Method and statistical micromixer for mixing at least two liquids

• US 20040027915A1
• Filed: 07/28/2003
• Published: 02/12/2004
• Est. Priority Date: 08/25/2000
• Status: Active Grant

• Current Assignee: Institute Fur Mikrotechnik Mainz GmbH, Mikroglas Chemtech GmbH
• Original Assignee: Mikroglas Chemtech GmbH
• Inventors: Hessel, Volker, Schiewe, Jorg, Freitag, Andreas, Lowe, Holger, Dietrich, Thomas
• Granted Patent: US 6,935,768 B2
• Time in Patent Office: Days
• US Class Current: 366/341
• CPC Class Codes: B01F 25/23 Mixing by intersecting jets
• CPC Class Codes: B01F 25/25 Mixing by jets impinging against collision plates
• CPC Class Codes: B01F 25/312 with Venturi elements; Details thereof
• CPC Class Codes: B01F 25/433 Mixing tubes wherein the shape of the tube influences the mixing, e.g. mixing tubes with varying cross-section or provided with inwardly extending profiles
• CPC Class Codes: B01F 25/4338 Mixers with a succession of converging-diverging cross-sections, i.e. undulating cross-section
• CPC Class Codes: B01F 33/3011 using a sheathing stream of a fluid surrounding a central stream of a different fluid, e.g. for reducing the cross-section of the central stream or to produce droplets from the central stream
• CPC Class Codes: B01F 33/3012 Interdigital streams, e.g. lamellae
• CPC Class Codes: B01F 33/3039 with mixing achieved by diffusion between layers
• CPC Class Codes: B01F 33/3045 using turbulence on microscale
• CPC Class Codes: B01F 35/514 the mixing receptacle or conduit being transparent or comprising transparent parts
• CPC Class Codes: B01J 19/0093 Microreactors, e.g. miniaturised or microfabricated reactors laboratory containers with capillary fluid transport in microfabricated channels or chambers B01L3/5027
• CPC Class Codes: B01J 2219/00783 Laminate assemblies, i.e. the reactor comprising a stack of plates
• CPC Class Codes: B01J 2219/00826 Quartz
• CPC Class Codes: B01J 2219/00831 Glass
• CPC Class Codes: B01J 2219/00835 Comprising catalytically active material
• CPC Class Codes: B01J 2219/0086 Dimensions of the flow channels
• CPC Class Codes: B01J 2219/00889 Mixing micromixers B01F33/30
• CPC Class Codes: B81B 1/00 Devices without movable or flexible elements, e.g. microcapillary devices
• CPC Class Codes: Y10S 366/03 Micromixers: variable geometry from the pathway influences mixing/agitation of non-laminar fluid flow

Abstract

The invention relates to a procedure and a micromixer for mixing at least two fluids. The aim of the invention is to reduce the mixing time of the micromixer compared to micromixers known to the art while maintaining high mixing quality and small structural dimensions. The inventive procedure is characterized by the following steps: a plurality of separated fluid currents of both fluids are brought together and alternately adjacent fluid lamellae of both fluids are formed: the combined fluid currents are carried away and a focused total fluid current is formed; the focused total fluid current is fed as fluid jet into an expansion chamber; and the resulting mixture is drawn off. The micromixer comprises a plurality of alternately adjacent fluid channels (2, 3) which open into an inlet chamber (4). A focusing channel (5) is in fluid connection with said inlet chamber and opens into an expansion chamber (6). The inventive procedure and micromixer are especially advantageous in that they are suitable for the production of emulsions and dispersions.

Claims

1. Procedure for mixing at least two fluids comprising the following steps:

a multitude of separate fluid currents of the two fluids, each of a width in the range of 1 μ

m to 1 mm and a depth in the range of 10 μ

m to 10 mm, are brought together and alternately adjacent fluid lamellae of the two fluids are generated;

the combined fluid currents are carried away and a focused total fluid current is generated;

the focused total fluid current is fed as fluid jet into an expansion chamber with a larger cross section than the focused total fluid current perpendicular to the flow direction of the focused total fluid current;

the resulting mixture is drawn off.

2. Procedure according to claim 1, characterized by the fact that the combined fluid currents are focused in such a way that the ratio between the cross section of the focused total fluid current and the sum of the cross sections of the fluid currents to be combined, all perpendicular to the flow direction, is in the range of 1:

1 to 1;

500, preferably in the range of 1;

2 to 1;

50.

3. Procedure according to one of claims 1 or 2, characterized by the fact that the ratio of the length of the focused total fluid current and its width is in the range of 1:

1 to 30;

1, preferably in the range of 1.5;

1 to 10;

1.

4. Procedure according to one of the previous claims, characterized by the fact that the focused total fluid current enters the expansion chamber as fluid jet in such a way that stationary vortices are generated on both sides of the fluid jet on at least one plane.

5. Procedure according to one of the previous claims, characterized by the fact that after having been fed into the expansion chamber, at least part of the fluid current is drawn off while again being focused.

6. Procedure according to one of the previous claims, characterized by the fact that the following two steps are executed once or in several repetitions:

after previously being fed into the expansion chamber, at least part of the fluid current is carried away and forms a focused fluid current;

the focused fluid current is fed into an additional expansion chamber having a larger cross section than the focused fluid current perpendicular to the flow direction of the focused fluid current;

wherein the resulting mixture is drawn off after the last step.

7. Procedure according to one of the previous claims, characterized by the fact that an additional fluid, as for example a fluid containing an additive for stabilizing the mixture, is fed into the expansion chamber.

8. Procedure according to one of the previous claims, characterized by the fact that at least part of the resulting mixture is drawn off the area or areas of the expansion chamber with vortices being generated.

9. Procedure according to one of the previous claims, characterized by the fact that the first two steps are each executed twice or several times, simultaneously and spatially separately, and that the resulting two or more focused total fluid currents are fed into the common expansion chamber.

10. Static micromixer (1) for mixing at least two fluids, with

a multitude of alternately adjacent fluid channels (2, 3) of a width in the range of 1 μ

m to 1 mm and a depth in the range of 10 μ

m to 10 mm for separately supplying the fluids as fluid currents;

an inlet chamber (4) into which the fluid channels enter;

a focusing channel (5) fluidly connected to the inlet chamber (4) for carrying away the fluid currents combined in the inlet chamber (4) and generating a focused total fluid current;

an expansion chamber (6), into which the focusing channel (5) enters and into which the focused total fluid current runs as fluid jet, with a larger cross section than the focusing channel (4) perpendicular to the axis of the focusing channel (4), and

at least one outlet channel (7) fluidly connected to the expansion chamber (6) for drawing off the resulting mixture.

11. Static micromixer according to claim 10, characterized by the fact that in its interior the inlet chamber (4) has a concave or semi-concave shape on at least one plane, wherein the concave surface (8) into the center of which the focusing channel (5) runs is located opposite the surface into which the fluid channels enter.

12. Static micromixer according to claim 10 or 11, characterized by the fact that the ratio between the cross section of the focusing channel (5) and the sum of the cross sections of the fluid channels (2, 3) entering into the inlet chamber (4), always perpendicular to the channel axis, is in the range of 1:

1.5 to 1;

500, preferably in the range of 1;

2 to 1;

50.

13. Static micromixer according to one of claims 10 through 12, characterized by the fact that the ratio between the length of the focusing channel (5) and its width is in the range of 1:

1 to 30;

1, preferably in the range of 1.5;

1 to 10;

1.

14. Static micromixer according to one of claims 10 through 13, characterized by the fact that the ratio between the cross section of the expansion chamber (6) and the cross section of the focusing channel (5) entering into the expansion chamber, in at least a central area, perpendicular to the channel axis is in the range of 1.5:

1 to 500;

1, preferably in the range of 2;

1 to 50;

1.

15. Static micromixer according to one of claims 10 through 14, characterized by the fact that the expansion chamber (6) opens into an additional focusing channel (5′

) serving as outlet channel (7) for drawing off and re-focusing at least part of the total fluid current.

16. Static micromixer according to one of claims 10 through 15, characterized by a sequence of one or several additional focusing channels (5′

, 5″

) into which open the respective upstream expansion chambers (6, 6′

, 6″

) for drawing off and focusing at least part of the total fluid current, and one or several additional expansion chambers (6′

, 6″

) into which the respective upstream additional focusing channels (5′

, 5″

) enter, and with at least one outlet channel (7) fluidly connected to the last expansion chamber (6″

) in the sequence for drawing off the resulting mixture.

17. Static micromixer according to one of claims 10 through 16, characterized by the fact that one or several supply channels (9a, 9b) enter into the expansion chamber (6) for supplying an additional fluid, such as for example a fluid containing an additive for stabilizing the mixture.

18. Static micromixer according to one of claims 10 through 17, characterized by one or several additional outlet channels (10a, 10b) connected to the expansion chamber (6) for drawing off the resulting mixture.

19. Static micromixer according to one of claims 10 through 18, characterized by a deflector structure (11) disposed in the expansion chamber (6) for the purpose of deflecting the fluid jet.

20. Static micromixer according to one of claims 10 through 19, characterized by the fact that the multitude of adjacent fluid channels (2, 3;

12, 13), the inlet chamber (4;

14) into which the fluid channels (2, 3;

12, 13) enter, and the focusing channel (5;

15) fluidly connected to the inlet chamber (4;

14) each are provided two or several times and that the two or more focusing channels (5;

15) enter into a common expansion chamber (16).

21. Static micromixer according to one of claims 10 through 20, characterized by the fact that the structures of the fluid channels (2, 3), of the inlet chamber (4), of the focusing channel (5), and of the expansion chamber (6) are constructed as recesses and/or penetrations in a plate serving as mixing plate (20) and manufactured of a material sufficiently inert for the fluids to be mixed, and that these open structures are closed in by a cover and/or base plate (21, 22) fluidly connected to the mixing plate, wherein the cover and/or base plate (21, 22) are equipped with supply devices (23, 24) for the two fluids and/or at least one outlet (25) for the resulting mixture.

22. Static micromixer according to claim 21, characterized by a distribution plate (26) located between the mixing plate (20) and the base plate (22), fluidly tightly connected to the same and serving the purpose of separately supplying the fluids from the supply devices in the base plate (22) to the fluid channels (2, 3) in the mixing plate (20).

23. Static micromixer according to one of claims 21 or 22, characterized by the fact that at least the mixing plate (20) and the cover and/or base plate (23, 24) are manufactured from a transparent material, in particular, glass or quartz glass.