JPS5993177A - Flame heat barrier - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] FIELD OF THE INVENTION This invention relates to flame thermal barriers.

Flame thermal barriers can be used to control the flame flow in a furnace or
It is used for purposes such as insulation, heat retention, and heat shielding, but it is generally exposed to severe thermal shock due to violent collisions with flames.

For this reason, ordinary bricks or similar materials cannot be used because of thermal cracking. Furthermore, products using ceramic fibers are certainly safe against thermal cracking, but there are cases where the fibers are blown away by flames, or deteriorated to pieces due to repeated rapid heating and cooling. Something is happening.

The present inventor has reviewed the history of such prior art.

We have conducted extensive research to create the ideal flame heat barrier.

A structure has been devised that is extremely superior in terms of thermal efficiency, i'I durability, and economic efficiency.

The gist of the present invention is a flame heat barrier made of a ceramic face piece, in which at least the part of the face piece that comes into contact with the flame is composed of a thin ceramic plate or a ceramic rod-like body divided into thin pieces of 1 that are below a critical value for thermal cracking. It is a flame heat barrier made up of a 9th order, and was made based on completely new findings such as the 9th order.

That is, the ceramic facepiece of the above structure has various functions such as surface thermal shock resistance, thermal shielding property, radiant heat reflection property, and surface flame impingement property in a flame heating furnace.

Furthermore, a function has been created that allows the fang 1 to expand and contract freely in response to the expansion and contraction during heating and cooling of the heating furnace. , radiant heat is reflected by the ceramic face piece,
Since the heat is focused on the object to be heated, the heating temperature characteristics of the object to be heated are significantly improved.

Thirdly, when used in the protection wall of the insulating ceramic fiber surface, it can prevent the escape of the ceramic ribbon rivet due to flame impingement, and create a large temperature drop between the back side of the protection wall, which makes it easier to This was based on the completely new finding that even fibers with low densities can be used and deterioration is reduced. Furthermore, the present invention was made based on another completely new finding, such as the first order.

That is, 5 thin plates made of ordinary practical ceramic materials,
In the case of direct flame heating, as a general characteristic, cracks occur in most cases, although there are differences in degree; however, in the present invention, the occurrence of such cracks is not allowed at all. As a result of extensive research into this problem, the inventor of the present invention found that the generation of chilen when a ceramic thin plate is heated with flame varies relatively depending on the material, shape, heating conditions, etc., but the size factor is the most dominant factor. Moreover, we found that this factor has a critical point.

When the ceramic plate was cut into thin strips and the correlation between IJ and crank was investigated, it was found that if the thickness became thinner than this point, no cracks would occur at all. is. Moreover, in this case, the occurrence of cracks is
It depends on the lJ of the band, but not on its length. In other words, we discovered that it doesn't matter how long the length becomes. The present inventor expressed the value of this critical point in the term "medium critical"9, but the present invention shows that if a thin ri band-shaped ceramic thin plate having a value below this critical value is used in combination, it will be stable against heat exposure. This was made possible by the completely new knowledge that it was possible to make face pieces.

Here, I would like to add a little more information about criticality [1].

This value is a value that relatively changes depending on the ceramic composition, plate thickness, and heating conditions. In the case of normal alumina, with a thickness of 0.5M, when heated with gas in combination with oxygen, approximately 2. s wa +l'' is the critical value.

Next, an embodiment of the structure of the present invention will be described with reference to the drawings.

Figure 9 is an explanatory diagram of the cross-sectional structure when the present invention is applied to the furnace wall of a heating furnace, where (1) is the furnace shell and (2) is the hearth. (3) is a flame barrier (barrier) made of a ceramic facepiece, and this barrier forms the inner wall of the furnace.The barrier is installed on the furnace shell by an appropriate method.In this example, a simple jig (4 ), but this is simply described for the sake of explanation, and in reality, it can be done not directly on the furnace shell, but with some intermediate means installed, or Other measures may also be adopted on a case-by-case basis.

A heat insulating layer (5) is formed in the gap between the barrier and the furnace shell.

The insulation layer is generally formed by filling with ceramic fibers, but also with other insulation materials such as brick.

It can also be used as a supplement. Alternatively, a barrier can be constructed by forming an additional layer of insulation inside the brick wall. In this example, there are no restrictions on the structure itself of the heat insulating layer, and the essential point is that sufficient heat insulation is maintained.

During actual operation, this furnace is exposed to high-temperature flames inside the furnace.

Hot air circulates, but the flame is effectively reflected by the barrier.゛There is still space between the barrier and the insulation layer on the back side.

Since a large temperature difference is created, the temperature change in the heat insulating layer becomes gentle, and since there is no direct contact with the flame, 1. Prevents fiber deterioration and flame dissipation that occurs in normal heating furnaces. be done.

Further, since the radiant heat is reflected toward the inside of the furnace by the barrier, the temperature increase characteristic of the object to be heated (6) is promoted.

2 and 3 are perspective views of another embodiment of the structure of the barrier of the present invention and the ceramic plate constituting the ceramic face piece.

Figure 2 is a perspective view of the barrier when a facepiece is formed by combining ribbon-shaped ceramic thin plates with a thickness of +lJ below the critical value. ) utilizes the rigidity of the lattice, and each leaf is held in a sandwiched structure (=J), so that each leaf can be freely displaced with respect to the lattice and with respect to the other leaves.

Structurally, each leaf is mutually independent and is not affected by other stresses. Furthermore, since the lattice can be made into a discontinuous structure divided into appropriate lengths, the large overall strain is also distributed to each leaf and each lattice. For this reason, a considerable degree of deflection is now allowed on the mask.

During normal actual operation of a heating furnace, the furnace wall expands and contracts during heating and cooling, so the furnace wall must have a certain degree of elasticity.

It has sufficient elasticity and flexibility.

It has the characteristic of being able to deal with this freely without causing undue distortion to others.

In addition, when constructing this barrier, it is possible to construct the barrier by inserting a tome tool into the gap between the ceramic plates. This structure is also superior in that there is no need to drill new holes for installation.

In addition to ceramics, heat-resistant metals can also be used as the material for the grid, but ceramic is the most preferable. It is essential to set the value below the critical value.

Fig. 3 shows a case in which a thin [I] sori-ribbon-shaped ceramic plate is used for the lattice in the case of Fig. 2, and in this case, [1] of the ribbon-shaped lattice naturally has a value less than the above critical f1a. It is necessary to set it to .

Fig. 4, wide 1)] is made by making slits in the ceramic plate and dividing it into narrow [1] bands below the critical value. The evaluation can be made in the same way as in the case of . Compared to the cases shown in Figures 2 and 3, construction is easier because a wide rl JO board can be used.

Several embodiments of the present invention have been described above with reference to FIGS. 1 to 4.
The present invention is not limited to this, but can also be installed in the furnace, for example literally as a barrier to change the direction of the flame, and instead of the ceramic plate shown in FIGS. It is also possible to use a rod-like material whose value -11 is less than the critical value.

There are the following methods for assembling the barrier of the present invention.

(1) A method of forming and firing ceramic grids and plates in advance, and then assembling them into the structure shown in Figure 9.

(2) Method of assembling and firing before firing.

These selections should be used appropriately depending on the purpose, application, and situation.

Identification of ceramic materials used in the present invention 1. temperature, atmosphere,
The material should be selected in consideration of heating conditions, required strength, etc., and there are no restrictions on the material itself. The shape of the lattice can be appropriately selected depending on the intended use, such as a line, a single bar, or a band.

As detailed above in the present invention, thermal efficiency, IiI durability.

It is a flame heat barrier with outstanding economic efficiency, and can be used in metal and ceramic firing furnaces, heat treatment furnaces, etc.

It can also be widely applied to melting furnaces, etc.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a cross-sectional structure when the present invention is applied to a furnace wall of a heating furnace. 2 and 3 are perspective views of the structure of the ceramic face piece and another embodiment of the ceramic plate of the present invention. FIG. 4 is a perspective view of a wide ceramic plate made by making slits to divide it into narrow pieces.

Claims (1)

[Claims] A flame heat barrier consisting of a ceramic facepiece, in which at least the part of the facepiece that comes into contact with the flame is composed of a ceramic thin plate or a ceramic rod-shaped body divided into thin pieces with a thickness below a critical value for thermal cracking.