WO2017046234A1 - Magnetic separating device with magnetic activation and deactivation - Google Patents

Abstract

The present invention relates to a magnetic separating device (10) for separating magnetic particles from a suspension (14) with a soft magnetic tip (16), the magnetization state of which can be selectively changed between a more strongly magnetized state and a more weakly magnetized state, the tip (16) having 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 magnet arrangement (22), the magnetic field of which can be varied over time in the magnetizing section (16b) of the tip (16) for changing its magnetization state, characterized in that the separating device (10) comprises a second magnet arrangement (30), the first magnet arrangement (22) and the second magnet arrangement (30) being displaceable relative to each another, and the magnetization state of the soft magnetic tip (16) being dependent on the relative position of the two magnet arrangements (22, 30).

Description

 Magnetic separation device with magnetic activation and

 deactivation

description

The present invention relates to a magnetic separator for separating magnetic particles from a suspension having a soft magnetic tip whose magnetization state is selectively changeable between a more magnetized state and a weaker magnetized state, the tip having a dip end for introduction into the suspension and a magnetization section for changing the magnetization state of the tip, wherein the separation device comprises a magnet arrangement whose magnetic field in the magnetization section of the tip is variable in time to change its magnetization state.

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 solely as a means of transport and are usually coated in such a way that only a certain constituent of the suspension can and will attach to the particle-facing outer surface of the coating, 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.

A generic magnetic separation device 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 to attract the magnetic particles contained in the suspension until it rests against an outer surface of the soft magnetic tip and then they can remove frictionally or force-locking 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 protective covering surrounding the insertion end of the soft magnetic tip.

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 through which the soft-magnetic tip is rotatable about its longitudinal axis.

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 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 arrangement. 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, especially when the electromagnet for Magnetization of 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 solenoid provides its magnetic field only with energization, it comes during operation of the magnetic separator to a heating of the electromagnet and thus at least the risk of thermal stress on the suspension to be processed, which may be disadvantageous especially for thermally sensitive ingredients of the suspension. Another magnetic separation device also having all the features of the preamble of claim 1 is known from US 4,751,053. This separator also uses an electromagnet coaxial with and axially overlapping the soft magnetic tip of the separator with respect to the longitudinal axis of the soft magnetic tip. However, the electric ring magnet of US Pat. No. 4,751,053 encloses the soft magnetic tip used there radially more narrowly than the known from WO 02/40173 A1 electric ring magnet, whereby the construction of the known from US 4,751,053 A separation device is radially less expansive as the previously discussed. However, the electric ring magnet, which changes the magnetization state of the soft-magnetic tip acting as armature or iron core solely by energizing and non-energizing, is also arranged comparatively close to the suspension to be processed, which in turn leads to the above-described risk of undesirable thermal effects Loading of the suspension by the separator is. Another magnetic separation device is known from US 7 776 221 B2. This document discloses a plurality of soft magnetic tips which protrude from an area defining an air gap between the free leg ends of a C-shaped magnetic yoke. On the opposite surface, which restricts the air gap of the magnetic yoke in the opposite direction, sample containers are provided, into which a suspension with magnetic particles can be added. The soft-magnetic tips of the separating device known from US Pat. No. 7,776,221 B2 are in their entirety direction to the suspension containers rotatable, but not lowered to the containers down.

One or more permanent magnet arrangements are movably received in a recess of the magnetic yoke, so that the magnetization state of the soft magnetic tips connected to the yoke can be changed by relative movement of these magnet arrangements relative to the yoke.

This separation device is extremely space-demanding, since the soft magnetic tips are taken in the direction of distance to the suspension containers non-depositing on Magnetjoch and the tips can be immersed only by displacement of the suspension container by means of an additional manipulation device in the suspension to be processed. Very similar magnetic separation devices are known from DE 10 2005 004 664 A1 and from US 5 567 326 A. The separation devices known in this way have a plate from which a plurality of soft-magnetic tips, which as a rule are arranged in the manner of a matrix, protrude parallel to one another in a downward direction. On the plate supporting the soft magnetic tips, a permanent magnet may be temporarily placed on the plate side facing away from the protruding tips to change the magnetization state of the soft magnetic tips in their entirety, that is, to magnetize all the soft magnetic tips when the permanent magnet is present, and to demagnetize if the permanent magnet is not present.

Another magnetic separation device is known from US 4 649 1 1 6 A. In this device, a soft magnetic tip and a non-magnetic, ie non-magnetized and non-magnetizable, collinear material in the axial direction with respect to the longitudinal axis of the soft magnetic tip are arranged one behind the other.

Laterally to this arrangement of soft magnetic tip and non-magnetic material in a direction a horseshoe magnet is attached, of which a free Leg end in an active position in which the magnetic separation device is biased by a spring and in which the soft magnetic tip is magnetized, the soft magnetic tip radially opposite - therefore their magnetization - and the other free leg end of the non-magnetic material is radially opposite.

Against the spring preload described above, the soft magnetic tip can now be moved along with the non-magnetic material past the two free leg ends of the horseshoe magnet until both leg ends of the horseshoe magnet lie opposite the non-magnetic material. At this moment, the soft magnetic tip loses its transient magnetization and is nonmagnetic, or at least less magnetised, since a certain leakage flux may not be ruled out. This separator is radially expansive due to the horseshoe magnet used.

From US Pat. No. 5,647,994 A, a magnetic separation device is known in which an annular permanent magnet arrangement surrounds a pipetting tip radially on the outside and can be displaced in the longitudinal direction of the pipetting tip in order to apply different magnetic fields to different areas of the pipetting tip.

A soft-magnetic tip can be lowered into the pipetting tip, so that a relative position of soft-magnetic tip and parallel permanent magnet arrangement can be achieved with the magnetic separation device known from US Pat. No. 5,647,994 A, in which the soft-magnetic tip penetrates the permanent magnet arrangement, thus the soft-magnetic one Axially overlap tip and the permanent magnet assembly in the longitudinal direction of the soft magnetic tip, so that the soft magnetic tip is more magnetized within the pipette tip than when the two components: soft magnetic tip and permanent magnet assembly, not axially overlap.

The present application is therefore based on the object to further develop the generic magnetic separation device such that it takes up less space and as little as possible loads the suspension to be processed. This object is achieved by a generic magnetic separation device in which one of the two magnet assemblies is stationary relative to the soft magnetic tip and the other magnet assembly is movable relative to the tip and a magnet assembly.

The inventively proposed solution, the first and the second magnet arrangement can be used to neutralize each other depending on the relative position by field closure, so that no or only a smaller magnetic field acts on the soft magnetic tip of them, or they just can not neutralize, so one of them or at least by one of the magnet arrangements emanating magnetic field acts on the soft magnetic tip and these stronger magnetized in contrast to the aforementioned condition. Due to the possibility of changing the magnetic field emanating from the two magnet arrangements and acting on the soft magnetic tip by relative arrangement of the two magnet arrangements, it is fundamentally possible to have a switchable magnetic separation device that can be changed with regard to the magnetization state of the soft magnetic tip, at least for the duration of the more magnetized state de-energized and thus provide substantially no heat sources.

Moreover, by variable relative arrangement of the two magnet assemblies, it is possible to change the magnetization state of the soft magnetic tip not only as in the prior art between a first state of low or no magnetization and a second state of stronger magnetization. Rather, the variable relative arrangement of the two magnet arrangements offers the possibility of selectively changing the degree of magnetization of the soft-magnetic tip even at intermediate values lying between two extreme values, preferably even to change them steplessly, at least in regions. This is possible, for example, if the relative positions of the two magnet arrangements are continuously variable relative to one another, at least in a region of the relative mobility of the two magnet arrangements. The first mentioned in the solution of the present invention underlying task magnet assembly is the initially mentioned magnet assembly.

By "magnetic" is meant a material which is either magnetizable or magnetised. In most applications of the presently discussed magnetic separation device, the magnetic particles will comprise ferromagnetic material or be made of ferromagnetic material.

In principle, it is possible that both magnet arrangements are arranged to be displaceable relative to the soft-magnetic tip, so that each of the first and the second magnet arrangement can be displaced relative to the soft-magnetic peak.

In order to minimize the number of guide and drive means required for the formation of the separating device according to the invention, it is preferably provided that one of the two magnet arrangements is stationary relative to the soft magnetic tip and the other magnet arrangement is movable relative to the tip and to a magnet arrangement.

According to a first preferred embodiment, in which, however, the magnetic field of a currentable electrical coil is used at times, comprises one of the two magnet assemblies as a magnetizing magnet assembly at least one permanent magnet and is displaceable between a further away from the tip and separated by an air gap of this not Magnetization position and a magnetization position more closely approximated to the tip, wherein the respective other magnet arrangement as a drive magnet arrangement has an optionally energizable electrical coil which, depending on its energization, displaces the magnetization magnet arrangement from the magnetization position to the non-magnetization position. In principle, it may be thought to displace the magnetization magnet assembly from the non-magnetization position to the magnetization position with further drive means. However, for reasons of the lowest possible number of components on the separating device, it is preferred if this displacement can likewise be effected by the drive magnet arrangement.

The magnetizing magnet arrangement is that magnet arrangement of the first and the second magnet arrangement whose magnetic field is "coupled" into the magnetically soft peak in the magnetization position of the magnetization magnet arrangement and thus effects a magnetization of the soft magnetic peak. In the non-magnetization position, the magnetization magnet assembly is located farther away from the soft magnetic tip than in the magnetization position such that in the non-magnetization position, the magnetic field from the magnetization magnet assembly is less strong than at the magnetization position or even at the soft magnetic tip acts. Then, when the magnetization magnet assembly is in its non-magnetization position, the soft magnetic tip is less magnetized than when the magnetization magnet assembly is in its magnetization position closer to the tip. Preferably, the soft magnetic tip is unmagnetized in the non-magnetization position of the magnetization magnet assembly.

The other of the two magnet arrangements, which is referred to as a drive magnet arrangement, is preferably used only for displacing the magnetization magnet arrangement between its stated positions: magnetization position and non-magnetization position. The displacement of the magnetization magnet arrangement between its stated positions is effected in dependence on the energization of the drive magnet arrangement.

Preferably, the magnetization magnet arrangement is a permanent magnet or a permanent magnet arrangement with a plurality of permanent magnets, around a currentless magnetized magnetization magnet arrangement and thus a currentless provide magnetizable tip. Therefore, the magnetization magnet arrangement preferably does not include an electromagnet.

Since the drive magnet arrangement must be energized only for a displacement of the magnetization magnet arrangement with a suitable structural design of the separation device, the drive magnet arrangement need not be energized as in the prior art for the entire duration in which the magnet In general, the magnetization magnetization is in the magnetization position or in general: in which the magnetically soft tip has a state of stronger magnetization. In fact, it is usually sufficient to energize the drive magnet assembly during the approach movement of the magnetization magnet assembly to the magnetization position only as long as the magnetization magnet assembly is in the approaching motion and / or has approached the magnetization position to approach its approaching motion continues even with de-energized drive magnetization arrangement until reaching the magnetization position.

The drive arrangement is preferably arranged in the separation device in such a way that its energization effects removal of the magnetization-magent arrangement from the soft-magnetic tip. The energization of the drive magnet assembly thus causes an adjustment of the magnetization magnet assembly in the non-magnetization position.

Then, when the magnetizing magnet assembly is arranged to be displaceable with a component in the direction of gravity action or completely in the direction of gravity, the displacement of the magnetization magnet assembly from the non-magnetization position to the magnetization position can be gravity driven or at least assisted by gravity. In this case, it may be sufficient to terminate the energization of the gravity compensating drive magnet assembly to shift the magnetization magnet assembly to the magnetization position and thus to increase the magnetization state of the soft magnetic tip from a less strong magnetization to a stronger magnetization change. In this case, even if the drive magnetization assembly had to remain energized in the non-magnetization position for the duration of the magnetization magnet assembly to keep the magnetization magnet assembly in the non-magnetization position, then in this operating state the immersion end would be the one less magnetized soft magnetic tip not immersed in the suspension to be processed, so that the risk of thermal stress on the suspension to be processed by the energized drive magnet arrangement due to the then possible spatial distance of the separator from the suspension to be processed negligible or excluded is.

Incidentally, since the driving magnet assembly is required only for displacement of the magnetizing magnet assembly and / or for holding the magnetizing magnet assembly in the non-magnetizing position, this may be weaker in comparison with the magnetizing electromagnets of the prior art Electromagnet can be used, which develops during its energization only a smaller amount of heat, as is the case in the prior art for those electromagnets, which are used to magnetize the soft magnetic tip. This also reduces the risk of thermal influence on the suspension to be processed.

The drive magnet arrangement may, as already mentioned above, preferably also be used to displace the magnetization magnet arrangement from the non-magnetization position into the magnetization position. If, for example, the magnetization magnet arrangement is moved along its horizontal path orthogonal to the direction of gravity action, in each case energizing the drive magnet arrangement with corresponding current flow direction can move the magnetization magnet arrangement into one or the other of the following positions: magnetization position and non-magnetization position, In this case, the drive magnet arrangement only needs to be energized for the short periods of time until the magnetization magnet arrangement reaches its respective desired position from magnetization position and non-magnet position. position has reached. This also applies to all other cases in which constructive and / or functional care is taken that the magnetization magnet arrangement remains in at least one of its positions from the magnetization position and non-magnetization position until it is replaced by the magnetic force of the drive magnet arrangement is shifted from the respective position to the other position from non-magnetization position and magnetization position.

In principle, it may be sufficient if an air gap between the magnetization magnet arrangement and the soft-magnetic tip, in particular its magnetization section, is smaller in the magnetization position than in the non-magnetization position of the magnetization magnet arrangement. However, a particularly advantageous high degree of magnetization of the soft-magnetic tip can be achieved in that the magnetization magnet arrangement is in magnetic contact with the magnetically soft tip in the magnetization position, ie it is either in direct physical contact with the magnetization section or indirectly with interposition of a ferromagnetic material Touch contact is with this, in which case preferably the magnetization magnet assembly is in physical contact with the intermediate ferromagnetic material and the ferromagnetic material is in contact with the magnetization portion of the soft magnetic tip. Advantageously, therefore, there is no air gap between the magnetization magnet arrangement and the soft magnetic tip, in particular its magnetization section, in the magnetization position. By contrast, in the non-magnetization position, such an air gap is preferably present between the soft magnetic tip, in particular its magnetization section, and the magnetization magnet arrangement.

Preferably, as already indicated above, the magnetic separation device has a holding device which holds the magnetization magnet arrangement in the non-magnetization position. In such a case, the necessary holding force for holding the magnetizing magnet assembly in the non-magnetic sierungsposition be applied by the holding device. It then does not need to be applied by energizing the drive magnet assembly.

In one exemplary embodiment, the holding device may, for example, be a frictional holding device whose frictional force is lower than the magnetic force exerted by the drive magnet arrangement when energized on the magnetization magnet arrangement. Such a frictional force can be achieved for example by clamping jaws whose clamping force is selectively adjustable by biasing means taking into account the clamped between them portion of the magnetizing magnet assembly, such as spring preload in the closing direction.

Preferably, however, the holding device has the holding device on a ferromagnetic holding part, with which the magnetizing magnet arrangement is in magnetic contact in the non-magnetizing position. Since the magnetization magnet arrangement already has a permanent magnet and is therefore permanently magnetized at least in sections, the magnetic field emanating from it can be used in a particularly simple manner to hold the magnetization magnet arrangement in the non-magnetization position. Again, it is important to ensure that the outgoing from the drive magnet assembly in the case of their energization magnetic field and the resulting force acting on the magnetization magnet assembly magnetic force is greater than the force exerted between the magnetization magnet arrangement and the ferromagnetic holding part of the holding device magnetic force is. However, this should be easily possible because the same condition must be met for releasing the magnetization magnet assembly from the magnetization portion of the soft magnetic tip from the magnetization position.

For example, the ferromagnetic holding part may be dimensioned such that it is in magnetic saturation when it is in the non-magnetization position in magnetic contact with the magnetizing magnet assembly. Preferably, the holding part may be made of soft magnetic material. For reasons of particularly simple design of the separator, it may be made of the same soft magnetic material as the soft magnetic tip. According to another preferred embodiment of the separation device according to the invention can be provided that one of the two magnet assemblies as magnetization magnet assembly comprises at least one permanent magnet, preferably a permanent magnet or a permanent magnet arrangement with multiple permanent magent is relative to the soft magnetic tip is non-displaceable and permanently with the soft magnetic tip in Magnetschlussschluss contact is, and that the other of the two magnet assemblies comprises a switching magnet assembly at least one permanent magnet and is displaceable between a switch-off, in which it weakens the magnetization magnetic field of the magnetization magnet assembly in the region of the magnetization section with its switching magnetic field, and a switch-on position in which, with its switching magnetic field, it sets the magnetization magnetic field of the magnetization magnet arrangement in the region of the magnetization section weakens less strongly. In contrast to the previously described embodiment in which the drive magnet assembly has been used to move the magnetization magnet assembly between two positions in which it magnetizes the soft magnetic tip to different degrees, the basic idea of the second embodiment now discussed is an arrangement in which the magnetization magnet arrangement, which provides for the magnetization of the soft-magnetic tip, is arranged to be non-displaceable relative thereto and in which the switching magnet arrangement is displaceable in order to vary its magnetic field depending on its relative position to the magnetization magnet arrangement to weaken or neutralize.

By using at least one permanent magnet in each of the magnetization and switching magnet arrangement magnet assemblies the power consumption of the magnetic separation device is significantly reduced, thus avoiding unwanted heat sources in the separator.

A simple possibility of weakening the magnetic field emanating from the magnetization magnet arrangement is to use the switching magnet arrangement in field closure for a magnetic return, for example when the switching magnet arrangement is in its switch-off position. Then, when unlike poles of the magnetization magnet arrangement on the one hand and the switching magnet arrangement are in close proximity in the switch-off position, the magnetic field emanating from one pole of the magnetization magnet arrangement can travel via the switching magnet arrangement in the direction of the other pole the magnetization magnet assembly are passed without the soft magnetic tip is penetrated to a considerable extent by the magnetic field of the magnetization magnet assembly.

Preferably, therefore, the switching magnet assembly is in its off position closer to that pole of the magnetization magnet assembly, which in turn is closer to the soft magnetic tip. Therefore, it may be advantageous if the magnetizing magnet arrangement and the switching magnet arrangement are oppositely polarized along their relative movement path. In that case, it is particularly easy to approach each other by merely translational, preferably rectilinear, movement of the switching magnet arrangement relative to the magnetization magnet arrangement, unlike poles of switching magnet arrangement and magnetization magnet arrangement in a region located close to the soft magnetic peak ,

The magnetization magnet arrangement is preferably shorter than the magnetization magnet arrangement along the relative movement path, which is preferably a rectilinear relative movement path. As a result, their relative mobility is facilitated relative to the magnetizing magnet arrangement along the relative movement path. Although in principle the switching magnet arrangement can move along its relative movement path over the extension length of the magnetization magnet arrangement in the direction of the relative movement path, it may in principle be sufficient if the relative movement path of the switching magnet arrangement does not extend beyond the extension component of the magnetization magnet arrangement along the Relative movement path extends. Thus, a short separation device along the relative movement path can be obtained.

Then it is possible to provide, for example, at the soft magnetic tip closer longitudinal end of the magnetization magnet assembly, a magnetic coupling device for coupling the soft magnetic tip in the magnetic field of the magnetization magnet assembly and preferably this coupling formation as an end stop for the relative movement of the switching magnet assembly to soft elastic tip to use.

Even in the on position of the switching magnet arrangement are preferably unlike poles of both magnet arrangements in close proximity to each other, but other poles than in the off position. The strong convergence of unlike poles of the two magnet assemblies together leads to a stable equilibrium situation, so that neither in the on position nor in the off position of the switching magnet assembly holding devices for holding the switching magnet assembly in at least one of the respective positions are required, although not excluded, the like Provide holding devices for reasons redundant reliability.

The switching magnet arrangement can also be designed in an extremely advantageous manner to be displaced due to magnetic forces between its two positions: switch-off position and switch-on position. For this purpose, it can be provided that the magnetic separation device has a third magnet arrangement which comprises at least one optionally energizable electrical coil and which as a trigger magnet arrangement depends on its current supply Displacement of the switching magnet assembly between their on and their off position causes.

Although a current source and thus a possible heat source is again introduced into the magnetic separation device with the trigger magnet arrangement, it may be sufficient to energize the trigger magnet arrangement only for a short time, so that it develops a magnetic field that is too short in time a force pulse leads, which releases the switching magnet assembly from its respective position and accelerates to each other position. Then, when in the two positions of the switching magnet arrangement: switch-on position and switch-off position, unlike poles of the two magnet arrangements: switching and magnetization magnet arrangement are sufficiently close to each other, the force pulse through the trigger magnet arrangement only has to prevail Overcome the state of equilibrium and remove the switching magnet arrangement sufficiently far from the respective position, so that the two other unlike poles of the two magnet arrangements assigned to the other position from switch-on position and switch-off position come so close to each other that the new equilibrium position of the respective other one Position by yourself.

The magnetic separation device is therefore preferably designed to energize the trigger magnet arrangement only during the transition of the switching magnet assembly from one of its positions: switch-on position and switch-off position, into the respective other position, wherein - as described above - energization for the entire duration the relative movement of switching magnet assembly and magnetization magnet arrangement is not absolutely necessary.

The trigger magnet assembly may advantageously effect, in both switch magnetization and switch off positions, a displacement relative to the magnetizing magnet assembly into the other position when the trigger magnet assembly is coupled for common movement with the switching magnet assembly. The trigger magnet arrangement may advantageously be arranged coaxially to the switching magnet arrangement, that is to say extending over a common region of the relative movement path. It can also be arranged collinear with the switching magnet arrangement, for example in the direction of the relative moving path to the switching magnet arrangement subsequently.

In order to be able to bring about their displacement into the respective other position particularly effectively in both positions of the switching magnet arrangement: switch-on and switch-off position, the trigger magnet arrangement can have at least two coaxial winding sections between which the switching magnet arrangement is arranged.

Alternatively, the trigger magnet arrangement can also be arranged along the relative movement path of switching magnet arrangement and magnetization magnet arrangement between two permanent magnets of the switching magnet arrangement.

It is advantageous if the switching magnet arrangement and the trigger magnet arrangement, both individually and jointly considered, each generate a symmetrical magnetic field which is oriented orthogonal to the relative movement path of the switching magnet arrangement. However, this is not necessary for the function.

The switching magnet arrangement can be formed from a plurality of permanent magnets stacked along the relative movement path in order to generate a particularly strong magnetic field and / or to simplify the repairability of the switching magnet arrangement.

A possible objective of the present magnetic separation device is to use a plurality of soft magnetic tips simultaneously, wherein preferably the plurality of soft magnetic tips are provided in a predetermined arrangement pattern, for example arranged in rows and columns.

In order for such a matrix-like arrangement of soft magnetic tips of a magnetic separation device, the magnetic separation device as possible To be able to provide little radial space, it is advantageous if the soft magnetic tip extends along a tip axis. The assembly of the soft magnetic tip in the magnetic separation device can be simplified if the soft magnetic tip is at least partially, preferably completely, rotationally symmetrical with respect to the tip axis formed as rotational symmetry axis.

It also serves the radially slender construction of the magnetic separation device, when the relative displacement path of the two magnet assemblies is parallel or preferably collinear with the tip axis. "Parallel" means that there is a gap between the lines running in the same direction: tip axis and relative displacement track. This is 0 in collinear order.

A magnetic field of the two magnet arrangements which is as homogeneous as possible for the two abovementioned embodiments as well as for the very very general solution of the object underlying the present invention can be obtained by virtue of the fact that one magnet arrangement is the other surrounds, in which case a particularly advantageous homogeneous and symmetrical magnetic field of the magnetic separation device can be obtained in total, if the one magnet arrangement surrounds the other coaxially. For the reasons mentioned, a complete enclosure of one magnet arrangement by the other is preferred.

Thus, in the first embodiment mentioned above, it is preferable for the drive magnet assembly to surround the magnetization magnet assembly. In the second mentioned preferred embodiment, it is preferable if the switching magnet arrangement, optionally together with the trigger magnet arrangement, surrounds the magnetization magnet arrangement. Thus, the above-mentioned magnetization magnet arrangement preferably also extends along a magnet arrangement axis, which is preferably arranged collinear with the tip axis. Even if a magnet arrangement surrounding the respective other magnet arrangement extends along an extension axis, the extension axis then only passing through a cavity surrounded by the magnets of the magnet arrangement, it is advantageous if this extension axis and the tip axis are arranged collinear.

Preferably, therefore, both magnet arrangements, that is to say magnetization magnet arrangement on the one hand and drive or switching magnet arrangement on the other hand, and the soft magnetic peak are arranged coaxially with collinear course axes.

It is therefore preferably provided that at least one part of the permanent magnets of at least one, preferably both magnet arrangements, is coaxial with the tip axis and is polarized along this axis and is preferably rotationally symmetrical with respect to the tip axis as rotational symmetry axis. This is particularly preferred for all permanent magnets of at least one, preferably both magnet arrangements, which are for the above-mentioned particular embodiments, at least the magnetizing magnet arrangement on the one hand and the drive or switching magnetization arrangement on the other hand. Preferably, the soft magnetic tip is rotatable to improve the separation of magnetic particles of suspension liquid, wherein the axis of rotation of the soft magnetic tip is preferably its tip axis. For this reason, it is also preferred that the magnetic separation device has a rotary drive, which is coupled with the soft-magnetic tip to transmit motion and torque. By this rotary drive, the tip is rotatable.

A rotary drive component, for example a shaft or hub stub permanently coupled to the soft-magnetic tip for common rotation about the axis of rotation and releasably coupled or coupled to the rotary drive, may be formed at least partially from soft magnetic material, the rotary drive component then acting as the above-mentioned holding device can hold the magnetization magnet assembly in the non-magnetization position. To achieve a desired slim design, the two magnet arrangements, preferably also the above-mentioned release magnet arrangement, are preferably arranged in the direction of the tip axis between the soft-magnetic tip and the rotary drive, in particular between the tip and the aforementioned rotary drive component. This preferably applies regardless of the respectively assumed position of the movable magnet arrangement.

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 simultaneously process different suspensions with such a separator head, preferably the magnetization state of at least part of the soft magnetic tips of the separator head is changeable independently of another part of the soft magnetic tips. This independent changeability of the magnetization state of soft magnetic tips in a separator head can be done by individually energizing the magnet arrangement effecting the change of the magnetization state of the respective soft magnetic tip. Preferably, the magnetization state of each individual soft magnetic tip of the separator head is changeable independently of the magnetization state of each other soft magnetic tip.

Since the change in the state of magnetization by means of energization of a magnetic arrangement takes place, the energization of individual magnet arrangements can be effected in a simple and reliable manner by a corresponding control device, wherein the control device can also be designed to soft magnetic peaks of the separation device head lines or / and columns to common- seed change of the magnetization state. In this case, the control device can change all the soft magnetic peaks of a row or / and a column by common control of the respective magnet arrangements in the same sense and simultaneously.

Such magnetic separation devices can be advantageously 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, a separator formed as described above has 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 magnet arrangements which are described as being movable relative to the soft-magnetic tip in the present application can be guided to move them on a carrier component which is at least not translationally displaceable relative to the soft-magnetic tip. Preferably, the support member is located between the soft magnetic tip and the rotary drive. The carrier component can pass through a magnetic arrangement guided on it for relative movement with a guide section or surround it radially on the outside.

The present invention will be explained in more detail with reference to the accompanying drawings. It shows:

FIG. 1 a is an elevational view of a first embodiment of a magnetic separation device according to the invention of the present application with a Magnetization magnet assembly and a drive magnet assembly, wherein the magnetization magnet assembly is in its non-magnetization position, Figure 1 b is a longitudinal sectional view through the apparatus of Figure 1 a along the

 Section plane Ib-Ib in Figure 1 a,

FIG. 2a shows the first embodiment of the magnetic separation device according to the invention from FIG. 1a, but with the magnetization magnet arrangement in the magnetization position,

FIG. 2b shows a longitudinal sectional view of the device of FIG. 2a along the sectional plane IIb-IIb in FIG. 2a, FIG. 3a shows a second embodiment of a magnetic according to the invention

 Separating device with a magnetizing magnet arrangement and a switching magnet arrangement, the latter in the switch-on position,

Figure 3b is a longitudinal sectional view through the magnetic separator of FIG

 3a along the sectional plane ll lb-lllb in Figure 3a,

FIG. 4a shows the magnetic separating device of FIG. 3a, but with the switching magnet arrangement in the switched-off position, and FIG. 4b shows a longitudinal sectional view through the device of FIG

 Section plane IVb-IVb in Figure 4a.

In FIGS. 1 a to 2 b, a first embodiment of a magnetic separation device according to the invention is designated generally by 10. Below the magnetic separation device is a sample vessel 12 shown by way of example, in which, as shown in FIG. 1 b, there is a suspension 14 with magnetic particles. The magnetic separator 10 extends along a device axis V, which is also included in the cutting plane Ib-Ib. The device axis V runs parallel to the drawing plane of Figure 1, the cutting plane Ib-Ib orthogonal to this. The magnetic separation device 10 has a soft-magnetic tip 16, which, as in the example shown, may be formed as a cylindrical component, wherein the cylinder axis or generally the longitudinal axis L of the soft-elastic tip 16 coincides with the device axis V. The soft-magnetic tip 16 has a dip end 16a closer to the container 12 and has a magnetization section 16b, which in the present example, as will be explained in more detail below, is structurally conditioned by the insertion end 16a opposite longitudinal end is formed. The soft magnetic tip 1 6 may be surrounded at its dip end 1 6a of a removable cover 18, through which the material of the tip 1 6 can be shielded from the suspension 14, in which the immersion end 1 6a of the tip 1 6 by movement is dipped along the device axis V operational and intended. The change sheath 18 is a detachable and replaceable provided at the top 16 protective cover.

The soft magnetic tip 1 6 is clamped with its magnetization section 1 6b in a socket portion 20a of a support member 20, for example, shrunk or screwed, glued, soldered and the like.

In the support member 20, which is preferably formed as the soft elastic tip 1 6 and rotationally symmetrical with respect to the device axis V, a first magnet assembly 22 as a magnetizing magnet assembly 22 along the device axis V is movably received. For this purpose, the carrier component 20 has a cavity 24, which is designed to be longer axially than the magnetization magnet arrangement 22 and in which the magnetization magnet arrangement 22 is axially movable relative to the device axis V. The support member 20 is preferably formed of non-magnetizable material, it may be formed of plastic, aluminum, brass and the like.

Axially in the direction away from the tip 16, a shaft stump 26 adjoins the carrier component 20, which in the illustrated example axially closes off the recess 24 in the carrier component 20.

The stub shaft 26 has a recess 28 for receiving a key, not shown in Figures 1 and 2, by means of which torque from a hub, also not shown on the stub shaft 26 is transferable to the stub shaft 26 and with this the device 10 in total for rotation to drive the device axis V as a rotation axis. By rotation of the stub shaft 26 and with this the device 10 in total, the non-rotatably coupled to the stub shaft 26 soft magnetic tip 1 6 are set in rotation about its longitudinal axis L, whereby in the radial direction relative to the device axis V acting centrifugal forces on possibly at the immersion -End 1 6a of the soft magnetic tip can be applied adhering magnetic particles 1 either to separate this still adhering suspension liquid of these, or to facilitate the separation of the magnetic particles from the immersion end 1 6a of the soft magnetic tip 1 6.

The rotary drive for the magnetic separator 10 is not shown in Figures 1 to 4. The stub shaft 26 has soft magnetic material at least at its longitudinal end 26a closer to the carrier component 22, so that the magnetization magnet device 22 physically abuts against the soft magnetic material of the longitudinal end 26a of the stub shaft 26 in the non-magnetization position shown in FIG. 1b with this manufactures. As a result of the magnetic forces thus formed between at least the longitudinal end 26a of the stub shaft 26 and the magnetization magnet arrangement 22, this remains in the illustrated non-magnetization position without external force. To adjust the magnetization magnet arrangement 22 into its magnetization position shown in FIG. 2b and back, a drive magnet arrangement 30 is provided radially on the outside of the carrier component 20, which surrounds a section of the carrier component 20 radially on the outside. Thus, the drive magnet assembly 30 also surrounds the magnetization magnet assembly 22 radially outward.

While the magnetization magnet arrangement is preferably formed from one or more permanent magnets, the magnetization magnet arrangement is preferably magnetized along the device axis V, so that, for example, its end facing the tip 16 has a magnetic south pole and its stub shaft 26 facing opposite longitudinal end 22b has a magnetic north pole, the drive magnet assembly 30 is preferably formed by an electromagnet, that is, by a bestrombare coil. The coil axis S preferably also coincides with the device axis V as an axis of symmetry M of the magnetization magnet arrangement 22.

By a short-term Bestromungsimpuls a magnetic field can temporarily be generated in the drive magnet assembly 30 which applies a magnitude larger and oppositely directed force to the Magneti- sierungs magnet assembly 22 with a suitable polarity than the magnetic closure between the longitudinal end 22b and acting as a holding device longitudinal end As a result, the magnetization magnet arrangement is thereby displaced into the magnetization position shown in FIG. 2b while shortening the axial distance between the longitudinal end 22a of the magnetization magnet arrangement 22 and the magnetization section 16b of the soft-magnetic tip 16 ,

In the magnetization position shown in FIG. 2b, the longitudinal end 22a of the magnetization magnet arrangement 22 preferably physically contacts the magnetization section 16b of the soft magnetic tip 16 and forms a magnetic circuit therewith, whereby the soft magnetic peak 16 is itself magnetized for the duration of this magnet closure , Then, when the soft magnetic tip 16 is magnetized, the magnetic particles in the suspension 14 deposit at the dip end 16a of the tip 16 as it is immersed in the suspension 14. As a result, the magnetic particles and with them adhering to their outside substances from the suspension 14 can be removed.

Due to the magnetic closure between the magnetization magnet arrangement 22 and the soft magnetic tip 16, magnetic forces act between the tip 16 and the magnetization magnet arrangement 22 and keep the magnetization magnet arrangement 22 in the magnetization position.

The displacement of the magnetization magnet arrangement 22 into the magnetization position of FIG. 2b and the whereabouts thereof are assisted by gravity in the arrangement shown here by way of example.

For the duration of the magnetic closure between the magnetization magnet arrangement 22 and the tip 16, the drive magnet arrangement 30 need not be energized. This must be energized only for the duration of solving the magnetization magnet assembly 22 of the longitudinal end 26a of the stub shaft 26 until the sum of gravity and attraction between the longitudinal end 22a and the tip 16 is greater than the attraction force between the opposite longitudinal end 22b and the longitudinal end 26a of the stub shaft. From this condition, the further displacement of the magnetization magnet arrangement 22 into the magnetization position is carried out automatically.

Thus, the only briefly energized drive magnet assembly 30 is not a significant heat source in the operation of the magnetic separation device 10.

In the example shown, since the magnetizing magnet assembly 22 must be displaced from the magnetizing position to the non-magnetizing position against the action of gravity, it may be necessary to energize the driving magnet assembly for shifting the magnetizing magnet assembly 22 to the non-magnetizing position for a longer time as a shift to the opposite set direction. However, this also does not contribute significantly to the heat development, since the energization in any case need not be continued beyond the duration of the shift out. After reaching the longitudinal end 26a of the stub shaft 26 and after making a magnetic circuit with this, the magnetizing magnet device 22 remains again in the non-magnetization position.

In this non-magnetization position, the soft magnetic material of the tip 16 is essentially not magnetized, so that when the immersion end 16a is immersed in the suspension 14 no magnetic particles are deposited on it.

FIGS. 3a to 4b show a second embodiment of the present invention. This second embodiment will be described below only insofar as it differs from the previously described first embodiment of Figures 1 a to 2b, the description of which is otherwise expressly referred to the description of the second embodiment.

In order to apply the above-described description to the second embodiment as well, the same components and component portions as in the first embodiment are given the same reference numerals in the second embodiment, but increased by 100 to distinguish.

Significant difference of the second embodiment of Figures 3 and 4 to the first embodiment of Figures 1 and 2 is that the magnetization magnet assembly 122 is disposed relative to the soft magnetic tip 1 16 non-displaceable. With its pointing away from the top of 1 1 6 longitudinal end 122 b, the magnetization magnet assembly 122 is in permanent contact with the longitudinal end 126 a of the stub shaft 126. Since in the present case on magnetic holding forces between the stub shaft 126 and the magnetization magnet assembly 122 does not matter , the stub shaft 126 may be made of any material in the second embodiment. The longitudinal end 126a does not need to be soft magnetic. With its longitudinal end 122a facing tip 1 1 6, the magnetization magnet arrangement 122 is permanently magnetically in contact with the magnetization section 16b of the tip 1 1 6, this magnet closure being produced indirectly in the present example via intermediate arrangement of a soft magnetic intermediate component 134 , which is in physical contact with the magnetic magnetization arrangement 122 at one end and with the soft magnetic tip 1 1 6 at the other end, in particular with its magnetization section 11b.

The soft magnetic tip 1 1 6 may be additionally coupled by a ring coupling 136 with the intermediate member 134. Also, the ring coupling 136 may be formed of soft magnetic material.

With the presently described arrangement, the soft magnetic tip 1 16 of the second embodiment can be interchangeable provided on the device 1 10.

The intermediate component 134 is preferably designed and arranged rotationally symmetrical with respect to the device axis V. In the configuration shown in FIG. 1, the soft-magnetic tip 1 1 6 is magnetized, so that in this state it is prepared to remove magnetic particles from the suspension 14.

The magnetization state of the tip 16 is controlled in the second embodiment by a switching magnet arrangement 130 which is displaceable relative to the magnetization magnet arrangement 122. In the illustrated example, the switching magnet assembly 130 along the device axis V is displaced. It is located in FIG. 3 in its switching-on position, which is farther from the tip 1 1 6, in which the magnetization magnet arrangement 122 is, as it were, "turned on", so that it causes a magnetization of the tip 1 1 6.

The switching magnet arrangement 130 is arranged coaxially with the magnetization magnet arrangement 122 such that its magnet arrangement longitudinal axis is aligned with the device axis V coincides. The same applies to the axis M of the magnetization magnet arrangement 122.

The switch magnet assembly 130 has one or more permanent magnets polarized along the device axis V, the polarization being opposite that of the magnetization magnet assembly 122.

Thus, the switching magnet assembly 130 forms at its tip 1 1 6 closer longitudinal end of a magnetic pole, which is unlike that of the longitudinal end 122 a of the magnetizing magnet assembly 122. For the opposite magnetic pole at the longitudinal end 130b, with respect to the magnetic pole at the longitudinal end 122b of the magnetizing magnet assembly 122, the same applies. As a result, the switch-on position of the switch magnet arrangement 130 relative to the magnetization magnet arrangement 122 illustrated in FIG. 3 is a stable state.

In order to change the magnetization state of the soft magnetic tip 1 1 6 and to shift the switching magnet assembly 130 from the switch-on position shown in Figure 3 in the off position shown in Figure 4, a further magnet assembly 132 is provided, which in the example shown, the switching magnet assembly 130th surrounds radially outside. This arrangement is not mandatory. The further magnet arrangement 132, which acts as a triggering magnet arrangement 132 in the sense of the introduction of the description, can also be arranged axially next to the switching magnet arrangement 130 or can be formed in a plurality of preferably coaxial sections and surround the switching magnet arrangement 130 between its sections.

The arrangement shown in the present example allows realization of an axially particularly short component of switching and tripping magnet arrangement. By brief energization of the trigger magnet assembly 132, a magnetic force can be exerted on the switching magnet assembly 130, so that these - again supported by gravity - is displaced into the position shown in Figure 4. This is the off position. Since in the switch-off position, the longitudinal ends 122b and 130b of the two magnet assemblies 122 and 130 are approximately at the same axial height and there are unlike poles formed on the different magnet assemblies 122 and 130, also the switch-off position shown in Figure 4 is a stable position.

Again, the trigger magnet arrangement 132, which forms a potential source of heat as an electromagnet, must be energized only briefly, wherein the duration of the acceleration due to the gravity support in the shift from the on position to the off position may be shorter than vice versa and the energization time due to the stability both positions: switch-on position and switch-off, the duration of the displacement movement of the switching magnet assembly 130 must not exceed time. Due to the short-term nature of the energization of the triggering magnet arrangement 132, its effect as a heat source is negligible.

Both embodiments shown allow a radially extremely slim design, which allows the integration of the magnetic separation device shown in a pipetting, in particular in a pipetting head, wherein the magnetic separation device can then replace a pipetting in the pipetting.

The radial dimension of the predominantly-with the exception of fewer component sections-rotationally symmetrical with respect to the device axis V formed magnetic separation device is preferably less than 20 mm in diameter, more preferably less than 18 mm in diameter.

Claims

 claims Magnetic separation device (10, 1 10) for separating magnetic particles from a suspension (14; 1 14) with a soft magnetic tip (1 6, 1 1 6), the magnetization state selectively changeable between a more magnetized state and a weaker magnetized state is, wherein the tip (1 6; 1 1 6) an immersion end (1 6a; 1 1 6a) for introduction into the suspension (14; 1 14) and a magnetization section (1 6b; 1 1 6b) to change the Wherein the separating device (10; 1 10) has a magnet arrangement (22; 122) whose magnetic field in the magnetization section (1 6b; 1 1 6b) of the tip (1 6; 6) is variable in time to change its state of magnetization, characterized in that the separating device (10; 10) comprises a second magnet arrangement (30; 130), the first (22; 122) and the second magnet arrangement (30; are mutually displaceable and the magnetizer State of the soft magnetic tip (16; 1 1 6) is dependent on the relative position of the two magnet arrangements (22, 30, 122, 130). A magnetic separation device (10; 110) according to claim 1, characterized in that one (30; 122) of the two magnet arrangements (22, 30; 122, 130) is stationary relative to the soft magnetic tip (1 6; 1 1 6) and the other magnet arrangement (22; 130) relative to the tip (1 6; 1 1 6) and to a magnet assembly (30; 122) is movable. Magnetic separation device (10) according to claim 2, characterized in that one of the two magnet arrangements (22) comprises at least one permanent magnet as the magnetization magnet arrangement (22), preferably at least one permanent magnet or a permanent magnet arrangement with a plurality of permanent magents, and is displaceable between a further away from the tip (1 6) and by an air gap of this separate non-magnetization position and a magnetization position closer to the tip (1 6), wherein the respective other magnet arrangement (30) serves as drive magnet arrangement (30) has an optionally energizable electrical coil which, depending on their energization, displaces the magnetization magnet arrangement (22) from the magnetization position to the non-magnetization position, preferably also vice versa. Magnetic separation device (10) according to claim 3, characterized in that the magnetization magnet arrangement (22) is in the magnetization position with the tip (1 6) in magnetic contact. Magnetic separation device (10) according to one of claims 3 or 4, characterized in that it comprises a holding device (26a) which holds the magnetization magnet arrangement (22) in the non-magnetization position. Magnetic separation device (10) according to claim 5, characterized in that the holding device (26a) has a ferromagnetic, preferably soft magnetic holding part (26a) with which the magnetizing magnet arrangement (22) is in magnetic contact in the non-magnetizing position. Magnetic separation device (1 10) according to claim 2, characterized in that one (122) of the two magnet arrangements (122, 130) as magnetization magnet arrangement (122) comprises at least one permanent magnet, preferably a permanent magnet or a permanent magnet arrangement with a plurality of permanent magnets, relative to the soft magnetic tip (1 1 6) is non-displaceable and permanently with the soft magnetic tip (1 1 6) is in magnetic contact, and that the other (130) of the two magnet assemblies (122, 130) as a switching magnet assembly (130) comprises at least one permanent magnet and is displaceable between an off position, in which it uses its switching magnetic field, the magnetization magnetic field of the magnetization magnet assembly (122) in the region of the magnetization section (1 1 6b) weaker, and a switch-on, in which it weakens the magnetization magnetic field of the magnetization Magnetan- order (122) in the region of the magnetization section (1 1 6b) with their switching magnetic field less. 8. Magnetic separation device (1 10) according to claim 7,  characterized in that the magnetizing magnet assembly (122) and the switching magnet assembly (130) are oppositely polarized along their relative movement path (V). 9. Magnetic separation device (1 10) according to claim 7 or 8,  characterized in that it comprises a third magnet arrangement (132) which comprises at least one optionally energizable electric coil and which as a trigger magnet assembly (132) depending on their energization, a displacement of the switching magnet assembly (130) between its on and off position causes. 10. Magnetic separation device (1 10) according to claim 9,  characterized in that the trigger magnet assembly (132) is coupled for common movement with the switching magnet assembly (130). 1 1. Magnetic separation device (10) according to claim 10,  characterized in that the trigger magnet assembly (132) is coaxial with the switch magnet assembly (130). 12. Magnetic separation device (10) according to claim 1 1,  characterized in that the trigger magnet assembly (132) comprises at least two coaxial winding sections between which the switching magnet assembly (130) is disposed. 13. Magnetic separation device (10, 1 10) according to one of the preceding claims, characterized in that the soft magnetic tip (1 6, 1 1 6) along a tip axis (L) extends, preferably at least partially rotationally symmetrical with respect to the tip axis (L) as rotational symmetry axis (M) is formed, wherein a Relativverlagerungsbahn (V) of the two Magnetic arrangements (22, 30, 122, 130) parallel, preferably collinear with the tip axis (L). Magnetic separation device (10; 1 10) according to one of the preceding claims,  characterized in that one magnet arrangement (30; 130) surrounds the other (22; 122), preferably coaxially surrounds. Magnetic separation device (10; 1 10) according to one of the preceding claims, including claim 13 and one of claims 3 or 7,  characterized in that at least a portion of the permanent magnets of at least one, preferably both magnet assemblies (22, 30; 122, 130) is coaxial with the tip axis (L) and is polarized along that axis (L) and preferably with respect to the tip axis (L) as a rotational symmetry axis (M) is rotationally symmetrical. Magnetic separation device (10; 1 10) according to one of the preceding claims,  characterized in that the soft magnetic tip (1 6; 1 1 6) extends along a tip axis (L), the separator (10; 1 10) having a rotary drive through which the tip (16; Tip axis (L) is rotatable. Pipetting device comprising at least one magnetic separation device (10; 110) according to one of claims 1 to 16 in place of a pipetting channel. 18. A liquid handling apparatus comprising a plurality of magnetic separation devices (10; 1 10) according to claim 16, wherein the plurality of magnetic separation devices (10; 1 10) with grid-like arranged parallel tip axes (L) is provided, each separation device (10; 1 10) has its own rotary drive for rotation of the respective tip (16; 1 1 6) about its tip axis (L) which can be operated separately from the rotary drives of the other separating devices (10;