JPH07294122A - Ceramic green sheet drying apparatus and ceramic green sheet drying method - Google Patents

Abstract

PURPOSE:To reduce internal stress of a ceramic green sheet and defective shape such as warpage produced upon burning of the ceramic green sheet by efficiently and evenly drying the ceramic green sheet formed by means of an extrusion molding method. CONSTITUTION:A ceramic green sheet drying apparatus 21 comprises a drying room, in which a ceramic green sheet S is dried, and convey means 3 for conveying the ceramic green sheet into the drying room. The drying room has a microwave heating zone for microwave heating the ceramic green sheet S conveyed by the convey means 3, which microwave heating zone 26 is provided with a hot-air blowing heating device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic green sheet drying apparatus and a ceramic green sheet drying method for uniformly drying the inside and upper and lower surfaces of a ceramic green sheet.

[0002]

2. Description of the Related Art A conventional ceramic green sheet drying apparatus and a ceramic green sheet drying method will be described with reference to FIG. 3, taking a ceramic green sheet drying apparatus using external heating as an example. The ceramic green sheet drying device 1 includes a drying chamber 2 and a transporting unit 3 that allows the ceramic green sheet S to pass through the drying chamber 2 in the horizontal direction.

The drying chamber 2 has a through hole 4 in the horizontal direction,
Above the through hole 4, there is an external heating zone 8 in which an external heating heater 7 composed of, for example, an infrared heating heater is installed.

The transport means 3 comprises an inlet 9 and an outlet 1 of the drying chamber 2.
0 has rotating rollers 11 and 12, and a belt 13 is provided between them.
Is a belt conveyor that moves the belt 13 in the predetermined direction X by rotating the rotating roller 11 or 12 using the motor M. The inlet 9 of the drying chamber 2
The ceramic green sheet S can be transferred from the through to the outlet 10 through the through hole 4.

A method of drying the ceramic green sheet S using the ceramic green sheet drying apparatus 1 having the above structure will be described.

The ceramic green sheet S before drying is
The ceramic green sheet drying apparatus 1 is placed on the belt 13 on the inlet 9 side. The ceramic green sheet S on the belt 13 has a through hole 4 as the belt 13 rotates.
It is transferred in the X direction. Then, when passing through the external heating zone 8, the ceramic green sheet S is dried from the upper surface portion by the external heating and is transferred to the outlet 10 side.

The ceramic green sheet dryer 1
The ceramic green sheet can be dried even when the heating means is microwave heating or hot air supply heating instead of external heating.

[0008]

However, the conventional apparatus and method for drying a ceramic green sheet have the following problems.

1. Since the through-hole of the drying chamber has a conveyer means such as a belt for transferring the ceramic green sheet under the through-hole, the external heater is installed above the through-hole in terms of heating efficiency. Therefore, the ceramic green sheet passing through the drying chamber and being dried has a difference in drying due to a temperature difference between the upper surface side and the lower surface side, and this difference causes internal stress to remain in the ceramic green sheet. Become. When the ceramic green sheet having the internal stress is fired, the ceramic may be warped.

2. In the case of external heating, the ceramic green sheets are dried inward in order from the upper surface, so it takes a long time to dry and the drying efficiency is poor.

3. Since the through hole of the drying chamber enhances heating efficiency, it is difficult to increase the cross-sectional area (volume of the through hole of the drying chamber). Therefore, vaporized substances such as water vapor generated by the drying of the ceramic green sheet by external heating are filled in the through holes having a small cross-sectional area, and it takes a long time to dry and the drying efficiency is poor.

4. When the ceramic green sheets are dried with warm air instead of the external heating, the ceramic green sheets are sequentially dried inward from the upper surface portion in the same manner as the conventional external heating, so that the drying efficiency is poor.

5. When the ceramic green sheet is dried by microwave heating instead of external heating, vaporized substances such as water vapor generated when the ceramic green sheet is dried by microwave heating are generated through the through holes as in the conventional external heating. Since the inside was not sufficiently ventilated, the inside of the through hole was filled with dew condensation, and it took a long time to dry. Further, in the microwave heating, the ceramic green sheet is heated from the inside, but when the electric power is increased to accelerate the drying, the solvent may bump inside the ceramic green sheet and the ceramic green sheet may explode.

The object of the present invention is to solve the above-mentioned problems. For example, by efficiently and uniformly drying a ceramic green sheet produced by an extrusion molding method, the ceramic green sheet The purpose is to reduce internal stress and reduce shape defects due to deformation such as warpage when firing a ceramic green sheet.

[0015]

In order to achieve the above object, a ceramic green sheet drying apparatus of the present invention comprises a drying chamber for drying the ceramic green sheet and a transport for transferring the ceramic green sheet in the drying chamber. Means and the drying chamber has a microwave heating zone for microwave heating the ceramic green sheet transferred by the conveying means, and the microwave heating zone is provided with a warm air supply heating device. To do.

Further, a drying chamber for drying the ceramic green sheet and a conveying means for moving the ceramic green sheet in the drying chamber are provided, and the drying chamber includes the ceramic green sheet transferred by the conveying means. A microwave heating zone for microwave heating and an external heating zone for heating from the outside are provided, and the microwave heating zone and the external heating zone are provided with a warm air supply heating device.

The conveying means is provided with means for inverting the upper and lower surfaces of the ceramic green sheet.

Further, the conveying means is composed of at least two upper and lower stages, and the conveying directions of the upper and lower two stages are opposite to each other, and the ceramic green sheet is unidirectional by the upper conveying means. The upper and lower surfaces of the ceramic green sheet are reversed by being transferred to the lower transfer means from this transfer means at the final end of the upper transfer means, and transferred in the reverse direction by the lower transfer means. It is characterized by

Further, a drying chamber for drying the ceramic green sheet and a transporting means for transporting the ceramic green sheet in the drying chamber are provided, and the drying chamber transports the ceramic green sheet transported by the transporting means. It has a microwave heating zone for microwave heating and an external heating zone for heating from the outside, the microwave heating zone and the external heating zone are provided with a warm air supply heating device, and the conveying means is composed of at least two stages above and below. It is characterized by being.

The above-mentioned drying chamber is characterized by having a cooling zone near the outlet of the drying chamber.

The method for drying a ceramic green sheet according to the present invention is characterized in that the ceramic green sheet transferred by the transfer means for transferring the ceramic green sheet is heated by microwave and heated by supplying hot air to dry it. .

Further, the ceramic green sheet transferred by the transfer means for transferring the ceramic green sheet is microwave-heated and is heated and supplied with warm air to be dried, and then externally heated and heated and supplied with warm air. It is characterized by being dried.

The ceramic green sheet is dried by inverting its upper and lower surfaces during the transportation for drying.

Further, the ceramic green sheet is
At least two upper and lower conveying means are used, the ceramic green sheet is heated on the upper conveying means, and when being transferred to the lower conveying means, the upper and lower surfaces of the ceramic green sheet are inverted so that the upper conveying means is on the lower conveying means. And heating the ceramic green sheet.

[0025]

According to the present invention, in the ceramic green sheet drying apparatus and the ceramic green sheet drying method having the heating zone having the above-mentioned structure, the warm air supplied by the hot air is heated by the microwave heating or the external heating by the ceramic green sheet. The evaporate that evaporates is discharged from the drying chamber, so that the drying efficiency is increased. Also, by using microwave heating and / or external heating together with hot air supply heating, the ceramic green sheet can be dried first from the inside and then the upper surface portion, and the drying can be made efficient. You can At the time of this drying, since the evaporation product generated by microwave heating is discharged from the drying chamber together with the warm air, it is possible to prevent the dew condensation occurring inside the drying chamber.

Then, the upper and lower surfaces of the ceramic green sheet are more uniformly dried by reversing the upper surface side and the lower surface side of the ceramic green sheet during transfer in the drying chamber, and stress remains inside the ceramic green sheet. Prevent that.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. However, the same parts as those of the above-described conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

Ceramic green sheet dryer 21
Is composed of upper and lower two-stage drying chambers 22a and 22b and transporting means 3 and 3 for transferring the ceramic green sheet S horizontally in the drying chambers 22a and 22b.

Drying chamber 2 provided at the upper stage of the drying device 21
2a has a through hole 24a in the horizontal direction.
It has a microwave heating zone 26 in which a microwave heating device 25 is installed above 4a. Also, the drying room 22
A hot air supply / heating device (not shown) is installed in a, and hot air from the hot air supply / heating device is supplied to the through hole 24a by, for example, a fan (not shown) provided in the drying chamber 22a. It flows from the vicinity of the outlet 30a on the right side toward the inlet 29a on the left side and is discharged from the inlet 29a. The drying chamber 22b provided at the lower stage of the drying device 21 has a through hole 24b in the horizontal direction, and the drying chamber 22b has a warm air supply heating device (not shown).
Is installed, and hot air supplied from the same is supplied from the vicinity of the outlet 30b on the left side of the drying chamber 22b to the inlet 29 on the right side of the drying chamber 22b.
It is made to flow in the b direction and discharged from the inlet 29b.

The conveying means 3 provided in the drying chamber 22a is
The rotary roller 1 is installed at the inlet 29a and the outlet 30a of the drying chamber 22a.
1 and 12, a belt 13 is stretched between them, and the rotating roller 11 or 12 is rotated by the motor M to rotate the belt 13 in the X direction. Through hole 2 from 29a
The ceramic green sheet S can be transferred from the left to the right through the 4a to the outlet 30a. The transporting means 3 provided in the drying chamber 22b rotates the belt 13 in the Y direction in the same manner as the transporting means 3 in the upper stage, and passes from the inlet 29b of the drying chamber 22b through the through hole 24b to the outlet 30b. The ceramic green sheet S can be transferred from right to left.

A method of drying the ceramic green sheet S using the ceramic green sheet drying device 21 having such a configuration will be described.

The ceramic green sheet S before drying is
Upper entrance 2 of the ceramic green sheet dryer 21
It is placed on the belt 13 on the 9a side. The ceramic green sheet S has a through hole 24 as the belt 13 rotates.
It is transferred in the X direction in a. When passing through the microwave heating zone 26, the ceramic green sheet S is dried from the inside by the microwave heating, and is also dried from the surface A which is the upper surface side by the warm air from the warm air supply heating device. To be done. Evaporated matter from the ceramic green sheet S generated at that time is caused to flow in the W direction in the drying chamber 22a along with the flow W of warm air, and is discharged from the inlet 29a.

Then, the ceramic green sheet S is transported to the outlet 30a side while being dried, and the ceramic green sheet S reaching the end of the belt 13 falls vertically downward and is transported from the right to the left in the lower stage. Ride on the right end of belt 13 of means 3. When the transfer means 3 moves from the upper transfer means 3 to the lower transfer means 3, the surface A of the ceramic green sheet S being transferred in the through hole 24a of the upper step becomes the lower surface side of the transfer in the through hole 24b of the lower step. .
That is, the upper and lower surfaces of the ceramic green sheet S transferred from the drying chamber 22a to the drying chamber 22b are inverted.

The ceramic green sheet S whose upper and lower surfaces are reversed is carried in through the inlet 29b of the drying chamber 22a, and the upper surface becomes the surface opposite to the A surface by the warm air from the warm air supply heating device during the transfer through the through hole 24b. It is discharged from the outlet 30b while being dried from the B side.

Next, a second embodiment of the present invention will be described with reference to FIG. Ceramic green sheet dryer 41
Includes the drying chambers 42a, 42b, 42c and the ceramic green sheets S in the upper, middle, and lower three stages.
It comprises transporting means 3, 3, 3 for horizontally moving the inside of c.

Drying chamber 4 provided at the upper stage of the drying device 41
2a has a through hole 44a in the horizontal direction, and the through hole 4a
Next to the microwave heating zone 46 in which the microwave heating device 25 is installed above 4a and the microwave heating zone 46, for example, a far-infrared heater or a near-infrared heater installed above the drying chamber, and installed around the drying chamber. It also has an external heating zone 48a in which an external heating heater 47a such as a resistance heater is installed. A hot air supply / heating device (not shown) is installed in the drying chamber 42a, and the hot air supplied from the heating device is the same as in the first embodiment described above.
Flow from the vicinity of the outlet 50a on the right side of a toward the inlet 49a on the left side and is discharged from the inlet 49a.

Drying chamber 4 provided in the middle stage of the drying device 41
2b has a through hole 44b in the horizontal direction, and has an external heating zone (not shown) in which an external heater 47b is installed. Further, a warm air supply / heating device (not shown) is installed in the drying chamber 42b, and the warm air supplied from the heating device is directed from the vicinity of the outlet 50b on the left side of the drying chamber 42b to the inlet 49b on the right side in the same manner as described above. Flowed in W direction, entrance 49b
Emitted from.

Drying chamber 4 provided at the lower stage of the drying device 41
2c has a through hole 44c in the horizontal direction and an external heating zone (not shown) in which an external heater 47c is installed. Further, a warm air supply / heating device (not shown) is installed in the drying chamber 42c, and the warm air supplied from the heating device is from the vicinity of the outlet 50c on the right side of the drying chamber 42c to the inlet 49c on the left side in the same manner as described above. Flowed in W direction, entrance 49c
Emitted from.

The conveying means 3 provided in the drying chamber 42a is
Similar to the above, it is a belt conveyor that rotates and moves the belt 13 in the X direction, and can transfer the ceramic green sheet S in the X direction from the inlet 49a of the drying chamber 42a through the through hole 44a to the outlet 50a. . The conveyance means 3 provided in the middle-stage drying chamber 42b includes the drying chamber 42b.
The ceramic green sheet S can be transferred in the Y direction from the inlet 49b to the outlet 50b through the through hole 44b. The conveying means 3 provided in the lower drying chamber 42c can transfer the ceramic green sheet S in the X direction from the inlet 49c of the drying chamber 42c through the through hole 44c to the outlet 50c.

A method for drying the ceramic green sheet S using the ceramic green sheet drying device 41 having such a configuration will be described.

The ceramic green sheet S before drying is
Ceramic green sheet dryer 41 upper entrance 4
It is placed on the belt 13 on the 9a side. The ceramic green sheet S has a through hole 44 as the belt 13 rotates.
It is transferred in the X direction in a. When passing through the microwave heating zone 46, the ceramic green sheet S is dried from the inside by the microwave heating, and is also dried from the upper surface A surface by the warm air from the warm air supply heating device. To be done. Evaporated matter from the ceramic green sheet S generated at that time is caused to flow in the W direction in the drying chamber 42a along with the flow W of the warm air supplied from the warm air supply heating device, and is discharged from the inlet 49a. Next, when passing through the external heating zone 48a, the ceramic green sheet S is mainly subjected to A by the external heating and the hot air supply heating.
The surface is dried. Evaporated matter from the ceramic green sheet S generated at that time is caused to flow in the W direction in the drying chamber 42a along with the flow W of warm air supplied from the warm air supply heating device, and is discharged from the inlet 49a.

Then, the ceramic green sheet S is transferred to the outlet 50a side while being dried, and the ceramic green sheet S reaching the end of the belt 13 drops vertically downward, and the middle transfer step of the transfer means 3 is reversed. Belt 13
Get on the right end of the road. When the transfer means 3 in the upper stage moves to the transfer means 3 in the middle stage, the upper and lower surfaces of the ceramic green sheet S transferred from the drying chamber 42a to the drying chamber 42b are reversed, and the surface A is the lower surface side.

The ceramic green sheet S whose upper and lower surfaces are turned upside down is conveyed to the entrance 4 of the drying chamber 42b by the conveying means 3 in the middle stage.
It is carried in from 9b and transferred in the Y direction in the through hole 44b. When passing through the external heating zone 48b of the through hole 44b, the ceramic green sheet S is mainly on the upper surface side which is the surface opposite to the A surface due to the external heating and the hot air supply heating.
The surface is dried. Evaporates from the ceramic green sheet S generated at that time are flowed in the W direction in the drying chamber 42b along with the flow W of the warm air supplied from the warm air supply heating device, and are discharged from the inlet 49b.

The ceramic green sheet S is transported to the outlet 50b side while being dried, and the ceramic green sheet S reaching the end of the belt 13 drops vertically downward and rides on the belt 13 of the lower conveying means 3. . When the transfer means 3 of the middle stage is changed to the transfer means 3 of the lower stage, the upper and lower surfaces of the ceramic green sheet S are reversed again.

Again, the ceramic green sheet S whose upper and lower surfaces are turned upside down is carried in from the entrance 49c of the drying chamber 42c by the lower carrying means 3 and is transferred in the through hole 44c in the X direction. When passing through the external heating zone of the through hole 44c, the ceramic green sheet S is mainly dried from the upper surface A surface by the external heating and the hot air supply heating. Evaporated matter from the ceramic green sheet S generated at that time is caused to flow in the W direction in the drying chamber 42c along with the flow W of the warm air supplied from the warm air supply heating device, and the inlet 49c is formed.
Emitted from.

As described above, the ceramic green sheet S is more uniformly and quickly dried while turning the inside of the drying chamber upside down.

Here, an example of a comparative experiment in which the ceramic green sheet is dried using the conventional ceramic green sheet drying apparatus and the ceramic green sheet drying apparatus according to the present invention will be given.

When the ceramic green sheet having a water content of 16.7 wt% before drying is heated by microwave heating at 0.2 kw and dried, the water content is dried to 13.0 wt% at 110 ° C.
Water content is 11.0wt% when heated and heated.
While it was dried to 0.2 kw microwave heating and 1
When it was dried in combination with heating with hot air supply at 10 ° C., the water content was dried to 5.35 wt%. Therefore, in the drying method using the ceramic green sheet drying apparatus according to the present invention, the water content of the ceramic green sheet is reduced to less than 1/2, and the drying time is reduced to less than 1/2, as compared with the drying method by independent heating. We were able to.

As described above, in the ceramic green sheet drying apparatus according to the present invention, since the drying chamber is composed of a plurality of upper and lower stages, the installation area is narrowed and the productivity per used area is increased.

It should be noted that the hot air supply heating zone (not shown) or / and the external heating zone in the lower stage of the ceramic green sheet drying device 21, 41 according to the present invention, the through hole 22b,
A cooling zone for blowing cold air is provided between the outlets 42b and 42c of the ceramic green sheet drying device 2.
It is possible to take out after cooling the ceramic green sheets S from 1, 41.

The microwave heating device 21 in the first embodiment may be replaced by a microwave heating zone provided by external heating, instead of the microwave heating zone, and the drying device may be used together with hot air supply heating. Further, in the ceramic green sheet drying device 41 of the second embodiment, the drying method is limited to the method of passing the ceramic green sheet S through all the drying chambers 42a to 42c and drying it by microwave heating, external heating, hot air supply heating. However, the drying method may be one in which selective heating, for example, microwave heating and warm air supply heating, or external heating and warm air supply heating is selected.

Further, the upper and lower surface reversing device of the ceramic green sheet S is not limited to the above-mentioned embodiment, and is 18 in the longitudinal direction of the ceramic green sheet S during the transfer.
The upper and lower surfaces may be inverted by twisting 0 degree.

The conveying means 3 is not limited to a belt conveyor, but may be a means for rotating a large number of rotating rollers in the through hole of the drying chamber to convey the ceramic green sheet S.

In the ceramic green sheet drying devices 21 and 41 of the first and second embodiments, the hot air supplied from the hot air supply heating device is discharged through the inlets 29a, 29b and 4.
9a-49c, but preferably inlet 2
Exhaust ducts are preferably provided near 9a, 29b, 49a to 49c.

Further, in the ceramic green sheet dryers 21 and 41 of the first and second embodiments, a warm air circulation heating device may be used instead of the warm air supply heating device.

[0056]

As described above, the following effects can be obtained by the ceramic green sheet drying apparatus and the ceramic green sheet drying method according to the present invention.

1. Compared with the conventional ceramic green sheet drying method by single heating such as microwave heating, external heating, and hot air supply heating, by heating them together, they can be dried more quickly and the drying time can be shortened.

2. Since the inside and outside of the ceramic green sheet, or both surfaces of the ceramic green sheet can be uniformly dried, the corrugated phenomenon due to uneven drying is reduced in the dried ceramic green sheet.

3. The inner and outer surfaces and both surfaces of the ceramic green sheet are uniformly dried, so that internal stress during drying is less likely to occur in the dried ceramic green sheet. The amount of warpage of the ceramic sintered body used is reduced.

4. Hot air is blown to each heating zone, and the vapor generated from the ceramic green sheet is discharged from the drying chamber to the outside. Therefore, the steam pressure in the drying chamber rises, and the surface of the ceramic green sheet and the inside of the drying chamber are also increased. Condensation can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a ceramic green sheet drying apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an outline of a ceramic green sheet drying apparatus according to a second embodiment of the present invention.

FIG. 3 is a perspective view showing an outline of a conventional ceramic green sheet drying device.

[Explanation of symbols]

3 Conveying means 21,41 Ceramic green sheet drying device 22,42 Drying chamber 26,46 Microwave heating zone 48 External heating zone S Ceramic green sheet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Inazumi, 2-10-10 Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Inventor Shigeo Kiso 2-26-10 Tenjin, Nagaokakyo, Kyoto Stock Company Murata Manufacturing (72) Inventor Shinya Hashimoto 2-10-10 Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd.

Claims (10)

[Claims] 1. A drying chamber for drying a ceramic green sheet, and a transport means for transporting the ceramic green sheet in the drying chamber, wherein the drying chamber is a micro-chamber for the ceramic green sheet transported by the transport means. A ceramic green sheet drying device, which has a microwave heating zone for wave heating, and is provided with a warm air supply heating device in this microwave heating zone. 2. A drying chamber for drying the ceramic green sheet, and a transporting means for transporting the ceramic green sheet in the drying chamber, wherein the drying chamber transports the ceramic green sheet by the transporting means. Having a microwave heating zone for microwave heating and an external heating zone for heating from outside,
A heating device for supplying hot air to the microwave heating zone and the external heating zone. 3. The ceramic green sheet drying device according to claim 1, wherein the conveying means includes means for reversing the upper and lower surfaces of the ceramic green sheet. 4. The conveying means is composed of at least two stages above and below, and the conveying directions of the upper and lower two stages are opposite to each other, and the ceramic green sheet is unidirectional by the upper conveying means. Is transferred to the lower transfer means from the transfer means at the final end of the upper transfer means, and is transferred in the reverse direction by the lower transfer means,
The ceramic green sheet drying device according to claim 1 or 2, wherein the upper and lower surfaces of the ceramic green sheet are reversed. 5. A drying chamber for drying the ceramic green sheet, and a transport means for transporting the ceramic green sheet in the drying chamber, wherein the drying chamber transports the ceramic green sheet by the transport means. Having a microwave heating zone for microwave heating and an external heating zone for heating from outside,
A heating device for supplying hot air is provided in the microwave heating zone and the external heating zone, and the conveying means is composed of at least two stages above and below. 6. The ceramic green sheet drying apparatus according to claim 1, wherein the drying chamber has a cooling zone near an outlet of the drying chamber. 7. A method for drying a ceramic green sheet, which comprises heating a ceramic green sheet transferred by a transfer means for transferring a ceramic green sheet by microwave heating and heating by supplying hot air. 8. A ceramic green sheet transferred by a transfer means for transferring a ceramic green sheet is microwave-heated and hot-air supplied and heated to dry, and then externally heated and hot-air supplied and heated. A method for drying a ceramic green sheet, which comprises: 9. The method of drying a ceramic green sheet according to claim 7, wherein the ceramic green sheet is dried by inverting the upper and lower surfaces thereof during transportation for drying. 10. When the ceramic green sheet is conveyed to the lower conveying means by heating the ceramic green sheet on the upper conveying means using at least two upper and lower conveying means, 8. The upper and lower surfaces are turned upside down, and the ceramic green sheet is heated on the lower conveying means.
Or the method for drying a ceramic green sheet according to item 8.