EP2148738B1 - Method for mixing and/or conveying, mixing and/or conveyance device, and sample processing chip comprising such a device - Google Patents

Abstract

A mixing and/or conveyance method and a mixing and/or conveyance device for a fluid substance, comprising a sample chamber, a cavity communicating with the sample chamber, said cavity being configured for accommodating a compressible medium, and a sound source that may be coupled to the compressible medium for the production of a fluctuation in pressure in the compressible medium. In the region of its mouth, the cavity is designed such that, in the case of an expansion in the volume of the compressible medium in the cavity, a directed fluid stream of the fluid substance escapes from the cavity through its mouth. A sample processing chip (‘lab on a chip’) comprising such a mixing and/or conveyance device.

Description

The invention relates to a mixing and / or conveying method and a mixing and / or conveying device for a flowable substance or liquid having a sample chamber, a communicating with the sample chamber cavity, which is adapted to receive a compressible medium volume, and one to the compressible medium coupling sound source for generating a pressure oscillation in the compressible medium. The invention further relates to a sample preparation chip ("lab on a chip") with such a mixing and / or conveying device.

While different methods and devices, such as magnetic stirrers, vortex mixers and the like are used for mixing macroscopic amounts of liquid, these are usually unsuitable for microscopic amounts of liquid. In particular, such mixing principles can not be integrated into existing sample conditioning systems.

In microfluidics, therefore, mostly passive mixing methods and devices are used. Such also mostly continuously operated mixing method and mixers, such as those used in chemical process or process technology are, for example, from EP 1311341 B1 or the EP 1390131 B1 known. These methods and mixers are usually unsuitable for mixing small amounts of liquid.

A new procedure will be in the US 2003/0175947 A1 and in the article " Bubble-induced acoustic micromixing "by Robin H. Liu et al., LAB Chip, 2002, 2, 151-157 , described. In it a device for mixing smallest amounts of liquid (22 ul) is presented, which has a chamber filled with the liquids to be mixed, and peripherally disposed and connected to the chamber cavities. In the area of the cavities, air bubbles are trapped, which are put into resonant oscillation by acoustic excitation, thereby also causing the surrounding liquid to move, which leads to a faster mixing in comparison with the diffusion mixture. In the corresponding model, it is assumed by the authors that the microflow produced in this way is based on the frictional forces at the interface between the liquid and the gas bubble.

From the same mixing principle go the pamphlets WO 2006/105616 A1 and WO 2004/030800 A2 out.

The essay "The 'acoustic scallep': a bubble-powered actuator" by Dijkink, R. et al., Journal of Micromechanics and Microengineering, Institute of Physics Publishing, Bristol, UK; Vol. 16, No. 8 discloses a mixing and / or conveying device according to the preamble of claim 1.

In contrast, the invention has the object to achieve an improved mixing and pumping action.

The object is achieved by a mixing and / or conveying device according to claim 1.

The inventive method for mixing and / or conveying a flowable substance in a sample chamber, in particular for microfluidic mixing and / or conveying, accordingly provides that a compressible medium in a cavity opening into the sample chamber by means of sound coupling to a pressure oscillation is excited, wherein a portion of the flowable substance penetrates into the mouth region of the cavity and emerges as a result of a volume expansion of the compressible medium in a directed fluid flow through the mouth of the cavity.

With sample chamber or chamber is in the context of the invention quite generally an arbitrarily shaped volume with one or more openings in which the flowable substance is trapped or which is flowed through by the flowable substance - even during mixing - meant.

The term cavity is herein, unless specified, generally understood as a cavity of any shape. The term "opening" used below describes the exit cross-section of the cavity in projection onto the body surface at the exit point. The mouth is the opening-near end section or outlet channel of the cavity.

As described above, the "bubbles" of the compressible medium trapped in the cavities are exposed to pressure fluctuations due to acoustic excitation. The resulting from the pressure drop volume expansion of the compressible medium according to the invention but used to form a directed fluid flow of the flowable substance through the mouth of the cavity. The cavity must therefore be formed in the mouth region so that a directed jet (or jet) emerges from this, which ensures a momentum transfer to the flowable substance located in the chamber. The direction of flow of the exiting fluid jet can be adjusted on the one hand by the orientation of the cavity or its mouth, on the other hand by the arrangement or shape of the opening or by a combination of both features.

Preferably, the cavity has at least one channel-shaped mouth in the sample chamber.

In a simple configuration, the cavity has, for example, a tubular section with a constant cross-section, at least in the area of the mouth, in a complicated configuration a special nozzle geometry in order, for example, to increase the efficiency of the drive.

The invention thus makes use of another principle, namely that with a sufficiently large Reynolds number, Re ≥ about 50, a fluid exiting a channel leaves in the form of a directed jet while a fluid drawn into the channel exits the entire available solid angle area equally enters the channel. The principle is in the essay " The 'acoustic scallop': a bubble-powered actuator "by Dijkink et al., Journal of Micromechanics and Microengineering, 16, 2006, 1653-1659 , described. There it is proposed to use the principle as a drive for an "acoustic windmill". A teflon tube closed on one side is accordingly immersed in a container filled with water, after which an air bubble is enclosed in its capillary. Sound is coupled by means of a piezoelectric actuator through the water in the bubble, which is thereby excited to a vibration. The alternating volume expansion and contraction alternately draws fluid into the tube and expels it again. Due to the described asymmetry between the directed ejection and the undirected sucking results over a full swing, a total momentum transfer to the tube, which is used to drive it in the direction of its longitudinal axis.

Unlike in the article in the present case, the principle is not used to drive but to bring a net impulse entry in the standing or flowing liquid and thereby in interaction with the geometry of the sample chamber and the arrangement of the cavities to achieve increased turbulence and thus improved mixing of the liquids on the one hand and / or (improved) transport of the liquids in a particular direction.

Preferably, the surface of the cavity is arranged to at least partially not wet.

In this way it is ensured that an air bubble trapped in the cavity remains trapped there due to the surface tension of the flowable substance.

The surface of the cavity is designed to wet in the mouth area.

This ensures that part of the flowable substance or liquid enters at least into the mouth region due to the capillary effect and is ready there as a liquid column for forming the fluid stream.

A local wettability or non-wettability of the surfaces can be achieved by surface modification.

When used for an aqueous solution, the mixing and / or conveying device is formed, for example, either from a hydrophobic material and hydrophilized in the area of the mouth and, if necessary, in other surface areas outside the cavity or it is formed from a hydrophilic material and in the region of the cavity ( en) optionally hydrophobicized except the mouth (s).

The hydrophilization or hydrophobing can be carried out in a known manner by a dipping method, as in DE 100133111 C2 described, or by a coating. Polycarbonate can be hydrophilized, for example, as a weakly hydrophobic material by an O 2 plasma treatment on the surface.

When using the mixing and / or conveying device for non-polar organic liquids, correspondingly lipophilic surfaces in the region of the orifice and, as far as necessary, in other surface areas as well as lipophobic surfaces in the region of the cavity (s) may optionally be used apart from the orifice (s). This is preferably done by the mixing and / or conveying device is formed from a lipophilic material and optionally lipophobic in the region of the cavity except the mouth or by being formed from a lipophobic material and in the region of the mouth and as necessary in other surface areas outside the cavity is lipophilized.

In an advantageous development, the mixing and / or conveying device has a pressure increasing means communicating with the sample chamber, which is set up to apply a pressure to the flowable substance or liquid so that a portion of the flowable substance is compressed in compression of the compressible medium penetrates the mouth region of the cavity.

As an alternative or in addition to the wettable mouth region, it is also ensured in this way that sufficient flowable substance is available as a liquid column for forming the fluid stream in the mouth region of the cavity.

In the embodiment of the method, the compressible medium exits through the mouth or orifices relative to the sample chamber such that a net angular momentum is introduced into the flowable substance in the sample chamber. The corresponding mixing and / or conveying device has cavities with openings in the sample chamber, which are arranged and arranged relative to the sample chamber so that by means of the volumetric expansion of the compressible medium through the orifices emerging from the cavities directed fluid flows a sum-angular momentum in the flowable substance is introduced within the sample chamber.

In this way, the entire liquid in the sample chamber is placed in a rotational movement. This ensures an overall greater turbulence in the entire sample chamber. The danger that in "dead corners" does not take place sufficient mixing is reduced.

In an alternative preferred embodiment, the compressible medium exits through the mouth or orifices relative to the sample chamber such that a net linear momentum is introduced into the flowable substance in the sample chamber. The corresponding mixing and / or conveying device has cavities with openings in the sample chamber, which are arranged and arranged relative to the sample chamber so that by means of the volumetric expansion of the compressible medium through the orifices emerging from the cavities, directed fluid streams a sum linear pulse in the flowable substance is introduced within the sample chamber.

In this way, a pumping effect is achieved which conveys the fluid in the sample chamber in one direction, for example from an inlet opening towards an outlet opening.

The cavity is introduced in the simplest and therefore most cost-effective case in the form of a death or a single-sided closed channel in a wall of the sample chamber.

The sound source is preferably coupled directly to a sample chamber wall.

If the sound source in a region of the sample chamber wall is connected to the mixing and / or conveying device, which is in contact with the flowable substance when operating, the pressure oscillation is coupled out directly via the flowable substance and passed on to the compressible medium. In this way, losses due to greater differences in impedance in the sound transmission, for example, avoided by an adjacent on the inside of the container wall air / gas cushion.

In another advantageous embodiment, the cavity is designed in the form of a connecting channel, which is connected on the one hand via the mouth to the sample chamber and on the other hand with a filled with a coupling medium pressure chamber to which the sound source is coupled.

The pressure oscillation is thus not coupled via the substance to be mixed but to a certain extent from the opposite side via the coupling medium in the pressure chamber into the compressible medium. A corresponding channel system for the coupling medium can supply several / all cavities from a central pressure chamber. The advantage here is that by a valve control the cavities can be controlled individually or in groups in the desired arrangement.

The compressible medium is preferably gas, more preferably air.

Figur 1

einen Querschnitt durch die erfindungsgemäße Mischvorrichtung in einem Probenaufbereitungschip gemäß einer ersten Ausführungsform von der Seite betrachtet;

Figur 2

die erfindungsgemäße Mischvorrichtung gemäß einer zweiten Ausführungsform im Schnitt von oben;

Figur 3

einen Querschnitt durch die erfindungsgemäße Fördervorrichtung gemäß einer weiteren Ausführungsform;

Figur 4

einen Probenaufbereitungschip mit zwei hintereinander geschalteten Mischvorrichtungen und externer Druckkammer im Schnitt von oben;

Figur 5

einen Querschnitt durch die erfindungsgemäße Mischvorrichtung in einem Probenaufbereitungschip gemäß einer weiteren Ausführungsform von oben und.

Figur 6

einen Querschnitt durch den düsenförmigen Mündungsbereich einer Kavität.

Other objects, features and advantages of the invention will be explained in more detail by means of embodiments with the aid of the drawings. Show it:

FIG. 1

a cross-section through the mixing device according to the invention in a sample processing chip according to a first embodiment viewed from the side;

FIG. 2

the mixing device according to the invention according to a second embodiment in section from above;

FIG. 3

a cross section through the conveyor device according to the invention according to a further embodiment;

FIG. 4

a sample preparation chip with two mixing devices connected in series and external pressure chamber in section from above;

FIG. 5

a cross section through the mixing device according to the invention in a sample processing chip according to another embodiment from above and.

FIG. 6

a cross section through the nozzle-shaped mouth region of a cavity.

In FIG. 1 the simplest embodiment of the mixing device according to the invention is shown. A sample chamber 100 is in the form of a Channels having a constant cross section or a sample chamber which widens transversely to the section plane are introduced into a sample preparation chip 110. A liquid drop 112 of the substance to be mixed (hereinafter also referred to as "plug"), to be recognized at the interfaces 113 and 114 to the surrounding air / gas, is conveyed through the channel 100, for example by a pump (not shown).

Located transversely to the channel 100 is a cavity 116 which in this case opens from below into the channel 100 and which is designed in the form of a small, non-vented channel or a dead bore. When the liquid drop 112 reaches the area around the cavity 116, as in FIG Fig. 1 1, an air or gas bubble 118 is enclosed in the cavity 116 therein as a compressible medium.

Decisive for the active principle according to the invention is that the liquid to be mixed at least partially penetrates into the mouth region of the cavity 116 and there provides a liquid column, indicated by the interface 120 between the air bubble 118 and the liquid plug 112. For forming this liquid column can two different Mechanisms are used selectively or simultaneously. On the one hand, it will be ensured that the cavity 116 wets in its mouth region. This can be achieved by a suitable choice of the material of the cavity in the mouth region, ie, if appropriate, by a surface modification, if the cavity is formed, for example, from an otherwise non-wettable material. Alternatively or additionally, the liquid plug 112 can be pressurized by the pump connected to the channel 100, whereby the air bubble 118 trapped in the cavity 116 is compressed. In this case, care must be taken by a suitable measure that the liquid plug 112 when reaching the target pressure is exactly above the Cavity 116 is located. This can be done by pressurizing the liquid plug 112 on both sides.

On top of the sample processing chip 110, a sound source in the form of a piezoactuator 122 is mounted. The piezoelectric actuator 122 is connected to an AC voltage source 124, which excites him to a vibration. When using a piezoelectric actuator, make sure that it is preloaded. In the sample preparation chip according to FIG. 1 For this purpose, it can be pressed onto a suitable wall 111 via sample chamber 100, which in practice is formed on top by a cover foil. The vibration is coupled via the wall 111 of the sample processing chip 110 with respect to the cavity 116 in the liquid plug 112 and forwarded by this. The fact that the coupling takes place in an area which is in direct contact with the liquid plug 112, the sound is coupled directly into the flowable substance and there are no major losses due to impedance differences, for example, by an intermediate layer of air. By setting a corresponding frequency, the coupled-in sound can be adapted to the resonance frequency of the air bubble 118 enclosed in the cavity 116. This ensures an increase in the amplitude of the oscillation in the cavity and thus an efficient utilization of the coupled-in sound.

By oscillation of the air bubble 118, the liquid column standing in the mouth region of the cavity 116 is sucked or expelled. The ejection of the liquid column takes place, as indicated by the arrow 126, directed, while the suction of the liquid from the sample chamber 100 from all available directions takes place at almost the same speed. This results in a net impulse entry in, considering a full oscillation the liquid plug 112 in the direction of the arrow. The liquid in the plug 112 is thereby swirled and the mixing accelerated.

The cross-section of the cavity 116 is typically smaller than that of the channel or sample processing chamber 100, so that the amount of liquid that is drawn in and expelled does not already comprise a majority of the liquid amount of the entire plug 112. While the channel cross-section or the height of the sample chamber 100 is typically several tenths of a millimeter to a few centimeters, the diameter of the cavity 116 is only several microns to a few millimeters, preferably a few tenths of a millimeter in size. The length of the Kavltät 116 may be 0.5 mm to 50 mm, which ensures that a sufficiently large amount of air in the cavity 116 is ready for compression.

In FIG. 2 For example, a sample chamber 200 in a sample conditioning chip 210 is shown from above. The sample chamber 200 is bulged in the lateral extension direction and of approximately circular cross-section. The chamber may have a constant height, an expansion or a constriction in the vertical direction perpendicular to the plane of the illustration.

The sample chamber 200 is connected on the input side to a feed 202 for the flowable substance to be mixed and on the output side to a discharge 204. In the sample chamber 200 there is a liquid drop or plug 212, which can be recognized at the interfaces 213, 214. Around the sample chamber 200 are arranged four cavities 216, which open tangentially into them.

If sound is coupled into the liquid by means of a sound source (not shown), air bubbles trapped in the cavities 216 are blown out, as in connection with the example FIG. 1 described, vibrated. As a result, a tangential net pulse entry into the liquid in the chamber 200 results from each cavity 216. The pulses add up due to the arrangement of the four cavities 216 such that the liquid in the plug 212 is rotated. This arrangement is advantageous for mixing larger amounts of liquid.

A uniform pulse input from all four cavities 216 is only ensured if the air bubbles trapped therein have the same dimensions, since only then all four are equally resonated by the same frequency. But you can also consciously take advantage of resonance differences. For example, two of the four cavities may open into the sample chamber in the opposite tangential direction. If the respectively rectified cavities have the same dimensions but the opposing cavities have different, their resonant frequency is also different. Thus, by tuning the coupled sound frequency alternately a rotation in one direction and then in the other direction can be excited. This change will create a chaotic flow pattern and thus an even better mixing of the liquid.

In FIG. 3 an embodiment of the conveyor device according to the invention is shown in cross section, which in turn comprises a sample chamber 300 in the form of a channel in a sample processing chip 310. Furthermore, the conveying device has a plurality of cavities 316 which open at an acute angle to the longitudinal axis of the channel 300 in the same. In the channel 300 is a liquid which penetrates in the manner described above in the mouths of the cavities 316 and therein includes an air bubble. If this is set in pressure oscillation by a sound source, then in the manner described above, the liquid column from the mouth region each cavity (synchronously) conveyed out. The pulse inputs into the liquid in the channel add up to a net linear pulse in the direction of the channel axis, indicated by arrow 326. In this way, a micro-pumping device is provided.

In FIG. 4 2 shows a section of a sample preparation chip 410 with two sample chambers 400, 401, into each of which two feeds 402, 403 or 404, 405 open. The sample chambers are connected directly one behind the other, so that the discharge 406 of the first sample chamber 400 opens directly into one of the feeders 404 of the second sample chamber 401. Thus, while in the sample chamber 400, the substances A and B introduced through the feeders 402 and 403 are mixed into a mixed substance A + B, in the second sample chamber 401, the mixed substance A + B with another substance C becomes the mixed substance A + B + C mixed.

The mixing takes place on the basis of the previously described principle. A cavity 416 or 417 respectively opens into both sample chambers. If the liquid plug consists of the two initially unmixed substances A and B in the first sample chamber 400, an air or gas bubble 418 is enclosed in the cavity 416. In contrast to the exemplary embodiments described above, however, the cavity 416 is not a dead bore closed on one side, but rather a connecting line, which is connected at the rear to a pressure chamber 430 which is filled with a coupling medium. The air bubble 418 is enclosed between the substance to be mixed on the one hand and the coupling medium on the other. A sound field is preferably coupled in the manner described above by coupling a sound source in the region of the pressure chamber 430 in the coupling medium. This emits the vibration to the air or gas bubble, which pulsates due to its compressibility and the Flow of the flowable substance caused in the mouth of the cavity.

If the two substances A and B are sufficiently mixed, the liquid plug of the mixed substance A + B is transported in the direction of the second sample chamber 401, where it is combined with the substance C.

The pressure chamber can be connected by a branched line system both with the cavity 416 opening into the first sample chamber 400 and with the cavity 417 opening into the second sample chamber 401. Therefore, only one sound source, which is connected to the common pressure chamber 430, is required for mixing in both sample chambers 400, 401.

A switched into the line of the coupling medium valve 432 is switched after the mixing process in the first sample chamber 400, so that subsequently only the opening into the second sample chamber 401 cavity 417 is connected to the pressure chamber 430. Now, an air bubble (not shown) enclosed in the cavity 417 can be vibrated via the coupling medium and the substances A, B and C are mixed.

The supply and removal of the substances A, B and C is carried out by a suitable, not shown here in detail valve system, so as to ensure that the substances take the right path and remain during mixing in the respective mixing chambers.

In FIG. 5 Again, a simple embodiment of the mixing device according to the invention in a sample processing chip 510 is shown. A sample chamber 500 is formed in the form of a bulbous volume in the lateral extension direction. The chamber 500 may be in vertical direction perpendicular to the plane of representation have a constant height, an expansion or a constriction.

The sample chamber 500 is connected on the input side to a feed 502 for the flowable substance to be mixed and on the output side to a discharge 504. In contrast to the sample chamber according to FIG. 2 For example, the supply and discharge each have bottlenecks or constrictions 506 and 508, respectively. In the sample chamber 500 is a liquid drop or plug 512, visible at the interfaces 513, 514. The volume of the liquid drop 512 is tuned to the volume of the chamber that the interfaces 513, 514 in the region of the bottlenecks 506, 508 to come lie. This has two advantages: the liquid drop 512 can be more easily held in the sample chamber and the injected sound can be used more efficiently due to the small adjoining areas 513, 514 - less noise energy is extracted. The liquid drop 512 is held or positioned more easily by virtue of the fact that the surface of the chamber 500 and the feed and discharge 502, 504 are preferably designed to be wettable. As a result, the flowable substance penetrates into the bottlenecks and stops at its transition to the further downstream section of the discharge 504. In order to move the liquid further out of the chamber 500, energy must be expended, since an increase in surface area takes place. The liquid is therefore kept safely in the chamber, as long as no sufficient energy is applied for further transport.

The cavity 516 is in this case central and transverse to the axis formed by the supply and the discharge. It is, as in the example of FIG. 1 formed in the form of a small, non-vented channel or a dead bore. The operating principle is the same.

The illustrated embodiments of the mixing device according to the invention are particularly suitable for continuous or quasi-continuous operation. By quasi-continuous in this context is meant a sequentially operating mixing device, in which individual volumes of the liquid are successively passed through the sample chamber and mixed.

The sample chamber is - regardless of the other shape - preferably formed without sharp corners or edges and with a streamlined shape so that at low flow locations or in the corners and edges remain no liquid residues and the chamber can be filled as completely as possible and emptied.

This preferably also relates to the cavity 616 of the mixing and / or conveying device according to the invention, which has an orifice 634 in the form of a nozzle with a flow-wise tapered mouth opening in the direction of the opening 636 and a sharp tear-off edge in the opening plane, as in FIG FIG. 6 is shown schematically.

LIST OF REFERENCE NUMBERS

100

Sample chamber / channel

110

Sample processing chip

111

wall

112

Liquid drop / plug

113

interface

114

interface

116

cavity

118

bubble

120

interface

122

Piezzoaktor

124

AC voltage source

126

pulse

200

sample chamber

202

feed

204

removal

210

Sample processing chip

212

Liquid drop / plug

213

interface

214

interface

216

cavity

226

angular momentum

300

sample chamber

310

Sample processing chip

316

cavity

326

Net Pulse

400

sample chamber

401

sample chamber

402

feed

403

feed

404

feed

405

feed

406

removal

407

removal

410

Sample processing chip

416

cavity

417

cavity

418

bubble

430

pressure chamber

432

Valve

500

sample chamber

502

feed

504

removal

506

bottleneck

508

bottleneck

510

Sample processing chip

512

Liquid drop / plug

513

interface

514

interface

516

cavity

616

cavity

634

mouth area

636

opening

Claims (12)

1. Mixing and/or conveyance device for a flowable substance, comprising a sample chamber (100), a cavity (116), which opens out into the sample chamber (100), is designed to receive a compressible medium of a specific volume and is formed in the orifice region in such a way that, if the volume of the compressible medium in the cavity expands, a directed fluid stream of the flowable substance escapes from the cavity (116) through the orifice, and a sound source, which couples to the compressible medium, for generating a pressure oscillation in the compressible medium, characterized in that the surface of the cavity (116) is designed to be wetted in the orifice region.
2. Mixing and/or conveyance device according to Claim 1, characterized in that the surface of the cavity (116) is designed at least partially not to be wetted.
3. Mixing and/or conveyance device according to either of the preceding claims, characterized by a pressure-increasing means, which is connected to the sample chamber (100) and is designed to pressurize the flowable substance, such that some of the flowable substance passes into the orifice region of the cavity (116) under compression of the compressible medium.
4. Mixing and/or conveyance device according to one of the preceding claims, characterized in that cavities (116) have orifices into the sample chamber (100) which are arranged and designed in relation to the sample chamber (100) in such a way that the directed fluid streams escaping from the cavities (116) through the orifices introduce a sum angular momentum into the flowable substance within the sample chamber (100).
5. Mixing and/or conveyance device according to one of the preceding claims, characterized in that cavities (116) have orifices into the sample chamber (100) which are arranged and designed in relation to the sample chamber (100) in such a way that the directed fluid streams escaping from the cavities (116) through the orifices introduce a sum linear momentum into the flowable substance within the sample chamber (100).
6. Mixing and/or conveyance device according to one of the preceding claims, characterized in that the cavity (116) is introduced into a wall of the sample chamber (100) in the form of a dead hole.
7. Mixing and/or conveyance device according to one of the preceding claims, characterized in that the sound source is coupled directly to the sample chamber wall.
8. Mixing and/or conveyance device according to one of Claims 1 to 7, characterized in that the cavity (116) is in the form of a connection channel, which is connected on the one hand to the sample chamber (100) via the orifice and on the other hand to a pressure chamber, which is filled with a coupling medium and to which the sound source is coupled.
9. Mixing and/or conveyance device according to one of the preceding claims, characterized in that the compressible medium is a gas.
10. Mixing and/or conveyance device according to one of the preceding claims, characterized in that the compressible medium is air.
11. Sample processing chip (110) comprising a mixing and/or conveyance device according to one of the preceding claims.
12. Method for mixing and/or conveying a flowable substance in a sample chamber (100) in a mixing and/or conveyance device according to one of Claims 1 to 10, in which method a compressible medium is made to perform a pressure oscillation by means of the injection of sound in a cavity (116) which opens out into the sample chamber (100), wherein some of the flowable substance passes into the orifice region of the cavity (116) and, as a result of an expansion in the volume of the compressible medium, escapes from the cavity (116) through the orifice in a directed fluid stream in such a manner that a net angular momentum is introduced into the flowable substance in the sample chamber (100).

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