JPH07117201B2 - Combustion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a combustion device for reducing the concentration of nitrogen oxides contained in combustion gas.

(Prior Art) Many household heaters include a combustor that directly discharges combustion gas into a room because it is easy to handle and move, such as an oil portable stove. In particular, an oil fan heater or a gas fan heater that vaporizes liquid fuel or burns it in a spray state consumes a relatively large amount of fuel, and a large amount of combustion gas is exhausted indoors. These combustors harmful to other materials and unburned gases such as causing odor CO and THC, .NO _x also discharged like generated nitrogen oxides (NO _x with the hot combustion reaction , .NO _x even traces on a large adverse effect on the human body, the difference in the generation mechanism, thermal (thermal) NO _x and Fuyuru (fue
l) It can be divided into NO _x . When the fuel is light oil such as kerosene or a gas that does not contain nitrogen, the latter can be ignored and the former generation of thermal NO _x becomes a big problem. In particular, oil or gas fan heaters, which have a relatively high flame temperature and consume a large amount of fuel, are a thermal NO
The concentration of _x generated is high, and it is important to take measures to suppress the generation thereof as much as possible.

Therefore, conventionally, as measures for reducing NO _x in this type of combustor, reduction of flame temperature, reduction of residence time required for fuel gas to pass through a combustion region, and the like have been considered. In order to reduce the flame temperature, for example, a method is used in which a cooling body that is red-heated by the flame and cools the flame by radiation is placed in the flame. Further, in order to lower the flame temperature and shorten the residence time, methods such as subdividing the flame mouth are adopted. Among these, the method of placing the cooling body in the flame, particularly the method of placing the cooling body in the high temperature portion upstream of the flame, has a large effect of reducing NO _x because it directly lowers the flame temperature.

However, as mentioned above, placing the cooling body in the flame,
The following problems have been encountered even in a combustion apparatus that employs a system in which a cooling body is red-heated by a flame and the flame temperature is lowered by radiation from the cooling body.

That is, in order for the cooling body to exert a good flame temperature lowering function, it is necessary to use a large cooling body having a large surface area and dispose this cooling body at a high temperature portion upstream of the flame, that is, at a location near the flame mouth. There is. However, when such a large cooling body is arranged in the above relationship, there is a problem that the combustion state is deteriorated because the flow of the combustion gas is blocked by the cooling body.

Further, in the case of a fan heater or the like, a flame rod for detecting a combustion state by a flame current value and a spark rod which is an igniter are provided in a flame upstream portion near a flame mouth of a burner. Therefore, if the cooling body is brought too close to the burner flame port, not only the inconvenience that the flame current value during weak combustion decreases and sparks fly to the cooling body leading to poor ignition, but the flame temperature is required during weak combustion There is also a problem in that the flame current value decreases due to the above decrease.

(Problems to be Solved by the Invention) As described above, the conventional fan heater has a problem that it is not possible to arrange the cooling body for NO _x reduction sufficiently close to the burner flame port.

The present invention has been made in view of the above points, and brings about a large NO _x reduction effect by bringing the cooling body close to the burner flame port without causing a decrease in flame current value or poor ignition during weak combustion. An object is to provide a combustion device.

[Structure of the Invention] (Means for Solving Problems) In the combustion apparatus according to the present invention, a flame rod for detecting a combustion state and a spark rod for ignition are provided on the flame mouth of the burner so as to project therefrom. A cooling body for lowering the flame temperature by radiation is provided so as to be positioned in the flame formed above, and the cooling body is a cooling body main body on the downstream side of the flame and a flame mouth side from this main body. The cooling fin is thinner than the main body and extends.

(Operation) As described above, the cooling body includes the cooling body main body arranged on the downstream side of the flame, and the cooling fins formed thinner than the cooling body main body and extending from the cooling body main body toward the flame mouth side. Therefore, the upstream side of the flame comes into contact with the thin cooling fins. Therefore, since the cooling fins are thin, the flow of the combustion gas is not hindered and the combustion state is not deteriorated. Therefore, it is possible to bring the cooling body sufficiently close to the flame opening without deteriorating the combustion state.
With the radiation cooling function of the cooling body, not only the temperature on the upstream side of the flame but also the temperature on the downstream side can be satisfactorily lowered. Further, since the thin cooling fin is in contact with the upstream side of the flame, the flame temperature will not be lowered more than necessary during weak combustion.

Since a flame rod for detecting the combustion state and a spark rod used for ignition are installed near the flame outlet, interference with these (reduction of flame current during weak combustion or spark on the cooling body during ignition) It is necessary to provide notches or other reliefs in the cooling fins in order to avoid such problems), but since the thickness of the cooling fins is thin, the production of these reliefs is extremely easy.

Further, the cooling body configuration of the present invention is advantageous from the viewpoint of energy saving. For example, in the case of a combustion device that vaporizes liquid fuel with a vaporizer, the cooling fins are located near the heat recovery plate of the vaporizer, and the heat of the heat recovery plate can be partially recovered by radiation. It is possible to shorten the time for energizing the.

Further, since the red-heated cooling body is low in cost and easy to process, it is excellent in reducing NO _x .

(Example) Hereinafter, the Example of this invention is described with reference to drawings.

FIG. 1 shows the structure of the essential parts of an oil fan heater according to an embodiment, and FIG. 2 shows the AA 'cross section. In these figures, 1 is the burner body and 2 is its flame outlet. Three
Is a vaporizer having a vaporization pipe 4 and an electric heater 6 for heating the vaporization pipe 4. That is, when the vaporizing pipe 4 is heated by the electric heater 6, the liquid fuel supplied through the pump passes through the vaporizing pipe 4 and is substantially vaporized, and the nozzle 5
And the surrounding air is drawn into the burner body 1 together with the vaporized fuel. The vaporizer 3 is integrally formed with a heat recovery plate 7 located on the flame port 2 of the burner body 1. The flame port 2 of the burner body 1 is provided with a frame rod 8 for detecting the flame current value and a spark rod 9 for ignition so as to project. Further, a red heat cooling body 11 is provided on the flame port 2. The cooling body 11 has a relatively large width and a cylindrical main body 11 ₁ having a large number of vent holes 12 so that the flame can smoothly flow from upstream to downstream, and a thin cooling formed extending from this to the flame upstream side. and a fin 11 _2. The cooling fins 11 _2, so that can be placed close enough to the cooling body 11 to the flame hole 2 without being obstructed by the flame rod 8 and the spark rod 9, also it does not affect the characteristics of the flame rod 8 and the spark rod 9 Thus, notches 13 and 14 are formed in these portions. The cooling body 11 is attached to the combustion chamber or is attached to the burner body 1 by a support rod or the like.

With such a configuration, the fuel substantially vaporized by the vaporizer 3 is injected from the nozzle 5, and the burner main body 1 together with the surrounding air is injected.
When it enters the flammable range, the spark rod 9
Is ignited by a spark. 10 in the figure is thus flame tip 2
Shows the flame formed above.

Flame 10 formed on the burner, the downstream side with a main body 11 ₁ from the upstream side with cooling fins 11 ₂ red hot cooling body 11, flows through a portion vent hole 12. At this time, the flow of the combustion gas so cooled fins 11 ₂ is thin is smooth unimpeded. Position with a cooling body 11 are flame high temperature portion, in particular the cooling fins 11 temperature _2/5 of a certain upstream is higher combustion reaction is vigorous. Flame rod 8 and the spark rod 9 is adjacent to the flame upstream of the highest temperature region is located to the cooling fins 11 ₂ on the burner, the cooling fins 11 ₂ notches 13 and 14 are provided Therefore, the characteristics are not affected. That is, the spark does not fly from the spark rod to the cooling body 11 at the time of ignition, and the combustion state does not greatly change at the time of weak combustion, so that the flame current value detected by the flame rod 8 does not decrease.

In this way, according to this embodiment, the red heat cooling body is provided at a position close to the burner flame port without adversely affecting the characteristics of the frame rod 8 and the spark rod 9, and the high temperature portion of the flame can be directly cooled by the radiation effect. it can. This makes it possible to effectively reduce the NO _x contained in the exhaust gas. Since the cooling fins 11 ₂ is positioned closer to the heat recovery plate 7 of the vaporizer 3, it is possible to recover some heat from the heat recovery plate 7 by radiation effect. As a result, the power consumption of the electric heater 6 during steady combustion must be reduced, and the heat recovery plate 7 can be downsized, so that the carburetor 3 can be used.
It is possible to shorten the residual heat time until ignition by making the heat capacity of the battery small.

Further, the cooling body structure as described above is easy to process, has a low cost and is excellent in durability, and has an extremely high added value for reducing NO _x .

The present invention is not limited to the above embodiment. For example, the cooling body may have a circular cross section, or may have no ventilation hole if the width is small enough not to deteriorate the combustion state. Further, the cooling body material may be a metal or a ceramic having excellent heat resistance. When the ceramic is used, since there is no spark from the spark rod, the notch provided in the cooling fin can be made small. In other words, the shape of the cooling fins should be appropriate within a range that can keep the NO _x reduction effect, avoid the spark rods and frame rods, and come close enough to the flame port, and that does not impair the characteristics of the spark rods and frame rods. Can be designed.

Further, although the oil fan heater has been described in the embodiment, basically, the present invention can be applied to any combustor that does not select fuel and is provided with a flame rod or a spark rod on the burner flame port. .

[Advantages of the Invention] As described above, according to the present invention, the flame temperature can be reduced by the radiative cooling effect without lowering the flame current value during weak combustion, poor ignition, etc. It is possible to obtain a combustion device capable of effectively reducing the NO _x of the.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of essential parts of an oil fan heater according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA '. 1 ... Burner body, 2 ... Flame mouth, 3 ... Vaporizer, 4 ... Vaporization pipe, 5 ... Nozzle, 6 ... Electric heater, 7 ... Heat recovery plate, 8 ...
Frame rod, 9 ... Spark rod, 10 ... Flame, 11 ...
Cooling body, 11 ₁ ... Cooling body, 11 ₂ ... Cooling fins, 13, 14 ...
Notch.

Claims (1)

[Claims] 1. A flame rod for detecting a combustion state is provided on a burner flame port, and a cooler is provided in a flame formed on the flame burner, which cools the flame by being red-heated by the flame and radiating the flame. In the combustion device, the cooling body includes a cooling body main body arranged on the downstream side of the flame, and a cooling fin formed to be thinner than the cooling body main body and extending from the cooling body main body toward the flame mouth side. Combustion device characterized by being composed of.