JPH0729846B2 - Microwave heating device for clay compacts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides an extruded product obtained by continuously extruding a raw material containing clay as a main component in a predetermined shape in a short time of about 10 minutes to 1 hour. The present invention relates to a microwave heating device for a clay molded body, which can be reduced to 1/3 to 1/2 and can absorb the volume shrinkage of the extruded molded body during drying and send it to the next step.

[Conventional technology]

In general, an inner wall material and roof tile made of clay are extruded in a predetermined shape, and are immediately cut into a short length, for example, a length of 10 to 30 cm, and the waste heat of a firing furnace is used for about 1 to 1 cm. A device that reduces the water content to 1 to 0% in about 3 days was common.

[Problems to be solved by the invention]

Not only does a conventional clay molding drying apparatus take several days to dry, but especially clay moldings longer than before cannot be transported without using an underlay plate, resulting in poor productivity and cost increase. It invited me and required a vast site. Furthermore, when the drying time is shortened by 1 day with a drying device that heats and dries from the conventional surface, the surface layer dries first, and the roof tiles, tiles, and outer wall materials are twisted or warped by the steam pressure inside. However, there are drawbacks such as cracking, cracking, and destruction, and it has been extremely difficult to shorten the drying time. Also, instead of drying by heating from the surface, it is conceivable to use an internal heating device, such as a microwave heater or a far infrared heater, but in the case of simply using each device, in the former case, the material to be dried can be heated to 130 ° C. It was difficult to do so, the rapid heating resulted in explosion, and the equipment and energy cost were higher than the latter. Further, in the latter, the time required to reach the inside of the material to be dried is longer than in the former, but each drying device has advantages and disadvantages because it is much more advantageous than the former to raise the internal temperature. In addition, in the above two devices, there are various problems in the dew condensation prevention treatment of a large amount of water vapor generated during drying, and various problems in the transport structure during drying of the material to be dried, such as deformation and lengthening due to frictional resistance between the material to be dried and the conveyor belt. Cracks were generated due to non-uniform heating of microwaves on the scale.

[Means for solving problems]

In order to eliminate such drawbacks, the present invention supplies air or the like to the transfer section of the microwave heating machine and the space to be heated, and disposes a special transfer machine at the inlet of the microwave heating apparatus to form clay. Provided is a microwave heating device for a clay molded body, which can be dried rapidly (about 5 to 60 minutes) without cracking, deformation or explosion when the body is dried.

〔Example〕

Hereinafter, an embodiment of a microwave heating device for a clay molded body according to the present invention will be described in detail with reference to the drawings. 1 (a), (b), and FIG. 2 are explanatory views showing a typical example of the above apparatus. That is, the microwave heating device converts the microwave α into heat energy without the time required for heat conduction by penetration of the microwave α into the inside of the extruded product A (shown in FIGS. 5 (a) to (j)). It is for converting and generating heat in seconds to minutes to evaporate the water in the clay. In addition, the water content in the extrusion-molded product A is 22 to 15 by weight.
%, Of which 5 to 10%, for example, can be evaporated. In particular, the volume of the seed extruded product A shrinks until the water content becomes about 5 to 8%, but when the water content is less than that, the volume shrinkage does not occur. Therefore, specifically describing the microwave heating device, a waveguide 1 for guiding the microwave α oscillated from a microwave oscillator (not shown) to a required location, and a reflection plate 2 for reflecting the guided microwave α. A rotary vane 3 for agitating the reflected microwaves α, a conveying section 4 composed of a fli roller configured to move the extruded body A at an extruding speed but not cause a spark, and an inlet / outlet 5 of the extruded body A , 6 and air and the like β from the heated space 7 in large quantities to be sucked in or supplied to the heated space 7, and an enclosure 9 surrounded by the microwave α so as not to leak to the outside. It is composed. The inlets and outlets 5 and 6 are formed to have a structure and length that also function as a filter that prevents the microwave α from leaking to the outside. Further, although the heated space 7 for heating the extruded body A differs depending on the purpose,
For example, it is about 1 to 5 m. Furthermore, the transport unit 4
Indicates that the microwaves α, β such as air are uniformly radiated or blown to the extruded product A, and that the entire extruded product A contracts about 10% when it is dried. The configuration is such that A can be transported. As shown in FIGS. 3 (a) and 3 (b), an example thereof is a pipe-shaped flea roller composed of a fixed core rod 4a and Teflon.
4b and a core rod support 10 as shown in FIG. 4, and a shield plate 11 provided as necessary. Further explaining, in FIG. 3 (a), the width of the free roller 4b is divided into three, and the resistance when passing through the extrusion molded body A is made smaller,
(B) The figure shows a flea roller 4b constituted by one line. Also,
The core rod support 10 is provided with a through hole 10a so that the microwave α is irradiated from the back surface of the extruded product A as well.
In addition, when the extruded body A is a long body, the shielding plate 11 suppresses that the irradiation of the microwave α is physically high at both upper ends and both ends in the longitudinal direction, and uniformly heats the shielding plate 11. It is useful for. Further, the air supply port 8 is air such as a compressor and a ring blower (including dry air, warm air, and air).
Is connected to an air-cycle prime mover 12 capable of blowing or sucking air. Reference numeral 13 denotes a transfer unit in which a free roller 14 and a drive belt 15 are arranged in front of the inlet 5 on the same path line as the inlet 5, and the extruder B (shown by a chain double-dashed line in FIG. 1A). It is for feeding the extruded product A extruded from the microwave heating device to the microwave heating device without deformation at the same extrusion speed.

Next, the operation will be described.

First, a clay consisting of Shigaraki clay, chamotte and a water reducing agent is prepared as a raw material. The weight% is, for example, Shigaraki clay 61.5%, chamotte 18%, water reducing agent 0.5% (trade name: Cell Flow, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), water 20% in a kneading machine (MP-
100 type manufactured by Miyazaki Iron Works Co., Ltd.). Also, as the extrusion molding machine B, a model name M with an extrusion capacity of 100 to 150 / hr is used.
V-FM-A1 type (manufactured by Miyazaki Tekko Co., Ltd.) was used. The microwave heating device has a frequency of 2450 MHz, an output of 5 kw, and the length of the heated space 7 is 3 m. A large amount of β such as air is sent to the heated space 7 from the air supply port 8 of the enclosure 9, The steam β ′ generated during heating is discharged to the outside from the outlets 5 and 6, the steam pressure in the heated space 7 is reduced, and condensed water can be prevented from being generated on the object to be heated and the inner wall of the enclosure 9. The transport unit 4 is a free roller made of a Teflon pipe. In addition, the microwave heating is applied to the moisture of the extruded product A 18
% (% By weight) was evaporated to 7% (% by weight), and the remaining water content was set to be evaporated by another heating device such as a far infrared heater device (not shown). Furthermore, the extrusion speed of the extruder is 300-1000mm / min, here 400mm / min.
And In addition, the pass lines of the extruded product A (here, a continuous formed product) have the same height, and the extruded product A
Is fed to the transfer device 13 and the microwave heating device as it is at the extrusion speed of the extrusion molding machine B, and the volume is contracted due to the evaporation of water on the free rollers 4b of the transfer section 4 in the microwave heating device. It is designed to absorb the difference.
Therefore, the clay supplied to the extruder B is delivered from its outlet in a continuous body having a cross section shown in Fig. 5 (a). The extruded product A sent out is fed to the microwave heating device via the transfer device 13, and the water content of the extruded product A is up to 7% (weight ratio) while passing through the heated space 7 of the microwave heating device. It is reduced in 5 minutes and is sent to the next process from the outlet 6. The steam β ′ in the heated space 7 enters and exits the outlets 5, 6
The following effects can be obtained by discharging from the arrow to the arrow. That is, the release of air or the like β from the heated space 7 prevents the steam pressure of the heated space 7 from increasing and prevents the extruded body A from overheating and breaking due to abrupt heating, and the air or the like β In combination with cooling the exposed surface of the extruded product A by applying a flow to the air layer near the front and back surfaces of the extruded product A during heating, while suppressing overheat and shortening the drying time, Condensation is prevented from occurring on the exposed surface of the extruded product A and the inner wall of the heated space 7. The semi-dried extruded product A is fed to the next step.

What has been described above is only one example of the microwave heating device for a clay molded body according to the present invention, and instead of the air cycle prime mover 12 as shown by the one-dot chain line in FIG. In combination with this, air and warm air may be supplied to the heated space 7 from the bottom surface of the enclosure 9 and discharged from the inlets and outlets 5 and 6.

〔The invention's effect〕

As described above, according to the microwave heating device for a clay molded body according to the present invention, the clay extruded molded body (short length) containing 22 to 15% (weight ratio) of water is not deformed. Moreover, it is characterized by being able to reduce the water content to 1/3 to 1/2 by shortening it to 1/10 to 1/100 of the previous one without cracks and explosions. Further, the volume of the extruded product shrinks by 10% or more as compared with that at the time of extruding, but there is a characteristic that it can be absorbed and transferred to the next step without any adverse effect of the conveying speed on the extruded product. Furthermore, since the water vapor in the heated space is released to the outside,
It is characterized by preventing adverse effects on the inner wall of the heated space and the surface of the object to be heated, the occurrence of dew condensation, and the reduction of the evaporation speed. Further, the microwave is irradiated to the object to be heated from below, concentrated on the weakly heated portion, and the like, so that the drying can be made uniform and adverse effects at the time of drying can be prevented.

[Brief description of drawings]

1 (a) and 1 (b) are schematic configuration diagrams showing an embodiment of a microwave heating apparatus for a clay molded body according to the present invention and a sectional view taken along the line Ey, FIG. 2, FIG. 3 (a), (B), FIG. 4 is an explanatory view showing an embodiment of the transport section, and FIGS. 5 (a) to (j).
FIG. 3 is an explanatory view showing a cross section of an extruded body. 4 ... conveying section, 7 ... heated space, 8 ... air supply port,
13 …… Transfer machine, α …… Microwave, β …… Air, etc.

Claims (1)

[Claims] 1. A microwave heating device of continuous oven type, wherein a conveying portion in a heated space is a flea roller, and
At least one air supply port for supplying air or the like to the heated space is provided, and the supplied air or the like is discharged only from the inlet or outlet of the heated space, and the frill roller is provided in front of the inlet. A microwave heating device for a clay molded body, characterized in that a transfer device including a driving belt and a driving belt is installed.