JPH11276875A - Structure of agitating blade of vertical agitating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid retention of a liq. on the tank bottom part of an agitating tank using a sharp angle conical bottom with a semi-vertical angle of at most 60 deg., to shorten time for up and down uniform mixing, to make flow rate in the up and down direction uniform and to shorten heat transfer time. SOLUTION: In a structure of a rotating blade of a vertical agitating apparatus which has an agitating tank 32 the bottom part of which is formed into a sharp angle conical shape with a semi-vertical angle of at most 60 deg., a rotating shaft 8 which is arranged at the center of this agitating tank and is rotated from the outside of the tank and an agitating blade fitted on this rotating shaft 8, this agitating blade is arranged on the bottom part position of the agitating tank 32 and has a conical bottom paddle part 31 provided with an outer shape along the semi-vertical angle of the conical bottom-shaped bottom part 7 of the agitating tank 32.

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 kinds of fluids, semi-fluids, powders, etc. in a tank, and more particularly to a stirring apparatus for a vertical stirrer applied to an acute conical bottom type stirring tank. Related to wing structure.

[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. 7 is a cross-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, as shown in FIG.
Since only one horizontal arm-shaped blade 30 similar to the stirring blade 23 in the tank body is provided at the bottom of the tank 1, a liquid retaining portion 27 is inevitably generated at the tip of the conical. The mixing does not progress in that part. In particular, when the coil is installed in the peripheral part in the tank, the above-mentioned problem becomes more remarkable.

Referring to FIG. 7 and FIGS. 8 to 11, the above-mentioned conventional problems 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 (A in FIG. 8) during the movement of the discharged liquid, and the upper and lower uniform mixing is not achieved. Stagnation occurs.

As shown in FIG. 9, a stirring blade may be used in a multi-stage configuration having 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 indicated by reference numeral 26, a state is obtained as if a partition wall was provided in the middle of the upper and lower portions of the tank, and uniform mixing in the upper and lower portions is rather hindered by the partition-like liquid phase.

The half apex angle of 60 ° in FIGS.
In the following conical bottom type stirring tank 20, the cross-sectional area becomes smaller as approaching the tip of the conical, so that fluid resistance when the liquid flows easily occurs. 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 stagnation portion 27 of the liquid is generated at the tip of the conical.
This tendency increases as the viscosity increases. Even with the paddle-shaped stirring blade 30 at the bottom of the tank, the stagnation in this part cannot be eliminated. The hatched portions in FIG. 7 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 [k
g / m ³ ] and μ are viscosity [kg / m · s].

Further, in the conventional agitating device, most of the blade shapes and combinations of the blades form an upward flow (reference numerals 28 and 29 in FIG. 7) 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 a number of sub-circulation flows (flows isolated from the entire flow) 28, 29 are formed. As a result, the uniform mixing property in the entire tank is extremely poor.

The present invention eliminates the above-mentioned conventional disadvantages,
No liquid stagnation occurs at the bottom of the tank in an agitation tank using an acute angle conical bottom with a half apex angle of 60 ° or less. An object of the present invention is to provide a stirring blade structure of a vertical stirring device that can be used.

[0011]

A stirring blade structure according to the present invention comprises: a stirring tank having a bottom formed in an acute conical shape having a half apex angle of 60 ° or less; a stirring tank disposed at the center of the stirring tank and rotationally driven from outside the tank; A rotating shaft and a stirring blade attached to the rotating shaft, wherein the stirring blade is disposed at a bottom position of the stirring tank and a half-top of a conical bottom-shaped bottom of the stirring tank. It has a conical bottom paddle with an outer shape along the corner.

[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 vertical sectional view of a vertical stirring device using a stirring blade structure according to one embodiment of the present invention. The stirring blade of this embodiment includes a conical bottom paddle portion 31 mounted below the stirring shaft (rotating shaft) 8. The area of the conical bottom paddle portion 31 is much larger than that of the conventional arm-shaped stirring blade 30 at the bottom of the stirring tank shown in FIG. It forms a side portion 31a that is close to and substantially along the semi-acute angle shape of the bottom portion 7. The upper edge 31b of the paddle portion 31 is provided with the conical bottom-shaped bottom portion 7 of the stirring tank 32 when the stirring shaft 8 is assembled to the stirring tank 32.
And in the vicinity of the boundary position of the straight body 6.

In this embodiment, the number of blades of the paddle portion 31 is four at 90 ° intervals around the stirring shaft 8 as shown in FIG. 2, but the present invention is not limited to this number of blades. Instead, two blades aligned in the diameter direction or three blades provided at equal intervals around the periphery may be used. Above the conical bottom paddle portion 31 in this embodiment, only the stirring shaft 8 is provided and no other blade is provided, but an appropriate blade may be attached to this portion. Further, the paddle portion 31 may have a structure in which the paddle portion 31 is inclined, bent or retracted. The inclination means the paddle part 3 when viewed from the horizontal and vertical directions.
1 means that the paddle portion 31 is bent when viewed from the vertical direction, and retreat means that the paddle portion 31 is curved.

In the embodiment shown in FIG. 1, by rotating the stirring shaft 8 by a driving source (not shown) outside the tank, the processing liquid is supplied from the side 31a of the conical bottom paddle 31 to the paddle 31.
As a result, it is extruded perpendicularly to the inner wall surface 7a of the tank bottom 7, flows downward along the inclined surface of the tank inner wall 7a, and rises along the shaft 8 near the stirring shaft 8 from the tip 7b of the tank bottom. Then, it descends again along the inner wall of the tank from the upper part in the tank 32,
As a result, the treatment liquid is repeatedly circulated in the tank, and is uniformly stirred, so that the processing liquid does not stay at the bottom of the tank as in the related art.

FIG. 3 is a side view of a vertical stirring device according to another embodiment of the present invention. In this figure, the outer shell tank case 10 is shown.
Are shown in phantom lines for clarity. The stirring tank 32 has a tank case 10 composed of a straight body 6, an inverted conical tank bottom 7, and a lid 13 for closing the upper part of the straight body 6, and the tank bottom is provided at the center thereof. A stirring shaft (rotating shaft) 8 is provided extending through the lid 13. The stirring shaft 8 projecting upward from the lid 13 is connected to an output shaft of a motor 9 and a speed reducer 18 mounted on the upper portion of the lid, and is rotated by the urging 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 coils 11 are double, but 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. In addition,
The case 10 is provided with a nozzle 14 for passing cooling water or 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 31 having a large lateral projection area is attached to the stirring shaft 8 at a position corresponding to the tank bottom 7. The stirring blade structure of this embodiment is composed of a conical bottom paddle portion 31 of the tank bottom 7 and a lattice blade portion 3 of the tank body 6. As shown, the conical bottom paddle portion 31 has a lower side portion 31a formed at an acute angle along the inverted cone of the tank bottom 7,
It has a vertical outer portion 31c near the upper end. The paddle portion 31 may have a form inclined, bent, and retracted as described with reference to FIG. In the case where the number of blades of both the lattice wing portion 3 and the conical bottom paddle portion 31 is two in the diameter direction, the positions of the vertical grid 1 of the lattice wing portion 3 and the blades of the paddle portion 31 are set in the circumferential direction. May be shifted from each other by 90 °.

The lattice blade section 3 attached to the stirring shaft 8 above and adjacent to the conical bottom paddle section 31 is provided at a plurality of horizontal arms 2 attached to the stirring shaft 8 and at the tip of the horizontal arm 2. And a vertical grid 1 extending parallel to the stirring axis 8. 3 and 4 (A),
5B, 5A and 5B, 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 equal to the lower large paddle portion 31. Is larger than the maximum width dimension W on one side (FIG. 3). The vertical grid 1 has a wide upper portion and a narrow lower portion as a whole. In this case, as shown in FIG. 3, the inside of the lower part is cut out in one step, or as shown in FIG. 5 (A), the inside is cut out in multiple steps and the form is changed stepwise in the vertical direction.
Alternatively, as shown in FIG. 5B, 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. 4A 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. 6 is a side view schematically showing the flow of liquid during operation of the stirring tank when the tank is viewed from the lateral direction in the embodiment shown in FIG. As described above, since the width of the vertical grid 1 is made wider at the upper part and narrower at the lower part, a downward flow 16 is generated near the inner wall surface of the tank body 6. Since the side of the lower large paddle portion 31 extends along the wall surface of the conical tank bottom 7 from near the upper portion to the lower portion, a flow 17 toward the tank bottom wall is generated here, and the center of the paddle portion 31 is formed. In this case, the liquid is sent upward from the tank bottom (reference numeral 19). By combining the downward flow 16 on the wall surface side of the straight body portion and the action of the lower large paddle portion 31 to suck up the liquid in the tank bottom 7 without interfering with each other, a so-called one-stroke circulation flow (continuous sub-circulation flow) Flow) can be formed, thereby shortening the uniform mixing time and uniforming the flow rate over the entire area in the tank.

Further, in the present invention, since the bottom paddle portion 31 having a large projected area is provided below the lattice wing portion 3, the large wing sucks up the liquid at the bottom of the tank.
Even when the shape of the bottom of the stirring tank has an acute angle of not more than 60 [deg.] Half apex, uniform mixing can be realized without causing the liquid to stay at the tip of the bottom of the tank.

Further, the tank bottom is a conical shape having a half apex angle of 60 ° or less and a high liquid depth (ratio L / D> 1.5 of the liquid depth L from the tank bottom to the liquid surface and the tank inner diameter D). 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, in the present invention, the outer diameter of the vertical grid 1 of the upper lattice wing is set to be 0.7 or more with respect to the winding diameter dc of the inner coil 11, and the tank is installed close to the coil. For example, the flow velocity in the vicinity of 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.

[0023]

As described above, according to the present invention, a conical bottom paddle having a large area along the conical bottom shape at the bottom of the stirring tank is provided at the bottom of the stirring tank below the stirring shaft. It is possible to perform a good stirring process without generating a stagnation portion of the processing liquid at the bottom. Further, in the case where another lattice wing is formed on the conical bottom paddle part, the width of the vertical grid of the lattice wing is made wider at the upper part and narrower at the lower part, and more vertically than the large paddle part at the lower part. Since the outermost edge of the grid is larger than the outer diameter of the paddle portion, a downward liquid flow is generated along the tank wall surface at the straight body portion of the tank, while the tank bottom portion of the conical bottom is formed by the large paddle portion. By drawing up the liquid, a single-stroke circulating flow with the wall surface of the tank facing downward can be formed, and uniform mixing up and down in a stirring tank using a sharp conical bottom with a half apex angle of 60 ° or less. This has the effect of reducing the time, equalizing the flow velocity in the vertical direction, and shortening the heat transfer time.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view of a vertical stirring device when a stirring blade structure having a conical bottom paddle portion according to one embodiment of the present invention is applied to a conical bottom type stirring tank.

FIG. 2 is a plan sectional view taken along line AA of FIG. 1;

FIG. 3 is a side view of a vertical stirring device according to another embodiment of the present invention.

FIG. 4 is a plan view when the vertical grid according to the embodiment of the present invention is attached to the horizontal arm so as to be inclined or retracted.

FIG. 5 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. 6 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. 7 is a cross-sectional view of a stirring device using a conventional two-stage turbine blade.

FIG. 8 is a schematic view of a conventional stirring device using a discharge-type single-stage blade.

FIG. 9 is a diagram showing a state where upper and lower liquids are separated by a conventional stirring device using two-stage blades.

FIG. 10 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.

FIG. 11 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 Lattice wing part 6 Straight body part 7 Tank bottom 8 Stirring shaft 9 Motor 10 Tank case 11 Coil 12 Coil support 31 Conical bottom paddle part 32 Stirring tank

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masao Yamaoka 1-1-1, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto, Kyoto Prefecture (72) Inventor Mineo Nakano 1, 1-1, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto, Kyoto

Claims (2)

[Claims] 1. A stirring tank having a bottom formed in an acute angle conical shape having a half apex angle of 60 ° or less, a rotating shaft disposed at the center of the stirring tank and driven to rotate from outside the tank, and attached to the rotating shaft. In the vertical stirring device having a stirring blade, the stirring blade is disposed at a bottom position of the stirring tank and has a conical bottom paddle portion having an outer shape along a half apex angle of a conical bottom shape bottom of the stirring tank. A stirring blade structure for a vertical stirring device, comprising: 2. The stirring blade according to claim 1, further comprising: a lattice wing above the conical bottom paddle in which a vertical grid having a larger outer diameter than the paddle and a horizontal arm are combined. Item 2. The stirring blade structure of the vertical stirring device according to Item 1.