JP4694857B2 - Screw for extruder and screw-type extruder using the same - Google Patents

Description

  The present invention relates to a screw structure of a screw type extruder that is suitably used for manufacturing ceramic clay.

  Conventionally, as shown in FIG. 6, a screw type extruder 1 in which a screw 9 having a drive shaft 5 and a flight 7 formed on the drive shaft 5 is arranged inside a hollow cylindrical body portion 3 has been proposed. (For example, see Patent Document 1 and Patent Document 2). The screw type extruder 1 shown in FIG. 6 has a spiral flight 7 continuously arranged so as to wind the surface of the drive shaft 5 and a plurality of fan-shaped flights 8 arranged intermittently. The screw 9 is provided, and is sometimes referred to as a kneader (earth kneader). Its essential function is to compress an object to be processed containing powder with a screw 9 and discharge it as a high-density compressed object.

  In the case of the screw-type extruder 1 shown in FIG. 6, when the drive shaft 5 is rotationally driven by a driving force transmitted from a driving means (for example, an electric motor or the like, not shown), a charging port (not shown) is used. To be processed, including the powder charged into the body portion 3, is pushed forward while being compressed by the flights 7 and 8 of the screw 9, and the high-density compressed material is cylindrical from the discharge port 11. Are continuously discharged.

Such a screw type extruder is suitably used for the production of ceramic clay using, for example, a mixture of ceramic powder, a dispersion medium, a binder and the like as an object to be processed.
JP-A-9-94818 Japanese Patent Laid-Open No. 10-100131

  However, there are few conventional screw type extruders having a sufficient kneading function, and the characteristics (for example, density, component composition, moisture content, etc.) in each part of the obtained compressed product become non-uniform, There has been a problem that the distribution varies, or a lot of screw marks are formed inside the obtained compressed product, and the clay becomes discontinuous.

  This problem appears as a particularly serious problem when the ceramic clay obtained by the screw type extruder is used as a raw material for extrusion molding of a porous honeycomb filter. Specifically, when a ceramic clay with non-uniform density and uneven distribution is used as a raw material for extrusion, the porosity of the porous honeycomb filter, which is the final product, becomes non-uniform and the distribution varies. Will occur. As a result, the performance (such as mechanical strength and filtration performance) of the porous honeycomb filter may be adversely affected.

  Moreover, when a ceramic clay having a large number of discontinuous parts (screw marks) formed therein is used as a raw material for extrusion molding, the density of the screw marks is lower than other parts. For this reason, it is fragile, which causes defects such as “cuts” and coarse “pores” in the molded body or the porous honeycomb filter as the final product. Therefore, the porous honeycomb filter as the final product may not perform the desired filtration performance.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is that the characteristics in each part of the obtained compressed product become uneven and the distribution thereof varies. An object of the present invention is to provide a screw for an extruder and a screw type extruder that can effectively prevent a situation in which discontinuous screw marks are formed inside a compressed product obtained.

  As a result of earnest research, in the screw for the extruder constituting the screw-type extruder, in addition to the spiral flight formed on the drive shaft, the propeller-like stirring blade is provided on the front end side of the drive shaft, thereby The present invention was completed by conceiving that the problem could be solved.

  According to the present invention, first, an extruder screw having a drive shaft and a spiral flight formed on the drive shaft, a plurality of blade portions are arranged in the axial direction of the drive shaft on the front end side of the drive shaft. There is provided an extruder screw provided with a propeller-like stirring blade arranged to be inclined with respect to the screw.

  In the extruder screw according to the present invention, although not limited, it is preferable that the propeller-like stirring blade is arranged at least 5% from the front end of the drive shaft.

  In the extruder screw according to the present invention, the shape of the blade portion constituting the propeller-shaped stirring blade is not limited. As the shape of the blade portion, for example, various shapes including a sector shape, a triangle shape, a quadrangle shape (rectangular shape, etc.) can be adopted. Further, a part of these shapes may be included in the drive shaft. A preferable shape of the blade portion is a fan shape, and it is particularly preferable that each of the plurality of blade portions has a fan shape.

  In addition, the number of blade portions constituting the propeller-shaped stirring blade is preferably 6 to 18, and more preferably 10 to 14, except for the number by division described later. preferable. If less than this range, apply a uniform shear force to the object to be processed by the propeller-like stirring blade, and it is not preferable in the point that the effect of kneading may not be obtained. Since the cross-sectional area of the flow path becomes too small, the extrusion resistance is increased, which is not preferable in that the thrust of extrusion cannot be maintained.

  Furthermore, although not limited, each of the plurality of blade portions may be further divided.

  In the extruder screw according to the present invention, it is preferable that a blank portion of 30 mm or more is provided between the propeller-shaped stirring blade and the spiral flight. More preferably, the blank portion is 50 to 150 mm. In addition, a blank part means the part in which neither a flight nor a blade | wing (part) is arrange | positioned in a drive shaft.

  When this blank part is absent or short, the workpiece is preferentially pushed out from the propeller-like stirring blades near the outlet of the spiral flight flow path, and the workpiece to be pushed out from the propeller-like stirring blades. The amount becomes uneven. By providing the blank portion, it serves as a reservoir for the object to be processed (soil) that has passed through the spiral flight, and the object to be processed is easily pushed out of the propeller-like stirring blades. When the blank portion is less than 30 mm, it is difficult to fulfill the function of storing the object to be processed (kneaded material), which is not preferable.

  Next, according to the present invention, an input port into which a workpiece containing powder is charged, a screw for an extruder according to any one of the above for compressing and feeding the charged workpiece, A hollow cylindrical body portion in which the extruder screw is accommodated, a driving means for rotationally driving the extruder screw, and a discharge port for discharging a compressed product of the object to be processed compressed by the extruder screw And a screw-type extruder having a lead-out portion that guides the compressed product to the discharge port, and a throttle portion having an inner diameter smaller than the shaft diameter on the front end side of the drive shaft of the screw for the extruder is formed in the lead-out portion. A screw extruder is provided. The shaft diameter on the front end side of the drive shaft of the extruder screw refers to the shaft diameter of the front end portion excluding the tapered portion that can be formed at the most front end of the drive shaft.

  According to the screw for an extruder of the present invention and the screw type extruder using the screw, the characteristics of each part of the obtained compressed product become non-uniform, and the distribution may vary, or the obtained compressed product It is possible to effectively prevent a situation in which a discontinuous screw mark is formed inside the.

  Conventionally, in a screw type extruder, the characteristics of each part of the obtained compressed product are non-uniform, and the distribution varies, or discontinuous parts (screw marks) are formed inside the obtained compressed product. The conventional screw type extruder 1 as shown in FIG. 6 has a spiral flight 7 of the screw 9 (i) because of its structure, the force is evenly applied to the workpiece. In addition to having a characteristic that (shearing force) cannot be applied, and (ii) a compressed product that is spirally laminated and compressed along the shape of the flight 7 is discharged. It has been found that there is a problem in that the spiral flight 7 is formed up to the most front end side of 9.

  Specifically, in the case of the conventional screw type extruder 1 as shown in FIG. 6, the object to be processed introduced into the body portion 3 from the inlet (not shown) is a spiral flight of the screw 9. In the portion 7, a shearing force is applied only in the vicinity of the edge and almost no shearing force is applied in the other portions, and it is impossible to apply the shearing force uniformly to the workpiece. It is presumed that the characteristics in each part of the above become non-uniform and the distribution varies.

  Further, in the screw type extruder 1, an object to be processed which is input from the input port (not shown) into the body portion 3 is a portion of the spiral flight 7 of the screw 9. It was inferred that discontinuous screw marks would be formed inside the resulting compressed product because it was discharged from the discharge port 11 as a compressed product that was spirally laminated and compressed along the shape.

  Therefore, the screw for an extruder according to the present invention does not form a spiral flight on the front end side of the drive shaft, but includes a propeller-like stirring blade disposed independently of the flight. By taking this mode, it is possible to apply a uniform shearing force to the object to be processed before being discharged from the discharge port. Therefore, the characteristics of each part of the obtained compressed product become non-uniform and the distribution thereof varies, or a discontinuous part (screw mark) is formed inside the obtained compressed product. Can be effectively prevented.

  Hereinafter, embodiments of a screw for an extruder according to the present invention and a screw type extruder using the same will be described in detail with reference to the drawings. A screw for an extruder according to the present invention and a screw type extruder using the screw according to the present invention are described below. However, the present invention is not limited to these embodiments. For example, the drawings show preferred embodiments of the present invention, but the present invention is not limited by the information shown in the drawings. In practicing or verifying the present invention, means similar to or equivalent to those described in the present specification can be applied, but preferred means are those described below.

(1) Screw for Extruder FIG. 1 is a cross-sectional view showing an embodiment of a screw for an extruder according to the present invention and a screw type extruder using the screw. A screw 29 of the screw-type extruder 21 shown in FIG. 1 has a drive shaft 5 and a spiral flight 7 formed on the drive shaft 5, and a propeller-like stirring is provided on the front end side of the drive shaft 5. A blade 6 is provided. The propeller-like agitating blade 6 is inclined with respect to the axial direction of the drive shaft 5 on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5, and 10 fan-shaped blade portions 4 are arranged. It has been made. Such a propeller-like stirring blade 6 can apply a uniform shearing force to the workpiece being extruded in the gap between the plurality of blade portions 4.

  The propeller-like agitating blade 6 needs to be disposed at least at a part from the front end of the drive shaft 5 and is not limited, but preferably the front end when the entire length of the drive shaft 5 is 100%. To 5% length. In the screw for an extruder according to the present invention, it is important to subdivide the object to be processed on the front end side, thereby eliminating various problems caused by the spiral stirring blade.

  The screw 29 shown in FIG. 1 is a continuous surface of the blade except for the front end side of the drive shaft 5 provided with the propeller-like stirring blade 6 as in the conventional screw for an extruder (see the screw 9 shown in FIG. 6). Is formed with a spiral flight 7 having one or more rounds around the drive shaft 5 and a plurality of fan-shaped flights 8 arranged intermittently. Such a flight is excellent in the effect of extruding the workpiece (extrusion effect).

  In the extruder screw according to the present invention, it is not preferable to provide a propeller-like stirring blade as a whole without providing a flight in a portion excluding the front end of the drive shaft. Although the propeller-shaped stirring blade applies a uniform shearing force to the object to be processed and is excellent in the kneading effect, the contact area between the metal and the object to be processed increases, so that the extrusion resistance increases. Therefore, it is preferable to arrange a propeller-like stirring blade on the front end side of the drive shaft and a spiral flight excellent in the effect of extruding the object to be processed (extrusion effect) on the rear end side.

  The arrangement method of the blade portion of the propeller-like stirring blade is not particularly limited as long as the blade portion is disposed to be inclined with respect to the axial direction of the drive shaft. Like the propeller-shaped stirring blade 6 shown in FIG. 1, each surface of the ten blade portions 4 is arranged so as to be inclined at a predetermined angle with respect to a plane perpendicular to the axial direction of the drive shaft 5. Preferably it is. Such an aspect of the blade portion has an advantage that the extrusion effect is excellent as compared with the case where each surface of the blade portion is disposed on a plane perpendicular to the axial direction of the drive shaft.

  FIG. 8 is a partially enlarged perspective view showing an embodiment of the screw for an extruder according to the present invention. The propeller-like stirring blade 86 of the screw 89 shown in FIG. 8 is formed up to the most front end side of the drive shaft 5 and is ten fan-shaped blades attached to the drive shaft 5 while being inclined with respect to the axial direction. The portion 84 is disposed on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5.

  3-5 is sectional drawing which shows other embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. The screw 39 of the screw extruder 31 shown in FIG. 3, the screw 49 of the screw extruder 41 shown in FIG. 4, and the screw 59 of the screw extruder 51 shown in FIG. 5 are shown in FIG. Similar to the screw 29 of the screw extruder 21, the drive shaft 5 and the spiral flight 7 formed on the drive shaft 5 are provided. Further, a propeller-like stirring blade is provided on the front end side of the drive shaft 5. Although provided, the aspect of the propeller-like stirring blade is different from that of the screw 29. The propeller-like stirring blade 36 of the screw 39 is inclined with respect to the axial direction of the drive shaft 5 on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5, and has four fan-shaped blade portions 34. The propeller-like stirring blade 46 of the screw 49 is further arranged so that each of the four blade portions 44 (similar to the propeller-like stirring blade 36) is a rectangular blade portion piece. The propeller-like stirring blade 56 of the screw 59 is further divided into three so that each of the four blade portions 54 (similar to the propeller-like stirring blade 36) becomes a fan-shaped blade portion piece. It has been divided. Comparing the propeller-like agitating blade 6 of the screw 29 and the propeller-like agitating blade 46 of the screw 49, the propeller-like agitating blade 6 is located on the outer periphery of the drive shaft 5 parallel to the plane perpendicular to the axial direction of the drive shaft 5. Whereas ten blade portions 4 are disposed, in the propeller-shaped stirring blade 46, four portions are disposed on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5. The blade portions 44 are divided into three parts and appear as a total of 12 blade portion pieces 47. The 12 blade portion pieces 47 thus divided are parallel to a plane perpendicular to the axial direction of the drive shaft 5. It is not arranged on the outer periphery of the drive shaft 5.

(2) Screw type extruder In the screw type extruder according to the present invention, the screw for compressing and feeding the input workpiece is the screw for the extruder according to the present invention described in the above (1). Is. Such a screw-type extruder can obtain the effect of kneading by applying a uniform shearing force to the workpiece in the vicinity of the discharge port of the extruder. Therefore, the characteristics of each part of the obtained compressed product become non-uniform and the distribution thereof varies, or a discontinuous part (screw mark) is formed inside the obtained compressed product. Can be effectively prevented.

  The screw type extruder of the present invention uses the screw for the extruder of the present invention described in the above (1) as the screw for compressing and feeding the workpiece to be processed, and driving the screw for the extruder at the outlet portion. Except for forming a throttle portion having an inner diameter smaller than the shaft diameter on the front end side of the shaft, it can be configured in the same manner as a conventionally known screw type extruder.

  Specifically, an input port into which an object to be processed containing powder is charged, a screw (for an extruder) for compressing and feeding the charged object to be processed, and a screw (for an extruder) are provided inside. A hollow cylindrical body to be disposed; drive means for rotationally driving a screw (for an extruder); a discharge port for discharging a compressed product of a workpiece compressed by the screw (for an extruder); and compression A lead-out portion for guiding the product to the discharge port, and it is sufficient that the lead-out portion has a throttle portion having an inner diameter smaller than the shaft diameter on the front end side of the drive shaft of the extruder screw. According to such a screw-type extruder, the object to be processed that has been input from the input port is compressed and sent out by the screw that is rotationally driven by the driving means inside the trunk portion, and as a high-density compressed product from the discharge port. Discharged.

  FIG. 2 is a cross-sectional view showing another embodiment of the screw for an extruder according to the present invention and a screw type extruder using the screw. A screw extruder 61 shown in FIG. 2 has a drive shaft 5 and a spiral flight 7 formed on the drive shaft 5 in the same manner as the screw extruder 21 shown in FIG. A screw 29 provided with a propeller-like stirring blade 6 on the front end side of the shaft 5 is used. In addition, a constriction portion having an inner diameter smaller than the shaft diameter on the front end side of the drive shaft 5 of the screw 29 is provided in the lead-out portion 12. 2 is formed. By forming such a narrowed portion 2, the processed material is subjected to a shearing force by passing through the narrowed portion 2 of the outlet portion 12 before being discharged from the discharge port 11. It is possible to make the characteristics in the portion more uniform and make it difficult to form discontinuous screw marks in the obtained compressed product.

  As for each component of the screw extruder, the shape, structure, material, etc. are not particularly limited as long as the function can be ensured, but an electric motor or the like is used as a driving means. Is common.

  Further, the screw type extruder according to the present invention further includes a vacuum chamber in which a vacuum pressure reducing device is connected between the charging port and the body portion for degassing the air contained in the object to be processed. It is preferable that With such a structure, a sufficiently deaerated object to be processed is supplied to the body portion, so that a compressed product with few defects, high density, and good moldability can be obtained. In addition, as a vacuum decompression device, a vacuum pump etc. can be used suitably, for example.

  The screw type extruder according to the present invention has an effect of applying a uniform shearing force to the object to be processed and kneading by arranging a propeller-like stirring blade on the front end side of the drive shaft. Effectively prevent a situation where the characteristics of each part of the compressed product become non-uniform and the distribution varies, or a discontinuous screw mark is formed inside the resulting compressed product. Is something you can do. However, when manufacturing raw materials for extrusion molding of high-performance ceramic products that require strict homogeneity of materials, a kneaded material previously kneaded by a non-screw type kneader having a high kneading effect is used as an object to be processed. More preferably, it is put into the screw type extruder according to the present invention. By doing so, it becomes possible to make the characteristics of each part of the obtained compressed product more uniform.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The average particle size of the aggregate particle raw materials in the following examples (including comparative examples) is detected by the X-ray transmission method using the Stokes liquid phase precipitation method as a measurement principle. The value of 50% particle diameter measured by a particle size distribution measuring device (for example, Cedigraph 5000-02 type manufactured by Shimadzu Corporation) was used.

  As aggregate material, talc (average particle size 20 μm) 41.6% by mass, kaolin (average particle size 10 μm) 10.1% by mass, alumina (average particle size 1 μm) 10.1% by mass, aluminum hydroxide (average A cordierite forming raw material was prepared by mixing at a ratio of 24.5% by mass (particle diameter 1 μm) and 13.7% by mass of silica (average particle diameter 20 μm).

  Then, 5 parts by mass of methylcellulose as an organic binder and 20 parts by mass of water as a dispersion medium were added to 100 parts by mass of the aggregate particle raw material. Further, a microcapsule (acrylic resin-based microcapsule) made of 30 parts by volume of foamed resin as a pore former was added to 100 parts by volume of the aggregate particle raw material to prepare an object to be processed.

  (Example 1) The above-mentioned object to be processed was subjected to a compression process using a screw type extruder 21 shown in FIG. The screw-type extruder 21 includes a propeller-shaped stirring blade 6 disposed on the front end side of the drive shaft, a spiral flight 7 continuously disposed so as to wind the surface of the drive shaft 5, and intermittently. A screw 29 having a plurality of fan-shaped flights 8 arranged was provided. As shown in FIG. 1, the front end side of the drive shaft 5 (the right side in the drawing) is 5% from the front end when the entire length of the drive shaft 5 is 100%. A propeller-shaped agitating blade 6 in which ten fan-shaped blade portions 4 are disposed so as to be inclined with respect to the axial direction of the drive shaft 5 is disposed. The blade portion 4 of the propeller-like stirring blade 6 was formed in a fan shape with a central angle of 20 °, and the blade height from the surface of the drive shaft 5 was 40 mm. As the arrangement method, ten blade portions 4 are arranged on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5, and the blade surfaces of the respective blade portions 4 are the axes of the drive shaft 5. It was arranged so as to be inclined by 16 ° with respect to a plane perpendicular to the direction.

  As shown in FIG. 1, a spiral flight 7 is arranged on the rear end side of the propeller-like stirring blade 6 (generally the central portion of the drive shaft in the drawing), and the continuous surface of the flight 7 has the drive shaft 5 attached thereto. The center has four rounds, and the spiral angle is inclined with respect to a plane perpendicular to the axial direction of the drive shaft 5 such that the blade surface is 16 °. In addition, the flight 7 was disposed in a length portion of 10 to 60% from the front end side of the drive shaft 5, and the blade height from the surface of the drive shaft 5 was 40 mm.

  As shown in FIG. 1, a plurality of fan-shaped flights 8 are intermittently arranged on the rear end side (left side in the drawing) of the spiral flight 7. The shape of the flight 8 was a sector having a central angle of 40 °, and the blade height from the surface of the drive shaft 5 was 40 mm. As the arrangement method, two flights 8 are arranged at the target position with the drive shaft 5 as the center, and the planes including the blade surfaces of the two flights 8 intersect (that is, the two flights 8 The blade surface is arranged so as to be inclined by 16 ° in the opposite direction with respect to a plane perpendicular to the axial direction of the drive shaft 5. The number (number) of flights 8 was four.

  The screw type extruder 21 according to the first embodiment includes an input port (not shown) into which an object to be processed including powder is input, a screw 29 for compressing and supplying the input object to be processed, and a screw 29. Are disposed inside, a hollow cylinder 3, drive means (not shown) for rotating and driving the screw 29, and a discharge port 11 through which a compressed material of the object compressed by the screw 29 is discharged. And a lead-out portion 22 that guides the compressed product to the discharge port 11. The body 3 has a cylindrical shape with an inner diameter of 200 mmφ and a length of 600 mm. And the derivation | leading-out part 22 is formed in the taper shape which becomes thin smoothly by the trunk | drum 3 side to the discharge port 11 which is 200 mm in diameter and 400 mm in length, and whose diameter is 145 mm. An electric motor was used as the driving means for the screw 29.

  Using such a screw-type extruder 21, a compression treatment was performed under the condition that the rotational speed of the drive shaft was 5 rpm, and a cylindrical compact (ceramic clay) having an outer diameter of 145 mmφ and a length of 500 mm was obtained. . The obtained compressed product was cut along a plane including the central axis, and the cut surface was observed. Moreover, the measurement sample was extract | collected from 15 places in order of one outer peripheral part-center part-other outer peripheral part of the compressed object, and the density was measured. The result is shown in FIG.

  (Example 2) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw extruder 61 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw-type extruder 61 is a screw-type extruder having specifications similar to the screw-type extruder 21 except that the specifications of the body portion 3 and the lead-out portion 12 are different. A mouth (not shown), a screw 29 for compressing and feeding the input workpiece, a hollow cylindrical body 3 in which the screw 29 is disposed, and a driving means for rotationally driving the screw 29 (Not shown), a discharge port 11 through which the compressed material of the object to be processed compressed by the screw 29 is discharged, and a lead-out portion 12 that guides the compressed material to the discharge port 11. The body 3 has a cylindrical shape with an inner diameter of 200 mmφ and a length of 600 mm. In the lead-out portion 12, the throttle portion 2 having an inner diameter of 50 mm is formed before reaching the discharge port 11 having an inner diameter of 200 mmφ, a length of 400 mm, and a diameter of 145 mmφ. An electric motor was used as the driving means for the screw 29.

  (Comparative Example 1) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw extruder 1 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw extruder 1 includes a screw 9 having a spiral flight 7 continuously arranged so as to wind the surface of the drive shaft 5 and a plurality of fan-shaped flights 8 intermittently arranged. It was provided. No propeller-like stirring blades are provided. A spiral flight 7 is arranged on the front end side (right side in the drawing) of the drive shaft 5, and the continuous surface of the blades of the flight 7 has five rounds around the drive shaft 5. The blade surface was inclined so as to be 16 ° with respect to a plane perpendicular to the axial direction. In addition, the flight 7 is disposed in a portion 60% from the front end of the drive shaft 5 and the height of the blade from the surface of the drive shaft 5 is 40 mm.

  On the rear end side (left side in the figure) of the spiral flight 7, a plurality of fan-shaped flights 8 are intermittently arranged as shown in FIG. The shape of the flight 8 was a sector having a central angle of 40 °, and the blade height from the surface of the drive shaft 5 was 40 mm. As the arrangement method, two flights 8 are arranged at the target position with the drive shaft 5 as the center, and the planes including the blade surfaces of the two flights 8 intersect (that is, the two flights 8 The blade surface is arranged so as to be inclined by 16 ° in the opposite direction with respect to a plane perpendicular to the axial direction of the drive shaft 5. The number (number) of flights 8 was four. The screw extruder 1 conforms to the screw extruder 21 of the first embodiment with respect to the specifications of the body portion 3 and the lead-out portion 22.

  (Comparative Example 2) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw extruder 31 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw extruder 31 includes a propeller-like stirring blade 36 disposed on the front end side of the drive shaft, a spiral flight 7 continuously disposed so as to wind the surface of the drive shaft 5, and intermittently. A screw 39 having a plurality of fan-shaped flights 8 arranged was provided. As shown in FIG. 3, the front end side of the drive shaft 5 (the right side in the drawing) is 5% from the front end when the entire length of the drive shaft 5 is 100%. A propeller-like stirring blade 36 in which four fan-shaped blade portions 34 are disposed so as to be inclined with respect to the axial direction of the drive shaft 5 is disposed. The blade part 34 of the propeller-shaped stirring blade 36 was formed in a fan shape with a central angle of 60 °, and the blade height from the surface of the drive shaft 5 was 40 mm. As an arrangement method thereof, four blade portions 34 are arranged on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5, and the blade surfaces of the respective blade portions 34 are the axes of the drive shaft 5. It was arranged so as to be inclined by 16 ° with respect to a plane perpendicular to the direction. In addition, the screw type extruder 31 is based on the screw type extruder 21 of Example 1 about the specification of the helical flight 7 and the fan-shaped flight 8, and the specification of the trunk | drum 3 and the derivation | leading-out part 22. FIG. .

  (Comparative Example 3) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw extruder 41 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw-type extruder 41 includes a propeller-like stirring blade 46 disposed on the front end side of the drive shaft, a spiral flight 7 continuously disposed so as to wind the surface of the drive shaft 5, and intermittently. A screw 49 having a plurality of fan-shaped flights 8 arranged was provided. Propeller-like agitating blades 46 are arranged on the most front end side (right side in the drawing) of the drive shaft 5 at a length of 5% from the front end when the entire length of the drive shaft 5 is 100%. As shown in FIG. 4, the propeller-like stirring blades 46 are arranged such that each of the four blade portions 44 is inclined with respect to the axial direction of the drive shaft 5, and each of the blade portions 44 has three blade portions. It is divided into pieces 47. The blade part piece 47 of the propeller-shaped stirring blade 46 has a rectangular shape, and the height of the blade from the surface of the drive shaft 5 is 40 mm. As an arrangement method thereof, on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5, blade portions 44 each composed of three blade portion pieces 47 are arranged, and each blade portion piece 47 is arranged. The blade surfaces are inclined by 16 ° with respect to a plane perpendicular to the axial direction of the drive shaft 5. In addition, the screw type extruder 41 is based on the screw type extruder 21 of Example 1 about the specification of the helical flight 7 and the fan-shaped flight 8, and the specification of the trunk | drum 3 and the derivation | leading-out part 22. FIG. .

  (Comparative Example 4) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw-type extruder 51 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw type extruder 51 includes a propeller-like stirring blade 56 disposed on the front end side of the drive shaft, a spiral flight 7 continuously disposed so as to wind the surface of the drive shaft 5, and intermittently. A screw 59 having a plurality of fan-shaped flights 8 arranged was provided. Propeller-like agitating blades 56 are arranged on the most front end side (right side in the drawing) of the drive shaft 5 at a length of 5% from the front end when the entire length of the drive shaft 5 is 100%. As shown in FIG. 5, the propeller-like stirring blade 56 is arranged such that each of the four blade portions 54 is inclined with respect to the axial direction of the drive shaft 5, and each of the blade portions 54 has three blade portions. It is divided into pieces 57. The blade piece 57 of the propeller-shaped stirring blade 56 has a fan shape with a central angle of 15 °, and the height of the blade from the surface of the drive shaft 5 is 40 mm. As an arrangement method thereof, blade portions 54 each including three blade portion pieces 57 are arranged on the outer periphery of the drive shaft 5 parallel to a plane perpendicular to the axial direction of the drive shaft 5. The blade surfaces are inclined by 16 ° with respect to a plane perpendicular to the axial direction of the drive shaft 5. In addition, the screw-type extruder 51 conforms to the screw-type extruder 21 of the first embodiment with respect to the specifications of the spiral flight 7 and the fan-shaped flight 8 and the specifications of the body portion 3 and the lead-out portion 22. .

  (Comparative Example 5) A compression product (ceramic clay) was obtained under the same conditions as in Example 1 except that the screw extruder 71 shown in FIG. The object is cut along the plane including its central axis, and the cut surface is observed, and measurement samples are collected from 15 locations in the order of one outer peripheral portion of the compressed product, the central portion, and the other outer peripheral portion, and the density is measured. did. The result is shown in FIG.

  The screw extruder 71 is a screw extruder having a specification similar to that of the conventional screw extruder 1 except that the specifications of the body portion 3 and the lead-out portion 12 are different. The screw extruder 71 winds the surface of the drive shaft 5. And a screw 9 having a spiral flight 7 continuously arranged and a plurality of fan-shaped flights 8 intermittently arranged. No propeller-like stirring blades are provided. A spiral flight 7 is arranged on the front end side (right side in the drawing) of the drive shaft 5, and the continuous surface of the blades of the flight 7 has five rounds around the drive shaft 5. The blade surface was inclined so as to be 16 ° with respect to a plane perpendicular to the axial direction. In addition, the flight 7 is disposed in a portion 60% from the front end of the drive shaft 5 and the height of the blade from the surface of the drive shaft 5 is 40 mm.

  On the rear end side (left side in the figure) of the spiral flight 7, a plurality of fan-shaped flights 8 are intermittently arranged as shown in FIG. The shape of the flight 8 was a sector having a central angle of 40 °, and the blade height from the surface of the drive shaft 5 was 40 mm. As the arrangement method, two flights 8 are arranged at the target position with the drive shaft 5 as the center, and the planes including the blade surfaces of the two flights 8 intersect (that is, the two flights 8 The blade surface is arranged so as to be inclined by 16 ° in the opposite direction with respect to a plane perpendicular to the axial direction of the drive shaft 5. The number (number) of flights 8 was four.

  The screw-type extruder 71 includes an inlet (not shown) into which a workpiece including powder is charged, a screw 9 for compressing and feeding the charged workpiece, and the screw 9 disposed therein. A hollow cylindrical body portion 3, driving means (not shown) for rotationally driving the screw 9, a discharge port 11 through which the compressed material of the object to be processed compressed by the screw 9 is discharged, and the compressed material The lead-out part 12 led to the discharge port 11 is provided. The body 3 has a cylindrical shape with an inner diameter of 200 mmφ and a length of 600 mm. In the lead-out portion 12, the throttle portion 2 having an inner diameter of 50 mm is formed before reaching the discharge port 11 having an inner diameter of 200 mmφ, a length of 400 mm, and a diameter of 145 mmφ. An electric motor was used as the driving means for the screw 9.

  (Consideration) As is clear from the graph shown in FIG. 9, the compressed material (ceramic clay) obtained by the screw type extruder of Comparative Example 1 has non-uniform density and uneven density distribution. there were. Therefore, when used as a raw material for extrusion molding in the production of a porous honeycomb filter, it is expected that the porosity of the finally obtained porous honeycomb filter will be non-uniform and the distribution will vary. It was done.

  Moreover, when the cut surface of the compressed material obtained in Comparative Example 1 was observed, it was recognized that a large number of screw marks were formed in a loose shape. Thus, the compressed product in which the screw marks were formed inside was weak in the screw mark portions and easily peeled off. Therefore, when used as a raw material for extrusion molding in the production of a porous honeycomb filter, defects such as “cuts” and coarse “pores” occur in the molded body or the final porous honeycomb filter. It was expected that the porous honeycomb filter, which is the final product, was easily damaged, and that the desired filtration performance was not achieved.

  On the other hand, in Example 1 and Example 2, the difference (Δρ) between the maximum density and the minimum density of the compressed product (ceramic clay) obtained by the screw extruder was improved as compared with Comparative Example 1. It has been confirmed that the density change from the central part to the outer peripheral part is small, the density is made more uniform, and the variation of the density distribution is reduced. It is constant. Therefore, even when used as a raw material for extrusion molding in the production of a porous honeycomb filter, it was expected that a porous honeycomb filter having a uniform porosity and less variation in its distribution could be obtained. In Comparative Examples 2 to 4, the difference (Δρ) between the maximum density and the minimum density is improved compared to Comparative Example 1, and the density is more uniform from the center to the outer periphery, but the effect is not good. It was enough. This was thought to be because the number of blade portions constituting the propeller-like stirring blade was small, and the effect of applying a uniform shearing force to the object to be processed and kneading was not sufficiently obtained.

  Moreover, when the cut surface of the compression thing obtained in Example 1 and Example 2 was observed, the screw trace was not recognized at all. Compressed material that does not have a fragile part such as a screw mark, even when it is used as a raw material for extrusion molding in the production of a porous honeycomb filter, It is expected that defects such as coarse “pores” rarely occur, and the porous honeycomb filter as the final product is not easily damaged or does not fail to achieve the desired filtration performance.

  According to the screw for an extruder of the present invention and the screw type extruder using the screw, the characteristics of each part of the obtained compressed product become non-uniform, and the distribution may vary, or the obtained compressed product It is possible to effectively prevent a situation in which a discontinuous screw mark is formed inside the. Therefore, production of ceramic clay using a mixture of ceramic powder, dispersion medium, binder, etc. as an object to be processed, especially production of raw materials for extrusion molding for producing porous honeycomb filters such as diesel particulate filters (DPF). Is preferably used.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows one Embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. It is sectional drawing which shows other embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. It is sectional drawing which shows other embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. It is sectional drawing which shows other embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. It is sectional drawing which shows other embodiment of the screw for extruders which concerns on this invention, and a screw-type extruder using the same. It is sectional drawing which shows an example of the conventional screw type extruder. It is sectional drawing which shows the other example of the conventional screw type extruder. It is a partial expansion perspective view which shows one Embodiment of the screw for extruders which concerns on this invention. It is a graph which shows distribution of density (rho) in each part of the ceramic clay obtained with the screw type extruder in the Example.

Explanation of symbols

1, 21, 31, 41, 51, 61, 71 ... screw type extruder, 3 ... barrel part, 4, 34, 44, 54, 84 ... blade part, 5 ... drive shaft, 6, 36, 46, 56, 86 ... propeller-like stirring blades, 7, 8 ... flight, 9, 29, 39, 49, 59, 89 ... screw, 11 ... discharge port, 12, 22 ... lead-out part, 47, 57 ... blade part piece.

Claims (5)

A screw for an extruder having a drive shaft and a spiral flight formed on the drive shaft,
The front end of the drive shaft, Ri propeller stirring blade tilting the plurality of vane portions with respect to the axial direction of the drive shaft formed by arranged the Sonawa,
The screw for an extruder , wherein the number of the plurality of blade portions is 6 to 18 .   The screw for an extruder according to claim 1, wherein the propeller-like stirring blade is disposed at a length portion of at least 5% from a front end of the drive shaft.   The screw for an extruder according to claim 1 or 2, wherein each of the plurality of blade portions has a fan shape. The screw for an extruder according to any one of claims 1 to 3 , wherein a blank portion of 30 mm or more is provided between the propeller-shaped stirring blade and the spiral flight. 5. An extruder port according to any one of claims 1 to 4 for compressing and feeding the input workpiece to be processed, and an inlet into which the workpiece to be processed containing powder is charged, and the extrusion A hollow cylindrical body portion in which the machine screw is housed, drive means for rotationally driving the extruder screw, and a compressed product of the object to be processed compressed by the extruder screw are discharged. A screw type extruder provided with a discharge port and a lead-out portion for guiding the compressed product to the discharge port,
A screw type extruder in which a narrowed portion having an inner diameter smaller than the shaft diameter on the front end side of the drive shaft of the extruder screw is formed in the lead-out portion.

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