Mixing body, stirring blade, stirring device, stirring method, method for assembling stirring blade, stir bar, mixing device, and mixing system

Abstract

Provided are a mixing body and the like that make it possible to highly efficiently mix even a highly viscous fluid.　A stirring blade 2 is formed by holding, by means of a holder 21 and an annular plate 22, a mixer body 1 having provided thereto spacers 14 and laminates 13 formed of a plurality of mixing elements 11, 12. Blade plates 23 are arranged in a hollow portion 15 formed inside the stirring blade 2. Due to rotation of the stirring blade 2, a fluid drawn in from the hollow portion 15 gets mixed as a result of being split, merged, etc., when passing through a flow passage 16 that is formed from the spacers 14 inside the stirring blade 2 and through a flow passage that includes interconnecting flow passages formed from small through-holes 113, 123, and flows out from the outer circumference of the stirring blade 2.

Description

Mixture, stirring blade, stirring device, stirring method, stirring blade assembly method, stirring bar, mixing device, and mixing system

[0001] The present invention relates to a technique for mixing or stirring fluids, and relates to a mixture, an agitating blade, an agitating device, a stirring method, a method for assembling an agitating blade, a stirrer, a mixing device, and a mixing system.

[0002] Agitator blades are widely used to agitate fluids in vessels such as stirring tanks. While blade-type agitator blades, such as paddle blades with flat blades and turbine blades, are widely used, various shapes of agitator blades have been proposed to improve agitation efficiency. For example, the agitator blades described in Patent Document 1 have four sets of agitators, with two partial agitators per set per rotation plane, attached to both sides of a support attached to the agitator shaft. However, with these agitator blades, the fluid is only mixed by the partial agitators attached to the support, so the mixing efficiency is limited.

[0003] On the other hand, the agitator described in Patent Document 2 is a stacked agitator in which a mixing element, which is made of stacked perforated plate-like stacking elements, is sandwiched between a first plate and a second plate and a rotating shaft is attached. This agitator achieves high mixing by circulating the fluid sucked in from a hollow portion formed inside the mixing element and discharging it from the outer periphery of the agitator through a flow path that is connected by the first through-holes of the stacking elements formed inside the mixing element. Because the fluid is sucked in from the hollow portion, it is possible to efficiently mix the fluid inside the agitator tank overall. However, because there is high resistance when the fluid passes through the mixing element, the amount of suction is small, particularly when the viscosity of the fluid is high, and the agitation efficiency is reduced.

[0004] Patent No. 3174235 Publication Patent No. 5500575

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a mixture that can mix even highly viscous fluids with high efficiency, and an agitator blade equipped with the mixture, an agitator, a mixing method, a method for assembling the agitator blade, an agitator, a mixing device, and a mixing system.

[0006] The mixture according to the present invention is a mixture in which a plurality of mixing elements and spacers arranged between the mixing elements are stacked, wherein the mixing element has one large through hole in approximately the center and a plurality of small through holes arranged circumferentially so as to surround the large through hole, and the mixing elements are arranged such that, in a plan view of the mixing element, some or all of the small through holes partially overlap with the small through holes of adjacent mixing elements with their positions shifted, and the large through holes of the mixing elements are connected continuously or intermittently in the stacking direction of the mixing elements to form a hollow section inside the mixture.

[0007] Furthermore, the agitator blade according to the present invention comprises the mixture, a holder and an annular plate arranged opposite each other with the mixture sandwiched therebetween, the annular plate having one through-hole in approximately the center thereof, the through-hole communicating with a hollow portion formed inside the mixture, and the holder being attached to a rotating shaft that is driven to rotate.

[0008] The agitating impeller according to the present invention is the agitating impeller, wherein the hollow portion of the mixer is provided with a plurality of flat blades extending in the stacking direction of the mixing elements.

[0009] Furthermore, the agitator blade according to the present invention is the agitator blade, in which the radial walls of the mixing element are continuously or intermittently connected to the hollow portion of the mixture, forming a plurality of flat blade portions extending continuously or intermittently in the stacking direction of the mixing elements.

[0010] In another embodiment of the present invention, the mixing element, holder, and annular plate forming the agitator blade may be provided with a plurality of fastening through-holes, and the agitator blade may be integrally fixed with bolts and nuts disposed in the fastening through-holes. A stirring device may be constructed in which the agitator blade is disposed in a fluid within a stirring vessel. As a stirring method, the mixture may be rotated by itself, causing the fluid that flows into the mixture from the large through-hole of the mixing element via the through-hole of the annular plate to flow out from the outer periphery of the mixing element via a plurality of small through-holes. In addition, in the method of assembling the agitator blade, the agitator blade may be integrally fixed by inserting bolts through the fastening through-holes and spacers of the mixing element, holder, and annular plate, and by tightening the ends of the bolts with nuts.

[0011] The stirring bar according to the present invention is a stirring bar in which the mixture is placed on a base having a magnet or a magnetic material. This stirring bar may include a plurality of flat blades extending in the stacking direction of the mixing elements.

[0012] Furthermore, the mixing device according to the present invention is a mixing device that continuously mixes fluids within a substantially cylindrical casing using the agitating blade, wherein the casing has a fluid inlet and a fluid outlet, and when the agitating blade is driven to rotate within the casing, fluid sucked in from the fluid inlet provided on the circular end face of the casing flows into the agitating blade, and the fluid discharged from the outer periphery of the agitating blade is discharged from the fluid outlet provided on the cylindrical side face of the casing.

[0013] A mixing system according to the present invention is a mixing system including the above-described mixing device, and further including a circulation path for a fluid from the discharge port to the suction port of the mixing device.

[0014] As described above, according to the present invention, a flow path with low flow resistance in which a spacer is arranged is formed in the mixer, so that by rotating the mixer, the fluid that flows into the mixer flows from the hollow portion formed inside the mixer through the flow path created by the spacer and the flow path via the multiple small through-holes in the mixing element, and then flows out from the outer periphery of the mixer, so that even if the fluid is highly viscous, it can be mixed highly efficiently.Furthermore, according to the method of assembling an agitator impeller of the present invention, the agitator impeller can be assembled efficiently.

[0015] It is an exploded perspective view showing a mixture according to an embodiment of the mixture. It is a plan view of each mixing element forming the mixture (Figs. 2(a) and (b)) and a plan view showing the overlap of the mixing elements (Fig. 2(c)). It is a perspective view of a spacer forming the mixture. It is an exploded perspective view showing a stirring blade according to Embodiment 1 of the stirring blade. It is an external side view of the stirring blade according to Embodiment 1. It is a perspective view showing a holder constituting the stirring blade according to Embodiment 1. It is a perspective view showing an annular plate constituting the stirring blade according to Embodiment 1. It is a schematic perspective cross-sectional view of the stirring blade according to Embodiment 1. It is a schematic cross-sectional view (Fig. 9(a)) in the cross-sectional direction showing the state of the fluid flowing when the stirring blade according to Embodiment 1 rotates in the stirring tank and stirs, and a schematic view (Fig. 9(b)) showing the flow of the fluid inside the stirring blade. It is a plan view of each mixing element forming the stirring blade according to Modification 1 of Embodiment 1 (Figs. 10(a) and (b)) and a plan view showing the overlap of the mixing elements (Fig. 10(c)). It is a plan view of each mixing element forming the stirring blade according to Modification 2 of Embodiment 1 (Figs. 11(a) and (b)) and a plan view showing the overlap of the mixing elements (Fig. 11(c)). It is a schematic perspective cross-sectional view of the stirring blade according to Modification 2 of Embodiment 1. It is a perspective view of a connecting spacer forming the stirring blade according to Modification 3 of Embodiment 1 (Fig. 13(a)) and a schematic perspective cross-sectional view of the stirring blade (Fig. 13(b)). It is an exploded perspective view showing a stirring blade according to Embodiment 2. It is an exploded perspective view showing a stirring blade according to Modification 1 of Embodiment 2. It is a perspective view of a stirrer according to an embodiment of the stirrer. It is a cross-sectional view showing the state of fluid flowing inside a mixing device according to Embodiment 1 of the mixing device. It is a configuration diagram schematically showing the state of mixing fluid by an example of use of a mixing system using the mixing device. It is a perspective view showing a kai cross blade as a blade type stirring blade used in the comparative example. It is an external side view (Fig. 20(a)) and a schematic perspective cross-sectional view (Fig. 20(b)) showing a laminated stirring blade used in the comparative example. It is a graph showing the change over time of the viscosity of the mixed liquid in the dissolution experiment of the polymer flocculant obtained in Example-1 and Comparative Examples-1 and Comparative Examples-2. It is a graph showing the change over time of the viscosity of the mixed liquid in the dissolution experiment of the polymer flocculant obtained in Example-1, Example-2, and Example-3.

[0016] (Embodiment of Mixture) As shown in Fig. 1, the mixture 1 is formed from three stacks 13 in which two types of substantially circular mixing elements 11, 12 (see Fig. 2) are stacked one by one, and a plurality of cylindrical spacers 14 (see Fig. 3) arranged between and at the upper end of the stacks 13. Bolts B are inserted through four bolt holes 111, 121 provided in the mixing elements 11, 12 and the spacers 14, and together with nuts N, serve as fastening means to fix the mixture 1 together.

[0017] The mixing elements 11 and 12 have approximately the same outer diameter, and each has a substantially circular large through hole 112 and 122 in the center, and a plurality of substantially rectangular small through holes 113 and 123 arranged circumferentially around the periphery. The large through holes 112 and 122 have approximately the same inner diameter and are substantially concentric, so that stacking the mixing elements 11 and 12 forms a hollow portion 15 inside the mixer 1. The mixing elements 11 and 12 are partially separated by spacers 14 in the stacking direction, so the large through holes 112 and 122 of the mixing elements 11 and 12 that form the hollow portion 15 are not continuous in the stacking direction.

[0018] 2(a) and 2(b), the small through holes 113, 123 of each mixing element 11, 12 are substantially rectangular through holes and are arranged in a staggered pattern in the radial direction. The radial pitch of each small through hole 113, 123 is the same, but the circumferential pitch increases from the inner periphery to the outer periphery so that the number of small through holes 113, 123 on each circumference is the same. The small through holes 113, 123 of each mixing element 11, 12 are arranged so that their positions are shifted relative to the small through holes 123, 113 of adjacent mixing elements 12, 11 and partially overlap in the radial and circumferential directions. Therefore, by stacking the mixing elements 11, 12, as shown in FIG. 2(c), each small through hole 113, 123 is connected in the direction in which the mixing elements 11, 12 extend. Since the small through holes 113, 123 are arranged as described above, the fluid can flow from the hollow portion 15 of the mixture 1 to the outer periphery, and at that time, the fluid is highly mixed by repeatedly dividing, merging, reversing, turbulent flow, vortex flow, collision, etc.

[0019] (Embodiment 1 of the Stirring Impeller) An exploded perspective view of the stirring impeller 2 according to embodiment 1 is shown in Figure 4, and an external side view is shown in Figure 5. The stirring impeller 2 has a substantially disk-shaped holder 21 shown in Figure 6 arranged above the mixer 1, and a substantially disk-shaped annular plate 22 shown in Figure 7 arranged below, and four blade plates 23 extending in the stacking direction of the mixing elements 11 and 12 are arranged in the hollow portion 15 of the mixer 1. In this embodiment, four blade plates 23 are arranged, but this is not limited to this and there may be more or less than four.

[0020] A mounting hole 211 is arranged in the center of the holder 21, to which the rotating shaft 24 is attached by an appropriate method such as screwing. Four fan-shaped holes 212 through which the fluid flows in are formed surrounding the mounting hole 211, and a cross-shaped support member 213 is formed between each fan-shaped hole 212. Four bolt holes 214 are provided on the outer periphery of the holder 21. The annular plate 22 has a through hole 221 in the center through which the fluid flows in, and four bolt holes 222 on the outer periphery. Therefore, the mixture 1 is sandwiched between the holder 21 and the annular plate 22, and bolts B are inserted through the bolt holes 214 of the holder 21, the bolt holes 222 of the annular plate 22, the bolt holes 111, 121 of the mixing elements 11 and 12 constituting the mixture 1, and the spacer 14 and fastened with nuts N. The blade plate 23 is arranged in the hollow portion 15, and the agitator blade 2 in which the holder 21 and the annular plate 22 are integrally fixed to the mixture 1 is formed. The blades 23 are fixed to the holder 21 and / or the annular plate 22 by an appropriate method such as welding. A perspective cross-sectional view of the agitating blade 2 is shown in FIG.

[0021] 9(a) shows the flow of fluid F around the agitator 2 rotated by a motor (not shown), and Fig. 9(b) shows the flow inside the agitator 2, in a stirring device in which an agitator 2 is installed inside a stirring tank T containing fluid F. As shown in Fig. 9(a), the fluid F held inside the agitator 2 by the rotation of the motor is forced from the hollow portion 15 toward the outer periphery by centrifugal force and the flow caused by the blade plate 23, and is discharged from the outer periphery of the agitator 2.

[0022] 9(b) shows the flow of fluid F inside the agitator impeller 2, with the general flow shown on the left and the detailed flow shown on the right. In FIG. 9(b), the blades 23 are omitted to make the fluid flow easier to understand. When the fluid F flows from the hollow portion 15 toward the outer periphery, the fluid F is separated into a fluid F1 that flows within the stack 13 in which each of the mixing elements 11 and 12 is stacked one by one, and a fluid F2 that flows through a flow path 16 with low flow resistance between the stack 13, which is separated by a spacer 14 and connects directly from the hollow portion 15 to the outer periphery of the agitator impeller 2. Fluids F1 and F2 then merge at the outer periphery of the agitator impeller 2 to become fluid F, which is then sucked back into the hollow portion 15, forming a circulating flow of fluid F inside the agitator tank T.

[0023] The above describes the flow of the fluid F when it flows from the hollow portion 15 of the agitator impeller 2 to the outer periphery. Of the fluid F, the fluid F1 flowing within the stack 13 first flows into the stack 13 through the small through-holes 123 of the mixing element 12 that open toward the inner periphery of the hollow portion 15, then flows into the small through-holes 113 of the mixing element 11 that communicate with the small through-holes 123, and then flows into the small through-holes 123 of the mixing element 12 that communicate with the small through-holes 113 again. After repeating this flow, the fluid F1 finally flows out of the small through-holes 113 of the mixing element 11 that open on the outer periphery of the stack 13. Then, as the fluid F1 flows from the hollow portion 15 through the communicating small through-holes 113 and 123 inside the stack 13 toward the outer periphery, the fluid F1 is highly mixed by repeatedly undergoing division, merging, reversal, turbulence, vortex flow, collision, etc.

[0024] On the other hand, the upper and lower surfaces of the small through holes 113, 123 of the mixing elements 11, 12 constituting the stack 13 are open and are in contact with the flow path 16 with low flow resistance that connects directly from the hollow portion 15 to the outer periphery of the agitator blade 2, so the fluid F1 flowing inside the stack 13 and the fluid F2 flowing through the flow path 16 are in contact. Because the fluid F2 flows through the flow path 16 with low flow resistance, the kinetic energy of the fluid F2 is greater than the kinetic energy of the fluid F1 flowing inside the stack 13 with high flow resistance. Therefore, a portion of the fluid F1 is pulled by the fluid F2 with high kinetic energy due to the difference in kinetic energy and merges with the fluid F2. Conversely, a portion of the fluid F2 with high kinetic energy flows into the stack 13 and merges with the fluid F1 with low kinetic energy. This action promotes mixing by division and merging of the fluids F1 and F2, and the fluid F as a whole is more highly mixed.

[0025] Furthermore, because the agitator 2 has blade plates 23 provided within the hollow portion 15, the centrifugal force exerted on the fluid F by rotation of the agitator 2 is large, and the flow rate of the fluid F circulating inside the agitator tank T can be increased. Also, the agitator 2 has flow paths 16 formed therein, which have low flow resistance between the stacks 13 separated by spacers 14, so that the fluid F2 flowing through the flow paths 16 has a higher flow rate than the fluid F1 flowing within the stacks 13, which has high flow resistance, thereby increasing the overall circulating flow rate of the fluid F inside the agitator tank T. In this way, the blade plates 23 provided within the hollow portion 15 and the spacers 14 provided between the mixing elements 11 and 12 increase the flow rate of the fluid F circulating inside the agitator tank T, and mixing of the fluid F by the agitator 2 is promoted.

[0026] (Variation 1 of Embodiment 1) In the agitating impeller 2, the small through-holes 113 at the innermost periphery of the mixing element 11 shown in Fig. 2(a) and the small through-holes 123 at the outermost periphery of the mixing element 12 shown in Fig. 2(b) are closed through-holes, but they may be open small through-holes 113a, 123a, like the small through-holes 113a at the innermost periphery of the mixing element 11a shown in Fig. 10(a) and the small through-holes 123a at the outermost periphery of the mixing element 12a shown in Fig. 10(b). By using an agitating impeller (not shown) equipped with such mixing elements 11a, 12a, the flow resistance inside the agitating impeller is reduced, thereby increasing the circulation flow rate of the fluid F inside the agitating tank T and further promoting mixing.

[0027] (Variation 2 of Embodiment 1) With regard to the mixing elements 11a, 12a in the agitating impeller described above (Variation 1 of Embodiment 1), as shown in Figures 11(a) and 11(b), the radial walls 113ar, 123ar of the small through holes 113a, 123a at the innermost periphery may be agitated as an agitating impeller 2A (see Figure 12) having mixing elements 11b, 12b that protrude into the hollow portion 15. By using such agitating impeller 2A that has mixing elements 11b, 12b, the radial walls 113ar, 123ar of some of the small through holes 113a, 123a at the innermost periphery protrude into the hollow portion 15 to form a blade plate portion 25. Therefore, even if the agitating impeller 2A does not have a blade plate 23 arranged in the hollow portion 15, a discharge flow can be generated by the blade plate portion 25, and the circulation flow rate of the fluid F inside the agitating tank T can be increased. Since the blade plate 23 is not disposed inside the hollow portion 15, the manufacturing cost of the agitating blade 2A can be made cheaper than that of the agitating blade 2.

[0028] (Variation 3 of Embodiment 1) Furthermore, in the above-described agitating impeller 2A, instead of the four spacers 14 at the same height in the stacking direction, the agitating impeller 2B may be configured with a linked spacer 14a as shown in FIG. 13(a). The linked spacer 14a is formed by connecting four spacer portions 141 with a substantially cross-shaped linking member 142. By replacing the four spacers 14 at the same height in the agitating impeller 2A with linked spacers 14a, the linking member 142 of the linked spacer 14a fits between the radial walls 113ar and 123ar of the mixing elements 11b and 12b, as shown in FIG. 13(b), forming a blade plate portion 25a. Therefore, the agitating impeller 2B can further increase the circulation flow rate of the fluid F inside the agitating tank T and promote mixing compared to the agitating impeller 2A.

[0029] 14 is an exploded perspective view of an agitator impeller 2C according to embodiment 2. The agitator impeller 2C is the same as the agitator impeller 2 according to embodiment 1 in that a substantially disk-shaped holder 21 is disposed above the mixture 1 and an annular plate 22 is disposed below it, but differs from the agitator impeller 2 in that no blade plate 23 is provided within the hollow portion 15 of the mixture 1.

[0030] Even when such an agitator 2C is installed inside the agitator tank T and rotated by a motor, the fluid F held inside the agitator 2C is forced radially outward by the action of centrifugal force and is discharged from the outer periphery of the agitator 2C. At that time, the fluid F is separated into a fluid F1 flowing inside the stack 13 and a fluid F2 flowing through the flow path 16 with low flow resistance between the stacks 13 separated by the spacer 14. The fluid F1 is mixed as it flows through the small through holes 113, 123 that communicate with the mixing elements 11, 12 that make up the stack 13, and is repeatedly divided and merged with the fluid F2, resulting in a high degree of mixing of the entire fluid F. The fluids F1 and F2 then merge at the outer periphery of the agitator 2C to become fluid F, which circulates inside the agitator tank T and is again sucked into the hollow portion 15.

[0031] Since this type of agitator blade 2C does not have a blade plate 23 in the hollow portion 15 like the agitator blade 2, it has fewer parts and is easier to manufacture, so the manufacturing costs can be lower than those of the agitator blade 2.

[0032] (Variation of Embodiment 2) In the mixer 1 constituting the agitating impeller 2C, as shown in Figure 15, a stack 13a may be formed in which spacers 14 are arranged between the mixing elements 11 and 12 constituting the stack 13 of the agitating impeller 2C, and an agitating impeller 2D may be formed having a mixer 1a composed of the stack 13a. Even in the agitating impeller 2D having such a mixer 1a, the fluid F is repeatedly divided and merged between the mixing elements 11 and 12 via the flow path 16 between the mixing elements 11 and 12, which has low flow resistance, so that the fluid F is highly mixed.

[0033] Such an agitating impeller 2D can reduce the number of mixing elements 11, 12, which are expensive to manufacture, and can use a large number of inexpensive spacers 14, so that the manufacturing cost can be made even cheaper than that of the agitating impeller 2C.

[0034] As described above for the agitating blades according to the first and second embodiments and their modifications, the number and shape of the mixing elements 11, 12 and the spacer 14 may be changed as appropriate. Furthermore, the holder 21 may be a circular plate having only four bolt holes 214 and a central mounting hole 211 without providing a central fan-shaped hole 212, or the number of blade plates 23 disposed in the hollow portion 15 may be increased. Furthermore, non-through positioning locking grooves for positioning the blade plates 23 at their respective opposing positions may be provided on the opposing surfaces of the holder 21 and the annular plate 22, and the blade plates 23 may be positioned and fixed between the holder 21 and the annular plate 22 by fitting the ends of the blade plates 23 into the locking grooves.

[0035] 16 shows a stirrer 3 according to an embodiment of the stirrer. The stirrer 3 is configured by screwing a mixer 1, which is configured by three sets of stacks 13, each of which is made up of one mixing element 11, 12, and three sets of spacers 14, to a base 31 with bolts B. A rod-shaped stirrer M incorporating a magnet or magnetic material is attached to the base 31, so that the stirrer 3 can be placed in a container such as a beaker containing liquid and placed on a magnetic stirrer, and the magnet incorporated in the magnetic stirrer can be rotated to rotate the stirrer and mix the liquid in the container.

[0036] 17 is a cross-sectional view showing a state in which a fluid F flows through a mixer 4 according to an embodiment of the mixer. The mixer 4 includes a substantially cylindrical casing 41, an agitator 42, a rotating shaft 43, and an electric motor M as a drive source. The electric motor M drives the agitator 42 to rotate via the rotating shaft 43, and in this embodiment, is driven to rotate by power supplied from a power supply (not shown). The rotating shaft 43 supports the agitator 42 while connected to the electric motor M. A seal member 44 is disposed at the sliding portion between the casing 41 and the rotating shaft 43 to prevent leakage of the fluid F inside.

[0037] The casing 41 is equipped with an inlet nozzle 41a and an outlet nozzle 41b, and the fluid F is sucked into the mixing device 4 via the inlet nozzle 41a and discharged from the outlet nozzle 41b. The agitator 42 has the same configuration as the agitator blade 2 shown in Figure 4, and is formed from three sets of stacked bodies 13 in which two types of approximately circular mixing elements 11, 12 are stacked one by one, and a plurality of cylindrical spacers 14 arranged between the stacked bodies 13 and between the ends thereof. A substantially disc-shaped holder 21 is disposed on the electric motor M side, and a substantially disc-shaped annular plate 22 is disposed on the opposite side of the holder 21 across the mixer 1, and four blade plates 23 (the blade plate 23 is unclear in Figure 17, so see Figure 4) extending in the stacking direction of the mixing elements 11, 12 are arranged in the hollow portion 15.

[0038] When the agitator 42 is driven to rotate by the electric motor M, the fluid F sucked from the inlet nozzle 41a of the mixing device 4 flows into the hollow portion 15 through the through hole 212 of the holder 21 and the through hole 221 of the annular plate 22 that form the agitator 42. The fluid F then flows into the agitator 42 through the small through hole 123 of the mixing element 12 that opens in the inner periphery of the hollow portion 15. The fluid F that has flowed into the agitator 42 is forced radially outward in the radial direction of the agitator 42 by the action of centrifugal force, and the forced fluid F flows radially from the inner periphery to the outer periphery through the small through holes 113, 123 of the communicating mixing elements 11, 12 inside the agitator 42, and flows outward from the outer periphery of the agitator 42 through the small through hole 113 of the mixing element 11 that opens in the outer periphery.

[0039] When the fluid F flows from the inner periphery to the outer periphery inside the mixer 1 that forms the agitator 42, the fluid F is mixed by repeatedly dividing and merging while flowing through the small through holes 113, 123 of the communicating mixing elements 11, 12, and flows out of the agitator 42 and is discharged from the mixer 4 through the outlet nozzle 41b. Meanwhile, a portion of the fluid F that flows out of the agitator 42 flows again into the hollow portion 15 through the through hole 212 of the holder 21 and the through hole 221 of the annular plate 22, and further flows into the mixer 1 that forms the agitator 42 and flows out from the outer periphery of the mixer 1, thereby circulating inside the mixer 1 of the agitator 42. In FIG. 17, a gap C is provided between the inner periphery of the inlet nozzle 41 a of the casing 41 and the outer periphery of the through-hole 221 of the annular plate 22. However, by increasing the outer diameter of the through-hole 221 of the annular plate 22 or inserting a spacer into the outer periphery of the through-hole 221 to reduce the gap C, the flow rate of the fluid F circulating inside the mixer 4 can be reduced, thereby increasing the pressure of the fluid F discharged from the outlet nozzle 41 b of the mixer 4.

[0040] 18 is a configuration diagram of a fluid mixing system relating to an example of use of the mixer 4. A fluid F is accommodated in the stirring tank T, and is connected to the inlet nozzle 41a of the mixer 4 via a nozzle 451 and a valve 452 disposed at the bottom of the stirring tank T, and the outlet nozzle 41b of the mixer 4 is connected to one end of a circulation line 46 via a valve 461. The other end of the circulation line 46 is open to the top of the stirring tank T, so that all of the fluid F mixed by the mixer 4 is returned to the stirring tank T.

[0041] In the mixing system of the example use, when the electric motor M is driven to rotate the agitator 42 inside the mixer 4, the rotation causes a pumping action to suck in a fluid F from the inlet nozzle 41a. As shown in Figure 17, when the fluid F sucked into the mixer 4 flows through the mixer 1 forming the agitator 42, it is mixed by repeatedly dividing and merging while flowing through the small through-holes 113, 123 of the communicating mixing elements 11, 12, and then discharged from the outlet nozzle 41b of the mixer 4. The fluid F discharged from the outlet nozzle 41b flows through the circulation line 46 and is sent back to the agitator tank T, and is sent again to the mixer 4 via the nozzle 451 at the bottom of the agitator tank T.

[0042] According to the mixing system described above, the fluid F is mixed to a high degree by repeatedly passing through the mixer 4. Such a mixing system allows the fluid F in the mixed tank T to be mixed to a high degree without installing the agitator blade 2 (see FIG. 4, etc.) in the mixed tank T. Furthermore, by adjusting the aperture of the valve 461 of the circulation line 46 disposed on the outlet side of the mixer 4, it is possible to increase or decrease the flow rate of the fluid F circulating inside the mixer 4, thereby adjusting the degree of mixing of the fluid F. Note that when the fluid F is a mixture of liquids with different specific gravities, the agitator blade 2 (see FIG. 4, etc.) or a general agitator blade such as a vane type may be installed inside the mixed tank T to preliminarily mix the fluid F in the mixed tank T.

[0043] (Examples) The results of measurements of the mixing performance of the agitator impeller according to the present invention will be explained in comparison with a comparative example using a blade-type agitator impeller and a laminated agitator impeller without blade plates or spacers. Note that the present invention is not limited to the following examples. 1. Shape of the agitator impeller (1) Agitator impeller used in Example 1 In Example 1, the agitator impeller 2 of embodiment 1 shown in Figure 4 was used. However, instead of four blade plates 23, eight blade plates were arranged at 45-degree intervals in the circumferential direction. The mixer 1 constituting the agitator impeller 2 used was the mixing elements 11 and 12 (two closed small through-holes 113 and 123 and one open small through-hole 113 and 123 arranged in the radial direction) having the structure shown in Figure 2. Each mixing element 11, 12 has an outer diameter of 60 mm, an inner diameter of 28 mm, and a thickness of 2 mm. The mixing element 11 (with a first through-hole 113 on the outer periphery) and the mixing element 12 (with a first through-hole 123 on the inner periphery) were stacked to form a set of stacked bodies 13, and three sets of stacked bodies 13 and 2 mm thick spacers 14 were alternately stacked to form the mixture 1. A 3 mm thick holder 21 was placed on the top of the mixture 1, and a 2 mm thick annular plate 22 was placed on the bottom, which was fixed with bolts B and nuts N to form a stirring blade 2 with a height of 23 mm. Two spacers 14 were placed between the stacked bodies 13, and one was placed between the topmost stack 13 and the holder 21, so that a total of three spacers 14 were used in the height direction of the stirring blade 2. As shown in FIG. 9, a rotating shaft 24 was disposed in the holder 21, and an electric motor (not shown) capable of controlling the rotation speed was connected to the upper end of the rotating shaft 24. The agitation vessel T is made of acrylic and has a flat bottom, an internal height of 251 mm where the liquid is contained, and an internal diameter of 240 mm. At the time of measurement, 8 liters of water was placed in the agitation vessel T, and the liquid height was 177 mm from the bottom. The agitation blade 2 was installed so that its lower surface was 60 mm from the bottom of the agitation vessel T.

[0044] (2) Blade-type agitating impeller used in Comparative Example 1 A perspective view of the blade-type agitating impeller 200 used as a comparative example is shown in Figure 19. The blade-type agitating impeller 200 is a Kai cross impeller equipped with four inclined blades 201, with an outer diameter of 70 mm, a blade width of 13 mm, a blade length of 28 mm, a blade thickness of 1.2 mm, and the blades are inclined at 30° perpendicular to the plane of rotation of the blade.

[0045] (3) The stacked agitator blade used in Comparative Example 2 The stacked agitator blade 210 used as a comparative example is shown in Figure 20 (a) as a side view and in Figure 20 (b) as a perspective cross-sectional schematic view. In the stacked agitator blade 210, five sets of stacked bodies 13 each consisting of mixing elements 11 and 12 are closely stacked without disposing a spacer 14 on the mixer 1 in the agitator blade 2, and no blade plate 23 is disposed in the hollow portion 15. The shapes of the mixing elements 11 and 12, the holder 21, and the annular plate 22 are the same as those of the agitator blade 2 in Example 1, but since a total of 10 2 mm thick mixing elements 11 and 12 are stacked, the height of the agitator blade 210, which is equipped with a 3 mm thick holder 21 and a 2 mm thick annular plate 22, is 25 mm, which is 2 mm higher than the height of the agitator blade 2, 23 mm.

[0046] 2. Dissolution of Polymer Liquid Flocculant Using an Agitator Impeller (1) Example 1 Eight liters of tap water was placed in the agitator tank T, and while the agitator impeller 2 was rotating at 600 rpm, a powdered, poorly soluble polymer flocculant was added. The viscosity of the mixed solution was measured at predetermined intervals, and the progress of the agitation was confirmed by the change in the viscosity of the mixed solution over time. The polymer flocculant used was the anionic polymer electrolyte Zetag (registered trademark) 4145 manufactured by BASF, and 10 g was added per 8 liters of tap water. The water temperature during measurement was 24°C. The viscosity measurement device used was a TVB-10 B-type viscometer manufactured by Toki Sangyo Co., Ltd. For viscosity measurement, the agitator impeller 2 was stopped after stirring for a predetermined time after adding the polymer flocculant, and the mixed solution required for measurement was sampled from the agitator tank T into a beaker to measure the viscosity. After measurement, the sampled mixed solution was returned to the agitator tank T. The viscosity change of the mixed solution obtained by repeating the above procedure is shown in the graph in Figure 21.

[0047] (2) Comparative Example 1 The results of the polymer flocculant dissolution experiment when the blade-type agitator 200 was used instead of the agitator 2 are shown in the graph of Figure 21. The water temperature during the measurement was 24°C, and the other conditions were the same as those in Example 1 except for the agitator blade being changed.

[0048] (3) Comparative Example 2 The results of the polymer flocculant dissolution experiment when the stacked agitator blade 210 was used instead of the agitator blade 2 are shown in the graph of Figure 21. The water temperature during the measurement was 24°C, and the other conditions were the same as those in Example 1 except for the agitator blade being changed.

[0049] (Experimental Results-1) From the graph in Figure 21, it was confirmed that the viscosity of the mixture stirred using the stirring blade 2 used in Example-1 according to the present invention was 77 mPa.S 10 minutes after the start of stirring, reached 82 mPa.S after 20 minutes, and then converged to a nearly constant viscosity, and mixing was completed in about 20 minutes. On the other hand, the viscosity of the mixture stirred using the blade-type stirring blade 200 of Comparative Example-1 was 19 mPa.S 10 minutes after the start of stirring, reached 49 mPa.S after 20 minutes, continued to rise slowly thereafter, reached 69 mPa.S after 50 minutes, and then converged to a nearly constant viscosity, and mixing was completed in about 50 minutes. Furthermore, the viscosity of the mixture stirred using the stacked stirring blade 210 of Comparative Example-2 was 14 mPa.S 10 minutes after the start of stirring, and 34 mPa.S after 20 minutes. The viscosity continued to rise slowly thereafter, reaching 52 mPa.S after 60 minutes, after which it converged to a nearly constant viscosity, and it was confirmed that mixing was completed in about 60 minutes.

[0050] As described above, it was found that in Example 1, which used the agitator blade 2 of Embodiment 1, the viscosity of the mixed solution increased quickly after the start of agitation, and mixing was completed quickly, compared to the blade-type agitator blade 200 of Comparative Example 1 and the stacked agitator blade 210 of Comparative Example 2, which does not have the blade plate 23 and spacer 14. Furthermore, it was found that in Example 1, the viscosity after mixing was completed was also higher than in Comparative Examples 1 and 2, and the degree of mixing at the completion of mixing was also higher. From the above results, it was found that the agitator blade of Embodiment 1 can mix to a high degree of mixing more quickly than the blade-type agitator blade 200 and the stacked agitator blade 210, which does not have the blade plate 23 and spacer 14.

[0051] (4) Example 2 The results of the polymer flocculant dissolution experiment (Example 2) using the agitator blade 2C according to embodiment 2 shown in Figure 14 instead of the agitator blade 2 are shown in the graph of Figure 22, superimposed on the experimental results of Example 1 using the agitator blade 2 according to embodiment 1. The water temperature during measurement was 22°C, and the other conditions, except for the change in the agitator blade, were the same as those in Example 1.

[0052] (5) Example 3 The results of the polymer flocculant dissolution experiment (Example 3) using the impeller 2D according to the modified example of embodiment 2 shown in Figure 15 instead of the impeller 2 are shown in the graph of Figure 22, superimposed on the experimental results using the impeller 2 according to embodiment 1. The water temperature during the measurement was 22°C, and the other conditions, except for the change in the impeller, were the same as those in Example 1.

[0053] 22, it was confirmed that the viscosity of the mixture stirred with the stirring blade 2C of Example 2 was 65 mPa.S 10 minutes after the start of stirring, and reached 87 mPa.S after 15 minutes, converging to a nearly constant viscosity, and mixing was completed in about 15 minutes. Furthermore, the viscosity of the mixture stirred with the stirring blade 2D of Example 3 was 39 mPa.S 10 minutes after the start of stirring, and reached 73 mPa.S after 20 minutes, and continued to rise slowly thereafter, reaching 76 mPa.S after 30 minutes and converging to a nearly constant viscosity, and mixing was completed in about 30 minutes.

[0054] As described above, it was found that the viscosity of the mixture increased quickly after the start of stirring with the agitator impeller 2C of Example 2 and the agitator impeller 2D of Example 3, compared to the blade-type agitator impeller 200 of Comparative Example 1 shown in the graph of Figure 21 and the stacked agitator impeller 210 of Comparative Example 2 that does not have the blade plate 23 and spacer 14, and mixing was completed more quickly than with Comparative Examples 1 and 2. Furthermore, it was found that the viscosity after mixing was completed with the agitator impellers of Examples 1 to 3 was higher than with Comparative Examples 1 and 2, and the degree of mixing at the completion of mixing was also higher. From the above results, it was found that the agitator impeller of Embodiment 2 can mix to a higher degree of mixing more quickly than the blade-type agitator impeller 200 and the stacked agitator impeller 210 that does not have the blade plate 23 and spacer 14.

[0055] The embodiments disclosed above should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above embodiments but by the claims, and includes all modifications and variations within the meaning and scope of the claims.

[0056] The present invention is used in technology for mixing or stirring fluids, and is used, for example, in a mixer that can mix even highly viscous fluids with high efficiency, an agitator blade equipped with the mixer, an agitator, a stirring method, an agitator blade assembly method, an agitator, a mixing device, and a mixing system.

[0057] 1, 1a: mixture, 2, 2A, 2B, 2C, 2D: stirring blades, 3: stirring bar, 4: mixing device, 11, 11a, 11b, 12, 12a, 12b: mixing elements, 13, 13a: stack (of mixing elements), 14: spacer, 14a: connecting spacer, 15: hollow portion (of mixture), 16: flow path, 21: holder, 22: annular plate, 23: blade plate, 24: rotating shaft, 25, 25a: blade plate portion, F, F1, F2: fluid, T: stirring tank

Claims

1. A mixture in which a plurality of mixing elements and spacers arranged between the mixing elements are stacked, wherein the mixing element has one large through hole in approximately the center and a plurality of small through holes arranged circumferentially so as to surround the large through hole, and the mixing elements are arranged such that, in a plan view of the mixing element, some or all of the small through holes partially overlap with the small through holes of adjacent mixing elements, with their positions shifted, and the large through holes of the mixing elements are connected continuously or intermittently in the stacking direction of the mixing elements, forming a hollow section inside the mixture.

2. A stirring impeller comprising the mixture described in claim 1, a holder and an annular plate arranged opposite each other with the mixture sandwiched between them, the annular plate having a through-hole in the approximate center, the through-hole communicating with a hollow portion formed inside the mixture, and the holder attached to a rotating shaft that is driven to rotate.

3. An agitator impeller according to claim 2, wherein the hollow portion of the mixer is provided with a plurality of flat blades extending in the stacking direction of the mixing elements.

4. An agitator impeller as described in claim 2, wherein the radial walls of the mixing elements are continuously or intermittently connected to the hollow portion of the mixture, forming a plurality of flat blade portions extending continuously or intermittently in the stacking direction of the mixing elements.

5. An agitator blade according to any one of claims 2 to 4, wherein the mixing element, holder, and annular plate forming the agitator blade are provided with a plurality of fastening through holes, and the agitator blade is fixed integrally by bolts and nuts arranged in the fastening through holes.

6. A stirring device characterized in that the stirring blade according to any one of claims 2 to 4 is disposed in a fluid in a stirring vessel.

7. A method for stirring a fluid using the stirring impeller described in any one of claims 2 to 4, characterized in that the mixture, due to its own rotation, causes the fluid that has flowed into the mixture from the large through-holes of the mixing element via the through-holes of the annular plate to flow out from the outer periphery of the mixing element via the multiple small through-holes of the mixing element.

8. A method for assembling an agitator blade as described in claim 5, wherein the agitator blade is fixed together by means of inserting bolts into the fastening through holes of the mixing element, holder, and annular plate, as well as the spacer, and by means of tightening the ends of the bolts with nuts.

9. A stirrer in which the mixture according to claim 1 is placed on a base having a magnet or magnetic material.

10. A stirrer according to claim 9, wherein the hollow portion of the mixer is provided with a plurality of flat blades extending in the stacking direction of the mixing elements.

11. A mixing device that continuously mixes fluids within a substantially cylindrical casing using an agitator blade as defined in any one of claims 2 to 4, wherein the casing has a fluid inlet and a fluid outlet, and when the agitator blade is driven to rotate within the casing, fluid sucked in from the fluid inlet provided on the circular end face of the casing flows into the agitator blade, and the fluid discharged from the outer periphery of the agitator blade is discharged from the fluid outlet provided on the cylindrical side face of the casing.

12. A mixing system comprising the mixing device according to claim 11, and comprising a fluid circulation path extending from the discharge port to the suction port of the mixing device.

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