DE202022105450U1 - Magnetic stirrer - Google Patents

Abstract

Magnetic agitator (1) with a stirring head (3), a containment shell (5) and a bearing pin (7), the bearing pin (7) being designed as a radial bearing section on the containment shell (5), the containment shell (5) having a drive section (9 ), in which a rotatable first magnet arrangement (11) is arranged, which is magnetically coupled to a second magnet arrangement (13) on the stirring head (3), which is in a drive ring (15) of the stirring head (3) surrounding the drive section (9). is arranged, wherein the stirring head (3) forms a radial plain bearing pairing with the bearing pin (7), a first axial magnet arrangement (17) arranged in the stirring head (3) being connected to a second axial magnet arrangement (19) arranged on the containment shell (5). forms an axially acting magnetic bearing pairing.

Description

TECHNICAL FIELD

The present disclosure relates generally and particularly to a magnetic stirrer with a stirring head, a containment can and a bearing pin according to claim 1.

TECHNICAL BACKGROUND

Magnetic stirrers are already used in process technology, especially in sterile technology. They are suitable for mixing liquid volumes from 2 liters to 50 m ³ in a hermetically sealed process room or process container. Such process containers are usually designed as standing cylindrical containers in which the magnetic stirrer is arranged somewhat eccentrically in the curved base and thus achieves complete mixing of the stirring medium due to the asymmetrical mixing effect.

In such magnetic agitators, a stirring head usually sits on a containment shell, with the stirring head forming a common plain bearing pairing with a bearing pin on the containment shell. There is a rotatable magnet in the containment shell, which drives the stirring head via rotation, with a magnet also being arranged in the stirring head. To minimize friction, bearing bushes can often be attached to the stirring head and in the area of the bearing journal. These can be specially sealed to close possible cavities or joints against external influences. One problem is that during operation, product residues, cleaning agents or water vapor can get into cavities or joints despite seals. This can be caused, for example, by temperature fluctuations, properties of the material to be stirred (creeping oils, etc.) or cleaning processes. These contaminants can often only be removed by completely dismantling the storage. To do this, it may be necessary to either remove and dismantle the containment shell or - in the case of a welded containment shell - to enter the container. If the joints/cavities are left uncleaned, the residues present there may become contaminated with germs and contaminate the mix. Such contamination is not acceptable in the largely aseptic or sterile production of pharmaceutical products or food.

Another problem is wear, which can occur particularly at contact points such as bearing bushes or axial stops. The bearing bushes can wear over time, causing material to be removed. The axial stop of the stirring head on the containment shell is particularly affected. Due to the structurally necessary stop, splinters can occur in this area, which can get into the mix. The DE 10 2013 104 788 A1 tries to solve this problem by using a bearing layer with increased hardness in the area of the bearing journal and a foot area surrounding the bearing journal. Furthermore, the magnets are arranged in such a way that the stirring head moves in such a way that it is slightly lifted by a buoyancy effect. When the stirring head stops, the buoyancy effect decreases and the stirring head settles again on the axial stop or the bearing layer, where it is then slidably mounted again.

It is often unavoidable to use the axial stop, especially with magnetic stirrers with a larger stirring head. This can significantly increase the risk of abrasion or splintering in the area of the axial stop, which is generally unacceptable in sterile technology, particularly in the production of pharmaceutical products or food.

From the WO 2011/049492 A1 A stirring device is known in which - partially exposed - magnets are arranged in the area of the bearing journal and the pair of plain bearings. This can, among other things, require a lot of manufacturing effort. When installed in this way, the magnets are only partially accessible or replaceable.

TASK

The object of the present invention is therefore to provide an improved magnetic stirrer in which the above-mentioned disadvantages are at least partially reduced.

SUMMARY

The present invention solves this problem. According to a first aspect, the present invention provides a magnetic agitator with a stirring head, a containment can and a bearing pin, the bearing pin being designed as a radial bearing section on the containment can, the containment can having a drive section in which a rotatable first magnet arrangement is arranged, which is magnetically connected a second magnet arrangement is coupled to the stirring head, which is arranged in a drive ring of the stirring head surrounding the drive section, the stirring head forming a radial plain bearing pairing with the bearing pin, wherein a first axial magnet arrangement arranged in the stirring head has a second axial magnet arrangement arranged on the containment shell axially acting magnetic bearing pairing forms. The axially acting magnetic bearing pairing can reduce or minimize the use of an axial stop. Furthermore, the axially acting magnetic Bearing pairing is easy to assemble and can be replaced with little effort if necessary.

The bearing pin can be connected to a plateau area of the containment shell via an end face or foot area of the bearing pin. The bearing pin and the containment can can be made in one piece or in two parts. The magnetic stirrer can be driven, for example, by a geared motor or another motor. The geared motor can in particular be a worm geared motor.

The first and second axial magnet arrangements are arranged outside the radial plain bearing pairing. Due to the arrangement of the axially acting magnetic bearing pairing, the radial mounting of the stirring head can be carried out partially magnetically via the first and second magnet arrangement and partially tribologically via the radial plain bearing pairing. One advantage that can result from this is that the radial plain bearing pairing, particularly in the area of the bearing journal, is not influenced by additional magnets or magnetic forces. This means that friction between the stirring head and the bearing pin can be further minimized. Furthermore, the formation of abrasion in the area of the bearing journal can be reduced. Because the axially acting magnetic bearing pairing does not influence the radial bearing, the overall friction can be reduced. As a result, the necessary drive energy can also be reduced.

The magnetic agitator or its individual components such as the stirring head, containment shell or bearing pin can be made of steel. The steel can be an austenitic steel material (e.g. 1.4301, 1.4404, 1.4435, 1.4462). The magnets, in particular the magnets of the first and/or second magnet arrangement, can be permanent magnets. The permanent magnet can be a neodymium-iron-boron, samarium-cobalt, alnico, sr-ferrite magnet or another permanent magnet. For sterilization, components of the magnetic stirrer are autoclaved at temperatures of up to 140 °C. Conventional magnets can lose a preset holding force in such a temperature range. Therefore, high-temperature magnets with a service temperature of at least 140 °C (e.g. type SH, UH, EH, AH, Y) can be used.

A polarity of the first and second axial magnet arrangements can be aligned or arranged in opposite directions. The first and second axial magnet assemblies can repel each other. The opposite polarity allows an axial magnetic force to be generated. The axial magnetic force between the first and second axial magnet arrangements can be adjustable via magnets. In a non-rotating state, the axial magnetic force can be greater than a weight force of the stirring head. The axial magnetic force can lift the stirring head in a non-rotating state relative to the containment shell in an axial direction. In a non-rotating state, the magnetic force can be less than the weight of the stirring head. The axial magnetic force can lift the stirring head in a rotating state in an axial direction, for example by a buoyancy effect/force.

BRIEF DESCRIPTION OF THE DRAWING

• 1 eine Halbschnittdarstellung eines erfindungsgemäßen Magnetrührwerks 1;
• 1a eine Halbschnittdarstellung des erfindungsgemäßen Magnetrührwerks 1 mit einer Lagerhülse;
• 1b eine Halbschnittdarstellung des erfindungsgemäßen Magnetrührwerks 1 mit einer erhöhten ersten Magnetanordnung 11;
• Fig, 1c eine Halbschnittdarstellung des erfindungsgemäßen Magnetrührwerks 1 mit einem Ausführungsbeispiel einer Lagerhülse 25 am Rührkopf 3;
• 2 eine Halbschnittdarstellung des erfindungsgemäßen Magnetrührwerks 1 mit einem zweiten Ausführungsbeispiel einer Axial-Magnetanordnung 17, 19;
• 3 eine Halbschnittdarstellung des erfindungsgemäßen Magnetrührwerks 1 mit einem dritten Ausführungsbeispiel einer Axial-Magnetanordnung 17, 19; und
• 4 eine schematische Darstellung der ersten und zweiten Axialmagnetanordnung 17, 19.

Embodiments are described by way of example and with reference to the accompanying drawings. Show it:

• 1 a half-sectional view of a magnetic stirrer 1 according to the invention;
• 1a a half-sectional view of the magnetic agitator 1 according to the invention with a bearing sleeve;
• 1b a half-sectional view of the magnetic stirrer 1 according to the invention with a raised first magnet arrangement 11;
• 1c shows a half-sectional view of the magnetic stirrer 1 according to the invention with an exemplary embodiment of a bearing sleeve 25 on the stirring head 3;
• 2 a half-sectional view of the magnetic stirrer 1 according to the invention with a second exemplary embodiment of an axial magnet arrangement 17, 19;
• 3 a half-sectional view of the magnetic stirrer 1 according to the invention with a third exemplary embodiment of an axial magnet arrangement 17, 19; and
• 4 a schematic representation of the first and second axial magnet arrangements 17, 19.

DESCRIPTION OF EMBODIMENTS

Before a detailed description of the embodiment with reference to 1 General explanations of the embodiments follow first.

The term “axial” in claim 1, among others, refers to an axis of rotation about which the stirring head is rotatably mounted. The axis of rotation passes axially through a cylindrical bearing journal.

The term “higher” in claim 2, among others, refers to a height difference along the axis of rotation. In this context, “higher” is the direction that runs in the direction of an end face of the journal.

• Es gibt Ausführungsformen, bei denen die erste Axial-Magnetanordnung und/oder die zweite Axial-Magnetanordnung um die Rotationsachse radial beabstandet ist und konzentrisch zur Rotationsachse ausgerichtet ist. Die erste Axial-Magnetanordnung und/oder die zweite Axial-Magnetanordnung kann derart angeordnet sein, dass sie die Rotationsachse nicht kontaktieren. Die erste Axial-Magnetanordnung und/oder die zweite Axial-Magnetanordnung kann als Ringmagnet ausgeführt sein.

The magnetic stirrer according to the invention is characterized by the following:

• There are embodiments in which the first axial magnet arrangement and/or the second axial magnet arrangement is radially spaced around the axis of rotation and is aligned concentrically to the axis of rotation. The first axial magnet arrangement and/or the second axial magnet arrangement can be arranged such that they do not contact the axis of rotation. The first axial magnet arrangement and/or the second axial magnet arrangement can be designed as a ring magnet.

There are embodiments in which the first magnet arrangement is arranged higher along an axis of rotation than the second magnet arrangement. The first magnet arrangement can be arranged higher than the second magnet arrangement in a non-rotating state. The first magnet assembly may be arranged higher than the second magnet assembly in a non-rotating state and a state in which the axial magnet assembly does not lift the stirring head. Advantageously, the first magnet arrangement can be arranged between 1 mm and 4 mm higher, in particular between 1 mm and 3 mm, in particular 2 mm. Due to the higher first magnet arrangement in the containment shell, the stirring head can be easily raised when rotating. This can reduce friction in the axial stop, especially when starting up and switching off the magnetic stirrer.

There are embodiments in which the stirring head has a first radially circumferential groove, with the first axial magnet arrangement being arranged in the first circumferential groove. The radially circumferential groove can be arranged in the stirring head, in particular in a bearing ring. The bearing ring can be arranged in the area of the bearing journal. A bearing sleeve can be formed inside the bearing ring. The bearing sleeve can be firmly connected to the bearing ring. The bearing sleeve can rotate together with the stirring head. The bearing sleeve on the bearing ring can be made of a ceramic material. The ceramic material can be silicon carbide (SiC).

The groove can have a square cross section. The groove can be square or rectangular. The first axial magnet arrangement can be in one piece or in several parts. The axial magnet arrangement can be ring-shaped. The multi-part axial magnet arrangement can include several magnet segments. A magnet segment can be square or in the shape of a circular ring segment. The first axial magnet arrangement can be partially or completely embedded in the groove. The first axial magnet arrangement can form a flush end with the groove and/or an inner lateral surface of the stirring head.

There are embodiments in which the first axial magnet arrangement is enclosed in a media-tight manner on all sides. The magnet arrangement can be enclosed in a media-tight manner on all sides, particularly in a case in which the magnet arrangement is to be encapsulated against fluids, in particular liquids. Due to the complete encapsulation, no residue or deposits can form in the area of the first axial magnet arrangement. This is particularly advantageous for a sterile work environment. The first axial magnet arrangement can be completely positively enclosed in the stirring head, in particular the bearing ring. The first axial magnet arrangement can be enclosed using a laser welding process with or without foreign material.

There are embodiments in which the second axial magnet arrangement is arranged on the containment shell between the first magnet arrangement in the drive section and the bearing journal. The second axial magnet arrangement is arranged below or lower than the first axial magnet arrangement when viewed from the axis of rotation. The second axial magnet arrangement on the containment shell can be arranged on an inside of the containment shell, on an outside of the containment shell or within a wall of the containment shell. Because the second axial magnet arrangement is not arranged on the bearing journal, the formation of a structural joint or a cavity in the area of the bearing journal can be avoided. Because the second axial magnet arrangement is not arranged on the bearing journal, the area of the bearing journal can be designed without joints, grooves or other recesses. This can minimize wear and/or abrasion in the area of the plain bearing pairing.

There are embodiments in which the second axial magnet arrangement is enclosed in a media-tight manner on all sides. What was said about the first axial magnet arrangement regarding the arrangement that is enclosed in a media-tight manner on all sides can be applied analogously to the second axial magnet arrangement.

There are embodiments in which a second radially circumferential groove is formed on the containment shell, with the second axial magnet arrangement being arranged in the second radially circumferential groove. The groove can be formed on the inside of the containment shell or on the outside of the containment shell. The groove in the containment shell can have a square cross section. The groove can be square or rectangular. The second axial magnet arrangement can be in one piece or in several parts. The axial magnet arrangement can be ring-shaped. The multi-part axial magnet arrangement can include several magnet segments. One magnet segment can accommodate four be angular or circular ring segment shaped. The second axial magnet arrangement can be completely embedded in the groove. The second axial magnet arrangement can form a flush end with the groove.

There are embodiments in which the second circumferential groove is arranged on an inside of the containment shell facing the rotatable first magnet arrangement or on an outside of the containment shell facing the stirring head. The outside of the containment can can be a plateau area of the containment can. In the case in which the second axial magnet arrangement is arranged on the inside of the containment shell, the second axial magnet arrangement can be enclosed in a media-tight manner on all sides by the structural arrangement of the containment shell. At the same time, the second axial magnet arrangement can only be accessible via the inside of the containment shell. In the case in which the second axial magnet arrangement is arranged on the outside of the containment shell, the second axial magnet arrangement can be accessible without dismantling the drive section. This is advantageous, for example, during replacement or maintenance.

There are embodiments in which the bearing journal includes a bearing sleeve in the section of the plain bearing pair. The bearing sleeve can improve the tribological properties in the area of the bearing journal or plain bearing pairing. This can minimize wear and abrasion.

The bearing sleeve can be cylindrical or tubular. A shoulder (collar) can be formed on one end face of the bearing sleeve. The shoulder can be disc-shaped. The shoulder can rest on the plateau area of the containment shell. The bearing sleeve can be plugged onto the bearing journal, shrunk on or pressed on. The bearing sleeve can be guided axially by the bearing journal. The bearing sleeve can be secured against rotation with an anti-twist device. The bearing sleeve can be made of bronze, white metal, plastic, ceramic, a brass alloy or another advantageous material.

The bearing sleeve can be a coating. The coating can be cohesively connected to the bearing journal and/or the upper section of the containment shell. The coating can have a thickness between 2 µm and 2 mm, in particular between 2 µm and 30 µm.

There are embodiments in which the second axial magnet arrangement is arranged between the bearing sleeve and the containment shell. When arranged between the bearing sleeve and the containment shell, the second axial magnet arrangement can be arranged in the area of the containment shell without having to make a geometry adjustment in the area of the containment shell or the bearing journal. The second axial magnet arrangement can be arranged in the bearing sleeve. In the case in which the second axial magnet arrangement is arranged in the bearing sleeve, accessibility of the second axial magnet arrangement from the outside may be possible. This allows installation and maintenance to be improved/simplified.

The second axial magnet arrangement can be arranged in the shoulder area of the bearing sleeve. An additional radially circumferential groove can be formed in a heel area of the bearing sleeve. The groove can be a recess. The heel area can be a transition or connection area between the tubular section and the shoulder. The second axial magnet arrangement can be flush with a standing area of the bearing sleeve or shoulder in a standing area of the bearing sleeve. The standing surface can face the containment can.

There are embodiments in which the second axial magnet arrangement is enclosed on all sides by the bearing sleeve and the containment shell. The bearing sleeve can include an additional seal. The seal can be arranged in the lower area of the bearing sleeve or the shoulder. The seal can be an O-ring. The seal can additionally seal a joint or a cavity formed by the bearing sleeve against dirt or residue.

For simplicity, all representations are in 1 until 4 the magnetic stirrer 1 is only half shown.

Coming back to 1 This shows the structure of a magnetic stirrer 1 according to the invention in half section. The magnetic agitator 1 includes a stirring head 3 and a containment pot 5. The magnetic agitator 1 is inserted into a process container (not shown). Inside a hollow drive section 9, which is pot-shaped, there is a rotatable first magnet arrangement 11, which is connected to a drive motor (not shown) via a drive shaft 6.

The stirring head 3 includes a bearing ring 8, a drive ring 15 and several wing elements 4, which each connect the drive ring 15 to the bearing ring 8. The bearing ring 8 and the drive ring 15 are arranged concentrically to a rotation axis R. A second magnet arrangement 13 is arranged inside the drive ring 15 and is magnetically coupled to the rotatable first magnet arrangement 11. Between the inside of the Drive ring 15 and the outside of the containment pot 5 is a gap.

Inside the bearing ring 8, a cylindrical bearing sleeve 25 is arranged, which sits slidably on a bearing pin 7, which is formed in one piece on a plateau area 5b of the containment shell 5. The cylindrical bearing sleeve 25 is firmly connected to the bearing ring 21. A diameter of the plateau area 5b is larger than a diameter of the bearing pin 7. The plateau area 5b around the bearing pin 7 is annular disk-shaped and forms a flat surface.

A first axial magnet arrangement 17 is arranged inside the bearing ring 8. The first axial magnet arrangement 17 is aligned above the plateau area 5b and within the annular disk-shaped section at a distance from the plateau area 5b. The first axial magnet arrangement 17 is embedded in the bearing ring 8 in a first radially circumferential groove 21. The first axial magnet arrangement 17 is surrounded by three side surfaces of the bearing ring 8. The first axial magnet arrangement 17 is surrounded on all sides by an outer surface of the bearing sleeve 25 and the first radially circumferential groove 21.

On the inside 5a of the containment shell 5, a second axial magnet arrangement 19 is arranged in the section of the plateau area 5b within the annular disk-shaped section. The second axial magnet arrangement 19 is embedded in a second radially circumferential groove 23 on the inside 5a. A thickness of the second axial magnet arrangement 19 is less than a wall thickness of the containment shell 5. The second axial magnet arrangement 19 is arranged to be accessible from the inside 5a of the containment shell 5.

The stirring head 3 is raised relative to the plateau region 5b of the containment shell 5 by a repelling magnetic force F _A generated by the first and second axial magnet arrangements 17, 19.

According to the present invention shows 1a the magnetic stirrer 1 according to the invention. In contrast to 1 an additional bearing sleeve 27 is arranged on the bearing pin 7 on the magnetic stirrer 1. The bearing sleeve 27 is arranged concentrically and non-rotatably around the bearing journal 7 in the area of the bearing journal 7. An inner lateral surface of the bearing sleeve 27 contacts a lateral surface of the bearing pin 7. An outer lateral surface of the bearing sleeve 27 contacts an inner lateral surface of the bearing sleeve 25 on the bearing ring 8.

The cylindrical bearing sleeve 27 has an annular disk-shaped collar region 27a formed on one end face. The federal area 27a sits on the plateau area 5b. The collar area 5b is sandwiched between the bearing ring 8 and the plateau area 5b.

According to the present invention shows 1b the magnetic agitator 1 according to the invention with an elevated first magnet arrangement 11. When viewed relative to the vertical axis of rotation R, the first magnet arrangement 11 in the containment shell 5 is arranged in the non-rotating state at a distance s higher than the second magnet arrangement 13 in the drive ring 15. In 1b the magnetic force F _A of the first and second axial magnet arrangements 17, 19 is less than a weight of the stirring head 3. A lower end face of the bearing ring 8 contacts the plateau area 5b of the containment shell 5 in the non-rotating state.

According to the present invention shows 1c a half-sectional view of the magnetic agitator 1 according to the invention with an exemplary embodiment of the bearing sleeve 25 on the stirring head 3. A shoulder-like collar region 25a is formed on the bearing sleeve 25 in a section facing the containment shell 5. The second axial magnet arrangement 17 is contacted by the bearing sleeve 25 on two sides. The bearing sleeve 25 and the bearing ring 8 enclose the second axial magnet arrangement 17 together on all sides. According to the present invention shows 2 a half-sectional view of the magnetic stirrer 1 according to the invention with a second exemplary embodiment of an axial magnet arrangement 17, 19. In contrast to the first exemplary embodiment in 1 and 1a is in 2 the second axial magnet arrangement 19 is arranged on the annular section of the plateau area 5b. The exposed second axial magnet arrangement 19 is covered by the bearing sleeve 27 with the collar area 27a. In the waistband area 27a, a radially circumferential recess 27b is formed in a heel area on the end face facing the plateau area 5b. The first axial magnet arrangement 17 is inserted into the recess 27b. An underside of the first axial magnet arrangement 17 forms a common plane with a base area of the collar region 27a.

According to the present invention shows 3 the magnetic agitator 1 according to the invention with a third exemplary embodiment of an axial magnet arrangement 17, 19. A connecting base 29 is formed in a lower section of the containment shell. The magnetic agitator 1 is connected to a housing of the drive motor (not shown) via the connecting base 29. A flange-like shoulder 29a is formed on the connecting base 29 below the drive ring 15 of the stirring head 3. The flange-like shoulder 29a forms an axial stop of the drive ring 15. In the The second axial magnet arrangement 19 is arranged in a flange-like shoulder 29a. The first axial magnet arrangement 17 is arranged in an end face of the drive ring 15 facing the flange-like shoulder 29a. The stirring head 3 is raised in the axial direction via the magnetic force F _A of the first and second axial magnet arrangements 17, 19.

According to the present invention shows 4 two schematic representations of the first and second axial magnet arrangements 17, 19. The first and second axial magnet arrangements 17, 19 are arranged spaced one above the other along the axis of rotation R. The first and second axial magnet arrangements 17, 19 each have a magnetic dipole. A polarity of the first and second axial magnet arrangements 17, 19 is each aligned orthogonally to the axis of rotation R and divides the first and second axial magnet arrangements 17, 19 into a south pole S and a north pole N. The polarity of the first and second axial magnet arrangements 17, 19 is arranged opposite. In the left schematic representation, the north poles N1 and N2 repel each other. In the right schematic representation, the south poles S1 and S2 repel each other.

Further embodiments and variants of the invention will become apparent to those skilled in the art within the scope of the claims.

REFERENCE SYMBOL LIST

1

Magnetic stirrer

3

Stirring head

4

Wing elements

5

containment pot

5a

Inside of the containment shell

5b

Plateau area

6

drive shaft

7

bearing journal

8th

Bearing ring

9

Drive section

11

First magnet arrangement

13

Second magnet arrangement

15

Drive ring

17

First axial magnet arrangement

19

Second axial magnet arrangement

21

First radially circumferential groove

23

Second radially circumferential groove

25

Bearing sleeve on the stirring head

27

Bearing sleeve on bearing journal

27a

Federal area

27b

recess

29

Connection base

29a

Flange-like heel

R

Axis of rotation

FA

Axial magnetic force

s

Distance

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013104788 A1 [0004]
• WO 2011049492 A1 [0006]

Claims (12)

Magnetic agitator (1) with a stirring head (3), a containment shell (5) and a bearing pin (7), the bearing pin (7) being designed as a radial bearing section on the containment shell (5), the containment shell (5) having a drive section (9 ), in which a rotatable first magnet arrangement (11) is arranged, which is magnetically coupled to a second magnet arrangement (13) on the stirring head (3), which is in a drive ring (15) of the stirring head (3) surrounding the drive section (9). is arranged, wherein the stirring head (3) forms a radial plain bearing pairing with the bearing pin (7), a first axial magnet arrangement (17) arranged in the stirring head (3) being connected to a second axial magnet arrangement (19) arranged on the containment shell (5). forms an axially acting magnetic bearing pairing. Magnetic stirrer (1). Claim 1 , wherein the first axial magnet arrangement (17) and / or the second axial magnet arrangement (19) is radially spaced about an axis of rotation (R) and is aligned concentrically to the axis of rotation (R). Magnetic agitator (1) according to one of the preceding claims, wherein the first magnet arrangement (11) is arranged higher along an axis of rotation (R) than the second magnet arrangement (13). Magnetic agitator (1) according to one of the preceding claims, wherein the stirring head (3) has a first radially circumferential groove (21), the first axial magnet arrangement (17) being arranged in the first radially circumferential groove (21). Magnetic stirrer (1) according to one of the preceding claims, wherein the first axial magnet arrangement (17) is enclosed in a media-tight manner on all sides. Magnetic agitator (1) according to one of the preceding claims, wherein the second axial magnet arrangement (19) is arranged on the containment shell (5) between the first magnet arrangement (11) in the drive section (9) and the bearing pin (7). Magnetic agitator (1) according to one of the preceding claims, wherein the second axial magnet arrangement (19) is enclosed in a media-tight manner on all sides. Magnetic agitator (1) according to one of the preceding claims, wherein a second radially circumferential groove (23) is formed on the containment pot (5), the second axial magnet arrangement (19) being arranged in the second radially circumferential groove (23). Magnetic agitator (1) according to one of the preceding claims, wherein the second radially circumferential groove (23) on an inside (5a) of the containment shell (5) facing the rotatable first magnet arrangement (11) or on an outside of the containment shell facing the agitator (3). (5) is arranged. Magnetic agitator (1) according to one of the preceding claims, wherein the bearing pin (7) comprises a bearing sleeve (27) in the section of the plain bearing pairing. Magnetic stirrer (1). Claim 10 , wherein the second axial magnet arrangement (19) is arranged between the bearing sleeve (27) and the containment shell (5). Magnetic stirrer (1). Claim 10 or 11 , wherein the second axial magnet arrangement (19) is enclosed on all sides by the bearing sleeve (27) and the containment can (5).

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