JPH0469845B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a slurry casting device used for molding inorganic molded products such as ceramic molded products and concrete molded products.

[Conventional technology]

There are generally two methods for producing inorganic products such as ceramic products and concrete products: wet methods and dry methods. In the dry method, a dry powder composition is created by appropriately combining clay raw materials, felsic stone, and powder raw materials such as talc, dolomite, and lime, and this is poured into the molding recesses of a pair of upper and lower molds. In this method, the molded product is closed, the charged composition is pressure-molded, the molded product is removed from the lower mold, and then fired. This method requires a large amount of pressure to press-form the dry powder composition into a molded article. Therefore, especially when making large molded products, extremely large equipment is required, and
When pressurizing and compacting a dry powder composition, the distribution of the powder becomes uneven, causing distortion, etc., which leads to cracks and cracks in the molded product, which has the disadvantage of increasing the number of defective products. .

[Problem to be solved by the invention]

For this reason, wet methods have recently been used. In the wet method, a wet composition (raw material slurry) with a predetermined moisture content is created by appropriately combining the same raw materials used in the dry method described above, this composition is placed in a plaster mold, and the moisture is removed using pressure such as a hydraulic press. The wet composition is passed through the mold to drain water, forming a molded product made of the solid component of the wet composition in the mold. and,
In this method, the molded product is removed from the mold, dried, and then fired in a kiln to produce an inorganic product. For example, regarding molding a wet composition in a mold,
Publication No. 18210 uses a mold whose outer part is made of a synthetic resin material and whose inner part is made of plaster, supplies a single batch of slurry into the molding space, pressurizes the inside of the molding space with compressed air, and at the same time, A technique has been disclosed in which vacuum suction is applied from the outer periphery of a molding space to deposit slurry on the wall surface of the molding space, thereby molding a hollow thin-walled molded product. This technique requires a separate weighing device because it is necessary to weigh one batch of raw material slurry to be supplied into the molding space, and has drawbacks such as measurement errors and the like. Also, 30cm
Another drawback is that it is not possible to manufacture solid, high-density molded products such as large square tiles.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a slurry casting apparatus that can efficiently manufacture solid high-density molded products such as large tiles.

[Means to solve the problem]

In order to achieve the above object, the slurry casting device of the present invention includes an upper mold and a lower mold having water permeability, and a suction mold having one end extending into the molds and the other end communicating with a suction/compression means. - A compression pipe, a slurry extruder whose discharge part communicates with the molding space created by both of the molds, its drive motor, and a pressure sensor that detects the pressure in the molding space and outputs a pressure signal. , is electrically connected to the pressure sensor and the drive motor, and compares the output signal value A of the pressure sensor with the pre-input set pressure value B, and calculates the drive signal by the following equation (1).
The configuration includes a controller that outputs a drive stop signal to the drive motor in the case of (2).

A<B...(1) A≧B...(2) [Operation] Slurry is supplied from a slurry extruder into the molding space created by the upper mold and the lower mold. The pressure sensor detects the pressure within the molding space and outputs a pressure signal to the controller. The controller outputs a drive stop signal to the drive motor of the slurry extruder when the pressure signal exceeds a set pressure value input in advance. Water is removed from the slurry supplied into the molding space by the suction action of the suction and compression pipe. When the pressure in the molding space decreases due to the removal of water, the pressure sensor detects this and based on the signal, the controller sends a drive signal to the drive motor of the slurry extruder. This drives the slurry extruder and supplies slurry to the molding space again. By repeating these operations, the slurry is repeatedly supplied into the molding space, thereby forming a solid and dense molded product such as a large 30 cm square tile.

Next, this invention will be explained in detail.

FIG. 1 shows a slurry casting apparatus of the present invention. In the figure, 1 is a square plate-shaped upper base plate of the upper mold, and a square plate-shaped base plate 2 of a hydraulic cylinder 19.
0 and four arms 21 and 22, and is configured to move up and down by the drive of a hydraulic cylinder 19. This upper base plate 1 is provided with an upper formwork 2 having a U-shaped cross section facing downward, and a porous elastic body 3 made of resin with continuous pores is disposed within the U-shaped upper formwork 2. has been done. A molding recess 3 a is formed on the surface of the porous elastic body 3 . Furthermore, a suction/compression pipe 4 having a large number of openings on the outer circumferential surface is inserted inside the porous elastic body 3, and the ends of the suction/compression pipe 4 are connected to a vacuum suction pipe 5 and a compressed air pipe 6. It is connected to a pump (not shown) and a compressed air pump (not shown). Reference numerals 7 and 8 indicate switching valves for switching between the vacuum suction and compressed air. Reference numeral 11 denotes a lower base plate of the lower mold corresponding to the upper base plate 1, which is supported and fixed by support columns 9 and 10. Reference numeral 12 denotes a lower formwork having a U-shaped cross section and provided on the lower base board 11, and a porous elastic body 13 made of resin and having continuous pores is disposed inside thereof. The surface of this porous elastic body 13 is also formed with a molding recess 13a, similar to the porous elastic body 3 of the upper mold 2, and a suction/compression pipe 14 is inserted inside. and,
A vacuum suction pipe 15 and a compressed air pipe 16 are connected to the ends of this suction/compression pipe 14, and are operated by a vacuum pump (not shown) and a compressed air pump (not shown), respectively. It's summery. Reference numerals 17 and 18 are switching valves for switching between the vacuum suction and compressed air. 23
is a screw type extruder, and the tip of this extruder 23 is communicated with the molding recess 13a of the lower mold frame 12 through a pipe 24. 29 is a supply port for supplying the raw material slurry 30 to the screw extruder 23; 25 is the screw extruder 23;
This is the motor that drives the screw. and,
A pressure sensor 26 is provided on the pipe 24 of the screw type extruder 23, and this pressure sensor 2
A connection line 26a extends from the signal amplifier 27 to the signal amplifier 27, and a signal line 27a extends from the signal amplifier 27 to the controller 28.
is extending. A control signal line 28a extends from the controller 28 to the motor 25. The pressure sensor 26 detects the pressure within the molding space formed by the molding recesses 3a and 13a of the porous elastic body 3 with continuous pores of the upper mold and the porous elastic body 13 with continuous pores of the lower mold. The detection signal is sent to the signal amplifier 27. The signal amplifier 27 amplifies this signal and sends it to the controller 28, which compares the set value inputted in advance with the input signal value,
When the input signal value is lower than the set value, a drive signal is sent to the motor 25 via the control signal line 28a. When the input signal value is the same as or close to the set value, a drive stop signal for the motor 25 is sent. In this way, the pressure within the molding space is kept constant.

In this configuration, as shown in FIG. 1, with the mold closed, the raw material slurry 30 is press-fitted from the screw extruder 23 into the molding space created by the molding recesses 3a, 13a. Then, vacuum suction is performed by the suction/compression pipes 4 and 14 of the upper mold and the lower mold to suction and dehydrate the water in the raw material slurry 30. As a result, the pressure in the molding space decreases, and this decrease in pressure causes the pressure sensor 26 to
The motor 25 is driven via the signal amplifier 27 and the controller 28, and the raw material slurry 30 is pumped into the molding space from the screw extruder 23 until the pressure in the molding space becomes constant. Supplied. In this way, the operations of suction dehydration of the raw material slurry 30 supplied into the molding space and supply of an amount of raw material slurry corresponding to the suction dehydration are repeated to perform molding. The molded product obtained is dense, free of pores and voids, and is solid and large. Next, when the molded product is formed in this way, the lower mold is suctioned and
Compressed air is discharged from the compression pipe 14 to separate the molded product from the mold surface, and at the same time, the hydraulic cylinder 19 is activated to raise the upper mold as shown in FIG. A receiving tray (not shown) for receiving the molded product is inserted into the space. In this case, the suction/compression pipe 4 of the upper mold maintains the suction state. Therefore, the molded product 31 rises while being sucked into the molding recess 3a of the upper mold. Next, in this state, compressed air is fed into the suction/compression pipe 4 of the upper mold by switching the switching valves 7 and 8. As a result, the molded product 31 falls from the mold surface of the upper mold into the receiving tray. Then, when a plurality of molded products are collected, they are put into a curing device such as an autoclave or a kiln and hardened by firing and curing.

In this way, solid and dense molded products such as large tiles of 30 cm square can be manufactured efficiently. Further, according to the apparatus of the present invention, a low viscosity raw material slurry with a low solid content concentration and a high water content can be used as the raw material slurry. Therefore, a molded product having a complicated shape can be easily formed, and no distortion occurs in the molded product because no excessive pressure is applied during the formation. Therefore, the resulting product does not warp due to the above distortion. Further, since water is removed by suction from both the upper mold and the lower mold, the water can be quickly removed and the molding speed can be improved. Furthermore, during molding, the raw material slurry equivalent to the moisture that has been sucked and dehydrated from the raw material slurry is automatically supplied, eliminating the need for the traditional method of accurately weighing the raw material and putting it into the mold. There is no need to perform any additional work, and the number of man-hours required can be reduced.

〔Effect of the invention〕

The slurry casting device of the present invention includes a slurry extruder whose discharge section communicates with a molding space formed by both upper and lower molds, a drive motor for the slurry extruder, and a pressure sensor that detects the pressure in the molding space and outputs a pressure signal. The sensor is electrically connected to the pressure sensor and the drive motor, and the output signal value A of the pressure sensor is compared with the pre-input setting signal value B, and the drive signal is calculated by the equation (2) when the above equation (1) is satisfied. ) is provided with a controller that outputs a drive stop signal to the drive motor. Therefore, the slurry is extruded and supplied into the molding space from the slurry extruder until the output pressure signal of the pressure sensor reaches a predetermined value, and the slurry is supplied by the suction action of the suction/compression pipe. Vacuum suction is performed to remove moisture from the slurry. Then, a pressure sensor detects the resulting decrease in pressure within the molding space, and the slurry extruder is driven again to supply slurry to the molding space again. By repeating this process, a molded product is formed. In this case, the resulting molded product is solid and has a high density because the extrusion pressure of the slurry by the slurry extruder is repeatedly applied, and in addition to this, the vacuum suction force of the suction/compression pipe is applied. The result is a molded product, etc. In this way, this device uses the extrusion force of the slurry extruder not only to supply slurry but also to apply pressure to the molded product, and in combination with a pressure sensor, repeatedly applies pressure to the molded product. . Therefore,
With the present device, it is possible to manufacture solid, high-density molded products such as tiles of 30 cm square. Furthermore, with this device, the slurry is automatically supplied, so there is no need to measure the raw material slurry.

Next, the present invention will be explained based on examples.

〔Example〕

First, a device as shown in FIG. 1 was prepared as a slurry casting device. Next, clay raw material 40
Parts by weight (hereinafter abbreviated as "parts"), felsic powder raw material
Raw material slurry 30, which is a ceramic raw material composition consisting of 55 parts of talc and 5 parts of talc, and whose water content is set at about 20%, was poured into the molding space from the screw extruder 23 at 20 kg/cm ² . . The composition was then drained using vacuum suction.
In this case, due to the action of the pressure sensor 26, the screw type extruder 23 was operated as the suction dehydration progressed, and the raw material slurry 30 was supplied into the molding space. After molding in this way for 15 minutes, open the mold and take out the molded product onto a tray. After drying this molded product at 300-500℃ for 1-3 hours, it is heated in a firing oven at a temperature of 1000℃ or higher. and baked. In this case, drying and firing were carried out by pre-drying and pre-heating so as not to cause cracks in the molded article, followed by main drying and main heating. The thus obtained ceramic product (tile) had large dimensions of 300 x 300 x 10 mm, and was in a homogeneous state without any voids or voids. Furthermore, there was no warping or cracking, and the strength was extremely high.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a slurry casting apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of its operation. 1... Upper base board, 2, 12... Formwork, 3, 13...
... Porous elastic body, 3a, 13a ... recess for molding,
26...Pressure sensor, 27...Signal amplifier, 2
8...control machine.

Claims (1)

[Scope of Claims] 1. Upper and lower molds having water permeability, one end of which extends into the two molds, and the other end of which is capable of suction/water permeability.
A suction/compression pipe that communicates with the compression means, a slurry extruder whose discharge section communicates with the molding space created by both of the molds, its drive motor, and a pressure signal that detects the pressure within the molding space. A pressure sensor is electrically connected to the pressure sensor and the drive motor, and the output signal value A of the pressure sensor is compared with the set pressure value B input in advance, and the drive signal is determined when the following equation (1) is satisfied. A slurry casting device characterized by comprising a controller that outputs a drive stop signal to a drive motor when Equation (2) is satisfied. A＜B …(1) A≧B …(2)