EP1188474A1 - Magnetic stirrer - Google Patents

Abstract

A stirring device comprises a magnetic stirring arrangement (1) with a stirrer (1a), permanent magnets (1d, 1e), and a float (1f) connected together; and a magnetic drive (2). The magnetic drive and the permanent magnets are arranged opposite each other and structured so that they form a magnetic coupling. Preferred Features: The drive has permanent magnets (2c, 2d) which form a magnetic coupling together with the permanent magnets of the magnetic stirring arrangement. The drive has a number of electromagnetic coils (2f) which together with the permanent magnets of the magnetic stirring arrangement form an electromotor.

Description

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

Bar magnets are known which are used for stirring liquids can be used by the bar magnet containing a liquid Container is added, and the container onto a rotating magnetic field is set so that the bar magnet is rotated.

A disadvantage of such bar magnets is the fact that they are on the Rest the bottom of the container and therefore only a limited one Generate stirring effect. The one between the bar magnet and the floor Frictional forces can also cause abrasion or in destroy parts of the liquid such as living cells.

The object of the present invention is a more advantageous one Propose magnetic stirring device or a more advantageous stirring device.

This object is achieved with a magnetic stirrer Features of claim 1. Subclaims 2 to 9 relate to further, advantageously designed magnetic stirring devices. The task continues solved with a mixer having the features of claim 10. Die Subclaims 11 to 14 relate to further, advantageously designed Stirrers.

The object is achieved in particular with a magnetic stirring device comprising a stirring part, a permanent magnet and a Floating bodies that are connected to each other.

An essential aspect of the invention is that To design the magnetic stirrer in such a way that the stirrer with respect the bottom of the container is spaced so that the stirring member no longer rotates smoothly on the floor while stirring.

In a preferred embodiment, the magnetic stirring device is elongated, designed essentially rod-shaped, in the area of the first End portion the stirring part and in the area of the second end portion Float is arranged. In a particularly advantageous Design is the end of the first end section as a tip designed. This magnetic stirrer becomes a liquid Containing container added, the magnetic stirrer by the buoyancy forces acting on the floating body in an im essentially vertical alignment is maintained and against one Tilting is stabilized. The floating body thus causes one hydrodynamic stabilization of the magnetic stirrer against one Tilt, and thus stabilizes the magnetic stirrer with respect to two Degrees of freedom.

A device is arranged below the bottom of the container allowed to generate a rotating magnetic field. In a preferred one This device is designed as a magnetic coupling designed a rotating permanent magnet. This Permanent magnet acts on those arranged in the stirring part Permanent magnets. Due to the magnetic coupling designed in this way, the Position of the stirring part and thus the position of the magnetic stirring device with respect three degrees of freedom determined, namely in the x and y direction and with respect of rotation. In the vertical direction or in the direction of the Magnetic stirring device is this through the tip, which together with the Bottom of the container forms a top bearing, only with respect to one Movement down stabilized. Along with the downward acting Magnetic force of the magnetic coupling is also the vertical degree of freedom (z direction) stabilized.

The magnetic stirrer is thus stabilized with respect to 6 degrees of freedom. The known bar magnet mentioned at the beginning is only with reference to FIG. 4 Degrees of freedom stabilized, namely in the x and y directions, with respect to rotation, and, since it lies on the bottom of the container, with regard to movement downward. The magnetic stirring device according to the invention thus has the Advantage on that it is stabilized in terms of more degrees of freedom, what it allows the stirring part to be arranged at a distance from the bottom of the container.

In a further advantageous embodiment, the magnetic stirring device is in the liquid of the container arranged floating, the Magnetic stirrer arranged outside of the container Magnetic field can be driven. The rotating one required for the drive Magnetic field can be generated with the help of electromagnetic coils or with rotatably mounted magnets, especially with rotatably mounted Permanent magnets, which with the magnetic stirrer Form magnetic coupling. In an advantageous embodiment, under Use of the permanent magnets of the magnetic stirrer also Position of the magnetic stirrer influenced by these permanent magnets Form part of a passive magnetic bearing. Part of the passive Magnetic bearing is arranged outside the container and exercises one stabilizing effect on the location of the inside of the container located magnetic stirring device.

The object is further achieved with a mixer Magnetic stirrer with one or more permanent magnets as well a floating body, as well as comprising a magnetic Drive device, the drive device and the Permanent magnets of the magnetic stirring device are mutually adapted in this way are arranged and designed such that they 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 is described below using several exemplary embodiments. Show it:

Fig. 1

a longitudinal section through a mixer with magnetic stirring device lying in the container.

Fig. 1a

a detailed view of the stirring part;

Fig. 1b

a magnetic stirrer with a fully immersed float;

Fig. 2

a longitudinal section through a first mixer with a magnetic stirrer;

Fig. 3

a path-force diagram of the magnetic stirrer;

Fig. 4

a cross section through a floating body;

Fig. 5

a displacement-force diagram of a further magnetic stirring device;

Fig. 6

a longitudinal section through another mixer with magnetic stirring device;

Fig. 7

a longitudinal section through another mixer with magnetic stirring device;

Figures 8a-8f

different arrangements of the permanent magnets of the magnetic stirrer and stirrer;

Fig. 9

a longitudinal section through another mixer with magnetic stirring device;

Fig. 10

a plan view of the drive device shown in Fig. 10;

Fig. 11

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

Fig. 12

a plan view of the electromagnetic coils shown in Fig. 11;

Fig. 13

a longitudinal section through another mixer with magnetic stirring device;

Fig. 14

a cross section through a wing arranged on the magnetic stirring device;

Fig. 15

a longitudinal section through another mixer with magnetic stirring device;

Fig. 16

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

Fig. 17

a longitudinal section through another mixer with magnetic stirring device;

Fig. 18

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

Fig. 19

a longitudinal section through another mixer with magnetic stirring device;

Fig. 20

a cross section through the mixer shown in Figure 19 along the section line EE;

Fig. 21

a mixer in combination with a bioreactor.

1 shows a magnetic stirrer 1 in a longitudinal section a stirring part 1a, a rod 1b and a floating body 1f, which are interconnected. Within the stirring part 1a are, as in Fig. 1a shown in section F-F, two permanent magnets 1d, 1e with respect to Rod 1b arranged symmetrically. The rod 1b ends in a tip 1c, which together with the bottom of the container 3 is a top bearing formed. In the first end section 1o of the rod 1b, the stirring part 1a is light spaced from the tip 1c, so that the stirring part of the bottom of the Container 3 not touched. The floating body is in the second end section 1p 1f arranged. The floating body 1f is in the direction of the rod 1b slidably and with a fastener, not shown, such as a screw can be firmly connected to the rod 1b. The Magnetic stirring device 1 is located in the container 3 located liquid 4 and thereby caused on the floating body 1f Buoyancy force FAZ held in a substantially vertical position. The Floating body 1f thus stabilizes the magnetic stirring device 1 hydrostatic against tilting, so that the position of the Magnet stirrer with respect to two degrees of freedom is hydrostatically stabilized.

A drive device 2 is arranged below the container 3. The Drive device 2 comprises a plate 2a and one in the direction of rotation 2e rotatably mounted axis 2b, two permanent magnets 2c, 2d with the Plate 2a are firmly connected. The permanent magnets 1d, 1e Magnetic stirring device 1 and the permanent magnets 2c, 2d Drive device 2 are arranged such that they are mutually adapted and configured that they mutually form a magnetic coupling to the Drive magnetic stirring device 1 in the direction of rotation 2e. This Magnetic coupling stabilizes the magnetic stirring device 1 with respect to the 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 stirrer 1 stands on the tip bearing 1 c, so that 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 tip bearing and the magnetic attraction between the Permanent magnet 1d, 1e, 2c, 2d is stabilized. Hence the location of the Magnetic stirring device 1 by means shown in FIG. 1 with respect to 6 Degrees of freedom stabilized.

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

In contrast to the arrangement shown in FIG. 1, it is that in FIG. 2 Magnetic stirring device 1 shown in the liquid 4 of the container 3 Hovering as the buoyancy FAZ, as well as the weight the magnetic stirring device 1 and that caused by the magnetic coupling magnetic force are in an equilibrium position. This is the Float 1f in the appropriate position along the rod 1b to arrange. In order to meet this condition, the floating body 1f is open the rod 1b displaceable, so that the position of the floating body 1f depending on the liquid level is adjustable so that the Magnetic stirring device 1 with its tip 1c on the bottom of the container 3 stands. After moving the floating body 1f, this becomes for example, firmly connected to the rod 1b with a screw.

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

The distance between the stirring part 1a and the bottom of the container 3 is represented with the dimension z. Towards the bottom affects the Magnetic stirring device 1 a force FMZ, which results from gravity and the magnetic caused by the drive device 2 Attraction.

Fig. 3 shows the displacement-force diagram of the floating in the liquid Magnetic stirring device 1, wherein the sinking depth z in the abscissa and in the Ordinate the force F is shown. Which by like in a liquid Floating body 1f causes buoyancy force FAZ increases linearly with increasing sinking depth as a function of height h, and increases after the complete immersion of the float 1f one constant value. In addition, the force curve of the FMZ force is a function of Dimension z shown. At the intersection G of the two curves FMZ and FAZ a stable equilibrium is established. In Fig. 3 the difference is the Force FMZ and force FAZ shown as a dashed curve. Between two saddle points, limited by the height of the float, returns the system returns to stable equilibrium G after a fault back. The maximum amount of the difference between FAZ and FMZ is therefore a measure of the robustness of the system. With this measure the last degree of freedom of the magnetic stirrer 1, namely the movement vertically upwards, by the buoyancy together with the opposing magnetic force stabilized so that 3½ Degrees of freedom of the magnetic stirring device 1 are magnetically stabilized, and 2 ½ degrees of freedom of the magnetic stirring device 1 hydrostatically stabilized are.

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

5 shows the weaving force diagram of a magnetic stirring device 1 comprising the floating body 1f shown in FIG. 4. The FMZ force has the same, already shown in Fig. 3. The through the Floating body 1f generated buoyancy force FAZ points along the section h1 exhibits a curved, in particular square, increase in force, whereas the floating body 1f in the cylindrical section h2 causes a linear increase in force. When completely submerged Float 1f, the buoyancy takes a constant value. The stable Equilibrium point G is again at the intersection of the two Curves FAZ and FMZ on. 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 Compared to FIG. 3 the advantage that the magnetic stirring device 1 is more stable the balance can be held. When stirring the liquid, it results namely, due to the acting centrifugal force, the problem that the Liquid level drops in the middle of the container 3, at the edge thereof against it increases. As a result, the float 1f in the container 3 decreases slightly, which in turn means that the distance z is reduced. In this position too, the magnetic stirrer 1 should be contactless in the Container 3 are kept floating. To have stable behavior It is therefore of particular importance that the difference between the forces FMZ and FAZ steadily over a longer section run.

In contrast to the stirrer 6 shown in Fig. 2 are in 6, the permanent magnets 1e, 2c in polarized in the opposite direction.

In contrast to the stirrer 6 shown in Fig. 2 are in Embodiment according to FIG. 7, the permanent magnets 1d, 1e in horizontal direction polarized, whereas the Permanent magnets 2c, 2d of the drive device 2 in the vertical direction and are arranged in opposite polarization.

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

In contrast to the stirring device 6 shown in FIG. 2, the plate 2a 9 has a relatively large diameter on, the permanent magnets 2c, 2d, as in the supervision according to FIG. 10 shown, are designed in the shape of an annular segment. The stirring part 1a is like shown in Fig. 10, cruciform. An advantage of that in FIG. 9 shown arrangement is to be seen in that by the Drive device 2 caused magnetic field in the vertical direction only has a small change, so that a change in position of the Magnetic stirrer 1 in the vertical direction by the Permanent magnets 2c, 2d, 1d, 1e formed a magnetic coupling only has little influence on the coupling behavior.

In contrast to the mixing device 6 shown in FIG. 2, the mixing device shown in FIG. 11 illustrated embodiment, the drive device 2 as one A plurality of bobbins 2f configured, which, as from the in Fig. 12th shown section along the line D-D can be seen in the circumferential direction are regularly spaced to be arranged by a corresponding Control to generate an electromagnetic rotating field. These coils have several advantages. In contrast to permanent magnets, their The closer the stirrer is, the greater the attraction can be with the A constant magnetic field is generated so that the coils Attraction with decreasing distance to the stirring part is not greater becomes. In addition, the magnetic field strength is via the current of the coils adjustable. This has a stabilizing influence on the location of the Magnetic stirring device.

In contrast to the stirrer 6 shown in FIG. 2, the Magnetic stirring device 1 in the embodiment shown in FIG. 13 three vanes or blades spaced apart in the vertical direction 1h, 1i, 1k. This allows the rotational forces of the magnetic stirring device 1 even better to transfer to the liquid 4. The one shown in Fig. 14 Section along the line C-C shows the cross-shaped wing 1h on average. In addition, the cruciform wing arranged below as well the bottom arranged stirring part 1a is shown.

In contrast to the stirrer 6 shown in FIG. 2, the stirrer 6 shown in FIG magnetic stirrer 1 shown has an additional blade 1h, which is firmly connected to the rod 1b. This wing 1h serves the rotating forces acting on the magnetic stirrer better on the Transfer liquid 4. Stirring the liquid 4 causes the Liquid level 4a rises at the edge of the container 3, whereas the Liquid level 4a drops in the middle, which has the consequence that the Magnetic stirring device 1 drops. The change in the liquid level 4a or the speed of rotation 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 are arranged become.

In contrast to the mixing device 6 shown in FIG. 2, the mixing device shown in FIG Magnetic stirring device 1 shown a ring-shaped Floating body 1f, which is connected to the rod via a connecting means 1l 1b is connected. The arrangement and design of the floating body 1f is chosen in such a way that the changes during stirring Liquid level 4a not or only slightly to the level of Magnetic stirring device 1 affects. By stirring the liquid 4 points this shows the surface course designated 4a.

The magnetic stirring device 1 has a relatively high mass and is therefore difficult in the radial direction by the drive device 2 to keep. Therefore, the floating body 1f is advantageously equipped with a additional device stabilized. These are within the Floating body 1f running in the circumferential direction permanent magnets 1m arranged. In addition, outside of the container 3 is a Moving direction 5f movable adjusting device 5 arranged, which has permanent magnets 5a, 5b arranged distributed in the circumferential direction. The permanent magnets 5a, 5b are such with respect to the permanent magnets 1m arranged that by moving the Adjustment device 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 one Position of the float 1f with the permanent magnet 1m, 5a, 5b formed passive radial magnetic bearings in addition to stabilize.

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

The mixer 6 shown in a longitudinal section in FIG. 19 has one Magnetic stirrer 1, which is a circular Stirring part 1a, which is fixed with a hollow cylindrical Float 1f is connected. Within the float 1f are in Distributed permanent magnets 1m arranged circumferentially. The Drive device 2 has a cylindrical part 2g, which with the Axis 2b is firmly connected. In the end section of part 2g are in Circumferential direction permanent magnets 2d arranged such that over the occurring between the permanent magnets 2d and 1 m Interaction of the magnetic stirrer 1 in the direction of rotation 1e in rotation is relocatable. In addition, the drive device 2 is in the direction 2h slidably mounted, which also makes the vertical position of the Magnetic stirring device 1 can be influenced. This radial clutch has the Advantage on that they have only a small destabilizing force on the Exercises magnetic stirring device 1 with good stabilization at the same time radial direction.

20 shows the floating body in cross section along the section line E-E 1f, within which four permanent magnets 1m are distributed in the circumferential direction are arranged. Outside the container 3 is the cylindrical part 2g the drive device 2 arranged, with 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 float 1f and the permanent magnet 2d of the drive device 2 is magnetic Coupling is formed.

The container 3 can, as indicated in Fig. 21, as a closed bioreactor be designed with closable openings 3b and with feed and Provide derivatives 3c.

The floating body 1f could also be fixed and non-detachable with the rod 1b be connected. A set of magnetic stirring devices 1 could also be used be provided, the floating body 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 (15)

Magnetic stirring device (1) comprising a stirring part (1a), at least a permanent magnet (1d, 1e) and a floating body (1f), which are connected to each other. Magnetic stirring device (1) comprising a rod (1b), the first End section (1o) of the rod (1b), the stirring part (1a) and the second End section (1p) of the floating body (1f) is arranged. Magnetic stirring device (1) according to one of the preceding claims, characterized in that it ends in the region of the first end section (10) in a tip (1c). Magnetic stirring device (1) according to one of the preceding claims, characterized in that the stirring part (1a) is symmetrical, and that at least two permanent magnets (1d, 1e) are arranged symmetrically in the stirring part (1a). Magnetic stirring device (1) according to one of the preceding claims, characterized in that the floating body (1f) has an increasing internal cross section in the direction of the second end section (1p) at least along a partial section. Magnetic stirring device (1) according to one of the preceding claims, characterized in that at least one wing (1h) is arranged on the rod (1b). Magnetic stirring device (1) according to one of the preceding claims, characterized in that a permanent magnet (1m) is arranged in the floating body (1f). Magnetic stirring device (1) according to one of the preceding claims, characterized in that the floating body (1f) is designed in a ring shape. Magnetic stirring device (1) according to one of the preceding claims, characterized in that the stirring part (1a) is rod-shaped, star-shaped or circular. Mixing device (6) comprising a magnetic stirring device (1) with a Permanent magnet (1d, 1e) and a floating body (1f), in particular a magnetic stirring device (1) according to one of the preceding claims, and comprising a magnetic Drive device (2), wherein the drive device (2) and the Permanent magnets (1d, 1e) of the magnetic stirring device (1) in this way are mutually adapted and designed so that they are a Form magnetic coupling. Mixing device (6) according to claim 10, characterized in that the drive device (2) has permanent magnets (2c, 2d) which, together with the permanent magnets (1d, 1e) of the magnetic stirring device (1), form a magnetic coupling. Mixing device (6) according to claim 10, characterized in that the drive device (2) has a plurality of electromagnetic coils (2f) which, together with the permanent magnets (1d, 1e) of the magnetic stirring device (1), form an electric motor. Mixing device (6) according to claim 11, characterized in that the permanent magnets (1d, 1e) of the magnetic stirring device (1) and the permanent magnets (2c, 2d) of the drive device (2) are arranged and designed such that they mutually a passive radial and / or form axial magnetic bearings. Mixing device (6) according to one of claims 10 to 13, characterized in that the magnetic stirring device (1) has a tip bearing. Bioreactor comprising a magnetic stirring device (1) according to one of the Claims 1 to 9 and / or comprising a stirrer (6) according to one of claims 10 to 14.

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