JP2003200030A - Agitation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agitating blade which prevents the residence of powder having low specific gravity and a fluid having a wide viscosity range of low viscosity to high viscosity, improves the involvement of the powder in the fluid and the solid-liquid mixing performance and prevents the attachment of the powder to an agitating shaft when the powder is mixed in the fluid. <P>SOLUTION: This agitation apparatus comprises a broad paddle blade 3 arranged at the bottom of an agitating tank 1 and an H-type paddle blade 4 arranged in the upper part of the blade 3. The blade 4 is arranged so that the blade 4 precedes the blade 3 adjacent to the blade 4 vertically at 0-90° crossing angle in the rotational direction and the blades 3 and 4 are superimposed on each other in the agitating shaft direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to liquid-liquid mixing, gas-liquid mixing in a wide range of stirring operations in a laminar flow region to a turbulent flow region.
Liquid mixing, solid-liquid mixing, gas-liquid-solid mixing, liquid-liquid / gas-liquid / solid-liquid / gas-liquid-solid reaction and distillation / concentration, crystallization, dissolution, suspension, dispersion, etc. The present invention relates to a stirrer for efficiently performing the above operation.

[0002]

2. Description of the Related Art In a conventional stirring operation, a stirring blade type is selectively used depending on the viscosity of a fluid to be stirred.
It is common to use small blades such as turbine blades and paddle blades in multiple stages for stirring low-viscosity fluid, and large blades such as anchor blades and helical ribbon blades are generally used for stirring high-viscosity fluid. It has become a target.

Further, in recent years, large paddle blades capable of performing efficient stirring in a wide viscosity range from low viscosity to high viscosity have been developed by various domestic agitator manufacturers (Japanese Patent Laid-Open No. Sho 61-61). -200842, JP 4-9
0839, JP-A-5-49890, JP-A-7-12
4456, JP-A-9-75699, JP-A-10-2
Nos. 4230 and Jiukaihei 07-34928).

However, these stirring blades are mainly focused on the liquid-liquid system stirring and mixing, and the operability in mixing the powder with the liquid is hardly considered. Small multi-stage blades such as turbine blades and paddle blades lack mixing ability of medium and high viscosity fluids, which makes mixing powders into medium and high viscosity fluids difficult. In addition, the old large blades such as anchor blades and helical ribbon blades lack the mixing properties of low-viscosity fluids.
Large paddle blades developed in recent years also have problems such as adhesion and scattering of powder on the stirring blade, stirring shaft, and inner wall of the stirring tank.

For example, in Japanese Unexamined Patent Publication No. 10-24230, a paddle blade made of a wide flat plate disposed at the bottom of a stirring tank is attached to the lowermost stage, and comb-shaped blades are attached to the middle and upper stages, and the lowermost stage. The adjacent paddle blades in the middle stage, which are adjacent to the paddle blades located in the vertical direction, are arranged at an intersection angle of less than 90 degrees in advance in the rotational direction, and are adjacent to the paddle blades in the lowermost stage. The middle-stage comb-shaped wing has an axial overlap, and the cross-angle of the upper-stage comb-shaped wing adjacent to the middle-stage comb-shaped wing is less than 90 degrees. Disclosed is a stirring device in which the middle comb blade and the upper comb blade that is adjacent to the upper comb blade overlap each other in the axial direction.

According to the above stirring blade, the discharge flow generated by the wide paddle blade installed in the lowermost stage and the discharge flow generated by the comb-shaped blades installed in the middle and upper stages are less likely to interfere with each other, resulting in a low viscosity. It becomes possible to efficiently mix liquids of high to high viscosity with low required power.

However, the discharge flow (the flow from the center of the stirring tank toward the tank wall) generated by the comb-shaped stirring blades installed in the upper stage interferes with the flow from the tank wall near the liquid surface toward the center of the stirring tank. For this reason, when the powder is added to the liquid being stirred, the powder is unlikely to move to the center of the stirring tank, and the powder is less likely to be drawn into the liquid due to the downward flow near the stirring shaft. It stays on the surface of the liquid forever and deteriorates the mixing property of the powder into the liquid. Further, when the amount of the fluid to be stirred is small, there is a problem that the powder introduced into the upper and middle comb blades adheres. Further, the comb blades in the upper and middle stages scatter the powder, causing a problem that the powder adheres to the inner wall surface of the tank.

Further, in the agitator disclosed in Japanese Patent Laid-Open No. 4-90839, a radial flow type tank bottom blade and a gate type blade having a vertical blade on a strip plate in the upper portion thereof are arranged in a rotating direction with respect to each other. They are arranged so that their phases are shifted and they overlap each other in the vertical direction. In this agitator, since the tank bottom blade having a size large enough to form a circulating flow over the entire tank is not installed, the circulating flow over the entire tank is insufficiently formed, and the gate-shaped blade is Due to the action of the strong discharge flow generated, not only the local circulation flow generated at the upper end of the tank bottom blade is hindered but also the upward flow is hindered, and as a result, poor mixing is likely to occur. Furthermore, the above-mentioned JP-A-1
Similar to the stirrer described in Japanese Unexamined Patent Publication No. 0-24230, there are problems that the powder stays on the liquid surface, the powder adheres to the portal blade / stirring shaft, and the powder is scattered by the portal blade. ing.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a powder / liquid even when a powder having a low specific gravity is mixed with a fluid having a wide viscosity range from low viscosity to high viscosity, particularly from medium viscosity to high viscosity. To prevent stagnation of powder,
An object of the present invention is to provide a stirring blade that improves liquid mixing properties and prevents powder from adhering to a stirring shaft and a stirring layer wall.

[0010]

As a result of intensive studies to solve the above problems, the present inventor has arranged a wide paddle blade on a stirring shaft provided at the center of the stirring tank so as to be close to the bottom of the tank. 1 on the stirring shaft above the wide paddle blade.
The H-shaped paddle blades having a number of stages or more are arranged, and the H-shaped paddle blades are 0 to 90 more than the stirring blades in the lower stage vertically adjacent to the rotation direction.
The inventors have found that it is possible to efficiently stir the fluid by advancing at a crossing angle of ° and partially overlapping the stirring blades vertically adjacent to each other, and completed the present invention.

That is, according to the present invention, a stirring shaft is provided in the central portion of a vertical cylindrical stirring device, a wide paddle blade is arranged on the stirring shaft so as to be close to the bottom of the tank, and the stirring shaft above the wide paddle blade is further provided. One or more stages of H-shaped paddle blades are arranged on the upper side, and the H-type paddle blades are made to precede the lower stirring blades vertically adjacent to the rotation direction by a crossing angle of 0 to 90 °, and are vertically adjacent. The present invention provides a stirring device characterized in that a part of the stirring blade has an overlap.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of a stirring device according to the present invention. A stirring device comprising a wide paddle blade 3 arranged on the stirring shaft 2 on the bottom of the stirring tank 1 and an H-shaped paddle blade 4 arranged on the same stirring shaft on the upper portion thereof. The wide paddle blade 3 has a lower end. The portion is arranged at the bottom of the tank close to the bottom wall surface of the stirring tank, the blade tips are recessed with respect to the rotational direction, and the structure has a recess at the center of the upper end.

It is preferable that the wide paddle blade 3 has a shape large enough to form a circulating flow over the entire tank even for medium-high viscosity fluids. / D) is preferably in the range of 0.6 to 0.8 (eg 0.77 in FIG.
Is 0.6).

Further, the ratio (h / L) of the blade height of the wide paddle blade 3 to the straight body length of the tank is preferably in the range of 0.2 to 0.5. Generally, the blade height is relative to the tank inner diameter. It is often expressed as a ratio. According to this expression, the ratio of blade height to tank inner diameter (h / D) is 0.3.
To 0.5 (for example, in FIG. 1, h / D = 0.
3 and 0.45 in FIG. 2).

The H-shaped paddle blade 4 is used in one stage or a plurality of stages depending on the situation, but in the present embodiment, the case where one stage of the H-shaped paddle blade 4 is used is shown. When the H-shaped paddle blade 4 is a single stage, the H-shaped paddle blade 4 is arranged in front of the wide paddle blade 3 installed at the bottom of the tank at an intersection angle of 0 to 90 °, more preferably 30 to 60 ° with respect to the rotation direction. Moreover, the wide paddle blade 3 and the H-shaped paddle blade 4 have an overlap in the axial direction.

Further, as an agitator having a positional relationship among the above-mentioned members, another embodiment as shown in FIG.
As shown in FIG. 3, the H-shaped paddle blade 4 may be modified so that the H-shaped paddle blades are connected to each other to secure the strength of the blade.

Further, as shown in FIG. 4, when a plurality of stages of H-type paddle blades are used (in FIG. 4, H-type paddle blades 4
And two-stage use of the H-shaped paddle blade 4 ′), and the upper H-paddle blade 4 ′ is 0 to 90 ° with respect to the rotation direction than the lower H-paddle blade 4 is preferably 30 to 60. The leading H-shaped paddle blades 4 are arranged ahead of the wide paddle blades 3 while being arranged in advance at a crossing angle in the range of 0 ° and having an axial overlap with vertically adjacent stirring blades. They are arranged in advance with a crossing angle in the range of 0 to 90 °, preferably 30 to 60 ° with respect to the direction.

In this case, it is preferable to select the crossing angle of each blade so that the rotating shaft rotates in a well-balanced manner. For example, when two H-shaped paddle blades are used as shown in FIG. The lower paddle blade 4 ′ with the lower paddle blade 4 ′ at the crossing angle of 45 °.
May be arranged at an intersection angle of 45 ° ahead of the wide paddle blade 3.

The H-shaped paddle blade 4 or 4'has a radius of a blade diameter.
Axial length (wing height: 1/2 of blade span ds)
hs) is preferably longer, and considering the dimensional restrictions of the stirrer and the use of multiple stages of H-shaped paddle blades, the range may be 1/2 · ds ≦ hs ≦ 4 · ds. preferable. The blade span generally refers to the widest part of the blade. Further, it is preferable that the vertically long blade extending in the vertical direction of the stirring shaft at the blade tip portion is parallel to the stirring shaft or has a slight angle.

The H-shaped paddle blade and the wide paddle blade may have various shapes as shown in FIG. That is, the H-shaped paddle blade may be a complete H-shaped, a substantially C-shaped, or a tapered H-shaped.

The vertical blade at the tip of the H-shaped paddle blade with respect to the width direction is 0 ° (parallel to the axis) ≦ θ ≦ 30 °, where θ is the angle between the vertical side and the stirring axis. The range is preferable, and when the widths of the vertically long blades are not parallel, it is preferable that 0 ° ≦ θin (angle of inner side) ≦ θout (angle of outer side) ≦ 30 °.

Blade diameter of H-shaped paddle blade (blade span: ds)
Is preferably smaller than the blade diameter (blade span: d) of the wide paddle blade installed at the lowermost stage, and 1/3 · d ≦ d
The range of s ≦ 3/4 · d is particularly preferable.

Furthermore, when the stirring efficiency is taken into consideration, the distance between the stirring shaft and the vertical side (inner side) adjacent to the stirring shaft of the longitudinal blade at the tip of the H-shaped paddle blade is the stirring tank. The inner diameter D is preferably 2% or more, and preferably 15% or less.

Further, the paddle part for supporting the vertically long blade is
It may be inclined so as to generate a downward flow near the stirring shaft.
Furthermore, the fluid swirls on the inner wall of the stirring tank (so-called circulation).
You may install the rectification | straightening means 5 (jamming board) which inhibits.
As the rectifying means 5, a flat plate-shaped member having a width of about 2 to 15% of the stirring tank inner diameter D or a round bar-shaped member can be used.

The stirring device according to the present invention has a viscosity of 2
-20 Pa · s, particularly preferably a viscosity of 5-15 Pa · s
This is an apparatus suitable for mixing powder into the liquid of s. In addition, from the viewpoint of preventing scattering of powder and liquid, and economical viewpoints such as motor capacity and power consumption, the stirring power as an operating condition is
0.3-6.0 kWm ^-3 , especially 1.0-2.0 kWm
^-3 is preferable.

Next, the movement of the fluid when the powder is put into the liquid will be described with reference to FIG. The powder charged in the stirring tank flows along with the liquid while floating on the liquid surface, and draws a spiral on the liquid surface to be drawn to the vicinity of the stirring shaft.

A downflow is generated near the stirring shaft, and the powder is drawn into the liquid by this downflow. At this time, the powder is drawn into the liquid along the agitation shaft, but is not drawn in close contact with the agitation shaft, and is kept a little distance from the agitation shaft. With a spread across the inner side, it is drawn in a spiral. For this reason, most of the powder is drawn into the liquid without coming into contact with the stirring shaft, and the adhesion of the powder to the stirring shaft can be reduced.

When the powder drawn into the liquid moves to the vicinity of the upper end of the wide paddle blade installed at the bottom of the stirring tank while drawing a spiral along the stirring shaft without contacting the stirring shaft,
It passes through a recess at the center of the upper end of the wide paddle blade, is drawn into the most negative pressure portion on the back side with respect to the rotating direction of the wide paddle blade, and is further discharged toward the wall surface of the stirring tank by the discharge flow generated by the wide paddle blade.

The powder discharged together with the liquid toward the wall surface of the stirring tank by the wide paddle blades is converted to an upward flow of the liquid and rises along the wall surface to the upper portion of the stirring tank.
Further, the flow of the liquid is converted toward the center of the stirring tank in the vicinity of the liquid surface, and circulates to the center of the stirring tank.

In addition to such a large circulation flow in the vertical direction over the entire stirring tank, the horizontal discharge flow generated by the H-shaped paddle blades and the sheared mixing of the H-shaped paddle blades and the wide paddle blades are used to add the powder introduced. The body is evenly dispersed in the liquid.

In the stirring apparatus of the present invention, the wide paddle blade installed at the bottom of the lowermost tank acts as a main stirring blade, and the H-shaped paddle blade installed at the upper stage of the wide paddle blade acts as an auxiliary blade.

The wide paddle blades, which are the main blades, generate a large vertical circulation flow over the entire area of the stirring tank. When the wide paddle blades rotate in the fluid, positive pressure is always generated on the front surface and negative pressure is generated on the back surface with respect to the rotation direction. On the surface on the front side of the wide paddle blade, the fluid is pushed out in the rotation direction of the blade and discharged toward the wall surface of the stirring tank under the influence of centrifugal force.

Further, due to the influence of the positive pressure generated on the front surface of the blade, the fluid is also pushed out in the vertical direction, which causes the fluid to wrap around from the upper and lower edges of the blade toward the negative pressure portion on the back side of the blade. At this time, since the wide paddle blades are installed so as to be in sliding contact with the bottom wall surface of the stirring tank,
The fluid wraparound from the blade lower end to the blade back side is smaller than the fluid wraparound from the blade upper end to the blade back side.

In the negative pressure portion on the back surface of the blade, in addition to the wraparound of the fluid from the upper and lower ends of the blade, the drawing of the fluid to the negative pressure portion near the back surface of the blade from the rear in the rotational direction occurs. The fluids drawn toward the upper and lower ends and the negative pressure portion at the rear of the blade merge near the back surface of the blade and are discharged toward the wall surface of the stirring tank by the action of centrifugal force.

That is, most of the discharge flow produced by the wide paddle blade installed at the bottom of the tank is produced by the negative pressure on the back side of the blade. Also, the horizontal swirling flow of the fluid generated by the rotation of the wide paddle blade is not considered to be generated by the blade pushing the fluid in the rotation direction, but rather the fluid is rotated by the negative pressure near the back surface of the blade. It can be considered that it is caused by pulling into the department.

Further, even if attention is paid only to the negative pressure portion on the back side of the wide paddle blade, it is considered that a pressure gradient is generated there. That is, it can be said that the negative pressure is closer to the vicinity of the blade tip near the stirring shaft and near the blade tip. Therefore, it is considered that the confluence of the flows in the negative pressure portion due to the wraparound and the drawing of the fluid becomes the highest near the blade tip. Therefore, in order to allow more fluid to flow into the tip on the back side of the blade and to efficiently combine the flows, a recess should be provided near the axis of the upper edge of the wide paddle blade to increase the wraparound of the fluid from the upper edge of the blade. Is particularly preferable.

When the state in which many streams join together is expressed by the term "state in which streamlines are dense", many streams merge in a state in which streamlines are dense, resulting in one large stream.
(A main stream is likened to a river), and this flow forms the circulating flow over the entire stirring tank. The direction of this main stream is affected by the fact that the wraparound of the fluid from the upper end of the blade is larger than the wraparound from the lower end, as described above,
It is slightly downward from the horizontal in the wall surface of the stirring tank. Most of the fluid discharged from the tip of the blade is converted into an ascending flow along the wall surface in the vicinity of the wall surface of the stirring tank, and rises along the wall surface to near the liquid surface. Near the liquid surface, the fluid changes its flow direction toward the center of the stirring tank, and is converted into a downward flow by the influence of the vortex generated near the stirring shaft.

The H-shaped paddle blade as the auxiliary blade plays a role of guiding more fluid to the negative pressure portion on the back side of the wide paddle blade which is the main blade. Like the wide paddle blade, the H-shaped paddle blade also produces positive pressure on the front surface and negative pressure on the rear surface in the rotational direction. Therefore, even at the lower end of the H-shaped paddle blade adjacent to the wide paddle blade, the fluid wraps around from the blade front surface to the blade rear surface.
Due to this wraparound effect, the fluid in the vicinity of the lower end of the H-shaped paddle blade is lifted to the back side of the H-shaped paddle blade forward of the rotation direction of the H-shaped paddle blade.

In the stirring device according to the present invention, the H-shaped paddle blade adjacent to the wide paddle blade of the main blade is 1% or more, particularly 5% or more with respect to the height h of the wide paddle blade in the vertical direction with respect to the main blade. It is preferable that the fluids that wrap around to the back side of the blade at the lower end of the H-shaped paddle blade be combined with the wraparound flow that occurs at the upper end of the wide paddle blade (see FIG. 7).

Of course, in order to join the wraparound flow, the effect is reduced by the overlap that reaches the flow path, so that the range is preferably 50% or less, particularly 40% or less.

The overlap between the H-shaped paddle blade and the wide paddle blade is based on the uppermost end of the wide paddle blade. Since there is a recess in the upper center of the wide paddle blade,
The overlap between the H-shaped paddle blade and the wide paddle blade has a substantially triangular or trapezoidal shape (see FIG. 8). By making the degree of overlap thin near the axis and thicker away from the axis in this way, the wraparound flow created by the H-shaped blade and the wide paddle blade becomes obliquely downward, and the downflow can be efficiently guided to the mainstream ( See FIG. 8 (A).

The blade diameter (blade span) of the H-shaped paddle blade is small,
When the fluid wraps around at a portion relatively close to the stirring axis, the flow joins into a region where streamlines are rough (upstream region when compared to a river) (see FIG. 8 (A)).

In this case, the fluid lifted to the back side of the lower end of the H-shaped blade is dropped into the negative pressure section on the back side of the wide paddle blade. That is, when the blade diameter of the H-shaped paddle blade is small, it acts to strengthen the downflow near the stirring shaft. In addition, the wraparound flow at the lower end of the H-shaped paddle blade, which merges with the wraparound flow at the upper end of the main wing, moves toward the wall surface of the stirring tank on the back side of the main wing and joins the discharge flow (main flow) generated at the back side of the main wing. Discharge flow of the wide paddle blade, which is the main wing (mainstream)
Will also strengthen.

It is particularly preferable to form a concave portion at the center of the upper end of the wide paddle blade in order to efficiently join the wraparound flow.

Similarly, in the case where the diameter of the H-shaped paddle blade (blade span) is large and fluid wraps around at a position relatively distant from the agitation axis, the wraparound flow at the lower end of the H-shaped paddle blade is similarly changed to that at the upper end of the wide paddle blade. It can be combined with the wraparound flow (see FIG. 8 (B)).

In this case, since the wraparound flow generated at the lower end of the H-shaped paddle blade joins the dense portion of the streamline on the back side of the main wing (main stream), the wraparound flow at the lower end of the H-shaped paddle blade descends. Immediately after being converted to a flow, it is converted to a discharge flow. Therefore, when the diameter of the H-shaped blade is large, the discharge flow of the main blade is strengthened, but the effect of strengthening the downflow near the axis can hardly be expected. For example, Japanese Patent Laid-Open No. 4-90
In the gate-shaped blade described in Japanese Patent No. 839, since the gate-shaped blade and the blade installed at the bottom of the tank have almost the same diameter (same span), the effect of strengthening the downward flow (axial flow) cannot be obtained. On the other hand, in the present invention, since the H-shaped paddle blade is designed to have a smaller span than the wide paddle blade, the downward flow (axial flow) can be strengthened.

Further, the H-shaped paddle blade has a function of preventing the powder from adhering to the stirring shaft. When only wide paddle blades are used without installing H-shaped paddle blades, the powder put into the stirring tank while stirring a high-viscosity fluid is in close contact with the stirring shaft from the fluid surface along the stirring shaft. Is drawn into the liquid.

On the other hand, when the H-shaped paddle blade is installed,
Due to the negative pressure generated on the back surface of the vertical blade extending in the vertical direction of the blade tip, the powder drawn into the liquid draws a spiral while receiving the attractive force of this negative pressure portion, near the upper end of the wide paddle blade which is the main blade. Since it is pulled up to (see FIG. 6), there is an effect of preventing the powder from adhering to the stirring shaft.

[0049]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the scope of these examples.

Example 1 To confirm the effect of mixing and stirring powder in a medium viscosity solution, 1.2 liters of a starch syrup aqueous solution having a viscosity of 8 Pa · s and 1 g of granular sugar were prepared. It should be noted that it is preferable to confirm the state of mixing and stirring using these materials by a simple method.

Further, as an agitator having a structure as shown in FIG. 1, an inner diameter D = 130 having a 10% dish-shaped lower mirror.
A glass separable flask having a length of mm and a straight body length L of 1.4D was prepared. The H-shaped paddle blade has a blade diameter ds = 0.4
0D, blade height hs = 0.38D with respect to tank inner diameter.
The wide paddle blade has a blade diameter d = 0.77D and a blade height h = 0.30D with respect to the tank inner diameter. Note that the overlap of the H-shaped paddle blades is 27% of the height of the wide paddle blades in the stirring axis direction.
And Also, two round bar baffles having a width of 5% with respect to the inner diameter of the tank were used. The rotation speed of this stirring device is 100 min.
^-1 (stirring power is 1.7 kWm ^-3 ).

The H-shaped paddle blade is 45 ° more than the wide paddle blade.
It was placed at a crossing angle of 1 to precede the rotation direction, the dispersed state of the granulated sugar was visually confirmed, and the time until it was uniformly dispersed was measured and found to be 1.3 minutes.

(Comparative Example 1) A dispersed state of granular sugar was carried out in the same manner as in Example 1 except that the H-shaped paddle blade was arranged ahead of the wide paddle blade at an intersection angle of 90 ° in the rotational direction. Was visually confirmed and the time until uniform dispersion was measured was 14 minutes.

(Comparative Example 2) The dispersion state of the granular sugar was visually confirmed and uniformly dispersed in the same manner as in Example 1 except that the H-shaped paddle blade and the wide paddle blade had a crossing angle of -45 °. It was 22 minutes when the time until it was measured was measured.

From the results of Example 1 and Comparative Examples 1 and 2, it is understood that the dispersion time can be significantly shortened by allowing the H-shaped paddle blade to precede the wide paddle blade in the rotational direction. In any case, adhesion of granular sugar to the stirring shaft was not observed.

Example 2 In order to confirm the effect of mixing and stirring powder in a highly viscous solution, a viscosity of 15 Pa · s
1.8 liter of starch syrup aqueous solution and 1 g of granular sugar were prepared.
Further, as a stirring device having a structure as shown in FIG.
Inner diameter D = 130mm, length L with 10% dish-shaped lower mirror
= 1.4D glass separable flask was prepared.
The H-shaped paddle blade has a blade diameter ds = 0.40D and a blade height hs = 0.38D with respect to the tank inner diameter. The wide paddle blade has a blade diameter d = 0.60D and a blade height h = 0.45 with respect to the tank inner diameter.
It is D. The overlap of the H-shaped paddle blades was set to 15% of the height of the wide paddle blades in the stirring axis direction. Two flat plate baffles having a width of 10% with respect to the inner diameter of the tank were used. The rotation speed of this stirring device was set to 80 min ⁻¹ (the stirring power was 1.5 kWm ⁻³ ).

The H-shaped paddle blade is 45 ° more than the wide paddle blade.
It was placed at a crossing angle of 1 to precede the rotation direction, the dispersed state of the granular sugar was visually confirmed, and the time until it was uniformly dispersed was measured, and it was 6 minutes. No granule sugar was attached to the stirring shaft.

(Comparative Example 3) When a stirring device (stirring power is 1.5 kWm ^-3 ) corresponding to the device using the large two-stage paddle blade described in JP-A-5-49890 is used, the dispersion time is 9 minutes. Met. No granule sugar was attached to the stirring shaft.

(Comparative Example 4) Dispersion time was 12 minutes when a stirring device (stirring power was 1.5 kWm ^-3 ) corresponding to the device using a single gate blade described in JP-A-61-200842 was used. Met. No granule sugar was attached to the stirring shaft.

Comparative Example 5 When the pitched paddle blade (tilted paddle blade) with d = 0.60D was used in two stages (stirring power was 1.5 kWm ⁻³ ), the dispersion time was 13 minutes. Adhesion of granular sugar to the stirring shaft was observed.

(Comparative Example 6) When a flat disk turbine of d = 0.5D is used in two stages (the stirring power is 1.5 k
Wm ^-3 ) was not uniformly dispersed even after stirring for 120 minutes. Adhesion of granular sugar to the stirring shaft was observed.

From the above results, it can be seen that the stirring device of the present invention has a higher ability to disperse the powder in the high-viscosity liquid than the existing stirring device.

[0063]

As described above in detail, the stirrer according to the present invention prevents the powder / liquid from accumulating, particularly when mixing the powder in a medium or high viscosity fluid. It is possible to prevent the powder from adhering to the stirring shaft while improving the entrainment in the liquid and the solid-liquid mixing property.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a stirrer of the present invention.

FIG. 2 is a schematic diagram showing another embodiment of the stirring device of the present invention.

FIG. 3 is a schematic view showing another embodiment of the stirring device of the present invention.

FIG. 4 is a schematic view showing another embodiment of the stirring device of the present invention.

FIG. 5 is a combination example of an H-shaped paddle blade and a wide paddle blade used in the stirring device of the present invention.

FIG. 6 is a conceptual diagram showing powder flow when liquid and powder are mixed by the stirring device of the present invention.

FIG. 7 is a conceptual diagram showing a side view of a fluid flow between an H-shaped paddle blade and a wide paddle blade in the stirring apparatus of the present invention.

FIG. 8 is a conceptual view of a fluid flow between an H-shaped paddle blade and a wide paddle blade as viewed from the front in the stirring device of the present invention.

[Explanation of symbols]

1 stirring tank 2 stirring shaft 3 wide paddle wings 4 H type paddle wing 4'H type paddle wing 5 Rectification means

Claims (7)

[Claims] 1. A stirring shaft is provided at the center of a vertical cylindrical stirring tank, a wide paddle blade is arranged on the stirring shaft so as to be close to the bottom of the tank, and further on the stirring shaft above the wide paddle blade. To 1
The H-shaped paddle blades having a number of stages or more are arranged, and the H-shaped paddle blades are 0 to 90 more than the stirring blades in the lower stage vertically adjacent to the rotation direction.
An agitating device, characterized in that the agitating blades are preceded by a crossing angle of °, and a part of the agitating blades vertically adjacent to each other are overlapped. 2. The stirring device according to claim 1, wherein the crossing angle between the H-shaped paddle blade and the lower stirring blades vertically adjacent to each other is 30 to 60 °. 3. The H-shaped paddle blade and the lower-stage stirring blades vertically adjacent to each other with respect to the height of the wide paddle blade in the stirring axis direction,
The stirring device according to claim 1 or 2, which has an overlap of 1% to 50%. 4. The vertical length of the H-shaped paddle blade is in the range of 1/2 to 4 of the blade diameter of the H-shaped paddle blade.
The stirring device according to any one of 1 to 3. 5. The stirring device according to claim 1, wherein the blade diameter of the H-shaped paddle blade is in the range of 1/3 to 3/4 of the blade diameter of the wide paddle blade. 6. A shape in which the tip of the wide paddle blade installed at the lowermost stage is recessed with respect to the rotation direction.
The stirring device according to any one of 1. 7. The stirrer according to claim 1, wherein the wide paddle blade installed at the lowermost stage has a recess at the center of the upper end.