oxygen is supplied from the surrounding air at the secondary flame hole portion 8 to complete secondary combustion.

FIG. 3 shows the NOx value characteristics of the conventional Bunsen burner and the burner according to this embodiment, where curve A is the characteristic of the burner of this embodiment and curve B is the characteristic of the conventional example.

In the burner of this example, the primary air ratio starts from 80%.
The NOx value is rising because the flame temperature in primary combustion increases and the amount of NOx generated increases.

Therefore, by using the primary combustion flame 9 with a low flame temperature and a primary air ratio below the theoretical air amount,
It is possible to keep the NOx value low.

In addition, when the primary air ratio becomes low and becomes below the flammability limit, the primary combustion flame 9 is not formed in the primary combustion chamber 6 and only secondary combustion occurs, and so-called so-called combustion occurs in the secondary flame hole 7.
Since a Bunsen flame with a large NOx value will be formed, the primary air ratio will be set above the flammability limit.

Therefore, by setting the primary air ratio to an appropriate value that is above the flammability limit and below the theoretical air amount, the flame is divided into primary combustion and secondary combustion, and the flame is Low NOx combustion is achieved by smoothly transferring fire to the primary flame hole portion 5 and achieving complete combustion in the secondary combustion.

Problems to be Solved by the Invention In the conventional configuration described above, a decrease in the amount of secondary air is observed especially when the combustion amount is reduced. That is, when the combustion amount is reduced, the secondary combustion flame 10 is placed in the secondary flame hole 7.
is not formed, and a flame is formed only in the primary flame hole portion 5. However, in this state, combustion air is not sufficiently supplied into the primary combustion chamber 6.
This is because air naturally flowing in from the secondary flame hole 7 alone is insufficient. Therefore, the primary combustion flame 9 becomes elongated due to lack of air and reaches the secondary flame hole 8, resulting in a large amount of CO being generated.

An object of the present invention is to provide a burner that solves these problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides an auxiliary air port between a pair of air-fuel mixture pressure equalizing sections to facilitate the inflow of air into the primary combustion chamber. The secondary flame holes are formed into a pair of large slit shapes, and a secondary air supply path consisting of a groove for facilitating air flow is formed between the pair of secondary flame holes.

Effect With the above configuration, even when the combustion amount is reduced, air can flow into the primary combustion chamber sufficiently.
This can prevent incomplete combustion.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the same parts as in FIG. 1 shown in the conventional example are given the same numbers, and the explanation thereof will be omitted.

In FIG. 4, 11 is an auxiliary air port provided at the lower part of the primary combustion chamber 6, and 12 is a secondary air supply path provided in the secondary flame hole portion 8.

According to this embodiment, in the primary combustion chamber 6,
Primary combustion is carried out by the primary air sucked in by the gas jet from the gas nozzle and the auxiliary air supplied from the auxiliary air port 11, and the sum of the primary air amount and the auxiliary air amount exceeds the flammability limit. and if it is an appropriate value below the theoretical air amount, NOx
It is possible to keep the value low.

The secondary air supply path 12 provided in the secondary flame hole portion 8 is
It is provided to smoothly supply secondary air to the secondary combustion flame 10 formed in the secondary flame hole 7, and when a plurality of combustion bodies 1 are housed in one primary combustion chamber 6, two This has the effect of effectively supplying secondary air and improving combustion characteristics.

The reason why the secondary flame hole 7 is shaped like a large slit is that it has the effect of suppressing the temperature rise in the secondary flame hole portion 8 to a low level.

That is, since the auxiliary air port 11 is provided between the pair of air-fuel mixture pressure equalizing sections 4, it is possible to facilitate the inflow of combustion air into locations where it is difficult to inflow. In addition, a large slit-shaped secondary flame hole 7 is integrally provided, and a groove-shaped secondary air supply passage 1 is provided between the pair of secondary flame holes 7.
2, air can flow smoothly into the primary combustion chamber 6 along this secondary air supply path 12. If this secondary air supply path 12 were not present, air would flow in from around the secondary flame hole 7, but would not flow in from around the center, and the total amount of air inflow would be small, resulting in incomplete combustion. be.

Effectiveness of the Invention As described above, the present invention provides that the primary flame hole portion of each combustion body is covered with one primary combustion chamber having a secondary flame hole so that a plurality of combustion bodies perform two-stage combustion. As a result, it is possible to reduce NOx and set an arbitrary TDR, and also to smoothly transfer the flame from the secondary flame hole to the primary flame hole of each combustion body. Furthermore, the secondary air flowing into the primary combustion chamber is suppressed by the primary combustion chamber itself, making it possible to reduce NOx through two-stage combustion over the entire combustion range. Furthermore, since the primary combustion chamber has a pair of secondary flame holes, the secondary flame can be shortened. Moreover, the auxiliary air port and the secondary air supply path can eliminate the lack of air in the primary combustion chamber.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional burner, Fig. 2 is a sectional view thereof, Fig. 3 is a characteristic diagram showing NOx values of a low NOx burner and a conventional Bunsen burner, and Fig. 4 is an example of an embodiment of the present invention. It is a perspective view of the burner shown. 1... Combustion body, 4... Mixture pressure equalization section, 5... 1
Secondary flame hole section, 6... Primary combustion chamber, 7... Secondary flame hole,
8...Secondary flame hole part, 11...Auxiliary air port, 12...
...Secondary air supply path.

Claims (1)

[Claims] 1. A plurality of combustion bodies each having a primary flame hole portion consisting of an inlet portion, a mixing pipe portion, a mixture pressure equalization portion, and a plurality of primary flame holes are provided, and the primary flame hole portions of the plurality of combustion bodies are provided. 1
an auxiliary air port is provided in the primary combustion chamber located between the plurality of combustion bodies, and a pair of slit-shaped secondary flame holes are provided in the upper surface of the primary combustion chamber. and a groove-shaped secondary air supply path is provided in the primary combustion chamber between the pair of secondary flame holes.