JPH08210610A - Solid radiant burner - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure the seal of the flashback prevention layer in a solid radiant burner and to ensure safe operation with sufficient mechanical strength. [Composition] A burner for surface combustion in which a solid radiation layer for rectification, a flashback prevention layer, and a solid radiation layer for heat dissipation are arranged in the order of mixed gas flow inside a burner casing,
The flashback prevention layer includes a refractory layer placed on a back plate joined to the inner wall of the burner casing by welding all around, and a solid for radiating the mixed gas through the back plate and the refractory layer. A plurality of flow passage holes that flow down to the radiation layer side. The flow path hole may be a nozzle that is integrally joined to the back plate and penetrates the refractory layer, and the refractory layer may be formed by a ceramic fiber castable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid radiant burner of the type in which radiant heating is performed by radiating heat from a solid radiant layer, and more particularly to improvement of a seal structure for a flashback prevention layer.

[0002]

2. Description of the Related Art A solid-state radiant burner is, for example, the actual open sho 63.
As described in Japanese Patent No. 5230, a solid radiation layer for rectification is provided in a chamber to which a mixed gas such as fuel and oxygen is supplied, and another solid radiation layer is provided also on a heat radiation surface downstream thereof. The basic structure is to provide a flashback prevention layer in the space formed between the radiation layers. And
The supplied mixed gas burns in the space between the flashback prevention layer and the solid radiation layer on the heat radiation surface side, and the solid radiation layer can be red-heated by the heat of combustion to obtain solid radiation heat.

The flashback prevention layer exposed to the combustion surface is formed of a material having a low thermal conductivity and has a large number of small holes for feeding the mixed gas into the combustion portion at high speed. Here, the passage speed of the mixed gas through the small holes needs to be higher than the combustion speed. And 1 by combustion of mixed gas
In order to be able to cope with a temperature atmosphere of about 000 ° C., it is considered effective to configure the flashback prevention layer with a refractory material.

[0004]

However, when a flashback prevention layer is formed of a refractory and incorporated into a burner casing, a special structure is adopted for the seal between the periphery of the flashback prevention layer and the inner wall of the burner casing. Unless otherwise, the mixed gas leaks from the seal portion to the combustion side, and the passage speed becomes lower than the combustion speed. This is because even if the peripheral surface of the refractory material is covered with a metal member, it is inevitable that a minute gap is generated due to a difference in thermal expansion due to a difference in material.

If there is such a seal failure, and if the pressure on the upstream side of the flashback prevention layer drops during combustion, the flame will flow upstream from the seal between the flashback prevention layer and the burner casing. A flashback phenomenon occurs toward the. For this reason, stable combustion of the burner is impaired, and it is necessary to interrupt the combustion in some cases.

When a flashback occurs, a considerable impact is applied to the flashback prevention layer itself. For this reason, when the flashback prevention layer is formed of a refractory, the flashback prevention layer may be destroyed because the strength against an impact load is small.

Thus, in the conventional solid-state radiant burner,
There are still problems with the flashback layer seal and its strength.

The problem to be solved in the present invention is to ensure the sealing of the flashback prevention layer in a solid radiant burner and to allow safe operation with sufficient mechanical strength.

[0009]

According to the present invention, a supply passage for a mixed gas is connected to a burner casing, and a solid-state radiation layer for rectification, a flashback prevention layer, and A burner for surface combustion in which solid radiation layers for heat dissipation are arranged with spaces, respectively, the flashback prevention layer, a back plate in which the entire circumference is welded to the inner wall of the burner casing, and the back plate. A refractory layer disposed on the plate, and a plurality of flow passage holes that penetrate the back plate and the refractory layer to allow the mixed gas to flow down to the solid radiation layer side for heat dissipation. And

In such a structure, the flow passage hole can be a nozzle that is integrally joined to the back plate and penetrates the refractory layer.

Further, the refractory layer may be formed by a ceramic fiber castable.

[0012]

Since the back plate of the flashback prevention layer is joined to the inner wall of the burner casing by welding, leakage of combustion gas from the solid radiation layer side for heat radiation toward the upstream side is eliminated, and flashback is prevented. In addition, stable combustion enables heating.

When the nozzle is integrally provided on the back plate and the nozzle is arranged to penetrate the refractory layer, the mechanical strength of the refractory layer is compensated not only by the back plate but also by the nozzle, which causes cracks. Flashback is also prevented.

Further, since the strength of the refractory layer itself is small due to the strength compensation by the back plate, the ceramic fiber castable having good spalling resistance can be used as the material of the refractory layer, and the life of the refractory layer can be improved. Also improves.

[0015]

FIG. 1 is a longitudinal sectional view of a main part showing an embodiment of a solid radiant burner according to the present invention.

In the figure, for example, a burner casing 2 is incorporated in a furnace body 1 of a heat insulation furnace. The burner casing 2 is formed in a rectangular frame shape as shown in FIG. 2, and a mixed gas supply pipe 3 is connected to the bottom plate 2a at the lower end.

A space as a mixed gas supply chamber 2b is formed on the bottom side of the burner casing 2, and a rectifying solid radiation layer 4 is provided on the space. The solid radiation layer 4 uses a metal net, and the periphery thereof is a frame-shaped support 4 a which is fixed to the inner wall of the burner casing 2.

A solid radiation layer 5 for heat radiation is provided on the upper end of the burner casing 2. The solid radiation layer 5 is integrally connected to the burner casing 2.

A flashback prevention layer 6 for preventing flashback is provided between the solid radiation layers 4 and 5 for rectification and heat dissipation. The flashback prevention layer 6 is a back plate 6a having a planar shape that matches the inner wall of the burner casing 2, and the back plate 6a.
A plurality of nozzles 6b in which the axes are arranged in a vertical posture and a refractory layer 6c filling the entire upper surface of the back plate 6a.
It is composed by.

The back plate 6a is made of an iron plate having an appropriate thickness, and its peripheral wall is abutted against the inner wall of the burner casing 2 and is integrated with the burner casing 2 by welding W. By such welding W, the upper and lower sides of the flashback prevention layer 6 are completely cut off from each other, and the gas passage is limited to the opening portion of the nozzle 6b.

The nozzles 6b are made of metal pipes, and are arranged in a large number in a fixed pitch arrangement as shown in FIG. Then, as shown in the enlarged cross-sectional view of FIG. 3, the nozzle 6b has a male screw 6b-1 provided on the outer periphery of the lower end thereof.
Is screwed into the female screw hole 6a-1 formed in the back plate 6a or is fixed by welding.

The refractory layer 6c is formed by filling castable refractory material and molding it into the shape shown in FIG. 1, and is joined to the upper surface of the back plate 6a. The nozzle 6b serves as the refractory layer. It is filled so as to be submerged in 6c. As the material for the refractory layer 6c, various castable refractory materials can be used, but it is preferable to use ceramic fiber castables which are less likely to cause cracks due to long-term use.

In the above structure, the mixed gas sent from the supply pipe 3 to the supply chamber 2b of the burner casing 2 is rectified by the mesh of the solid radiating layer 4 for rectification, and is mixed with the flashback prevention layer 6. It is introduced evenly in the space between. Then, due to the flow of the mixed gas, the mixed gas flows upward from the nozzle 6b, and is ignited by the igniter (not shown) in the solid radiation layer 5 for heat dissipation and burned.
Due to the combustion heat of this combustion, the solid radiant layer 5 is red-heated and the sensible heat of the combustion gas is converted into solid radiant energy,
This heats the inside of the furnace body 1.

On the other hand, the space between the flashback prevention layer 6 and the rectifying solid radiation layer 4 is heated by the heat conduction of the flashback prevention layer 6 itself. At this time, the flashback prevention layer 6 is the refractory layer 6
Since the thermal conductivity is small due to the inclusion of c, the flashback prevention layer 6
The heat transfer to the lower side of the can be mitigated, and flashback is prevented.

Since the backfire prevention layer 6 joins the back plate 6a made of an iron plate to the inner wall of the burner casing 2 by welding W, it is provided between the peripheral surface of the refractory layer 6c and the inner wall of the burner casing 2. Even if there is a gap, leakage of combustion gas to the rectifying solid radiation layer 4 side is prevented. Therefore, the occurrence of flashback is effectively suppressed, and the occurrence of cracks in the refractory layer 6c due to impact is prevented.

Further, even if a flashback occurs, the refractory layer 6c is lined by the back plate 6a, so that the mechanical strength against impact or the like becomes high. For this reason,
In addition to being able to prevent damage to the flashback prevention layer 6 as a whole, the refractory layer 6c itself does not require strength, so even a ceramic fiber castable having good spalling resistance can be used without any trouble. Therefore, by using this ceramic fiber castable as a material, it is possible to reduce the occurrence of cracks in the refractory layer 6c due to long-term use, and it is also possible to suppress the occurrence of flashback due to these cracks.

Further, since not only the back plate 6a but also the nozzle 6b using a metal pipe is embedded in the refractory layer 6c, it is possible to obtain the strength compensation of the refractory layer 6c by these nozzles 6b. it can.

[0028]

According to the present invention, even when the flashback prevention layer is provided with the refractory layer, the backplate can completely prevent the leak of the mixed gas with the burner casing, so that the flashback is prevented. The occurrence of damage and damage due to impact are prevented.

Further, since the back plate compensates the mechanical strength of the refractory layer, even if a backfire occurs, the degree of damage can be reduced, and the refractory layer itself does not require strength, so A ceramic fiber castable having a good poling property can be used, and a refractory layer in which cracks are suppressed can be provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a main part of a solid-state radiant burner of the present invention.

FIG. 2 is a plan view showing a solid radiation layer for heat radiation removed from FIG.

FIG. 3 is an enlarged vertical sectional view showing a main part of a flashback prevention layer.

[Explanation of symbols]

 1 Furnace Body 2 Burner Casing 2b Supply Chamber 3 Supply Pipe 4 Solid Radiation Layer (For Rectification) 5 Solid Radiation Layer (For Heat Dissipation) 6 Flashback Prevention Layer 6a Back Plate 6b Nozzle 6c Refractory Layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masataka Hase 2-6-3 Otemachi, Chiyoda-ku, Tokyo Within Nippon Steel Corporation (72) Masakazu Taguchi 2--6, Otemachi, Chiyoda-ku, Tokyo No. 3 In Nippon Steel Co., Ltd. (72) Inventor Sanji Asano 2-6-3 Otemachi, Chiyoda-ku, Tokyo Inside No. 3 Nippon Steel Co., Ltd. (72) Inventor Osamu Saki Tobata, Kitakyushu, Fukuoka 59 Nittetsu Plant Design Co., Ltd., Nakahara No. 46 (72) Inventor Eiichi Hamamori 1-9-10 Sanno, Yawatahigashi-ku, Kitakyushu City Kuchiki Industry Co., Ltd.

Claims (3)

[Claims] 1. A burner casing is connected to a mixed gas supply passage, and a rectifying solid radiation layer, a flashback prevention layer, and a heat radiating solid radiation layer are provided inside the burner casing in the order of the flow of the mixed gas. A burner for surface combustion arranged with a space, wherein the flashback prevention layer has a back plate joined to the inner wall of the burner casing by welding all around, and a refractory material arranged on the back plate. A solid radiant burner composed of a layer and a plurality of flow passage holes that penetrate the back plate and the refractory layer to allow the mixed gas to flow down toward the solid radiant layer for heat dissipation. 2. The solid radiant burner according to claim 1, wherein the flow path hole is a nozzle that is integrally joined to the back plate and penetrates the refractory layer. 3. The solid radiant burner according to claim 1, wherein the refractory layer is a ceramic fiber castable.