EP1188474B1 - Magnetic stirrer - Google Patents

Description

The invention relates to a magnetic stirring device according to the preamble of claim 1. The invention further relates to a stirring device according to the The preamble of claim 10.

Bar magnets are known which are used for stirring liquids be used by the bar magnet containing a liquid Container is attached, and the container to a rotating magnetic field is set so that the bar magnet is set in rotation.

A disadvantage of such bar magnets is the fact that these on the Bottom of the container rest and thereby only a limited Create stirring effect. The between the bar magnet and the ground occurring friction forces can also cause abrasion or in the liquid contained parts such as living cells destroy.

From document JP 6-261747 is a floating magnetic stirring device known and document US 4,465,377) discloses a magnetic stirring device with combined stirring / floating part, which on the surface of the liquid floats.

It is an object of the present invention a more advantageous Magnetic stirring device or propose a more advantageous mixer.

This object is achieved with a Magnetirührvorrichtung having the Features of claim 1. The dependent claims 2 to 7 relate to further, Advantageously designed magnetic stirring devices. The task will continue solved with a stirrer having the features of claim 8. The Subclaims 9 to 12 relate to further, advantageously designed Stirrers.

The object is achieved in particular with a magnetic stirring device comprising a stirring member, a permanent magnet and a Floats, which are connected to each other.

An essential aspect of the invention is the Magnetic stirring device to design such that the stirring member with respect spaced from the bottom of the container, so that the stirring member no longer sliding on the ground while stirring.

In a preferred embodiment, the magnetic stirring device is elongate, designed substantially rod-shaped, wherein in the region of the first Endabschnittes the stirring part and in the region of the second end portion Floating body is arranged. In a particularly advantageous Embodiment is the end of the first end portion as a tip designed. This magnetic stirring device becomes a liquid container containing the magnetic stirring device through the on the float acting buoyancy forces in a substantially is held vertically extending and against tilting is stabilized. The float thus causes a hydrodynamic Stabilization of the magnetic stirrer against tilting, and stabilized thus the magnetic stirring device with respect to two degrees of freedom.

Below the bottom of the container, a device is arranged, which to generate a magnetic rotating field. In a preferred Embodiment is comprising this device as a magnetic coupling designed a rotating permanent magnet. This Permanent magnet acts on the arranged in the stirring part Permanent magnets. By thus formed magnetic coupling is the Location of the stirring and thus the position of the Magneticührvorrichtung respect determined three degrees of freedom, namely in the x and y direction and with respect the rotation. In the vertical direction or in the direction of the Magnetic stirring device, this is through the tip, which together with the Bottom of the tank is forming a top bearing, only with respect to one Stabilized movement downwards. Together with the down-acting Magnetic force of the magnetic coupling is also the vertical degree of freedom (z-direction) stabilized.

The magnetic stirring device is thus stabilized with respect to 6 degrees of freedom. The aforementioned, known bar magnet is only with respect to 4 Degrees of freedom stabilized, namely in x- and y-direction, with respect to rotation, and, as it lies on the bottom of the container, with respect to a movement downward. The magnetic stirring device according to the invention thus has the Advantage that it is stabilized in terms of more degrees of freedom, what it allows the stirring member to be spaced from the bottom of the container.

In a further advantageous embodiment, the magnetic stirring device is in the liquid of the container is arranged floating, wherein the Magnetic stirring device via an outside of the container arranged Magnetic field is drivable. The required for driving rotating Magnetic field can be generated by means of electromagnetic coils or with rotatably mounted magnet, in particular with rotatably mounted Permanent magnets, which with the Magnetirührvorrichtung a Form magnetic coupling. In an advantageous embodiment is under Use of the permanent magnets of the magnetic stirrer also the Location of the magnetic stirrer influenced by these permanent magnets Form part of a passive magnetic bearing. The one part of the passive Magnetic bearing is located outside the container and exercises a stabilizing effect on the location of itself within the container located Magnetirührvorrichtung off.

The object is further achieved with a stirrer comprising a Magnetic stirring device with one or more permanent magnets and a floating body, as well as comprising a magnetic Drive device, wherein the drive device and the Permanent magnets of the magnetic stirring so mutually adapted are arranged and configured to form a magnetic coupling.

Fig. 1

einen Längsschnitt durch ein Rührgerät mit im Behälter aufliegender Magnetrührvorrichtung.

Fig. 1a

eine Detailansicht des Rührteils;

Fig. 1b

eine Magnetrührvorrichtung mit vollständig untergetauchtem Schwimmkörper;

Fig. 2

einen Längsschnitt durch ein erstes Rührgerät mit einer Magnetrührvorrichtung;

Fig. 3

ein Weg-Kraft-Diagramm der Magnetrührvorrichtung;

Fig. 4

einen Querschnitt durch einen Schwimmkörper;

Fig. 5

ein Weg-Kraft-Diagramm einer weiteren Magnetrührvorrichtung;

Fig. 6

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 7

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 8a-8f

unterschiedliche Anordnungen der Permanentmagnete von Magnetrührvorrichtung und Rührgerät;

Fig. 9

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 10

eine Aufsicht auf die in Fig. 10 dargestellte Antriebsvorrichtung;

Fig. 11

einen Längsschnitt durch ein mit elektromagnetischen Spulen versehenes Rührgerät mit einer Magnetrührvorrichtung;

Fig. 12

eine Aufsicht auf die in Fig. 11 dargestellten elektromagnetischen Spulen;

Fig. 13

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 14

einen Querschnitt durch einen an der Magnetrührvorrichtung angeordneten Flügel;

Fig. 15

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 16

einen Querschnitt durch den Behälter gemäss Fig. 15 entlang der Schnittlinie A-A;

Fig. 17

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 18

einen Querschnitt durch das in Fig. 17 dargestellte Rührgerät entlang der Schnittlinie D-D;

Fig. 19

einen Längsschnitt durch ein weiteres Rührgerät mit Magnetrührvorrichtung;

Fig. 20

einen Querschnitt durch das in Fig. 19 dargestellte Rührgerät entlang der Schnittlinie E-E;

Fig. 21

ein Rührgerät in Kombination mit einem Bioreaktor.

The invention will be described below with reference to several embodiments. Show it:

Fig. 1

a longitudinal section through a stirrer with resting in the container Magnetirührvorrichtung.

Fig. 1a

a detailed view of the stirring member;

Fig. 1b

a magnetic stirrer with completely submerged float;

Fig. 2

a longitudinal section through a first mixer with a Magnetetrührvorrichtung;

Fig. 3

a path-force diagram of the magnetic stirring device;

Fig. 4

a cross section through a float;

Fig. 5

a path-force diagram of another magnetic stirring device;

Fig. 6

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 7

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 8a-8f

different arrangements of the permanent magnets of magnetic stirring device and mixer;

Fig. 9

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 10

a plan view of the drive device shown in Figure 10;

Fig. 11

a longitudinal section through a provided with electromagnetic coils stirring device with a magnetic stirring device;

Fig. 12

a plan view of the electromagnetic coils shown in Figure 11;

Fig. 13

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 14

a cross section through a arranged on the magnetic stirrer wings;

Fig. 15

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 16

a cross section through the container according to FIG 15 along the section line AA.

Fig. 17

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 18

a cross section through the agitator shown in Figure 17 along the section line DD.

Fig. 19

a longitudinal section through another stirring device with Magnetetrührvorrichtung;

Fig. 20

a cross section through the agitator shown in Figure 19 along the section line EE.

Fig. 21

a stirrer in combination with a bioreactor.

1 shows a longitudinal section of a magnetic stirring device 1 comprising a stirring member 1a, a rod 1b and a floating body 1f, which connected to each other. Within the stirring part 1a, as in Fig. 1a shown in section F-F, two permanent magnets 1d, 1e with respect to Bar 1b arranged symmetrically. The bar 1b opens down into a peak 1c, which together with the bottom of the container 3, a top bearing formed. In the first end portion 1o of the rod 1b, the stirring part 1a is light spaced apart from the tip 1c, so that the agitating part covers the bottom of the Container 3 not touched. In the second end portion 1p is the float 1f arranged. The floating body 1f is in the running direction of the bar 1b displaceable and can with a fastener, not shown, such as a screw are firmly connected to the rod 1b. The Magnetic stirring device 1 is characterized by which within the container. 3 located liquid 4 and thereby caused on the float 1 f Buoyancy FAZ held in a substantially vertical position. Of the Float 1f thus stabilizes the magnetic stirring device 1 Hydrostatic against tilting, so the location of the Magnetic stirring device thereby with respect to two degrees of freedom hydrostatically stabilized.

Below the container 3, a drive device 2 is arranged. The Drive device 2 comprises a plate 2a and in the direction of rotation 2e rotatably mounted axis 2b, wherein two permanent magnets 2c, 2d with the Plate 2a are firmly connected. The permanent magnets 1d, 1e of Magnetic stirring device 1 and the permanent magnets 2c, 2d of Drive device 2 are arranged mutually adapted and designed to mutually form a magnetic coupling to the Magnetic stirring device 1 to drive in the direction of rotation 2e. These Magnetic coupling stabilizes the magnetic stirring device 1 with respect to Radial position in the x and y direction and in the direction of rotation, so that the Magnetic coupling, the magnetic stirring device 1 with respect to three degrees of freedom stabilized.

The magnetic stirring device 1 is on the top bearing 1 c, so that the Magnetic stirring device 1 stabilized with respect to a downward movement is, so that the magnetic stirring device 1 with respect to a degree of freedom the top bearing and the magnetic attraction between the Permanent magnets 1d, 1e, 2c, 2d is stabilized. Thus, the location of the Magnetic stirring device 1 by the means shown in Fig. 1 with respect to 6 Degrees of freedom stabilized.

A necessary condition of hydrostatic stabilization is that of Float 1f is at least partially immersed in the liquid, or as shown in Fig. 1b, completely submerged. So that Top bearing 1c rests on the bottom of the container 3, it is necessary that the weight of the magnetic stirring device 1 as well as by the Magnetic coupling caused attraction is greater than that by the Float caused buoyancy FAZ.

In contrast to the arrangement shown in Fig. 1, the in Fig. 2 shown Magneticührvorrichtung 1 in the liquid 4 of the container. 3 kept floating, since the buoyancy FAZ, as well as the weight the magnetic stirring device 1 and caused by the magnetic coupling magnetic force are in an equilibrium position. This is the Float 1f in the corresponding position along the bar 1b to arrange. To meet this condition, the float 1f is on the rod 1b slidably, so that the position of the floating body 1f Depending on the fluid level is adjustable so that the Magnetic stirring device 1 with the tip 1 c on the bottom of the container. 3 stands. After moving the float 1f this is For example, with a screw firmly connected to the rod 1b.

This arrangement has the advantage that the magnetic stirring device 1 floating and non-contact in the container 3 is held.

The distance between the stirring part 1a and the bottom of the container 3 is represented by the dimension z. Against the bottom acts on the Magnetic stirring device 1 a force FMZ, which is derived from gravity and caused by the drive device 2 magnetic Attraction is composed.

Fig. 3 shows the path-force diagram of floating in the liquid Magnetic stirring device 1, wherein in the abscissa the sinking depth z and in the Ordinate the force F is shown. Which by itself in a liquid like Float 1f caused buoyancy FAZ takes with increasing sinking depth in function of the height h linear to, and decreases after complete immersion of the float 1f a constant value. In addition, the force curve of the force FMZ in function of Dimension z shown. At the intersection G of the two curves FMZ and FAZ sets a stable equilibrium position. In Fig. 3, the difference of Force FMZ and the force FAZ shown as a dashed curve. Between two saddle points, limited by the height of the float, returns the system returns to the stable equilibrium position G after a fault back. The maximum amount of difference between FAZ and FMZ is thus a measure of the robustness of the system. With this measure, the last degree of freedom of the magnetic stirring device 1, namely the movement vertically upwards, through the buoyancy force along with the stabilized opposite magnetic force, so that 3 ½ Degrees of freedom of the magnetic stirring 1 are magnetically stabilized, and 2½ degrees of freedom of the magnetic stirrer 1 hydrostatically stabilized are.

The buoyancy of the float 1f in function of the sinking is of course determined by the shape of the float 1f. Fig. 4 shows in a longitudinal section a floating body 1f, which along a Height h1 frusto-conical and along the height h2 cylindrical is trained.

5 shows the weaving force diagram of a magnetic stirring device 1 having the floating body 1f shown in Fig. 4. The force FMZ has the same, already shown in Fig. 3 course. The by the Float 1f generated buoyancy force FAZ points along the section h1 has a curved, in particular square, force increase, whereas the float 1f in the cylindrically shaped section h2 causes a linear force increase. When completely submerged Float 1f buoyancy takes a constant value. The stable one Point of equilibrium G turns again at the intersection of the two Curves FAZ and FMZ. Compared to that shown in Fig. 3 Curve shows the maximum difference between the forces FMZ and FAZ a higher (negative) amount. There, as with the description of Fig. 3 explains that this is a measure of the robustness of the system, this has in the Compared to Fig. 3 has the advantage that the magnetic stirring 1 more stable in the balance can be kept. When stirring the liquid results namely due to the centrifugal force acting the problem that the Liquid level in the middle of the container 3 drops, at the edge on the other hand rises. This has the consequence that the float 1 f in the container 3 decreases slightly, which in turn means that the distance z is reduced. Also in this position, the magnetic stirring device 1 should be contactless in Container 3 are kept floating. To be stable behavior too It is therefore of particular importance that the difference steady between the forces FMZ and FAZ over a longer section run.

In contrast to the stirring device 6 shown in Fig. 2 are in Embodiment according to FIG. 6, the permanent magnets 1e, 2c in polarized opposite direction arranged.

In contrast to the stirring device 6 shown in Fig. 2 are in Embodiment according to FIG. 7, the permanent magnets 1d, 1e in polarized horizontally, whereas the Permanent magnets 2c, 2d of the drive device 2 in the vertical direction and oppositely polarized.

The permanent magnets 1d, 1e of the stirring part 1a and the permanent magnets 2c, 2d of the drive device 2 could in different ways be arranged to mutually form a magnetic coupling. In the Figures 8a to 8f show several examples of such arrangements. In the plan shown in Fig. 8a on the plate 2a of Drive device 2, the four arranged distributed in the circumferential direction Permanent magnets 2c, 2d shown, wherein the permanent magnets 2c and 2d are oppositely polarized. Fig. 8b shows an arrangement with only two permanent magnets 2c, 2d. In Fig. 8c, the stirring part 1a has a single bar magnet 1d on. In Fig. 8d, the stirring member 1a is cross-shaped configured, wherein in each arm of the cross a permanent magnet 1d, 1e is arranged. In Fig. 8e, the stirring part 1a is configured star-shaped, wherein a permanent magnet 1d is arranged in each arm. On the plate 2a are also arranged three permanent magnets 2c. In Fig. 8f is the Stirring 1a as configured in Fig. 8d as a cross, wherein the polarization of the Permanent magnets, in contrast to the embodiment of FIG. 8d, different is aligned. Examples of further arrangements of Permanent magnets are, for example, in the article "Permanent Magnet Bearings and Couplings, J.P. Yonnet, IEEE Transactions on magnetics, Vol. Mag-17, No. 1, January 1981 ".

In contrast to the stirring device 6 shown in FIG. 2, the plate 2a the drive device 2 according to FIG. 9 has a relatively large diameter , wherein the permanent magnets 2c, 2d, as in the plan view of FIG. 10 shown, are formed circular segment. The stirring part 1a is as shown in Fig. 10, designed cross-shaped. An advantage of the in Fig. 9 The arrangement shown can be seen in that by the Drive device 2 caused magnetic field in the vertical direction only a small change, so that a change in position of Magnetic stirring device 1 in the vertical direction to the through Permanent magnets 2c, 2d, 1d, 1e formed magnetic coupling one only has little influence on the coupling behavior.

In contrast to the stirring device 6 shown in FIG. 2, in the stirring device 6 shown in FIG. 11 illustrated embodiment, the drive device 2 as a A plurality of bobbins 2f configured which, as shown in the in Fig. 12 shown section along the line D-D seen in the circumferential direction regularly spaced to order through a corresponding Control to generate an electromagnetic rotating field. These coils have several advantages. In contrast to permanent magnets whose Attraction force is the greater, the closer the agitating part is, can with the Coils a constant magnetic field are generated, so that the Attraction with smaller distance to the agitator no bigger becomes. In addition, the magnetic field strength over the current of the coils adjustable. This exerts a stabilizing influence on the situation of the Magnetic stirring device off.

In contrast to the mixer 6 shown in Fig. 2, the Magnetic stirring device 1 in the embodiment shown in Fig. 13 three vertically spaced wings or blades 1h, 1i, 1k on. This allows the rotational forces of the magnetic stirring device 1 better to transfer to the liquid 4. The illustrated in Fig. 14 Section along the line C-C shows the cross-shaped wing 1h on average. In addition, the arranged underneath, cruciform wing and the lowest arranged stirring part 1a shown.

In contrast to the stirring device 6 shown in FIG. 2, that shown in FIG. 15 shown magnetic stirring device 1 an additional wing 1h, which is firmly connected to the bar 1b. This wing 1h serves to the on the magnetic stirring device attacking rotational forces better on the Transfer liquid 4. The stirring of the liquid 4 causes the Liquid level 4a increases at the edge of the container 3, whereas the Liquid level 4a sinks in the middle, with the result that the Magnetic stirring device 1 drops. The change of the liquid level 4a or the rotational speed of the liquid can be reduced within the container 3 by on the inner wall of the Container 3, as shown in Fig. 16 along the section A-A, a A plurality of radially inwardly projecting rotary brakes 3a arranged become.

In contrast to the stirring device 6 shown in FIG. 2, that shown in FIG. 17 Magnetic stirring device 1 shown an annular configured Float 1f, which via a connecting means 1l with the rod 1b is connected. The arrangement and design of the floating body 1f is chosen such that it changes during stirring Liquid level 4a is not or only slightly on the level of Magnetic stirring 1 affects. By stirring the liquid 4 points this on the designated 4a surface course.

The magnetic stirring device 1 has a relatively high mass and is therefore possibly difficult in the radial direction by the drive device 2 to keep. Advantageously, therefore, the float 1f with a stabilized additional device. These are within the Float 1f 1m circumferentially extending permanent magnets arranged. In addition, outside the container 3 is an in Displacement direction 5f movable adjusting 5 arranged, which In the circumferential direction distributed permanent magnets 5a, 5b has. The permanent magnets 5a, 5b are so with respect to the permanent magnets 1m arranged that by a corresponding displacement of the Adjustment 5 in the vertical direction 5f also the vertical position of the Magnetic stirring device 1 is adjustable. It is therefore advantageous to use the radial Position of the float 1f with the through the permanent magnets 1m, 5a, 5b formed passive radial magnetic bearing in addition to stabilize.

The section along the line D-D shown in Fig. 18 shows the Container wall 3 and the outside of the container 3 arranged Adjustment device 5 with support means 5e, on which the permanent magnets 5a, 5b, 5c, 5d are arranged adjustable in the direction 5f. Within of the cavity of the floating body 1f are circumferentially extending a plurality of permanent magnets 1m arranged.

The agitator 6 shown in a longitudinal section in FIG. 19 has a Magnetic stirring device 1 '(not the subject of the present invention), which has an annular configured agitating part 1a, which solid is connected to a hollow cylindrical float 1f. Within of the floating body 1f are distributed in the circumferential direction Permanent magnets 1m arranged. The drive device 2 has a cylindrical part 2g, which is fixedly connected to the axis 2b. in the End portion of the part 2g are extending in the circumferential direction Permanent magnets 2 d arranged such that on the between the Permanent magnets 2d and 1 m occurring interaction the Magnetic stirring device 1 in the direction of rotation 1e is set in rotation. moreover is the drive device 2 slidably mounted in the direction 2h, thereby In addition, the vertical position of the magnetic stirring device 1 can be influenced. This radial coupling has the advantage that it only a small destabilizing force on the magnetic stirring device 1, at at the same time good stabilization in the radial direction.

Fig. 20 shows in cross section along the section line E-E the float 1f, within which four permanent magnets 1m distributed in the circumferential direction are arranged. Outside the container 3, the cylindrical part 2g arranged the drive device 2, wherein the part 2g also four Permanent magnets 2d are arranged distributed in the circumferential direction in such a way that between the permanent magnets 1m of the floating body 1f and the permanent magnet 2d of the drive device 2 is a magnetic Clutch is formed.

The container 3 can, as indicated in Fig. 21, as a closed bioreactor be configured, with closable openings 3b and with and Provided discharges 3c.

The floating body 1f could also be fixed and insoluble with the bar 1b be connected. It could also be a set of magnetic stirrers 1 be provided, wherein the float 1f at each Magnetic stirring device 1 at another location on the rod 1b is arranged so that, depending on the liquid level in the container 3 a suitable magnetic stirring device 1 can be selected.

Claims (13)

1. A magnetic stirring device (1) including a stirrer (1a), at least one permanent magnet (1d, 1e), a float body (1f) and a rod (1b), which are connected to one another, wherein the stirrer (1a) is arranged at a first end section (1o) of the bar (1b) and the float body (1f) being arranged at the second end section (1p), characterised in that the magnetic stirring device tapers into a tip (1c) in the region of the first end section (1o).
2. A magnetic stirring device (1) in accordance with claim 1, characterised in that the stirrer (1a) is formed symmetrically; and in that at least two permanent magnets (1d, 1e) are symmetrically arranged in the stirrer (1a).
3. A magnetic stirring device (1) in accordance with any one of the preceding claims, characterised in that the float body (1f) has an increasing inner cross-section in the direction of the second end section (1p) at least along one part section.
4. A magnetic stirring device (1) in accordance with any one of the preceding claims, characterised in that at least one vane (1h) is arranged at the bar (1b).
5. A magnetic stirring device (1) in accordance with any one of the preceding claims, characterised in that a permanent magnet (1m) is arranged in the float body (1f).
6. A magnetic stirring device (1) in accordance with any one of the preceding claims characterised in that the float body (1f) is formed in an annular shape.
7. A magnetic stirring device (1) in accordance with one of the preceding claims, characterised in that the stirrer (1a) is made in a bar shape, in a star shape or in a circular shape.
8. A stirring apparatus (6) comprising a magnetic stirring device (1) in accordance with any one of the preceding claims and also including a magnetic driving apparatus (2), with the driving apparatus and the permanent magnets (1d, 1e) of the magnetic stirring device (1) being mutually arranged and designed so that they form a magnetic coupling.
9. A stirring apparatus (6) in accordance with claim 8, characterised in that the drive apparatus (10) has permanent magnets (2c, 2d) which form a magnetic coupling together with the permanent magnets (1d, 1e) of the magnetic stirring device (1).
10. A stirring apparatus (6) in accordance with claim 8, characterised in that the drive apparatus (10) has a plurality of electromagnetic coils (2f) which form an electric motor together with the permanent magnets (1d, 1e) of the magnetic stirring device (1).
11. A stirring apparatus (6) in accordance with claim 9, characterised in that the permanent magnets (1d, 1e) of the magnetic stirring device (1) and the permanent magnets (2c, 2d) of the drive apparatus (2) are arranged and formed such that they mutually form a passive radial and/or axial magnetic bearing.
12. A stirring apparatus (6) in accordance with one of the claims 8 to 11, characterised in that the magnetic stirring device (1) has a toe bearing.
13. A bio-reactor comprising a magnetic stirring device (1) in accordance with one of the claims 1 to 7 and/or including a stirring apparatus (6) in accordance with one of the claims 8 to 12.

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