JPH03217784A - Batch type calcining furnace - Google Patents

Abstract

PURPOSE:To increase the rate of operation and permit correct temperature control upon reducing temperature by a method wherein a space is formed between an inside heat insulating layer and an outside heat insulating layer and cooling fins the fixed to the inside heat insulating layer, opposed to the outside heat insulating layer, so as to be opposed to the outside heat insulating layer while an air supplying means and an air discharging means are communicated with the space between the inside and outside heat insulating layers. CONSTITUTION:Works to be calcined, which are received in respective boxes in a box assembly 6, are heated and calcined by a heater. Upon increasing a temperature in a furnace body 12, the convection of air in a space 16 is suppressed by the hindrance of the fin parts 15a of cooling fins 15 and a temperature difference between the upper part and the lower part of the furnace body 12 is reduced. When high-temperature keeping in the furnace body 12 is finished, valves 17, 22 are opened and air is sent into the space 16 from a main pipe 18 through branched pipes 19 to contact with the fin parts 15a of the cooling fins 15 and absorb heat from the furnace body 12 through an inside heat insulating layer 13, then, the air cools the furnace body 12 and is discharged to the outside of a house through exhaust gas discharging pipes 21. A temperature in the furnace body 12 is reduced without increasing the temperature of a room, in which this calcining furnace 11 is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a batch-type firing furnace mainly used for manufacturing ceramic electronic components such as ceramic capacitors.

(Prior Art) Generally, a tunnel-type continuous firing furnace or a batch-type firing furnace is used for firing ceramic molded bodies used for manufacturing ceramic electronic components.

FIG. 2 shows a longitudinal cross section of an example of a conventional kiln of this kind, and FIG. 3 shows a cross section thereof along line 1-1.

The above firing furnace is a batch type firing furnace in which the hearth moves up and down.
A hearth 3 of a furnace body 2 supported on a hearth 3 has an opening 4,
It has an elevating hearth 5 which fits into this frontage 4 and which moves up and down with respect to this frontage 4 .

This elevating hearth 5 is raised and lowered relative to the opening 4 by means such as hydraulic pressure or screws. This elevating hearth 5
A box assembly 6 consisting of stacked boxes containing objects to be fired (not shown) is placed on top of the box. Although not specifically shown in the drawings, the objects to be fired are arranged in a parallel grid shape through a U-shaped heater suspended inside the furnace body 2 from the ceiling 2a of the furnace body 2 or through the furnace wall 2b. The material is heated by a rod-shaped silicon carbide (SiC) heater, and is fired according to a firing profile as indicated by a dotted line 1111 in FIG. 4, for example.

(Problems to be Solved by the Invention) Incidentally, in the firing furnace having the above-mentioned configuration, it is conventional to minimize the heat escaping from the inside of the furnace body 2 to the outside of the furnace body 2, and to prevent the temperature rise inside the furnace. In order to increase speed and reduce power consumption, the heat insulating material layer constituting the furnace body 2 was made thicker. For this reason, even if the heater is turned off after the temperature inside the furnace body 2 is maintained at a high temperature of T'C, the temperature inside the furnace body 2 does not drop easily, as shown by the solid line m in Fig. 4. Otherwise, the temperature down time will be longer. As described above, in the above conventional firing furnace, it takes time for the temperature inside the furnace body 2 to fall when the temperature is lowered, so it is difficult to accurately control the temperature inside the furnace body 2 according to the firing profile when the temperature is lowered. There was such a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hanochi-type firing furnace that has a high operating rate and allows accurate temperature control during cooling.

(Means for Solving the Problems) Therefore, the present invention has a vertical furnace body in which the object to be fired is housed and fired, and the furnace wall portion of the furnace body has an inner heat insulating layer and an outer heat insulating layer. A space is formed between the inner heat insulating layer and the outer heat insulating layer, and the cooling fin is placed on the opposite surface of the inner heat insulating layer that faces the outer heat insulating layer in the space, and the fin portion is on the outside. It is characterized in that it is fixed so as to protrude toward the heat insulating layer, and an air supply means and an air discharge means are communicated with the space.

(Function) When the temperature of the furnace body rises, the air supply means and air discharge means are closed, and three heat insulation layers are formed in the furnace body, consisting of an inner heat insulation layer, an outer heat insulation layer, and an air layer in the space between them. As a result, the temperature inside the furnace body rises rapidly.

On the other hand, when the temperature inside the furnace body is decreasing, air is introduced into the space between the inner heat insulating layer and the outer heat insulating layer from the air supply means. The air introduced into this space contacts the cooling fins, absorbs heat from the inner heat insulating layer, cools the inner heat insulating layer, and is discharged from the air exhaust means. This shortens the time required for the furnace body to cool down.

(Effects of the Invention) According to the present invention, when the temperature inside the furnace body rises, the air introduced into the space between the inner heat insulation layer and the outer heat insulation layer of the furnace body functions as a heat shielding layer. , heat escaping from the furnace body to the outside of the furnace body is blocked, the temperature inside the furnace body is rapidly raised, and the thermal efficiency of the firing furnace is also improved.

Further, according to the present invention, the cooling fins protruding from the inner heat insulating layer toward the outer heat insulating layer prevent air convection in the space between the inner heat insulating layer and the outer heat insulating layer. The temperature difference between the two processes is reduced, and products with less variation in quality can be obtained.

Furthermore, according to the present invention, when the temperature inside the furnace body falls, the air introduced into and discharged from the space between the inner heat insulation layer and the outer heat insulation layer that constitute the furnace body contacts the cooling fins, and Since heat is absorbed and the inner heat insulating layer is cooled, the temperature inside the furnace body at the time of cooling can be accurately controlled by energizing the heater even during this temperature drop.

Furthermore, according to the present invention, by cooling the furnace body with air, the time required to cool the inside of the furnace body to a required temperature is shortened, so that the operating rate of the furnace is also improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

The vertical cross section of one embodiment of the batch type firing furnace according to the present invention is shown in the first example.
As shown in the figure.

The batch type firing furnace 11 has a furnace wall portion 12a of the furnace body 2.
consists of an inner heat insulating layer 13, an outer heat insulating layer 14, and cooling fins 15.

The furnace wall portion 12a has an inner heat insulating layer 13 made of a heat insulating hoard with a thickness of about 30+n+n and an outer heat insulating layer 14 made of a heat insulating port with a thickness of about 50 mm.
They are arranged at intervals of 00 mm. Therefore, a space I6 having a thickness of 100 mm is formed between the inner heat insulating layer l3 and the outer heat insulating layer 14.

The cooling fins 15 are fixed to the opposing surface of the inner heat insulating layer 13 facing the outer heat insulating layer 14 within the space 16, and each fin portion 15a thereof protrudes toward the outer heat insulating layer 14. The cooling fins 16 are made of a heat-resistant material such as Inkoru.

The furnace body 12 is supported on a hearth 3 supported on a pedestal l similar to the batch type firing furnace described in FIG.

The space 15 inside the side wall portion 12g of the furnace body 12 communicates with a plurality of branch vibes 19 branching from a main pipe l8 having an electromagnetic hull 17. Above branch pipe 1
9 and the main pipe 18 constitute an air supply means.

On the other hand, the ceiling portion 12b of the furnace body 12 is provided with an exhaust gas exhaust vibe 2I that communicates with the space 15 inside the side wall portion 12a of the furnace body 12.

This exhaust gas discharge vibrator 21 constitutes an exhaust gas discharge means, and is provided with an electric pole valve 22 in the middle thereof.

The electromagnetic valve 17 and the electric pole valve 22 are opened and closed by electric signals from a control device (not shown) that controls the firing furnace 11.

The main pipe 18 of the air supply means is connected to an air supply device (not shown). Further, each of the exhaust gas exhaust pipes 21 is connected to an exhaust pipe (not shown) leading to the outside of the building (not shown) in which the main firing furnace 11 is installed.

Inside the furnace body 12, although not specifically shown, a U-shaped or rod-shaped silicon carbide heater similar to the firing furnace of FIG. 3 is arranged.

On the elevating hearth 5 of the bunch type firing furnace 11, boxes containing objects to be fired (not shown) are stacked, similar to the hatch type firing furnace shown in FIGS. 2 and 3. A box assembly 6 made of plastic is placed thereon.

With such a configuration, the objects to be fired accommodated in each box in the box assembly 6 placed on the elevating hearth 5 are heated and baked by the heater. When the temperature inside the furnace body 12 increases, the electromagnetic valve 17 and the electric ball valve 22 of the firing furnace 1l are closed, and the inner heat insulating layer 13 and the space 1 are closed.
Heat escape from the furnace body 12 is suppressed by a total of three heat insulating layers including the air layer in the furnace body 6 and the outer heat insulating layer 14. As a result, heat radiation loss is reduced and the temperature of the furnace body 12 is rapidly raised. In this case, the air in the space 15 is blocked by the fin portions 15a of the cooling fins 15, and convection is suppressed.
The temperature difference between the upper and lower parts of the furnace body 12 also becomes smaller.

When the temperature inside the furnace body 12 is maintained at T'C shown in FIG. From the supply device, air is sent from the main pipe 18 through the branch pipes 19 to the space 16 in the furnace wall portion 12a, and these branch pipes 1
9 into the space 16. This air contacts the fin portions 15a of the cooling fins 15 in the space 16, absorbs heat from inside the furnace body 12 through the inner heat insulating layer l3, cools the furnace body 12, and cools the furnace body 12. The air is collected in the air discharge pipe 21 of the section 12b, and is discharged outdoors by the exhaust gas discharge vibrator 21. As a result, the main firing furnace 1
Furnace body 12 without raising the temperature of the room in which it is installed
It can lower the temperature inside.

In the above example, if the object to be fired needs to be fired in a protective atmosphere gas, the same atmosphere gas is
Before being introduced into the furnace body 12, the material may be introduced into the space 16 and preheated before being introduced into the furnace body 12.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a batch-type firing furnace according to the present invention, FIG. 2 is a vertical cross-sectional view of a conventional Banochi-type firing furnace, and FIG. 3 is a vertical cross-sectional view of the batch-type firing furnace of FIG. - A cross-sectional view taken along line ■. FIG. 4 is an explanatory diagram of the firing temperature profile of a conventional batch-type firing furnace and actual temperature changes in the furnace. DESCRIPTION OF SYMBOLS 1... Frame, 3... Hearth, 4... Opening, 5... Elevating hearth 6... Box assembly, 11... Batch type firing furnace 12
...Furnace body (1 2a...furnace wall part, 12b...ceiling part), 13.Inner heat insulation layer, 14...Outer heat insulation layer 5.
...Cooling fin (1 5a...Fin part) 6...Space, 17...Solenoid valve, 18...Main pipe, 9. Branch pipe, 21 - Exhaust gas discharge pipe, 2...Electric hall valve. Patent applicant Murata Manufacturing Co., Ltd. Agent
Patent attorney Haka Aoyama Figure 4 1 ← Time ~ 0)

Claims (1)

[Claims] (1) It has a vertical furnace body in which the material to be fired is housed and fired, and the furnace wall portion of this furnace body consists of an inner heat insulating layer, an outer heat insulating layer, and cooling fins, and the inner heat insulating layer and A space is formed between the cooling fins and the outer heat insulating layer, and the cooling fins are fixed to the opposing surface of the inner heat insulating layer facing the outer heat insulating layer in the space so that the fin portions protrude toward the outer heat insulating layer, and A batch type firing furnace characterized in that an air supply means and an air discharge means are communicated with a space.