Planar micromixer
The present embodiment describes a laminar-mixing embodiment that utilizes simple, three-dimensional injection. Also described is the use of the embodiment in combination with wide and shallow sections of channel to affect rapid mixing in microanalytical systems. The shallow channel sections are constructed using all planar micromachining techniques, including those based on isotropic etching. The planar construction enables design using minimum dispersion concepts that, in turn, enable simultaneous mixing and injection into subsequent chromatography channels.
1. A fluid micromixer, comprising:
a cover portion disposed on a base portion,
wherein said cover portion comprises top and bottom surfaces, a first flow channel disposed in said cover portion bottom surface along a first flow axis, said first flow channel having a uniform width and terminating at first and second ends, said cover portion further comprising a first fluid inlet means disposed along said first flow axis spaced away from said first end and extending through said cover portion, a second flow channel disposed in said cover portion bottom surface along a second flow axis about perpendicular to said first flow axis, said second flow channel having a uniform width and terminating at second and third fluid inlet means extending through said cover portion, said second flow channel crossing and communicating with said first end, and a fluid outlet means extending through said cover portion and intersecting said second end; and
said base portion comprising top and bottom surfaces and a third flow channel disposed in said base portion top surface along a third flow axis and terminating at third and fourth ends, said third flow channel having a uniform width substantially equal to said first flow channel width, wherein said first and third flow axes are substantially coplanar, wherein said second and fourth ends coincide, and wherein said first fluid inlet means intersects said third end.
2. The fluid micromixer of claim 1 , wherein each of said first, second, and third fluid inlet means and said fluid outlet means comprise a portal at said cover portion top surface and a connecting fluid conduit passing through some or all of a thickness of said cover portion.
3. The fluid micromixer of claim 2 , wherein each of said fluid inlet and said fluid outlet portals further comprise a separate fluid reservoir surrounding and communicating with each of said portals.
4. The fluid micromixer of claim 1 , wherein said third flow channel crosses and opens into said second flow channel at said first flow channel first end.
5. The fluid micromixer of claim 2 , wherein each of said fluid conduits comprise a vertical flow channel.
6. The fluid micromixer of claim 1 , wherein said first and second flow channels are either curved or straight.
7. The fluid micromixer of claim 1 , wherein said first and second flow channels are comprised of curved and straight portions.
8. The fluid micromixer of claim 1 , wherein fluid flow is driven by electrokinetic pumping, by pressure pumping, by gravity, or by magnetic fields.
9. The fluid micromixer of claim 8 , wherein convection in said fluid flow is chosen with respect to diffusion.
10. The fluid micromixer of claim 8 , wherein said fluid flow is laminar.
11. The fluid micromixer of claim 1 , wherein said first fluid channel includes 2 or more regions of differing conductance.
12. The fluid micromixer of claim 11 , wherein said of differing conductance comprises regions of different widths and depths.
13. The fluid micromixer of claim 12 , wherein said regions of different widths and depths are arranged to change the flow direction of said fluid.