WO2017046235A1

WO2017046235A1 - Magnetic separating device with mechanical activation and deactivation

Info

Publication number: WO2017046235A1
Application number: PCT/EP2016/071805
Authority: WO
Inventors: Martin Gajewski; Hanspeter Romer; Mario Arangio
Original assignee: Hamilton Bonaduz Ag
Priority date: 2015-09-18
Filing date: 2016-09-15
Publication date: 2017-03-23
Also published as: EP3349910A1; DE102015218008A1; EP3349910B1

Abstract

On a magnetic separating device (10) for separating magnetic particles from a suspension (14) with a soft magnetic tip (16) which extends along a tip axis (S) and the magnetization state of which can be selectively changed between a more strongly magnetized state and a more weakly magnetized state, the tip (16) has an immersion end (16a) for insertion into the suspension (14) and a magnetizing section (16b) for changing the magnetization state of the tip (16), wherein the separating device (10) has a movement drive and a magnet arrangement (32) which is connected thereto in such a way that movement is transmitted, which comprises at least one permanent magnet or is formed by at least one permanent magnet and which can be moved towards or away from the magnetizing section (16b) by the movement drive so that the magnetic field of the magnet arrangement (32) can be varied over time in the magnetizing section (16b) of the tip (16) for changing the magnetization state of the tip (16). According to the invention, the soft magnetic tip (16) can rotate about the tip axis (S).

Description

Magnetic separation device with mechanical activation and

deactivation

description

The present invention relates to a magnetic separation device for separating magnetic particles from a suspension having a soft magnetic tip extending along a tip axis whose magnetization state is selectively changeable between a more magnetized state and a weaker magnetized state, wherein the tip is an immersion end to Introduction into the suspension and a magnetization section for changing the magnetization state of the tip, wherein the separation device comprises a movement drive and with this motion-communicating magnetic arrangement comprising at least one permanent magnet or at least one permanent magnet is formed and which by the movement drive to the magnetization section approachable and removable from, so that the magnetic field of the magnet assembly in the magnetization portion of the tip to change the magnetization and the tip is temporally variable. Such separation devices are used, for example, in chemical, biochemical and / or pharmaceutical laboratories to remove magnetic particles contained in a suspension from the suspension.

Such suspensions with magnetic particles can be used for example for the purification of DNA. The magnetic particles serve merely as a means of transport and are usually coated in such a way that only a specific constituent of the suspension can and will attach to the outer surface of the coating pointing away from the particle, which can then be removed together with the particle from the suspension. The magnetic particles are thus usually magnetic only for the purpose of the planned removal of chemical or biological material from the suspension liquid. By "magnetic" is meant a material which is either magnetizable or magnetised. In most applications of the magnetic separation device discussed herein, the magnetic particles will comprise ferromagnetic material or be made of ferromagnetic material.

A generic magnetic separation device is known from US 7799281 B2. This document discloses a magnetic separator having a soft magnetic tip which is rigidly coupled at its longitudinal end remote from the dip end to a guide tube in which a permanent magnet is approachable along the tube axis to contact the soft magnetic tip and removable therefrom.

The movable permanent magnet is polarized along its axis of motion so that one of its magnetic poles can be brought into contact contact with the soft magnetic tip. For the duration of the touch contact, the soft magnetic tip is magnetized while, when the permanent magnet is spaced from the soft magnetic tip, it is substantially unmagnetized. That portion of the soft magnetic tip which makes contact with the movable permanent magnet is the magnetization portion of the known soft magnetic tip. The known generic magnetic separation device thus comes in the region of its soft magnetic tip without electrically energized components, in particular without an electromagnet, which often represents an undesirable heat source magnetic separation devices. The coincident with the axis of the guide tube relative movement direction of the permanent magnet is collinear with the tip axis to provide a radially as possible with respect to the tip axis as slim magnetic separation device. The permanent magnet is coupled with its movement drive via a rod accommodated in the guide tube and extending coaxially with the guide tube or via a cable received in the guide tube and running coaxially with the guide tube, and thus driven for movement within the guide tube. bar. Further mobility of the permanent magnet and the soft-elastic tip is not provided.

A further magnetic separation device which, however, uses an electromagnet to be energized for the duration of the magnetization for the temporary magnetization of the soft-magnetic tip, is known, for example, from WO 02/40173 A1. In this known separation device, a strong and correspondingly space-demanding electric ring magnet surrounds the soft-magnetic tip, which passes through the plane of extent of the electric ring magnet along the ring axis.

In the case of energization of the electric ring magnet which passes through it soft magnetic tip acts as an anchor or iron core and is magnetized for the duration of energization of the electric ring magnet, so that the insertion end of the soft magnetic tip inserted into the respective suspension and then because of their magnetized state in the suspension contained magnetic particles attract until it rests against an outer surface of the soft magnetic tip and then can remove frictionally or non-positively from the remaining suspension liquid. The outer surface of the soft magnetic tip may be formed by the soft magnetic material itself or - depending on the requirements of the respective cleaning process - by a surrounding the insertion end of the soft magnetic tip protective cover.

At its longitudinal end opposite the immersion end, the magnetic separation device known from WO 02/40173 A1 is coupled to an electromotive rotary drive, by means of which the soft-magnetic tip is rotatable about its longitudinal axis. The coupling of the soft-magnetic tip with a rotary drive is readily possible for the magnetic separation device known from WO 02/40173 A1, since the magnetic ring magnet changing the magnetization state of the tip can interact with the tip without contact and thus does not disturb its rotational drive coupling. By rotation of the soft magnetic tip can be supported by WO 02/40173 A1, the deposition of the particles at magnetized immersion end of the soft magnetic tip. The rotation may also be used to remove magnetic particles deposited from the immersion end of the soft magnetic tip and removed from the suspension liquid together with the soft magnetic tip from the dip end.

A disadvantage of the known from WO 02/40173 A1 magnetic separation device is on the one hand their expansive space-demanding design in which the soft magnetic tip and the electric ring magnet are arranged coaxially and axially overlapping as the above-mentioned magnet assembly. Another device, in particular a further magnetic separation device can therefore not be approximated closer to the known separation device than the radius of the soft magnetic tip surrounding the electric ring magnet. On the other hand, the use of an electromagnet for temporary magnetization of the soft-magnetic tip can be questionable, in particular if the electromagnet for magnetizing the soft magnetic tip is to be arranged axially overlapping with this in the direction of its longitudinal axis. The electromagnet is thus arranged comparatively close to the suspension to be processed with the separating device. Since the electromagnet only provides its magnetic field when energized, heating of the electromagnet and thus at least the risk of thermal loading of the suspension to be processed occurs during operation of the magnetic separation device, which may be disadvantageous for thermally sensitive ingredients of the suspension.

The object of the present invention is to further improve the functionality of the magnetic separation device mentioned above.

This object is achieved by a generic magnetic separation device in which the soft magnetic tip is rotatable about the tip axis. Due to the rotatability of the soft magnetic tip about the tip axis, centrifugal forces acting radially to the tip axis can be generated at the soft magnetic tip. As a result of these centrifugal forces, magnetic particles adhering to the soft-magnetic tip can be removed therefrom and / or residual magnetic fluid present on the magnetic particles adhering to the tip can be removed from the magnetic particles.

Preferably, the speed at which the tip axis is rotatable, adjustable or changeable to adjust the acting centrifugal forces.

For example, the soft magnetic tip may be rotatable when in its more magnetized magnetization state in which a higher magnetic force acts between the soft magnetic tip and magnetic particles adhered thereto, so that suspension liquid flows from the magnetic particles adhered to the tip by rotation of the soft magnetic tip can be deposited. This is successfully possible if the centrifugal forces acting thereon due to the rotation of the soft magnetic tip between it and the magnetic particles are less than the magnetic forces acting on the basis of the magnetization state of the tip.

Alternatively or additionally, the soft-magnetic tip can be rotatable in its weakly magnetized magnetization state, wherein the weakly magnetized magnetization state can be, in particular, a state of missing magnetization, that is, an un- or demagnetized state. In this case, the centrifugal forces caused by rotation of the tip can outweigh those forces with which magnetic particles previously removed from a suspension adhere to the soft magnetic tip. In the presence of the weakly magnetized state of the soft magnetic tip, these may be weak magnetic forces and / or adhesion forces due to still existing residues of suspension liquid.

Basically, it can be thought of separate motion drives for the approach movement and removal movement of the magnet assembly to the soft magnetic tip towards or away from this on the one hand and for the rotation of the soft magnetic tip about its tip axis on the other hand provide. It is more advantageous, however, to provide only one movement drive for both movements. According to an advantageous embodiment of the present invention, the movement drive can be both coupled with the magnet assembly to transmit these to their approach movement to the magnetization section and to their removal movement away from this, and is also coupled to the soft magnetic tip to transmit it in order to rotate around to drive the top axle. Thus, the magnetic separation device can manage with a single motion drive.

In principle, it can be thought of coupling the magnet assembly to be driven by the movement drive for movement directly to the drive. Preferably, however, this coupling is carried out with the intermediate arrangement of a transmission in order to implement speeds and forces or torques on the output side of the movement drive in suitable for the magnet assembly and the movement desired by them speeds and forces or torques. Furthermore, the transmission may be suitable for converting a movement type of an output member of the movement drive into another type of movement of the movement desired by the magnet arrangement, for example converting a rotational movement of the output member into a translatory movement of the magnet arrangement.

A preferred transmission, which meets the above requirements and in addition allows a radially with respect to the tip axis slim design of the magnetic separation device is a screw drive. A screw drive allows the implementation of rotational movement of an output member of a motion drive, such as an output shaft and thereby allows the use of spatially compact motion drives. By appropriate selection of the thread pitch of the threaded drive, the forces which act on the magnet arrangement as a function of the output values of the movement drive and the speeds which can be achieved by the latter can be set. Next, the screw can be advantageously carried out self-locking, so that movement and force only from one side ago, in this case from the side of the movement drive ago, can be introduced into the device.

Since for the magnet assembly to achieve a radially slender design of the magnetic separator usually a collinear trajectory is desired with the tip axis, it is advantageous if a threaded axis of a thread of the screw bearing threaded member, such as a threaded rod, is collinear with the tip axis. Constructively, the screw to achieve the above-mentioned desired radially slender design and to reduce the components required for forming the magnetic separation device may be formed such that it has a connected for common rotation with the soft-elastic tip threaded rod, which passes through the magnet assembly, said Magnetic arrangement can be coupled for common movement with a threaded nut of the screw drive or - preferably - part of the threaded nut of the screw drive is. The magnet arrangement can, for example, have one or more annular permanent magnets, which are coupled radially inward for common movement with a sleeve, on the inside of which an internal thread is formed. The internal thread can be screwed with the threaded rod.

Further, the magnetic separation device may have a frame, which is to serve for further discussion as a coordinate origin of a stationary coordinate system. For example, usually the movement drive rests relative to the frame. However, the frame as a whole may in turn be movable relative to a superordinate structure, such as a machine carrying the magnetic separation device, for instance in order to lower the magnetic separation device into a suspension and lift it out of suspension. To ensure the function of the threaded nut, which is preferably formed with the involvement of the magnet arrangement, rotation prevention, for example in the form of a slotted guide, is provided, as is customary in screw drives, which prevents relative rotation of the threaded nut about the threaded axis of the threaded rod. dert, so that a rotation of the threaded rod sure leads to a translational displacement of the threaded nut along the threaded axis.

In principle, however, it should not be ruled out that the magnet arrangement is provided separately from the threaded nut and is coupled thereto for common translatory movement, although this is not preferred.

Although the soft elastic tip may be coupled to the threaded rod for common rotation with the interposition of another gear, "common" is then broadly understood to mean that the soft elastic tip rotates at least when the threaded rod rotates, for the sake of simplicity Slender construction is preferred when the threaded rod is rigidly coupled to the soft-elastic tip for common rotation, so that the rotation of the tip and the rotation of the threaded rod in rotational speed and sense of rotation match and the tip only rotates when the threaded rod is rotated ,

As a rule, the tip axis runs in the direction of gravity, to which the surface of the suspension, into which the tip is lowered, is naturally orthogonal. Then, the approaching movement of the magnet assembly to the soft magnetic tip is usually assisted by gravity, while the removal movement of the magnet assembly must be to remove it from the soft magnetic tip against gravity. Basically, the location of the maximum distance of the magnet assembly from the tip may be determined by a mechanical stop against which the magnet assembly is moved. However, when using the gear drive preferred with a single motion drive, the use of an abutment to define this location may impede the rotatability of the threaded rod and thus, typically, the soft magnetic tip when the magnet assembly stops at the maximum removal location has reached and the magnet assembly is not to be approximated to the soft magnetic tip again. However, the location of the maximum removal of the magnet assembly can be easily defined using a threaded drive through the threaded end of the threaded rod itself. A mechanical end stop is therefore not needed at the point of maximum removal of the magnet assembly from the tip. Therefore, the rotatability of the soft magnetic tip can be maintained even if the magnet assembly is maximally remote therefrom, if the magnetic separation device is preferably configured such that the maximum distance of the magnet assembly from the tip is defined by a threaded end of the threaded rod, between Threaded end and the movement drive is arranged a rod intermediate portion at which the magnet assembly is out of engagement with a threaded portion of the threaded rod and remains with continued rotation of the threaded rod in the removal direction at substantially the same distance from the soft-elastic tip. In other words, the threaded nut of the screw drive and with this the magnet assembly are simply unscrewed from the threaded portion of the threaded rod, so that further rotation of the threaded rod in the sense of removal of the magnet assembly from the tip due to lack of engagement between the threaded rod and threaded nut to no further removal movement Threaded nut leads. The threaded rod can be made in one or more parts, for example comprising a threaded component with external thread and an idle component with the above-mentioned rod intermediate section.

Due to the fact that the threaded nut bears against the tip-remote threaded end of the threaded rod, the threaded engagement between threaded rod and threaded nut can be restored when the direction of rotation of the threaded rod changes and the threaded nut and, with it, the magnet arrangement can be approximated to the soft-magnetic tip again. This applies in particular if the threaded axis of the threaded rod has a component in the direction of gravity action, preferably in the direction of gravity action.

As has already been explained above, in order to achieve a cutting device which is as slender as possible radially, a rod axis along which the threaded rod extends extends, collinear with the tip axis. The rod axis coincides with the aforementioned thread axis.

The location of maximum approximation of the magnet arrangement to the tip can be formed by a stop on which the magnet arrangement rests in the more magnetized state of the tip. This stop can also be formed by a section, in particular the magnetization section, of the tip itself. However, it may also be formed by an intermediate component which is arranged between the magnet arrangement and the soft-magnetic tip. For most effective magnetization of the soft magnetic tip with maximum approximation of the magnet assembly to it such intermediate member is preferably at least partially made of soft elastic material, preferably completely made of flexible material. Then, when the magnet assembly is prevented by abutment against the stop on a further approach movement, to prevent damage to the separating device, the movement drive for further operation in the approach sense be locked. However, this has the consequence that rotation of the soft-magnetic tip is then possible only with simultaneous removal movement of the magnet arrangement away from the soft-magnetic tip, since only this direction of rotation of the movement drive in the contact state of the magnet arrangement is possible at the stop close to the soft-magnetic tip.

If the rotatability of the soft magnetic tip is desired even at maximum approximated to it magnet assembly may be arranged in the torque transmission path between the movement drive and magnet assembly, a force or torque-dependent coupling, which, for example, then prevents further torque transmission from the motion drive to the magnet assembly in the proximity sense, if the soft magnetic tip is maximally approximated to the magnet assembly and the movement drive is operated in the proximity sense. For example, the clutch can be designed such that it transmits force and / or torque on the threaded nut of the screw drive and / or on the magnet arrangement when falling below a predetermined release torque and that they are on the release torque no force and / or no torque on the Threaded nut and / or transfers to the magnet assembly. In this case, the threaded rod and with it the tip on reaching the end stop at the location of maximum approximation of the magnet assembly to the soft magnetic tip in the direction of approach continue to rotate without causing a displacement of the threaded nut and with this the magnet assembly in the direction of approach.

Such a coupling can be provided, for example, radially between the above-mentioned sleeve carrying an internal thread and the at least one ring-shaped permanent magnet of the magnet arrangement surrounding this sleeve radially on the outside. The clutch may be a slip clutch or the like.

In order to provide a magnetic field which is as homogeneous as possible, it is preferable for the magnet arrangement to be rotationally symmetrical at least in sections, preferably completely.

In the above-described advantageous example of an embodiment of the magnetic separation device according to the invention, the magnet arrangement can cause its maximum magnetization at maximum approach to the soft magnetic tip, so that the magnetic field of the magnet assembly is the magnetic field magnetizing the soft magnetic tip.

However, it can also be thought that the magnetic field of the above-mentioned magnet arrangement is merely a control magnetic field which weakens a magnetization magnetic field of another magnet arrangement differently depending on the relative position of the first-mentioned movable magnet arrangement relative to the soft magnetic peak. In this case, the magnetization of the soft magnetic tip is caused by the magnetic field of the further magnet arrangement, wherein the magnetic field can be influenced by the magnetic field of the first-mentioned movable magnet arrangement.

Thus, the magnetic separator may comprise a second magnet assembly permanently connected to the soft magnetic tip, wherein the tip-to-tip magnet assembly in the approximated magnetization portion weakens the magnetic field of the second magnet assembly more than in the farther tip distant condition. The second magnet arrangement is the above-mentioned further magnet arrangement. The so far described alone approachable and removable from this magnet assembly is referred to as a first magnet assembly. The permanent connection of the second magnet arrangement with the soft magnetic tip can then be advantageously designed for the intended magnetization of the soft magnetic tip, for example by the magnetization section of the soft magnetic tip surrounding, preferably pot-like, the second magnet arrangement at its end section closest to the soft magnetic tip.

For the above-mentioned reasons, the second magnet arrangement is preferably configured at least in sections, particularly preferably completely rotationally symmetrical. Likewise, the second magnet arrangement also preferably extends along an arrangement axis, which is preferably its rotational symmetry axis and which is collinear with the tip axis.

A desired radially slender configuration of the magnetic separation device can be achieved in that the second magnet arrangement passes through the movable, ie the approachable and removable, first magnet arrangement.

This can be solved structurally space-saving particularly simple in that the second magnet assembly is part of the threaded rod. For example, the second magnet arrangement may be surrounded as a cylindrical bar magnet by a radially outer cylindrical sleeve which carries an external thread. Although in principle it is also conceivable to form the external thread of the threaded rod directly on the second magnet arrangement, however, numerous are suitable for perma- Magnets preferred materials very brittle, so that a thread formation on the outside of a magnet assembly is likely to be associated with difficulties. A possible weakening of the magnetic field of the second magnet arrangement as a function of the relative position of the first magnet arrangement relative to the soft magnetic tip and thus also relative to the second magnet arrangement can be effected by arranging the first magnet arrangement and the second magnet arrangement coaxially with opposite polarization, with their respective magnetic field Poles follow each other along the common extension axis. In this case, unlike poles of the first and the second magnet arrangement are in the position of closest approach of the first magnet assembly to the soft magnetic tip very close together, so that by the first magnet assembly, a magnetic inference can be effected and thus only a small part of the magnetic field of the second magnet assembly actually penetrates into the soft magnetic tip.

In the state of greatest distance of the first magnet arrangement from the magnetization section of the soft magnetic tip and the longitudinal end of the second magnet arrangement closest thereto, at least no such magnetic inference is present anymore, so that the magnetic field provided by the second magnet arrangement at its tip-closer longitudinal end concentrates on the soft magnetic material of the tip can be. Thus, when the first magnet assembly is at a maximum distance therefrom, the soft magnetic tip may have its magnetization state of greatest magnetization.

Preferably, in order to increase the number of suspensions which can be processed simultaneously, the magnetic separation device comprises a separator head having a plurality of soft magnetic tips, all extending along a tip axis, the tip axes of the individual soft magnetic tips being arranged parallel to one another. Preferably, the soft magnetic tips are arranged in a matrix-like manner in rows and columns, wherein an orthogonal row and column system is preferred. In order to be able to process different suspensions simultaneously with such a separating device head, the magnetization state of at least part of the soft magnetic tips of the separating pre-emergence head can preferably be changed independently of another part of the soft magnetic tips. This independent variability of the magnetization state of soft magnetic tips in a separator head can be accomplished by individual movement of the magnet assembly that can be approached and removed from the soft magnetic tip.

Preferably, the magnetization state of each individual soft-magnetic tip of the separation pre-head is changeable independently of the magnetization state of each other soft-magnetic tip. Since the change in the magnetization state is preferably effected by energizing an electromotive movement drive of the movable magnet arrangement, the energization of individual movement drives can be effected in a simple and reliable manner by a corresponding control device, wherein the control device can also be designed to line up soft-magnetic tips of the separation device head. or / and column by column to jointly change the magnetization state summarize. In this case, the control device can change all soft magnetic peaks of a row and / or a column by common control of the respective movement drives the movable magnet assemblies in the same sense and simultaneously.

Such magnetic separation devices can advantageously be provided on a pipetting device, in which case at least one pipetting channel of the pipetting device is replaced by a separating device as described above. The technical features presented above for forming a radially slimmest possible separation device make it possible to form the magnetic separation device of the present invention with a radial installation space requirement which does not exceed that of a pipetting channel in a pipetting device. Preferably has a like Separator described above formed a radial extent of less than 20 mm, preferably not more than 18 mm.

The soft magnetic tip may be metallic bright or may have a coating. The coating may be fixedly connected to the magnetic tip or may be detachably provided thereon.

The movement drive of the movable magnet arrangement is preferably provided with the greatest possible distance from the soft magnetic tip, and in particular from its insertion end, of the respective separation device. Therefore, the first and / or the second magnet arrangement is preferably arranged between the movement drive and the soft-magnetic tip.

The heat source present by the preferred electromagnetic motion drive is negligible in its effect on the suspension to be processed not only because of the greatest possible distance of the motive drive from the plunge end of the soft magnetic tip, but also because the motive drive is only for the duration of the change in magnetization state the soft magnetic tip needs to be energized, but not for the duration of the magnetization state itself.

The present invention will be explained in more detail with reference to the accompanying drawings. 1 a is an elevational view of an embodiment according to the invention of a magnetic separation device of the present application,

1 b is a longitudinal sectional view of the device of FIG. 1 a taken along the section plane Ib-Ib in FIG. 1 a, wherein the movable magnet arrangement is in its end position closest to the soft-magnetic tip, Figure 2a is a view corresponding to the view of Figure 1 a same device, wherein the movable magnet assembly is in its off-peak end position, and Figure 2b is a longitudinal sectional view of the device of Figure 2a taken along the sectional plane llb-llb in Figure 2a.

In FIGS. 1 and 2, an embodiment according to the invention of a magnetic separating device with mechanical drive is generally designated 10. The separating device 10 extends along a device axis V, which is preferably oriented parallel to the direction of gravity of action in normal operation and intended arrangement.

Below the magnetic separation device 10 is a container 12 in which a suspension 14 (see FIGS. 1 b and 2 b) is accommodated, in which magnetic particles are suspended in a suspension liquid for the purpose of biochemical analysis.

The magnetic separator 10 comprises, in a manner known per se, a soft-magnetic tip 16 which extends along a tip axis S which is collinear with the device axis V. The soft-magnetic tip has a longitudinal end 16a located closer to the container 12 during normal operation, which is an insertion end 16a of the tip 16, since the tip 16 is immersed in the suspension 14 with this insertion end 16a, in order then to reach Magnetization of the tip 16 magnetic particles from the suspension 14 to remove. The magnetic particles of the suspension 14 are attracted by the increased magnetization of the soft magnetic tip 16 of this and can be removed under the action of the forces acting on the magnetic particles magnetic forces with the tip 16 at this adhering to the suspension 14. To protect the soft magnetic tip 16, this may be wrapped by a releasably surrounding the tip 16 protective sheath 18. The protective cover 18 may be formed of plastic or of a non-magnetic metal. The longitudinal end 16b of the tip 16 opposite the plunging end 16a forms a magnetization section 16b of the soft magnetic tip since, as will be described in detail below, the temporary magnetization of the tip 16 is effected via this section 16b or longitudinal end. The magnetization section 16b is surrounded by a coupling component 20 which projects beyond the longitudinal end 16b, axially with respect to the device axis V, away from the insertion end 16a.

The coupling member 20 couples the soft magnetic tip 16 for common rotation with a drive member 24 whose tip nearer longitudinal end 14 a is also surrounded by the coupling member 20.

At its opposite, tip-distal longitudinal end, the drive member 24 has a stub shaft portion 24b, which is designed for coupling to a drive motor, not shown in Figures 1 and 2. For this purpose, the stub shaft portion 24b has an axial recess 26 into which a key for torque transmission from a hub of a drive motor, not shown in Figures 1 and 2 can be inserted to positively transfer torque to the stub shaft portion 24b and thus to the drive member 24. The drive member 24 is integrally formed in the example shown, but this need not be so.

A portion 24c of the drive member 24 is provided with an external thread 28 and forms a threaded rod portion.

Above the threaded rod portion 24c, axially adjacent thereto immediately thereafter, there is an externally threaded intermediate rod portion 24d. Of the Threaded rod portion 24c and the intermediate rod portion 24d preferably have a smaller diameter than the shaft stub portion 24b.

The drive component 24 extends along a component axis B, which is also collinear with the device axis V. Preferably, the drive member 24 - with the exception of the feather key recess 26 and the external thread 28 - rotationally symmetrical with respect to the device axis V is formed.

Preferably, also the coupling component 20 is rotationally symmetrical to the device axis V. The coupling member 20 may connect the tip 16 and the drive member 24 by, for example, press-fitting both components in the central recess of the coupling member 20 for common rotation about the device axis V. The drive member 24 passes through a threaded nut 30, which is coupled for common movement with a permanent magnet assembly 32, for example by gluing.

A nose 30a of the threaded nut 30, which projects radially with respect to the device axis V from the remaining gear nut body, protrudes into an axially long and narrow in the circumferential direction about the device axis V guide recess 34 of a frame 36 inside. This positive engagement of the nose 30a in the slot recess 34 forms a rotation prevention of the threaded nut 30 about the device axis V, so that upon rotation of the drive member 24, the threaded nut 30 and with it the permanent magnet assembly 32 connected to it for co-movement securely translatable along the device axis V over the region of the threaded rod portion 24c away are displaced.

The threaded nut 30 and the coupling component 20 as well as the soft-magnetic tip 16 in the illustrated example of soft magnetic material. The drive component is preferably non-magnetic in the example shown. Then, when the threaded nut 30 and with it the permanent magnet assembly 32 is located at its tip 16 nearest location, the permanently connected to the permanent magnet assembly 32 in touching contact threaded nut 30 is in touching contact with the coupling member 20, which in turn by the above-mentioned interference fit is in touching contact with the magnetization portion 16b of the soft magnetic tip 16. In the state shown in FIGS. 1 a and 1 b, the soft magnetic tip 16 is therefore magnetized by the permanent magnet arrangement 32 or by the magnetic field originating therefrom. It is at least more magnetized than in the state shown in Figures 2a and 2b of the device 10, in which the permanent magnet assembly 32 is located at its furthest from the top 16 location.

In this case, the coupling component 20 can form a mechanical end stop for the threaded nut 30 or for a jointly movable arrangement of threaded nut 30 and permanent magnet arrangement 32. Then, when the threaded nut 30 is applied to the coupling member 20, as shown in Figure 1 b, in the example shown further rotation of the drive member 24 in an approximation of the threaded nut 30 to the soft magnetic tip 16 is impossible, since the nut 30 is already maximum is approximated to the top 16.

In this state, the soft magnetic tip 16 can only be rotated when the drive member 24 is rotated in a distance sense in which the threaded nut 30 is removed from the tip 16 along the device axis V. Alternatively, the threaded nut 30 may have a torque-dependent coupling, such as a slip clutch or the like., Which allows further rotation of the drive member 24 in the proximity sense even when the threaded nut 30 abuts the end stop formed by the coupling member 20 and is at maximum approximate to the tip 16.

In FIGS. 2 a and 2 b, the magnetic separation device 10 is shown at the demagnetized tip 16 or at the weaker magnetized tip 16. For this purpose, starting from the state shown in FIGS. 1a and 1b, the Drive member 24 as long as the Vorhchtungsachse V in the sense of distance rotated until the gear nut 30 has been moved axially out of the threaded rod portion 24c and thus this is no longer in screw engagement with the threaded rod portion 24c. As a result, the drive component 24 can be further rotated in the direction of removal, without there being any further displacement of the threaded nut 30 and with this the permanent magnet arrangement 32 away from the soft-magnetic tip 16.

However, due to the direction of gravity parallel to the device axis V towards the container 12, a rotational direction reversal of the rotational movement of the drive member 24 suffices to cause the nut 30 to again screw into engagement with the threaded rod portion 24c of the drive member 24 and again by further rotation of the drive member 24 in the approximation can be approximated to the soft magnetic tip 16.

The magnetic separation device 10 thus allows a radially extremely slim design, which is suitable for an arrangement of a plurality of separation devices 10 in a matrix structure with parallel device axes V. Further, the magnetic separator 10 not only permits the targeted change of the magnetization state of the soft magnetic tip 16 between a more magnetized state and a less strongly magnetized state, but moreover permits a rotation of the soft magnetic tip 16 about its tip axis S, which coincides with the device axis V. Returning to FIG. 1 b, an alternative embodiment is briefly presented:

Coaxially with the threaded rod section 24c, a further permanent magnet arrangement 40 'can be accommodated therein. In this case, preferably at least the coupling section 24a of the drive component 24 is formed from soft magnetic material in order to achieve a magnetic closure of the second permanent magnet arrangement 40 'via the coupling longitudinal end 24a and the coupling component 20 with the magnetization section 16b. The coupling portion 24a touches Preferably, the magnetization portion 16b frontally, so that there is a direct magnetic circuit between these components. The coupling portion 24a formed of soft magnetic material therefore extends to the second permanent magnet assembly 40 'and is in contact with it. Preferably, the entire threaded rod portion 24c or even the entire drive member 24 is formed of soft magnetic material.

In this case, both the permanent magnet arrangement 32, which is then to be referred to as the first permanent magnet arrangement, and the second permanent magnet arrangement 40 'are magnetized such that their magnetic poles follow one another along the device axis V. The polarization directions of the two permanent magnet arrangements 32 and 40 'are directed exactly opposite.

In this case, the first permanent magnet arrangement 32 weakens the magnetic field of the second permanent magnet arrangement 40 'in the region of the pole end closest to the tip 16 by field closure in the position approximated to the peak 16 shown in FIG. The unlike pole of the first permanent arrangement 32 lying close to the pole of the second permanent arrangement 40 'at the magnetization section 16b provides a magnetic inference for the magnetic field emanating from the pole of the second permanent arrangement 40'. The magnetization portion 16b of the tip 16 is thus penetrated to a lesser extent by the magnetic field of the second permanent assembly 40 'than when the first permanent magnet assembly 32 is located farther from the magnetization portion 16b. The soft magnetic tip is then magnetized less strongly than when the permanent magnet assembly 32 is disposed further away from the soft magnetic tip 16, in particular at a maximum distance, as shown in Figure 2b.

Even with this alternative configuration, without changing the space requirement of the magnetic separation device 10, both a rotation of the soft magnetic tip 16 about the device axis V and a displacement movement of the permanent magnet arrangement 32 for the purpose of changing the magnetization State of the soft magnetic tip 16 possible by a single movement drive.

Claims

claims

A magnetic separation apparatus (10) for separating magnetic particles from a suspension (14) having a soft magnetic tip (16) extending along a tip axis (S) whose magnetization state is selectively changeable between a more magnetized state and a weaker magnetized state, wherein Tip (16) having an immersion end (16a) for insertion into the suspension (14) and a magnetization section (16b) for changing the magnetization state of the tip (16), the separation device (10) having a motion drive and one in motion communication therewith standing magnet arrangement (32) which comprises at least one permanent magnet or is formed from at least one permanent magnet and which by the movement drive to the magnetization section (16b) approachable and removable from, so that the magnetic field of the magnet assembly (32) in the magnetization section (16b ) of the tip (16) r is change in the magnetization state of the tip (16) over time, characterized in that the soft magnetic tip (16) about the tip axis (S) is rotatable.

Magnetic separation device (10) according to claim 1,

characterized in that the soft magnetic tip (16) is rotatable in its weaker magnetized state.

Magnetic separation device (10) according to claim 1 or 2,

characterized in that the movement drive is coupled in a motion-transmitting manner both with the magnet arrangement (32) in order to drive it towards its approach movement to the magnetization section (16) and away from it, and is also coupled in a motion-transmitting manner to the soft magnetic tip (16), to drive them for rotation about the tip axis (S). Magnetic Trennvor device (10) according to any one of the preceding claims,

characterized in that the magnet arrangement (32) is coupled in a motion-transmitting manner to the movement drive by means of a gear (24c, 30) from which a gear part (24c) is coupled in a motion-transmitting manner to the tip (16).

Magnetic separation device (10) according to claim 4,

characterized in that the transmission (24c, 30) is a screw drive (24c, 30).

Magnetic separation device (10) according to claim 5,

characterized in that the screw drive (24c, 30) has a threaded rod (24c) connected for common rotation with the soft-elastic tip (16) passing through the magnet assembly (32), the magnet assembly (32) being movable together with a threaded nut (32). 30) of the screw drive (24c, 30) is connected, preferably part of the threaded nut (30) of the screw drive (24c, 30).

Magnetic separation device (10) according to claim 6,

characterized in that the maximum distance of the magnet assembly (32) from the tip (16) is defined by a threaded end of the threaded rod (24c) with a rod intermediate portion (24d) between the threaded end and the moving drive, to which the magnet assembly (32 ) is disengaged from a threaded portion (24c) of the threaded rod (24c) and remains in the removal sense at substantially the same distance from the soft elastic tip (16) even with continued rotation of the threaded rod (24c).

Magnetic separation device (10) according to one of claims 5 to 7,

characterized in that the threaded rod (24c) extends along a rod axis (V) which is collinear with the tip axis (S). Magnetic Trennvor device (10) according to any one of the preceding claims,

characterized in that the maximum approximation of the magnet arrangement (32) to the tip (16) is formed by a stop (20) which is preferably also at least partially soft-elastic, to which the magnet arrangement (32) preferably in the more magnetized state of the tip (16). is applied.

0. Magnetic separation device (10) according to claim 9,

characterized in that when the magnet assembly (32) is prevented by abutment against the stop (20) on a further approach movement, the movement drive is locked for further operation in the approach sense or a force or torque-dependent coupling in force or Torque transmission between movement drive and magnet assembly (32) prevents further torque transmission in the proximity sense.

1 . Magnetic separation device (10) according to one of the preceding claims,

characterized in that the magnet arrangement (32) is at least partially, preferably completely, rotationally symmetrical.

2. Magnetic separation device (10) according to one of the preceding claims,

characterized in that it comprises a second magnet arrangement (40 ') permanently connected to the soft magnetic tip (16), the magnet arrangement (32) which can be approached to the tip (16) and be removed from the tip (16) condition closer to the magnetization portion (16b) weakens the magnetic field of the second magnet assembly (40 ') more than the condition further away from the tip (16).

13. Magnetic Trennvornchtung (10) according to claim 12,

characterized in that the second magnet assembly (40 ') passes through the approachable and removable magnet assembly (32).

14. A magnetic separation device (10) according to claim 12 or 13,

characterized in that the second magnet arrangement (40 ') with the tip axis (S) as rotation symmetry axis is at least partially rotationally symmetrical, wherein preferably the second magnet arrangement (40') is part of the threaded rod (24c).

A magnetic separation device (10) according to any one of claims 12 to 14, characterized in that the approximate and removable magnet assembly (32) and the second magnet assembly (40 ') are coaxially disposed in opposite polarization with their respective magnetic poles along the common axis of extent (Fig. V) follow one another.

16. Pipetting device with at least one magnetic separation device (10) according to one of claims 1 to 15 instead of a pipetting channel. 17. A liquid handling apparatus comprising a plurality of magnetic separation devices (10) according to claims 1 to 15, wherein the plurality of magnetic separation devices (10) are provided with grid-like parallel peaked axes (S), each separation device (10) having its own motion drive which is separate from the separate operated by the motion drives of the other separators.