JPS6234105Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a low NOx burner suitable for household combustion appliances, which can vary the amount of combustion, and
The purpose is to increase combustion stability.

Many conventional household combustion appliances use Bunsen burners, which have high NOx values and are not necessarily desirable for indoor open appliances.

On the other hand, a Schwank burner, which is an atmospheric pressure primary burner, is used for stoves, and low NOx has been achieved. However, the sybank burner has poor combustion characteristics with respect to changes in combustion amount and cannot achieve TDR.
Furthermore, it takes a long time to start up to reach stable combustion, combustion tends to worsen due to the influence of air currents, etc., and because it is all primary combustion, it is easy to cause backfire, so it is necessary to make the flame hole small. ,
The drawback was that the combustion load could not be increased. Therefore, it has been difficult to apply it to appliances other than stoves.

The present invention solves the above-mentioned drawbacks by dividing the Bunsen burner into primary combustion and secondary combustion.
This is to improve the heat resistance of the flame hole where the secondary combustion takes place.

Below, one implementation of the present invention is shown in Figures 1 and 2.
This will be explained based on the diagram.

FIG. 1 is a diagram showing the principle of construction of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1.

In the figure, 1 is a Bunsen burner, and together with the fuel ejected from the gas nozzle 2, there is a suction port 3 that sucks the surrounding air as primary air, a mixing pipe 4, a mixture pressure equalizing part 5,
It is composed of a primary flame hole section 6 having a plurality of slit-shaped flame holes. Primary flame hole part 6 of Bunsen burner 1
The primary combustion chamber 7 provided so as to cover the combustion chamber 7 is integrally molded from a sheet metal, and a ceramic plate 10 is inserted into the upper part thereof with a sealing material 8 interposed therebetween. As is clear from FIGS. 1 and 2, this ceramic plate 10 has one opening in the center with a short diameter of 5 mm or more and a flame hole area larger than the total flame hole area of the primary flame hole section 6. This is used as the secondary flame hole 9. 11
is the primary combustion flame that burns in the primary combustion chamber, and 1
2 is a secondary combustion flame that burns in the secondary flame hole 9.

In the above configuration, the fuel injected from the gas nozzle 2 to the suction port 3 of the Bunsen burner 1 sucks the surrounding air as primary air, and is mixed almost uniformly through the mixing pipe 4 and the mixture pressure equalizing section 5. , is ejected from the primary flame hole portion 6, primary combustion is performed in the primary combustion chamber 7 using only primary air, and a primary combustion flame 11 is formed in the primary flame hole portion 6. The primary combustion is performed almost exclusively with primary air, and since the amount of primary air is set to be above the flammability limit and below the theoretical air amount, combustion occurs in an oxygen-deficient state.

That is, since the primary combustion in the primary combustion chamber 7 is performed with less than the theoretical air amount, the combustion is not completely completed, and the surrounding air is supplied as secondary air through the secondary flame hole 9 and the secondary combustion is carried out. Combustion takes place.

Now, if you want to vary the combustion amount, you can adjust the fuel injection pressure with a governor etc. to obtain the combustion amount according to the pressure, and the combustion amount can be changed within the range where the primary air suction amount is above the flammable limit. range.

In addition, the secondary burner hole 9 has a minor axis of 5 mm or more and a burner hole area equal to or larger than the total burner hole area of the primary burner hole section 6.
Care is taken to ensure that the primary combustion chamber 7 and secondary flame holes 9 do not provide significant resistance to the intake of secondary air.

Therefore, since the combustion is divided into primary and secondary combustion, the flame temperature in the combustion zone is lower, and the primary combustion is performed with less than the theoretical amount of air, so the amount of oxygen is small, so it cannot be used with a conventional Bunsen burner. low in comparison
The amount of NOx can be reduced to 1/2 or less.

Furthermore, the secondary flame hole 9 is made of a ceramic plate 10.
Although it has a large heat capacity, it is heated by the primary combustion flame 11 and reaches a high temperature in a short time, resulting in stable combustion. Although the secondary flame hole 9 becomes high temperature,
Since it is inserted into the primary combustion chamber 7 integrally formed of sheet metal through the sealing material 8, it is possible to prevent abnormal noises generated at metal joints due to thermal stress when igniting or extinguishing a fire. Furthermore, 9 parts of secondary flame holes are 700 ~
Ceramic plate 1 reaches high temperatures of around 800℃.
Since it is 0, it is sufficiently heat resistant.

In addition, the primary combustion in the primary combustion chamber 7 is not carried out using only primary air, but auxiliary air is supplied into the primary combustion chamber 7, so that the sum of the primary air and the auxiliary air exceeds the flammability limit or theoretical air. Almost the same effect can be obtained if the amount is less than that amount.

As is clear from the above explanation, according to the present invention, since the Bunsen burner is divided into primary combustion and secondary combustion, and a ceramic plate is used for the secondary flame hole, low NOx combustion is achieved. We can provide a low NOx burner that provides stable combustion with quick start-up and is also compatible with TDR.

In addition, since the primary combustion chamber is a single chamber that is not divided into many sections, it is possible to smoothly transfer the flame to each primary flame hole without causing explosive ignition, and also to ensure that the flame touches the partition wall during the primary combustion. Since this does not occur, CO emissions can be reduced.

Furthermore, since the secondary flame hole is formed with a ceramic plate, there is no problem even if it is heated by both the primary and secondary combustion flames, and since there are no many partition walls in the primary combustion chamber, distortion caused by these walls can be avoided. No such occurrences occurred.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of the low NOx burner of the present invention, and FIG. 2 is a sectional view taken along line A-A in FIG. 1...Bunsen burner, 6...Primary flame hole, 7
...Primary combustion chamber, 9...Secondary flame hole, 10...Ceramic plate.

Claims (1)

[Scope of utility model registration request] A primary combustion chamber integrally formed of sheet metal is provided to cover the primary flame hole portion consisting of a large number of flame holes of the Bunsen burner, and a ceramic plate is provided above the primary combustion chamber. A burner in which an opening larger than the total flame hole area of the primary flame hole is formed in a ceramic plate, and this opening is used as a secondary flame hole.