JP3197194B2 - Stirrer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stirrer for stirring and mixing a substance such as a high-viscosity fluid, a slurry-like substance, a powder, and the like. Alternatively, the present invention relates to a stirring device suitable for use as a mixer for various raw materials in the food industry.

[0002]

2. Description of the Related Art In the chemical industry and the food industry, a stirrer is often used for mixing or reacting substances such as high-viscosity fluids, slurry-like substances, and powders. In order to treat such a substance, an apparatus having a high mixing performance and a high heat transfer performance and a function that does not generate deposits, that is, a device having a self-cleaning function is often desired.

In addition, in the polycondensation reaction and the desolvation operation, in order to separate a volatile substance from a high-viscosity fluid, a function having a large gas-liquid boundary area and a high surface renewal speed is further required. For this reason, a stirrer having a self-cleaning function has been conventionally proposed as a device for treating a substance having a particularly high adhesiveness. Here, there are generally the following two types of self-cleaning methods.

In the first method, two or more rotating shafts are provided, and the stirrers attached to the two or more rotating shafts, and the stirrer and the inner wall of the container are relatively moved while maintaining a small clearance, thereby mechanically attaching the rotating shafts. It is intended to completely prevent the formation of kimono.

In the second method, the flow state of a substance to be handled is taken into consideration, and the generation of an adhered substance is suppressed by the shearing action of the fluid itself.

However, in the chemical industry and the like in recent years, the quality of products has been strictly pursued, and the properties of substances to be handled have been diversified. In many cases, there is an increasing demand for devices using the first method.

[0007] As a device according to the first method for preventing the formation of deposits by mechanical scraping, a device in which a multi-screw screw is meshed, and Todd, DB et al.
ng.Progr.Vol.65, P.84 (1969), a paddle with a spindle-shaped cross section (convex lens-shaped cross section) or a paddle with a pseudo-triangular cross section Shaft agitators are known.

FIG. 3 shows an example of such a stirring device. The stirrer shown in FIG. 3 is arranged in parallel in a cylindrical container 11 and has two rotating shafts 121 and 131 driven to rotate at the same speed in the same direction.
1, a plurality of paddles 23, 24 having a spindle-shaped cross-sectional shape with a central portion swelling and bulging at both ends and having a radius of curvature represented by the following equation 1.
……, 33, 34 …….

[0009]

(Equation 1)

These paddles 23, 24..., 33, 3
4 are round shafts 121, 1 of rotating shafts spaced apart in the axial direction.
31. Each paddle 23, 24 ... 3
The scrapers 42 ', 43',... Having a pseudo-triangular cross section whose outer surface coincides with the outer peripheral surface of the paddle and having a length substantially corresponding to the interval between adjacent paddles are provided at the distal end portions of 3, 34.
Are mounted in parallel with the round shafts 121 and 131 of the rotating shaft.

Further, between adjacent paddles, shaft covers 122 and 132 having a pseudo-rectangular cross section having a round cross section and having an outer peripheral surface coinciding with the outer peripheral surface of the paddle are mounted.

In the agitating device thus constructed, the peripheral surfaces of the scrapers 42 ', 43',..., 52 ', 53',. Therefore, all surfaces in the container 11 can be completely completely mechanically cleaned.

[0013]

In a conventional apparatus, a screw screw provided in a container, a spindle shape,
A stirrer such as a paddle occupies a large volume through a pseudo-triangular cross section, and the effective volume of the container excluding the stirrer is several percent to 6%.
There was a problem that it was limited to 0%.

As a result, the total volume of the stirrer must be increased with respect to the charged amount of the substance to be treated, and the cost is high, so that practical application is sometimes difficult. When the time is long, the total volume of the apparatus with respect to the processing amount becomes enormous, which is a fatal disadvantage in terms of the apparatus cost.

In addition, this type of apparatus has a drawback that the stirring power is large and it is difficult to remove the heat of stirring, or the quality of the product is deteriorated due to heat deterioration and coloring due to heat generated by shearing. For example, in the stirring device of FIG. 3 described above,
, 52 ', 53',..., The fluid that has entered between the front surface of the container and the inner wall of the container is subjected to a large shearing and compressing action due to the movement of the scraper, so that there is a disadvantage that power consumption is increased.

The present invention solves such a problem in the conventional stirring apparatus, and achieves an increase in the effective volume ratio without impairing the self-cleaning function.
It is an object of the present invention to provide a stirring device with low power consumption.

[0017]

In order to solve the above-mentioned problems, the present invention comprises a plurality of rotating shafts arranged in a cylindrical container in parallel and driven to rotate in the same direction at the same speed; The following configuration is employed in a stirrer including a plurality of paddles each having a spindle-shaped cross-sectional shape which is fixed to each rotating shaft so as to be displaced from each other by approximately 90 degrees and whose central portion is bulged and whose both ends are sharp.

That is, in the agitator according to the present invention, the paddle is attached to the rotary shaft at an interval in the axial direction, and the outer surface of the paddle matches the outer peripheral surface of the paddle at the tip of the paddle . Fluid on the front is the axis center side
A scraper having a pseudo-triangular cross section in which the peripheral surface on the shaft center side is inclined toward the front surface in the rotational direction so as to flow on the peripheral surface and having a length substantially corresponding to the interval is mounted in parallel with the rotational shaft.

Further, a shaft cover having a pseudo-rectangular cross section with a round cross section and an outer peripheral surface coinciding with the outer peripheral surface of the paddle is mounted between the adjacent paddles.

The paddle used in the stirring device according to the present invention is preferably formed so that the radius of curvature of the spindle-shaped cross-sectional shape given by D is given by the above-described equation (1).

In the stirring apparatus of the present invention having the above-described structure, the paddle and the scraper are moved in the container by the driving rotation of the rotating shaft, and the substance to be stirred in the container is stirred and mixed. The paddles are arranged at intervals in the axial direction of the rotation axis,
In addition, since the scrapers are also provided only at the paddle tips, they occupy a small volume in the container, thus increasing the effective volume ratio.

The movement of the paddle and the scraper causes the adjacent ones to move relatively close to each other, and the respective parts in the container are self-cleaned. In addition, with respect to the inner peripheral surface of the scraper, the fluid near the inner wall of the container flows on the inner peripheral surface of the scraper as the scraper moves, and the adhesion and stagnation can be prevented by the shearing action of the fluid itself.

In addition, in the stirring device according to the present invention , the fluid on the front surface is rotated by rotating the peripheral surface on the shaft center side of the scraper.
Since it is inclined toward the front in the rotation direction so as to flow on the shaft center side peripheral surface, the fluid surrounded by the scraper front surface and the container inner wall is rotated along the shaft center side peripheral surface by the rotation of the scraper. By making it easier to flow, power can be reduced.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a stirrer according to the present invention will be described in detail with reference to the embodiments shown in FIGS. In the following embodiments, the same components as those of the conventional apparatus shown in FIG. 3 are denoted by the same reference numerals for simplification of description.

As shown in FIGS. 1 and 2, two rotating shafts 12 and 13 are supported in a container 11 in parallel with each other, and each of the rotating shafts 12 and 13 is driven by a driving source (not shown). As shown by arrows in the drawing, the motors are driven to rotate in the same rotational direction and at the same rotational speed in synchronization with each other.

The inner wall of the container 11 has rotating shafts 12 and 13
Has a cocoon-shaped cross-section that connects two cylindrical walls 111 and 112 each having a center at the center. Also, the rotating shaft 1
Reference numerals 2 and 13 denote round shafts 121 and 131, respectively, and shaft covers 122 and 13 having pseudo-square cross sections provided on the outer periphery thereof.
2 (see FIG. 2).

A plurality of paddles 21 to 26 are fixed to the rotating shaft 12 at predetermined intervals. Each paddle 21-
26 is formed in a thick plate shape having a spindle-shaped cross section with a bulged central portion and sharp ends, and when its diameter is D, the radius of curvature is formed so as to be a value represented by the above-described equation (1). ing.

Each of the paddles 21 to 26 is attached to the rotating shaft 12 along a plane orthogonal to the rotating shaft 12.
And paddles 21 to adjacent to each other in the axial direction of the rotary shaft 12.
Reference numeral 26 denotes a state in which the phase is shifted by 90 degrees around the axis.

The tips of the paddles 21 to 26 can be opposed to the cylindrical wall 111 of the container 11 or the corresponding paddles 31 to 36 to be described later with a slight clearance depending on the rotational angle position. The dimensions are selected.

On the other hand, a plurality of paddles 31 to 36 having a spindle-shaped cross section are similarly fixed to the rotating shaft 13. Each of the paddles 31 to 36 is located at the same axial position corresponding to the paddles 21 to 26, respectively.
The rotation axis 1 is shifted 90 degrees from each of the rotation axes 1 to 26.
3 attached.

The tip of each of the paddles 31 to 36 is separated from the cylindrical wall 112 of the container 11 or the corresponding paddle 21 by a slight clearance depending on the rotational angle position.
~ 26.

Further, the tips of the paddles 21 to 26 and 31 to 36 correspond to the cross-sectional shapes of the tips, respectively.
Further, scrapers 41 to 46 and 51 to 56 having a pseudo-triangular cross section inclined forward in the rotation direction are fixed in parallel with the rotation shafts 12 and 13. Each scraper 41-46, 51-5
The distal end face 6 is opposed to the adjacent paddles 21 to 26, 31 to 36 with a slight clearance in the axial direction.

Since the scrapers 41 to 46 and 51 to 56 have the same configuration, the scrapers provided on the paddle 23 will now be described in detail. As a representative, a total of four scrapers 43 are mounted on both the both end surfaces of the paddle 23. The front ends of the paddles 23 on both sides can be opposed to the side surfaces of the paddles 32 and 34, respectively.

The leading edge of each scraper 43 is located on the same line as the corresponding tip of the scraper 43, so that the leading end of each scraper 43 is separated from the tip of the scraper 43 by a slight clearance according to the rotational angle position of the rotating shaft 12. It can face a cylindrical wall 111 of the container 11 or a shaft cover 132 having a surface continuous with the paddle 33.

Also, as shown in FIG.
The scrapers 52 and 54 attached to the adjacent paddles 32 and 34 are inserted between the shaft cover 122 and the shaft cover 122 in accordance with the rotation. When the scrapers 52 and 54 are inserted, the peripheral surface of the scraper 43 on the shaft center side is formed. And scrapers 52, 5
The dimensions are selected so that the peripheral surface of No. 4 is in contact with the peripheral surface on the shaft center side at a fixed interval.

In such a stirring device, the substance to be stirred is introduced into the container 11 from an inlet (not shown),
The paddles 21 to 26, 31 are driven and rotated by the paddles 21 to 26, 31.
To 36 and the scrapers 41 to 46 and 51 to 56 are moved by the stirring action, and then taken out from an outlet (not shown).

Here, as can be seen from the sectional view of FIG. 2, the volume occupied by the rotating shafts 12, 13 and the scrapers 41 to 46, 51 to 56 is small, and the paddles 21 to 26, 31 to 3 are small.
6 are also installed at intervals, so that the effective volume ratio in the container 11 can be greatly increased as compared with a conventional self-cleaning type stirring device.

In the illustrated example, the effective volume is 70 to 75% of the total volume. It is to be noted that the effective space ratio can be further increased by increasing the mounting intervals of the paddles 21 to 26 and 31 to 36 as necessary and increasing the length of the scrapers 41 to 46 and 51 to 56 accordingly.

On the other hand, each part in the container 11 is self-cleaned by the following cleaning action simultaneously with the stirring action. That is, the inner walls of the container 11 are paddles 21 to 2
6,31-36, and scrapers 41-46,5
The cleaning is performed by the leading edge portions 1 to 56 moving close to each other.

Also, paddles 21 to 26 and paddles 31 to 3
The curved peripheral surfaces of 6 are cleaned by their tips moving closer together. In addition, paddle 2
The planar side surfaces of 1-26, 31-36 and the tip surfaces of the scrapers 51-56, 41-46 facing each other are cleaned by moving close to each other.

For example, the plane side surface of the paddle 22 moves relatively close to the tip surfaces of the scrapers 51 and 53, and their opposing surfaces are cleaned from each other. Further, the outer peripheral surfaces of the scrapers 41 to 46, 51 to 56 are mutually cleaned as the scrapers 41 to 46, 51 to 56 move their tips and outer peripheral surfaces close to each other.

Also, the scrapers 41 to 46, 51 to 56
When the scraper moves along the inner wall of the container 11, the fluid on the front surface of the scraper flows on the peripheral surface on the shaft center when the scraper moves along the inner wall of the container 11, and is thus cleaned by the shearing action of the fluid itself.

Paddle 21 by rotation of rotating shafts 12 and 13
26, 31-36, scrapers 41-46, 51-5
By the relative movement of 6, all surfaces in the container 11 can be completely cleaned.

The stirring device shown in FIG. 3 has a drawback that the fluid entering between the front surface of the scraper and the inner wall of the container is subjected to a large shearing and compressing action due to the movement of the scraper, so that the power consumption is increased. In the stirrer in the form, the peripheral surfaces of the scrapers 41 to 46 and 51 to 56 on the shaft center side are inclined in the rotation direction so that the fluid surrounded by the scraper front surface and the inner wall of the container can easily flow along the shaft center side peripheral surface. , Power can be reduced.

As described above, the present invention has been specifically described based on the illustrated embodiments. However, the present invention is not limited to these embodiments, and specific structures within the scope of the present invention shown in the claims are set forth. Needless to say, various changes may be made to the configuration.

For example, although two rotating shafts are provided in the above embodiment, the present invention is not limited to two rotating shafts.
It is also possible to provide three or more.

[0047]

As described above, in the stirrer according to the present invention, the outer surface of the paddle attached to the rotary shaft at an axial interval is aligned with the outer peripheral surface of the paddle so that the outer surface of the paddle is aligned with the outer surface of the paddle. According to this stirring device, a scraper having a pseudo-triangular cross-section inclined toward and having a length substantially corresponding to the above-mentioned interval is mounted in parallel with the rotation axis, without impairing the self-cleaning function. Can be increased, and power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a stirring device according to an embodiment of the present invention.

FIG. 2 is a transverse sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view similar to FIG. 2, showing a conventional stirring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Container 12,13 Rotation axis 21-26,31-36 Paddle 41-46,51-56 Scraper 111,112 Cylindrical wall 121,131 Round shaft 122,132 Shaft cover

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-136480 (JP, A) JP-A-4-99222 (JP, U) JP-B 5-46251 (JP, B2) 54806 (JP, Y2) Jikken Hei 6-12822 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01F ^7/ 00-7/32

Claims (1)

(57) [Claims] 1. A plurality of rotating shafts disposed in parallel in a cylindrical container and driven to rotate in the same direction and at the same speed, and fixed to each of the rotating shafts by being shifted by about 90 degrees around the respective axes. In a stirring device comprising a plurality of paddles having a spindle-shaped cross-sectional shape with a bulged central portion and both ends being sharpened, the paddles are attached to the rotary shaft at intervals in the axial direction, and at the tip of the paddle. The outer surface coincides with the outer peripheral surface of the paddle, and the fluid on the front surface flows on the peripheral surface on the shaft center side by rotation.
A shaft center side peripheral surface forms a pseudo-triangular cross section inclined toward the rotation direction front surface, and a scraper having a length substantially corresponding to the interval is attached in parallel with the rotation axis, between the adjacent paddles. A stirrer, wherein a shaft cover having a rounded pseudo-square cross section and an outer peripheral surface coinciding with an outer peripheral surface of the paddle is mounted.