JPH0452410A - Burner with low generation of nitrogen oxide - Google Patents

Abstract

PURPOSE:To enable taking measures to suppress the generation of nitrogen oxides by providing in series a first blow-out section which forms a slit-shaped blow-out port in the upper section and side section and a second blow-out section which constitutes a blow-out port on the lateral side with a distance among them successively and alternately and blowing out a mixture gas of fuel gas and primary air from the second blow-out port and at the same time blowing out secondary air from the first blow-out section. CONSTITUTION:A mixture of fuel gas blown out laterally from a second blow- out section 5 and primary air mixes with secondary air blow-out from a first blow-out section 2 to become a premixture gas. At this time flames 7 are formed near the first blow-out section 2 in short flames and spread over a plane, and their heat is absorbed by a metal wall of the first blow-out section 2, and the temperature of the flames 7 is lowered and at the same time the stage of sectional mixing of the premixture gas is good because the fuel gas that is mixed beforehand and the mixed primary air and the secondary air are mixed, and the state of mixing is uniform in the direction of the length of the first and second blow-out sections 5. With this arrangement it is possible to suppress the generation of nitrogen oxides.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a low nitrogen oxide generation burner used for heating a heat exchanger of a water heater.

(Prior Art) Bunsen burners, premix burners, and the like have conventionally been used as burners for heating heat exchangers of water heaters. In the premix burner, measures are taken to prevent a local increase in flame temperature and suppress the generation of nitrogen oxides by improving the mixing state of fuel gas and air and increasing the air ratio.

(Problems to be Solved by the Invention) However, in the conventional Bunsen burner, these methods of suppressing nitrogen oxides cannot be applied, and at present, a large amount of nitrogen oxides is generated.

The present invention has been made in view of these points, namely:
Even in burners other than premix burners, measures can be taken to suppress the generation of nitrogen oxides by preventing a local increase in flame temperature, and the flame is formed in a short and planar manner, The purpose is to downsize the heat exchanger section.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the low nitrogen oxide generation burner of the present invention includes a first ejection part having a slit-like ejection hole formed across the upper part and the side part; Second jetting parts each having a jetting hole on the side are arranged alternately at intervals, and a mixture of fuel gas and primary air is jetted from the second jetting parts, and a mixture of fuel gas and primary air is spouted from the second jetting parts. The structure is such that secondary air is ejected from the ejection part.

(Function) The mixture of fuel gas and primary air jetted out laterally from the second jetting section mixes with the secondary air jetting out from the first jetting section, and becomes a premixture. At this time, the secondary air jetting out from the first jetting part has a higher flow rate and flow velocity than the air-fuel mixture jetting out from the second jetting part, so the flame is a short flame near the first jetting part. It is formed in a planar shape, and therefore the heat exchanger section using this burner can be made smaller.

As mentioned above, the short flame formed in a flat plane near the first ejection part absorbs heat by the metal wall of the first ejection part, lowering the flame temperature, and reducing the premixing described above. Since the secondary air is mixed with the pre-mixed mixture of fuel gas and primary air, the mixture state is partially good, and the length of the first and second jetting parts is The directional mixing state is also uniform, and the generation of nitrogen oxides is effectively suppressed due to these factors.

In addition, if the upper end of the first ejection part is configured above the second ejection part, lift of the flame is less likely to occur, and a high turndown ratio can be achieved.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the burner of the present invention, and FIG. 2 is a plan view.

In these figures, numeral 1 is the first ejection body, and 2 is the first ejector.
indicates the ejection part of this first ejection body 1, that is, the first ejection part 2. This first ejection part 2 forms a slit-shaped ejection hole 3 across the upper and side parts. Reference numeral 4 indicates a second ejector, and reference numeral 5 indicates an ejection part of this second ejector 4, that is, a second ejection part 5. This second spout part 5
A jet hole 6 is formed on the side. The second ejecting body 4 has a second ejecting portion 5 having a narrow width.

By alternately arranging the first ejector 1 and the second ejector 4 described above, the first ejector 2 and the second ejector 5 can be
are sequentially and alternately arranged at intervals. Moreover, the -L end of the first ejection part 2 is configured above the second ejection part 5.

In the above structure, a mixture of fuel gas and primary air is ejected from the second ejection part 5, and secondary air is ejected from the first ejection part 2. Although not shown, the second ejection body 4 ejects fuel gas into the throat part of the mixing part and sucks the surrounding air to mix it, similar to a conventional Bunsen burner, for example. A mixture of fuel gas and primary air may be ejected from the ejection part 5, and the first ejection body 1 may be configured to eject a mixture of fuel gas and primary air from the ejection part 2 using a fan or the like (not shown). It can be configured to blow out secondary air.

In the above configuration, as shown by the arrow in the figure, the mixture of fuel gas and primary air jetted out laterally from the second jetting section 5 is mixed with the secondary air jetting out from the first jetting section 2. Mix to form a premixture. At this time, since the secondary air jetting out from the first jetting part 2 has a higher flow rate and flow velocity than the air-fuel mixture jetting out from the second jetting part 5, the flame 7 is located near the first jetting part 2. The burner has a short flame and is formed in a flat shape, so the heat exchanger section using this burner can be made smaller.

As described above, the flame 7 formed in a planar manner with a short flame near the first ejection part 2 absorbs heat by the metal wall of the first ejection part 2, and the temperature of the flame 7 is lowered. The aforementioned premixture is a mixture of fuel gas and primary air that has been mixed in advance, and secondary air is mixed therein, so the partial mixing state is good, and The mixing state of No. 5 in the length direction is also uniform, and these factors suppress the generation of nitrogen oxides. In the configuration shown in the figure, the upper end of the first jetting part 2 is configured higher than the second jetting part 5, so lift of the flame 7 is less likely to occur and a high turndown ratio is achieved. be able to.

(Effects of the Invention) As described above, although the present invention is not a premix burner, it is possible to prevent a local increase in flame temperature and suppress the generation of nitrogen oxides, and to reduce the flame temperature to a short flame. Since the heat exchanger can be formed in a planar shape, it is possible to reduce the size of the heat exchanger portion.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the burner of the present invention, and FIG. 2 is a plan view. Code 1: first ejecting body, 2: first ejecting part, 3:
...Slit-shaped ejection hole, 4...Second ejector, 5...
-Second spouting part, 6...Blowout hole, 7...Flame. shi222

Claims (1)

[Scope of Claims] A first jetting part having a slit-shaped jetting hole formed across the top and sides, and a second jetting part having a jetting hole formed on the side,
They are arranged in a row alternately at intervals, and the second jetting part jets out a mixture of fuel gas and primary air, and the first jetting part jets secondary air. (2) A low nitrogen oxide generation burner characterized in that the upper end of the first ejection part according to claim 1 is configured above the second ejection part.