JPH0630610U - Low NOx combustion device - Google Patents

Abstract

(57) [Summary] [Purpose] To achieve low NOx and burner durability at the same time. [Structure] A flame holding plate 5 is erected above the side surface of the burner 1 so as to surround the flame port 4. The upper end of the flame retaining plate 5 is
A heat shield portion 6 is formed by folding back a few millimeters outward along the front circumference and cutting and raising a proper portion of the flame holding plate 5.
Since the flame holding plate 5 lowers the flame temperature, the NOx emission amount is reduced and the folding back suppresses thermal strain, and the heat shield 6 prevents the upper surface of the burner 1 from locally heating.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to an improvement of a low NOx combustion device.

[0002]

[Prior art]

 Especially when exposed to a high temperature atmosphere of about 1300 ° C. or higher, the N 2 content in the air is easily oxidized and the amount of thermal NOx produced sharply increases. Therefore, various combustion devices that can reduce the amount of NOx generated have been considered for a long time, and as a typical example, as disclosed in Japanese Utility Model Laid-Open No. 60-105912, a combustion device is installed on one side of the flame mouth. A configuration in which a flame plate is erected is known.

[0003]

[Problems to be solved by the device]

 By the way, if the flame holding plate is installed upright as described above, the NOx generation amount is reduced because the flame holding plate absorbs the combustion heat and lowers the flame temperature, but the flame holding plate becomes high temperature and is thermally distorted. As a result, a problem occurs in terms of durability. Furthermore, since most of the inserts such as frame rods are provided directly above the flame mouth, the radiant heat associated with the red heat of the insert raises the temperature especially around the flame mouth in the vertical direction. As a result, there are also problems such as cracks becoming more likely to occur. The present invention has been made in view of the above problems, and an object thereof is to provide a low NOx combustion device capable of simultaneously achieving low NOx reduction and burner durability.

[0004]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a flame holding plate in which a flame holding plate is erected so as to surround a flame opening on the upper surface of a burner, and an insert such as a frame rod is arranged on the flame opening. The upper edge of the is folded outward, and the flame holding plate is cut and raised so as to cover the burner portion located below the insert, and the heat shield is formed.

[0005]

[Action]

 With such a configuration, the flame holding plate absorbs combustion heat and lowers the flame temperature, so that the amount of NO x generated is reduced, and the upper end of the flame holding plate is folded back to effectively prevent thermal strain. As a result, the radiant heat from the insert is prevented from being transmitted to the burner by the heat shield, and the durability of the burner is improved.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 to 3, in the burner 1, the mixing tube 2 and the ejection portion 3 are connected by caulking. A long flame port 4 is provided on the upper surface of the ejection portion 3, and a flame holding plate 5 is provided upright above the side surface of the burner 1 so as to surround the flame port 4. The upper end of the flame holding plate 5 is folded back to the outside by several mm over the entire circumference. In addition to the folding back, a heat shield 6 is formed by cutting and raising a proper portion of the flame holding plate 5 so as to cover a part of the upper surface of the burner 1, and the flame rod 7 and the ignition electrode 8 are formed directly above the heat shield 6. An insert is provided. In addition, 9 is a current plate, and 10 is a nozzle for ejecting fuel gas to the burner 1.

In the above-described structure, the fuel gas ejected from the nozzle 10 flows into the mixing tube 2, mixes with the primary air, then flows out from the flame port 4, and is ignited and burned by the ignition electrode 8. Since the side surface of the flame is in contact with the flame holding plate 5, the flame holding effect suppresses blow-off and the like, so that the flame burns stably. Further, since the flame holding plate 5 has an effect of absorbing combustion heat to lower the flame temperature, the NOx generation amount is reduced. It has been confirmed by experiments that this NOx is reduced by 20% or more compared to the structure without the flame holding plate 5.

The flame holding plate 5 is heated to a high temperature when it comes into contact with the flame, but the heat escapes from the flame holding plate 5 to the burner 1 and the upper end of the high temperature is folded back so that it is less likely to be distorted by heat and used for a long time. Withstand enough. Further, the frame rod 7 and the ignition electrode 8 which are directly exposed to the flame and become red heat emit a large amount of radiant heat to the surroundings thereof, but the radiant heat directed vertically downward is absorbed by the heat shield 6. Therefore, it is possible to effectively prevent the situation where the upper surface of the burner 1 is locally heated, so that cracks that cause gas leakage do not occur and safety is improved.

[0009]

[Effect of device]

 As described above, in the low NOx combustion device of the present invention, the upper edge of the flame holding plate is folded outward and the flame holding plate is cut and raised so as to cover the burner portion located below the insert. Since the heat shield is formed, it is possible to effectively prevent thermal distortion of the flame holding plate at the same time as reducing NOx, and the heat shield absorbs radiant heat from the insert that raises the temperature of the burner upper surface. Therefore, the burner is not cracked and the safety is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a low NOx combustion device of the present invention.

FIG. 2 is a sectional view illustrating a low NOx combustion device of the present invention.

[Explanation of symbols]

 1 Burner 4 Flame Mouth 5 Flame Retaining Plate 6 Heat Shield 7 Frame Rod (Insert)

Claims (1)

[Scope of utility model registration request] 1. A flame holding plate standing upright so as to surround a flame opening on the upper surface of a burner, and an insert such as a frame rod is arranged on the flame opening. The upper edge of the flame holding plate is folded back outward. At the same time, to cover the burner part located below the insert,
A low NOx combustion device characterized by cutting and raising a flame holding plate to form a heat shield.