JPH0615026B2 - Stirrer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stirring device used for stirring reactors, tanks and the like, and more specifically, uses a magnetic force to rotate a stirring bar without mechanical coupling. It relates to a stirrer adapted to be driven.

[Conventional technology]

FIGS. 7 and 8 show a conventional stirring device that uses magnetic force to rotate the stirring bar without mechanical coupling.
The figure will be described.

FIG. 7 is a vertical cross-sectional view of a stirring device using a rod-shaped magnetic stirrer, in which the upper part of the partition wall 1 forming a part of the vessel wall of the sealed container corresponds to the inside of the container. The stirrer 2 is accommodated. In general, the inside of a container is filled with liquid chemicals or intermediate products that do not want to be contaminated from the outside, and is agitated for various unit operations such as chemical reaction, dissolution, crystallization and mixing. . The magnetic stirrer 2 is formed by coating the entire rod-shaped permanent magnet 3 with a plastic protective layer 4, and both ends of the rod-shaped permanent magnet 2 are magnetized with different magnetic poles. On the other hand, partition wall 1
A frame 6 for mounting the motor 5 is fixed to the partition wall 1 on the outer side (downward in the drawing), and a flange 7 of the motor 5 and the frame 6 are fastened by a bolt nut (not shown).

An iron yoke 9 is fixed to the main shaft 8 of the motor 5, and a rod-shaped permanent magnet 1 is provided on the side of the yoke 9 facing the partition wall 1.
0 is fixed to the partition wall 1 through a slight space. The rod-shaped permanent magnet 10 on the driving side is also magnetized to different magnetic poles at both ends, and the permanent magnet 10 on the driving side and the permanent magnet 3 of the stirrer are in a state where different magnetic poles are attracted to each other. It opposes via the partition 1.

The motor 5 is operated at a variable speed by a control unit (not shown), and the magnetic stirrer can rotate in synchronization. Therefore, when the motor 5 is energized,
The permanent magnet 10 on the driving side is rotated, and the magnetic force of the permanent magnet 10 causes the magnetic stirrer 2 housed inside the partition wall 1 to rotate synchronously, so that the liquid around the magnetic stirrer 2 is A flow as indicated by arrow A is generated by receiving a centrifugal force from the magnetic stirrer 2, and the liquid in the container is suitably stirred.

The plastic protective layer 4 is appropriately selected from various materials such as polypropylene / fluorine resin or corrosion resistant alloy in consideration of the properties and temperature of the liquid in the container.

FIG. 8 is a longitudinal sectional view showing another conventional example, which is used as a relatively large stirring device. In the figure, the drive mechanism fixed to the outside of the partition wall 1 is shown in FIG.
The stirring bar 2 is formed at a position where the magnet portion 11 and the paddle portion 12 are separated from each other, although it is almost the same as the conventional example in the figure. That is, an annular magnet portion 11 is formed at the end of the stirrer 2 on the side where the drive mechanism is fixed, and in the middle of the shaft 19 extending upward from the center of the upper portion of the magnet portion 11, A paddle portion 12 formed by fixing a plurality of paddles 21 to the disc 20 is formed. The ring-shaped magnet part 11 is formed by fixing a similar ring-shaped iron plate 16 to the upper surface of a ring-shaped copper plate 15 and further covering the whole by a protective layer 17 made of stainless steel which is a corrosion-resistant material. Is a journal 14 corresponding to a round bar 13 as a radial bearing fixed to the partition wall 1.

The magnet portion 11 is configured such that an eddy current is generated in the copper plate 15 by the rotation of the permanent magnet 10 on the driving side to generate a rotational torque, which is not synchronized with the rotational speed of the permanent magnet 10. However, an annular permanent magnet may be provided instead of the copper plate 15 and used as a synchronous coupling. The permanent magnet 10 on the driving side is a disk-shaped permanent magnet 10 having different magnetic poles alternately magnetized in the circumferential direction as shown in FIG. The stirring device shown in FIG. 8 is
Since the paddle portion 12 can be formed at any position in the container, a desired stirring state can be obtained.

[Problems to be Solved by the Invention] With the stirring device, external foreign matter is mixed into the handling liquid and contaminated, or harmful handling liquid flows out to the outside due to the magnetic force as described above. It can be prevented by a stirring device of a stirring type. However, since the stirrer rotates while being attracted by the magnet on the drive mechanism side, when normal stirring operation is performed, rubbing is performed between the end surface of the stirrer and the partition wall 1. As a result, abrasion powder may be generated from the protective layer 4 of the stirrer or the partition wall 1 and foreign matter may be mixed into the handled liquid. In particular, in the case of a stirrer in which the protective layer 4 is made of plastic, the surface of the protective layer 4 is abraded even if the handling liquid contains a solid matter.

Therefore, the handling liquid is contaminated by the abrasion powder generated by the stirring bar itself, and the quality of the handling liquid is deteriorated due to the inclusion of the abrasion powder, and various obstacles are given in the subsequent steps. It will be. Therefore, in the manufacturing process of medicines, foods, etc., a removal process for separating such abrasion powder may be separately provided. However, when the slurry is used as the handling liquid, it is difficult to selectively remove only the abrasion powder, and it is unavoidable to manufacture a low-quality product.

The present invention has been made in view of the above-mentioned current situation, and in a stirrer in which magnetic force (magnetic force) is used, the stirrer is rotationally driven without mechanical coupling. Is to provide a device for suppressing the generation of abrasion powder due to sliding contact between the partition wall and the partition wall, and the present invention is
It is an object of the present invention to provide a stirring device which does not wear even in a slurry and can be stably used for a wide range of liquids.

[Means for solving problems]

The present invention relates to a drive mechanism that is fixed to the outside of a partition wall and that generates a rotating magnetic field, and that is disposed inside the partition wall and is magnetically rotated by the drive mechanism while transmitting a rotational force to the drive mechanism. In a stirrer equipped with a stirrer that is not mechanically connected to each other, the sliding parts of the stirrer and the partition wall are each made into a smooth surface, and one of these two smooth surfaces is provided. It is a stirring device in which a groove for generating a dynamic pressure for generating a dynamic pressure is generated on a surface of the fluid which is present in the sliding portion.

In the present invention, hysteresis or eddy current can be used in addition to magnetic attraction as a principle of magnetically rotating the stirrer, and the smooth surface of the sliding portion has a flat surface, a spherical surface, Any shape such as a conical surface or a cylindrical surface can be used as long as it is a surface obtained when rotating around the rotation axis of the stirrer. Further, as the groove shape for generating the dynamic pressure, known groove patterns such as spiral shape and herringbone shape can be used.

[Action]

In the present invention, for generating dynamic pressure such as a spiral pattern or a herringbone pattern on either one of the stirrer-side surface and the partition-side surface forming the sliding portion between the stirrer and the partition wall Since the groove is formed, when the stirring bar rotates under the influence of the rotating magnetic field formed by the drive mechanism,
A fluid film is formed on the sliding portion by a groove for generating a dynamic pressure, and the stirrer and the partition wall rotate without substantially contacting each other. The thickness of the fluid film formed on the sliding portion is extremely thin, though it depends on the viscosity of the fluid, so that the solid matter having a large particle size does not flow into the clearance.

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of a stirring device showing an embodiment of the present invention. In the figure, the lower part of the partition wall 1 is generally a portion corresponding to the outside of the container and has the same structure as that in FIG. That is, a frame 6 for fixing the motor 5 is provided on the outer side of the partition wall 1 forming a part of the wall surface of the tank, the reaction container, or the like.
Is fixed, and the flange 7 of the motor 5, which is supplied with power from a control unit (not shown) and is capable of variable speed operation, is fixed to the frame 6. An iron yoke 9 is fixed to the tip of the main shaft 8 of the motor 5, and a disk-shaped permanent magnet 10 is fixed to the side of the yoke 9 facing the partition wall 1. The surface (upper surface in FIG. 1) of the permanent magnet 10 is magnetized so that different magnetic poles are arranged alternately in the circumferential direction (9th embodiment).
See figure). Here, when the motor 5 is energized, the permanent magnet 10
Rotates, and a magnetic field that rotates parallel to the partition wall 1 is formed.
On the other hand, the upper side of the partition wall 1 corresponds to the inside of the container, and the surface thereof is a smooth flat surface 23. The waviness of the smooth surface 23 is finished within 5 μm over the entire sliding portion, and the surface roughness is 1 μm or less.

On the other hand, regarding the stirrer 2 located above the partition wall 1, that is, on the side where the liquid to be stirred is contained, the paddle portion 12 is provided in the middle of the shaft 19, and the shaft 19 is provided.
The magnet portion 11 is fixedly provided at the end of the partition wall 1 side. The magnet part 11 is formed by covering an annular copper plate 15 and an annular iron plate 16 fixed to the upper part thereof with a protective layer 17 of stainless steel so as to rotate by an eddy current. A ceramic thrust plate 24 is fixed to the lower end surface. The thrust plate 2
The surface of 4, that is, the lower end surface is a surface that slides on the partition wall 1 and is finished to be a smooth flat surface that is approximately the same as the surface of the partition wall 1. However, the movement as shown in FIG. A spiral groove (black-painted spiral portion) 25 for generating pressure is formed. A white spiral portion 26 in FIG.
Is a land where a smooth plane is left. In addition, the pressure equalizing portion 27 is provided at the center and the spiral groove 25 is formed.
It is the same groove part as. The groove depth of the spiral groove 25 is 3 to
It is 50 μm, and its smooth surface is finished by shot blasting, electric discharge machining, etching, etc. The surface is rougher than the land 26. Even if it has a satin finish, dynamic pressure is generated. The land 26 of FIG. 2 and the satin-finished groove portions 25 and 27 may be completely opposite to each other, and a black portion may be a smooth land and a white portion may be a groove portion. In the figure,
Reference numeral 28 denotes the rotation direction of the stirrer 2. When the motor 5 is energized and the permanent magnet 10 rotates in the direction of arrow 28, an eddy current is generated in the magnet portion 11 of the stirrer 2, and similarly in the direction of arrow 28. Then, the magnet portion 11, that is, the stirrer 2 is rotated, and the liquid is caused to flow by the paddle 21 in the direction of arrow A to be stirred. At this time, the stirrer 2 is not only given a rotational force by the drive mechanism mainly composed of the motor 5 and the permanent magnet 10, but also is attracted by the magnetic force of the permanent magnet 10 and the self-weight of the stirrer 2. Then, the spiral groove 25 for generating the dynamic pressure forms a fluid lubricating film between the thrust plate 24 and the partition wall 1 of the ceramics, and the thrust plate 24 and the partition wall 1 are pressed against each other. Perform relative movement without substantially contacting each other, and as a result, no abrasion powder is generated from the sliding contact portion between the thrust plate 24 and the partition wall 1. Here, the groove for generating the dynamic pressure may be formed on the partition wall 1 side. In the embodiment of FIG. 1, when the groove is formed on the partition wall 1 side, the pattern seen from above the partition wall 1 is shown in FIG. The arrow 28 in the rotating direction of the stirrer is in the opposite direction.

In the embodiment shown in FIGS. 1 and 2 above,
Not only the stirrer 2 and the partition wall 1 rotate in a non-contact state, but also the resistance in the sliding portion between the stirrer 2 and the partition wall 1 becomes extremely small, so that the magnetic rotational force of the drive mechanism can be effectively used. It can be converted into stirring power.

In FIG. 1, the copper plate 15 that generates an eddy current can be used as a synchronous magnet coupling instead of a permanent magnet, or can be replaced with a hysteresis material. Further, as the drive mechanism, the permanent magnet 1
0 may be an electromagnet, or the stirrer may be directly driven by a coil group that generates a similar rotating magnetic field. Also, by detecting the rotation speed of the stirrer 2,
The operation may be performed at a desired rotation speed.

FIG. 3 is a view similar to FIG. 1 showing another embodiment, but in the stirrer 2 above the partition wall 1, the annular copper plate 15 of FIG. 1 is replaced by an annular permanent magnet 29. Only thing is different.

That is, the permanent magnet 29 embedded in the magnet portion 11 of FIG. 3 is an annular flat plate as shown in the plan view of FIG. 4, and has different magnetic poles alternately magnetized in the circumferential direction. There is. In this case, the number of poles is the permanent magnet 1 on the drive mechanism side.
It matches the zero pole number. Further, on the surface of the thrust plate 24, a groove for generating a dynamic pressure is formed as in FIG.

On the other hand, regarding the lower side of the partition wall 1, the surface of the permanent magnet 10 made of a ferrite magnet, that is, the surface 30 facing the partition wall 1 is finished to be a smooth flat surface, and the surface 30 of the permanent magnet 10 is also finished. Surface 31 of the partition wall 1 facing the
Is also finished to have a smooth flat surface like the back surface (surface facing the stirrer 2), and a groove for generating dynamic pressure is formed on the surface 31 side of the partition wall 1. The yoke 9 and the main shaft 8 of the motor 5 are connected by a pin 32 so as to transmit only the rotational force of the motor 5 so that the thrust force of the permanent magnet 10 is not applied to the motor 5. . At the same time, the surface 30 of the permanent magnet 10 adheres parallel to the surface 31 of the partition wall 1 regardless of the main shaft 8 of the motor 5.

Therefore, when the motor 5 is energized, the permanent magnet 10 and the partition wall 1
The dynamic pressure of the fluid is generated in the sliding portion between the sliding member and the sliding portion between the thrust plate 24 and the partition wall 1, the sliding resistance in these sliding portions is extremely small, and the thrust load applied to the motor 5 is reduced. The magnetic gear narrows.

5 and 6 are drawings showing another embodiment of the present invention, wherein FIG. 5 is a vertical sectional view and FIG. 6 is a plan view of a stirrer.

In FIG. 5, the through hole 4 is formed in the wall 40 of the tank or the reactor.
1 is bored, the drive mechanism 42 is fixed by a bolt (not shown), and a resin 43 is filled between the device wall 40 and the drive mechanism 42 for sealing. The drive mechanism 42 fixes a stator 44, which is a stack of a number of sheet coils in which conductor coils are coated with plastics, to a cover 45, and a sheet 46 in which a sensor for detecting the magnetic pole of the stirrer 2 is embedded above the stator 44. It is fixed, and a ceramic flat plate 47 is fixed on the uppermost portion, and its control unit is not shown.
Here, the ceramic flat plate 47 corresponds to the partition wall 1 in the above-mentioned embodiment, and is made of a ceramic material of which the rotating magnetic field generated in the stator 44 formed by stacking sheet coils is easily transmitted to the stirrer 2 side. Selected. For example, ceramics in which a small amount of beryllium or a beryllium compound is added to silicon carbide is preferable, but silicon carbide, silicon nitride, alumina or the like may be used.

The stirrer 2 comprises a disc-shaped magnet portion 11 and a stirring blade 48 formed on the upper surface thereof. The magnet portion 11 includes a rotor 49 of a disc-shaped ceramic, a permanent magnet 29, an iron plate 16 and a protective layer. A recess 50 for burying 17 is formed, and the blade 48 and the rotor 49 are integrally formed by ceramics. A sliding portion is formed by the bottom surface 51 of the rotor 49 and the surface 52 of the ceramic flat plate 47 on the drive mechanism 42 side.
Reference numerals 1 and 52 are finished to be smooth flat surfaces, and a groove for generating dynamic pressure is formed on either one of the surfaces.

The groove for generating dynamic pressure has a spiral shape as shown in FIG. 2, and the groove depth, surface roughness, and waviness are the same as in the above-mentioned embodiment.

FIG. 6 is a plan view of the stirrer 2 as seen from above, and four stirring blades 48 are radially formed, and a circular rotor 49 has an upper surface on which a fan-shaped blade is formed between adjacent blades. The protective layer 17 is formed. Although not shown, a fan-shaped iron plate 16 and a permanent magnet 29 are similarly embedded below the protective layer 17. In FIG. 6, the magnetized state of the permanent magnet 29 is shown for convenience. . The protective layer 17 is made of a corrosion-resistant material such as plastic or stainless steel, but wear resistance is further improved by using ceramics as in the rotor 49.

〔The invention's effect〕

The present invention, in a stirring device in which a stirring bar is magnetically rotated, smoothes the two surfaces forming the sliding portion between the stirring bar and the partition wall, and makes one of these two surfaces smooth. By forming a dynamic pressure generating groove that generates a dynamic pressure in the fluid interposed in the sliding part, when the stirrer rotates, a fluid lubricating film is formed on the sliding part by the action of the dynamic pressure generating groove. Since the stirrer and the partition wall are relatively rotated without being substantially in contact with each other, abrasion powder is not generated due to the contact between the stirrer and the partition wall. Furthermore, since the stirrer does not come into contact with the partition wall when rotating, the loss in the sliding portion is extremely small.
Therefore, in this type of stirring device having a smaller rotation torque than the shaft-penetrating stirring device, the magnetic force generated by the drive mechanism can be effectively converted into the rotation torque of the stirrer.
Strong stirring can be performed.

Therefore, according to the stirrer of the present invention, there is no generation of abrasion powder due to the rubbing between the stirrer and the partition wall, so that the liquid is not contaminated. Further, since the sliding portion between the stirrer and the partition wall is in surface contact, stable operation can be performed by the damping effect while the stirrer is rotating.

In the present invention, if the two surfaces forming the sliding portion are made of ceramics, dynamic pressure can be effectively generated, and the abrasion resistance is excellent, so that even a slurry is used. Can be stirred without any problems.

[Brief description of drawings]

1 is a vertical sectional view showing an embodiment of the present invention, FIG. 2 is a schematic view of a groove for generating a dynamic pressure of a sliding portion, FIG. 3 is a vertical sectional view showing another embodiment, and FIG. FIG. 5 is a schematic view showing the state of magnetization of the permanent magnets of the stirrer in FIG. 3, FIG. 5 is a longitudinal sectional view showing another embodiment, and FIG. 6 is a plan view of the stirrer in FIG. 7 and 8 are longitudinal sectional views of a conventional example, and FIG. 9 is a plan view showing the magnetized state of the magnet on the drive mechanism side in FIG. 1 ... Partition, 2 ... Stirrer, 5 ... Motor, 8 ... Spindle, 9 ... Yoke, 10 ... Permanent magnet, 11 ... Magnet part, 12 ... Paddle part, 15 ... Copper plate, 16 …… Steel plate, 17 …… Protective layer, 19 …… Shaft, 20 …… Disk, 21 …… Paddle, 23 …… Sliding surface (flat), 24 ・ ・ ・
… Thrust plate, 25 …… Spiral groove, 26 …… Land, 27 …… Surface pressure part, 30 …… Plane, 31 …… Surface, 4
0 ... Instrument wall, 41 ... Through hole, 42 ... Drive mechanism, 43
…… Resin, 44 …… Stator, 45 …… Cover, 46 ……
Sheet, 47 ... Plate, 48 ... Stirrer, 49 ... Rotor, 50 ... Recess, 51 ... Bottom, 52 ... Surface.

 ─────────────────────────────────────────────────── ─── 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 (1)

[Claims] 1. A drive mechanism fixed to the outside of a partition wall to generate a rotating magnetic field, and a drive mechanism disposed inside the partition wall and magnetically rotated by the drive mechanism, the drive mechanism generating a rotational force. In a stirrer equipped with a stirrer that is not mechanically coupled for transmission, the sliding parts of the stirrer and the partition wall are each made into a smooth surface, and either one of these two smooth surfaces is provided. A stirrer characterized in that a groove for generating a dynamic pressure for generating a dynamic pressure in a fluid interposed in the sliding portion is formed on the surface of the stirrer.