Magnetic isolating apparatus with non-physical coupling between a magnet arrangement and the movement drive of said magnet arrangement

Abstract

A magnetic isolating apparatus (10) for isolating magnetic particles (66) from a suspension has an immersion section (30) which is designed to be temporarily immersed in the suspension, a guide apparatus (16) which extends along a guide path (F), a magnet arrangement (18) which is guided by the guide apparatus (16) such that it can be moved between an active position which is situated close to the immersion section (30) and an inactive position which is positioned further away from the immersion section (30) along the guide path (F), so that a magnetic field in the region of the immersion section (30) can be changed by moving the magnet arrangement (18) between the active position and the inactive position, and a drive apparatus (22, 50) by which the magnet arrangement (18) can be driven to move at least in a direction between the active position and the inactive position, wherein the drive apparatus (22, 50) is coupled in a non-physical manner to the magnet arrangement (18) by a force field and/or a fluid so as to transmit drive force.

Claims

1. A magnetic isolating apparatus for isolating magnetic particles from a suspension, the isolating apparatus comprising: an immersion portion that is embodied for immersion into the suspension; a guidance apparatus extending along a guidance path; a magnet arrangement that is guided by the guidance apparatus shiftably between an active position located closer to the immersion portion and an inactive position located along the guidance path farther from the immersion portion, so that a magnetic field in the region of the immersion portion is modifiable by shifting the magnet arrangement between the active position and the inactive position; a drive apparatus by means of which the magnet arrangement is drivable to move at least in a direction between the active position and the inactive position; and a sheath that surrounds the magnet arrangement orthogonally to the guidance path radially externally at least in the active position, and along the guidance path on the side facing away from the inactive position; wherein the drive apparatus is non-physically drive-force-transferringly coupled to the magnet arrangement by way of a fluid; wherein the magnetic isolating apparatus further comprises a coupling arrangement that is coupled at a first coupling point, constituting a guidance coupling point, to the guidance apparatus, and is embodied at a second coupling point, different from the first coupling point and constituting an apparatus coupling point, for detachable coupling to a pipetting channel of a pipetting apparatus; wherein the guidance apparatus comprises a guidance tube that guides the magnet arrangement for shifting between the active position and inactive position; wherein the guidance tube surrounds the magnet arrangement radially externally with reference to a tube axis coincident with the guidance path; wherein the magnet arrangement comprises a sealing arrangement that seals against the inner wall of the guidance tube and divides the volume enclosed by the guidance tube into an actuation volume closer to the inactive position and a displacement volume closer to the active position; wherein the sheath radially externally surrounds the guidance tube, and a gas-conveying conduit that terminates in the displacement volume of the guidance tube is embodied radially between the guidance tube and the sheath; wherein a longitudinal end of the sheath located closer to the inactive position is secured, detachably, on at least one of the guidance apparatus and the coupling arrangement; wherein the guidance tube comprises, at its longitudinal end located closer to the active position, openings passing radially through the guidance tube; and wherein the openings connect the displacement volume with the gas-conveying conduit formed between the sheath and the guidance tube.

2. The magnetic isolating apparatus according to claim 1, wherein a longitudinal end of the sheath located closer to the active position of the magnet arrangement, constituting an immersion longitudinal end, forms the immersion portion of the isolation apparatus.

3. The magnetic isolating apparatus according to claim 1, wherein a longitudinal end of the sheath located closer to the inactive position is secured on at least one of the guidance apparatus and the coupling arrangement; further comprising a sheath that surrounds the magnet arrangement orthogonally to the guidance path radially externally at least in the active position, and along the guidance path on the side facing away from the inactive position.

4. The magnetic isolating apparatus according to claim 1, further comprising a piston, connected to the magnet arrangement for motion together, which carries the sealing arrangement, the magnet arrangement being connected to the piston on a side thereof facing toward the displacement volume or at a region thereof located in the displacement volume.

5. The magnetic isolating apparatus according to claim 4, wherein a piston rod that connects the piston and the magnet arrangement for motion together is arranged between the piston and the magnet arrangement.

6. The magnetic isolating apparatus according to claim 5, wherein the guidance apparatus directly guides the piston and the piston rod to move along the guidance path.

7. The magnetic isolating apparatus according to claim 4, wherein the guidance apparatus comprises a guidance tube, the magnet arrangement being located, in any operating position, axially outside the guidance tube with reference to the tube axis of the guidance tube.

8. The magnetic isolating apparatus according to claim 1, wherein the coupling arrangement comprises a connecting conduit that fluid- and pressure-transferringly connects the apparatus coupling point to an actuation volume.

9. The magnetic isolating apparatus according to claim 1, wherein a holding apparatus comprising a holding magnet or a soft-magnetic holding component, which holds the magnet apparatus in the inactive position, is provided in the region of the inactive position.

10. The magnetic isolating apparatus according to claim 1, further comprising a control magnet arrangement whose magnetic field in the region of the guidance path is modifiable.

11. The magnetic isolating apparatus according to claim 10, wherein the control magnet arrangement encompasses a switchable electromagnet.

12. The magnetic isolating apparatus according to claim 10, further comprising a base body that is coupled to the guidance apparatus.

13. The magnetic isolating apparatus according to claim 12, wherein the control magnet arrangement is provided on the base body.

14. The magnetic isolating apparatus according to claim 12, wherein the base body includes a coupling arrangement that is coupled at a first coupling point, constituting a guidance coupling point, to the guidance apparatus, and is embodied at a second coupling point, different from the first coupling point and constituting an apparatus coupling point, for detachable coupling to a pipetting channel of a pipetting apparatus.

15. The magnetic isolating apparatus according to claim 10, further comprising at least one of a container embodied for reception of the suspension and a container carrier embodied for reception of the container, the control magnet arrangement being provided on the at least one of the container and on the container carrier.

16. The magnetic isolating apparatus according to claim 15, further comprising the container carrier that comprises a receiving recess for reception of a container portion, the control magnet arrangement being provided at at least one location of on the container carrier so as to surround the receiving recess, and below a placement surface on which the container, received on the container carrier, stands as intended on the container carrier.

17. The magnetic isolating apparatus according to claim 1, wherein the drive apparatus encompasses a pipetting apparatus.

18. The magnetic isolating apparatus according to claim 1 wherein a longitudinal end of the sheath located closer to the inactive position is secured, detachably, on at least one of the guidance apparatus and the coupling arrangement; further comprising a sheath that surrounds the magnet arrangement orthogonally to the guidance path radially externally at least in the active position, and along the guidance path on the side facing away from the inactive position.

19. The magnetic isolating apparatus according to claim 1, wherein the gas-conveying conduit is embodied radially between the coupling arrangement and the sheath.

Description

(1) The present invention will be explained in further detail below with reference to the attached drawings, in which:

(2) FIG. 1 is a longitudinal section view through a first embodiment according to the present invention of a magnetic isolating apparatus of the present invention, having the magnet arrangement in the inactive position and having an immersion portion of the isolating apparatus not yet immersed into a suspension that is furnished;

(3) FIG. 2 shows the first embodiment of FIG. 1 with the magnet arrangement shifted into the active position;

(4) FIG. 3 shows the first embodiment of FIG. 2 with the immersion portion immersed into the suspension;

(5) FIG. 4 is an enlarged depiction of the isolating apparatus of FIG. 3 but without a pipetting apparatus;

(6) FIG. 5 shows the first embodiment of FIG. 3 with magnetic solid particles of the suspension adhering to the immersion portion;

(7) FIG. 6 shows the embodiment of FIG. 5 retracted out of the suspension and out of the container receiving it;

(8) FIG. 7 shows the first embodiment of FIG. 6 lowered into an unloading vessel, with the magnet arrangement in the active position in order to unload the solid particles previously magnetically withdrawn from the suspension;

(9) FIG. 8 is a longitudinal section, corresponding to the depiction of FIG. 4, of a second embodiment of the present invention not having a pipetting apparatus as a drive apparatus; and

(10) FIG. 9 shows the isolating apparatus of FIG. 8 having no pipetting apparatus and no container, with the magnet arrangement in the inactive position.

(11) In FIGS. 1 to 7, a first embodiment according to the present invention of the magnetic isolating apparatus of the present application is labeled in general with the number 10. Magnetic isolating apparatus 10 encompasses a coupling arrangement 12 on which a guidance coupling point 14 is embodied at one end, and an apparatus coupling point 15 at the other end. Secured on guidance coupling point 14 is a guidance tube 16 in which a magnet arrangement 18 is guided shiftably along a guidance path F, depicted in FIG. 2, between the inactive position shown in FIG. 1 and the active position shown in FIG. 2. Guidance tube 16 extends along a tube axis R that is collinear with guidance path F.

(12) Apparatus coupling point 15 comprises a coupling configuration that is embodied for detachable coupling to a pipetting channel 20 of a pipetting apparatus 22. The coupling configuration of apparatus coupling point 15 corresponds to the coupling configuration of a pipetting tip detachably couplable onto pipetting channel 20.

(13) A pipetting piston 24 is received movably in a manner known per se in pipetting channel 20 that extends along a pipetting channel axis P, in order to allow the pressure of a working fluid in pipetting channel 20 to be modified by movement of pipetting piston 24 and thereby to allow, for example, an aspiration operation and/or a dispensing operation to be performed when a pipetting tip is coupled onto pipetting channel 20.

(14) In the present exemplifying embodiment, pipetting apparatus 22 constitutes a drive apparatus of magnetic isolating apparatus 10. Magnet arrangement 18 is therefore at least also fluidically coupled to pipetting apparatus 22 constituting the drive apparatus. Coupling arrangement 12 comprises for that purpose a connecting conduit 26 that passes centrally through it and passes completely through the coupling arrangement from apparatus coupling point 15 to guidance coupling point 14, so that pressure of the working fluid in pipetting channel 20 can act directly on magnet arrangement 18.

(15) Connecting conduit 26 is preferably embodied cylindrically. Its cylinder axis is collinear with pipetting channel axis P and also collinear with guidance path F (see FIG. 2). Isolating apparatus 10 furthermore comprises a schematically cup-shaped sheath 28 that is arranged detachably, namely slidably along guidance path F, on coupling arrangement 12 and on guidance tube 16. In order to achieve a high standard of hygiene, sheath 28 is replaced after each working operation, encompassing an immersion operation, of isolating apparatus 10. Sheath 28 is therefore a single-use or disposable sheath 28.

(16) Sheath 28 radially externally surrounds guidance tube 16 along its entire axial extent with respect to its tube axis, and constitutes an immersion portion 30 at its longitudinal end remote from coupling arrangement 12. This immersion portion 30 is embodied to be immersed into a suspension in order to remove magnetic particles therefrom as a result of the action of the magnetic field proceeding from magnet arrangement 18.

(17) Immersion portion 30 of sheath 18, and thus of isolating apparatus 10, is embodied with a smaller diameter than the remaining portion of sheath 28. The diameter of immersion portion 30 of sheath 28 is just large enough to accommodate the cylindrical magnet arrangement 18 therein.

(18) Magnet arrangement 18 is embodied as a solid cylindrical permanent magnet, whose cylinder axis is collinear with guidance path F (see FIG. 2) and which is preferably polarized along the cylinder axis, i.e. has a north or south pole at its one end and the respectively different (south or north) pole at its other end.

(19) At its longitudinal end facing toward coupling arrangement 12, magnet arrangement 18 is connected, for example by adhesive bonding, to a piston 32 for movement together. Piston 32, which is embodied to be substantially shorter than magnet arrangement 18 in the direction of guidance path F, for example less than a third the length of magnet arrangement 18, carries a sealing arrangement 34 that is movable along guidance path F together with piston 32 and seals against the inner side of guidance tube 16.

(20) Sealing arrangement 34 divides the volume enclosed by guidance tube 16, along guidance path F, into a displacement volume 36 located on that side of sealing arrangement 34 which faces away from coupling arrangement 12, and an actuation volume 38 located on that side of sealing arrangement 34 which faces toward coupling arrangement 12.

(21) In the inactive position, shown in FIG. 1, of magnet arrangement 18, actuation volume 38 is minimal and displacement volume 36 is maximal.

(22) Conversely, in the active position, shown in FIG. 2, of magnet arrangement 18, actuation volume 38 is maximal and displacement volume 36 is minimal but not zero.

(23) Actuation volume 38 and displacement volume 36 are variable depending on the relative position of magnet arrangement 18 and of sealing arrangement 34 which is connected thereto for motion together, the sum of actuation volume 38 and displacement volume 36 being substantially constant because of the invariable conformation of guidance tube 16.

(24) Guidance tube 16 and sheath 28 are manufactured from nonmagnetic and non-magnetizable material.

(25) Coupling arrangement 12 is equipped with ferromagnetic material at least at its guidance longitudinal end 14, so that in the inactive position shown in FIG. 1, magnet arrangement 18 is held, because of its magnetic field, in the inactive position by force interaction with coupling arrangement 12. Coupling arrangement 12 could thus be decoupled from pipetting channel 20 without causing magnet arrangement 18 to travel into the active position.

(26) FIG. 1 further depicts a container 40 in which a suspension (not depicted in further detail), made up of a liquid and magnetic particles received therein, is received. Container 40, which is radially externally substantially cylindrical, is received in a container carrier 42 that can likewise be part of isolating apparatus 10. Container carrier 42 comprises a shoulder 44, cylindrical in the exemplifying embodiment depicted, in whose surrounded recess 46 a bottom portion of container 40 is received.

(27) Shoulder 44, having receiving recess 46, is surrounded radially externally by a coil 48 of an electromagnet 50. Electromagnet 50 constitutes a control magnet arrangement for purposes of the present invention.

(28) Alternatively or additionally, a coil of an electromagnetic control magnet arrangement could also be received in coupling arrangement 12, for example surrounding connecting conduit 26. Electromagnet 50 is connected to a control device 52 (depicted only in FIG. 1 in the interest of clarity) that controls the operation of electromagnet 50. Control device 52 can be a control device of pipetting apparatus 22 which also controls the latter's operation. Control device 52 is therefore connected to electromagnet 50 via a signal- and/or energy-transferring lead 54, and can also be connected tin signal- and/or energy-transferring fashion to pipetting apparatus 22 via a lead 56 (depicted merely with dashed lines because it is optional).

(29) FIG. 2 depicts the apparatus of FIG. 1 with magnet arrangement 18 shifted into the active position.

(30) In order to shift magnet arrangement 18 into the active position, pipetting piston 24 was moved into the lower position shown in FIG. 2, with the result that the working fluid pressure in pipetting channel 20 became so greatly increased that magnet arrangement 18 became detached from its coupling arrangement 12, also embodied as a holding apparatus thanks to the use of ferromagnetic material at least at guidance coupling point 14, and became shifted into the active position shown in FIG. 2 in response to the elevated working fluid pressure together with the force of gravity acting along guidance path F.

(31) FIG. 3 depicts the apparatus of FIG. 2 with immersion portion 30 immersed into the suspension (not depicted). The permanent magnetic field proceeding from magnet arrangement 18 thus acts on the suspension.

(32) As a result of the shiftable permanently magnetic magnet arrangement 18, the magnetic field acting in the region of immersion portion 30 of isolating apparatus 10 is variable over time.

(33) FIG. 4 is an enlarged depiction of the region from coupling arrangement 12 to immersion portion 30 along with suspension container 40, so that further details of the apparatus can be explained in the enlarged depiction.

(34) As is evident from FIG. 4, there exists between coupling arrangement 12 and guidance tube 16 on the one hand, and that portion of sheath 28 which radially externally surrounds coupling arrangement 12 and guidance tube 16 on the other hand, an annular gap 58 that is connected toward apparatus coupling point 15, via introduction bevel 60 of sheath 28, to external environment U and thus to the atmosphere. External environment U exhibits a pressure level that is substantially constant except for the usual, and in the present case negligible, meteorological pressure fluctuations.

(35) At its longitudinal end located remotely from coupling arrangement 12, guidance tube 16 comprises passthrough openings 62 which pass through guidance tube 16 in a radial direction and through which annular gap 58 communicates with displacement volume 36 that is always present below sealing arrangement 34.

(36) That longitudinal end of guidance tube 16 which is located closer to the active position and farther from coupling arrangement 12 can thus be embodied, for example, in the manner of a crown, so that its peaks can constitute an end stop for shoulder 64, extending in a radial direction, of sheath 28, and the interstices between the peaks, constituting passthrough openings 62, can ensure communication between displacement volume 36 and external environment U.

(37) It is thereby possible, during a shift of magnet arrangement 18 from the inactive position into the active position, to push fluid, in particular gas, particularly preferably air, out of displacement volume 36 into external environment U and, upon shifting of magnet arrangement 18 in the opposite direction, i.e. toward the inactive position, to draw air out of external environment U into displacement volume 36 that is then getting larger, in order to allow fluidically and/or magnetically driven shifting of magnet arrangement 18 to be ensured even over long travel distances with no risk of a decrease, caused by the motion of magnet arrangement 18, in the pressure difference between the fluid pressures in actuation volume 38 and in displacement volume 36.

(38) Sheath 28 is brought close to the magnet arrangement 18 in the region of immersion portion 30 in order to avoid an unnecessary air gap and to achieve maximally effective action of the magnetic field, proceeding from magnet arrangement 18, on the suspension that then surrounds that portion 30. Immersion portion 30 is connected by way of the aforementioned shoulder 64 to that portion of sheath 28 which surrounds guidance tube 16 and coupling arrangement 12.

(39) Ribs can be embodied on coupling arrangement 12, on sheath 28, and/or on guidance tube 16, in particular in the region of that longitudinal end of guidance tube 16 which is closer to the active position, said ribs positioning coupling arrangement 12 and guidance tube 16 on the one hand, and sheath 28 on the other hand, radially with respect to one another so that annular gap 58 definitely exists. If they are embodied on coupling arrangement 12 and on guidance tube 16, the ribs protrude radially outward from them; if they are embodied on sheath 28, they protrude radially inward therefrom.

(40) Be it noted that an alternative embodiment of a piston 32′, which differs from piston 32 of FIGS. 1 to 3 and 5 to 7, is depicted in FIG. 4. In the embodiment of piston 32′ of FIG. 4, it is embodied in a double-T shape with an encircling groove in which seal arrangement 34′, having a sealing lip protruding therefrom, is arranged. Piston 32′ encompasses encirclingly, at its mounting longitudinal end, a longitudinal end, facing toward it, of cylindrical magnet arrangement 18, which simplifies the mounting of magnet arrangement 18 on piston 32′. This encompassing embodiment of the piston can also be implemented on piston 32.

(41) The advantage of fluidic actuation of magnetic arrangement 18 for shifting it between the inactive and active positions is that magnet arrangement 18 can be shifted regardless of any approach toward control magnet arrangement 50. It is thus possible to bring magnet arrangement 18 into the active position even before immersion portion 30 arrives in the vicinity of the suspension in which it is to be immersed.

(42) A comparable result could also be achieved, however, by providing a control magnet arrangement in coupling arrangement 12.

(43) The coupling arrangement could then be manufactured by injection-molding of thermoplastic, such that the coils of the control magnet arrangement can be embedded into the material of coupling arrangement 12 in a manner surrounding connecting conduit 26. If magnet arrangement 18 is to be shifted exclusively magnetically, connecting conduit 26 can also be omitted.

(44) A ferromagnetic cylinder can be embedded into coupling arrangement 12, manufactured by injection molding, in the region of its guidance coupling point 14; said cylinder, constituting a soft-magnet component, constitutes a holding apparatus for holding magnet arrangement 18 in the inactive position.

(45) FIG. 5 depicts the apparatus of FIG. 3 with no change of configuration except that because of the action of the magnetic field of magnet arrangement 18, a globule 66 of soft-magnetic particles from the suspension has become deposited around immersion portion 30.

(46) FIG. 6 shows isolating apparatus 10 in the configuration of FIG. 2 but with a particle globule 66 arranged on immersion portion 30.

(47) FIG. 7 shows isolating apparatus 10 immersed into an unloading vessel 68, with magnet arrangement 18 shifted into the inactive position. The shift is accomplished both by the fluidic coupling to pipetting piston 24 and by the action of control magnet arrangement 50. By way of the combined action of a fluid vacuum by means of pipetting piston 24 in pipetting channel 20 on the one hand, and a repulsive magnetic field effect thanks to control magnet arrangement 50, magnet arrangement 18 can be shifted at very high speed from the active position into the inactive position, with the result that the soft-magnetic particles initially adhering to immersion portion 30 are unloaded into unloading vessel 68.

(48) Unloading vessel 68 is identical in design to suspension vessel 40.

(49) FIGS. 8 to 9 depict a second embodiment of the magnetic isolating apparatus of the present invention, but without a pipetting apparatus as a drive apparatus.

(50) Components and component portions that are identical, and function identically, to those in the first embodiment are labeled in the second embodiment with the same reference characters but incremented by 100. The second embodiment will be described below only insofar as it differs from the first embodiment, to the description of which reference is otherwise expressly made for an explanation of the second embodiment as well.

(51) In the second embodiment, piston 132′ is connected via a piston rod 170 to magnet arrangement 118. Piston rod 170 is circularly cylindrical at least over a majority of its longitudinal extent, its cylinder axis being oriented collinearly with tube axis R of guidance tube 116.

(52) In guidance tube 116 itself, it is exclusively piston 132′ that is guided to move along guidance path F. Arranged at that longitudinal end of guidance tube 116 which is located closer to the active position (shown in FIG. 8) of magnet arrangement 118 is a guidance component 172 through which piston rod 170 passes with a small radial gap, so that guidance component 172 guides piston rod 170. As a result of the direct guidance of piston 132′ and of piston rod 170 respectively by guidance tube 116 and by guidance component 172, magnet arrangement 118 is indirectly guided to move along guidance path F. Magnet arrangement 118 is located completely outside guidance tube 116.

(53) As in the first exemplifying embodiment, sheath 128 is secured, with its longitudinal end farther from the active position (see FIG. 8), to coupling arrangement 112. FIGS. 8 and 9 depict grooves 174 embodied on coupling arrangement 112, which are arranged with an equidistant distribution in a circumferential direction around guidance path F and extend in their principal direction of extent along guidance path F. Gas-conveying conduit 158 between sheath 128 and guidance tube 116 is connected to external environment U by way of these grooves 174.

(54) Passthrough openings 162 which pass radially through the guidance tube, and through which displacement volume 136 (which is minimal in FIG. 8) is communicatingly connected to external environment U via gas-conveying conduit 158 and grooves 174, are in turn embodied in the region of that longitudinal end of guidance tube 116 which is closer to guidance component 172 and thus to the active position. In the second embodiment, passthrough openings 162 are provided with a spacing from that longitudinal end of the guidance tube which is closer to the active position, so that the longitudinal end itself can be used for the attachment of guidance component 172.

(55) FIG. 9 depicts the arrangement of FIG. 8, magnet arrangement 118 merely having been shifted into the inactive position. To allow the magnet arrangement to be held securely in the inactive position, guidance component 172 can act as a holding component, and for that purpose can be embodied in permanently magnetic or soft-magnetic fashion so that magnetic holding forces can act between guidance component 172 and magnet arrangement 118 in the inactive position.

(56) As is evident from FIGS. 8 and 9, sheath 128 is embodied to be considerably longer than guidance tube 116 in an axial direction. Sheath 128 both surrounds a majority of guidance tube 116, or in any event a majority of its extent proceeding from the longitudinal end located closer to the active position, and surrounds the entire shifting travel length of magnet arrangement 118.

(57) Guidance component 172 can project radially externally beyond guidance tube 116 in order to brace sheath 128 radially.