Granulation device

Abstract

To provide a granulator excellent in wear resistance.SOLUTION: A granulator A includes a granulation tank 40 having a cylindrical drum 41, and a disc 60 arranged so as to block an opening on a bottom surface of the drum 41, and a drive mechanism 20 that drives the disc 60 coaxially with the drum 41, wherein a granulation material G is charged into the granulation tank 40 and the disc 60 is rotated to produce a granulation product. Among an inner peripheral surface of the drum 41 and the upper surface of the disc 60, in a region where the granulation material G comes into contacts with as a rotation of the disc 60, a dish-shaped urethane lining 66 is provided.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a granulator.

Background Art

[0002] Patent Document 1 discloses a granulator having a centrifugal rolling part in which a rotating pan is surrounded by a cylindrical fixed wall. When powder particles, powder, and a binder are put into the centrifugal rolling part and the rotating pan is rotated, the powder particles are coated with the powder, and a granulated product is produced.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the granulator described in Patent Document 1, the rotating pan and the fixed wall are made of metal. Therefore, when the powder particles are made of a hard material such as ceramic, there has been a risk that the rotating pan and the fixed wall may wear out at an early stage.

[0005] The invention of the present application has been completed based on the above circumstances, and an object thereof is to improve the wear resistance of a granulation tank.

Means for Solving the Problem

[0006] The present invention provides: a granulation tank having a cylindrical drum and a disk arranged to close an opening in a bottom surface of the drum; and a drive mechanism that rotationally drives the disk coaxially with the drum, the granulator producing a granulated product by putting a granulation material into the granulation tank and rotating the disk, A urethane lining is provided in the area between the inner surface of the drum and the upper surface of the disk, where the granulated material comes into contact as the disk rotates. [Effects of the Invention]

[0007] According to the present invention, even when the granulation material is a hard material such as metal, wear between the drum and the disc can be suppressed. Therefore, the wear resistance of the granulation tank can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Cross-sectional view of the granulation apparatus in Example 1 [Figure 2] Plan view of the granulation tank [Figure 3] Enlarged cross-sectional view showing the fixing structure between the underplate and the cylindrical member. [Figure 4] Enlarged cross-sectional view showing the fixing structure of the underplate and ring-shaped member. [Figure 5] Enlarged cross-sectional view showing the structure of the slit. [Figure 6] Cross-sectional view of the granulation apparatus in Example 2 [Figure 7] Plan view of the granulation tank in Example 2 [Figure 8] Cross-sectional view of the granulation apparatus in Example 3 [Figure 9] Plan view of the granulation tank in Example 3 [Modes for carrying out the invention]

[0009] First, embodiments of this disclosure will be listed and described. Any combination of the following embodiments, in a manner that does not create a contradiction, is also included as a form for carrying out the invention.

[0010] The present invention (1) A granulation apparatus comprising a granulation tank having a cylindrical drum and a disc positioned to close the opening at the bottom of the drum, and a drive mechanism for rotating the disc coaxially with the drum, wherein a granulation material is introduced into the granulation tank and the disc is rotated to produce a granulated product. A urethane lining is provided in the area between the inner circumferential surface of the drum and the upper surface of the disc that comes into contact with the granulation material as the disc rotates. The urethane resin, which is the material of the urethane lining, is resistant to wear even when relatively hard materials come into contact with it, thus improving the wear resistance of the granulation tank.

[0011] (2) In (1), a slit is formed between the outer peripheral edge of the disc and the inner peripheral surface of the drum, and it is preferable that at least one of the inner opposing surface of the outer peripheral edge of the disc that constitutes the slit and the outer opposing surface of the inner peripheral surface of the drum that constitutes the slit is formed of a urethane slit lining. This configuration suppresses wear within the slit and, consequently, suppresses the fall of granulated material from the slit.

[0012] (3)(2) The drum is preferably configured to include a cylindrical member that does not include the outer opposing surface and a ring-shaped member that includes the outer opposing surface, wherein the ring-shaped member is detachable from the cylindrical member. With this configuration, when the slit lining forming the outer opposing surface wears out, only the ring-shaped member needs to be replaced, and the entire drum does not need to be replaced.

[0013] (4) In (1) to (3), it is preferable that the urethane lining provided on the upper surface of the disc has a rotation-promoting surface in which a plurality of flat portions are connected at an obtuse angle. With this configuration, the transmission of rotational force from the disc to the granulation material is promoted by the rotation-promoting surface, so that good granulation can be achieved.

[0014] In (5) and (4), it is preferable that the disc comprises a disc main body made of a plate material and the urethane lining covering an upper surface of the disc main body, and the rotation promotion surface is formed by partially changing a thickness of the urethane lining. According to this configuration, the shape of the disc main body can be simplified.

[0015] In (6) and (1) to (3), it is preferable that the urethane lining provided on an inner peripheral surface of the drum has a flow promotion surface formed by connecting a plurality of flat planes in an obtuse angle shape. According to this configuration, the flow of the granulation material is promoted by the flow promotion surface, so favorable granulation can be achieved.

[0016] In (7) and (1) to (3), it is preferable that the drum is rotatable in both forward and reverse directions. According to this configuration, favorable granulation can be performed by adjusting the relative rotation direction of the drum with respect to the disc and the relative rotation speed of the drum with respect to the disc.

[0017] <Example 1> Hereinafter, Example 1 embodying the present invention will be described with reference to Figs. 1 to 5. In the following description, regarding the up-down direction, the directions shown in Figs. 1 and 3 to 5 are directly defined as upper and lower. The up-down direction and the axial direction are used synonymously. A direction orthogonal to the up-down direction (axial direction) is defined as a radial direction.

[0018] The granulation apparatus A of Example 1 is an apparatus for producing granulated products such as foods and pharmaceuticals such as ramune and tablets, chemical products such as detergents and deodorants, grinding stones for barrel polishing, and ceramic balls for catalyst carriers. As granulation methods, there are a coating granulation method of coating the surface of core pellets (granulation material G) with powder and granular material (granulation material G), and a method of aggregating and enlarging wet powder and granular material, etc. The granulation apparatus A of Example 1 can be used as a coating apparatus.

[0019] As shown in Figure 1, the granulation apparatus A comprises a base plate 10, a housing 11, a drive mechanism 20, an underplate 26, and a granulation tank 40. The base plate 10 is horizontally positioned on a base (not shown). The housing 11 is box-shaped with an open bottom and is mounted on the base plate 10 so as to cover the granulation tank 40 from above. An inlet 12 and a dust collection port 13 are open on the top of the housing 11. The granulation material G, consisting of core balls and powder, is fed into the granulation tank 40 through the inlet 12. A water supply pipe 14 is inserted through the inlet 12. A nozzle 15 for spraying water onto the granulation material G in the granulation tank 40 is provided at the lower end of the water supply pipe 14. A duct for a dust collection device (not shown) is connected to the dust collection port 13.

[0020] The drive mechanism 20 comprises a first motor 21, a rotating shaft 22, a second motor 24, and a spur gear 25. The first motor 21 is positioned below the base plate 10 and fixed to a base (not shown). The rotating shaft 22 is a cylindrical component with its axis oriented vertically and open at both the upper and lower ends. The rotating shaft 22 is rotatably supported relative to the base plate 10, passing through the central hole of the base plate 10. The rotating shaft 22 is rotationally driven in both forward and reverse directions by the first motor 21. The interior of the rotating shaft 22 functions as an air intake hole 23 that passes through the rotating shaft 22 vertically. An air supply source (not shown) is connected to the lower end of the air intake hole 23.

[0021] The second motor 24 is mounted on the underside of the base plate 10. A spur gear 25 with its axis oriented vertically is attached to the upward-facing drive shaft of the second motor 24. In a top view of the granulator A, the spur gear 25 is positioned eccentrically with respect to the rotation axis 22. The spur gear 25 is positioned above the base plate 10.

[0022] The underplate 26 has a circular shape in plan view and a concave dish shape on its upper surface. The underplate 26 is a single component having a circular plate body 27 and a cylindrical peripheral wall 28 that rises concentrically from the outer edge of the plate body 27. The underplate 26 is a single component made of a metal material such as stainless steel. The underplate 26 is supported on the upper surface of the base plate 10 in a state in which its axis is oriented vertically and it can rotate concentrically with the rotation axis 22. An internal gear 29 is provided concentrically with the underplate 26 on the lower surface of the outer edge of the underplate 26. The internal gear 29 is meshed with a spur gear 25 of the second motor 24. The underplate 26 is rotationally driven by the second motor 24 in both forward and reverse directions, and its peripheral speed can be adjusted.

[0023] As shown in Figures 3 and 4, a flange-shaped support portion 30 is formed on the upper edge of the peripheral wall portion 28, extending radially outward concentrically with the underplate 26. The support portion 30 has a horizontal mounting portion 31 that forms an annular shape and a circular wall-like portion 32 that rises upward concentrically from the outer peripheral edge of the mounting portion 31. Multiple first mounting holes 33 are formed at spaced intervals in the circumferential direction of the mounting portion 31, penetrating the mounting portion 31 in the vertical direction (see Figure 3). Between adjacent first mounting holes 33 in the circumferential direction of the mounting portion 31, a second mounting hole 34 is formed, penetrating the mounting portion 31 in the vertical direction (see Figure 4). Multiple adjustment female screw holes 35 are formed at spaced intervals in the circumferential direction of the wall-like portion 32, penetrating the wall-like portion 32 in the radial direction (horizontal direction). An adjustment bolt 36 is screwed into the adjustment female screw hole 35 from the outer peripheral surface side.

[0024] As shown in Figure 1, the granulation tank 40 is composed of a cylindrical drum 41 and a disc 60 positioned to close the opening at the bottom of the drum 41. The inside of the granulation tank 40 functions as a granulation space for granulation. The drum 41 is composed of a cylindrical tubular member 42 with its axis oriented vertically, and an annular ring-shaped member 50 with its axis oriented vertically. The tubular member 42 is an integrated unit of the drum body 43 and a cylindrical urethane lining 44. The drum body 43 is a single cylindrical part made of metal such as stainless steel. Multiple fixing first female screw holes 45 are formed at the lower end of the drum body 43, spaced apart in the circumferential direction (see Figure 3). The fixing first female screw holes 45 have their axes oriented vertically and open to the lower end surface of the drum body 43.

[0025] The cylindrical urethane lining 44 is formed by insert molding and adheres tightly to the entire inner surface of the drum body 43. In the insert molding process, the inner surface of the drum body 43 is roughened by blasting or other methods to improve the adhesion between the drum body 43 and the cylindrical urethane lining 44.

[0026] As shown in Figures 1 and 2, the inner surface of the upper end region of the cylindrical urethane lining 44 is composed of multiple rectangular planes 46 connected in the circumferential direction. As shown in Figure 2, the plan view shape of the inner surface of the upper end region of the cylindrical urethane lining 44 is a regular polygon (regular dodecagon). The inner surface of the lower end region of the cylindrical urethane lining 44 functions as a flow-promoting surface 47. The flow-promoting surface 47 is composed of multiple isosceles triangular planes 48 with their vertices pointing upward and multiple isosceles triangular planes 48 with their vertices pointing downward, connected alternately in the circumferential direction at obtuse angles. The flow-promoting surface 47 is a surface formed by adjusting the radial thickness dimension of the cylindrical urethane lining 44. The inner circumferential edge of the lower end of the cylindrical urethane lining 44 is circular.

[0027] The ring-shaped member 50 is formed by integrating a ring body 51 and a ring-shaped urethane lining 52. The ring body 51 is a single annular component made of a metal such as stainless steel. The ring body 51 has a plurality of adjustment through holes 53 that are spaced apart in the circumferential direction (see Figure 3). The adjustment through holes 53 have their axes oriented vertically and penetrate the ring body 51. The ring body 51 has a plurality of fixing second female screw holes 54 that have their axes oriented vertically and penetrate the ring body 51 (see Figure 4). The plurality of fixing second female screw holes 54 are arranged between adjacent adjustment through holes 53 in the circumferential direction.

[0028] The ring-shaped urethane lining 52 is formed by insert molding and adheres tightly to the entire inner surface of the ring body 51. As shown in Figure 5, the inner diameter of the upper end region of the ring body 51 is constant from the upper end to the lower end. The inner surface of the lower end region of the ring body 51 has a tapered shape (frustoconical shape) where the inner diameter gradually increases from the upper end to the lower end. In the insert molding process, the inner surface of the ring body 51 is roughened by blasting or other methods to improve the adhesion between the ring body 51 and the ring-shaped urethane lining 52.

[0029] The inner circumferential surface of the ring-shaped urethane lining 52 has a circular shape in plan view. The ring-shaped urethane lining functions as a slit lining that constitutes the slit 73, which will be described later. The inner diameter of the upper end region of the ring-shaped urethane lining is constant throughout the entire region from the lower end to the upper end. The upper end region of the inner circumferential surface of the ring-shaped urethane lining 52, where the inner diameter is constant, functions as the outer opposing surface 55 facing the slit 73. A wide area of ​​the inner circumferential surface of the ring-shaped urethane lining 52 below the upper end has a tapered shape (frustoconical shape) such that the inner diameter gradually increases from the upper end to the lower end.

[0030] The drum 41 is fixed to the support portion 30 of the underplate 26 so as to be able to rotate integrally with it. When fixing the drum 41, the ring-shaped member 50 is placed on the upper surface of the mounting portion 31, and the adjustment through hole 53 is aligned concentrically with the first mounting hole 33, and the fixing second female screw hole 54 is aligned concentrically with the second mounting hole 34. Next, the cylindrical member 42 is placed on the upper surface of the ring-shaped member 50, and the fixing first female screw hole 45 is aligned concentrically with the adjustment through hole 53. Then, from below the mounting portion 31, the first bolt 56 is passed through the first mounting hole 33 and the adjustment through hole 53 and screwed into the fixing second female screw hole 54. Similarly, from below the mounting portion 31, the second bolt 57 is passed through the second mounting hole 34 and screwed into the fixing second female screw hole 54. The underplate 26, the ring-shaped member 50, and the cylindrical member 42 are fixed together by the first bolt 56 and the second bolt 57. By tightening the first bolt 56 and the second bolt 57, the cylindrical member 42 and the ring-shaped member 50 are integrated and fixed to the underplate 26.

[0031] The disc 60 is a shallow, dish-shaped component with a concave top surface. The disc 60 is an integrated unit of a disc body 61 and a dish-shaped urethane lining 66. The disc body 61 is a component made of metal such as stainless steel. The disc body 61 is a single component having a circular horizontal plate portion 62 and a tapered plate portion 63 that is concentric with the horizontal plate portion 62 and has a frustoconical shape. The tapered plate portion 63 has a shape that extends diagonally upward from the outer peripheral edge of the horizontal plate portion 62 so as to gradually become higher radially outward (towards the outer peripheral edge).

[0032] The central hole of the horizontal plate portion 62 (disk body 61) is fixed so that it can rotate integrally with the upper end of the rotation shaft 22. There is a ventilation gap between the upper surface of the plate body portion 27 and the lower surface of the disk body 61. The disk body 61 has multiple ventilation holes 64 that penetrate from the lower surface to the upper surface of the horizontal plate portion 62. A circular dome-shaped cover 65 that covers the opening at the upper end of the air supply hole 23 and all the ventilation holes 64 is attached concentrically to the upper surface of the horizontal plate portion 62 and the disk body 61.

[0033] The dish-shaped urethane lining 66 is formed by insert molding and adheres closely to the upper surface of the disc body 61. In the insert molding process, the upper surface of the disc body 61 is roughened by blasting or other methods to improve adhesion between the disc body 61 and the dish-shaped urethane lining 66. The dish-shaped urethane lining 66 is formed on the upper surface of the disc body 61 in the entire area on the outer periphery of the cover 65. Specifically, the dish-shaped urethane lining 66 is formed on the annular region on the outer edge of the horizontal plate portion 62 and on the entire tapered plate portion 63.

[0034] As shown in Figures 1 and 2, a rotation-promoting surface 67 is formed on the upper surface of the dish-shaped urethane lining 66. As shown in Figure 2, the rotation-promoting surface 67 is composed of multiple irregularly shaped planes 68 consisting of an arc and three straight lines, and multiple triangular planes 69. The multiple irregularly shaped planes 68 and the multiple triangular planes 69 are arranged alternately in the circumferential direction and are connected at obtuse angles. The rotation-promoting surface 67 is a surface formed by adjusting the thickness of the dish-shaped urethane lining 66 while keeping the thickness of the disc body 61 constant.

[0035] As shown in Figure 5, the outermost edge 63E of the tapered plate portion 63 of the disc body 61 has an upwardly pointed shape. The outer edge of the dish-shaped urethane lining 66 has a downwardly folded portion 70 that is in close contact with the outer surface of the outermost edge 63E. The folded portion 70 functions as a slit lining that constitutes the slit 73. The outer surface of the folded portion 70 (slit lining) functions as an inner opposing surface 71 facing the slit 73.

[0036] A slit 73, which has a circular shape in plan view, is formed between the inner circumferential surface of the lower end of the drum 41 and the outer circumferential edge of the disc 60. The slit 73 is composed of the inner circumferential surface (outer opposing surface 55) of the ring-shaped urethane lining 52 and the folded portion 70 (inner opposing surface 71) of the dish-shaped urethane lining 66. The slit 73 is a space that penetrates in the vertical direction and connects the internal space of the granulation tank 40 with the ventilation space 59 secured between the lower surface of the disc 60 and the upper surface of the underplate 26.

[0037] In a cross-section of the granulator A cut to include the rotation center of the rotation axis 22, the outer opposing surface 55 and the inner opposing surface 71 are parallel to each other. The radial gap of the slit 73 (the distance between the outer opposing surface 55 and the inner opposing surface 71) is set to approximately 0.2 to 0.4 mm, which is assumed to be difficult for the powder material (granulation material G) to pass through. In order to make the gap of the slit 73 uniform around its entire circumference, the horizontal position of the ring-shaped member 50 is adjusted so that the ring-shaped member 50 is positioned concentrically with respect to the underplate 26. During adjustment, with the first bolt 56 and the second bolt 57 loosened, the ring-shaped member 50 is moved horizontally by pressing the multiple adjustment bolts 36 against the outer circumferential surface of the ring-shaped member 50 (ring body 51). With the ring-shaped member 50 positioned, the first bolt 56 and the second bolt 57 are tightened to fix the ring-shaped member 50 to the underplate 26.

[0038] Next, the operation of this embodiment 1 will be explained. First, core balls of the granulation material G are put into the granulation tank 40, and water or the like is sprayed from the nozzle 15 to wet the surface of the core balls. During this time, the disc 60 and drum 41 are rotated to make the core balls flow. When the powder material is supplied into the granulation tank 40 while the core balls are flowing, the powder material adheres to the wet surface of the core balls in a snowball-like manner. By repeating the spraying of water from the nozzle 15 and the supply of powder material, the granulated product grows. During granulation, some of the powder material put into the granulation tank 40 is blown up, but the blown-up powder material is sucked up by the dust collector from the dust collection port 13.

[0039] As the granulated product grows, the rotational force of the disc 60 is easily transmitted to the core ball and granules by the rotation-promoting surface 67 of the disc 60. As a result, the core ball and granules tend to rise high along the inner surface of the drum 41 from the outer edge of the disc 60 due to centrifugal force, creating an avalanche-like flow. At the same time, the flow-promoting surface 47 of the drum 41 prevents the core ball and granules from flowing laterally in the circumferential direction, thus promoting vertical flow. This vertical flow helps to evenly coat the granules, improving the degree of growth. In particular, when the drum 41 is rotated in the opposite direction to the disc 60, adhesion of the granules to the drum 41 can also be suppressed.

[0040] When the granulating material G contains granular material harder than stainless steel (for example, alumina), if this hard granular material comes into contact with the stainless steel drum body 43 or disc body 61 while flowing at high speed, the contact area of ​​the granular material may wear down. In particular, wear is significant near the slit 73, i.e., in the outer peripheral region of the disc 60 and the lower end of the drum 41, where the centrifugal force acting on the granular material due to the rotational force of the disc 60 is maximum. To counter this, in this embodiment 1, the inner circumferential surface of the drum body 43 is covered with a cylindrical urethane lining 44, and the upper surface of the disc body 61 is covered with a dish-shaped urethane lining 66. Urethane resin is resistant to wear even when granular material harder than stainless steel comes into contact with it at high speed.

[0041] Granulation experiments were conducted using granulation apparatus A of this embodiment 1 under the following conditions. The capacity of the granulation tank 40 was 40 liters, the outer diameter of the disc 60 was 400 mm, the maximum diameter of the circle circumscribing the inner surface of the regular dodecagon of the drum 41 was 460 mm, the spacing of the slits 73 was 0.2 mm, the rotation speed of the disc 60 was 350 rpm in the forward direction, and the rotation speed of the drum 41 was 20 rpm in the reverse direction. 2 kg of core balls with an outer diameter of 0.15 mm were placed into the granulation tank 40, and spherical barrel abrasive stones with an outer diameter of 0.3 mm were granulated. The powder consisted of a mixture of clay components and alumina abrasive grains #400 (average particle size 37 μm). By repeatedly supplying this powder and water from the nozzle 15, 16 kg of spherical abrasive stones (granulated product) with an outer diameter of 0.3 mm were produced. In this experiment, since urethane linings 44 and 66 were applied to the inner surface of the drum 41 and the upper surface of the disc 60, the drum body 43 and the disc body 61 did not wear down.

[0042] By providing a slit 73 between the inner circumferential surface of the drum 41 and the outer edge of the disc 60, the drum 41 and the disc 60 can rotate without contact. This prevents sliding resistance from occurring between the drum 41 and the disc 60, and ensures smooth rotation of the drum 41 and the disc 60. The outer opposing surface 55 and the inner opposing surface 71 that constitute the slit 73 have a gap (0.2 mm to 0.4 mm) that prevents powder from falling through. In addition, air supplied to the air supply hole 23 of the rotating shaft 22 is pumped into the granulation tank 40 through the slit 73, passing sequentially through the space inside the cover 65, the ventilation hole 64, and the ventilation space 59. Therefore, even if powder with a diameter smaller than the width of the slit 73 is supplied into the granulation tank 40, there is no risk of that small-diameter powder falling through the slit 73 into the ventilation space 59.

[0043] Even if some of the powder gets caught in the slit 73, the outer opposing surface 55 and the inner opposing surface 71 that make up the slit 73 are made of urethane resin, so there is no risk of them being worn down by the caught powder. In the unlikely event that powder gets caught in the slit 73 and the outer opposing surface 55 is worn down, the ring-shaped member 50 having the outer opposing surface 55 can be replaced. When replacing the ring-shaped member 50, the first bolt 56 and the second bolt 57 are removed, and the cylindrical member 42 and the ring-shaped member 50 are removed from the support portion 30 of the underplate 26. Then, the new ring-shaped member 50 is placed on the underplate 26, the cylindrical member 42 is positioned on top of it, and the cylindrical member 42 and the ring-shaped member 50 are fixed together with the first bolt 56 and the second bolt 57.

[0044] The granulation apparatus A of this embodiment 1 comprises a granulation tank 40 and a drive mechanism 20. The granulation tank 40 has a cylindrical drum 41 and a disc 60 positioned to close the opening at the bottom of the drum 41. The drive mechanism 20 rotates the disc 60 coaxially with the drum 41. Granulated products are manufactured by introducing granulation material G (core balls and powder) into the granulation tank 40 and rotating the disc 60. A cylindrical urethane lining 44 and a dish-shaped urethane lining 66 are provided on the inner circumferential surface of the drum 41 and the upper surface of the disc 60. The cylindrical urethane lining 44 and the dish-shaped urethane lining 66 are positioned in the areas where the granulation material G comes into contact with the disc 60 as it rotates. The urethane resin material of the cylindrical urethane lining 44 and the dish-shaped urethane lining 66 is resistant to wear even when relatively hard materials come into contact with it. Therefore, according to the granulation apparatus A of this embodiment 1, the wear resistance of the granulation tank 40 can be improved, so even when the granulation material G is a hard material such as metal, wear of the drum 41 and disc 60 can be suppressed.

[0045] A slit 73 is formed between the outer edge of the disc 60 and the inner surface of the drum 41. The slit 73 connects the space inside the granulation tank 40 with the ventilation space 59 outside the granulation tank 40. However, since air is pumped from the ventilation space 59 into the granulation tank 40, there is no risk of the powder or granular material inside the granulation tank 40 falling into the ventilation space 59. The inner opposing surface 71 of the outer edge of the disc 60 that constitutes the slit 73 and the outer opposing surface 55 of the inner surface of the drum 41 that constitutes the slit 73 are formed by a urethane slit lining (folded portion 70 and ring-shaped urethane lining 52). With this configuration, wear inside the slit 73 can be suppressed, and thus the falling of the granulation material G (powder or granular material) from the slit 73 can be suppressed.

[0046] The drum 41 is composed of a cylindrical member 42 that does not include the outer opposing surface 55, and a ring-shaped member 50 that includes the outer opposing surface 55. The ring-shaped member 50 is detachable from the cylindrical member 42. When the slit lining (ring-shaped urethane lining 52) that forms the outer opposing surface 55 wears out, only the ring-shaped member 50 needs to be replaced. Therefore, the entire drum 41 does not need to be replaced.

[0047] The cylindrical urethane lining 44 provided on the inner circumferential surface of the drum 41 has a flow-promoting surface 47 formed by arranging multiple planes (isosceles triangular planes 48) in the circumferential direction at an obtuse angle. Since the flow of the granulation material G (core balls and powder particles) is promoted by the flow-promoting surface 47, good granulation can be achieved. The flow-promoting surface 47 is formed by partially changing the thickness of the cylindrical urethane lining 44 while keeping the plate thickness of the drum body 43 constant, so the shape of the drum body 43 can be simplified.

[0048] The dish-shaped urethane lining 66 provided on the upper surface of the disc 60 has a rotation-promoting surface 67. The rotation-promoting surface 67 has a configuration in which a plurality of irregularly shaped planes 68 and a plurality of triangular planes 69 are arranged alternately in the circumferential direction and connected at obtuse angles. The transmission of rotational force from the disc 60 to the granulation material G is promoted by the rotation-promoting surface 67, so good granulation can be achieved. The disc 60 is composed of a disc body 61 made of a metal plate and a dish-shaped urethane lining 66 that covers the upper surface of the disc body 61. The irregularly shaped planes 68 and triangular planes 69 that constitute the rotation-promoting surface 67 are formed by partially changing the thickness of the dish-shaped urethane lining 66 while keeping the plate thickness of the disc body 61 constant, so the shape of the disc body 61 can be simplified.

[0049] The drum 41 is rotatable in both forward and reverse directions. By adjusting the relative rotation direction of the drum 41 with respect to the disc 60, and the relative rotation speed of the drum 41 with respect to the disc 60, good granulation can be achieved.

[0050] <Example 2> Next, Embodiment 2, which embodies the present invention, will be described with reference to Figures 6 and 7. The granulation apparatus B of Embodiment 2 is a modified version of the granulation apparatus A of Embodiment 1, in which the drum 81 and disc 83 constituting the granulation tank 80 are changed. Specifically, the shape of the inner circumferential surface of the cylindrical urethane lining 82 of the drum 81 and the shape of the upper surface of the dish-shaped urethane lining 84 of the disc 83 are changed. The other components are the same as those of Embodiment 1, so the same components are denoted by the same reference numerals, and the explanation of the structure, operation and effect is omitted.

[0051] In a top-down plan view of granulation apparatus B, the upper end region of the inner surface of the cylindrical urethane lining 82 is circular. The lower end region of the inner surface of the cylindrical urethane lining 82 is a frustoconical shape, with the inner diameter gradually decreasing downwards. The inner surface of the cylindrical urethane lining 82 does not have the flow-promoting surface 47 described in Example 1. The upper surface of the dish-shaped urethane lining 84 of the disc 83 is a frustoconical shape, sloping upwards towards the outer circumference. The dish-shaped urethane lining 84 does not have the rotation-promoting surface 67 described in Example 1.

[0052] Granulation experiments were conducted using granulation apparatus B of this Example 2 under the following conditions. The capacity of the granulation tank 80 was 40 liters, the outer diameter of the disc 83 was 400 mm, the maximum diameter of the inner circumference of the drum 81 was 460 mm, the slit spacing was 0.2 mm, the rotation speed of the disc 83 was 220 rpm in the forward direction, and the rotation speed of the drum 81 was 20 rpm in the reverse direction. 4 kg of core balls with an outer diameter of 0.5 mm were placed into the granulation tank 80, and spherical barrel abrasive stones with an outer diameter of 0.8 mm were granulated. The powder consisted of a mixture of clay components and alumina abrasive grains #100 (average particle size 150 μm). By repeatedly supplying this powder and water from the nozzle, 16 kg of spherical abrasive stones with an outer diameter of 0.8 mm were produced. In this experiment, since urethane linings 82 and 84 were applied to the inner surface of the drum 81 and the upper surface of the disc 83, neither the drum 81 nor the disc 83 body wore down.

[0053] In the granulation apparatus B of Example 2, the disc 83 does not have a rotation-promoting surface 67, and the drum 81 does not have a flow-promoting surface 47. However, when the alumina abrasive particle size of the granulated barrel polishing stone is large, this size creates resistance to the drum 81 and disc 83, resulting in good flow in the rotational direction. Furthermore, if the granular material contains large alumina abrasive particles, vertical entrainment flow occurs. Therefore, good granulation can be achieved.

[0054] <Example 3> Next, Embodiment 3, which embodies the present invention, will be described with reference to Figures 8 and 9. The granulation apparatus C of Embodiment 3 is the same as that of the granulation apparatus A of Embodiment 1, but with the shape of the upper surface of the dish-shaped urethane lining 84 of the disc 83 being the same as that of Embodiment 2. That is, the rotation-promoting surface 67 is not formed on the upper surface of the dish-shaped urethane lining 84. The other components are the same as those of Embodiment 1, so the same components are denoted by the same reference numerals, and the explanation of the structure, operation and effect is omitted.

[0055] In the granulation apparatus C of Example 3, the disc 83 does not have a rotation-promoting surface 67 formed thereon. However, when the granulated material has a large diameter, such as alumina used in barrel polishing, this size creates resistance to the disc 83, allowing the rotational force of the disc 83 to be effectively transmitted to the granulated material. As the particle size and weight of the granulated material increase, the centrifugal force acting on the granulated material due to the rotation of the disc 83 also increases, making it easier for the granulated material to rise along the inner surface of the drum 41. The powder and granular material also rise along the inner surface of the drum 41 together with the granulated material. The flow-promoting surface 47 of the drum 41 creates vertical entrainment flow of the granulated material and powder and granular material, enabling effective granulation.

[0056] <Other examples> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention. In Examples 1 to 3, the urethane lining on the disc may be provided only on a portion of the disc (only on the outer edge region). In Examples 1 to 3, the urethane lining on the drum may be provided only on a portion of the drum (only on the lower end side). In Examples 1 to 3, the slitting lining may be formed on only one of the inner opposing surfaces of the disc and the outer opposing surface of the drum. In Examples 1 to 3, the thickness of the urethane lining may be kept constant throughout the entire area, and the upper surface of the disc body may be formed to have the same shape as the rotation-promoting surface. In Examples 1 to 3, the drum may be fixed in place without rotating. In Example 1, the drum may be configured without a flow-promoting surface. In Example 2, the inner diameter of the cylindrical urethane lining of the drum may be constant over the entire length from the bottom end to the top end of the drum. [Explanation of symbols]

[0057] A...Pelletizer B…Pelletizer C…Pelletizer G...Granulation material 20…Drive mechanism 40...Granulation tank 41…Drums 42...Cylindrical member 44...Tubular urethane lining (urethane lining) 47…Flow-promoting surface 48…Isosceles triangular plane (the plane that constitutes the flow-promoting surface) 50... Ring-shaped member 52…Ring-shaped urethane lining (urethane lining, lining for slits) 55…Outer opposing surface 60…Disk 61…Disc body 66…Dish-shaped urethane lining (urethane lining) 67... Rotation-promoting surface 68... Irregularly shaped plane (a plane that constitutes a rotation-promoting surface) 69…Triangular plane (the plane that constitutes the rotation-promoting surface) 70...Folded-over section (lining for slits) 71...Inner opposing surface 73... Slit 80…Granulation tank 81... Drums 82...Tubular urethane lining 83…Disk 84…Dish-shaped urethane lining

Claims

1. A granulation tank having a cylindrical drum and a disc positioned to close the opening at the bottom of the drum, The system comprises a drive mechanism that rotates the disk coaxially with the drum, A granulation apparatus for producing granulated products by introducing granulation material into the granulation tank and rotating the disk, A urethane lining is provided in the area between the inner circumferential surface of the drum and the upper surface of the disk, where the granulated material comes into contact as the disk rotates. A slit is formed between the outer edge of the disk and the inner surface of the drum. The inner opposing surface of the outer peripheral edge of the disk that constitutes the slit and the outer opposing surface of the inner peripheral surface of the drum that constitutes the slit are parallel to each other. The distance between the inner opposing surface and the outer opposing surface is set to 0.2 mm to 0.4 mm. A granulation apparatus in which air is pumped into the granulation tank through the slit.

2. The granulation apparatus according to claim 1, wherein at least one of the inner opposing surface and the outer opposing surface is formed by a urethane slitting lining.

3. The drum is configured to include a cylindrical member that does not include the outer opposing surface and a ring-shaped member that includes the outer opposing surface. The granulation apparatus according to claim 2, wherein the ring-shaped member is detachable from the cylindrical member.

4. The granulation apparatus according to any one of claims 1 to 3, wherein the urethane lining provided on the upper surface of the disc has a rotation-promoting surface in which a plurality of flat portions are connected at an obtuse angle.

5. The aforementioned disc comprises a disc body made of a plate material and a urethane lining that covers the upper surface of the disc body. The granulation apparatus according to claim 4, wherein the rotation-promoting surface is formed by partially changing the thickness of the urethane lining.

6. The granulation apparatus according to any one of claims 1 to 3, wherein the urethane lining provided on the inner circumferential surface of the drum has a flow-promoting surface in which a plurality of planes are connected at an obtuse angle.

7. The granulation apparatus according to any one of claims 1 to 3, wherein the drum is rotatable in both forward and reverse directions.

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