JPH0729845B2 - Rapid drying equipment for hollow clay compacts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a clay molded body obtained by continuously extruding a raw material containing clay as a main component in a predetermined shape having a hollow portion in a short time of about 10 minutes to 1 hour. The present invention relates to a rapid drying apparatus for hollow clay moldings which can be dried without warping, twisting, cracking, or explosion by the combined use of microwaves, far-infrared rays, air, or the like due to its synergistic effect.

[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. The water content was reduced to 1 to 0% in about 3 days and then supplied to the firing furnace.

[Problems to be solved by the invention]

However, the conventional drying method has a drawback that it is difficult to dry a long hollow body and a long thin hollow body, and even a short body requires several days to dry. That is,
Conventionally, it is long and hollow for the process of cutting it to a standard length (10 to 30 cm) immediately after leaving the extruder, placing it on a trolley and feeding it to the dryer for several days. The soft extrudate immediately after extrusion cannot be dried while maintaining its original shape for a long time, and there is a drawback that the long hollow body cannot be dried due to molding. Further, in the past, the technical idea of the continuous line did not exist due to the above-described number of days after the extruder and after drying, resulting in poor productivity and high cost. Also,
If you want to greatly reduce the drying time by simply drying the hollow long molded body with microwaves, etc., increase the water vapor pressure of the hollow part and the occurrence of dew condensation, and the dryness of the inner wall and outer surface of the hollow part If there is not a considerable thickness due to the displacement, there is a defect that explosion, cracking, warpage, deformation such as twisting occurs. In addition, the microwave needs to raise the temperature to 130 ° C. or more in order to reduce the water content of the extruded product to 1% or less, but there was a considerable time and energy loss to raise the temperature to this temperature. There is also a method of drying by using far infrared rays instead of microwaves, but heating the extruded body to 130 ° C or higher takes a much shorter time than microwaves, but there is a weakness that the drying time becomes long. there were. Moreover, above 2
In the drying device using the device, a large amount of water vapor generated during drying is prevented from dew condensation, and there are various problems in the transport structure during drying of the material to be dried, such as deformation due to friction resistance between the material to be dried and the conveyor belt, long There was non-uniform heating of microwaves on the scale.

[Means for solving problems]

The present invention, in order to eliminate such defects, a transfer machine that smoothly transfers the hollow extrusion molded article to the next step after the extrusion molding machine, and then 1/3 of the water content of the continuous strip-shaped hollow extrusion molded article. Microwave heater that evaporates in a short time (about 5 to 30 minutes),
Next, the far-infrared heater device that reduces the water content of this hollow extruded body to 1% or less in a short time of, for example, 5 to 30 minutes is arranged in that order, and the steam that accumulates inside the hollow portion during heating is extruded. The air blown from the air outlet provided in the core of the machine (air, dry air) blows it off to reduce the water vapor pressure and increase the heating efficiency in the hollow part, while eliminating the dew condensation in the hollow part And the water content of the surface layer of the hollow extruded body is averaged, and the water vapor in the microwave heating space and the water vapor on the surface of the hollow extruded body are blown to the outside to prevent dew condensation on the surface and on the inner wall of the heated space. Prevents the inner and outer wall surfaces of the hollow extruded body from being blown away with air at all times, reducing the drying efficiency and drying time to 1/10 to 300 of the previous level, and cracking and warping the dried object. ,
It is intended to provide a rapid drying apparatus for hollow clay molded bodies, which can continuously dry long hollow bodies without causing deformation such as twisting and explosion and by a device that is much more compact than before.

〔Example〕

An embodiment of a rapid drying apparatus for hollow clay molded bodies according to the present invention will be described in detail below with reference to the drawings. 1 (a) and 1 (b) are explanatory views showing a typical example of the above apparatus. In the figure, reference numeral 1 is an extruder, and a raw material containing clay as a main material is introduced through a die 2 and a core 3 as shown in FIGS. 2 (a) and 2 (b), for example, FIGS. The extrusion molding body A having a hollow cross-section shown in) is continuously extruded. For example, the extrusion speed is about 200 to 2000 mm / min although it depends on the thickness and width of the extrusion molding body A. More specifically, the core 3 is formed of a large number of outlet portions 4 and a connecting pipe 6 for supplying air to the common portion 5 from the outside or discharging air and water vapor from the inside.
Is formed into a hollow body having the same cross section as the hollow portion a of the extruded body A, and is formed integrally with the common portion 5 so as to correspond to the arrangement of the hollow portions a of the extruded body A. is there. In addition, the core 3 is formed from the tip 3a to the end 3b, for example, so that the clay extruded from the extrusion port 1'of the extrusion molding machine 1 can be extruded from the die 2 without interruption by a continuous body having a hollow portion a of a predetermined shape. It is formed in a streamlined shape. Further, the hollow portion 3c of the core 3 is supplied with a required amount of at least one kind of air, dry air, wet air, warm air, etc. from a pump 7 installed outside through a hose 8, or the hollow portion a
The water vapor is discharged to promote the drying of the hollow portion a of the extrusion molded body A, which is difficult to dry, and at the same time, it functions to eliminate the adverse effects such as deformation at that time. In addition, the above-mentioned clay is a natural product and has different components depending on each production site, and these advantages and disadvantages are mutually offset to obtain a predetermined mixed clay. As a specific example thereof, porcelain stone, feldspar, kaolinite, halosite, metahalosite, kibushi clay, frog eye clay, Shigaraki clay, chamotte, etc. are crushed and added with water and kneaded. If necessary, this clay may be ironed by a magnet. Reference numeral 9 denotes a transfer device, which is, for example, a flea roller 10, or at least one kind of a drive belt 11 synchronized with an extrusion speed, or a combination thereof as shown in the drawing.
It is for feeding the extrusion-molded body A to the next step without deformation at the extrusion speed. Reference numeral 12 is a microwave heater having an oven continuous structure, which mainly permeates into the inside of the extruded product A and converts the microwave B into heat energy without taking time to transfer the heat, and from several seconds to several seconds. It is for generating heat in minutes to evaporate the water in the clay. In addition,
Moisture is contained in the extruded product A in an amount of about 22 to 15% by weight, of which 5 to 10%, for example, can be evaporated. In particular, the volume of this type of 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,
The microwave heater 12 will be described in detail. A waveguide 13 that guides the microwave B oscillated from a microwave oscillator (not shown) to a required location, and a reflection plate 14 that reflects the guided microwave B. A rotary blade 15 for stirring the reflected microwaves, a conveying unit 16 composed of a fli roller configured to move the extruded body A at an extruding speed at the extrusion speed but not spark, and the inlets and outlets 17 and 18 of the extruded body A. And an air inlet / outlet 20 for sucking a large amount of air C or the like from the heated space 19 and supplying the heated space 19 to the heated space 19 and an enclosure 21 enclosing the microwave B so as not to leak outside. Is. The inlets and outlets 17 and 18 are formed to have a structure and length that also function as a filter so that the microwave B does not leak to the outside. The heated space 19 for heating the extruded body A differs depending on the purpose, but is, for example, about 1 to 5 m.
It is a place. Further, the conveying unit 16 uniformly irradiates or blows the microwave B, air or the like C onto the extruded product A from the front surface, the back surface, and the side surface, and when the extruded product A dries, about 10% of the whole. Contracts, so that the extruded product A can be conveyed while absorbing this. As an example, as shown in FIGS. 4 (a) and 4 (b), a fixed core rod 22 and a pipe-shaped flee roller 23 made of Teflon and a core rod support 24 as shown in FIG.
And a shielding plate 25 provided as needed. To further explain, referring to FIG.
23 is a structure in which the width is divided into three, and the resistance when passing through the extruded product A is further reduced.
3 '. Further, the core rod support 24 is provided with a through hole 24a so that the microwave B is also irradiated from the back surface of the extrusion molded body A. In addition, when the extruded body A is a long body, the shielding plate 25 suppresses the irradiation of the microwave B at a high density on both upper ends of the extruded body A and in the longitudinal direction, and uniformly heats the shielding plate 25. It is useful for. Further, the air inlet / outlet 20 is connected to an air cycle pump 7 capable of blowing air (including dry air, warm air, and air) such as a compressor and a ring blower, or sucking air. 26 is a far-infrared heater device for raising the temperature of the extruded product A to 130 ° C. or more in order to reduce the water content of the extruded product A to 1 to 0%, and its constitution is at least one of a flea roller and a drive belt. And a far-infrared heater 28 and a heat insulation box 29, and the heating zone is about 2 to 10 m. Of course, the heating zone differs depending on the thickness, width, and conveyance speed of the extruded product A that has become a semi-dried product. A traveling cutter 30 cuts the dry extruded body A'to a predetermined length.

Next, the operation will be described.

First, a clay consisting of Shigaraki clay, chamotte, a water reducing agent and water 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% clay mixer (MP
-100 type manufactured by Miyazaki Tekko Co., Ltd.). Also,
As the extrusion molding machine 1, a model name MV-FM-A-1 type (manufactured by Miyazaki Tekko Co., Ltd.) having an extrusion capacity of 100 to 150 / hr was used. The pump 7 uses a ring blower to connect dry air heated by compression when blown to 20 to 50 ° C. to the connecting pipe 6 exposed to the outside of the base 2 via the hose 8 and another hose 8 (one-dot chain line). (Indicated by) is connected to the air inlet / outlet port 20 of the microwave heater 12 . Further, the far-infrared heater device 26 has ten far-infrared heaters 28 arranged every 10 meters so that the moisture in the extruded product A can be diffused to the surface to accelerate dehydration and reduce the moisture to 1% or less. Is. Further, the extrusion speed of the extrusion molding machine 1 is 200 mm / min and the extrusion is performed in the cross section shown in FIG. 3 (a).
Was cut into a dry extruded product A ′, and the line distance from the die 2 to the traveling cutter 30 was set to 15 m. Of course, the length of this line is set according to the shape, width, and thickness of the extruded product A. The pass lines of the extrusion molded body A were at the same height, and the moving speed of the transfer machine 9 was set so as to be synchronized with the extrusion speed. Therefore, the raw material containing clay as the main material is continuously extruded from the extruder 1 onto the transfer machine 9 in the cross section shown in FIG. The extruded product A that has been extruded is fed to the microwave heating machine 12 at the above-mentioned speed, and while passing through the heated space 19 of the microwave heating device 12 , the hollow part of the extruded product A is generated by the microwave B and the air C. a and a large amount of water vapor generated by microwave heating by air C sent to the outer surface at the same time both inside and outside the hollow portion a to make it easy to evaporate at all times, thereby eliminating the occurrence of dew condensation and soft extruding. The rigidity of the molded body A is increased to an average in a short time so as to prevent cracking, warpage, deformation, and explosion due to overheating, and the 1 / 3rd position of the water content of the extruded molding A is reduced to about 5 to 10 minutes. Evaporate and feed it to the far infrared heater device 26 to dry it to less than 1% of water content, feed it to the traveling cutter 30, and cut the dried continuous strip dry extruded product A into a predetermined length. did. Then, the extrusion-molded body A was dried in a short time of about 15 to 30 minutes from extrusion to cutting and as a continuous body. When the extruded product A was simply heated using microwaves, it was rapidly heated from the inside for a short period of time, and the adverse effects of explosion and dew condensation were severe and it was not practical.

What has been described above is only one example of the rapid drying apparatus for a hollow clay molded body according to the present invention. In FIG. 1 (a), the microwave heating machine 12 is used in combination with the pump 7 as shown by the chain double-dashed line. Alternatively, an air supply device may be independently provided instead of the pump 7, or a far-infrared heater device may be provided as indicated by a chain line.
It is also possible to supply hot air or hot air to the 26 to further shorten the drying time. Of course, although not shown, it is possible to supply one or more kinds of hot air, hot air, etc. to the microwave heater 12 .

〔The invention's effect〕

As described above, according to the apparatus for rapidly drying a hollow clay molded body according to the present invention, a hollow extruded molded body containing water in an amount of 22 to 15% (weight ratio) is heated in two stages and extruded into the hollow portion. It is characterized in that air or the like is sent to eliminate the adverse effect of water vapor during drying from the inner and outer surfaces of the extruded product, and the extruded product can be dried without cracking, twisting, warping or explosion in a continuous state in a short time.
In addition, productivity is 10% compared to the speed that took several days before.
It has the characteristic that it takes about 60 minutes to dry. Furthermore, the volume of the extruded product shrinks by 10% or more when dried, compared to when extruded.
There is an advantage that the adverse effect on the extruded product due to it can be absorbed and manufactured by a flea roller or the like. Further, in the present invention, since the process from extrusion to drying is arranged in series, there is a feature that a long body and a continuous body can be dried quickly. In addition, since the water vapor in the heated space is released to the outside, it has a characteristic that the adverse effect 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 are prevented. Another characteristic is that the drying is made uniform by concentrating microwaves on the back surface, front surface, and weakly heated portion of the extruded body.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) and FIG. 1 (b) are schematic configuration diagrams showing an embodiment of a rapid drying apparatus for hollow clay molded articles according to the present invention, a sectional view taken along the line EE, and FIG. (A) is explanatory drawing which shows the exit part of an extrusion molding machine, (b) is an explanatory drawing which extracts and shows a core, FIG.3 (a)-(n) is sectional drawing which shows an example of an extrusion molded body. , 4th
FIGS. (A), (b), and FIG. 5 are explanatory views showing the main constituent members of the transfer section of the microwave heater. 1 ... Extruder, 3 ... Core, 7 ... Pump, 9 ...
Transfer machine, 12 ...... Microwave heating machine, 26 ...... Far infrared heater device.

Claims (1)

[Claims] 1. An extruder having a core for continuously extruding a raw material containing clay as a main material in a predetermined shape having a hollow portion, and an extrusion molded body continuously extruded from the extruder smoothly A transfer machine for transferring to the process, an oven continuous microwave heater for reducing the water content of the extruded product delivered from the extruding machine in a short time, and the water content of the extruded product that has passed through the microwave heating device. A far infrared heater device for reducing and increasing the temperature is arranged in series, and a pump for feeding gas from the outside to the core installed in the mouthpiece of the extrusion molding machine without hindering the extrusion molding body. An apparatus for rapid drying of a hollow clay molded body is provided with an air inlet / outlet for supplying air to a wall in the heated space other than the inlet / outlet of the microwave heater.