JP2538744B2 - Fire resistant shelf - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shelf plate which can be preferably used for firing ceramics, tiles, electronic parts and the like. More specifically, it has excellent spalling resistance and prevents so-called battering phenomenon. About the shelf to get.

[0002]

2. Description of the Related Art Conventionally, as shelf boards used for firing ceramics such as insulators, sanitary ware, tableware, picture frames and ceramic tubes, tiles, etc. A shelf board with improved poling property is known (Japanese Utility Model Publication No. 50-35094). For such refractory shelves, the rate of temperature rise per hour is 400 ° C.
It has been recognized that even under harsh use conditions such as above, the slit relieves stress, and thermal spalling and mechanical spalling are less likely to occur on the shelf.

However, in such a shelf board, there is a problem that foreign particles such as grain sand and coating material scattered on the surface of the shelf board fall from the gap of the slit (so-called battering phenomenon), and in order to prevent this. In addition, a shelf plate has been developed in which mullite, alumina, or the like is embedded in the slit, and good spalling resistance can be maintained and the battering phenomenon can be prevented (Japanese Utility Model Publication No. 54-33974).

[0004]

However, in the conventional shelf board in which mullite, alumina, etc. are buried, the filling material such as mullite, alumina, etc. is at least solidified at the use temperature (baking temperature of the object to be fired). Therefore, these filling materials have relatively high strength. Therefore, under severe conditions of use, since the embedding material has high strength, the slit effect, that is, the effect of dispersing the internal stress cannot be sufficiently exerted, and there is a problem that cracks may occur. .

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to be stable against stress caused by thermal history of temperature rise and cooling and to be resistant to stress. It is an object of the present invention to provide a fire-resistant shelf board that has excellent poling properties and can prevent the battering phenomenon.

[0006]

As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by imparting a predetermined cushioning property to the embedding material, and completed the present invention. Came to do. Therefore, the refractory shelf of the present invention is a refractory shelf provided with a slit portion, wherein the slit portion is embedded with a filler having a press-fitting force of 5000 gf / 1 mmφ or less. .

[0007]

In the refractory shelf of the present invention, the ceramic fiber itself constitutes the filler, or the mortar is mixed with the ceramic fiber, the alumina hollow body and the flour to prepare the filler having a predetermined buffering property. It was decided to embed this filling material in the slit provided on the shelf. Therefore, in the shelf board of the present invention, the stress caused by the temperature rise and cooling is relaxed, and the spalling resistance is improved. Further, the shelf board of the present invention may be one in which a filling material having a predetermined cushioning property is embedded in the slit portion, and it does not matter before or after heating / baking. That is, the slit portion may be filled with a filler such as ceramic fiber and dried, or the shelf plate may be heated and fired. It is considered that flammable substances such as wheat flour, rice flour, and polyethylene powder disappear when the shelf board is used to give porosity to the slit embedding portion, thereby giving a buffer property.

The shelf board of the present invention will be described in detail below. The filler according to the present invention needs to have a predetermined cushioning property as described above. This buffering property is obtained by burying the filler in the slits provided on the shelf and drying at room temperature, and then loading the columnar pin (made of SUS304) of 1 mmφ into the portion where the filler is embedded by 1 mm or more ( Hereinafter, it can be determined by "pressure input". The filler according to the present invention is 5
000 gf / 1 mmφ or less, preferably 1000 gf /
It has a cushioning property represented by a pressure input of 1 mmφ. 50
If it exceeds 00 gf / 1 mmφ, a sufficient slit effect cannot be obtained under severe usage conditions, which is not preferable.

Various methods are conceivable for imparting the above-mentioned cushioning property to the filler according to the present invention, but a method of using the ceramic fiber itself as the filler, a ceramic fiber, a ceramic hollow body, and a combustible substance are mixed in the mortar. And a method of using a low-strength mortar having a reduced amount of clay as a filler. The term "mortar" as used herein means a material having sufficient properties such as plasticity and adhesion by adding clay and a binder to a fine grain raw material of alumina or mullite.

As the above-mentioned ceramic fiber, a fiber capable of imparting a predetermined cushioning property is sufficient, and it is not particularly limited, but mullite fiber, alumina fiber and the like can be mentioned. Also,
It is sufficient for the ceramic hollow body to be able to impart a buffering property, and examples thereof include an alumina hollow body, a mullite hollow body, a silica hollow body, and an arbitrary mixture thereof. Furthermore, examples of the flammable substance include wheat flour, rice flour, carbon powder, walnut flour, polyethylene powder, polystyrene powder, and any mixture thereof.

The shelf board of the present invention can be obtained by forming a slit in the shelf board base material and burying the above-mentioned filling material in the slit. Examples of this shelf board base material include SiC, mullite, cordierite and the like. The filling material can be embedded either before or after the baking of the shelf base material. Further, after the filler is embedded in the shelf board of the present invention, it is desirable to coat the surface thereof with alumina, mullite or the like in order to prevent reaction, sticking, etc. with the product to be fired. Further, the slit portion can be formed by making a cut from the edge of the rectangular shelf plate in the direction of the opposite edge. The number of slits is not limited to two, but may be four or six depending on the size of the shelf and the use conditions. It is desirable that each slit portion is arranged at a position symmetrical with respect to the center of gravity of the shelf board, and the cross-sectional shape thereof is V-shaped or T-shaped as described in Japanese Utility Model Publication No. 54-33974. It may be in the shape of a letter.

[0012]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. (Examples 1 to 17 and Comparative Examples 1 to 4) As SiC aggregate particles, 95% by weight of particles having a particle diameter of 3 mm or less, 2% by weight of bentonite, methylcellulose and water were mixed to obtain a forming raw material. This molding raw material is introduced into a mold and molded using a vibration press, 400 mm × 350 mm × 10 mm
A (thickness) molded body was obtained. At this time, slits 10, 11, 12 and 13 were provided as shown in FIG.

The obtained molded body was subjected to 140 ° C. in an oxidizing atmosphere.
The shelf base material was obtained by firing at 0 ° C. for 3 hours. At this time,
The rate of temperature increase and decrease was 100 ° C./hr. The slits of the obtained shelf board base material were filled with the fillers shown in Tables 1 and 2 and then subjected to mullite coating to obtain a fire resistant shelf board. About this shelf board, which is the operating temperature range 1200-
Heat treatment was performed at a temperature of 1400 ° C., and the obtained shelf boards were subjected to the following performance evaluations, and the results are shown in Tables 1 and 2.

(Performance evaluation) (Cushioning property) In the filler portion embedded in the slit of each shelf,
The load (pressing force) necessary to press-fit a 1 mmφ cylindrical pin (made of SUS304) for 1 mm or more was measured. This measurement was performed with an autograph equipped with a load cell (manufactured by Shimadzu Corporation). (Spalling resistance) The length of cracks generated when the shelf plate was heated to 1400 ° C. at a temperature rising rate of 300 ° C./hr and held at this temperature for 30 minutes, then taken out from the furnace and rapidly cooled to room temperature. Was measured.

(Prevention of Tattering) In the above-mentioned spalling resistance test, a container was placed below the slit, and it was determined whether or not foreign matter had fallen into this container. (Normal temperature bending strength) A three-point bending strength test was performed at room temperature according to JIS R1601.

[0016]

[Table 1]

[0017]

[Table 2]

(Examples 18 to 20) Shelf plate base materials were prepared under the same raw materials and the same conditions as in Examples 1, 5, and 7, and the same fillers were embedded therein. Then, after drying at room temperature for 12 hours, the surface was directly subjected to mullite coating without being heated and fired to obtain fire-resistant shelf boards of Examples 18 to 20. The performance of each of the obtained shelves was evaluated in the same manner as in the above example, and the results are shown in Table 3.

[0019]

[Table 3]

As is clear from Tables 1 to 3, it can be seen that the refractory shelf according to the present invention has excellent spalling resistance and can prevent the battering phenomenon.

[0021]

As described above, according to the present invention,
Since it was decided to give the embedded material a certain cushioning property,
It is possible to provide a refractory shelf that is stable against stress generated by the heat history of temperature rise and cooling, has excellent spalling resistance, and can prevent the battering phenomenon. Therefore,
The fire-resistant shelf of the present invention is preferably used for a rapid baking furnace shelf that emphasizes spalling resistance and the like, a pot, a kiln tool such as a pod, and particularly a tile baking shelf using a roller hearth kiln. it can.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a shelf base material with slits according to the present invention.

[Explanation of symbols]

 10, 11, 12, 13 slits

Claims (6)

(57) [Claims] 1. A refractory shelf having a slit portion, wherein the slit portion is filled with a filler having a pressure input of 5000 gf / 1 mmφ or less. 2. The refractory shelf according to claim 1, wherein the filler contains a ceramic fiber. 3. The refractory shelf board according to claim 1, wherein the filler contains one or more kinds of hollow bodies selected from the group consisting of alumina, mullite and silica hollow bodies. 4. The refractory shelf board according to claim 1, wherein a material containing a flammable substance is used as the filler, and the flammable substance is extinguished by heating and firing the filler. . 5. The flammable substance is one or more substances selected from the group consisting of wheat flour, rice flour, carbon powder, walnut flour, polyethylene powder and polystyrene powder. Fire resistant shelf as described. 6. The refractory shelf according to claim 1, wherein the filler is made of low-strength mortar with a reduced clay content.