WO2006033276A2

WO2006033276A2 - Stirring apparatus

Info

Publication number: WO2006033276A2
Application number: PCT/JP2005/017031
Authority: WO
Inventors: Shoji Morinaga; Ryuichi Yatomi
Original assignee: Shi Mechanical & Equipment Inc.
Priority date: 2004-09-22
Filing date: 2005-09-15
Publication date: 2006-03-30
Also published as: JP2006087998A

Description

Specification

mixer

Technical field

[0001] The present invention relates to a stirrer for stirring treatment for the purpose of mixing, dissolution, crystallization, reaction and the like.

Background art

Conventionally, there are many examples in which small blades such as turbine blades, paddle blades, and propeller blades are used in multiple stages as the stirring blades of a stirrer. In a stirrer using these stirring blades, by increasing the blade rotation speed and increasing the flow rate of the liquid discharged from the blade in the radial direction, the liquid collides with the tank wall and rotates upward and downward, and again. A circulating flow returning to the wing is generated, and mixing in the tank is performed. Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the small wing, a plurality of partition zones Z,... Are formed between the upper and lower sides where it is difficult to form a sufficient up-and-down circulation flow throughout the tank as shown in FIG. End up. Therefore, the stirring characteristics deteriorated, the gas absorption reaction took time, and the solid dispersion became non-uniform, resulting in non-uniform product quality and increased reaction time.

[0004] Accordingly, an object of the present invention is to provide a stirrer that can form a sufficient up-and-down circulation flow throughout the tank and can exhibit suitable stirring characteristics. Means for solving the problem

[0005] The stirrer according to the present invention is a stirrer in which a stirring shaft 2 that is rotatable by an external force of the tank is disposed in the central portion of the stirring tank 1, and the stirring blade 3 is attached to the stirring shaft 2. When the stirring blade 3 performs stirring in the range of (i) Reynolds number Re of 300≤Re, the ratio of the outermost radius of the stirring blade 3 to the diameter of the stirring tank 1 (blade diameter ratio) is 0.225- 0.325, and stirring in the lower half D with respect to the integral value in the axial direction of the product of the effective area of the stirring blade 3 in the upper half U and the cube of the outermost radius of the stirring blade 3 in the effective area The ratio of the integral value (discharge flow rate ratio) in the axial direction of the product of the effective area of blade 3 and the cube of the outermost radius of stirring blade 3 in the effective area is 1.4 or more, and (ii) Reynolds number When stirring is performed in a range where Re is 30≤Re and 300, the blade diameter ratio is 0.25 to 0.325, and the discharge flow rate ratio is 1.7 or more. Yes, when stirring is performed in a range where the Reynolds number Re is Re 30, the blade diameter ratio is 0.325 to 0.375, and the discharge flow rate ratio is 1.8 or more. It is characterized by this.

[0006] According to the stirrer having the above-described structural force, the lower half D force of the stirring blade 3 The discharge flow rate of the stirring object discharged in the radial direction is the stirring flow discharged in the radial direction from the upper half U of the stirring blade 3. More than the discharge flow rate of the object. Therefore, a vertical circulation flow from a strong discharge region to a weak discharge region, that is, a continuous vertical circulation flow from the lower part to the upper part of the stirring tank 1 is formed. As a result, the agitated object is formed as a whole without the partition zone.

The invention's effect

[0007] That is, the stirrer according to the present invention forms sufficient vertical circulation flow throughout the tank by optimizing the blade diameter ratio and the discharge flow rate ratio in accordance with the agitation operating conditions. Therefore, suitable stirring characteristics can be exhibited.

Brief Description of Drawings

FIG. 1 shows a front view of a stirrer according to the present embodiment.

FIG. 2 is a conceptual diagram for explaining stirring characteristics of the stirrer according to the embodiment.

[Fig. 3] A data table of stirring characteristics (mixing characteristics) in relation to the discharge flow rate ratio and blade diameter ratio when stirring is performed in the range of 300≤Re.

[Fig. 4] A graph showing the quality of the stirring characteristics (mixing characteristics) in relation to the discharge flow rate ratio and blade diameter ratio when stirring is performed in the range of 300≤Re.

[Fig. 5] A data table of the agitation characteristics (mixing characteristics) in the relationship between the discharge flow rate ratio and the blade diameter ratio when agitation is performed in the range of 30≤ReRe300.

[Fig. 6] A graph showing the quality of the stirring characteristics (mixing characteristics) in the relationship between the discharge flow rate ratio and the blade diameter ratio when stirring is performed in the range of 30 ≤ Re 300.

[Fig. 7] A data table of stirring characteristics (mixing characteristics) in relation to the discharge flow rate ratio and blade diameter ratio when stirring is performed in the range of Re 30.

[Fig. 8] A graph showing the quality of the stirring characteristics (mixing characteristics) in the relationship between the discharge flow rate ratio and the blade diameter ratio when stirring is performed in the range of Re 30. FIG. 9 shows a front view of a stirrer according to another embodiment.

FIG. 10 is a conceptual diagram for explaining stirring characteristics of a stirrer according to a conventional small blade. Explanation of symbols

[0009] 1 ... stirring tank, 2 ... stirring shaft, 3 ... stirring blade, 4 ... turbine blade, 5 ... bottom blade, 6 ... baffle plate, R, R

1 2… Vertical circulation flow, Q, Q, Q, Q

1 2 3 4… Discharge flow rate

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an agitator according to an embodiment of the present invention will be described with reference to FIG.

[0011] Reference numeral 1 denotes a cylindrical stirring tank, and a stirring shaft 2 is disposed in the center of the tank 1. The stirring shaft 2 is supported via a bearing (not shown) having a lower end provided at the bottom of the tank, and an upper end via a coupling (not shown) to a driving device (not shown) on the top of the tank. Connected.

[0012] 3 is a stirring blade, and 4 of the stirring blades 3 are multi-stage (three-stage in this embodiment) turbine bin blades of the disk 4a concentrically attached to the stirring shaft 2. A plurality of blades 4b,... Are attached to the outer circumference equally divided positions. Each turbine blade 4 is formed such that the shape of the blade 4b becomes smaller toward the top.

[0013] Reference numeral 5 denotes a bottom blade, which is attached to the lower end of the stirring shaft 2. The bottom blade 5 is a flat blade having a substantially rectangular shape, and the lower end edge is formed in a curved shape so as to follow the curved shape of the tank bottom.

[0014] Reference numeral 6 denotes a baffle plate, which is a side wall surface of the agitation tank 1, and a plurality of them are attached at a predetermined interval in the circumferential direction (only one is shown in the figure). This baffle plate 6 is continuous along the axial length direction from the lower side to the upper side of the side wall of the stirring tank 1, and stirs the stirring object discharged from the stirring blade 3 consisting of the turbine blade 4 and the bottom blade 5 It has the characteristic of rising to the top of tank 1.

[0015] The stirrer according to the present embodiment has the above-described configuration. Next, the stirring characteristics of the stirrer according to the present embodiment will be described with reference to FIG.

[0016] The discharge flow rate of the stirring object discharged in the radial direction from the blade is the product of the effective area in the axial length direction of the stirring blade 3 and the cube of the outermost radius of the stirring blade 3 in the effective area. It is generally known that it is proportional to. Therefore, a stirring blade 3 such as the stirring blade 3 according to the present embodiment. If the total effective area of the stirring blade 3 in the lower half D is large, the discharge flow rate (Q + Q) of the stirring object in the lower half D is

1 2 Upper half More than the discharge flow rate (Q + Q) of the stirring object in U. “Upper half”

3 4

Is the upper side when the bottom end force of the stirring blade 3 is also divided by half the height to the top end, and the “lower half” means the lower side.

[0017] Then, due to the difference in the discharge flow rate between the upper half U and the lower half D of the stirring blade 3, that is, the difference in discharge strength, the vertical circulation flow R from the strong discharge region to the weak discharge region R, , Stirring tank

1

A continuous vertical circulation flow R from the lower part of 1 to the upper part is formed. as a result,

1

Since the stirring object can be stirred as a whole without the partition zone being formed, the stirring characteristics are improved. In particular, in the present embodiment, the effective area of the stirring blades 3 in each stage gradually decreases from the lower force to the upper force, so the discharge flow rate Q of the bottom blade 5>

1 Discharge flow rate of one-bin blade 4 Q> Middle turbine blade 4 Discharge flow rate Q> Upper turbine blade 4

twenty three

Discharge flow rate Q

As a result, a more favorable vertical circulation flow is obtained.

[0018] In addition, the vertical circulation flow R moves from the side wall side to the center side of the stirring tank 1 after reaching the upper part.

1

However, it becomes a vertical circulation flow R that moves downward along the stirring shaft 2 and returns to the bottom of the tank.

2

Since the stirring blades 3 are provided in multiple stages (that is, when a gap is formed between the stirring blades 3 and 3), the stirring object being lowered is sheared and subdivided by these, and the finer blades are further reduced. It is agitated.

In FIG. 2, for easy understanding, the discharge flow rate (discharge flow) Q 1, Q 2, Q 3, Q 4

1 2 3 and vertical circulation flow R 1, R 2 are shown only on one side, but the circumferential direction of the stirring tank 1

4 1 2

Needless to say, the same flow pattern occurs in all areas! /.

[0020] Here, the present inventor conducted various experiments, regardless of how the stirring blade 3 is designed.

[0021] Fig. 4 shows the result of the following experiment, the experimental result (Fig. 3) is plotted, and the boundary line is drawn.

'Inner diameter D (Inner diameter of barrel of stirring tank 1): 310mm

• Blade height B (height from the lowest position at the bottom of the tank to the top end of the stirring blade 3): Liquid depth L (the highest at the bottom of the tank) Adjusted according to the height from the bottom position to the liquid level) and set 62mm lower than the liquid depth L

-Tank bottom shape: semi-elliptical

'Baffle plate: Yes

• Liquid volume: 23.8 ~ 37.8 g

'Agitation power: 0.5-2. OkW / m ³

• Tracer: 1mm square PS (polystyrene) pellets (specific gravity 1.05)

The stirring condition is set to a Reynolds number Re (liquid viscosity) in the range of 300≤Re, and using the colored tracer fluid method, it is judged whether the vertical circulation flow is not interrupted visually rather than by quantitative judgment of mixing time. It was. Incidentally, “◯” is an evaluation for the case where the flow discharged from the lower part of the stirring tank 1 smoothly reaches the upper part and one vertical circulation flow is formed in the vertical direction. The lower force of the stirring tank 1 is the force when the discharged flow almost reaches the upper part. It is an evaluation for the case where the flow to the center side is seen partway. It is an evaluation for the case where is divided.

[0022] Fig. 6 shows the experiment with the stirring conditions changed within the range of Reynolds number Re to 30≤Re and 300, and the experimental results (Fig. 5) are plotted and the boundary line is drawn.

[0023] Fig. 8 shows an experiment in which the agitation conditions are changed to a Reynolds number Re in the range of Re <30, the experimental results (Fig. 7) are plotted, and the boundary line is drawn.

[0024] Here, A is the effective area of each stirring blade 3, r is the outermost radius of each stirring blade 3, and D indicates the diameter (inner diameter) of the stirring tank 1. AX r ³ (bottom) is the sum of (AX r ³ ) of the stirring blades 3 in the lower half D of the stirring blade 3 (the effective area of the stirring blade 3 in the lower half D and the stirring area in the effective area). AX r ³ (upper) means each stirring blade in the upper half U of stirring blade ³ (the value obtained by integrating the product of the outermost radius of blade 3 and the cube of the outer radius in the axial direction of stirring shaft 2) The sum of (AX r ³ ) of ³ (the value obtained by integrating the product of the effective area of the stirring blade 3 in the upper half U and the cube of the outermost radius of the stirring blade 3 in the effective area in the axial direction of the stirring shaft 2 Means the same).

[0025] From Fig. 3 and Fig. 4, rZ D is 0.225-0.325 for turbulent flow (300 Reynolds number Re) and AX r ³ (below) ZA X r ^{If 3} (top) is 1.4 or higher, the flow state (mixing characteristics) is improved. RZD is called “blade diameter ratio” and AX r ³ (below) ZA X r ³ (top) is called the “discharge flow rate ratio”.

[0026] Further, from Figs. 5 and 6, the blade diameter ratio is 0.25-0.325 and the discharge flow rate ratio is about 0.25 to 0.325 for the stirring target in the transition basin (30 ≤ Reynolds number Re 300). 1. If it is 7 or more, it can be said that the flow state (mixing characteristics) is improved.

Furthermore, from FIG. 7 and FIG. 8, for the stirring object in the laminar flow area (Reynolds number Re 30)

If the blade diameter ratio is 0.325 to 0.375 and the discharge flow rate ratio is 1.8 or more, the flow state

The fact that (mixing characteristics) is improved is remarkable.

[0028] It should be noted that the stirrer according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

[0029] For example, in the above embodiment, the stirring blade 3 has the combined force of the turbine blade 4 and the bottom blade 5, but the blades as shown in FIG. In addition, the blades may be slanted as shown in Fig. 9 (b), or a paddle blade or propeller blade arranged in multiple stages, or A stirring blade that provides anchor blade force may be used. In the case of a stirring blade as shown in FIG. 9B, an average value is used for the outermost radius r of the stirring blade 3 for obtaining the blade diameter ratio.

[0030] In the above embodiment, the lower end of the agitation shaft 2 is supported by the tank bottom, but the lower end may not be supported by being separated from the tank bottom force. ,.

[0031] In the above-described embodiment, the driving device for rotating the stirring shaft 2 to rotate the tank external force is provided on the tank top side, but the driving device may be provided on the tank bottom side.

In the above embodiment, the baffle plate 6 is provided. However, the baffle plate 6 is not an essential component in the present invention.

[0033] The tank inner diameter D, the blade height B, and the liquid depth L are not particularly limited, but generally, the blade height ratio BZD (blade height BZ tank inner diameter D) is set to 50 to 100%. The liquid depth ratio LZD (liquid depth LZ tank inner diameter D) may be set to 10 to 150%.

[0034] In addition, for an object to be stirred in a turbulent flow region (300 ≤ Reynolds number Re), a transition flow region (30 ≤ Reynolds number Re 300) for the stirring target, the upper limit of the discharge flow rate ratio can be set to 1.9.For the stirring target in the laminar flow region (Reynolds number Re <30), the discharge flow ratio Even if 2.3 is set as the upper limit / vD / O IS / JOsooifcId 9 / -ίεεο900ίAV L

Claims

The scope of the claims

[1] A stirrer in which a stirring shaft (2) capable of rotating a tank external force is disposed in the central portion of the stirring tank (1), and a stirring blade (3) is attached to the stirring shaft (2). The stirring blade (3) is provided with the following conditions.

(i) When the Reynolds number Re is in the range of 300≤Re, the ratio of the outermost radius of the stirring blade (3) to the diameter of the stirring tank (1) (blade diameter ratio) is 0.225-0. 325 and the lower half of the integral value in the axial direction of the product of the effective area of the stirring blade (3) in the upper half (U) and the cube of the outermost radius of the stirring blade (3) in the effective area The ratio of the integral value (discharge flow ratio) in the axial direction of the product of the effective area of the stirring blade (3) in (D) and the cube of the outermost radius of the stirring blade (3) in the effective area is 1 4 or more

(ii) When stirring is performed in a range where the Reynolds number Re is 30≤Re <300, the blade diameter ratio is 0.25 to 0.325, and the discharge flow rate ratio is 1.7 or more.

(iii) When stirring is performed in a range where the Reynolds number Re is Re 30, the blade diameter ratio is 0.325-0.375 and the discharge flow rate ratio is 1.8 or more.