JPH0615025B2 - Stirrer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stirrer used for stirring reactors, tanks and the like, and more particularly to a stirrer magnetically rotated from the outside of a container.

[Conventional technology]

A conventional magnetic stirrer will be described with reference to FIGS. 6 and 7.

FIG. 6 is a sectional view of a rod-shaped stirrer, in which reference numeral 1 is a permanent magnet made of ferrite and its shape is cylindrical. Both ends of the permanent magnet 1 are magnetized differently. The outer surface of the permanent magnet 1 is covered with a protective layer 2 of fluorine resin over the entire surface. The permanent magnet 1 is not limited to ferrite, but is also used in rare earth-based permanent magnets, alnico-based magnets, etc. because it has low corrosion resistance to chemicals and mechanical strength, so it is coated with fluorine resin or polypropylene depending on the purpose of use. Is common.

FIG. 7 (a) is a vertical cross-sectional view of a turbine-type stirrer, and FIG. 7 (b) is a plan view (a part of which shows a cross-section). In the figure, the permanent magnet 1 is an annular disc, and the whole of the permanent magnet 1 is covered with a protective layer 2 of fluorine resin. Further, a plurality of sheets formed integrally with the protective layer 2 are provided on the upper portion. A stirring blade 3 is provided. Reference numeral 4 is an arrow indicating the rotating direction of the stirrer, and reference numeral 5 is an alternate long and short dash line indicating the position of the sectional view of FIG. 7 (a). This permanent magnet 1 is magnetized in a ring with four poles,
A large rotating torque is obtained.

In order to magnetically rotate the stirrer shown in FIG. 6, a rod-shaped permanent magnet is usually rotated by a motor to synchronize the rotation of the stirrer. However, when performing strong stirring, the permanent magnet is used. An electromagnet that can obtain a larger magnetic force may be used. In order to rotate the stirrer shown in FIG. 7, a disk-shaped permanent magnet magnetized to 4 poles is fixed to the drive shaft of the motor, and the stirrer is housed outside the container. This is done by energizing the motor.

[Problems to be solved by the invention]

The conventional stirrer described above has the protective layer 2 in contact with the partition wall.
Was gradually abraded by friction with the partition walls, and abrasion powder generated at that time was sometimes mixed in the liquid. The purpose of stirring using a stirrer to which a magnet is applied is not only to stir the liquid in the closed container, but also to prevent foreign matter from being mixed into the liquid from the outside. In particular, in the manufacturing process of pharmaceuticals, foods, soft drinks, etc., the substances to be handled must always be operated in a controlled environment, and even if the abrasion powder from the stirring bar is mixed, it is ignored. I often cannot. When the abrasion powder is mixed in the liquid as described above, not only the quality of the product is deteriorated but also an undesired influence is exerted in a later step, and therefore a separation step for removing the abrasion powder must be provided in advance.

Therefore, the present invention aims to reduce the abrasion powder generated by friction in the stirrer of the type that is rotated by the magnetic force as described above, and the solid matter is contained in the stirred liquid. It is an object of the present invention to provide a stirrer that can be used even if it is contained, and can be used even under the condition of no liquid.

[Means for solving problems]

According to the present invention, in a stirrer rotated by a magnetic drive mechanism provided outside the partition wall, a part or all of the surface of the stirrer facing the partition wall is made of a ceramic member, and the ceramic member is provided. It is a stirrer in which a groove for dynamic pressure generation is formed on a surface of a member for generating a dynamic pressure in a fluid interposed in a sliding portion.

Here, the magnetic drive mechanism includes not only a mechanism that uses the attractive force of a magnet but also a mechanism that uses an eddy current and a mechanism that uses hysteresis.

[Work]

In the stirrer of the present invention, since the stirrer side is composed of a ceramic member having a large hardness in the sliding portion between the stirrer and the partition wall, no abrasion powder is generated from the stirrer side, and further, the ceramic member Since a groove for dynamic pressure generation is formed on the surface facing the sliding part of the, when the stirrer rotates, dynamic pressure is generated in the fluid interposed between the stirrer and the partition wall, and the stirring The child rotates substantially without contact with the septum.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a stirrer showing an embodiment of the present invention, in which 1 is an annular permanent magnet and 2 is a plastic protective layer covering the permanent magnet 1. A plurality of agitating blades 3 are radially integrally formed on the plastic protective layer 2. On the other hand, a ceramic disk 5 is bonded below the permanent magnet 1, and the permanent magnet 1 is sealed by the plastic protective layer 2 and the ceramic disk 5. The permanent magnet 1 is magnetized into a plurality of magnetic poles along an annular shape as in the conventional example shown in FIG. FIG. 2 is a front view showing the surface 6 of the disk 5 of the ceramic shown in FIG. 1. The surface 6 is finished to be smooth, and a plurality of spiral grooves 7 are formed in the central portion thereof. To the outer peripheral edge. The white background portion 9 excluding the spiral groove 7 on the surface 6 and the pressure equalizing groove 8 at the center is a land, and is finished so that the undulation is ± 3 μm or less over the entire surface. 7 is land 9
It is about 3 to 50 μm deeper than that. Further, the pressure equalizing groove 8 in the central portion has the same groove depth as the spiral groove 7, but it may have a groove depth larger than that, or may have a surface having the same height as the land 9.

When the stirrer rotates in the direction of arrow 4, a dynamic pressure of the fluid is generated between the stirrer and the partition 11 (see FIG. 1), and the stirrer rotates without substantially contacting the partition 11. Here the partition wall 11
It is desirable that the surface facing the sliding part is also smooth and has a large electric resistance and is a hard material. Further, as a material forming the disk 5 of ceramics, known ceramics such as silicon carbide, silicon nitride, alumina and titanium nitride can be used. Further, the same ceramics can be used as the material forming the partition wall 11.

3 (a) to 3 (c) are drawings showing another embodiment.
FIG. 1 (a) is a longitudinal sectional view, in which the permanent magnet 1 and the ceramic flat plate 5 are annular flat plates having the same radius, and the upper part of the protective layer 2 made of a resin such as fluorine resin or polycarbonate is shown in FIG. Similarly, the stirring blade 3 is integrally formed.

FIG. 3 (b) is a front view seen from the upper part of the stirring blade.
In the stirring blade, the main stirring blades 3 and the auxiliary stirring blades 3'are alternately arranged at the same intervals so that stronger stirring is performed.

FIG. 3 (c) is a front view showing the surface of the annular ceramic flat plate 5, and the ceramic flat plate 5 is a doughnut-shaped plate having a hollow 12 at the center.
As in the embodiment shown in the figure, it comprises a smooth land 9 and a spiral groove 7 for generating a dynamic pressure which is machined deeper than the land 9 by 3 to 50 μm, and is provided in a portion corresponding to the pressure equalizing groove 8 in the above-mentioned embodiment. There is no ceramic material.

In this embodiment, the central part is hollow,
The purpose is to reduce the amount of expensive ceramics used and to reduce the weight of the entire stirring bar. Also in this embodiment, since the permanent magnet 1 is sealed by the ceramic flat plate 5 and the plastic protective layer 2, the chemical resistance is high.

4 (a) and 4 (b) are a plan view and a vertical sectional view showing an embodiment of a stirrer suitable for stirring slurry, in which the stirring blade 3 is formed with a groove for generating a dynamic pressure. It is formed of ceramics integrally with the plate 5, and the permanent magnet 1 includes the stirring blades 3,
A fan-shaped member 3 is embedded between the ceramic plates 5 in which grooves for generating dynamic pressure are formed, and the upper part is protected by a plastic protective layer 2. Fig. 4
In (a), a fan-shaped protective layer is a plastic protective layer, and the permanent magnet 1 is located therebelow. For the sake of convenience, FIG. 4 (a) shows how the embedded permanent magnet 1 is magnetized.

FIG. 4 (b) is a vertical cross-sectional view taken along the center line IV-IV of FIG. 4 (a), showing that the entire surface facing the partition wall (not shown) is formed of a ceramic member and has a structure with a large abrasion resistance. ing. In the embodiment of FIGS. 4 (a) and 4 (b), the sliding surface 6 of the ceramic facing the partition wall may be the one shown in FIG.

FIGS. 5 (a) and 5 (b) are vertical cross-sectional views of two different stirrer examples in which a positioning member is provided at the center of the stirrer to further stabilize the rotation of the stirrer. is there.

FIG. 5 (a) shows that a through hole 17 is formed at the center of rotation of the stirrer of the embodiment shown in FIG. 4, and a pin 13 made of a stable material such as a ceramic member or a hard plastic is inserted into the through hole 17. The tip of the pin 13 is fixed to the partition wall 11. The groove pattern for generating dynamic pressure on the bottom surface 6 of the stirrer in this embodiment is similar to that shown in FIG. 3 (c), and the dynamic pressure is retained by the land 9 on the inner peripheral edge. . In this embodiment, the head of the pin 13 has a diameter larger than that of the through hole 17, so that the stirrer can be operated even when it cannot be synchronized with the rotating magnetic field provided by the magnetic drive mechanism (not shown). It will be held in place.

FIG. 5 (b) shows a hemispherical recess 15 at the center of the bottom of the stirring bar.
On the other hand, the hemispherical concave portion 16 is also formed in
And the small spheres 14 are accommodated in the space formed by the two recesses 15 and 16 so as to suppress the radial deflection like the pin 13.
Others are all common to the embodiment of FIG.

〔The invention's effect〕

In the stirrer of the present invention, the sliding surface on the side of the stirrer facing the sliding portion between the stirrer and the partition wall is constituted by a ceramics member, and the surface of the ceramics member has a dynamic pressure applied to the fluid interposed in the sliding portion. By forming the groove for dynamic pressure generation that generates the stirrer, when the stirrer is rotationally driven by a magnetic drive mechanism that generates a rotating magnetic field provided outside the partition wall, the stirrer is pressed against the partition wall. When the stirrer rotates, the fluid flows along the groove for dynamic pressure generation toward the center of the stirrer due to the rotation of the stirrer, which causes the dynamic pressure to be generated in the sliding part. However, the stirrer rotates without substantially contacting the partition wall. Therefore, the amount of abrasion powder generated by the rubbing between the stirrer and the partition wall is substantially eliminated, which is suitable when it is desired to prevent contamination due to the inclusion of foreign matter. This is particularly useful in agitation operation during the manufacturing process of pharmaceuticals, foods, etc., and since there is no mixing of foreign matter in intermediate products and final products, the quality of each will be improved, and the process of removing foreign matter Can be omitted, so that the product yield can be increased, and at the same time, the process can be simplified.

Furthermore, in the present invention, if the stirring blade and the ceramics member in which the groove for dynamic pressure generation is formed are formed by the same ceramics member, the wear resistance of the stirrer is further improved and the slurry liquid is stirred. However, no abrasion powder is produced.

Further, the stirrer of the present invention is used in an extremely wide range of applications, because the dynamic pressure is generated in the sliding portion by the dynamic pressure generating groove regardless of whether it is in liquid or in gas. You can Also, as a means for rotating the stirrer, there is an advantage that a known magnetic driving means such as a synchronous coupling (permanent magnet-permanent magnet / electromagnet), a hysteresis coupling or an eddy current coupling can be used.

Further, in the stirrer of the present invention, in the rotating state, the space between the surface of the ceramics member in which the groove for generating the dynamic pressure is formed and the partition wall is held at an extremely narrow (several μm to several tens μm) interval. Therefore, there is no problem that the agitated liquid is stagnated within the interval and the uniform agitation is disturbed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a stirrer showing an embodiment of the present invention, FIG. 2 is a front view of a sliding surface of FIG. 1, and FIGS. 3 (a) to (c) are other embodiments. The longitudinal sectional view, the plan view and the front view of the sliding surface shown in FIGS. 4 (a) and 4 (b) are different from the plan view and the longitudinal sectional view showing another embodiment, and FIGS. 6 is a vertical sectional view of a conventional example, FIG. 7 (a) is a vertical sectional view of another conventional example, and FIG. 7 (b) is a plan view including a partial cross section thereof. Is. 1 ... Permanent magnet, 2 ... Protective layer, 3 ... Stirring blade, 5 ...
Ceramic disk, 7 ... spiral groove, 8 ... pressure equalizing groove, 9 ... land, 11 ... partition, 12 ... cavity, 13
...... Pin, 14 ... small ball.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sachi Chiba 4720 Fujisawa, Fujisawa, Kanagawa Prefecture, Ebara Research Institute, Ltd. (56) References JP-A-60-156538 (JP, A)

Claims (2)

[Claims] 1. A stirrer rotated by a magnetic drive mechanism provided outside the partition wall, wherein a part or all of the surface of the stirrer facing the partition wall is formed of a ceramic member. A stirrer characterized in that a groove for generating dynamic pressure is formed on a surface of a ceramic member to generate a dynamic pressure in a fluid interposed in a sliding portion. 2. The stirrer according to claim 1, wherein a recess or a through hole is formed at the center of rotation of the ceramics member.