JPH0222296B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation enhancer that can improve thermal efficiency when used on the wall of a furnace.It can not only be supplied as a unitized panel, but also can be constructed on-site to construct the furnace wall. It is something that can be used.

Various improvements have been made for the purpose of energy saving in glass melting furnaces, cement firing furnaces, metal heating furnaces such as steel and non-ferrous metals, and other general industrial furnaces.

For example, an existing or new furnace wall is lined with a heat insulating layer made of ceramic fiber. This method has some effect in preventing heat from being transmitted through the furnace wall and escaping to the outside of the furnace, and is useful as an insulated furnace wall, but it does not promote the heating of objects to be heated inside the furnace as a heating furnace. From a point of view, no radiation effect can be expected from the heat insulating layer.

As another example, it is known that a ceramic perforated plate with many irregularities on its surface has the effect of enhancing radiation, and that using such a perforated plate as a furnace lining can help accelerate heating. There is.

Although this method is expected to have the effect of increasing radiation, since the perforated plate is directly lined in front of the furnace wall refractories, there is a large amount of heat loss due to heat conduction through the furnace wall refractories. The reality is that practical use has not progressed because cracks occur in the perforated plate or the refractory, which is thought to be caused by the difference in thermal expansion between the perforated plate and the furnace wall refractory.

In view of these points, the present inventors have conducted various studies, and as a result, have created a radiation enhancement effect in the furnace with a wavelength conversion mechanism by using a perforated plate, and have provided durability to effectively exhibit this effect. At the same time, we succeeded in preventing heat loss due to heat conduction through the furnace walls.
We have previously proposed a construct for this purpose.

That is, such a structure consists of a radiation-enhancing ceramic layer having a large number of holes or grooves on its surface, a variable heat insulating material layer made of heat-resistant fibers, and a heat-resistant solid heat insulating material layer, and each of these layers is further comprised of: The furnace wall is constructed by forming a common hole in a direction perpendicular to the plane of each of these layers, and inserting a substantially T-shaped holder made of ceramic into the common hole.

FIG. 1 shows a typical example, and the structure 1, which is the basis of the present invention, is basically a radiation-enhancing ceramic layer 2 located on the inner surface of the furnace when used or constructed as a furnace lining. It consists of a variable heat insulating material layer 3 made of heat-resistant fibers interposed as an intermediate layer on the back surface thereof, and a solid refractory material layer 4 located further on the back surface thereof.

Although the purpose of radiation enhancement is achieved in this way, one major advantage is that these structures can be supplied as unitary fire-resistant panels.

That is, it can be manufactured in a factory and used as a furnace lining at the site, regardless of whether it is new, existing, or repaired. Of course, the walls (walls, ceiling, etc.) of the furnace having such a structure can also be constructed by on-site construction if necessary.

As described above, these are very useful, but as a result of further various studies, we succeeded in discovering that it is possible to further promote radiation enhancement from the radiation-enhancing ceramic layer while taking advantage of these advantages, and we have published this book. This is proposed as an invention.

That is, the present invention provides a radiation-enhancing ceramic layer having a large number of holes or grooves on the surface, some of which penetrate at least in the thickness direction, to a refractory block through a cushioning material made of heat-resistant fibers. It is a radiation enhancer in which holes or grooves passing through a layer are held in communication with the space on both the front and back sides of the layer, and furthermore, a large number of holes or grooves are formed on the surface, some of which are at least in the thickness direction. A radiation-enhancing ceramic layer having a penetrating structure is attached to a fireproof block through a buffer material made of heat-resistant fibers in a high-temperature gas flow path, so that the through-holes or grooves in the radiation-enhancing ceramic layer are connected to each other on both the front and back surfaces of the layer. A radiation-enhancing heating furnace is provided in which a radiation-enhancing ceramic layer is disposed and held so as to communicate with a flow path and face the upstream side of high-temperature gas.

The present invention will be explained below with reference to the drawings.

The radiation enhancer 10 of the present invention basically consists of a radiation enhancer ceramic layer 11, a buffer material 12 made of heat-resistant fibers, and a refractory block 13, as illustrated in FIGS. 2 and 3. Let me explain first.

The radiation-enhancing ceramic layer 11 has a large number of holes or grooves on its surface (at least the outer surface that is located on the inner surface (high temperature side) when used in a furnace), and at least one of these holes or grooves is The portion is formed to penetrate in a direction perpendicular to the surface of the ceramic layer (thickness direction).

What is shown in FIGS. 2 and 3 is a grid-like thin wall 1
This is a so-called honeycomb-shaped ceramic plate having a large number of through holes 11b divided by 1a, and the one shown in FIG. The one shown in FIG. 1 is a plate-shaped body having grooves 11c formed on one surface in a grid pattern.

In these, since the holes in FIGS. 2 to 4 are through holes, these parts can be used without specially forming the through passages required in the present invention, but as shown in FIG. (or hole) is not penetrated, in addition to these grooves (holes) 11c, a through hole or a through groove for forming a gas flow path, which will be described later, is formed in the thickness direction, although this is not illustrated in FIG. It is necessary to form it.

In this way, since a ceramic layer having a large number of holes or grooves at least on its outer surface is used, when used as a furnace lining, it is possible to improve the emissivity from the wall surface, and the holes formed The number, position, shape, depth, size, etc. of the grooves can be appropriately selected depending on the purpose.

Ceramic materials may be made of ordinary oxides such as zirconia, alumina, mullite, magnesia, cordierite, etc.
It may be made of a non-oxide such as silicon nitride, silicon carbide, or boron carbide.

The cushioning material 12 made of heat-resistant fiber and serving as the intermediate layer is
It maintains heat resistance and flexibility even when used at high temperatures, and is made of a so-called ceramic fiber with a high melting point. Suitable ceramic fibers include alumina silica, alumina, silica, zirconia, titania, silicon carbide, etc. In order to form a layered body, woven fabrics, non-woven fabrics, and cotton-like materials made of these materials may be used. It can be used in any form such as a blanket, sheet, or bundle.

In this way, this buffer material layer 12 acts as an intermediate layer and an effective heat insulating layer at high temperatures for the inner ceramic layer which has been ignited at high temperature and becomes incandescent, and also serves as an effective heat insulating layer for the ceramic layer and the solid refractory block behind it, which will be described later. As a buffer layer between the layers, it is possible to prevent cracks from occurring in these layers and provide a durable structure, and the appropriate thickness for intervening is about 5 to 20 mm.

This cushioning material is provided with a through passage 12a for easy gas flow, which will be described later, similar to the refractory block described next.This through passage 12a is not formed directly in the cushioning material as shown in Fig. It may be formed between the two. By aligning the through holes or grooves of the radiation-enhancing ceramic described above with this through passage 12a, it is possible to form a state in which these holes or grooves communicate with the space.

Next, the fireproof block 13 complements the heat insulation of the high-temperature incandescent ceramic layer as much as possible following the heat insulation provided by the buffer insulation material 12, and
It holds a radiation-enhancing ceramic layer.

The retention of the radiation-enhancing ceramic layer will be described later, but the following materials are suitable as the refractory block.

A preferable refractory block is one that has sufficient strength for the purpose, has as low a thermal conductivity as possible, and can be formed with a sufficient thickness as a refractory material layer.
These do not need to be made of special materials, and may be made of commonly known heat-insulating refractories; for example, they may be precast products made of monolithic refractories (castables), or they may be pressed products. good. As a specific example, a lightweight castable refractory made of aggregates such as porous shamots or alumina hollow particles is suitable.

In addition, depending on the purpose, it is desirable to reduce the thickness of this solid heat insulating material layer, or in cases where this layer particularly requires effective heat insulation at high temperatures, it may be used as an intermediate layer. It is effective to use a fibrous insulation material made of ceramic fibers, such as those used in the Japanese market. It is necessary to block them in advance. This is because if the variable shape is used as it is, it is not only difficult to set it in the furnace, but also the furnace cannot be used stably.

In the present invention, the refractory block 13 is provided with a through passage 13a through which gas can easily flow, as shown in FIG. 2, similar to the buffer material layer described above. As shown in the figure, as in the case of the cushioning material, the material may not be formed on the fireproof blocks themselves, but may be formed between them.

The radiation enhancer of the present invention basically has the following three types.
It consists of a layered structure, and these can be used in a factory-produced panel unit that integrates the three layers in advance and can be applied to the on-site furnace as is, or as a panel unit that is made up of these three layers as the main component. The structure can also be formed in an on-site furnace.

In the former case where it is used as a panel unit and in order to facilitate construction, it is also desirable to bond the boundary surfaces of each of the three layers with a high-temperature adhesive.

Regardless of whether or not this adhesive is used, the radiation enhancer of the present invention can be used as a means of integrating these three layers with a locking member such as a ceramic holder or a holding plate, or in combination with this to fix the holder. It is preferable to use monolithic refractory materials for this purpose, and specific means and preferred examples of how they are used in furnaces will be further explained with reference to FIGS. 6 to 11.

Figure 6 shows a through path 1 through three layers as shown in Figure 3.
Holders (studs) made of ceramic are inserted into common holes 11d, 12d, and 13d, which are formed in advance in common to the ceramic layer 11, the buffer material 12, and the refractory block 13, so that the holes 2a and 13a match.
14 is inserted into the enlarged seat plate 14a of the holder 14.
This is an example in which the ceramic layer is held in the refractory block by holding the ceramic layer down and embedding the leg portion 14b into the hole 13d of the refractory block 13.

FIG. 7 shows an example in which a cushioning material 12 and a refractory block 13 each having through-holes 12a and 13a formed therein as shown in FIG. 2 are laminated, and a ceramic holder 14 is used in the same manner as in FIG. This is an example in which the legs of the ceramic holder 14 are enlarged legs 14b, and this part is filled with a high-strength amorphous refractory material 15 and embedded in the refractory block 13.

8 and 9 show that the ceramic layer 11 can be connected to the fireproof block 13 without necessarily using a locking member.
The figure shows an example in which a holding plate 16 made of ceramic is used as the locking member.

In FIG. 8, a radiation-enhancing ceramic layer is fitted into a through passage 13a of a refractory block 13 so as to be held via a cushioning material 12 by a flange portion 13b formed inside the refractory block. This is an example in which a presser plate 16 made of ceramic is further fitted and fixed. Here, the buffer material 12 may be interposed between the outer surface of the ceramic layer 11 and the inner surface of the refractory block 13. Also, as shown,
Another cushioning material 17 may be interposed between the holding plate 16 and the ceramic layer 11, or the holding plate may be bonded to the fireproof block with an adhesive.

In FIG. 9, the through passage 13a of the refractory block 13 has a pyramidal cross section, making it easier to hold the radiation-enhancing ceramic layer 11. In this case, there is almost no need to use the holding plate 16. Particularly when such a radiation enhancer is used in a ceiling, it is completely unnecessary.

In the examples shown in FIGS. 8 and 9, when the refractory block 13 is used, a part of it is located on the side of the object to be heated, that is, on the high-temperature side of the inner surface of the furnace, similar to the radiation-enhancing ceramic layer. Therefore, more fire-resistant materials are used.

10 and 11 show embodiments of a heating furnace using the radiation enhancer according to the present invention.
The figure shows the walls used as partition walls for heat insulation between high-temperature and low-temperature regions. (In these drawings, the means for attaching the radiation enhancer to the inside of the furnace is omitted.) In FIG. It's the ceiling. A rail 23 is laid at the bottom of the furnace, and a cart 24 carrying a heated object 25 moves on the rail 23, and high-temperature gas, which is hot air, is introduced from the left side of the drawing.

In such a heating furnace, there is the above-mentioned inner ceiling above the area through which the heated object passes, keeping an appropriate distance from the heated object and the ceiling wall, and the heat absorbed from the high-temperature gas is converted into radiant heat to the heated object. It is possible to give. In order to efficiently heat the object to be heated, it is best to increase the convective heat transfer from the high temperature gas to the radiation enhancer, and for this purpose it is necessary to promote gas flow through the radiator. According to the invention, this is possible because the through holes (or grooves) in the radiation-enhancing ceramic layer are adapted to communicate with the hot gas flow passages.

For example, although not shown, by providing a high-temperature gas outlet toward the object to be heated on the lower side wall of the intermediate ceiling, providing an outlet on the upper side wall of the intermediate ceiling, and providing a flue 27 in the ceiling. , the hot gas can be made to flow in the direction shown by the arrow.

That is, by doing this, the heating of the radiation enhancer, which is the inner ceiling, is promoted, and the object to be heated can be efficiently heated by the radiant heat from this body.

In FIG. 11, the radiation enhancer 10 is arranged so that the radiation enhancer ceramic layer 11 faces the high temperature side of the high-temperature gas flow path, without impairing the gas flow shown by the arrow in the gas flow path. High temperature range 20
The effect of the present invention can be sufficiently imparted to the object to be heated 25 by being isolated from the low-temperature region 20b and the low-temperature region 20b.

As described above, the present invention can further promote the heating effect due to radiation enhancement, and has great industrial value.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view for explaining a conventional radiation enhancer, FIGS. 2 and 3 are exploded perspective views for explaining the radiation enhancer of the present invention, and FIGS. 4 and 5 are exploded perspective views for explaining the radiation enhancer of the present invention. FIG. 6 and FIG. 7 are cross-sectional views showing embodiments of the radiator of the present invention; FIGS. 8 and 9 are diagrams showing other application examples of the present invention. 10 is a sectional view, b is a plan view, and FIGS. 10 and 11 are sectional views showing the structure of a heating furnace as another embodiment of the present invention. In the drawings, 10 is a radiation enhancer of the present invention, 11 is a radiation enhancing ceramic layer, 12 is a buffer material, 13 is a refractory block, and 12a and 13a are through passages.

Claims (1)

[Scope of Claims] 1. A radiation-enhancing ceramic layer having a large number of holes or grooves on its surface, some of which penetrate at least in the thickness direction, is attached to a fireproof block through a cushioning material made of heat-resistant fibers. A unitized radiation enhancer for a furnace wall, in which holes or grooves through an enhancing ceramic layer are maintained in communication with the space on both the front and back sides of the layer. 2. A radiation enhancer for a unitized furnace wall according to claim 1, wherein the radiation enhancer ceramic layer is held on the refractory block via a buffer material using a locking member.