Mixing device and method for manufacturing mixture

Abstract

A mixing device according to one embodiment of the present invention is provided with a conveyance unit for conveying a powder, a powder molding mechanism for molding the powder into a layered shape, and a liquid spraying mechanism for spraying a liquid onto the powder molded into the layered shape, and the powder molding mechanism is provided with a first blade and a second blade for molding the powder in the height direction with respect to the conveyance unit. The height of the scraper relative to the conveying part changes in the conveying process of the powder conveyed by the conveying part.

Description

Technical Field

[0001] The present invention relates to a mixing device for mixing a powder and a liquid, and a method for manufacturing a mixture using the mixing device. Background Art

[0002] Patent Document 1 discloses a manufacturing apparatus for a clad solder sheet having a rolling mill that rolls a metal plate and raw material powder having a solder composition. The apparatus has a liquid supply device that supplies a liquid to the raw material powder to be rolled by the rolling mill to adjust the adhesion between the particles constituting the raw material powder. The liquid supply device has a spray nozzle that supplies a liquid to the raw material powder conveyed by a belt feeder.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-95871 Summary of the Invention

[0006] A mixing device according to one aspect of the present invention includes: a conveying unit that conveys a powder; a powder forming mechanism that forms the powder into a layer; and a liquid spraying mechanism that sprays a liquid onto the powder formed into a layer. The powder forming mechanism has a doctor blade that forms the powder in a height direction relative to the conveying unit, and during the conveyance of the powder by the conveying unit, the height of the doctor blade continuously changes relative to the conveying unit.

[0007] In addition, a method for manufacturing a mixture according to one aspect of the present invention uses a mixing device, where the mixing device includes: a conveying unit that conveys a powder; a powder forming mechanism that forms the powder into a layer; and a liquid spraying mechanism that sprays a liquid onto the powder formed into a layer. The powder forming mechanism has one or more doctor blades that form the powder in a height direction relative to the conveying unit, and during the conveyance of the powder by the conveying unit, the height of the doctor blade changes between a first height and a second height higher than the first height. The method for manufacturing a mixture includes: a conveying step of conveying the powder using the conveying unit; a powder forming step of forming the powder being conveyed in the conveying step into a layer using the powder forming mechanism; and a liquid spraying step of spraying a liquid onto the powder formed into a layer in the powder forming step using the liquid spraying mechanism. Brief Description of the Drawings

[0008] Figure 1 It is a perspective view showing the structure of the mixing device according to Embodiment 1.

[0009] Figure 2It is a top view showing the structure of the mixing device of Embodiment 1.

[0010] Figure 3 It is a Figure 2 cross-sectional view taken along line III-III in

[0011] Figure 4 It is a Figure 2 cross-sectional view taken along line IV-IV in

[0012] Figure 5 It is a side view of the cover of the liquid spraying mechanism

[0013] Figure 6 It is a flowchart showing an example of a method for manufacturing a mixture using the mixing device of Embodiment 1.

[0014] Figure 7 It is a perspective view showing the structure of the mixing device of Embodiment 2.

[0015] Figure 8 It is a cross-sectional view showing the structure of the powder molding mechanism of the mixing device of Embodiment 2.

[0016] Figure 9 It is a top view showing the structure of the moving mechanism and its periphery of the mixing device of Embodiment 2. Detailed Embodiment

[0017] [Embodiment 1]

[0018] Hereinafter, an embodiment of the present invention will be described in detail. In the following description, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less".

[0019] Figure 1 It is a perspective view showing the structure of the mixing device 1 of Embodiment 1. Figure 2 It is a top view showing the structure of the mixing device 1. As Figure 1 and Figure 2 shown, the mixing device 1 may include a conveying unit 10, a powder molding mechanism 20, a liquid spraying mechanism 30, a moving mechanism 40, a control unit 50, and a storage unit 60. In Figure 2 the control unit 50 and the storage unit 60 are omitted.

[0020] The conveying unit 10 may be configured to be able to convey the powder 90. For convenience, the powder 90 is omitted in Figure 1 . The powder 90 is, for example, particles such as ceramics. Specific examples of the powder 90 include alumina powder, zirconia powder, and graphite powder.

[0021] The conveying unit 10 may include a first conveying unit 11 and a second conveying unit 12. The first conveying unit 11 and the second conveying unit 12 may be, for example, belt conveyors having an annular belt and pulleys for rotating the belt. The conveying direction of the powder 90 by the first conveying unit 11 and the conveying direction of the powder 90 by the second conveying unit 12 may be the same or different from each other. In particular, when the conveying direction of the powder 90 by the first conveying unit 11 and the conveying direction of the powder 90 by the second conveying unit 12 are the same, it is possible to reduce the deviation of the thickness of the powder 90 in the direction along the conveying surface of the powder 90 by the conveying unit 10 and in the direction perpendicular to the conveying direction when the powder 90 moves from the first conveying unit 11 to the second conveying unit 12.

[0022] In the following description, the conveying direction of the powder 90 by the first conveying unit 11 and the conveying direction of the powder 90 by the second conveying unit 12 may sometimes be referred to as the conveying direction of the powder 90 by the conveying unit 10, or simply as the conveying direction. In addition, the direction along the conveying surface of the powder 90 by the conveying unit 10 and the direction perpendicular to the conveying direction may sometimes be referred to as the width direction.

[0023] The first conveying unit 11 has an upstream end 11a and a downstream end 11b in the conveying direction, and a conveying surface 11c for conveying the powder 90 between the upstream end 11a and the downstream end 11b. The powder forming mechanism 20 is located on the conveying surface 11c. The second conveying unit 12 has an upstream end 12a and a downstream end 12b in the conveying direction, and a conveying surface 12c for conveying the powder 90 between the upstream end 12a and the downstream end 12b. In the conveying direction, the liquid spraying mechanism 30 and the moving mechanism 40 are located on the conveying surface 12c in this order. The area between the upstream end 12a of the second conveying unit 12 and the liquid spraying mechanism 30 is located below the downstream end 11b of the first conveying unit 11.

[0024] In the mixing device 1, the powder 90 is supplied into the powder forming mechanism 20 located in the first conveying unit 11. The powder 90 is formed by the powder forming mechanism 20 and is conveyed from the powder forming mechanism 20 to the downstream end 11b of the first conveying unit 11. The powder 90 falls from the downstream end 11b of the first conveying unit 11. The second conveying unit 12 conveys the powder that has fallen from the first conveying unit 11. The powder 90 is sprayed with liquid by the liquid spraying mechanism 30 during the conveyance by the second conveying unit 12.

[0025] In the mixing device 1, by allowing the powder 90 to fall from the first conveying unit 11 to the second conveying unit 12, it is possible to reduce the unevenness formed on the surface of the powder 90 during the forming process performed by the powder forming mechanism 20. Therefore, it is possible to reduce the deviation in the ratio between the powder 90 and the liquid sprayed by the liquid spraying mechanism 30 due to the unevenness formed on the surface of the powder 90.

[0026] The mixing device 1 may have a first scraper 13 for scraping the powder 90 from the first transfer section 11. The first scraper 13 may be located at the downstream end 11b of the first transfer section 11. By using the first scraper 13, the powder 90 attached to the first transfer section 11 can be scraped off and made to fall onto the second transfer section 12.

[0027] In addition, the mixing device 1 may have a second scraper 14 for scraping the powder 90 from the second transfer section 12. The second scraper 14 may be located at the downstream end 12b of the second transfer section 12. By using the second scraper 14, the powder 90 attached to the second transfer section 12 can be scraped off and made to fall from the downstream end 12b of the second transfer section 12. Below the downstream end 12b, for example, a container (not shown) for collecting the mixture may be provided. As long as the powder 90 can be scraped off from the transfer section 10, the material of the first scraper 13 and the second scraper 14 is not particularly limited. For example, a metal material such as stainless steel may be used. In addition, the material of the first scraper 13 and the material of the second scraper 14 may be the same as each other or different from each other.

[0028] In the first transfer section 11, the material of the transfer surface 11c may be rubber. Thereby, the sliding of the powder 90 relative to the transfer surface 11c can be reduced. Therefore, as will be described later, it is easy to mold the powder 90 by the powder molding mechanism 20. In addition, in the second transfer section 12, the material of the transfer surface 12c may be stainless steel. Thereby, the deterioration of the transfer surface 12c caused by spraying the liquid from the liquid spraying mechanism 30 described later can be reduced. However, the material of each of the transfer surfaces 11c and 12c is not limited to the above examples. For example, both the transfer surfaces 11c and 12c may be rubber or stainless steel.

[0029] The first transfer speed at which the first transfer section 11 transfers the powder 90 and the second transfer speed at which the second transfer section 12 transfers the powder 90 need to be appropriately adjusted according to the material of the powder 90, but may be, for example, 10 mm / s to 80 mm / s. If the transfer speed is less than 10 mm / s, the productivity of the mixing device 1 for producing the mixture will decrease because the processing amount per unit time decreases. In addition, if the transfer speed is greater than 80 mm / s, it is difficult to control the uniform spraying of the liquid onto the powder 90 formed in a layer shape in the liquid spraying mechanism 30 described later.

[0030] In addition, the first conveying speed and the second conveying speed can also be different from each other. In this case, the thickness of the powder 90 in the second conveying unit 12 can be adjusted according to the difference between the first conveying speed and the second conveying speed. For example, if the second conveying speed is faster than the first conveying speed, the thickness of the powder 90 in the second conveying unit 12 becomes thinner than the thickness of the powder 90 in the first conveying unit 11. If the second conveying speed is slower than the first conveying speed, the thickness of the powder 90 in the second conveying unit 12 becomes thicker than the thickness of the powder 90 in the first conveying unit 11.

[0031] The powder molding mechanism 20 can be configured to be able to mold the powder 90 into a layer. As described above, the powder molding mechanism 20 can be located on the first conveying unit 11. The powder molding mechanism 20 can include a first doctor blade 21, a second doctor blade 22, a first side wall 23, a second side wall 24, and a rear wall 25.

[0032] The first doctor blade 21 and the second doctor blade 22 can be configured to be able to mold the powder 90 in the height direction relative to the conveying unit 10. However, the number of doctor blades included in the powder molding mechanism 20 can be one, or three or more. In the following description, sometimes only the first doctor blade 21 and the second doctor blade 22 are collectively referred to as doctor blades.

[0033] The doctor blade can be in the shape of a plate extending in the width direction of the conveying unit 10. The thickness of the doctor blade in the conveying direction near the lower end portion becomes thinner downward. As long as the powder 90 can be molded, the material of the doctor blade is not particularly limited. For example, a metal material such as stainless steel can be used.

[0034] In addition, the doctor blade can also be in the shape of a flat plate with a constant thickness. In this case, the thickness of the doctor blade can be 0.1 mm to 0.5 mm. If the thickness of the doctor blade is less than 0.1 mm, the doctor blade descending onto the powder 90 is easily pressed by the powder 90 and deformed. If the thickness of the doctor blade is greater than 0.5 mm, the powder 90 pressed by the doctor blade is easily compressed under the doctor blade and does not spread to the front and rear of the doctor blade. In this case, it becomes difficult for the liquid to infiltrate into the compressed powder 90.

[0035] Figure 3 is a cross-sectional view taken along Figure 2 line III-III in the middle. Figure 3 shows the structure of the powder molding mechanism 20. In addition, Figure 3 also shows the powder supply mechanism 29. The powder supply mechanism 29 supplies the powder 90 to the area surrounded by the first side wall 23, the second side wall 24, the rear wall 25, and the first doctor blade 21. The powder supply mechanism 29 can be a part of the mixing device 1 or a device independent of the mixing device 1.

[0036] During the conveying process of conveying powder 90 in the conveying section 10, the heights of the first blade 21 and the second blade 22 vary between a first height and a second height higher than the first height. That is, the first blade 21 and the second blade 22 can be configured to be movable up and down (vibrating). The mixing device 1 may have a drive mechanism (not shown) for varying the heights of the first blade 21 and the second blade 22.

[0037] The up-and-down movement of the blade can be continuous or intermittent. In the following description, it is assumed that the blade moves up and down continuously.

[0038] The first height of the blade is the lower limit of the thickness of the powder 90 formed by the blade. The second height of the blade is the upper limit of the thickness of the powder 90 formed by the blade. The surface of the powder formed by the blade becomes wavy between the first height and the second height of the blade in the conveying direction.

[0039] The first blade 21 forms the powder 90 into a first formed body 91 such that the thickness of the powder 90 is between the first height and the second height of the first blade 21. The material of the first formed body 91 is the same as that of the powder 90. The second blade 22 forms the first formed body 91 into a second formed body 92 such that the thickness of the powder 90 is between the first height and the second height of the second blade 22. The material of the second formed body 92 is the same as that of the powder 90 and the first formed body 91.

[0040] If the height of the blade is constantly the first height, the first formed body 91 is conveyed in a state where its upper surface is in contact with the side surface of the first blade 21. In addition, the second formed body 92 is conveyed in a state where its upper surface is in contact with the side surface of the second blade 22. In this case, the conveyance of the first formed body 91 and the second formed body 92 sometimes gets stuck. By the up-and-down movement of the blade, such sticking can be reduced, and thus the powder 90 can be conveyed smoothly.

[0041] In addition, the powder 90 sometimes contains lumps that are higher than the first height of the blade and can be crushed by the blade. The blade crushes such lumps during the forming process of the powder 90. However, when the powder 90 easily slides on the conveying surface 11c, streaks sometimes occur on the formed body on the downstream side of the lump due to the lump of the powder 90 sliding in front of the blade.

[0042] As described above, if the material of the conveying surface 11c is rubber, the sliding of the powder 90 relative to the conveying surface 11c can be reduced. Therefore, the lumps of the powder 90 can be crushed by the blade, and the powder 90 can be formed into a layer.

[0043] The first height of the blade located on the downstream side in the conveying direction can be lower than the first height of the blade located on the upstream side in the conveying direction. In Figure 1 and Figure 2In the example shown, the first height of the second blade 22 can be lower than the first height of the first blade 21. By using a plurality of blades to form the thickness of the powder 90 in stages, the powder 90 can be evenly diffused in the width direction in stages, and the thickness of the powder 90 can be formed to be constant.

[0044] The thickness of the powder 90 formed by the second blade 22 is the final thickness of the powder 90 formed by the powder forming mechanism 20. The first height of the second blade 22 can be, for example, 4 mm or less. If the first height of the second blade 22 is greater than 4 mm, it is difficult for the liquid sprayed by the liquid spraying mechanism 30 to penetrate below the powder 90 formed by the second blade 22.

[0045] The cycle of the up-and-down movement of the blade depends on the conveying speed at which the conveying unit 10 conveys the powder 90. In other words, the cycle of the up-and-down movement of the blade can be determined according to the moving distance of the powder 90, rather than according to time. Specifically, during one up-and-down movement of the blade, the powder 90 can move 0.7 mm to 2.5 mm. According to the relationship between this distance and the conveying speed of the powder 90, the cycle of the up-and-down movement of the blade in terms of time is determined.

[0046] If the distance that the powder 90 moves during one up-and-down movement of the blade is less than 0.7 mm, the forming efficiency of the powder 90 decreases. If the distance that the powder 90 moves during one up-and-down movement of the blade is greater than 2.5 mm, the forming of the powder 90 is insufficient.

[0047] In addition, the distance that the powder 90 moves during one up-and-down movement of the blade can vary depending on the first height of each blade. Specifically, it can be such that, compared with a blade having a lower first height, in a blade having a higher first height, the distance that the powder 90 moves during one up-and-down movement of the blade is longer.

[0048] As described above, the blade crushes the lumps of the powder 90 during the forming process of the powder 90. Compared with a blade having a lower first height, a blade having a higher first height crushes larger lumps. Since the proportion of such lumps is small, it can be that during one up-and-down movement of the blade that crushes such lumps, the powder 90 moves a longer distance.

[0049] Among all the blades, for a blade with a shorter up-and-down movement cycle, the state of the formed body of the powder 90 is better. However, the shorter the up-and-down movement cycle, the greater the load on the drive mechanism of the blade. Therefore, the up-and-down movement cycle of the blade can be made longer according to the first height.

[0050] In addition, in each of the first blade 21 and the second blade 22, the difference (variation range) between the first height and the second height may be 2 mm to 4 mm. If the variation range is less than 2 mm, it may not be possible to smoothly convey the powder 90 formed by each blade. If the variation range is greater than 4 mm, when setting the conveying speed of the powder 90 and the cycle of the vertical movement of the blade as described above, the speed of the blade will become too large. As a result, the load on the drive mechanism that varies the height of the blade increases, which may shorten the life of the drive mechanism.

[0051] In addition, the variation ranges of the heights of each of the first blade 21 and the second blade 22 may be the same as each other or different from each other. For example, by making the variation range of the second blade 22 smaller than that of the first blade 21, the unevenness difference of the powder 90 in the conveying direction can be made smaller.

[0052] The first height and the second height of each of the first blade 21 and the second blade 22 can be appropriately set so that the powder 90 is formed in stages. Specifically, the first height and the second height of the second blade 22 are set as the lower limit and the upper limit of the final thickness of the powder 90. The first height and the second height of the first blade 21 can be set to be 0 mm to 4 mm higher than the first height and the second height of the second blade 22, respectively. If the number of blades is three or more, the differences in the first height and the second height between adjacent blades can both be set to 0 mm to 4 mm.

[0053] The first side wall 23 can extend along the conveying direction of the powder 90 of the conveying unit 10. The second side wall 24 can be opposite to the first side wall 23. That is, the first side wall 23 and the second side wall 24 are side walls provided at both ends in the width direction of the area where the powder 90 is conveyed. The first side wall 23 and the second side wall 24 can be located on both sides of the first blade 21 and the second blade 22. In addition, the first side wall 23 and the second side wall 24 are provided in contact with the conveying surface 11c of the conveying unit 10.

[0054] The powder 90 conveyed by the first conveying unit 11 is formed in the height direction by the blade. And this powder 90 is formed in the width direction by the first side wall 23 and the second side wall 24. As a result, the deviation of the amount of the powder 90 per unit length in the conveying direction can be reduced. Therefore, the ratio between the powder 90 and the liquid sprayed by the liquid spraying mechanism 30 can be made uniform.

[0055] The rear wall 25 is located on the upstream side in the conveyance direction of the first side wall 23 and the second side wall 24. In the mixing device 1, the powder supply mechanism 29 can supply the powder 90 to the area defined by the first side wall 23, the second side wall 24, the rear wall 25, and the first wiper 21. That is, the rear wall 25 defines the upstream end in the conveyance direction of the area for supplying the powder 90. However, in the mixing device 1, the rear wall 25 can also be omitted.

[0056] The liquid spraying mechanism 30 sprays liquid onto the powder 90 formed in a layer. The liquid is, for example, a vehicle or a solvent added to the powder 90 composed of ceramic particles. As a specific example of the liquid, an aqueous solution of a water-soluble acrylic resin or an aqueous solution of a polysaccharide can be cited. The liquid spraying mechanism 30 can be located on the downstream side of the powder forming mechanism 20 in the conveyance direction in which the first conveyance unit 11 conveys the powder 90. The liquid spraying mechanism 30 can be located on the second conveyance unit 12. In Figure 1 and Figure 2 the mixing device 1 has two liquid spraying mechanisms 30 arranged in the width direction. However, the number of the liquid spraying mechanisms 30 provided in the mixing device 1 is not limited to two, as long as it can spray liquid onto all of the powder 90 conveyed by the second conveyance unit 12.

[0057] Figure 4 is a cross-sectional view taken along line IV-IV in Figure 2 . Figure 4 The structure of one liquid spraying mechanism 30 is shown. As Figure 4 shown, the liquid spraying mechanism 30 can have a nozzle 31 and a hood 32.

[0058] The nozzle 31 can be configured to be able to spray liquid onto the powder 90 on the conveyance unit 10. The nozzle 31 can be a so-called single-fluid nozzle that only sprays liquid. If the nozzle 31 is set as a so-called two-fluid nozzle that sprays liquid and air, the powder 90 may be scattered by the air sprayed from the nozzle 31. By setting the nozzle 31 as a single-fluid nozzle, the scattering of the powder 90 can be reduced. The nozzle 31 can be connected to a pump (not shown) that supplies the liquid. The spraying amount of the liquid from the nozzle 31 can be appropriately determined in consideration of the desired ratio of the powder 90 to the liquid, the conveyance speed of the powder 90 by the conveyance unit 10, and the amount of the powder 90 per unit length in the conveyance direction.

[0059] The hood 32 restricts the spraying range of the liquid sprayed by the nozzle 31. The hood 32 can be in a cylindrical shape having an upper surface on which the nozzle 31 is mounted and side surfaces that restrict the spraying range of the liquid. The nozzle 31 can be located on the central axis of the cylindrical shape of the hood 32. However, the shape of the hood 32 is not limited to this.

[0060] When observed from a direction perpendicular to the conveying surface 12c, the area for conveying the powder 90 includes the entire cover 32. Therefore, the liquid sprayed outside the spraying range of the liquid restricted by the cover 32 from the nozzle 31 collides with the side surface of the cover 32 and falls onto the powder 90 located below it. Thus, for example, the possibility of spraying the liquid outside the area where the powder 90 is located on the conveying unit 10 can be reduced. Therefore, the spraying range of the liquid from the nozzle 31 can be restricted to the area where the powder 90 is located, so that the ratio of the powder 90 to the liquid can be made uniform.

[0061] The material of the cover 32 can be a material that does not react with the liquid. Additionally, the material of the cover 32 can be a material with high hydrophobicity. Specific examples of the material of the cover 32 include stainless steel or fluororesin.

[0062] The height H of the end portion 32a of the cover 32 relative to the conveying unit 10 can be set to be 1 mm to 6 mm higher than the thickness of the formed powder 90. For example, if the thickness of the formed powder 90 is set to 4 mm, the height H of the end portion 32a relative to the conveying unit 10 can be 5 mm to 10 mm. If H is less than 5 mm, when there is a deviation in the thickness of the powder 90, the possibility of the powder 90 coming into contact with the cover 32 becomes high. If H is higher than 10 mm, the liquid may be sprayed to the outside between the powder 90 and the end portion 32a. That is, the spraying range of the liquid cannot be sufficiently restricted.

[0063] Figure 5 It is a side view of the cover 32. As Figure 5 shown, the end portion 32a of the cover 32 opposite to the conveying unit 10 can also have a plurality of convex portions 32b protruding toward the conveying unit 10. The convex portions 32b can be located on the entire end portion of the cover 32 opposite to the conveying unit 10. In other words, the entire end portion 32a can be serrated. For convenience, in Figure 5 only a part of the convex portions 32b are labeled with reference numerals. The above H represents the height of the lower end of the convex portion 32b relative to the conveying unit 10.

[0064] With the cover 32 having such a shape, the liquid adhering to the cover 32 is dispersed from each of the plurality of convex portions 32b and falls onto the powder 90. Therefore, compared with the case where the liquid adhering to the cover 32 falls onto the powder 90 from a single point on the end portion 32a, for example, the deviation in the spraying amount of the liquid relative to the powder 90 at each position can be reduced.

[0065] However, the end portion 32a does not necessarily have convex portions 32b on the entire part opposite to the conveying unit 10. If at least a part of the end portion 32a has convex portions 32b, compared with the case where there are no convex portions 32b, the deviation in the spraying amount of the liquid can be reduced.

[0066] The moving mechanism 40 can be configured to be able to move the powder body 90 in a direction different from the conveying direction on the conveying surface 12c. The moving mechanism 40 is located on the downstream side of the liquid spraying mechanism 30 in the conveying direction. The moving mechanism 40 can move the powder body 90 in a state where the liquid has been sprayed by the liquid spraying mechanism 30 in a direction in which the width of the area for conveying the powder body 90 becomes narrower.

[0067] The nozzle 31 can spray the liquid in a circular range, for example, with less in the vicinity of the center and more in the vicinity of the outer edge. In a state where the liquid is sprayed by the liquid spraying mechanism 30 having such a nozzle 31, the ratio of the liquid to the powder body 90 is likely to be higher at the center in the width direction of the area for conveying the powder body 90 than at the end in the width direction. By moving the powder body 90 from the end side in the width direction to the center side by the moving mechanism 40, the powder body 90 and the liquid can be uniformly mixed.

[0068] In Embodiment 1, the moving mechanism 40 has four rotating bodies 41, 42, 43, and 44. At least a part of each rotating body 41 can be located on the conveying part 10, specifically, on the second conveying part 12. In Figure 1 and Figure 2 , all of the rotating bodies 41 to 44 are located above the second conveying part 12.

[0069] The rotating bodies 41 to 44 only need to have a material that does not react with the powder body 90 and the liquid sprayed by the liquid spraying mechanism 30. The material of the rotating bodies 41 to 44 can be, for example, fluororesin or polyoxymethylene. If the rotating bodies 41 to 44 are such materials, the adhesiveness of the mixture of the powder body 90 and the liquid becomes low. In addition, the rotating bodies 41 to 44 have wear resistance. Furthermore, the rotating bodies 41 to 44 are not easily damaged by the stainless steel constituting the conveying surface 12c.

[0070] The rotating bodies 41 to 44 are located on the conveying part 10 so as to cross the ends in the width direction of the area for conveying the powder body 90. In addition, the rotating bodies 41 to 44 rotate in a direction that moves the powder body 90 toward the vicinity of the center of the second conveying part 12 on the upstream side in the conveying direction. As a result, the powder body 90 located near the ends of the area for conveying the powder body 90 moves to the vicinity of the center of the area.

[0071] Specifically, the rotating bodies 41 and 42 are arranged side by side in the width direction at the same position in the conveying direction. The rotating bodies 41 and 42 are respectively located at both ends in the width direction of the area where the powder 90 is conveyed. The rotating body 43 is on the downstream side of the rotating bodies 41 and 42 in the conveying direction and is located on one end side in the width direction of the area where the powder 90 is conveyed. The rotating body 44 is on the downstream side of the rotating body 43 in the conveying direction and is located on the side opposite to the rotating body 43 in the width direction of the area where the powder 90 is conveyed. That is to say, the rotating bodies 43 and 44 are arranged offset from each other in the width direction. Thereby, each rotating body 41 can move the powder 90 from the end side of the conveying part 10 to the central side, and make the powder 90 and the liquid mix more evenly.

[0072] In addition, one side of the rotating body 43 in the width direction of the area where the powder 90 is conveyed is located at the most downstream side. The side of the rotating body 44 opposite to the rotating body 43 in the width direction of the area where the powder 90 is conveyed is located at the most downstream side. At least a part of these rotating bodies 43 and 44 can be located substantially at the center in the width direction of the area where the powder 90 is conveyed on the upstream side of the moving mechanism 40. For example, the area from the center in the width direction of the area where the powder 90 is conveyed on the upstream side of the moving mechanism 40 to within one-eighth of the length in the width direction of this area can be regarded as the substantial center.

[0073] The rotation speeds of the rotating bodies 41 to 44 can be 100% to 500% of the conveying speed at which the second conveying part 12 conveys the powder 90. The rotation speeds of the rotating bodies 41 to 44 mentioned here refer to the moving speeds of any points located on the outer edge parts in the circumferential directions of the rotating bodies 41 to 44.

[0074] If the rotation speeds of the rotating bodies 41 to 44 are less than 100% of the conveying speed of the powder, the detachability of the mixture of the powder 90 and the liquid from the rotating bodies 41 to 44 decreases. Specifically speaking, the smaller the rotation speeds of the rotating bodies 41 to 44 are, the longer the contact time between the mixture and the surfaces of the rotating bodies 41 to 44 is. As a result, the cumulative value of the pressure formed by the subsequent mixture conveyed by the second conveying part 12 increases, and the detachability of the mixture from the rotating bodies 41 to 44 decreases. Especially when the rotation speeds of the rotating bodies 41 to 44 are less than 100% of the conveying speed of the powder, the detachability of the mixture from the rotating bodies 41 to 44 decreases to the extent that it hinders the operation of the mixing device 1.

[0075] If the rotation speeds of the rotating bodies 41 to 44 are greater than 500% of the conveying speed of the powder 90, the difference between the conveying speed at which the second conveying part 12 conveys the powder 90 and the rotation speeds of the rotating bodies 41 to 44 becomes too large. As a result, the rotating bodies 41 to 44 are worn, and the shear load on the mixture becomes large.

[0076] The rotation axes of the rotating bodies 41 to 44 can be substantially perpendicular to the conveying surface 12c. For example, if the inclination of the rotation axis with respect to the direction perpendicular to the conveying surface is 5° or less, it can be considered that the rotation axis is substantially perpendicular to the conveying surface 12c.

[0077] The shape of the cross-section of the plane including the rotation axes of the rotating bodies 41 to 44 can be an isosceles trapezoid with the upper side shorter than the lower side. By having such a shape for the cross-section of the rotating bodies 41 to 44, it becomes easier for the mixture of the powder 90 and the liquid to separate from the second conveying unit 12. The shorter the upper side in the above cross-section, the higher the separation property. On the other hand, the shorter the upper side in the above cross-section, the lower the effect of mixing the powder 90 and the liquid. However, the shape of the cross-section of the rotating body 41 is not limited to this, and for example, it can also be a rectangle or the like.

[0078] In addition, the moving mechanism 40 is not limited to having four rotating bodies 41 to 44. If the moving mechanism 40 has rotating bodies, it can have at least one rotating body on each side in the width direction of the area for conveying the powder 90. Furthermore, the moving mechanism 40 is not limited to having rotating bodies.

[0079] The control unit 50 can be configured to be able to uniformly control the operations of each part of the mixing device 1. For example, the control unit 50 can control the up and down movement of the first scraper 21 and the second scraper 22 by controlling the drive mechanism. In addition, the control unit 50 can also control the conveying speed of the powder 90 conveyed by the first conveying unit 11 and the second conveying unit 12. In addition, the control unit 50 can also control the spraying amount of the liquid from the nozzle 31. In addition, the control unit 50 can also control the rotation speed of the rotating bodies 41 to 44.

[0080] The storage unit 60 is a storage medium that stores the information required for the control unit 50 to perform control. The storage unit 60 can store, for example, programs for the above various controls. However, the mixing device 1 does not necessarily have to have the storage unit 60, and it can also be communicably connected to an external storage device that stores the information required for the control unit 50 to perform control.

[0081] (Method for manufacturing a mixture)

[0082] Figure 6 It is a flowchart showing an example of a method for manufacturing a mixture using the mixing device 1. Hereinafter, an example of a method for manufacturing a mixture using the mixing device 1 will be described.

[0083] In the mixing device 1, the control unit 50 conveys the powder 90 using the conveying unit 10 (S1: Conveying step). The control unit 50 continuously performs the conveyance of the powder 90 during the manufacturing process of the mixture.

[0084] The control unit 50 forms the powder 90 being transported in step S1 into a layer using the powder molding mechanism 20 (S2: powder molding step). Next, the control unit 50 sprays a liquid onto the powder 90 that has been formed into a layer in step S2 using the liquid spraying mechanism 30 (S3: liquid spraying step). Furthermore, the control unit 50 uses the moving mechanism 40 to move the powder 90 onto which the liquid has been sprayed in step S3 in a direction different from the transportation direction (S4).

[0085] Through the above processes, it is possible to manufacture a mixture using the mixing device 1. However, the method for manufacturing a mixture using the mixing device 1 is not limited to the above example. For example, the control unit 50 can also control the transport unit 10 to intermittently transport the powder 90.

[0086] (Example)

[0087] Using the mixing device 1, a mixture of alumina powder and a water-soluble acrylic resin is manufactured. Specifically, the alumina powder with a particle size D50 = 1.5 μm is formed into a layer with an average thickness of 3 mm using the powder molding mechanism 20. A 5 wt% aqueous solution of the water-soluble acrylic resin (acrylic aqueous solution) is sprayed onto the layered alumina powder using the liquid spraying mechanism 30. The weight ratio of the alumina powder to the acrylic aqueous solution is 81:19.

[0088] The mixture obtained under the above conditions is granular. This mixture can be formed into a desired shape, for example, by a known stamping method using a mold.

[0089] In the mixture obtained under the above conditions, the volume fraction of the alumina powder is 52.2 vol%, and the volume fraction of the acrylic aqueous solution is 47.8 vol%. Since the mixture with this volume fraction has low fluidity, it is difficult to knead a mixture with the same volume fraction using, for example, a conventionally known kneader with rotating blades. That is, according to the mixing device 1, it is possible to obtain a mixture with a high volume fraction of powder that is difficult to knead in a conventionally known kneader.

[0090] As a method for obtaining a ceramic structure with a desired shape, a method can be cited in which, after forming a mixture obtained by mixing a ceramic powder and a liquid containing a binder, the binder is removed by sintering. The sintering of the mixture is carried out at a temperature of 300 °C or higher. At this time, the binder turns into carbon dioxide and water and is released into the atmosphere.

[0091] According to the mixing device 1, by manufacturing a mixture with a small amount of binder, it is possible to reduce the amount of carbon dioxide released during the manufacturing process of the ceramic structure. Such an effect contributes, for example, to achieving Goal 13, "Measures to combat climate change," of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0092] [Embodiment 2]

[0093] Figure 7 This is a perspective view showing the structure of the mixing device 1A of Embodiment 2. Figure 8 This is a cross-sectional view showing the structure of the powder molding mechanism 20A. As Figure 7 and Figure 8 shown, the mixing device 1A includes a conveying unit 10A, a powder molding mechanism 20A, and a moving mechanism 40A.

[0094] In addition, the mixing device 1A has a liquid spraying mechanism 30 having the same structure as the liquid spraying mechanism 30 of the mixing device 1. However, while the mixing device 1 has two liquid spraying mechanisms 30, the mixing device 1A has only one liquid spraying mechanism 30. Also, the mixing device 1A may have a control unit and a storage unit (not shown) for controlling the conveying unit 10A, the powder molding mechanism 20A, the liquid spraying mechanism 30, and the moving mechanism 40A.

[0095] The conveying unit 10A conveys powder. The conveying unit 10A does not include the first conveying unit 11 and the second conveying unit 12, but is a single conveying unit, which is different from the conveying unit 10 in this regard. Therefore, the powder molding mechanism 20A, the liquid spraying mechanism 30, and the moving mechanism 40A are located on this single conveying unit.

[0096] In addition, a third scraper 15 for scraping powder from the conveying unit 10A may be provided at the end on the downstream side of the conveying unit 10A in the conveying direction. With the third scraper 15, powder can be scraped from the conveying unit 10A and made to fall from the end of the conveying unit 10A. For example, a container for collecting the mixture may be provided below the end of the conveying unit 10A.

[0097] The powder molding mechanism 20A forms the powder into a layer. The powder molding mechanism 20A does not have the first scraper 21 and the second scraper 22, but only has a single third scraper 26 (scraper), which is different from the powder molding mechanism 20 in this regard.

[0098] During the process of the conveying unit 10A conveying powder, the height of the third scraper 26 varies between a first height and a second height higher than the first height. The third scraper 26 forms the powder into the first height of the third scraper 26.

[0099] In the powder molding mechanism 20A, the height of the powder formed by the third scraper 26 becomes the height of the finally formed powder. Therefore, the first height of the third scraper 26 is set as the height of the finally formed powder.

[0100] Figure 9It is a top view of the moving mechanism 40A and its periphery. The moving mechanism 40A moves the powder in a direction different from the conveying direction of the powder by the conveying unit 10A on the conveying surface of the conveying unit 10A for conveying the powder. The moving mechanism 40A has two rotating bodies 45 and 46, which is different from the moving mechanism 40 in this regard. The rotating body 45 is located on one side in the width direction of the area for conveying the powder 90. The rotating body 46 is located on the side opposite to the rotating body 45 in the width direction of the area for conveying the powder 90.

[0101] As described above, compared with the mixing device 1, the mixing device 1A has a simplified structure. With such a mixing device 1A, it is also possible to obtain a mixture of powder and liquid with a high volume fraction of the powder. Therefore, for example, the amount of adhesive used in the manufacturing process of the ceramic structure can be reduced, and the amount of carbon dioxide released can also be reduced.

[0102] The invention of the present disclosure has been described based on the respective drawings and embodiments. However, the invention of the present disclosure is not limited to the above-described embodiments. That is, the invention of the present disclosure can be variously modified within the scope shown in the present disclosure, and embodiments obtained by appropriately combining the technical means respectively disclosed in different embodiments are also included in the technical scope of the invention of the present disclosure. That is to say, it should be noted that those skilled in the art can easily make various deformations or corrections based on the present disclosure. It should also be noted that these deformations or corrections are included within the scope of the present disclosure.

[0103] For example, conveying side walls can be provided at both ends in the width direction on the downstream side of the powder molding mechanism 20. The conveying side walls are provided in contact with the conveying surface 11c (12c) of the conveying unit 10. In this way, by providing the conveying side walls on the conveying surface 11c (12c), the length of the powder in the width direction from the powder molding mechanism 20 can be controlled to be constant. Therefore, it is possible to reduce the situation where the width direction of the powder changes due to the influence of vibration during conveying, and as a result, the deviation of the thickness of the powder can be reduced.

[0104] In addition, as the moving mechanism 40, when a rotating body is provided on one end side in the width direction of the area for conveying the powder 90, a side wall for the moving mechanism can be provided on the other end side in the width direction. In this case, it is possible to use the side wall for the moving mechanism to reduce the situation where the powder 90 passing through the rotating body diffuses to the other end in the width direction.

[0105] Explanation of reference numerals:

[0106] 1, 1A Mixing device

[0107] 10, 10A Conveying unit

[0108] 11 First conveying unit

[0109] 12 Second conveying part

[0110] 20, 20A Powder molding mechanism

[0111] 21 First scraper (scraper)

[0112] 22 Second scraper (scraper)

[0113] 23 First side wall

[0114] 24 Second side wall

[0115] 26 Third scraper (scraper)

[0116] 30 Liquid spraying mechanism

[0117] 31 Nozzle

[0118] 32 Cover

[0119] 32a Protrusion

[0120] 40, 40A Moving mechanism

[0121] 41, 42, 43, 44, 45, 46 Rotating body

Claims

1. A mixing device, wherein, it has: a conveying part for conveying powder; a powder molding mechanism for molding the powder into a layered form; and a liquid spraying mechanism for spraying liquid onto the powder molded into a layered form, the powder molding mechanism has one or more scrapers for molding the powder in the height direction relative to the conveying part, during the conveying process of the powder by the conveying part, the height of the scraper relative to the conveying part varies between a first height and a second height higher than the first height.

2. The mixing device according to claim 1, wherein, the powder molding mechanism further has: a first side wall extending along the conveying direction of the powder by the conveying part; and a second side wall opposite to the first side wall.

3. The mixing device according to claim 2, wherein, the mixing device has a plurality of the scrapers along the conveying direction of the powder by the conveying part, and the first height of the scraper located on the downstream side in the conveying direction is lower than the first height of the scraper located on the upstream side in the conveying direction.

4. The mixing device according to any one of claims 1 to 3, wherein, the liquid spraying mechanism has: a nozzle for spraying the liquid onto the powder on the conveying part; and a hood for restricting the spraying range of the liquid.

5. The mixing device according to claim 4, wherein, the end of the hood opposite to the conveying part has a plurality of convex parts protruding towards the conveying part.

6. The mixing device according to any one of claims 1 to 5, wherein, the conveying part includes: a first conveying part to which the powder is supplied; and a second conveying part arranged lower than the first conveying part for conveying the powder falling from the first conveying part.

7. The mixing device according to claim 6, wherein, the first conveying speed of the powder by the first conveying part is different from the second conveying speed of the powder by the second conveying part.

8. The mixing device according to any one of claims 1 to 7, wherein, on the conveying surface of the powder by the conveying part, a moving mechanism is provided on the downstream side in the conveying direction of the liquid spraying mechanism, and the moving mechanism moves the powder in a direction different from the conveying direction of the powder by the conveying part.

9. The mixing device according to claim 8, wherein, the moving mechanism has a rotating body with at least a part located on the conveying part.

10. A method for manufacturing a mixture, using a mixing device, wherein, the mixing device has: a conveying part for conveying powder; a powder molding mechanism for molding the powder into a layered form; and a liquid spraying mechanism for spraying liquid onto the powder molded into a layered form, the powder molding mechanism has one or more scrapers for molding the powder in the height direction relative to the conveying part, during the conveying process of the powder by the conveying part, the height of the scraper relative to the conveying part varies between a first height and a second height higher than the first height, the method for manufacturing the mixture includes: a conveying step of conveying the powder by using the conveying part; A powder forming step of forming the powder being transported in the transportation step into a layered form by using the powder forming mechanism; and A liquid spraying step of spraying a liquid onto the powder formed into a layered form in the powder forming step by using the liquid spraying mechanism.

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