JPH04292782A - Baking furnace - Google Patents

Abstract

PURPOSE:To provide an inexpensive baking furnace which has fast temperature rising and falling speeds, a small energy consumption in a high temperature holding state, can accurately control a temperature at the time of falling the temperature, and obtain uniform temperature in the furnace. CONSTITUTION:A furnace body 22 is formed of an inner insulation layer 23 and an outer insulation layer 24, and cooling air is fed into a space forming member 32 for forming a space 25 to the body at the time of falling a temperature to lower the temperature of the body 22. A heat transfer member 33 connected to the member 32 to transfer heat of the member 32 to the air is provided in the space 25. The heat of a baking space 9 in the body 22 is transferred from the layer 23 to the member 33 in the member 32 through the member 32. When the air is introduced into the space 25 at the time of cooling the body 22, the heat in the body 22 is transferred to the air to be brought to the exterior to cool the body 22.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a firing furnace used for manufacturing ceramic electronic components such as ceramic capacitors.

0002

2. Description of the Related Art In general, tunnel type continuous firing furnaces and batch type firing furnaces are well known as firing furnaces used for manufacturing ceramic electronic parts.

An example of a conventional batch-type firing furnace of this type is shown in FIG. The firing furnace 1 shown in FIG. 8 is of a hearth raising/lowering type, in which a hearth 4 fitted into a lower opening 3 of a furnace body 2 moves up and down with respect to the lower opening 3 of the furnace body 2. A base plate 6 is supported on the upper end of a rod-shaped support member 5 fixed through the hearth 4 with a gap g relative to the floor surface of the hearth 4.
A sagger assembly 7 made up of stacked saggers containing a ceramic molded body (not shown) to be fired is placed. Then, the ceramic molded body is heated by heaters 8, 8, etc. made of silicon carbide (SiC) arranged inside the furnace main body 2, and fired according to a predetermined firing program. During this firing process, inside the firing space 9 inside the furnace body 2,
Atmospheric gas is supplied from an atmospheric gas supply pipe 11 provided on the side wall of the furnace body 2, and cooling air is introduced in the process of cooling the furnace body 2. Furthermore, the exhaust gas generated in the firing space 9 during the firing process passes through the gap g between the base plate 6 and the hearth 4 through the exhaust port 12 formed in the hearth 4, and passes through the exhaust port 12 formed in the hearth 4 to the outside of the furnace body 2. is discharged.

0004

By the way, in the conventional batch type firing furnace 1 having the above-mentioned configuration, the heat escaping from the inside of the furnace body 2 to the outside of the furnace body 2 is minimized so that the heaters 8, 8 ,... In order to reduce the power consumption of the furnace body 2, the heat insulating layer made of the heat insulating material constituting the furnace body 2 is made thicker.After the temperature inside the furnace body 2 is maintained at a predetermined high temperature,
Even when the power to the heaters 8, 8, . . . is turned off, the temperature inside the furnace body 2 does not drop easily, resulting in a problem that the temperature drop time becomes long and the operating rate of the furnace decreases.

On the other hand, in order to shorten the cooling time of the furnace body 2, if the heat insulating layer constituting the furnace body 2 is made thinner,
The amount of heat dissipated from the furnace wall increases, and the power consumption of the heaters 8, 8, . . . increases. Furthermore, if the temperature of the furnace body 2 is rapidly increased or decreased, the temperature gradient within the heat insulating layer of the furnace body 2 becomes large, the temperature uniformity within the furnace body 2 deteriorates, and all the coatings within the furnace body 2 become Maintaining a uniform temperature condition for the fired product,
There was also the problem that it was difficult to raise and lower the temperature.

In order to solve these problems in the conventional firing furnace, a firing furnace 21 having a configuration as shown in FIG.
has also been proposed. The firing furnace 21 shown in FIG.
2 is composed of an inner heat insulating layer 23 and an outer heat insulating layer 24 disposed outside of the inner heat insulating layer 23. When the temperature drops, cooling air is sent into the space defining member 26 that defines a space 25 between the inner heat insulating layer 23 and the outer heat insulating layer 24 to cool the furnace body 2.
2. The time for the internal temperature to drop is shortened.

In the firing furnace shown in FIG. 9, the space defining member 26 that defines the space 25 between the inner heat insulating layer 23 and the outer heat insulating layer 24 constituting the furnace body 22 has a high temperature. It needs to be constructed using an expensive superalloy with strength, which not only increases the material cost of the firing furnace 22, but also makes it difficult to cool the furnace body 22 since the interior of the space-defining member 26 is just a space. Efficiency is not very high,
There was also a problem in that heat convection occurred in the vertical direction inside the space 25 and the temperature within the firing space 9 became non-uniform.

[0008] The object of the present invention is to have a high temperature increase rate and a temperature decrease rate, consume less energy in a high temperature holding state, and enable highly accurate temperature control when lowering the temperature.
It is an object of the present invention to provide a low-cost firing furnace that can obtain a uniform temperature inside the furnace.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that a furnace body in which a material to be fired is housed and fired is made up of an inner heat insulating layer and an outer heat insulating layer disposed outside the inner heat insulating layer. A firing furnace configured to lower the temperature inside the furnace main body by sending cooling air into a space defining member that defines a space between the inner heat insulating layer and the outer heat insulating layer when the temperature falls, The present invention is characterized in that a heat transfer member is provided inside the space, the heat transfer member being connected to the space defining member and transmitting the heat of the space defining member to the cooling air.

0010

[Operation] Heat from the firing space inside the furnace body is transferred from the inner heat insulating layer to the heat transfer member inside the space defining member. When cooling air is introduced into the space inside the space defining member during cooling of the furnace body, the cooling air contacts the heat transfer member with a large contact area, and heat is transferred from the heat transfer member to the cooling air. It will be done. As a result, the heat inside the furnace body is transferred to the cooling air and discharged to the outside, thereby cooling the furnace body.

[0011]

According to the present invention, the space defined by the space-defining member has a heat transfer member inside, and the heat in the firing space inside the furnace body passes through the space-defining member from the inner heat insulating layer. Since heat is transferred, when cooling air is introduced into the space inside the space defining member when cooling the furnace body, the cooling air contacts the heat transfer member with a large contact area, and heat is transferred from the heat transfer member to the cooling air. Heat is transferred and rapid cooling is possible without changing properties.

Furthermore, since the space-defining member is reinforced by the internal heat transfer member, it is possible to use materials that are lower in strength and cost than materials such as superalloys, and the cost of the firing furnace can be reduced. can be lowered.

Further, according to the present invention, since the heat transfer member is disposed inside the space defining member, there is no occurrence of heat convection in the vertical direction, and the temperature in the firing space inside the furnace body is reduced. Uniformity can be ensured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a longitudinal section of an embodiment of a batch type firing furnace according to the present invention. In the firing furnace 21 described in FIG. 9, the space defining member 32 of the furnace body 22 is made of a heat-resistant alloy material whose material cost is lower than that of a superalloy with high heat-resistant strength. component 32
A large number of heat dissipating fins 33, 33, . . . are attached as heat transfer members. Note that in FIG. 1, parts corresponding to those in FIG. 9 are shown with corresponding symbols, and duplicate explanations will be omitted.

Each of the radiation fins 33 is connected to the space defining member 32.
It is made of the same heat-resistant alloy material as , has a substantially constant width in the horizontal direction, and is provided so as to bridge the portions of the space defining member 32 that are in contact with the inner heat insulating layer 23 and the outer heat insulating layer 24 . Each of the radiation fins 33 is arranged inside the space defining member 32 so that the phases of the radiating fins 33 that are adjacent to each other are different from each other, as shown in FIG.

In the space 25 of the space defining member 32 of the furnace body 22, as shown in FIG. Each is open.

With such a configuration, the radiation fins 23
Since it bridges the portion of the space defining member 32 that is in contact with the inner heat insulating layer 23 and the outer heat insulating layer 24, it has the function of reinforcing the strength of the space defining member 32. Therefore, as the space defining member 32, it is possible to use a heat-resistant alloy that is lower in strength and cost than a superalloy. Also, when cooling the furnace body 22, the cooling air inlet 3
4 into the space 25 in the space defining member 32 of the furnace body 22, the cooling air flows as shown by the arrow A1 in FIG.
, flows horizontally within the space 25 in the direction indicated by A3, and in the process comes into contact with a large number of radiation fins 33, 33, . After receiving the heat transferred to the member 32, it is taken out of the space 25 through the discharge port 35. Thereby, the furnace body 22 is quickly cooled. As mentioned above, the cooling air flows along the radiation fins 33, 33, . Temperature uniformity within the firing space 9 of the furnace body 22 is ensured when the temperature decreases.

As shown in FIG. 3, the cooling air is supplied to the furnace body 22.
As shown in FIG.
The openings 36 provided at each corner of the furnace body 22 can be divided by a partition wall 37 to serve as an inlet 38 and an outlet 39 for cooling air. The opening 36 provided in
8 may also be provided.

Next, two other embodiments of the firing furnace according to the present invention are shown in FIGS. 6 and 7. A firing furnace 41 shown in FIG. 6 is constructed by connecting a heat transfer member 42 having a honeycomb structure made of a heat-resistant material such as ceramic to the space defining member 32 in place of the heat radiation fins 33 in the firing furnace 31 shown in FIG. , is arranged in the space 25 inside the space defining member 32. Furthermore, in the firing furnace 45 shown in FIG. 7, a heat transfer member 43 having a lattice structure made of a heat-resistant material such as ceramic is connected to the space defining member 32 in place of the radiation fins 33 in the firing furnace 31 of FIG. It is arranged in the space 25 inside the space defining member 32. Note that in FIGS. 6 and 7, parts corresponding to those in FIG. 1 are denoted by corresponding symbols, and redundant explanations will be omitted.

The firing furnaces shown in FIGS. 6 and 7 can also produce the same effects as the firing furnace shown in FIG. 1.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing the structure of an embodiment of a firing furnace according to the present invention.

FIG. 2 is a cross-sectional view of the firing furnace of FIG. 1 taken along line BB.

FIG. 3 is an explanatory diagram of circulation of cooling air in the firing furnace of FIG. 1;

FIG. 4 is an explanatory diagram of circulation of cooling air in the firing furnace of FIG. 1;

FIG. 5 is an explanatory diagram of circulation of cooling air in the firing furnace of FIG. 1;

FIG. 6 is a longitudinal sectional view showing the structure of another embodiment of the firing furnace according to the present invention.

FIG. 7 is a longitudinal sectional view showing the structure of yet another embodiment of the firing furnace according to the present invention.

FIG. 8 is a longitudinal cross-sectional view showing the structure of a conventional firing furnace.

FIG. 9 is a longitudinal sectional view showing the structure of another conventional firing furnace.

[Explanation of symbols]

4 Hearth 7 Box assembly 8 Heater 9 Baking space 11 Atmosphere gas supply pipe 12 Exhaust port 22 Furnace body 23 Inner insulation layer 24 Outer insulation layer 25 Space 31 Space defining member 33 Heat dissipation fin 34 Introduction port 35 Discharge port 36 Opening 37 Partition wall 38 Introduction port 39 Discharge port 42 Heat transfer member 43 Heat transfer member

Claims (1)

[Claims] Claim 1: A furnace body in which a material to be fired is housed and fired is composed of an inner heat insulating layer and an outer heat insulating layer disposed outside the inner heat insulating layer, and when the temperature decreases, the furnace body is made up of an inner heat insulating layer and an outer heat insulating layer disposed outside the inner heat insulating layer. A firing furnace configured to lower the temperature inside the furnace body by sending cooling air into a space defining member that defines a space, the firing furnace having a space defining member connected to the space defining member inside the space. A firing furnace characterized by comprising a heat transfer member that transfers heat from the formed member to the cooling air.