JP4777688B2 - Ceramic kiln, firing method and auxiliary fuel for ceramic industry - Google Patents

Description

  The present invention relates to a ceramic kiln that is heated at a high temperature for firing an unfired fired product formed of a plastic material such as clay, and a firing method using the same, and more particularly, a hollow-type coating on a ceramic surface. The present invention relates to a kiln for a ceramic industry and a firing method capable of firing ceramics excellent in texture.

Conventionally, pottery has been fired in a single-chamber hole kiln using the slope of a mountain or a climbing kiln divided into a plurality of high and low rooms. In both cases, the fuel used was soot. Such conventional kilns can be used to burn pottery with a unique coating on the surface, so-called ash fog or fire color, and are therefore often used in the field of production of highly interesting pottery. I came. In particular, the climbing kiln, which is said to have been transmitted from a Chinese pot in the Middle Ages, can fire pottery with a unique taste.

  However, a kiln using firewood as a fuel has a low calorific value due to the fire of firewood, so it takes a long time to fire the pottery. Moreover, the procurement of firewood as fuel is becoming difficult from the viewpoint of protecting forest resources. Therefore, the hole kiln and the climbing kiln that consume a large amount of firewood tend to gradually reduce the number of firings. In addition, in order to construct a hole kiln or climbing kiln, it is necessary to be an inclined land or to create a large place that satisfies such conditions. At the same time, hole kilns and climbing kilns are not feasible in the neighborhood of the house because black smoke is emitted during firing.

  Therefore, at present, burner-type kilns using kerosene, heavy oil, or gas are mainly used. However, the kiln using an oil burner or gas burner does not contain any material that forms a ceramic film on the fuel itself, so only a pottery in a “baked” state can be obtained. It is not possible to bake ceramics with a coating.

Therefore, for example, as described in Japanese Patent Application Laid-Open No. 10-212153, a kiln using a petroleum burner or a gas burner is used in combination with a firewood to fire a ceramic having a unique coating that is fired in a firewood kiln. Attempts have been made.
However, although the burning time can be shortened by using an oil burner or a gas burner, the problem of the wood kiln as described above remains because the firewood is used. Moreover, the combined use of soot fuel with oil burners or gas burners having different calorific values makes it particularly difficult to manage soot fuel combustion, which makes it difficult to fire pottery as expected.
JP-A-10-212153 JP 2003-238231 A

   In view of the problems in the firing technique of the fired product in such a conventional ceramic kiln, the present invention provides a fired product having a unique enamel-like film that is very easy and fired in a wood kiln in a short time. It aims at providing the kiln for ceramics which can be baked, and the baking method using the same.

   In the present invention, as a result of various studies in order to achieve the above object, it has been noted that it is extremely effective to use it as an auxiliary fuel in which coffee bean shells and ash are mixed. It was also noted that it was effective not to burn the auxiliary fuel in a bowl but to put it near the flame of the burner burning at high temperature in the kiln.

The present invention made based on such attention is characterized by the use of auxiliary fuel obtained by mixing coffee bean shells and ash. And the flame introduction port 3 which introduces a flame into the inside of the kiln 1 surrounded by the refractory, the chimney 4 which discharges exhaust gas from the kiln 1, and the fired product 9 which is provided inside the kiln 1 and is heated by the flame And a firing place 8 to be placed, and an opening (6) into which auxiliary fuel mixed with coffee bean shells and ash is introduced on the outer wall of the kiln (1). Such a charging port 6 uses a kiln for ceramics which can be opened and closed by a lid 7 made of a refractory.

  Furthermore, the firing method of the fired product according to the present invention using such a ceramic kiln is the temperature at which the fired product is fired in the interior of the kiln 1 by blowing the flame of the burner 2 from the flame inlet 3 into the interior of the kiln 1. The fired product 9 is fired while the auxiliary fuel mixed with the coffee bean shell and the ash is charged into the kiln 1 from the charging port 6 while being heated to the inside.

    According to the results actually conducted by the present inventors, in the ceramic kiln and the firing method using the same, an enameled (glassy) film is formed on the surface of the fired product, which makes the fired product unique. You can bring out the texture of the surface. This enamel-like film is almost the same as the surface state of the baked goods baked in a hole kiln or climbing kiln using soot fuel, and it obtains a texture equivalent to the baked goods called ash fog or fire color as an industry term I can do it. In addition, by changing the blending ratio of the coffee bean husk and the ash, there is an advantage that a hollow texture film having a different texture can be formed.

  Furthermore, since the firing is performed by a burner using oil or gas as a main raw material, the firing temperature is extremely easy to control and the firing time is short. In addition, the auxiliary fuel is not burned in the form of a soot, but is introduced near the flame of the burner, so there is little generation of burning debris. Since the charge can be finely adjusted, it is very easy to control the formation of the enamel coating on the surface of the fired product. Furthermore, since it can be applied to a very small ceramic kiln as compared to conventional hole kilns and climbing kilns, there is also a small amount of expressive and artistic fired products that are fired using a small ceramic kiln. Any of the mass-produced products fired using a relatively large ceramic kiln can be easily applied.

As described above, in the present invention, the auxiliary fuel mixed with the coffee beans shell and the ash is not burned in the form of a bowl, but is introduced near the flame of the burner burning at a high temperature in the kiln. Thus, a fired product having an enameled enamel coating with a good texture can be fired.
Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  1 and 2 show an embodiment of a ceramic kiln according to the present invention. The kiln 1 is provided with a wall made of refractory material on a floor made of refractory material, and is formed in a dome shape as a whole. A flame introduction port 3 for introducing a flame from the burner 2 to the inside of the kiln 1 is provided at the lower part of the one end. A chimney 4 for exhausting hot air inside the kiln 1 is erected on the upper end of the other end of the kiln 1. As the burner 2, a general burner such as a kerosene, light oil, heavy oil or other oil burner or a gas burner is used, and no soot fuel is used.

On the floor of the kiln 1, a laying plate made of a refractory material such as a brick is installed, and a fired material storage space 8 is formed so as to rise in a stepped bed shape from the flame inlet 3 side toward the chimney 4 side. On top of this, a fired product 9 made of ceramic material such as clay and made unglazed is placed.
A side of the wall of the kiln 1 near the flame inlet 3 is provided with an inlet 6 through which auxiliary fuel mixed with coffee bean shells and ash is introduced. A viewing window 10 for observing the flame inside the kiln 1 and the state of the fired product 9 is provided at the upper part of the wall of the kiln 1. Although the insertion opening 6 and the viewing window 10 are different in size, they are basically the same shape and can be opened and closed by the lid 7. Therefore, the insertion port 6 may be used as a viewing window for observing the inside of the kiln 1, and the viewing window 10 may be used as an insertion port for introducing auxiliary fuel. A thermocouple 12 for measuring the temperature inside the kiln 1 is introduced from an appropriate observation window 10.

  On the side near the chimney 4 at the top of the kiln 1, a dome-shaped room called “abandonment” is provided in a wood kiln. The portion 5 of the throwing away serves not to let the flame escape straight from the chimney 4 to the outside, and once the heat in the kiln 1 is accumulated in the throwing away 5, the temperature and firing atmosphere in the kiln 1 are stabilized. This is a firing chamber that is made in a hole kiln or climbing kiln. However, it is not made in all the anagama and climbing kilns, and even if it is made, the temperature inside the kiln may not be raised to the target temperature of other firing chambers. Sometimes used as an unglazed dish.

  Further, a draft port 11 is provided on the side surface of the chimney 4. The draft port 11 is an opening for creating an oxidizing atmosphere or a reducing atmosphere by changing the amount of air (oxygen) flowing into the kiln. Hot air is generated from the chimney as a naturally exhausting updraft due to the temperature difference between the inside and outside of the furnace, and an oxidizing atmosphere is created by increasing the displacement, and conversely, a reducing atmosphere is created by reducing it. It is used by closing up to a constant temperature of around 970 ° C., but after that, in order to create an atmosphere in the furnace, the opening is appropriately expanded or narrowed with a refractory brick or the like.

  Such a ceramic kiln is placed in the fired product storage place 8 without applying glaze to the fired product 9 that has been unglazed. Thereafter, the burner is lit and the temperature inside the kiln 1 is raised. The temperature is raised to about 900 ° C. to 1000 ° C. over about 6 hours. Thereafter, the inside of the kiln 1 is kept in a reducing atmosphere, and the fired product 9 is fired while maintaining a temperature of about 1250 ° C. for 2 to 3 hours.

  In the normal baking process, the baking ends here, but in that case, it is merely a “baked” state, and no enamel film is formed on the surface of the fired product 9, resulting in a ceramic product with no fun. End up. On the other hand, in the present invention, the lid 7 of the inlet 6 of the kiln 1 is opened as shown in FIG. 3 (a) while maintaining the above-mentioned temperature of 1250 ° C., and the glaze as shown in FIG. 3 (b). The auxiliary fuel containing the above components is continuously fed into the furnace for 3 to 4 hours. The added auxiliary fuel burns while being flown by the flow of the flame as shown by an arrow in FIG. 3B, becomes high temperature, and the ash which is the glaze component of the auxiliary fuel is formed in the fired product 9 in the kiln 1. Adhere to. As a result, the surface of the fired product 9 is vitrified to form a hollow-shaped film, and a fired product called ash fog is completed. Auxiliary fuel should be added to the burner closest to the flame. If the auxiliary fuel is put directly into the fire, there will be a malfunction inside the kiln, so it should be put in the place closest to the flame of the burner.

The surface film of the fired product produced by this firing method has a very natural texture as if it were fired in a kiln using soot fuel. In other words, it is possible to create a unique baked fire that can only be produced in a hole kiln or climbing kiln called fire back and fire table.
The auxiliary fuel to be put into the kiln 1 is a mixture of coffee husk and ash as appropriate. The coffee husk uses the powdery residue after roasting the coffee seeds and extracting the coffee with a ground one. This is disposed of with household waste at home. Moreover, the residue of the coffee husk produced when a beverage maker manufactures a coffee beverage is disposed of as industrial waste. The ash is mainly wood ash, and ash such as pine, cypress, kunugi and oak is used. In addition, some earth and ash may be mixed. These coffee husks and wood ash, which is the raw material of the glaze, are mixed and used as auxiliary fuel.

Since the types of coffee husk and wood ash and the blending ratio thereof affect the texture of the enameled film formed on the surface of the fired product, the user should appropriately select according to the taste of the texture of the film. The tendency of the effect of the blending ratio on the texture of the enamel film is as follows. All ratios are weight ratios.
1. 100: 7 with coffee husk: pine ash
When the mixture prepared at this ratio is intermittently charged in the kiln 1 for about 6 hours at a temperature range of 1200 ° C. to 1300 ° C., what is generally called an ash fogging work is completed.
2. 100: 5.5: 1.5 in the blend of coffee husk: pine ash: earth ash
When the mixture prepared at this ratio is intermittently introduced into the kiln 1 at a temperature range of 1200 ° C. to 1300 ° C. for about 6 hours, an Iga-yaki-style ash cover work is completed.
3. 100: 1 with coffee husk: pine ash
If the mixture prepared at this ratio is intermittently put in a wood kiln or climbing kiln for about 6 hours at a temperature range of 1200 ° C to 1300 ° C, Shigaraki style, Shigaraki scarlet style, and Bizen style works will be completed depending on the fabric.

Thus, by blending coffee husk and wood ash as main components at a ratio of ash 1 to 7 with respect to coffee husk 100, adhesion of ash during firing can be adjusted, and the fired product 9 The texture of the holographic coating on the surface of can be brought close to that unique to each ceramic production area.
On the other hand, if only wood ash is thrown into the kiln 1, the wood ash adheres to the fired product in a short time, and even if the input amount is small, it will melt at once in the furnace, resulting in a fired product with little change. . In order to reproduce a fired product similar to that fired in the wood kiln, it is necessary to attach an appropriate amount of wood ash to the fired product so as to be stacked many times. In that sense, mixing in the coffee husk and gradually falling on the fired product in the furnace leads to a natural texture. That is, if only wood ash is put into the kiln 1, it becomes difficult to reproduce the fired product fired in the wood kiln. Moreover, the wood ash melted at a stretch adheres to the furnace wall, resulting in a serious damage to the furnace wall. In addition to coffee husks, we have experimented with sawdust in order to allow wood ash to gradually fall onto the fired product. This is probably because the coffee husk contains a bitter component called tannin, which promotes the adhesion effect of ash.

  The auxiliary fuel made of the mixture of coffee husk and wood ash does not stay in the kiln 1 during firing, and it surely flies in the direction of the chimney 4 on the flame flow, so that it adheres to the fired product 9. Cheap. The coffee husk is porous, has irregularities on the surface, has a light specific gravity, and when given moderate moisture, the wood ash tends to adhere to the surface, making it more efficient to fly wood ash to the back of the kiln 1 He will play a role.

  When mixing coffee husk and wood ash, the most efficient mixture is the mixture of the two finished to the extent that there is no wood ash not associated with the coffee husk. The ratio at this time is ash 7 with respect to the coffee husk 100. Based on this ratio, taking into account the firing time of the kiln 1 and the characteristics of the raw materials to be used, the target surface finish of the fired product 9 and the like, the mixing ratio of coffee husk and ash is set to 100: 1 You can enjoy variations of the work by changing between 7.

It is a vertical side view which shows one embodiment of the kiln for ceramics by this invention. It is a cross-sectional top view which shows one embodiment of the kiln for ceramics by this invention. It is a principal part expansion vertical side view which shows the part of the inlet of the auxiliary fuel which shows one embodiment of the kiln for ceramics by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Kiln 3 Flame inlet 4 Chimney 8 Fired place storage place 6 Entrance 7 Cover lid 9 Fired product

Claims (4)

A flame inlet (3) for introducing a flame into the interior of the kiln (1) surrounded by a refractory, a chimney (4) for exhausting exhaust gas from the kiln (1), and a flame provided inside the kiln (1) In a ceramic kiln having a calcined product storage place (8) for placing a calcined product (9) heated by the furnace, an input port for introducing auxiliary fuel mixed with coffee beans shell and ash to the outer wall of the kiln (1) The kiln for ceramics characterized by having opened (6). The kiln for ceramics according to claim 1, wherein the inlet (6) is openable and closable by a lid (7) made of a refractory material. A flame inlet (3) for introducing a flame into the interior of the kiln (1) surrounded by a refractory, a chimney (4) for exhausting exhaust gas from the kiln (1), and a flame provided inside the kiln (1) And a fired place (8) for placing the fired product (9) heated by the tank, and a charging port (6) into which auxiliary fuel mixed with coffee beans shells and ash is added to the outer wall of the kiln (1). ) Is used to blow the flame of the burner (2) from the flame inlet (3) to the inside of the kiln (1), and the inside of the kiln (1) is heated to a temperature at which the fired product is fired. In this state, the fired product (9) is fired while auxiliary fuel mixed with coffee bean shells and ash is charged into the kiln (1) through the charging port (6). A supplementary fuel for ceramics, characterized by mixing coffee bean shells and ash.

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