JP2000197816A - Vertical type stirring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical type stirring apparatus capable of shortening the up-and-down evenly stirring time, making the flow rate even in the upward and downward directions, and shortening the heat transmission time in a high liquid and deep stirring tank, a stirring tank comprising an acute angle conical bottom having a half apical angle of 60 deg. or narrower, or a stirring tank of a combination of these tanks. SOLUTION: A rotatable rotation axis 8 is installed in the center of a stirring tank from the outside of the tank, bottom paddle blades with a large surface area are attached to a lower part of the rotation shaft 8, and grid blades 3 produced by combining a vertical grid 1 and a transverse arm 2 are installed in the rotation shaft 8 in the upper side of the bottom paddle blades. The distance between the outer rim parts of the vertical grids 1 in the outermost side of the grid blades 3 and the center of the rotation shaft 8 is made wider than that of the bottom paddle blades. Furthermore, the width of the vertical grids 1 is made wider in the upper side and narrower in the lower side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirrer used for stirring various fluids, semi-fluids, powders and the like in a tank, particularly a high liquid deep stirring tank or an acute angle conical bottom type stirring tank. The present invention relates to a vertical stirring device capable of achieving uniform mixing.

[0002]

2. Description of the Related Art Generally, a stirring apparatus of this type is provided with a rotating shaft having stirring blades at the center of a stirring tank so as to protrude from the tank, and by rotating the rotating shaft from outside the tank. ,
With the rotation of the stirring blade, a swirling flow and a vertically circulating flow are generated in the processed material (substance to be stirred) in the tank to perform stirring and mixing.
As a conventional stirring blade, a discharge-type blade such as a turbine blade, a paddle, a propeller, a retreating blade, or a shear-type stirring blade such as a gate, a helical ribbon blade, a screw, or an anchor is known.

FIG. 5 is a sectional view of a conventional stirring device using two-stage turbine blades. In this example, the stirring tank 20 has a conical bottom shape with a bottom having a half apex angle α, and a rotating shaft 21 that is rotationally driven from outside is provided at the center of the tank so as to extend the entire length of the tank. One or more stirring blades 2
3 is attached. The stirring blade 23 discharges the liquid to the surroundings by the rotation of the rotation shaft 21 and circulates the liquid in the tank by the discharged flow. The coil 24 may be installed on the inner periphery of the tank 20.

[0004]

In a conventional stirring blade, for example, in the case of a high liquid depth stirring tank (L / D> 1.5 in the ratio of the liquid depth L from the tank bottom to the liquid surface and the tank inner diameter D). And uniform mixing up and down cannot be achieved. In an acute-angle conical bottom type stirring tank having a half apex angle of 60 ° or less, a stagnant portion of the liquid is generated at the tip of the conical, and the mixing does not proceed at that portion. In particular, when the coil is installed in the peripheral part in the tank, the above-mentioned problem becomes more remarkable.

With reference to FIG. 5 and FIGS. 6 to 9, the above-mentioned conventional disadvantage will be described in detail. When the discharge type stirring blade 23 is used in one stage as shown in FIG.
(The joint line between the tank body and the conical part)
Is installed, but when the state of high liquid depth is reached, the tank bottom 20a
Since the moving distance from the liquid to the liquid surface 25 is long, the flow velocity is attenuated (portion A in FIG. 6) during the movement of the discharged liquid, and the upper and lower uniform mixing is not achieved, and the portion B in FIG. Stagnation occurs.

As shown in FIG. 7, a stirring blade may be used in a multi-stage configuration of two or more stages in order to eliminate the non-uniform state. However, a collision of the discharge flow occurs between the blades 23a and 23b, and As shown at 26, it is as if a partition is provided, and the upper and lower uniform mixing is rather hindered by the partition-like liquid phase.

In the conical bottom type stirring tank 20 having a half apex angle of 60 ° or less in FIGS. 5, 8 and 9, since the cross-sectional area becomes smaller as approaching the conical tip, fluid resistance occurs when the liquid flows. It will be easier. For this reason, the liquid does not actually flow to the tip of the tank, but tends to flow to the side with less resistance, so-called flow separation occurs. As a result, a liquid stagnation portion 27 is generated at the tip of the conical. This tendency increases as the viscosity increases. Note that the hatched portions in FIG. 5 indicate portions where the liquid has a poor flow.

[0008] Further, it is generally said that shear-type agitating blades such as gates, helical ribbon blades, screws, and anchors rotate at a low speed to promote mixing by lifting or scraping a liquid. In this case, the performance of these shearing blades as nominal is limited to a so-called laminar flow region having a Re number of at least 100 or less, and otherwise forms a vertical circulating flow of liquid. The ability is very low. When the Re number is 100 or more, the upper and lower mixing hardly proceeds. The Re number is the number of Reynolds nozzles and is represented by d ² nρ / μ. Here, d is the diameter of the stirring blade [m], n is the rotation speed of the blade [1 / s], and ρ is the density [kg].
/ M ³ ] and μ are viscosities [kg / m · s].

Further, in the conventional agitating device, almost all combinations of blade shapes and blades form an upward flow (reference numerals 28 and 29 in FIG. 5) near the wall surface. No ascending flow can be formed at the center of the bottom. Furthermore, at high liquid depth or with a coil, the flow velocity attenuates on the way, so that the inside of the tank does not become a single circulation flow, but rather a number of sub-circulation flows (flows isolated from the entire flow) are formed. However, the uniform mixing property in the entire tank is extremely poor.

The present invention eliminates the above-mentioned conventional disadvantages,
Shortening of the mixing time in the vertical direction in a high liquid depth stirring tank, or a stirring tank using an acute conical bottom with a half apex angle of 60 ° or less, or a combination thereof, uniform flow velocity in the vertical direction and heat transfer An object of the present invention is to provide a vertical stirring device capable of achieving a reduction in time.

[0011]

According to the vertical stirring device of the present invention, a rotary shaft rotatable from outside the tank is disposed at the center of the stirring tank, and a bottom paddle blade is mounted below the rotary shaft. On the rotation axis above the bottom paddle wing, a lattice wing combining a vertical grid and a horizontal arm is installed, and the distance between the outer edge of the outermost vertical grid of the lattice wing and the center of the rotation axis is set as the distance. It is larger than that of the bottom paddle wing.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a vertical stirring device according to one embodiment of the present invention. In this figure, the outer tank case 10 is shown by imaginary lines for clarity. The stirring tank has a tank case 10 composed of a straight body 6, a substantially inverted conical tank bottom 7, and a lid 13 for closing the upper part of the straight body 6, and has a tank bottom in the center thereof. A stirring shaft (rotating shaft) 8 is provided extending through the lid 13. Lid 1
The stirring shaft 8 projecting upward from 3 is connected to an output shaft of a motor 9 mounted on an upper part of the lid and a reduction gear 18, and is driven to rotate by the bias of the motor 9. A heat transfer coil 11 is provided near an inner wall of the tank case 10 from the straight body 6 to the tank bottom 7 via a suitable coil support 12. In the illustrated example, the coil 11 is doubled,
It may be single or multiple. A baffle is provided on the inner wall of the tank case 10 as needed, but this baffle may be shared by the coil support 12 as in the illustrated embodiment. The case 10 is provided with a nozzle 14 for passing cooling water or a heat medium through the coil 11.

The stirring shaft 8 is rotatably supported by a bottom plate 15 of the tank bottom 7 and a lid 13 at the top of the tank. A conical bottom paddle blade 5 having a large lateral projection area is attached to a stirring shaft 8 provided at a position corresponding to the tank bottom 7. As shown in the figure, the paddle blade 5 has a tip (lower end) side 5a formed at an acute angle along the inverted cone of the tank bottom 7, and has a vertical outer portion 5b near the upper end. The paddle wing 5 is tilted, bent,
It may be in the form of being retracted. In addition, the above-mentioned inclination means that the paddle blade 5 is inclined when viewed from the horizontal / vertical direction, refraction means that the paddle blade 5 is bent when viewed from the vertical direction, and retreat means from the vertical direction. This means that the paddle wings 5 are curved.

The stirring shaft 8 above and adjacent to the paddle blade 5
Has a plurality of horizontal arms 2 attached to the stirring shaft 8 and a vertical grid 1 provided at the tip of the horizontal arm 2 and extending in parallel with the stirring shaft 8. 1 and 2 (A), (B), FIG. 3 (A),
Referring to (B), the distance L between the outermost edge 1a of the vertical grid 1 at the outer end of the horizontal arm 2 and the center of the stirring shaft 8 is the maximum width W on one side of the large paddle blade 5 on the lower side (FIG. 1). It is bigger. The vertical grid 1 has a wide upper portion and a narrow lower portion as a whole. In this case, as shown in FIG. 1, the inside of the lower portion is cut out in one step, or the inside is cut out in multiple steps as shown in FIG. As shown in FIG. 3B, the inside may be cut away continuously from the upper part to the lower part so that the width of the lower part is reduced.

One or more intermediate vertical grids 4 are further provided on the horizontal arm 2 between the stirring shaft 8 and the vertical grid 1 at the outer end of the horizontal arm. The vertical grid 1 at the outer end of the arm may be attached in such a manner as to be inclined with respect to the flow of the liquid as shown in FIG. 2A or to be retracted as shown in FIG. The arrows shown in FIGS. 3A and 3B both indicate the rotation direction of the stirring shaft 8.

FIG. 4 is a side view schematically showing the flow of liquid during operation of the stirring tank when the tank is viewed from the side in the embodiment shown in FIG. As described above, since the width of the vertical grid 1 is made wider at the upper portion and narrower at the lower portion, a downward flow 16 is generated near the inner wall surface of the tank body 6. Since the side of the lower large paddle blade 5 extends along the wall surface of the conical tank bottom 7 from near the upper portion to the lower side, a flow 17 toward the tank bottom wall is generated here. It acts to send out the liquid upward from the tank bottom (reference numeral 19). By combining this downward flow 16 on the wall side of the straight body portion and the action of the lower large paddle blade 5 to suck up the liquid at the bottom of the tank without interfering with each other, a so-called single-stroke circulation flow (continuous sub-circulation flow is generated). ), Thereby shortening the uniform mixing time and making the flow velocity uniform over the entire area in the tank.

In the present invention, since the bottom paddle blade 5 having a large area is installed below the lattice blade 3, the shape of the bottom of the stirring tank is changed to a half apex angle by the action of sucking the liquid at the bottom of the tank by the large blade. Even with an acute angle of 60 ° or less, uniform mixing can be realized without causing liquid to stay at the tip of the tank bottom.

Further, the tank bottom is conical with a half apex angle of 60 ° or less, and has a high liquid depth (the ratio of the liquid depth L from the tank bottom to the liquid surface to the tank inner diameter D, L / D> 1.5). Even in the case of a shape, the range of the operable liquid amount range is wide, and the maximum liquid amount is 200.
It is possible to cope with a liquid amount of 1 /. That is, in the case where the liquid amount of the operation is large when the liquid amount of the operation is increased to 200 at the end when the initial amount is set to 1, the present invention uses a combination of two types of tanks, large and small. And one tank.

In the case of a stirring tank equipped with a coil, if the outer diameter of the vertical grid 1 of the upper lattice blade is set to 0.7 or more with respect to the winding diameter dc of the inner coil 11 in the present invention, it is installed close to the coil. In addition, the flow velocity near the heat transfer jacket and the coil due to the discharge flow from the blade is significantly higher than that of the conventional stirring blade, and as a result, high heat transfer performance can be realized.

In the above-described embodiment, the bottom of the stirring tank is an acute-angle conical bottom type, but the present invention is not limited to such a structure.
For example, a stirring tank as shown in FIGS. 6 and 7 may be used. In this case, a so-called one-stroke liquid flow is obtained for the entire tank.
It is possible to reduce the time required for the mixing in the vertical direction in the stirring tank, the flow velocity in the vertical direction, and the heat transfer time.

[0021]

As described above, according to the present invention, the width of the vertical grid of the lattice wing is made wider at the upper part and narrower at the lower part, and the outermost edge of the vertical grid is made smaller than the large paddle wing at the lower part. Since the outer diameter is larger than the outer diameter, a downward liquid flow is generated along the tank wall surface.On the other hand, even when the tank bottom is of a conical bottom type, the large paddle blade sucks up the liquid at the tank bottom, so that the tank has A single-stroke circulating flow can be formed with the vicinity of the wall facing downward. Shortening of the vertical mixing time in a high liquid depth stirring tank or a stirring tank using an acute conical bottom with a half apex angle of 60 ° or less, vertical direction This has the effect of making the flow velocity uniform and reducing the heat transfer time.

[Brief description of the drawings]

FIG. 1 is a side view of a vertical stirring device according to one embodiment of the present invention.

FIG. 2 is a plan view showing a case where a vertical grid according to an embodiment of the present invention is attached to a horizontal arm so as to be inclined or retracted.

FIG. 3 is a front view showing an embodiment in which the width of a vertical grid is changed according to the embodiment of the present invention.

FIG. 4 is a side view schematically showing the flow of the liquid during the operation of the stirring tank in the embodiment shown in FIG.

FIG. 5 is a cross-sectional view of a stirring device using a conventional two-stage turbine blade.

FIG. 6 is a schematic view of a conventional stirring device using a discharge type single-stage blade.

FIG. 7 is a diagram showing a state where upper and lower liquids are separated by a conventional stirring device using two-stage blades.

FIG. 8 is a view showing a state in which a liquid retention section is formed at the bottom of a conventional conical bottom type stirring tank.

FIG. 9 is a view showing a state in which a liquid retaining portion is formed at the bottom of a conventional conical bottom type stirring tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical grid 2 Horizontal arm 3 Grid wing 5 Conical bottom paddle wing 6 Straight body 7 Tank bottom 8 Stirring shaft 9 Motor 10 Tank case 11 Coil 12 Coil support

Continuing from the front page (72) Inventor Masafumi Kuratsu 1501 Imaiza, Toyo City, Ehime Prefecture Sumitomo Heavy Industries Industrial Co., Ltd. Inventor Mineo Nakano 1F term of 11F, Hitotsubashi Nohonmachi, Higashiyama-ku, Kyoto-shi, Kyoto 4G078 AA04 BA05 CA01 DA01 DB01 DC10

Claims (5)

[Claims] 1. A rotary shaft rotatable from outside the tank is disposed at the center of the stirring tank, a bottom paddle blade is mounted below the rotary shaft, and a vertical grid is mounted on the rotary shaft above the bottom paddle blade. And a lattice wing in which a horizontal arm is combined, wherein the distance between the outer edge of the outermost vertical grid of the lattice wing and the center of the rotation axis is larger than that of the bottom paddle wing. Vertical stirrer. 2. The vertical stirrer according to claim 1, wherein the width of the outermost vertical grid of the lattice blade is wide on the upper side and narrow on the lower side. 3. The outermost vertical grid of the lattice wings,
The vertical stirrer according to claim 1, wherein the stirrer is inclined in a circumferential direction of the stirring tank with respect to the horizontal arm. 4. The outermost vertical grid of the grid wings,
2. The horizontal arm is curved and inclined in a circumferential direction of the stirring tank along a flow of the stirring liquid.
Item 4. The vertical stirring device according to Item 3. 5. The conical bottom having an acute angle conical shape with a half apex angle of not more than 60 ° at a bottom portion of the stirring vessel, and having an outer shape along a half apex angle of a conical bottom shape bottom of the stirring vessel below the rotating shaft. The vertical stirrer according to any one of claims 1 to 4, further comprising a paddle blade.