JPS60152809A - Burner - Google Patents

Abstract

PURPOSE:To improve a throttling characteristic of the flame in a burner for an indoor open- type combustion equipment such as a household-use heating equipment and a hot water heater by a method wherein it has a double flame hole structure having a specified clearance between the two. CONSTITUTION:A convex metallic net 9 is arranged at a mixing gas supplying part with a certain clearance being left against a burner body 8 having several flame holes 7. An area of flame holes 7 in the burner body 8 is made smaller than that of the flame holes opened in the metallic net 9, and the burner body 8 is made of a material such as zirconia and cordierite which can be ignited with catalyst. The fuel injected from the nozzle 6 is injected as mixing gas from the flame holes 7 of the burner body 8 in such a way as air is sucked through the primary air hole 4 under an injecting pressure of the fuel and passed through the metallic net 9. Upon ignition of the mixing gas, hot catalyst combustion is carried out at the burner body 8 where the flame holes 7 are contacted with the mixing gas. Then, as an amount of combustion at the nozzle 6 is gradually decreased, resulting in that a degree of red heating of the burner body 8 is reduced. In turn, it becomes possible to make a combustion in a wider flame hole area than the flame holes 7 of the metallic net 9, the combustion is transmitted to the metallic net 9 at the mixing gas, while a throttling of CO down to about 20%, with burning amount down to 20% are enabled, resulting in improving TDR.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention is applicable to indoor open combustion equipment such as household heaters (fan heaters) and water heaters (instantaneous water heaters) that have low NOx and require a combustion meter throttle. Regarding burners.

Conventional structure and its problems Conventionally, as shown in FIG. 1, the burner body 1 is made of ceramic and has a large number of circular flame holes 2, and a burner case having a mixing tube 3 and a primary air hole 4. 5 constitutes a burner unit. 6 indicates a fuel supply nozzle. FIG. 2 shows an example in which the burner body 1 and the flame hole 2 are made of gold steel. In this configuration, air is sucked in from the primary air hole 4 by the pressure of the fuel ejected from the nozzle lv6, and is guided to the flame hole 2 as a mixture to form a flame. Generally, this type of burner is configured to burn in a region close to the stoichiometric air amount and completely premixed. Therefore, the flame is short and the combustion reaction time is short, so NOx is low. But Tuyn Dow
n, Ratio (hereinafter referred to as TDR), that is, the drawability is poor, and as shown by the curve in FIG. In the case of the flame hole made of ceramic material as shown in Fig. 1, the squeezing property is a little worse and CO increases by 70 to 80%. This means that the flame hole area is N
Larger flame hole area than conventional Bunsen combustion with a large amount of Ox [IJ
The flame hole load is 0.2 to 0.3 hr, and the flame is held and burned by the red heat of the material of the burner body 1, so when the combustion amount is reduced, the burner body 1 Since the burner body 1 is not red-hot due to lack of heat capacity to generate red heat, the flame holding effect is lost and the conventional low NOx burner cannot achieve TDR.Purpose of the Invention The present invention is a low NOx lv: The purpose is to make it JT D R and to make it more compact.

Structure of the Invention In order to achieve this object, the present invention has a double flame hole structure with a certain gap, and the flame hole area on the mixture side is made larger than the flame hole area on the combustion exhaust gas side. The burner body constituting the flame hole on the combustion exhaust gas side is made of a material that has a catalytic effect, such as zirconia or copillite.

DESCRIPTION OF EMBODIMENTS FIG. 3 shows an embodiment of the present invention. 1st. Parts common to FIG. 2 are designated by the same numbers. A burner body 8 having a large number of flame holes 7 and a convex metal steel 9 with a certain gap are provided on the air-fuel mixture side, and the burner body 8 and the metal steel 9 are fixed with a burner box body 10, and the burner case 5 and connected. The flame hole area of the flame hole 7 of the burner body 8 is configured to be smaller than the flame hole area where the open part of the metal screen 19 is the flame hole. The burner body 8 is made of a material capable of catalytic combustion, such as zirconia or copillite.

In this configuration, the fuel ejected from the nozzle/I/6 is
Due to the ejection pressure of the fuel, air is sucked through the secondary air hole 4, passes through the steel 9, and is ejected from the flame hole 7 of the burner body 8 as a mixture. By igniting this air-fuel mixture, high-temperature catalytic combustion occurs in the flame hole 7 and the burner body 8 with which the air-fuel mixture comes into contact. Zirconia, copillite, etc. are 800 to 1
The catalytic reaction is activated at 200'C, and if the temperature is within 1200°C, NOx is kept low to 5 ppm or less, which is 0.4 to 0.6 Vt, which is twice as much as normal gold-copper combustion. mA h r
1 = Burning at the flame hole loading rate.

Next, if you take TDR and gradually reduce the amount of combustion from the nozzle/I/6, the degree to which the burner body 8 becomes red hot will decrease, but the flame hole area is wider than the flame hole 7 of Kinko 9. It becomes possible,
The combustion shifted to the gold steel 9 on the air-fuel mixture side, and as shown in Figure 5B, CO did not increase until the amount of combustion reached approximately 20%, and the strangibility was 20%.
%, and TDFt improves. That is, the burner body 8 and the flame hole 7 on the combustion exhaust gas side perform catalytic combustion up to the 50 ratio throttle, and the combustion is performed with the steel 9 from 50% to 20 ratio, thereby improving the TDR1 yield.

FIG. 4 shows another embodiment, which has a cylindrical double flame hole configuration, with a burner body 11 made of copierite, zirconia, etc., having a large number of flame holes 12, and a gap inside the burner body 11. It is made of gilt copper 13 and has a double flame hole configuration, and burns in a cylindrical shape rather than a flat surface.The function is the same as above, so the explanation will be omitted. - Complete premixing of the secondary air is 1 iJ, but if complete premixing cannot be achieved with only the nozzle 6, it is also possible to increase the amount of air by installing a power source such as a fan.

Therefore, as the flame holes on the air-fuel mixture side, a Schwunk-type burner body having a large number of flame holes in a ceramic body with low NOx may be used.

Effects of the Invention The area of the flame hole on the mixture side is made larger than the area of the flame hole on the combustion exhaust gas side, and the burner body that constitutes the flame hole on the combustion exhaust gas side is made of a material that has an effect on catalysis, such as zirconia or copillite. As a result, it is possible to provide a burner with low NOx and high TDR, and the convenience of clean combustion and energy-saving capacity control for indoor open space heaters and water heaters is greatly improved. Moreover, when the combustion amount is reduced by taking TDR, the flame hole area on the air-fuel mixture side can be made into a compact combustion part with a small projected area because it matches the area of the flame hole on the fuel-air mixture side to the conventional gold-bronze burner and Schvanck burner.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of conventional low NOx burners, and Figure 3 is a cross-sectional view of a conventional low NOx burner.
4 is a sectional view showing an embodiment of the burner of the present invention, and FIG. 5 is a characteristic diagram of IN-Put% and CO/CO2. 7...flame hole, 8...burner body, 9...
Gold steel. Name of agent: Patent attorney Toshio Nakao and 1 other person
Figure 5 of page 1 shows the amount of combustion

Claims (1)

[Claims] In a configuration in which a mixture of fuel and air is supplied and burned in a flame hole, a double flame hole configuration is used with a certain gap, and the flame hole area on the mixture side is larger than the flame hole area on the combustion exhaust gas side. ,
A burner that opens the flame hole on the combustion exhaust gas side (a burner made of a material with a catalytic action such as zirconia or copillite).