JPS605443B2 - Method for manufacturing ceramic melting crucibles, especially glass melting crucibles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic melting mold, especially a glass melting mold, in which a ceramic material is charged into a mold and shaped into a desired shape. Concerning drying formats.

As is well known, glass melting machines and graphite melting machines are used to melt glass, non-ferrous metals, and the like.

Conventionally, such containers have been manufactured by manual methods as described below. The main raw materials, ie, ceramic materials, are potter's clay, fireclay, and additionally graphite and silicon carbide. During production, raw materials are mixed or charged into a kneading machine and moistened to form a uniform structure. Subsequently, this material is subjected to a predetermined processing and then supplied to a vacuum continuous press machine to be cut into a predetermined length. The material cut into a predetermined length weighs approximately 9 to 10k9,
It is loaded into the mold by hand.

In this case, care must be taken to prevent air bubbles from forming within the material. Conventionally, such a method has provided the best uniformity of compaction of the bottom of the container. In this method, two-thirds of the material required for the manufacture of the container is first charged into the mold.

In the next step, a U-shaped iron head is pressed onto the material that has been injected into the mold in the previous step. This causes some of the material to be forced upwardly between the legs of the U-shaped iron head and the mold, thereby forming the bottom of the container and the surrounding wall near the bottom. In this case, care must be taken that the wall thickness of the bottom of the container and the wall thickness of the peripheral wall near the bottom are kept at predetermined values. The remaining 1/3 of the material required for manufacturing is added to the upper part of the container wall between the inner surface of the mold and the legs of the U-shaped iron head in a further process. is charged to. The mold for the container is
It consists of a bottomless wooden tube, which is held in place by iron rings. This cylinder is placed on the floor, and the material is separated from the floor by paper placed underneath. To prevent the material from adhering to the walls of the cylinder, a damp cloth is placed over it.This cloth can be easily removed later during molding of the material. Then place a damp cloth over the top to prevent it from drying too quickly and causing cracks.

The side walls and bottom of the material are struck with a rubberized wooden tool six times at timed intervals within two weeks.

This provides good compression of the sidewall and bottom material. Approximately three weeks after the molding, the container solidifies and is removed from the mold.

Polish the inside and outside of the container and remove the corners at the same time. A cloth is further applied to prevent the walls of the container from drying out too quickly, and this cloth is gradually removed over the next week. After about 2-3 months, the containers will become even drier and harder and can be transported into storage.

A storage period of 6 months is necessary in this storage chamber, so that the containers are evenly and finally dried and contain only a small amount of moisture. The container is now ready for use. It is an object of the present invention to mechanically manufacture a container with a closed bottom and open to one side for use as a ceramic melting container, in particular as a glass melting container, which can be manufactured by hand in the conventional manner. The uniform pressure distribution within the ceramic material should be at least equal to that of the container, with a uniform pressure distribution within the cylindrical wall portion of the container as well as within the bottom, with the connection between the wall portion and the bottom being weakened. The aim is to provide a manufacturing method that does not require

The gist of the present method for achieving this purpose is to produce a ceramic melting mold, in which ceramic material is charged into a mold, shaped into a desired shape, and then dried. In this type, the ceramic material is charged into an almost completely closed mold by means of a vertical ceramic continuous press, in which the cylindrical wall of the vortex is connected to the stationary core of the mold. Immediately after this, without interrupting the flow of the ceramic material, the closed bottom is pressed and this insert T'
During the pressing of the bottom part, the stationary mold, including the core, is moved in the direction of charging the ceramic material.

According to the method of the invention, the bottom can be pressed next to the cylindrical wall part of the container, so that no problems arise at the connection from the cylindrical wall part of the container to the bottom, i.e. the entire container. The glass is compressed and extruded almost uniformly, so that the entire container has a uniform structure, so there are no weakened spots that could cause breakage or crack during use. This is especially noticeable when manufacturing kanji, which reduces the molding time to a few minutes and eliminates the possibility of scratches due to mechanical failure, uneven compression or uneven structure throughout the container. Occurrence is prevented. In one embodiment of the invention,
At the end of the pressing process of the bottom, a narrow annular gap is created between the mold and the mouthpiece of the continuous press, through which the cutter is passed, thereby removing the bottom from the ceramic material in the mouthpiece. Separate.

At this time, the continuous press machine is stopped. This completes the pressing process. It is advantageous if the transition from stationary support to movement of the mold is controlled as a function of the pressure value within the mold.

This ensures that the material, in particular at the connection between the cylindrical wall part and the bottom of the container, is always compressed in the same manner. In order to ensure uniform compaction of the cylindrical wall section and the bottom, it is advantageous for the continuous press to always charge a constant amount of ceramic material. According to this, the ceramic material is uniformly evacuated. The apparatus for carrying out the manufacturing method of the present invention has a mold for manufacturing containers, and this mold mainly consists of an outer wall and a core, and further comprises a continuous press. The outlet of the continuous press, for example the mouthpiece, can be fitted with a mold, and a cutter is arranged in the area of the outlet.

With this device, first the cylindrical wall of the container is pressed, then the bottom is pressed, and after the pressing is finished, the bottom is cut from the material on the mouthpiece side at a point between the mold and the mouthpiece. be done. This cut surface forms the bottom of the container. The outer wall and core of the mold are movably arranged relative to the mouthpiece of the continuous press.

The core of the mold can be connected to the press table of a continuous press and can be provided with stationary stops to temporarily support the outer walls of the mold. This stop holds the outer wall of the mold in place so that the separated containers can be lowered together with the press table onto the press table. After this, the container can be received in a further device for removal. The press table that supports the core of the mold is
It is advantageous to provide a lowering device with a hydraulic cylinder that can be controlled in relation to the pressure in the mold. The inner diameter of the outer wall of the mold can also be larger than the outer diameter of the mouthpiece, in which case the core end face facing the bottom of the container can be moved as far as the exit plane of the mouthpiece.

In this case, it is necessary to provide a slight play between the mouthpiece and the outer wall of the mold. It is advantageous if the outside diameter of the press table is larger than the inside diameter of the outside wall of the mold and this press table forms part of the wall of the mold, in which case the press table rests against the edge of the outside wall of the mold. This outer wall is supported during the pressing of the cylindrical wall portion and bottom of the container.

The invention will now be explained with reference to the illustrated embodiment.

FIG. 1 shows the frame of a continuous press 2 for extruding ceramic material 16 from top to bottom, the continuous press 2 being equipped in a known manner with a mouthpiece 3. It is arranged within the upper transverse beam 4. Also assigned to the continuous press 2 is a press table 5, which is mounted on a hydraulic cylinder 6 so as to be able to move up and down. A control device for moving the press table 5 up and down is not shown.
The ceramic material is extruded into the mold through the mouthpiece 3, which is composed of an outer wall 7 and a core 8, which is supported on and fixed to the press staple 5. has been done.

The outer wall 7 can also be supported on the press table 5. The outer wall 7 is movably arranged. This outer wall 7 can be pressed against the mouthpiece 3 by the press table 5 and can be lowered to form a gap 9, at which the cutter 0 is exposed. It can be moved to cut ceramic materials. The press table 5 with its core 8 is shown in the lowered position in FIG.
has been lowered into a lowered position, so that the container 11 is separated from the outer wall 7, after which it is received in a further device, not shown, for removal.

2, 3 and 4 show the steps in the production of a container 11 having a cylindrical wall section 12 and a closed bottom 13. In FIGS.

As shown in FIG. 2, the press table 5 is moved upwardly in the direction of the arrow 14 via the hydraulic cylinder 6 so that the outer wall 7 rests against the mouthpiece 3 of the continuous press 2. To simplify the drawing, only the ends of the continuous press 2 and the conveying screw 5 are shown. The core 8 is fixed to the press table 5 so as to be adapted to this entry position. The evacuated and compressed ceramic material 16 is forced into the closed mold formed by the outer wall 7, the core 8 and the press table 5 as indicated by the arrow.

In this case, the mold has already been evacuated, so that the part of the mold which forms the cylindrical wall part 12 is filled with ceramic material 16 completely without gaps over its entire circumference. As soon as the ceramic material 16 has been filled into this mold part, which forms the cylindrical wall part 12, the hydraulic cylinder 6 is unlocked. As a result, the press table 5, together with the core 8 and the outer wall 7, is lowered by a predetermined small amount, as can be seen in FIGS. 2 and 3. During this time, the ceramic material continues to be supplied from the mouthpiece 3 for pressing the container bottom 13. At this slightly lowered position, a gap 9 of the required size is formed, the press table 5 is locked again,
It is then passed through a cutter 10 to cut the lower surface of the bottom 13 of the container 11 from the upper ceramic material. In this case, the outer wall 7 of the mold rests against a stationary stopper 17, and the outer wall 7 remains in this position, while the press table 5 is lowered further downwards to the position shown in FIG. After this, the container 11 is received in a further device, not shown, for transport. Subsequently, the press table 5 with the core 8 is moved upward again. At this time, the press table 5 first receives the outer wall 7 of the mold and is raised from the stopper 17, so that the mold is pressed against the mouthpiece. The above working steps are then repeated anew. The ceramic material continuous press 2 used for extruding the ceramic material used in the present invention is designed to have a constant extrusion pressure, and this extrusion pressure is not variable but constant.

By the way, when the cylindrical wall portion of the container is press-molded, a relatively large amount of friction occurs along the wall surfaces of the core 8 and the outer wall 7, and this friction also generates a large wall shear stress.

This is because the ceramic material is forced downwardly in the gap between the mold core 8 and the outer wall 7 against the above-mentioned friction. This wall shear stress due to friction acts in a direction opposite to the extrusion pressure. The high wall shear stress therefore serves to reduce the degree of compaction of the ceramic material in the cylindrical wall section of the container compared to what would be possible due to the construction and design of the ceramic continuous press itself.
By the way, after the press forming of the cylindrical wall portion 12 is completed, the bottom portion 1
Assuming that the outer wall 7 and the core 8 of the mold remain stationary during the pressing of step 3, the pressing of this bottom part 13 results in a significantly smaller cross-sectional area. Only wall period shear stress occurs.

This is because, while the continuous ceramic material is filled over the entire cross section of the base 13, only a small portion of the inner wall surface of the mold (outer wall 7) generates a correspondingly small wall shear stress. This is because it is not too much. This small wall shear stress hardly reduces the degree of compaction possible with the ceramic continuous press, so that the bottom 13 of the container is compressed significantly more strongly than the cylindrical wall section 12. . This results in the bottom part 13 having a higher degree of compression than the cylindrical wall part 12 and the cylindrical wall part 12 having a lower degree of compression than the bottom part 13. This is extremely harmful when the container is used as a melting device, especially as a glass melting device. ``There is a risk that the connection between the cylindrical wall part 12 and the bottom part 13 will develop cracks and perforations by the melt, leading to destruction, so that the container will not only become unusable; For the above reasons, it is important that the bottom part 13 and the cylindrical wall part 12 of the tube have a uniform degree of compression. It is extremely important to have a strong organization.

According to the invention, during the pressing of the bottom part 13 of the mold, the outer wall 7 and the core 8 of the mold are made such that the degree of compression of the bottom part 13 is approximately equal to the degree of compression of the cylindrical wall part 12. , moved in the direction of extrusion of the ceramic material.

As a result, Kanka has a uniform degree of compaction as a whole, and therefore a uniform material structure, and therefore can also have good heat resistance. The device for carrying out the method of the invention can also be constructed differently from the embodiment shown, for example the core 8 itself can also be run into the ceramic material in the direction of the arrow 14.

Furthermore, the inner diameter of the outer wall 7 of the mold may be slightly larger than the outer diameter of the mouthpiece 3. In this case,
The outer wall 7 together with the core 8 can run deep into the area of the mouthpiece 3. According to the invention, one-sided open containers with a closed bottom can be manufactured continuously in a short time, while at the same time maintaining a uniform distribution of the ceramic material between the cylindrical wall part 12 and the bottom part 13. Compression is obtained.

No problems arise at the connection between the wall part and the bottom part. The molding time, which takes approximately one day, is reduced to a few minutes. According to the present invention, the diameter of about 60 m to 150 m and about 6 m to 12 m.
It is possible to produce a glass melting vortex with a wall thickness of zero.

[Brief explanation of the drawing]

1 is a front view of a manufacturing apparatus according to an embodiment of the present invention, FIG. 2 is a partial view showing one working step of the manufacturing apparatus of FIG. 1, FIG. 3 is a partial view showing another working step, and FIG. FIG. 4 is a partial diagram showing yet another work step. DESCRIPTION OF SYMBOLS 1...Frame, 2...Continuous press machine, 3...Mouthpiece, 4...Horizontal beam, 5...Press table, 6...
Hydraulic cylinder, 7...Outer wall, 8...Core, 9...Gap, 10... Cutter, 11... Container, 12... Wall portion, 13... Bottom,
14...Arrow, 15...Transportation screw, 16...
Ceramic material, 17... stoppa. F"9.7Fne.2 Fyu3 Fyen.ku

Claims (1)

[Claims] 1. A method for manufacturing a ceramic melting crucible, in which ceramic material is charged into a mold, shaped into a desired shape, and then dried, using a continuous ceramic press machine that performs pressing in the vertical direction. The ceramic material is charged into an almost completely closed mold, the cylindrical wall part of the crucible being pressed through the stationary core and the stationary outer wall of the mold, immediately after which the flow of the ceramic material begins. The closed bottom is pressed without interruption, during which the mold, which has been stationary during the pressing of this bottom, is moved, including the core, in the direction of charging the ceramic material. A method for manufacturing a ceramic melting crucible.