JPH0141118Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a capsule for firing a ceramic molded body, which houses a ceramic molded body therein and fires it.

(Prior Art) Generally, a horizontal electric furnace called a tunnel furnace or a gas furnace has been used for firing ceramic molded bodies.

As shown in Fig. 3a, this type of tunnel furnace has a tunnel-shaped furnace body 1 arranged horizontally, and the inside of the furnace body 1 is divided into a preheating zone 1a, a firing zone 1b, and a cooling zone 1c. The preheating zone 1a, firing zone 1b and cooling zone 1c each have a temperature distribution as shown by the polygonal line _h1 in FIG. 3b.

When firing ceramic molded bodies in a tunnel furnace having the above-mentioned configuration, the ceramic molded bodies 2 to be fired are packed vertically or horizontally into a box-shaped firing box 3, as shown in FIG. This firing box 3 is loaded on the base plate 4 as shown in FIG. 3a,
First, it is automatically pushed into the preheating zone 1a of the furnace body 1 as shown by arrow _A1 using a pusher (not shown). After burning the binder (molding aid) in the ceramic molded body 2 in this preheating zone 1a (binder removal process), the base plate 4 is moved to the furnace body 1.
The ceramic molded body 2 is fired at a temperature of 120°C to 135°C for 20 to 30 hours. When this firing is completed, the ceramic molded body 2 is pushed into the cooling zone 1c of the furnace body 1, cooled, and then pulled out from the furnace body 1 as shown by arrow _A2 .

The firing box 3 is made of alumina or mullite material, and if it is reactive with the ceramic molded body 2, a zirconia setter or zirconia powder is spread on the firing box 3, and the ceramic molded body 2 is placed on top of the zirconia setter or zirconia powder. They are packed vertically or horizontally.

By the way, in the ceramic firing apparatus as described above, the ceramic molded body 2 inside the firing box 3 is heat-treated while maintaining the shape packed in the firing box 3, but the center part and the outer peripheral part of the firing box 3 are A temperature difference occurs, and the ceramic molded bodies packed in different positions of the firing box 3 receive different thermal histories. This difference in thermal history is caused by packing the ceramic molded bodies 2 into the firing box 3 in multiple stages and rows, or when the firing box 3
This is noticeable when firing by stacking them in multiple stages.
Large variations occur in the properties of the ceramic molded body 2 after firing.

(Purpose of the invention) The present invention was devised in view of the above-mentioned circumstances in the firing of ceramic molded bodies. The purpose is to provide capsules.

(Structure of the invention) Therefore, in the present invention, at least the capsule body of the cylindrical capsule body and the lids provided at both ends thereof is formed of porous ceramics, and the capsule is transported inside the furnace body. It is characterized by a structure in which it rotates around its axis during the process of firing, and the ceramic molded body housed inside is fluidized and fired continuously.

(Effects of the invention) According to the invention, a type of breathing effect can be obtained due to the air permeability of the porous ceramics during the process in which the ceramic molded body is accommodated in a capsule and is fluidized and transferred inside the furnace body. , the introduction of high-temperature atmosphere into the interior and the discharge of exhaust gas to the outside due to the combustion of the binder are carried out smoothly, heat exchange inside and outside the capsule becomes active, and the atmosphere flows in and out evenly, so a large amount of A ceramic molded body can be fired uniformly, continuously, and efficiently.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIGS. 1a and 1b, the capsule 10 consists of a cylindrical capsule body 8 and lids 10a and 10b at its front and rear ends. This capsule body 8, lid body 10a and 1
0b is a porous material having a large number of pores and made of a material such as mullite, alumina, or silicon carbide.

The capsule body 8 has an outer diameter of approximately 100 mm and a length of 100 mm.
mm to 300mm, its porosity is 20% to 50%
It is preferable that If the porosity is less than 20%, the intended air permeability cannot be obtained, and if it exceeds 50%, the capsule strength will decrease and it cannot be put to practical use.

The lid body 10a at the front end of the capsule body 8 has a central part that is at least 10 mm wide, through which the ceramic molded body 2 accommodated in the capsule 10 can pass.
It has an opening 10c having a diameter of 20 mm to 20 mm. The lid body 10a also has a porosity of 20% to 50%.

The lid 10a is fitted into a portion of the capsule body 8 that is located inside the front end surface and has a larger inner diameter than other portions, and is bonded to the capsule body 8 with a ceramic adhesive 9. This ceramic adhesive 9 is applied to the joint between the lid 10a and the capsule body 8 when the lid 10a is fitted to the capsule body 8, and when the entire body is heated to a high temperature, it melts and joins the lid 10a and the capsule body 8. do.

On the other hand, another lid body 10b of the capsule body 8
has the same shape as the lid 10a, is fitted into a portion of the capsule body 8 whose inner diameter is larger than other portions on the inside of the rear end surface, and is bonded to the capsule body 8 with a ceramic adhesive 9. There is.

The capsule 10 has an opening 10e, for example.
While standing upright with the opening 10c facing upward, the other opening 10c is closed, and the ceramic molded body is filled through the opening 10e using a funnel or the like (not shown). This capsule 10 is supplied to a ceramic firing apparatus as shown in FIG. 2a, for example, and the ceramic molded body 2 inside is heat-treated.

The ceramic firing apparatus shown in Fig. 2a has a base 1
1, which has a furnace body 12 placed on top of the furnace body 12.
A cylindrical furnace core tube 13 is rotatably arranged. This furnace core tube 13 is made of a material such as stainless steel or Inconel for low-temperature processing such as silver baking on the ceramic molded body 2 after firing, and is made of a material such as stainless steel or Inconel for high-temperature processing such as main firing of the ceramic molded body 2. In this case, a material made of mullite, alumina, or even silicon carbide is used.

The furnace core tube 13 has a support roller 14a disposed around the outer circumference of the opening 13a at one end, and an opening 1 at the other end.
3b and a support roller 14b disposed on the outer periphery of the roller 3b. The support roller 14a is
A belt 17 is stretched between a pulley 15a provided on the support shaft 15 and a pulley 16a of a drive motor 16, and is rotationally driven by the drive motor 16.

In order to obtain a sufficient heat insulating effect, the furnace body 12 uses a highly heat insulating material such as a ceramic board having a wall thickness of, for example, 150 mm to 200 mm as its wall material. The length of the furnace body 12 is slightly shorter than the length of the furnace core tube 13 minus the length for installing the support rollers 14a, 14b.

A heater 18 is arranged inside the furnace body 12 so as to surround the furnace core tube 13 . This heater 1
Reference numeral 8 corresponds to the heat treatment pattern of the ceramic molded body 2, and the furnace core tube 13 is arranged so as to exhibit a temperature distribution as shown in FIG. 2b, for example.

The capsule 10, the structure of which has already been explained, has a second
As shown in Figure a, the core tube 1 is
3 through its one end opening 13a.

In this embodiment, the outer diameter of the capsule body 8 is 100 mm.
length 100mm to 300mm, opening 10c, 10e
When the diameter of the core tube 13 is 10 mm to 20 mm, the inner diameter of the core tube 13 is 140 mm, the outer diameter is 155 mm to 160 mm, and the length is 180 mm.
or 2600mm.

The filling amount of the ceramic molded body 2 is 10 capsules.
The ceramic molded body 2 is inserted through the openings 10c and 10e.
To prevent leakage, the level of the ceramic molded body 2 is, for example, 10 mm higher than the periphery of the openings 10c and 10e when the capsule 10 is held horizontally.
It is preferable that it be located at a lower level.

The capsule 10 is pushed through the opening 13a at one end of the core tube 13 by the pusher 20 with its lid body 10a facing forward, as shown in FIG. 13, the other end 13b rotates as the furnace core tube 13 rotates.
move towards.

In this process, the ceramic molded body 2 inside the capsule 10 constantly flows as the capsule 10 rotates, receives heat uniformly from the core tube 13, and is taken out from the other end of the core tube 13 after undergoing a substantially equal thermal history. It will be. Since the capsule 10 is made of porous ceramics, pores (not shown) are formed in the capsule 10 as the capsule 10 rotates and the ceramic molded body inside flows.
A high-temperature atmosphere is introduced through the pores, and the exhaust gas generated by combustion of the binder, etc. in the ceramic molded body 2 is discharged through the pores, so heat exchange inside and outside the capsule 10 is promoted, and the capsule 10
There is no uneven distribution of atmosphere within the chamber, and the ceramic molded body 2 is uniformly and sufficiently sintered.

The fired ceramic molded body 2 is a capsule 10
It can be taken out from the opening 10c of the lid 10a or the opening 10e of the lid 10.

The total residence time of the capsule 10 in the furnace tube 13 is 3 to 5 hours when silver is baked onto the fired ceramic molded body 2, and the binder is not burned during the main firing of the ceramic molded body 2. When the binder is not present, the time is 5 to 10 hours, and when the binder is already burned, the time is 3 to 5 hours. In addition, the rotation speed of the furnace core tube 13 is
The speed should be 0.1rpm to 5rpm.

In the embodiment described above, if the porosity of the ceramics constituting the capsule body 8 and lids 10a and 10b is less than 20%, air cannot be inserted into the capsule 10 and exhaust gas cannot be discharged.
In addition, if the above porosity exceeds 50%, capsule 1
The inner surface of the capsule 10 becomes rough, and the ceramic molded body 2 is easily damaged during firing due to the rotation of the capsule 10, and the strength of the capsule 10 is also reduced.

The porosity of the ceramic can be adjusted by adjusting the amount of binder used when molding the capsule body 8 and lids 10a, 10b.

In the present invention, the ceramic molded body 2 is suitable for firing laminated capacitors and thick plate-shaped ceramics, but it is possible to adjust the rotational speed of the furnace tube 13 and enlarge the openings 10c and 10e of the capsule 10. Therefore, it is possible to heat treat objects with a diameter of 20 mmφ and a wall thickness of about 0.3 mm.

[Brief explanation of the drawing]

FIG. 1a is a longitudinal cross-sectional view of an embodiment of a capsule for firing a ceramic molded body according to the present invention, FIG. 1b is a cross-sectional view taken along the - line of FIG. 1a, and FIG. An explanatory diagram showing the outline, Fig. 2b is a temperature distribution diagram of the furnace tube of the ceramics firing apparatus of Fig. 2a, Fig. 3a is an explanatory diagram of the conventional ceramics firing apparatus, and Fig. 3b is a diagram of Fig. 3a. Figure 4 is a temperature distribution diagram inside the furnace of the ceramic firing equipment shown in Figure 3.
FIG. 3 is a perspective view of a firing box used in the ceramic firing apparatus of FIG. a; 2... Ceramics molded body, 8... Capsule body, 10... Capsule, 10a, 10b... Lid body, 10c, 10e... Opening, 12... Furnace body.

Claims (1)

[Scope of utility model registration request] It is a cylindrical capsule that rotates around the axis during the process of being transferred inside the furnace so that the ceramic molded body housed inside is fluidized and continuously fired. a capsule body, and a lid body provided at both ends of the capsule body and having an opening in the center having a diameter that allows the ceramic molded body to pass through. A capsule for firing a ceramic molded body, characterized in that it is formed of ceramics.