JPS62186123A - Combustion device - Google Patents

Abstract

PURPOSE:To restrict nitride from being generated without damaging an ignition characteristic by a method wherein several small holes larger than the other small holes are made at the portions corresponding to an ignition unit and a flame sensing unit of a burner head having many small holes therein and a metallic net is closely contacted with an other surface of the burner head. CONSTITUTION:Ignition small holes 7 have a larger cross sectional area than the other small holes 3, and flame sensing small holes 9 also have a larger cross sectional area than those of other small holes 9. A high voltage is applied to between an igniter 6 and a burner head 1, a spark discharging is carried out at the ignition small holes 7 to ignite premixed gas, resulting a spreading a flame. The premixed gas injected from the openings of the metallic net 2 may form a flame with the openings being applies as its flame ports. However, since the metallic net 2 and a burner head 1 are contacted with each other at their points, less thermal conduction is found, the metallic net 2 is heated up to its hot temperature condition to form a stable flame. In order to resistrict nitrogen oxide from being generated, a surface area of the burner head 1 is made wide, several small holes 3 are formed to decrease a density of combustion and further to decrease a flame temperatue. Flame sensing small holes 9 which are larger than the small holes 3 are made, resulting in that it is possible to get a higher electric current than that found at the other combustion portions and to facilitate a sensing of the flame.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a bar for combustion equipment.

2. Description of the Related Art Conventionally, this type of combustion apparatus has a structure in which a burner head 1 is provided with a flame hole 2 and a wire mesh is provided on the inner surface of the burner head 1, as shown in FIG. There is a structure in which a flame hole 2 is provided in the burner head 1 and a wire mesh 3 is provided on the outer surface of the burner head 1. (For example, Jikai Sho 5
8-122817, Utility Model Application Publication No. 59-18121) Problems to be Solved by the Invention However, in the above configuration, in the case of a large combustion amount, the combustion amount per unit combustion area is large. When the flame temperature is high, the nitrogen contained in the air is oxidized and becomes nitrogen oxides, which causes indoor air pollution. The problem is that when the amount of fuel gas is reduced (for example, by expanding the combustion area), the amount of fuel gas decreases and is diluted by the surrounding secondary air, making ignition extremely difficult, and detecting the ionic current in the flame. When using a flame detection means that detects the state of the flame, there is a problem that detection is extremely difficult because the flame density becomes low and the amount of ions in the flame decreases.

Means for Solving the Problems In order to solve the above-mentioned problems, the combustion device of the present invention has a burner head having a large number of small holes in the portion corresponding to the igniter and the flame detection device. It has a structure in which large small holes are provided and a wire mesh is provided in close contact with the outer surface of the burner head.

Effect According to the above configuration, the premixed gas ejected from the small hole of the burner head forms a flame at the opening of the wire mesh when the combustion amount is large, but because of poor heat conduction between the wire mesh and the burner head, the wire mesh The temperature of the flame increases, and the flame creates a stable combustion condition using the wire mesh as a flame outlet.

Therefore, even if the combustion area is expanded and the amount of combustion per unit combustion area is small, the flame can be stabilized, the flame temperature can be lowered, and the amount of nitrogen oxides produced can be reduced.

On the other hand, in the ignition part, there is a small hole that is larger than the other small holes, so the amount of fuel gas ejected is large, and the degree of dilution by the surrounding air is small, so ignition occurs by igniting the highly concentrated fuel gas. The flame formed at the ignition part spreads to the pond area. In addition, in the flame detection section, since the small holes are large, the amount of combustion per unit combustion area is large, and the amount of ions in the flame is also large, so the means for detecting the state of the flame by ion current (
Specifically, it becomes easier to apply a voltage between the burner head and the flame detector to detect the current. The ignition part and flame detection part have a higher combustion density than other parts, so the flame temperature rises and nitrogen oxides are easily generated, but the ratio of the combustion amount in the intermediate part to the total combustion amount is small, so the total The amount produced can be extremely small compared to conventional methods, making it possible to provide a combustion device that facilitates ignition and flame detection and generates fewer nitrogen oxides.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

In FIG. 1, a burner head 1 is made of a heat-resistant steel plate or the like and has a cylindrical shape with a large number of small holes 3 bored therein. Reference numeral 2 denotes a wire mesh made of heat-resistant wire, which is tightly attached to the entire outer circumference of the burner head 1. Reference numeral 4 denotes a burner cap that closes the upper closed portion of the burner head 1, and 5 indicates a vaporizing cylinder made of aluminum or the like with a heating heater cast around it, on which the burner head 1 is placed. Reference numeral 6 denotes an igniter which is insulated from the burner head 1 by an insulator 10. 7 is a small hole for ignition, and is characterized by having a larger cross-sectional area than the other small holes 3.

Reference numeral 8 is for flame detection and is insulated from the burner head 1 by an insulator 11. Reference numeral 9 denotes a small hole for flame detection, which is characterized by having a larger cross-sectional area than the other small holes 3.

In the above configuration, the fuel supplied from the fuel nozzle 12 into the inside of the vaporization cylinder 5 is heated and vaporized on the inner surface of the vaporization cylinder 5 heated by the heating heater, and becomes gaseous.
The premixed gas is mixed with the air supplied by the gas and reaches the inside of the burner head 1, and is passed through the opening of the wire mesh 2 through the small hole 3 of the burner head, the small ignition hole 7, and the small flame detection hole 9. It is discharged externally. At the time of ignition, a high voltage is applied between the igniter 6 and the burner rad 1, and a spark is discharged to the small ignition holes 7 to ignite the premixed gas, and the premixed gas is sequentially ignited through the small holes 3,
And the flame propagates to the small hole for flame detection. The premixed gas ejected from the opening of the wire mesh 2 uses the opening as a flame port to form a flame, but although the wire mesh 2 and the burner head 1 are attached closely together, microscopically they are in point contact. The wire mesh 2 has low heat conduction and is heated to a high temperature (800 to 900°C) to promote the combustion rate of the premixed gas, forming a stable flame even if the amount of combustion per unit combustion area (combustion density) is small. . This structure widens the surface area of the burner head 1 to suppress the generation of nitrogen oxides, and also provides a large number of small holes 3 to lower the combustion density and flame temperature, but at the same time, the ion density in the flame is reduced. However, according to the present invention, a small hole 9 for flame detection is provided, which has a larger cross-sectional area than other parts and has a higher combustion density, so that it is difficult to detect the ion current. By applying a voltage between 1 and 1, a larger current can be obtained compared to the combustion part of the pond, making flame detection easier. However, if small holes with a large cross-sectional area are provided in this type of combustor, the flame will adhere tightly to the wire mesh 2 when the combustion amount is reduced, which may increase the temperature of the wire mesh and impair durability.

In particular, the temperature of the wire mesh 2 located in the center of the small hole tends to rise because the heat conduction to the burner head 1 is very low. In the present invention, the shapes of the small holes for ignition and the small holes for flame detection are made into rectangular or circular shapes as shown in FIG. 3, thereby bringing the center of the small hole closer to the burner head 1, and By providing the small holes in the vicinity of the vaporization tube 5 whose temperature is lower than that of the burner head 1, heat can be transmitted to the vaporization tube 5, thereby suppressing an increase in the temperature of the wire mesh 2.

As described in detail, according to the combustion apparatus of the present invention, (1) combustion density can be reduced without impairing ignitability, and the production of nitrogen oxides can be greatly suppressed; (2) ) Stable flame detection is possible while suppressing the formation of nitrogen oxides; (3) Stable combustion can be achieved for a long period of time by suppressing the rise in temperature at the extremes of the wire mesh, with little material deterioration or deformation due to high temperatures, etc. It's something that can be effective.

[Brief explanation of drawings]

Fig. 1 is an external view of the main parts of a combustion device according to an embodiment of the present invention, Figs. 2 and 3 are external views of main parts of an embodiment of the present invention, and Figs. 4 and 5 are conventional examples. FIG. 1...burner head, 2...wire mesh, 3...
...Small hole, 6...Ignition tool, 7...Small hole for ignition, 8...Flame detection tool, 9...Small hole for flame detection. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4! Figure 5

Claims (3)

[Claims] (1) A burner head with a plurality of small holes, a wire mesh closely attached to the outer surface of the burner head, a vaporizing cylinder that heats and vaporizes the fuel and places the burner head above, and a fuel gas and a flame detector for detecting the state of the combustion flame, the burner head having a small hole larger than other small holes to which at least one of the igniter or the flame detector faces. Device. (2) The combustion device according to claim 1, wherein the small hole of the burner head facing the igniter and the flame detector is circular or rectangular. (3) The combustion device according to claim 1, wherein the small holes of the burner head facing the igniter and the flame detector are provided in the vicinity of the vaporizer cylinder.