JPH01178402A - Manufacture of hollow molding - Google Patents

Abstract

PURPOSE:To shorten a period of time required for manufacture, by a method wherein molding in a plaster mold are dried forcibly by controlling a difference between thicknesses of moldings by performing control of the thickness of the hollow moldings through volume of water absorbed by the plaster mold from slurry. CONSTITUTION:When valves 24a, 24b, 24g are opened by giving compressed air within a feed tank 11 by opening a valve 24c, slurry in the feed tank 11 is fed with pressure within an inner hole 13d of a plaster mold 13. The slurry is introduced into a cylinder up to a predetermined height by controlling opening and closing of a valve 24f at a point of time when the slurry has arrived at a peep plate 16a, the valve 24b is closed, and valves 24d, 24e are opened. In the case where pressure feed of a predetermined quantity of the slurry within the inner hole 13d of the plaster mold 13 has been performed through the inside of the cylinder 12, the valve 24g is closed immediately, a pressure plate 14b is slackened, a valve 24h is opened and then the slurry within the inner hole 13d in an unsettled state is discharged. A valve 24h is closed, a valve 24i is opened and warm air is given within the inner hole for a predetermined period of time through a warm air generator 15. A stuck ceramic pipe is dried within the hole 13d, released from the plaster mold 13 and taking-out becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing hollow molded articles from ceramic slurry.

<Prior art> -m, as shown in FIG. 4, the slurry pressure casting device used for manufacturing the above-mentioned hollow molded product has a plaster mold 2 for casting erected by a support member 1, and a molding mold. A supply container 4 containing a slurry for use in the plaster mold 2 and communicating with the plaster mold 2 via a conduit 3 is provided, and the slurry in the supply container 4 is pressurized and supplied into the plaster mold 2 for casting. There is.

In such a casting device, water in the slurry supplied into the plaster mold 2 is gradually absorbed into the plaster mold 2, and when the deposited thickness reaches a predetermined thickness, the plaster mold is molded. Unattached slurry is discharged from inside 2.

The hollow molded product formed by filling is then air-dried in the plaster mold 2, then released from the mold, dried, and subjected to appropriate heat treatment.
It is used for firing etc.

(Problem to be Solved by the Invention) Incidentally, in this manufacturing method, it is important to make the wall thickness of the hollow molded product a predetermined thickness, but in the past, slurry was constantly supplied from the supply container to the right front mold. The wall thickness is adjusted by adjusting the casting time. However, when darning is used, differences in the wall thickness between molded products often occur due to differences in the mixing lot of slurry or variations in the water absorption and adsorption capacity of the plaster mold. It took a long time to dry inside the plaster mold.

Therefore, an object of the present invention is to suppress the difference in wall thickness between molded products as much as possible by adjusting the wall thickness of the hollow molded product by adjusting the volume of water that the plaster mold actually absorbs from the slurry. This is an attempt to shorten the time required for manufacturing by forcibly drying the molded product inside the plaster mold.

(Means for Solving the Problems) The present invention provides a method for manufacturing a hollow molded product in which a slurry is supplied into a plaster mold for casting to form a hollow molded product. The slurry is supplied according to the decrease in water content in the slurry, and when the supply amount of slurry reaches a predetermined volume, the supply is stopped and the unattached slurry in the plaster mold is discharged. This method is characterized in that hot air is supplied into the mold to dry the hollow molded product adhering to the mold, and then taken out from the mold.

(Actions and Effects of the Invention) In this manufacturing method, the moisture of the slurry filled in the plaster mold is absorbed by the plaster mold and gradually becomes fleshy, reducing the volume (moisture) in the plaster mold. is gradually reduced, and a volume of slurry corresponding to this reduction is supplied, and an amount of slurry corresponding to this supply volume is deposited on the plaster mold.

Therefore, if the supply of slurry to the plaster mold is stopped when the supply amount of slurry reaches a predetermined capacity, and the unattached slurry is promptly discharged from the plaster mold, the thickness of the deposit inside the plaster mold can be reduced. is always approximately constant, and there is almost no difference in wall thickness between the resulting molded products. In addition, since warm air is supplied into the plaster mold after the unattached slurry has been discharged, the molded product inside the plaster mold is forcibly dried, which shortens the drying time. The time required for manufacturing a hollow molded article can be shortened.

(Embodiments) (1) Casting Apparatus A casting apparatus suitably employed in the manufacturing method of the present invention is shown in FIG. The casting device includes a supply tank 11, a cylinder 12, a plaster mold 13, a support mechanism 14, and a hot air generator 1.
5, the supply tank 11, the cylinder 12 and the plaster mold 13 are connected by a first conduit 21 and a second conduit 22, and the plaster mold 13 and the hot air generator 15 are connected by a third conduit 2.
Connected by 3.

The supply tank 11 is a known supply container that accommodates a large volume of slurry, and is equipped with an agitator 11a that uniformly stirs the contained slurry. A first conduit 21 is connected to the center of the bottom of the supply tank 11 via a connecting pipe 11b. The cylinder 12 is a second supply container containing a small volume of slurry, and is made of transparent plastic with a volume scale.As shown in FIG. It is sandwiched and supported in the vertical direction by 12b and 12c. The cylinder 12 is connected to the first conduit 21 and the second conduit 22 via a connecting tube 12d provided on the lower flange 12c. Each connecting pipe 11b, 12d has first and second on-off valves 2.
4a and 24b are interposed. In addition, in such a cylinder 12, the connecting pipe 1 provided on the upper flange 12b
It is connected to the fourth conduit 25 via 2e. This fourth
The conduit 25 is connected to a connecting pipe 11d provided on the lid 11c of the supply tank 11 and connected to the compressor. Each connecting pipe lid, 12e has third and fourth on-off valves 24c, 24d, and fifth and sixth on-off valves 24e, 24.
f is interposed.

The plaster mold 13 is a rectangular cylindrical piece made by integrating a pair of vertically divided molds 13a and 13b with a plurality of clamps 13c as shown in FIG. It is provided with a hole 13d.

Therefore, if the clamp 13c is removed, both molds 1 and 1 plaster mold 13 can be removed.
It can be divided into 3a and 13b. In this plaster mold 13, the support mechanism 14 is sandwiched and erected between the lower base 14a and the pressing plate 14b, and a transparent plastic viewing plate 16 is provided between the upper surface of the plaster mold 13 and the pressing plate 14b.
A and a rubber seal plate 16b are interposed. A connecting pipe 14c is provided on the lower surface of the lower stand 14a, and this connecting pipe 14c is connected to the seventh, eighth, and ninth on-off valves 24.
g, 24h, and 24i, and are fluid-tightly connected to the lower end of the inner hole 13d of the plaster mold 13 and connected to the second conduit 22 and the third conduit 23.

The hot air generator 15 includes a compressor 15a and a heating section 15b.
The air supplied by the compressor 15a is heated by the heater in the heating section 15b to a temperature of 40 to 60°C, and then passed through the third conduit 23 to the stone/receptacle mold 13.
It is supplied into the inner hole 13d of.

In a casting apparatus having such a configuration, a ceramic slurry is stored in the supply tank 11 and stirred homogeneously prior to casting, and all the on-off valves are closed. Further, the cylinder 12, the plaster mold 13, and the hot air generator 15 are connected as shown in FIG.

Then, the third on-off valve 24c is opened to apply compressed air to the upper surface of the slurry in the supply tank 11 to pressurize it, and the first, second and seventh on-off valves 24a, 24b, 2
When 4g is opened, the slurry in the supply tank 11 is pumped into the inner hole 13d of the plaster mold 13 through the first and second conduits 21.22.

When the slurry in the inner hole 13d reaches the viewing plate 16a, the sixth opening/closing valve 24f is adjusted to introduce the slurry to a predetermined height into the cylinder 12, and then the second opening/closing valve 24b is closed and the sixth opening/closing valve 24f is adjusted to introduce the slurry to a predetermined height. 4. Fifth opening/closing valve 24d
, 24e.

As a result, the pumping of the slurry into the supply tank 11 is stopped, and thereafter the slurry is pumped from the cylinder 12. When the slurry in the cylinder 12 drops to a predetermined height, that is, a predetermined amount of slurry is deposited in the inner hole of the plaster mold 13.
3d, the seventh on-off valve 2 is immediately opened.
4g, loosen the pressing plate 14b, and close the eighth
Opening/closing valve 24h is opened to discharge unattached slurry in inner hole 13d. After mud removal, the eighth on-off valve 24h is closed, and the ninth on-off valve 24i is opened, and warm air of 40 to 60°C is supplied from the hot air generator 15 to the inner hole of the plaster mold 13 for a predetermined period of time through the third conduit 23. Granted within 13d. As a result, the ceramic pipe attached within the inner hole 13d is dried and can be released from the plaster mold 13 and taken out.

By the way, from inside the cylinder 12, the inner hole 13d of the plaster mold 13
The relationship between the supply amount V (cc) of slurry supplied into the interior and the wall thickness t (cm) of the hollow molded product is expressed by the following equation.

Do=outer diameter of molded body (cm) β: length of molded body (cm), stomach. : Moisture content of slurry (wt%) Wl: Moisture content of molded body immediately after slurry removal (wt%) Therefore, the amount of slurry in the cylinder 12 to be supplied into the inner hole 13d of the plaster mold 13 is calculated based on the value of (■) calculated in advance. If this is controlled, the wall thickness t of the obtained molded product will be a predetermined value, and there will be almost no difference in wall thickness between the molded products.

(2+ gi experiment using ceramic slurry with a moisture content of 15 wt%.
mm, wall thickness 7mm, length 1500mm, density 2.6g/
cm3, the pipe with a molded body moisture of 9wt% immediately after mud removal is the first pipe.
It was molded using the casting equipment shown in the figure. What is the amount of slurry supplied from the cylinder into the inner hole of the plaster mold during molding? , 70cc. Further, the temperature of the hot air blown from the hot air generator was about 50° C., the wind speed inside the inner hole of the plaster mold was In/sec, and the blowing time was about 1 hour. Table 1 shows these molding conditions and the wall thickness of the molded product. Table 2 shows the results of molding pipes similar to those described above using the casting apparatus shown in FIG. 4 and adjusting the wall thickness by adjusting the casting time as a comparative example. Regarding the quality of the wall thickness of each molded product in the table, those within the range of (7±1) mm were evaluated as good, and those outside of this range were evaluated as failed. 1st
In the example according to the present invention shown in the table, the time required for one cycle from the start of the first production to the start of the second production is at most about 2 hours, whereas the comparison shown in Table 2 In the example, the time required for one cycle is 5 to 6 hours.

Table 1 (Example) Table 2 (Hisame Example) Referring to these results, if the manufacturing method of the present invention is adopted, all the wall thicknesses of the molded product will fall within the range of (7±l) mm, Moreover, this can be controlled by an extremely easy means of supplying a constant volume of slurry, whereas when conventional manufacturing methods are used, there is a large variation in wall thickness between molded products (7
) mm, and the casting time must be adjusted each time, which is extremely troublesome, and furthermore, the time required for manufacturing is also long.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a casting device employed in a manufacturing method according to an embodiment of the present invention, FIG. 2 is an enlarged partial longitudinal sectional side view of a cylinder in the same device, and FIG. 3 is a gypsum casting device in the same device. FIG. 4, which is an enlarged perspective view of the upper part of the mold, is a schematic configuration diagram of a conventional casting device. Explanation of symbols 11... Supply tank, 12... Cylinder, 13...
- Gypsum mold, 14... Support mechanism, 15... Hot air generator, 21-23. 25... Conduit.

Claims (1)

[Claims] In a method for manufacturing a hollow molded article in which a slurry is supplied into a plaster mold for casting to form a hollow molded article, after filling the plaster mold with slurry, the slurry is added in accordance with the amount of water reduction in the slurry in the mold. When the amount of slurry supplied reaches a predetermined volume, the supply is stopped and the unattached slurry in the plaster mold is discharged, and then hot air is supplied into the plaster mold to make the slurry adhere to the inside of the mold. A method for manufacturing a hollow molded article, which comprises drying the hollow molded article and then taking it out from the same mold.