JPH0818320B2 - Extrusion molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auger type extruder for extruding plastic dough.

[0002]

2. Description of the Related Art A so-called plunger type molding machine and an auger type molding machine are known as an apparatus for continuously extruding a clay from a spinneret to produce a molded body. In an auger type molding machine, a screw in which blades are spirally attached to the outer circumference of a long cylinder rod is rotated, and the clay is extruded by this screw. FIG. 4 is a schematic cross-sectional view showing the periphery of a die of such an auger type extruder. In the inner space of the main body 4, in the lengthwise direction, the auger screw 5
Is rotatably fixed. The auger screw 5 is a slender cylinder rod having blades spirally attached to the outer periphery thereof. The cylindrical intermediate barrel 2 is attached to the tip of the main body 4, and the base 1 is attached to the tip of the intermediate barrel 2. The clay in the main body is pushed out of the main body 4 by the rotation of the auger screw 5, passes through the internal space 3 of the intermediate body 2, and is pushed out from the tip of the mouthpiece 1. In FIG. 4, the core metal is not shown.

On the other hand, recently, a solid oxide fuel cell (SOFC) has been attracting attention as a highly efficient and clean chemical power generator. In order to realize such an SOFC on a commercial scale, it is necessary to establish the manufacturing technology of its components. But,
Each constituent element of SOFC is ceramics, and advanced manufacturing technology is required to simultaneously satisfy various required characteristics such as dimensions, porosity, strength, and electrical characteristics. From such a standpoint, the present inventor has researched, among the constituent elements of SOFC, a manufacturing technique of an air electrode tube mainly made of a porous ceramic support tube or La _0.8 Sr _0.2 MnO ₃ .

[0004] For example, in the production of air electrode tubes made of La _0.8 Sr _0.2 MnO _3, first synthesized La _0.8 Sr _0.2 MnO ₃ material, the raw material is pulverized, drying the resulting powder. A binder and a pore-forming agent are added to the dried powder and kneaded, and the kneaded clay is formed into a tubular shape, dried and fired. At this time, from the viewpoint of productivity, the clay is extruded to form a tubular body.

As such an air electrode tube, a cylindrical one has been generally used. Further, recently, an air electrode tube having a special shape as shown in FIGS. 5 and 6 has also been proposed. The air electrode tube molded body 7 shown in FIG. 5 is formed by molding a flat partition 7b in the center of a cylindrical main body 7a. Oxidizing gas channel 8A,
8B is separated by partition 7b. In the air electrode tube molded body 17 shown in FIG. 6, a main body 17a constituting the outer shell thereof.
The shape in the width direction is a flat, substantially elliptical shape. The inner space of the main body 17a is partitioned by three plate-shaped partitions 17b, and four rows of oxidizing gas flow paths 18A, 18B, 18C, 18D are formed in parallel with each other. This type of SOFC
It is attracting attention because it can reduce the current flow in the circumferential direction and reduce the voltage gradient in the circumferential direction as compared with the conventional case.

[0006]

The inventor of the present invention produced a molded product having a shape as shown in FIGS. 5 and 6 in the process of developing a manufacturing technique for an air electrode tube. However, it has been found that an auger type extruder causes problems. That is, as shown in FIG. 7, when the molded body 7A was extrusion molded, twisting occurred, and the orientation of the flat plate-shaped partition 7b changed significantly between one end and the other end of the molded body 7A. In this case, when the oxidizing gas introducing pipe is inserted into the oxidizing gas passages 8A and 8B later, the oxidizing gas introducing pipe may not reach the end of the air electrode pipe.

Further, when the zirconia solid electrolyte membrane is attached to the outer surface of the air electrode tube by the EVD method, the solid electrolyte membrane does not attach much to the portion where the plate-shaped partition 7b exists. Therefore, when the plate-shaped partition 7b is twisted as shown in FIG. 7, a portion with a small amount of zirconia attached is formed in a spiral shape on the outer surface of the air electrode tube. In this case, it becomes difficult to attach the interconnector to the surface of the SOFC cell. Further, when the molded body is twisted, cracks are likely to occur in the drying stage and the firing stage.

When the molded body as shown in FIG. 6 is extrusion molded, the degree of twist of the molded body 17 is less than that in the case of FIG. However, that much strain remains inside the molded body 17. Therefore, water evaporates in the drying stage,
When the plasticity is lost, stress is generated inside the molded body, and the molded body is twisted. As a result, the same problem as described above occurs.

An object of the present invention is to prevent twisting and distortion of the extruded body when the extruded body is produced by an auger type extruder.

[0010]

SUMMARY OF THE INVENTION The present invention has a main body containing an auger screw, a cylindrical intermediate cylinder connected to the tip of the main body, and a mouthpiece connected to the tip of the intermediate cylinder. Then, an extrusion molding machine configured such that the clay that has been extruded from the main body by the rotation of the auger screw passes through the intermediate cylinder and is extruded from the mouthpiece, and at this time, the clay is formed into a predetermined shape. In the above, the present invention relates to the extrusion molding machine, wherein a regulating projection for regulating the rotation of the clay that has been extruded from the main body is provided on the inner wall surface of the intermediate barrel.

[0011]

1 is a schematic sectional view of an extrusion molding machine according to an embodiment of the present invention taken along its length, and FIG. 2 shows an intermediate barrel 2 of the extrusion molding machine of FIG. 1 in its width direction. It is a schematic sectional drawing cut | disconnected. The same functional members as those of the extrusion molding machine shown in FIG.

A cylindrical intermediate body 2 is attached to the tip of the main body 4, and a base 1 is attached to the tip of the intermediate body 2. A total of four flat plate-shaped projections 6 are arranged on the inner wall surface 2a of the intermediate body 2. These flat plate-like projections 6 are provided in parallel with the longitudinal direction of the intermediate body 2, and the flat plate-like projections 6 are provided on the inner wall surface 2a at equal intervals and at equal angles. Therefore, one set of flat plate-like projections 6 is aligned in a straight line, and another set of flat plate-like projections 6 is also aligned in a straight line, and the sets of flat plate-like projections 6 make an angle of 90 ° with each other.

According to such an extrusion molding machine, even if the clay which has been extruded from the main body 4 by the auger screw 5 is rotated, the flow of the clay is regulated by the flat projections 6, and the inner space 3 of the intermediate cylinder 2 is The rotation of the clay on the ground is blocked. The flow of the clay is extruded into the mouthpiece 1 while being restricted in the longitudinal direction of the intermediate body 2 in this manner, and then the mouthpiece 1
Extruded out of. Therefore, the twist of the extruded body extruded from the die 1 is reduced. Thereby, the dimensional deviation between one end and the other end of the extruded body can be reduced. For the same reason, cracks are less likely to occur during the drying and firing stages of the extruded body.

Particularly, when the SOFC porous ceramics support and the air electrode tube as shown in FIGS. 5 and 6 are molded by the extrusion molding machine of this embodiment, the partitions 7b and 17b are not twisted so much. Therefore, even when the oxidizing gas introducing pipe is inserted into the oxidizing gas passages 8A, 8B, 18A, 18B, 18C, 18D when the power generator is assembled, the oxidizing gas introducing pipe does not hit the partition. Also, when the zirconia solid electrolyte membrane is formed by the EVD method, the thin portion of the membrane does not spirally form around the outer periphery of the air electrode tube or the porous ceramic support in a twisted state. Further, there is no problem in forming the interconnector.

In the examples shown in FIGS. 1 and 2, the flat plate-shaped projection 6 is used as the restriction projection. However, as shown in FIG. 3, the needle-shaped protrusion 16 can also be used as a regulating protrusion. That is,
A plurality of needle-like protrusions 16 are arranged in a line in the lengthwise direction of the intermediate body 2, and two such needle-like protrusions are provided.
Even with such a configuration, the needle-like protrusions 16 arranged in rows
However, since the rotation of the clay that is extruded from the main body 4 is restricted, the above-described effect can be obtained.

In the example shown in FIGS. 1 and 2, the number of the flat plate-shaped projections 6 can be changed, but the effect is greater when three to four plates are provided. In the example of FIG. 3, the number of needle-like protrusion rows can be changed to, for example, three rows or four rows. Further, the shapes of these regulating projections can be changed, but it must be possible to prevent the rotation of the clay that is pushed out from the main body.

The height of such a restriction protrusion (for example, h shown in FIG. 2) is 1/20 or more of the width W of the internal space 3 of the intermediate body 2,
It is preferably 1/2 or less. If this is less than 1/20, the effect of regulating the rotation of the clay becomes poor. In addition, the sum of the lengths of such restriction protrusions (for example, l ₂ shown in FIG. 1)
Is preferably 1/10 or more of the length l ₁ of the intermediate cylinder 2 and 1 or less. If this is less than 1/10, the effect of regulating the rotation of the clay will be poor.

In each of the above-mentioned examples, the regulating projection is provided on the intermediate drum 2.
Was provided parallel to the length direction of the. However, there are cases where it is difficult to sufficiently control the flow of the clay, or the flow of the clay is insufficiently regulated because the intermediate barrel 2 is short. At this time, the restricting projections can be spirally arranged so as to rotate in the direction opposite to the rotation direction of the auger screw 5. As a result, a rotating force opposite to the rotating direction is applied to the cup soil that has entered the internal space 3.

Next, experimental results will be described. Using the auger type extrusion molding machine shown in FIGS. 1 and 2, the air electrode tube molding shown in FIG. 5 was produced. The number of flat plate-like projections 6 was four, and they were arranged as shown in FIGS. Length of the intermediate body 2
l ₁ was 200 mm, and the width of the internal space 3 was 100 mm. The molded body 7 has a length of 500 mm, a wall thickness of 2 mm, and an outer diameter of
It was set to 20 mm.

First, for La _0.8 Sr _0.2 MnO ₃ raw material powder,
Polyvinyl alcohol as a binder and cellulose as a pore-forming agent were added, and water was further added and kneaded. The clay thus obtained was put into the auger type extrusion molding machine shown in FIG. 1 or 4, and the auger screw 5 was rotated to extrude from the die 1 to obtain a molded body 7 shown in FIG. On this occasion,
The height h and the length l ₂ of the plate-like protrusion 6 were variously changed as shown in the table below. Then, the twist angle at one end and the other end of each extruded molded body 7 was measured. The results are shown in the table below.

[0021]

[Table 1]

Thus, by adopting the present invention,
The twist angle has decreased. In particular, it was found that when the height of the protrusions is 5 mm or more and the length is 20 mm or more, the twist angle sharply decreases. In this way, it is particularly effective if the height of the plate-like protrusions is 1/20 or more with respect to the width of the internal space of the intermediate cylinder and the length of the plate-like protrusions is 1/10 or more of the length of the intermediate cylinder. is there.

[0023]

As described above, according to the present invention, since the regulating projection for regulating the rotation of the clay which is extruded from the main body is provided on the inner wall surface of the intermediate cylinder, the rotation of the clay in the intermediate cylinder is prevented. It is blocked. Therefore, the twist of the extruded body made of the clay that passes through the intermediate cylinder and is extruded from the die is reduced. As a result, the dimensional deviation between the one end and the other end of the extruded body can be reduced, and the accuracy can be improved. Also, cracks are less likely to occur during the drying and firing stages of the extruded body.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of the vicinity of a die of an extrusion molding machine according to an embodiment of the present invention as seen in a lengthwise direction.

FIG. 2 is a schematic cross-sectional view of an intermediate cylinder of the extrusion molding machine of FIG. 1 as seen in a width direction thereof.

FIG. 3 is a schematic cross-sectional view of the vicinity of a die of an extrusion molding machine according to another embodiment as seen in the lengthwise direction.

FIG. 4 is a schematic cross-sectional view of the vicinity of a die of a conventional extrusion molding machine as seen in the lengthwise direction.

FIG. 5 is a perspective view showing an example of a molded air electrode tube.

FIG. 6 is a perspective view showing another example of a molded air electrode tube.

FIG. 7 is a perspective view showing an air electrode tube molded body 7A in which a partition 7b is twisted.

[Explanation of symbols]

 1 Mouth 2 Intermediate barrel 2a Inner wall surface of intermediate barrel 3 Internal space of intermediate barrel 4 Main body 5 Auger screw 6 Plate-shaped protrusion 7,7A, 17 Air electrode tube molded body 7b, 17b Plate-shaped partition 8A, 8B, 18A, 18B, 18C, 18D Oxidizing gas flow path

Claims (3)

[Claims] 1. A main body having a built-in auger screw, a tubular intermediate cylinder connected to the tip of the main body, and a mouthpiece connected to the tip of the intermediate cylinder. The clay which has been extruded from the main body passes through the intermediate cylinder and is extruded from the mouthpiece, and at this time, the clay is extruded from the main body in an extrusion molding machine configured to be formed into a predetermined shape. An extrusion molding machine, characterized in that a regulating projection for regulating the rotation of the clay is provided on the inner wall surface of the intermediate body. 2. The extrusion molding machine according to claim 1, wherein the regulating protrusion is a flat plate-shaped protrusion or a needle-shaped protrusion. 3. The height of the restriction projection is 1/20 or more and 1/2 or less of the width of the internal space of the intermediate cylinder, and the total length of the restriction projections is 1/10 for length
The extruder according to claim 1, which is 1 or more and 1 or less.