Processing equipment for powders and granules

Abstract

To provide a particulate matter processing device which can process particulate matters with excellent energy efficiency without causing stirring blades and collision plates to contact with each other during the processing.SOLUTION: A particulate matter processing device 10 is used to perform processing for causing particulate matters to be processed to collide and includes: a vertical mixing tank 20; a rotary shaft 30 which is provided inserted into a tank bottom of the mixing tank; a plurality of stirring blades 40 provided at the rotary shaft; a plurality of collision plates 50 which are disposed above the stirring blades so as to be spaced apart from upper ends of the stirring blades; and a refrigerant flow passage 70 for circulating a cooling medium in an inner space of the mixing tank. The collision plates are fixed to a wall surface of the refrigerant flow passage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a powder or granular material processing apparatus for performing a process of causing powder or granular materials to be processed to collide with each other. [Background Art]

[0002] Compounding and spheroidizing of powder or granular materials are performed by a process of applying compressive force and shearing force through collision to micron-order or nano-order powder or granular materials. By applying compressive force and shearing force to particles through collision, the particles can be pulverized to reduce the aspect ratio, and corner portions can be removed to obtain rounded particles. In addition, aggregated particles can be disintegrated and finely dispersed.

[0003] At the same time, particles can be bonded to each other by applying compressive force and shearing force through collision. In particular, when compressive force and shearing force are applied by collision in a state where large particles and small particles are mixed, the surface of the large particles becomes covered with the small particles and the particles are integrated. Hereinafter, the description will be given by referring to large particles as "mother particles" and small particles as "child particles".

[0004] Untreated particles and aggregated particles often have spaces between particles, a low bulk density and a large specific surface area. In contrast, particles integrated by collision often have child particles driven into the surface of the mother particle, or the child particles are often integrated with each other without gaps, so they become particles with a high bulk density and a small specific surface area.

[0005] By integrating mother particles and child particles, spheroidization treatment of the particles is generally performed. When the types of the mother particles and the child particles are different, this process can be referred to as particle compounding treatment. It is not uncommon to perform compounding treatment using two or more types of child particles.

[0006] By covering the surface of a mother particle with child particles, the surface properties of the composite particle acquire the properties of the child particles, and this process is sometimes referred to as surface modification. If the mother particle is a soft material such as resin, the child particles can be fixed in a state where they are completely embedded within the mother particle. On the other hand, if the mother particle is a hard material and the child particles are made of a material that is easily deformed, the child particles may become integrated with each other, a state sometimes referred to as encapsulation.

[0007] Here, Patent Document 1 describes a processing apparatus for compounding and shaping powders and granules. The processing apparatus disclosed in Patent Document 1 comprises a vertical mixing tank, a rotating shaft inserted through the bottom of the mixing tank, a plurality of stirring blades provided on the rotating shaft, and a plurality of impact plates fixed to the mixing tank. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Patent No. 5575139 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, the energy efficiency of the process changes depending on the relative positions of the stirring blades and the impact plate, so it is desirable to set them to the optimal positional relationship. On the other hand, it is essential to avoid situations in which the stirring blades and the impact plate come into contact during the process.

[0010] Therefore, the present invention aims to provide a processing apparatus for powders and granules that can process powders and granules with excellent energy efficiency without bringing the stirring blades and impact plates into contact during processing. [Means for solving the problem]

[0011] To achieve the above objective, the present invention provides a granular material processing apparatus for processing granular materials to be processed by impacting them, comprising: a vertical mixing tank; a rotating shaft inserted through the bottom of the mixing tank; a plurality of stirring blades provided on the rotating shaft; a plurality of impact plates positioned above such that there is a gap between them and the upper ends of the stirring blades; and a refrigerant flow passage for circulating a cooling medium through the interior of the mixing tank, wherein the impact plates are fixed to the wall surface of the refrigerant flow passage. [Effects of the Invention]

[0012] In the powder and granular material processing apparatus of the present invention configured in this way, since the impact plate is fixed to the wall surface of the refrigerant flow passage, even if the temperature of the powder and granular material becomes high due to the high-speed rotation of the stirring blades during processing, the temperature rise is suppressed and displacement due to thermal expansion is also suppressed.

[0013] Therefore, the stirring blades and the impact plate do not come into contact during processing, and the relative positions of the stirring blades and the impact plate, which are set to maximize energy efficiency, enable the processing of powders and granules. [Brief explanation of the drawing]

[0014] [Figure 1] This is a longitudinal cross-sectional view showing the schematic configuration of the processing apparatus according to an embodiment of the present invention. [Figure 2] This figure shows an example of a cooling system for a processing apparatus according to an embodiment of the present invention, where (a) is a schematic plan view and (b) is a schematic longitudinal cross-sectional view. [Figure 3] This diagram illustrates the general configuration of the refrigerant flow path, where (a) is a longitudinal cross-sectional view of the inlet of the cooling medium, (b) is a longitudinal cross-sectional view of the outlet of the cooling medium, and (c) is a longitudinal cross-sectional view of the moving part. [Figure 4] This figure shows an example of a refrigerant flow path and a collision plate, where (a) is a schematic longitudinal section view and (b) is a cross-sectional view taken in the direction of arrow AA in (a). [Figure 5] This is an explanatory diagram showing the relationship between the stirring blades and the impact plate. [[Mode for Carrying Out the Invention]]

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a longitudinal cross-sectional view showing a schematic configuration of a processing apparatus 10 according to an embodiment of the present invention.

[0016] The processing apparatus 10 according to an embodiment of the present invention is a powder / granule processing apparatus capable of performing advanced processing such as particle compounding and spheroidization by performing processing of causing the powder / granule to be processed to collide with each other. Specifically, it is a processing apparatus that performs processing of applying compressive force and shearing force to powder / granules through collision. For example, the processing apparatus 10 can perform spheroidization processing of particles in which child particles are collided with and fixed to the surface of mother particles, compounding processing in which different types of particles are collided with and fixed to each other, and the like.

[0017] The processing apparatus 10 according to an embodiment of the present invention includes a vertical mixing tank 20, a rotating shaft 30 provided to penetrate through the tank bottom of the mixing tank 20, a plurality of stirring blades 40 provided on the rotating shaft 30, a plurality of impact plates 50 arranged above with a gap formed between the upper end portions 45 (see Fig. 5) of the stirring blades 40 and the impact plates 50, and a refrigerant flow passage 70 for circulating a cooling medium in the inner space of the mixing tank 20.

[0018] The mixing tank 20 is a cylindrical container formed centered on a vertical axis. Generally, a cylindrical container having a horizontal axis is referred to as "horizontal", and a cylindrical container having a vertical axis is referred to as "vertical".

[0019] The mixing tank 20 is provided with an openable / closable lid 60 at an upper portion thereof to enable maintenance and inspection of the inner space. The mixing tank 20 can be sealed or opened by the flange 21 of the mixing tank 20 and the flange 61 of the lid 60. A flange 80 and a gasket 25 of a cooling system, which will be described in detail later, are mounted between the flange 21 and the flange 61.

[0020] In the processing apparatus 10, batch processing is performed instead of continuous processing. For this purpose, the lid 60 is provided with a powder and granular material inlet 62, through which powder and granular material serving as a raw material is charged. In addition, an inspection port, a viewing window, an exhaust port and the like are appropriately provided on the lid 60.

[0021] Preferably, the mixing tank 20 is provided with a jacket covering its outer peripheral surface to heat or cool the processed material. It is also preferable that the mixing tank is provided with a thermometer capable of measuring the temperature of the processed material.

[0022] A discharge port 22 is provided at a corner near the tank bottom of the mixing tank 20, through which the processed powder and granular material is discharged. A discharge valve is provided at the discharge port 22. When the discharge valve is closed, the tip end of the valve body is formed to have the same shape as the inner wall surface of the mixing tank 20, so that it does not affect the processing of the powder and granular material. When discharging the powder and granular material, by opening the discharge valve while rotating the stirring blade 40 slowly, the powder and granular material can be discharged reliably.

[0023] The mixing tank 20 is mounted on a frame 90 together with an unshown electric motor, and is configured such that power from the electric motor is transmitted to the rotating shaft 30 via a transmission device such as a V-belt provided under the frame 90. It is preferable that the rotation speed of the rotating shaft 30 is variable and can be freely set.

[0024] The rotating shaft 30 is sealed against the mixing tank 20 by an unshown gland seal, air seal or the like. When gas is used, it is preferable to provide a filter on the lid 60 to collect powder entrained in exhaust gas discharged from the mixing tank 20.

[0025] The stirring blades 40 are arranged and formed on the inclined surface of a boss portion 41 formed in a substantially conical shape. The boss portion 41 is attached to the rotating shaft 30, and is formed such that the bottom surface of the boss portion 41 is close to the tank bottom of the mixing tank 20.

[0026] Preferably, each of the multiple stirring blades 40 is connected by a ring-shaped upper plate 42. In this case, the powder flows between each stirring blade 40, passing under the ring-shaped upper plate 42, thus achieving a stable flow state.

[0027] Furthermore, the processing apparatus 10 of this embodiment is characterized in that a refrigerant flow passage 70 through which a cooling medium flows is provided inside the mixing tank 20, and an impact plate 50 is fixed to the wall surface of this refrigerant flow passage 70.

[0028] The function of this configuration will be explained in detail later, but the cooling system centered on the refrigerant flow passage 70 suppresses displacement of the impact plate 50 due to thermal expansion, and the relative positional relationship between the stirring blade 40 and the impact plate 50 can be accurately maintained even during processing.

[0029] In the embodiment shown in Figure 1, the refrigerant flow passage 70 is positioned near the stirring blade 40, and the impact plates 50 are fixed to the wall surface of the refrigerant flow passage 70. The cooling medium is configured to flow from the refrigerant flow passage 70 into the interior of each impact plate 50.

[0030] Figure 1 shows the internal structure of the mixing tank 20, illustrating the relative positional relationship between the cooling system and the stirring blades 40, etc. However, since the cooling system is formed as a single unit, it can be shown separately as in Figure 2. Cooling water is typically used as the cooling medium.

[0031] This cooling system is equipped with a flange 80 on top to secure the entire system to the mixing tank 20. The flange 80 is fixed in place, sandwiched between the flange 21 of the mixing tank 20 and the flange 61 of the lid 60.

[0032] Cooling medium inlets 81, 83 and outlets 82, 84 are fixed to the upper part of the flange 80. The lid 60 is provided with openings 63 as appropriate, allowing the inlets 81 and other components to be positioned outside the mixing tank 20.

[0033] Inlets 81 and 83 are connected to the refrigerant flow passage 70 by inlet pipes 85 and 87, respectively, and outlets 82 and 84 are connected to the refrigerant flow passage 70 by outlet pipes 86 and 88, respectively.

[0034] Figure 3 is a diagram illustrating the schematic configuration of the refrigerant flow passage 70. Figure 3(a) shows the part where the inlet pipe 85 (87) is connected to the refrigerant flow passage 70. The inside of the refrigerant flow passage 70 is divided into upper and lower sections, with the lower section being the inlet passage 71 for the cooling medium and the upper section being the outlet passage 72 for the cooling medium.

[0035] The inlet pipe 85(87) is connected to the cooling medium inlet passage 71 formed on the lower side. Meanwhile, Figure 3(b) shows the part where the outlet pipe 86(88) is connected to the refrigerant flow passage 70. The outlet pipe 86(88) is connected to the cooling medium outlet passage 72. Furthermore, as shown in Figure 3(c), an opening 73 is provided in the partition between the inlet passage 71 and the outlet passage 72 to move the cooling medium from the inlet passage 71 to the outlet passage 72.

[0036] In the processing apparatus 10 of this embodiment, the flange 80 and the refrigerant flow passage 70 are connected by inlet pipes 85, 87 and outlet pipes 86, 88. Therefore, as long as the powder and granular material are being processed while the cooling medium is flowing, the possibility of the refrigerant flow passage 70 moving downward due to thermal expansion is very small.

[0037] In other words, even if the impact plate 50 is simply fixed to the wall surface of the refrigerant flow passage 70, thermal expansion and downward movement of the impact plate 50 can be suppressed. Furthermore, as shown in Figure 4, by forming flow holes (51, 52) for the cooling medium inside the impact plate 50, thermal expansion and downward movement of the impact plate 50 can be prevented more reliably.

[0038] Here, Figure 4(a) shows a schematic longitudinal cross-sectional view of the refrigerant flow passage 70 in the portion where the impact plate 50 is attached. Figure 4(b) is a cross-sectional view taken in the direction of arrow AA in Figure 4(a).

[0039] The inlet passage 71 of the refrigerant flow passage 70 communicates with the inlet hole 51 of the impact plate 50, and the outlet passage 72 of the refrigerant flow passage 70 communicates with the outlet hole 52 of the impact plate 50. Therefore, the cooling medium that flows from the inlet pipes 85 and 87 into the inlet passage 71 of the refrigerant flow passage 70 flows through the inlet hole 51 and outlet hole 52 of each impact plate 50, and then returns to the outlet passage 72 of the refrigerant flow passage 70, from where it flows out into the outlet pipes 86 and 88.

[0040] The circulation of the cooling medium by the cooling system within the mixing tank 20 ensures a uniform flow of the cooling medium to each impact plate 50, allowing each impact plate 50 to maintain a more stable state against thermal expansion.

[0041] Next, the operation of the processing apparatus 10 of this embodiment will be described. The processing apparatus 10 of this embodiment, configured in this way, is equipped with a cooling system that includes a cooling medium supply line and a cooling medium discharge line, so that the cooling medium can be reliably circulated inside the impact plate 50. That is, by connecting the cooling medium supply line to the inlets 81 and 83 formed in the flange 80 and the cooling medium discharge line to the outlets 82 and 84, the cooling medium can be circulated in the refrigerant flow passage 70 and the impact plate 50.

[0042] Here, we will explain in detail the effects of the cooling system in which the impact plate 50, a feature of the processing apparatus 10 of this embodiment, is fixed to the wall surface of the refrigerant flow passage 70.

[0043] First, a new finding was obtained that a shorter minimum distance between the stirring blade 40 and the impact plate 50 is preferable. In other words, it was found that the narrower the gap between the stirring blade 40 and the impact plate 50, the higher the energy efficiency and the more desirable processing can be performed. Specifically, it was found that a gap of 5 mm or less between the stirring blade 40 and the impact plate 50 is preferable, and even narrower, between 1 mm and 3 mm, is preferable. The progress of the processing of the powder and granular material was confirmed by the changes in the bulk density and specific surface area of ​​the processed material.

[0044] However, the narrower the gap between the stirring blade 40 and the impact plate 50, the higher the risk of contact between the two. In particular, since the high-speed rotating stirring blade 40 raises the temperature of the powder to over 100°C, it is conceivable that the thermal expansion of the impact plate 50 and the internal structure supporting the impact plate 50 may cause the gap to narrow by about 1 to 2 mm compared to its initial state.

[0045] Therefore, in order to avoid contact between the stirring blades 40 and the impact plate 50, a refrigerant flow passage 70 through which the cooling medium flows is provided inside the mixing tank 20, and the impact plate 50 is fixed to the wall surface of this refrigerant flow passage 70.

[0046] By structuring the processing apparatus 10 in this way, the temperature change of the refrigerant flow passage 70 and the impact plate 50 can be kept to about 50°C before and after the start of processing, and the displacement of the gap can be kept to less than 1 mm. Therefore, if the gap between the stirring blade 40 and the impact plate 50 can be accurately adjusted within the range of 1 mm to 3 mm before the start of processing, a safe processing operation can be performed without the stirring blade 40 and the impact plate 50 coming into contact.

[0047] The preferred structure of the stirring blade 40 and the impact plate 50 will be described below with reference to Figure 5. In Figures 1-4 above, the impact surface of the impact plate 50 was shown as vertical for the sake of illustration. However, as shown in detail in Figure 5, there is a preferred range for the mounting angle θ of the impact plate 50. Here, the mounting angle θ refers to the angle between the rotation direction of the stirring blade 40, indicated by the arrow in Figure 5, and the impact surface of the impact plate 50.

[0048] The powdered material to be processed flows in the direction of rotation of the stirring blades 40 in the mixing tank 20, and is also subjected to an outward centrifugal force from the axis of the mixing tank 20, causing it to flow upward from the corners of the tank bottom along the tank walls.

[0049] The mounting angle θ of the impact plate 50 is selected to impart strong compressive and shearing forces to the powder and granules, while ensuring favorable circulation and flow of the powder and granules within the tank. For powder and granules with good fluidity, an angle of approximately 45° to 75° is preferred, while for powder and granules with poor fluidity, an angle of approximately 60° to 90° is preferred. The preferred tip speed of the stirring blade 40 is 50 m / s to 100 m / s.

[0050] Furthermore, it is preferable that the stirring blades 40 and the impact plates 50 have parallel edges where they are close to each other, and more preferably, the direction in which they are parallel is horizontal. That is, it is preferable that the upper end portion 45 of each stirring blade 40 is located on the same horizontal plane as the upper surface of the ring-shaped upper plate 42. It is also preferable that the edge that becomes the lower end portion 55 of each impact plate 50 is located slightly above the upper end portion 45 and extends horizontally.

[0051] As shown in Figure 5, the gap C between the horizontal plane where the upper end 45 of the stirring blade 40 is located and the horizontal plane where the lower end 55 of the impact plate 50 is located is the shortest distance between the stirring blade 40 and the impact plate 50.

[0052] This structure allows the lower end 55 of the impact plate 50 to be positioned on top of the upper end 45 of the stirring blade 40 when the gap C is brought close to 0 mm. As shown in Figures 1 and 2, the impact plate 50 is fixed to the mixing tank 20 via a flange 80 together with the refrigerant flow passage 70.

[0053] Therefore, by adjusting the thickness of the gasket 25 adjacent to the flange 80 of the cooling system, the gap C can be adjusted. In short, the processing apparatus 10 can be assembled with high precision regarding the gap C.

[0054] For example, suppose that when the cooling system is initially placed in the mixing tank 20 without using the gasket 25, the lower end 55 of the impact plate 50 is placed on top of the upper end 45 of the stirring blade 40. In this state, the gap between flange 80 and flange 21 is measured and the distance is determined. This gap is denoted as distance C1 (not shown).

[0055] To ensure that the final assembled gap is gap C (see Figure 5), the thickness of the gasket 25 should be (C1 + C). The thickness of the gasket 25 can be easily adjusted using a shim (gap gauge). Therefore, it is easy to precisely adjust the shortest distance between the stirring blade 40 and the impact plate 50 within a range of 1 mm to 3 mm.

[0056] While embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

[0057] For example, although the above embodiment described an impact plate 50 equipped with flow holes (51, 52), it is not limited to this, and an impact plate 50 without flow holes for the cooling medium may also be used. As described above, even just fixing it to the wall surface of the refrigerant flow passage 70 can suppress thermal expansion and downward movement of the impact plate.

[0058] Furthermore, the cross-sectional structure of the refrigerant flow passage 70, the shape and quantity of the stirring blades 40 and the impact plates 50 are not limited to those described in the above embodiment, and can be freely selected to suit the application and scale of the processing device. [Explanation of Symbols]

[0059] 10: Processing unit 20: Mixing tank 30: Rotation axis 40: Agitation blade 41: Boss Department 42: Ring-shaped top plate 45: Upper end 50: Collision plate 51:Inflow hole (flow hole) 52:Outflow hole (flow hole) 55: Bottom end 70: Refrigerant flow path C: Gap

Claims

1. A processing apparatus for granular materials that performs a process of impacting granular materials to be processed, A vertical mixing tank, A rotating shaft is provided, inserted through the bottom of the mixing tank, Multiple stirring blades are provided on the aforementioned rotating shaft, Multiple impact plates are positioned above the upper end of the stirring blade so as to create a gap between them and the upper end of the stirring blade, The mixing tank is equipped with a refrigerant flow passage for circulating a cooling medium within its interior, The upper end of the stirring blade and the lower end of the impact plate are both extended horizontally, and the shortest distance of the gap between the stirring blade and the impact plate can be adjusted within a range of 1 mm to 3 mm. The interior of the refrigerant flow passage is divided into a lower inflow passage for the cooling medium and an upper outflow passage for the cooling medium. A processing apparatus for powders and granules, characterized in that the cooling medium flows from the inlet passage into a flow hole formed inside the impact plate fixed to the wall surface of the refrigerant flow passage and is returned to the outlet passage.

2. The powder processing apparatus according to claim 1, characterized in that the stirring blades are arranged on the inclined surface of a boss portion formed in a substantially conical shape, and the upper parts of the stirring blades are connected by a ring-shaped upper plate.

Images