JP2017039075A - Solid-liquid agitation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid-liquid agitation device capable of uniformly agitating solid particles having large specific gravity in comparison with a liquid by eliminating interference to a circulation flow caused by flows from each rotary vane and forming the smoother circulation flow.SOLUTION: In a solid-liquid agitation device 1 constituted by including a vertical cylindrical agitation vessel 2, a rotary shaft 3, a first rotary vane 4 disposed at the lower edge of the rotary shaft 3, a second rotary vane 5 disposed above the first rotary vane 4 and a guide plate 6 in a vertical direction disposed on the inner surface of the agitation vessel 2,: the lower edge of the guide plate 6 is located at an upper side from the upper edge of the first rotary vane 4 and a lower side from the lower edge of the second rotary vane 5; with this constitution, a downward flow caused by the second rotary vane 5 eliminates interference to an upward flow caused along the guide plate 6 and the stream of a circulation flow is made smooth; and then uniform agitation can be realized.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid-liquid stirring apparatus. More specifically, the present invention relates to a solid-liquid stirring apparatus capable of uniformly stirring solid particles having a specific gravity larger than that of a liquid.

  In a stirring device that uniformly stirs a liquid and solid particles, various types of blade shapes are employed depending on the viscosity of the liquid and the like. For example, an anchor blade for forcibly moving the liquid on the wall of the stirring tank, a ribbon blade with a spiral blade, and the like are employed. However, for a liquid having a relatively low viscosity, a method described in Patent Document 1 in which paddle blades are arranged one above the other to generate an axial flow up and down is often employed. This is because uniform stirring can be easily achieved with a simple configuration.

  The configuration described in Patent Document 1 will be described. The stirrer described in Patent Document 1 is provided with a rotating shaft at the center of a stirring tank on a vertical cylinder, a plurality of rotating blades on the top and bottom, and a vertical baffle plate on the inner surface of the stirring tank. It is configured. In this stirrer, the flow from the radially inner side to the outer side is caused by the rotary blades. A plurality of baffle plates form a circulation flow with the flow along the inner circumferential direction of the stirring tank as an up and down flow. Uniform agitation can be realized by this circulating flow flowing smoothly without being influenced by other flows.

  However, compared to the case of stirring to ensure a certain degree of uniformity, as in the case of slurry preparation, in the case of stirring to perform a reaction for growing solid particles by agglomeration, etc. However, more uniform stirring is required. In addition, as a result of the development of computers, more detailed states of the distribution of solid particles in the stirring device can be calculated. As a result, if the specific gravity of the solid particles is larger than the specific gravity of the liquid, each paddle It was found that the influence of the flow interference generated by the blades was increased, and a smooth circulation flow could not be formed, and uniform stirring could not be achieved.

JP-A-5-49890

  In view of the above circumstances, the present invention uniformly stirs solid particles having a higher specific gravity than liquid by reducing interference with the circulation flow caused by the flow from each paddle blade and forming a smoother circulation flow. It is an object of the present invention to provide a solid-liquid stirring device that can be used.

The solid-liquid stirring apparatus of the first invention includes a vertical cylindrical stirring tank, a rotating shaft suspended from the upper center of the stirring tank, a first rotating blade provided at the lower end of the rotating shaft, A solid-liquid structure including a second rotating blade provided above the first rotating blade and causing a downward flow, and a vertical guide plate provided on the inner surface of the stirring tank. The stirring device is characterized in that the lower edge of the guide plate is provided above the upper edge of the first rotary blade and below the lower edge of the second rotary blade.
The solid-liquid stirring apparatus of the second invention is characterized in that, in the first invention, the first rotary blade causes a flow to the side.
In the solid-liquid stirring device of the third invention, in the first invention or the second invention, one or more upper rotor blades are further provided above the second rotor blades, and all these upper rotor blades are directed downward. It is characterized by producing a flow of
In any one of the first to third inventions, the solid-liquid stirring device of the fourth invention is such that the distance from the rotation center of the second rotary blade to the tip of the second rotary blade is 1/10 of the inner diameter of the stirring tank. It is characterized by being 1/6 or less.
In any one of the first to fourth inventions, the solid-liquid stirring device of the fifth invention is H between the upper edge of the first rotor blade and the lower edge of the second rotor blade, When h is between the upper edge and the lower edge of the guide plate, h / H is 1/4 to 3/4.

According to the first aspect of the invention, the agitation tank is provided with the first rotary blade provided at the lower end of the rotation shaft, the second rotary blade that generates a downward flow, and the upper and lower surfaces provided on the inner surface of the stirring tank. Direction guide plate, and the lower edge of the guide plate is located above the upper edge of the first rotor blade and below the lower edge of the second rotor blade. As a result, the downward flow generated by the second rotor blade is less likely to interfere with the upward flow generated along the guide plate, and the flow of the circulating flow becomes smooth. Thereby, uniform stirring can be realized.
According to the second aspect of the invention, the first rotor blades cause the flow to the side, so that the solid particles settled at the bottom of the stirring tank are placed on the circulation flow without interfering with the smooth circulation flow. be able to. Thereby, more uniform stirring can be realized.
According to the third invention, one or more upper rotor blades are provided above the second rotor blades, and all of these upper rotor blades generate a downward flow, so that Even when the upper and lower lengths become longer and one or more upper rotor blades are provided, a smooth circulating flow can be realized. Therefore, uniform stirring is possible.
According to the fourth invention, when the distance from the rotation center of the second rotary blade to the tip of the second rotary blade is 1/10 or more and 1/6 or less of the inner diameter of the stirring tank, A sufficient flow is generated in the liquid, and the flow is less likely to interfere with the circulating flow, thereby realizing a smoother circulating flow. Therefore, more uniform stirring is possible.
According to the fifth aspect of the invention, the distance between the upper edge of the first rotor blade and the lower edge of the second rotor blade is H, and the distance between the upper edge of the first rotor blade and the lower edge of the guide plate is h. When h / H is not less than 1/4 and not more than 3/4, the downward flow generated by the second rotor blade is less likely to interfere with the upward flow generated along the baffle plate. , The flow of the circulation flow becomes smoother. Thereby, more uniform stirring can be realized.

It is a section front view of the solid-liquid stirring apparatus concerning the embodiment of the present invention. It is a cross-sectional top view of the solid-liquid stirring apparatus of FIG. It is explanatory drawing of the circulation flow of Example 1 in the solid-liquid stirring apparatus of FIG. It is explanatory drawing of the simulation result of Example 1 in the solid-liquid stirring apparatus of FIG. It is explanatory drawing of the circulation flow of the comparative example 2 in the solid-liquid stirring apparatus of FIG. It is explanatory drawing of the comparative example 2 simulation result in the solid-liquid stirring apparatus of FIG.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front sectional view of a solid-liquid stirring apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a sectional view of the solid-liquid stirring apparatus 1 of FIG.

  A solid-liquid stirring apparatus 1 according to this embodiment includes a vertical cylindrical stirring tank 2. The axial center of the cylindrical portion of the stirring tank 2 is oriented in the vertical direction, and a bottom portion is provided at the lower end of the cylindrical portion, and a lid portion (not shown) is provided at the upper end. The agitation tank 2 is made of a material that does not react with internal liquids and solids, such as stainless steel.

  The solid-liquid stirring apparatus 1 includes a rotating shaft 3 at the center of the stirring tank 2, that is, on the cylindrical axis of the stirring tank 2. The rotating shaft 3 is installed on the lid, and hangs from the lid toward the bottom of the agitation tank 2. The rotating shaft 3 is rotated at a speed of about several hundreds of RPM via a speed reducer or the like by a rotation driving source (not shown) such as a three-phase induction motor installed outside the stirring tank 2. The rotation direction is determined by the twist direction of the blades constituting the rotor blade described later, but in this embodiment, it rotates in the direction indicated by the arrow in FIG.

  A first rotary blade 4 fixed to the rotary shaft 3 is provided at the lower end of the rotary shaft 3. The first rotating blade 4 rotates on the spot as the rotating shaft 3 rotates, and causes the liquid in the stirring tank 2 to flow. The first rotary blade 4 is a so-called turbine blade formed of a disk-like portion 4a and a flat plate-like blade portion 4b. The first rotary blade 4 sucks liquid from the axial direction and is side of the rotary shaft 3, that is, the radius of the stirring tank 2. A flow toward the outside in the direction is generated. The center of the disk-like portion 4 a is disposed on the axis of the rotation shaft 3. The flat plate surfaces of the six flat blade portions 4b, that is, the surfaces that receive the resistance of the liquid are configured to be perpendicular to the flat plate surface of the disk-shaped portion 4a. In the first rotary blade 4, the distance from the rotation center of the first rotary blade 4 to the tip of the blade portion constituting the first rotary blade 4 is 1/6 of the inner diameter of the stirring tank 2.

  By causing the first rotary blade 4 to generate a lateral flow, the solid particles that have settled at the bottom of the stirring tank 2 can be placed on the circulating flow without interfering with the smooth circulating flow. Thereby, more uniform stirring can be realized.

  The rotary shaft 3 is provided with a second rotary blade 5 above the first rotary blade 4. The second rotary blade 5 is also fixed to the rotary shaft 3 like the first rotary blade 4, and rotates on the spot when the rotary shaft 3 rotates, so that the liquid in the agitation tank 2 changes from above to below. Create a flow towards. The second rotary blade 5 is composed of four flat plates 5 a, and the four flat plates 5 a are provided such that the longitudinal direction of the flat plate 5 a coincides with the radial direction of the rotary shaft 3. Further, the short sides of the four flat plates 5a are inclined with respect to the axis of the rotary shaft 3 by a predetermined angle as shown in FIG. In this embodiment, this angle is 45 degrees. Due to this angle, when the second rotary blade 5 rotates, a flow is generated from above to below.

  In the second rotary blade 5, the distance from the rotation center of the second rotary blade 5 to the tip of the flat plate 5 a constituting the second rotary blade 5 is 1/10 or more and 1/6 or less of the inner diameter of the stirring tank 2. That is, the distance from the tip of one flat plate constituting the second rotary blade 5 to the tip of the other flat plate at the point target position with the rotational center of the second rotary blade 5 as the center of symmetry is the inner diameter of the stirring vessel 2. 1/5 or more and 1/3 or less.

  When the distance from the rotation center of the second rotary blade 5 to the tip of the blade portion of the second rotary blade 5 is 1/10 or more and 1/6 or less of the inner diameter of the stirring tank 2, the second rotary blade 5 A sufficient flow is generated in the liquid, and the flow is less likely to interfere with the circulating flow, thereby realizing a smoother circulating flow. Therefore, more uniform stirring is possible.

  In addition, although the solid-liquid stirring apparatus 1 of this embodiment demonstrated the form which has the 2 rotary blades of the 1st rotary blade 4 and the 2nd rotary blade 5 in the rotating shaft 3, the axial direction of the stirring tank 2 is demonstrated. When the length of is long, it may be configured to have three or more rotor blades. That is, an upper rotor blade is provided above the second rotor blade 5 so that a downward flow is generated for all upper rotor blades. The upper rotor blade may have the same configuration as the second rotor blade.

  One or more upper rotor blades are provided above the second rotor blades, and when all these upper rotor blades generate a downward flow, the upper and lower lengths of the agitation tank become longer, and one or more rotor blades are provided. Even when the upper rotor blade is provided, a smooth circulating flow can be realized. Therefore, uniform stirring is possible.

  Four guide plates 6 are equally provided in the circumferential direction on the inner surface of the stirring tank 2. The short side direction of the guide plate 6 is provided along the radial direction of the stirring tank 2, and the length of one guide plate 6 in this direction is determined in consideration of the complete baffle plate condition. 1/10 of the inner diameter. The longitudinal direction of the guide plate 6 is provided in parallel with the axial direction of the stirring tank 2. The upper edge of the guide plate 6 is made higher than the upper surface of the liquid when a predetermined amount of liquid and solid corresponding to the solid-liquid stirring device 1 is introduced. The lower edge of the guide plate 6 is positioned at the following location. That is, the lower edge of the guide plate 6 is provided above the upper edge of the first rotary blade 4 and below the lower edge of the second rotary blade. More preferably, the distance between the upper edge of the first rotor blade 4 and the lower edge of the second rotor blade 5 is H, and the distance between the upper edge of the first rotor blade 4 and the lower edge of the guide plate 6 is h. In this case, h / H is set to 1/4 or more and 3/4 or less.

  The lower edge of the guide plate 6 of the agitation tank 2 is provided above the upper edge of the first rotary blade and below the lower edge of the second rotary blade. The generated downward flow is less likely to interfere with the upward flow generated along the guide plate 6, and the flow of the circulating flow becomes smooth. Thereby, uniform stirring can be realized.

  Further, H is defined between the upper edge of the first rotor blade 4 and the lower edge of the second rotor blade 5, and h is defined between the upper edge of the first rotor blade 4 and the lower edge of the guide plate 6. Sometimes, h / H is not less than 1/4 and not more than 3/4, so that the downward flow generated by the second rotary blade 5 is less likely to interfere with the upward flow generated along the guide plate 6. And the flow of the circulating flow becomes smoother. Thereby, more uniform stirring can be realized.

  In particular, when the ratio of the specific gravity of the solid particles to the liquid is large, the force that the solid particles try to settle is strong, and when the specific gravity of the liquid: specific gravity of the solid particles is 1: 5 to 1:10, When the lower end is not at a position where h / H = 1/4 to 3/4, that is, when the lower end of the guide plate 6 is h / H <1/4, the first rotor blade 3 is moved outward. The flow collides with the guide plate 6 at an early stage, and a flow that interferes with the circulation flow is likely to occur, and the flow of the circulation flow is disturbed. When h / H> 3/4, the strength of the flow in the upward direction by the guide plate 6 is not obtained, and the flow of the circulating flow is disturbed.

(Example)
About the solid-liquid stirring apparatus 1 which concerns on this embodiment, the effect of the structure of this embodiment was confirmed by fluid analysis simulation.
As an analysis model, a first rotating blade 4 that is a disk turbine blade and a second rotating blade 5 that is an inclined paddle blade are provided for a stirring tank 2 having an inner diameter of 50 cm and an inner surface height of 50 cm. The distance from the tip of the blade portion 4b of the first rotor blade 4 to the rotation center of the first rotor blade 4 and the distance from the tip of the second rotor blade 5 to the center of rotation of the second rotor blade 5 are both 10 cm. The distance between the first rotor blade 4 and the second rotor blade 5 was 14 cm. The number of rotations of the rotating shaft is 400 RPM. The length of the induction plate 6 in the radial direction of the stirring tank 2 was 5 cm. The ratio of the specific gravity of the liquid to be stirred in the stirring tank 2 and the solid particles was 1: 9. The diameter of the solid particles was set to 100 μm, and analysis was performed by changing the value of h / H, and the state of the flow inside the stirring tank 2 and the distribution of the solid particles were confirmed.

  Further, when the flow of the circulating flow is smooth and the solid particles are appropriately wound up, the density of the solid particles in the vicinity of the guide plate 6 and above the second rotary blade 5 is increased. The solid particle concentration was extracted in step (1), and whether or not the flow of the circulating flow was sufficiently smooth was determined by whether or not the value obtained by dividing the solid particle concentration in that portion by the average concentration exceeded 1. The concentration is the mass of solid particles in the liquid per unit volume, and the average concentration is the solid particles per unit volume of the liquid when the solid particles are ideally diffused in the liquid in the stirring tank 2. Is the mass.

  The analysis results are shown in Table 1. In Comparative Examples 1 and 2 where the value of h / H is less than 1/4, it can be seen that the concentration of the solid particles is lower than the average concentration, and the solid particles are not sufficiently rolled up. Also in Comparative Example 3 in which the value of h / H is larger than 3/4, the concentration of solid particles is lower than the average concentration, and the solid particles are not sufficiently rolled up. In Examples 1 to 3 in which the value of h / H is 1/4 or more and 3/4 or less, the concentration of solid particles exceeds the average concentration, and a smooth circulation flow is formed, and the solid particles are sufficiently wound up. I understand that.

  FIGS. 3 to 6 show the results of analysis in Example 1 and Comparative Example 2 and the state of the circulating flow under the conditions. FIG. 3 is an explanatory diagram of the circulation flow in Example 1, FIG. 4 is a simulation result in Example 1, FIG. 4 (A) shows the density of the solid particle concentration, and FIG. The flow state at that time is shown. FIG. 5 is an explanatory diagram of the circulating flow in Comparative Example 2, FIG. 6 is a simulation result in Comparative Example 2, and FIG. 6 (A) shows the density of solid particle concentration, FIG. 6 (B). Indicates the state of the flow at that time.

  Comparing FIG. 4 (A) and FIG. 6 (A), it can be seen that particularly in the right guide plate 6, a dark region having a high solid particle concentration extends above the guide plate 6. Moreover, when FIG. 4 (B) and FIG. 6 (B) are compared, in FIG. 4, a smooth flow line can be confirmed from the lower right of the stirring tank 2 toward the left and right center of the stirring tank 2. In FIG. 6, the smooth flow line up and down seen in FIG. 4 could not be confirmed. That is, in Example 1, as shown in FIG. 3, the downward flow obtained by the rotor blades 4 and 5 is changed to the upward flow along the guide plate 6 so that a smooth circulation flow is formed. On the other hand, in Comparative Example 2, as shown in FIG. 5, the flow discharged in the radial direction of the stirring tank 2 by the first rotating blade 4 collides with the guide plate 6 relatively quickly, and from there, the flow of the stirring tank 2 The flow is directed toward the shaft center, and a smooth flow cannot be formed by colliding with the flow from the second rotary blade 5.

DESCRIPTION OF SYMBOLS 1 Solid-liquid stirring apparatus 2 Stirrer tank 3 Rotating shaft 4 1st rotary blade 5 2nd rotary blade 6 Guide plate

Claims (5)

A vertical cylindrical stirring tank;
A rotating shaft hanging from above the center of the stirring tank;
A first rotary blade provided at the lower end of the rotary shaft;
A second rotor blade provided above the first rotor blade and causing a downward flow;
A solid-liquid stirring device configured to include a vertical guide plate provided on the inner surface of the stirring tank,
A lower edge of the guide plate is provided above the upper edge of the first rotor blade and below the lower edge of the second rotor blade;
A solid-liquid stirring device. The first rotor blades cause a lateral flow;
The solid-liquid stirring apparatus according to claim 1. One or more upper rotor blades are further provided above the second rotor blades,
All these upper rotor blades are causing downward flow,
The solid-liquid stirring apparatus according to claim 1 or 2, characterized by the above. The distance from the rotation center of the second rotary blade to the tip of the second rotary blade is:
1/10 or more and 1/6 or less of the inner diameter of the stirring tank,
The solid-liquid stirring apparatus according to any one of claims 1 to 3, wherein the solid-liquid stirring apparatus is characterized. H between the upper edge of the first rotor blade and the lower edge of the second rotor blade,
When h is between the upper edge of the first rotor blade and the lower edge of the guide plate,
h / H is not less than 1/4 and not more than 3/4.
The solid-liquid stirring apparatus according to any one of claims 1 to 4, wherein the solid-liquid stirring apparatus is characterized.