JPS6354966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiant burner that centrally heats a predetermined location.

Conventionally, in order to intensively heat a part of the object to be heated, a cup-type radiant burner as shown in Fig. 1,
A porous burner as shown in FIG. 2 is used.

By the way, in a cup-type radiant burner, the cup surface temperature is limited to 1400°C at most, so there is a limit to the amount of solid radiation. Furthermore, since the radiation angle α° of the heat radiation from the red-hot cup surface is large, there is little directivity and the heat flux distribution is gentle. In addition, in porous burners, including those with through holes, the heat radiation is limited to the vicinity of the surface of the porous solid, so there is no directivity, and it is not possible to centrally heat local areas as efficiently as with cup-type radiant burners. It had the following drawback.

The present invention was made as a result of various studies in order to eliminate the drawbacks of the conventional radiant burner, and it prevents overheating of the burner tile, gives directionality to the radiant heat,
The object of the present invention is to provide a radiant burner that centrally heats a local part of a heated body at high temperatures.

Next, the present invention will be explained with reference to drawings which are embodiments.

FIG. 3 is a longitudinal cross-sectional view of the radiant burner A according to the present invention, where 1 is a burner block, 2 is a fuel supply pipe having a fuel injection nozzle 3 at its tip, and 4 is a fuel supply pipe 3.
5 is a diffusion mixing tile; 6 is a preliminary combustion chamber formed in front of the diffusion mixing tile 5; A heat exchanger body 7 made of a heat-resistant material such as zirconia, alumina, graphite, etc. is provided, and has a large number of substantially straight through holes 8. 9 is an ignition hole which is an ignition means.

In the radiant burner A having the above configuration, when fuel is supplied from the fuel supply pipe 2 and combustion air is supplied as a straight flow from the combustion air supply port 4, and combustion is performed by igniting from the ignition hole 9, the fuel and air are After being mixed gently, a part of the combustibles completes the reaction in the pre-combustion chamber 6, and the remaining high-temperature gas containing unburnt materials flows into the small holes 8 of the heat exchanger 7, where a combustion reaction takes place. is completed, the combustion gas is ejected from the small hole 8 toward the object to be heated, and heats the object to be heated.

Incidentally, while the heat exchanger 7 is heated by combustion in the pre-combustion chamber 6, the remaining unburned matter completes combustion within the small holes 8, thereby heating the small holes 8.

In this case, the combustion reaction is rapid because the unburnt material comes into contact with the high-temperature solid wall of the small hole 8, which has a large surface area, and as a result, the wall surface of the small hole 8 becomes extremely hot.

Most of the radiant heat from the wall surface of the small hole 8 heated to a high temperature as described above is released from the small hole 8, but the temperature distribution in this small hole 8 is as shown in FIG. The center point B, where combustion is completed, has a higher temperature than the central point B, and as shown in Figure 5, the radiation angle α from the center (ultra high temperature) point B is equal to the radiation angle α from the outlet side point B'. ′ is smaller than ′.

Therefore, the distribution of ultra-high-temperature solid radiant heat (heat flux) has directionality as shown in Figure 6, and it is possible to intensively and rapidly heat a localized area of the heated object with a large amount of radiant heat. can.

According to experiments, in order to improve the directivity of radiant heat, the small hole 8 is not limited to a circular shape, but it has a shape of about 1 mm to
It is preferable that the ratio of the length l to the equivalent diameter d of the opening is 3 or more, preferably 15 or more, with an opening equivalent to 10-odd mm. However, for a straight heated object, the length is 10
Of course, it is not limited to several mm.

In addition, since combustion is almost completed within the small holes 8, which have a higher temperature and a larger surface area than conventional burners, there is almost no visible flame from the burner outlet even when operating at a low air ratio. Since the ultra-high temperature reaction region is short, the amount of NOx produced is also small.

As is clear from the above explanation, according to the present invention, fuel and air are gently mixed in the burner tile in a straight flow, so the internal temperature of the combustion chamber is 1100~1100~
The temperature is maintained at an appropriate temperature of 1300℃, preventing the burner tile from overheating, and since the combustion of the remaining portion is completed within the small holes of the heat exchanger made of heat-resistant material, the inner walls of the small holes can be heated to ultra-high temperatures. can. Since this ultra-high temperature part is formed in the center of the small hole, the radiation angle to the outside of the burner is smaller than that of conventional burners, and as a result, the heat flux from the small hole wall has directionality. , it is possible to efficiently and rapidly heat a local part of the object to be heated.

Furthermore, since the ultra-high temperature section is a very limited and small portion, the passage time of combustion gas is short, and the generation of NOx is suppressed.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional cup-type radiant burner and a porous burner, and their heat flux distribution diagrams, FIG. 3 is a cross-sectional view of a radiant burner according to the present invention, and FIG. FIG. 5 is a diagram showing the maximum temperature range of the heat exchanger and the radiation angle near the outlet, and FIG. 6 is a heat flux distribution diagram of the burner of the present invention. A... Radiation burner according to the present invention, 2... Fuel supply pipe, 4... Combustion air supply pipe, 6... Preliminary combustion chamber, 7
...Heat exchange body, 8...Small hole.

Claims (1)

[Claims] 1. A fuel supply pipe having a fuel injection nozzle at its tip, a combustion air supply port located outside of this fuel supply pipe that jets air as a straight flow, a diffusion mixing tile, and a combustion air supply port formed at the tip of this diffusion mixing tile. A pre-combustion chamber for stably maintaining combustion, and a large number of approximately linear small through holes with a length-to-diameter ratio of 3 or more, which are located downstream of this pre-combustion chamber and complete the combustion, are arranged approximately parallel to the flame direction. A radiant burner comprising: a heat exchanger made of a heat-resistant material;