JP2011194791A - Soil kneading machine and method of extrusion-molding body by soil kneading machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soil kneading machine capable of avoiding the problem that wrinkling occurs on the inside surface of a cylindrical extrusion molding in the process of drying the cylindrical extrusion molding vertically by the soil kneading machine, leading to cracking with the wrinkle as the starting point and a method of extrusion-molding a body by the soil kneading machine.SOLUTION: In the process of manufacturing a ceramic product, e.g., a porcelain bushing, a nozzle having a cylindrical extrusion passage 4 formed with an outside-diameter nozzle 2 and an inside-diameter nozzle 3 is provided at an extrusion outlet of the soil kneading machine used to obtain a cylindrical body formed by extruding a body in a cylindrical form which is prepared by mixing and kneading together molding raw materials containing ceramic materials, and a ring part 5 protruded in the outer peripheral direction is formed at the end of the inside-diameter nozzle 3 on the side of extrusion.

Description

  The present invention relates to a clay kneader and a method for extruding clay by a clay kneader.

  Moisture suitable for molding after mixing and kneading the molding raw material containing ceramic material into a clay and extruding it into a cylindrical shape with a kneader and cutting it to the desired length in the manufacturing process of ceramic products such as firewood pipes Conventionally, a method of conducting current drying until it becomes is adopted (for example, Patent Document 1).

  FIG. 2 shows a base structure used in a conventional kneader. A cylindrical clay extruded using a conventional base as shown in FIG. 2 is dried in an upright state (hereinafter referred to as longitudinal drying) so that the inner diameter portion is vertical.

  However, the conventional vertical drying has a problem that the inner diameter surface is swollen by the moisture generated from the product and the wrinkles are generated, and cracks are generated starting from the wrinkles, causing a product defect.

  The reason for this is not necessarily clear, but the vertical drying is performed by grounding the cylindrical lower end of the cylindrical clay extruded from the base shown in FIG. 2 on the pallet, and one end of the inner diameter is closed by the pallet. When a slight wrinkle is formed on the inner diameter surface that is difficult to dry due to poor circulation and compression stress due to its own weight, cracks originating from the wrinkle occur due to the tensile stress in the circumferential direction that acts in the subsequent drying shrinkage process It is presumed that they will do.

JP-A-5-148003

  The object of the present invention is to solve the above-mentioned problems and avoid the problem that cracks are generated starting from the wrinkles on the inner surface in the process of longitudinal drying of the cylindrical extruded body by a kneader. The present invention provides a kneading machine and a method for extruding clay by a kneading machine.

  The kneading machine of the present invention made to solve the above problems is a kneading machine having a die having a cylindrical extrusion channel formed by an outer diameter die and an inner diameter die at an extrusion port. The extrusion-side tip portion is provided with a ring portion protruding in the outer peripheral direction.

  The invention according to claim 2 is characterized in that, in the kneader according to claim 1, the ring portion is projected by 1 to 2 mm in the outer peripheral direction.

  The invention described in claim 3 is a method of extruding clay by the kneader according to claim 1 or 2, wherein the ring portion is formed on the inner surface of the cylindrical clay extruded toward the outlet portion of the die. A compressive force is applied to form a compressive stress layer.

  The clay kneader according to the present invention has a die having a cylindrical extrusion channel formed by an outer diameter die and an inner diameter die at an extrusion port for extruding clay from the clay kneader, and an extrusion side tip of the inner diameter die. With the structure including the ring part in the part, a compressive force is applied from the ring part to the inner surface of the cylindrical clay extruded toward the outlet part of the base, and a compressive stress layer is formed on the inner surface. In this way, it is possible to avoid generation of wrinkles in the vertical drying process and generation of cracks starting from the wrinkles by increasing the density of the inner diameter surface and exerting a pressing effect and improving the smoothness of the inner diameter surface. did.

It is a nozzle structure used in the clay machine of this embodiment. It is a base structure used for a conventional clay machine.

  Preferred embodiments of the present invention are shown below.

  A base 1 shown in FIG. 1 is provided at the outlet of the clay mill. The base 1 has a cylindrical extrusion channel 4 formed by an outer diameter base 2 and an inner diameter base 3, and includes a ring portion 5 that protrudes in an outer peripheral direction at the distal end portion of the inner diameter base 3 on the extrusion side. .

  As shown in FIG. 1, the outer diameter base 2 is made of a drum-shaped metal obtained by bending the distal end portion on the outlet side in the outer peripheral direction.

  The inner diameter base 3 is made of a columnar metal, is attached to the tip of a screw in a conventional clay mill, and is arranged so that the central axis of the cylinder coincides with the central axis of the outer diameter base 2.

  Since the ring portion 5 is welded to the distal end portion of the inner diameter base 3 and protrudes 1 to 2 mm in the outer peripheral direction, the cylindrical extrusion flow path 4 formed by the outer diameter base 2 and the inner diameter base 3 is connected to the ring portion. It is narrowed down by 5. Therefore, when the clay passes through the squeezed extrusion flow path 4, a compressive force is applied to the inner diameter surface from the ring portion 5, and a compressive stress layer is formed on the inner diameter surface. Here, if the protrusion amount of the ring portion 5 is small, the formation of the compressive stress layer becomes insufficient, and conversely if the protrusion amount is large, the change in the contraction rate of the product becomes large, which is not preferable.

  The present invention is suitable for extrusion molding of an outer diameter base 2 having an outer diameter of 500 mm to 1900 mm and a cylindrical clay having an inner diameter of 80 mm to 500 mm.

  As described above, the cylindrical clay extruded by the kneader of the present invention was subjected to a drying process in a conventionally known electric drying process. In the electric drying process, vertical drying was performed. In the present embodiment, the bottom end of the cylinder is grounded on the punching metal disposed on the pallet, and the eyelet electrode is attached to the top end of the cylinder, and then current is passed between the punching metal and the eyelet electrode to perform energization drying. It was.

  As described above, in the vertical drying process as shown in FIG. 2 in which the cylindrical lower end portion of the cylindrical clay extruded from the conventional base having no ring portion is grounded on the pallet, Since one end of the cylinder is clogged with a pallet, the air flow becomes worse, and wrinkles are formed on the inner diameter surface of the extruded product in the drying shrinkage process. was there.

  On the other hand, in the present invention, by using the die shown in FIG. 1, the density of the inner diameter surface is increased, the pressing effect on the inner diameter surface works to improve the smoothness of the inner diameter surface, and the generation of wrinkles in the drying process, Generation of cracks starting from the wrinkles can be effectively avoided.

  When the conventional base shown in FIG. 2 is used and the frequency of product defects when the base of the present embodiment shown in FIG. 1 is compared, the product of the present embodiment is obtained by using the base of the present embodiment. The incidence of defects was reduced from 3.4% to 2.2%.

1 Base 2 Outer Diameter Base 3 Inner Diameter Base 4 Extrusion Channel 5 Ring

Claims (3)

  In the kneader having a die having a cylindrical extrusion flow path formed by an outer diameter die and an inner diameter die at the extrusion port, a ring portion protruding in the outer peripheral direction is provided at the extrusion side tip portion of the inner diameter die. A kneading machine characterized by that.   The kneading machine according to claim 1, wherein the ring portion is protruded by 1 to 2 mm in the outer peripheral direction.   3. A method of extruding a clay by a clay kneader according to claim 1 or 2, wherein a compressive force is applied from the ring portion to the inner surface of the cylindrical clay extruded toward the outlet portion of the die. A method for extruding clay by a kneader characterized by forming

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