JP3888275B2 - Micro mixer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a micromixer that stirs and mixes a minute volume of gas, liquid, or solid using a minute flow path formed on a substrate.
[0002]
[Prior art]
In recent years, microchannels have been created on substrates such as silicon, glass, and plastic using micromachining technology, and the microspace can be used for mixing various solutions, chemical reactions, analysis, etc. Attempts are attracting attention. Devices and apparatuses used in these fields are called micromixers and microreactors depending on the purpose of use.
[0003]
In such a micromixer, those having a reaction channel equivalent diameter (diameter when the cross section of the channel is converted into a circle) of less than 500 μm are usually defined as microchannels (microchannels). As described above, when the scale of the flow path becomes smaller, (1) since the Reynolds number becomes smaller, the flow becomes laminar, and (2) the surface area per unit volume becomes very large. It is done.
[0004]
This feature increases the gradient of temperature, pressure, concentration, etc., improving the efficiency of heat conduction, mass transfer diffusion, etc., and gaining advantages such as shortening the reaction time in the reaction system and improving the reaction rate become. Furthermore, since it is possible to synthesize an appropriate amount by a minute reaction and to obtain high reproducibility, the amount of chemicals and catalyst reagents used can be greatly reduced, which is economically effective.
[0005]
The following various planar structures have been proposed as conventional techniques related to the structure of such a micromixer (see, for example, Non-Patent Documents 1 to 3).
[0006]
First, a micromixer called Y-type as shown in FIGS. 3 and 4 is known. FIG. 3 is a diagram illustrating each component of an example of a Y-type micromixer, and is a plan view of (A) a cover plate and (B) a substrate, and FIG. 4 is a plan view of the substrate and cover plate of FIG. It is sectional drawing along CC 'arrow line after joining.
[0007]
The micromixer 50 includes a cover plate 51 and a substrate 52. As shown in FIG. 3B, a Y-shaped microchannel 56 is formed in the substrate 52. Further, as shown in FIG. 3A, the lid plate 51 is supplied with various solutions, chemicals, reagents and the like to the microchannel 56 at positions communicating with both ends of the Y-shaped microchannel 56. The supply ports 53 and 54 are provided, and an outlet 55 for taking out the mixed or reacted fluid is formed at a position communicating with the tip of the Y-shaped microchannel 56 after the merge. .
[0008]
Then, as shown in FIG. 4, the lid plate 51 and the substrate 52 are joined, and various fluids supplied from the supply ports 53 and 54 are mixed in the microchannel 56 and can be taken out from the outlet 55. Thus, a continuous flow path is formed.
[0009]
In addition, a micromixer called a T type using a substrate 60 on which a T-shaped microchannel 61 is formed as shown in FIG. 5 instead of the substrate 52 is also known.
[0010]
In the micro flow channel having an equivalent diameter of 500 μm or less as described above, the Reynolds number is as small as about 10 to several 100, so the flow is in a laminar flow state. Therefore, in the Y-type or T-type micromixer as described above, the solution supplied from the two supply ports 53 and 54 becomes a two-layer flow in the microchannel, and the stirring and mixing of the two layers is diffusion. Being controlled, complete mixing requires a certain amount of time.
[0011]
Therefore, in order to shorten the mixing time, it has also been proposed to divide the two-layer flow into a large number on a plane to create a large number of laminar flows to increase the mixing and stirring efficiency.
[0012]
FIG. 6 shows an example of such a substrate. Instead of the above-described substrates 52 and 60, a substrate 70 in which a multi-channel 71 that creates a plurality of laminar flows by dividing a flow of two layers into a number of layers is formed. Used. By using the multi-channel 71, the fluid introduced from the two supply ports 53 and 54 is divided into a large number of laminar flows in the multi-channel 71, thereby improving the stirring and mixing efficiency. .
[0013]
In addition, as another conventional technique related to the structure of a micromixer, for example, a large number of biochemical reactions of 1000 or more can be performed simultaneously in parallel, and not only simple analysis but also a substance synthesis reaction such as protein synthesis can be performed. As a microreactor for biochemical reaction that can be performed on a cell, a plurality of independent reaction chambers formed by anisotropic etching on the surface of a silicon substrate and anodically bonded to the surface of the silicon substrate to seal the reaction chamber A microreactor comprising a flat plate is disclosed (see Patent Document 1).
[0014]
[Non-Patent Document 1]
B. He, N .; Tait, F.A. Regnier: Anal. Chem. 70, 3790 (1998)
[Non-Patent Document 2]
W. Ehrfeld, V.E. Hessel, H.C. Low: Microreactors. , PP64-66, Wille VHC (2000)
[Non-Patent Document 3]
Grass wall, outer ring, Morooka: Trends in microreactor research and application to thermochemistry. Instrumentation, Vol. 45, No. 1 (2002)
[Patent Document 1]
Japanese Patent Laid-Open No. 10-337173
[Problems to be solved by the invention]
In any of the above-described conventional micromixers, usually, silicon or glass is used as a substrate, a minute flow pattern is formed on the substrate by a method such as dry plasma etching or wet etching, and a lid plate is formed. Joined and bonded. Therefore, all of the microchannels used for mixing are arranged in a plane.
[0016]
As described above, since the fluid in the microchannel formed in a plane is a laminar flow, stirring and mixing are governed by diffusion. For this reason, in order to increase the mixing efficiency in the laminar flow state, it is necessary to divide the flow into several to create a large number of laminar flows, and a multi-channel as shown in FIG. 6 is required.
[0017]
However, even in the above-described multi-channel, there is a problem that the efficiency is low because the fluid is a laminar flow and stirring and mixing are governed by diffusion because it is a microchannel formed in a plane.
[0018]
In addition, when the multi-channel is formed on a plane, there is a problem that the substrate area becomes large and it becomes difficult to miniaturize the apparatus / device. This means that there are not two types of solutions for mixing. , Especially in the case of multi-component systems.
[0019]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a micromixer with improved stirring efficiency and mixing efficiency by combining the flow directions while maintaining the miniaturization required for the micromixer. And
[0020]
[Means for Solving the Problems]
In order to solve the above problems, a micro mixer of the present invention, a plurality of supply ports for introducing a plurality of fluids to be mixed, and one or more outlet for taking out the mixed fluid is provided A lid plate;
A vertical flow path substrate in which a first vertical communication path communicating with the supply port and a fluid reservoir chamber communicating with the outlet are formed;
A horizontal flow path substrate in which a second vertical communication path communicating with the first vertical communication path and a horizontal micro flow path communicating with the fluid reservoir chamber are formed;
A bottom plate formed with a groove-shaped microchannel communicating with the second vertical communication channel and the horizontal microchannel is at least laminated;
From the supply port of the lid plate, the outlet of the lid plate is passed through the first vertical communication passage, the second vertical communication passage, the groove-like micro flow channel, the horizontal micro flow channel, and the fluid reservoir chamber. A continuous flow path communicating with is formed ,
The horizontal microchannels of the horizontal channel substrate are arranged radially, and the groove-like microchannels of the bottom plate are annular so as to communicate with the radial horizontal microchannels. .
[0021]
According to this, the fluids injected vertically from the respective supply ports become parallel flows in the groove-like micro-channels on the bottom plate, and the parallel flows flow into the horizontal channel substrate vertically and then again in parallel. It is converted into a flow, which is further taken out as a vertical flow. In this way, since there is a flow change over several orders, the contact interface area of different fluids becomes large and the degree of mixing is improved, and further turbulent flow occurs when changing from vertical flow to parallel flow and from parallel flow to vertical flow. Therefore, the degree of mixing is further improved by the turbulent flow effect.
[0023]
In further, by arranging the horizontal fine channel radially, as compared to the micro-mixer arranged fine channel in a plate shape, it can be reduced the area occupied by the micro-mixer, the miniaturization of the micromixer, thinned, and Then, an array as a mixing device can be realized.
[0024]
In the present invention, it is preferable that the lid plate, the bottom plate, the horizontal flow path substrate, and the vertical flow path substrate are integrated and laminated by diffusion bonding.
[0025]
This eliminates the need for an adhesive or the like during bonding by diffusion bonding, and thus can effectively prevent chemical reaction and contamination with the sample solution, and each plate material with sufficient bonding strength. Can be integrated and stacked.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail. 1 and 2 show an embodiment of the micromixer of the present invention. FIG. 1 is an exploded perspective view showing an embodiment of the micromixer of the present invention, and FIG. 2 is a cross-sectional view taken along the line DD ′ after FIG.
[0027]
As shown in FIGS. 1 and 2, the micromixer 100 includes a cover plate 10 for introducing and removing a plurality of fluids to be mixed, and a bottom plate 40 for receiving the mixed fluid and diffusing it circumferentially. The vertical flow path substrate 20 and the horizontal flow path substrate 30 are stacked and integrated in order.
[0028]
The cover plate 10 is provided with a plurality of supply ports 11 and 12 for supplying fluid as through holes near both ends thereof. In addition, an outlet 13 for taking out the mixed fluid is provided at the center of the lid plate 10.
[0029]
The material of the lid plate 10 is not particularly limited, and a conventionally known material made of metal, silicon, glass, plastic, or the like can be used. However, it is excellent in chemical resistance and stable, and easily by diffusion bonding as described later. It is preferable to use a metal because it is a material that can be joined to each other and a number of supply ports can be easily formed. As the metal, for example, metals such as copper, iron, aluminum, nickel, titanium, niobium, zirconium, molybdenum, tungsten, or alloys thereof can be used, and the purpose and conditions of use of the micromixer (with solutions and chemicals) It is selected based on the presence or absence of chemical reaction, temperature / environment at the time of use, etc., but it is easy to form a micro flow path by etching, etc., it is excellent in processing accuracy, and also has chemical resistance and heat resistance to solutions and chemicals. It is preferable to use a stainless steel foil or a thin plate from the viewpoints of properties and economics of materials.
[0030]
In addition, when chemical stability against various solutions and chemicals is more important, metals such as titanium, niobium and nickel or alloys thereof, and when intended for use at higher temperatures, molybdenum, tungsten or It is preferable to use the alloy.
[0031]
The thickness of the lid plate 10 is not particularly limited, but preferably 10 to 500 μm.
[0032]
The supply ports 11 and 12 and the outlet 13 are appropriately formed at predetermined positions according to the shape of the flow path. The number of supply ports and outlets can be appropriately selected according to the number of fluids to be mixed and is not limited. The supply ports 11 and 12 and the outlet 13 can be formed by, for example, wet etching, drilling, ultrasonic machining, electric discharge machining, punch punching, or the like.
[0033]
A vertical flow path substrate 20 is bonded to the lower surface of the lid member 10. As shown in FIG. 1, first vertical communication passages 21 and 22 are formed through the vertical flow path substrate 20 at positions that communicate with the supply ports 11 and 12 of the lid member 10. A fluid reservoir chamber 23 is formed in a circular shape at a position communicating with the outlet 13 of the lid member 10.
[0034]
The material and thickness of the vertical flow path substrate 20, the first vertical communication paths 21 and 22, the formation method of the fluid reservoir 23, and the like can be the same as those for the cover plate 10.
[0035]
Further, a horizontal flow path substrate 30 is bonded to the lower surface of the vertical flow path substrate 20. At both ends of the horizontal flow path substrate 30, second vertical communication paths 31 and 32 are formed at positions communicating with the first vertical communication paths 21 and 22 of the vertical flow path substrate 20.
[0036]
Further, a circular merging portion 33 is formed through the central portion of the horizontal flow path substrate 30 at a position communicating with the fluid reservoir chamber 23 of the vertical flow path substrate 20, and further radially from the merging portion 33. Extending radial microchannels 34 are formed. In this embodiment, eight radial microchannels 34 are formed from the merging portion 33, and turbulence is generated near the central portion of each radial microchannel 34 to improve the agitation and mixing rate. A bulging portion 35 is provided for this purpose.
[0037]
The shape, length, and number of the radial microchannels 34 are not particularly limited and can be selected as appropriate. For example, the shape of the radial microchannel 34 is not limited to the linear shape as shown in FIG. 1, but may be S-shaped or zigzag-shaped. The width of the microchannel is not particularly limited, but is preferably 10 to 500 μm. If the width of the micro flow path is less than 10 μm, the flow path is likely to be blocked, which is not preferable, and if it exceeds 500 μm, the diffusion time required for mixing becomes long.
[0038]
The material and thickness of the horizontal flow path substrate 30, the formation method of the micro flow path, and the like can be the same as those for the cover plate 10.
[0039]
In the present invention, the horizontal microchannels formed in the horizontal channel substrate 30 are not necessarily limited to the radial shape as described above, and may be, for example, a comb shape.
[0040]
Further, a bottom plate 40 is joined to the lower surface of the horizontal flow path substrate 30. As shown in FIG. 1, a circular groove 41 is formed on the bottom plate 40 at a position communicating with the end of the radial microchannel 34 of the horizontal channel substrate 30. Two linear grooves 42 extending toward both ends of the bottom plate 40 are formed continuously, and the ends of the linear grooves 42 communicate with the communication channels 31 and 32 of the horizontal channel substrate 30. Is formed.
[0041]
As the forming method of the annular groove 41 and the linear groove 42, it can be formed by a conventionally known fine plasma processing such as dry plasma etching or wet etching using a hydrofluoric acid solution. The sizes of the annular groove 41 and the linear groove 42 can be appropriately set and are not limited. However, it is usually preferable that the width is 500 μm or less and the depth is about several tens of μm.
[0042]
Further, in the present invention, the groove-like microchannel formed in the bottom plate 40 only needs to communicate with the second vertical communication channel and the horizontal microchannel. The combination with the groove 42 is not necessarily limited.
[0043]
Each of the above substrates is joined and integrated by a conventionally known method. Examples of the bonding method include a method of bonding with an organic adhesive such as an epoxy resin, a method of bonding using a bonding material such as solder and silver solder, and a heat treatment of a solution mainly containing a fluorine-based resin. Can be used, such as a method of bonding a fluorine-based resin layer as an adhesive layer, a method of bonding a metal oxide layer formed by heat treatment of a hydrolyzed / dehydrated condensation product of an organometallic compound as an adhesive layer, diffusion bonding, etc. Of these, it is preferable to use diffusion bonding.
[0044]
Diffusion bonding is a method of direct bonding using diffusion between metals by heating and pressurizing under vacuum, and since no adhesive or bonding layer is used, even if there is a mismatch in bonding conditions, There is no blockage. In addition, leakage between the microchannels due to the nonuniformity of the bonding layer can be prevented. Furthermore, it is excellent in chemical resistance and heat resistance to various solvent chemicals and reagents.
[0045]
Diffusion bonding can be performed by a conventionally known diffusion bonding apparatus. The conditions for diffusion bonding are appropriately selected depending on the bonding material. For example, in the case of stainless steel, the heating temperature is 750 to 1000 ° C., the load is 0.1 to 1.0 kg / mm ² , and the degree of vacuum is 10 ⁻⁴ torr or less. The holding time is preferably 1 to 5 hours.
[0046]
As shown in FIG. 2, the micromixer 100 thus obtained has a linear groove on the bottom plate 40 from the supply ports 11 and 12 through the first communication passages 21 and 22 and the second communication passages 31 and 31. 42 and 43 communicate with the annular groove 41. Further, the annular groove 41 communicates with the end of the radial microchannel 34 of the horizontal channel substrate 30, and finally communicates with the outlet 13 through the central junction 33 and the fluid reservoir 23. A continuous flow path is formed.
[0047]
In the present invention, the number of the vertical flow path substrates 20 and the horizontal flow path substrates 30 provided between the cover plate 10 and the bottom plate 40 is not limited, and may be provided one by one as in this embodiment. A plurality of sheets may be provided. As described above, by alternately flowing the fluid in the horizontal direction and the vertical direction, the change (turn) of the flow of the fluid is increased, so that the mixing efficiency is further improved. Moreover, since the length of the continuous flow path can be increased, the length of the micro flow path per sheet can be shortened. Therefore, the micromixer can be downsized without reducing the mixing efficiency.
[0048]
Further, the substrate area of the micromixer 100 is appropriately set according to the width and number of horizontal microchannels formed on the horizontal channel substrate 30.
[0049]
The micromixer 100 is used as follows, for example.
First, a plurality of sample fluids to be mixed are injected into the supply ports 11 and 12 by a sample fluid supply means (not shown). As the plurality of sample fluids, liquid, gas, fine solid, or a combination thereof can be applied, and is not particularly limited to a solution. In addition, the sample fluid may be supplied using gravity and capillary action, or may be pressurized and injected by a microsyringe pump or the like, but in the present invention, the fluid once forms a linear groove on the bottom plate 40. 41, since it descends to the annular groove 40 and then rises to the outlet 13 of the lid plate 10, it is preferable to inject pressure from the supply ports 11 and 12 by a dispenser, a microsyringe or the like.
[0050]
Each sample solution reaches the end of the linear grooves 42 and 43 of the bottom plate 40 via the first communication passages 21 and 22 and the second communication passages 31 and 31, and then reaches the annular groove 41 to be stirred. Mixing is started.
[0051]
Thereafter, the mixed fluid rises to the end of the radial microchannel 34 of the horizontal channel substrate 30 communicating with the annular groove 41, and further reaches the junction 33. Here, the mixed fluid becomes a laminar flow, and further mixing is performed by diffusion. In addition, since the bulging part 35 is formed in each radial microchannel 34, a mixing degree improves more by generating a turbulent flow here.
[0052]
The fluid mixed in the plurality of radial microchannels 34 reaches the fluid reservoir chamber 23 of the vertical channel substrate 20 from the merging portion 33 and is further rectified in the fluid reservoir chamber 23, and then provided on the lid plate 10. A series of mixing steps are completed by taking out from the outlet 13 to the outside.
[0053]
According to the micromixer 100, fluids injected vertically from the respective supply ports 11 and 12 become parallel flows in the linear grooves 41 and 42 and the annular groove 43 of the bottom plate 40, and these parallel flows are converted into horizontal flow paths. After vertically flowing into the substrate, it is converted again into a parallel flow, which is further taken out as a vertical flow. As described above, in this micromixer 100, since the flow is changed over several orders, the contact interface area of different fluids is increased, the degree of mixing is improved, and further, the vertical flow to the parallel flow, and the parallel flow to the vertical flow. Since the turbulent flow is also generated when changing to, the mixing degree is further improved by the turbulent flow effect.
[0054]
Furthermore, by arranging the horizontal microchannels radially, the area occupied by the micromixer can be reduced and made thinner compared to the micromixer in which the microchannels are arranged on the flat surface in the prior art described above. Since the black mixer can be reduced in size, an array as a mixing device can be easily performed.
[0055]
In the above mixing, in order to control and monitor the mixing conditions, a heater device, an analysis device for monitoring the mixing state, and the like may be attached to the micro remixer according to the purpose.
[0056]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
[0057]
<Formation of each substrate>
A lid plate 10, a vertical flow path substrate 20, a horizontal flow path substrate 30, and a bottom plate 40 were formed in the shape shown in FIG. Further, the supply port, the outlet, the minute flow path, and the like in each substrate were formed through by wet etching using aqua regia. In addition, all the magnitude | sizes of said each board | substrate were 20x30 mm.
A stainless steel thin plate having a thickness of 0.2 mm was used as the cover plate 10, and through holes having a hole diameter of 0.5 mm were formed as the supply ports 11 and 12.
As the vertical flow path substrate 20, a stainless thin plate having a thickness of 0.5 mm is used, a through hole having a hole diameter of 0.3 mm is used as the first communication passages 21 and 22, and a through hole having a hole diameter of 0.8 mm is used as the fluid reservoir chamber 23. Formed.
As the horizontal flow path substrate 30, a stainless steel plate having a thickness of 0.2 mm was used, and through holes having a hole diameter of 0.3 mm were formed as the second communication paths 21 and 22. In addition, as the horizontal microchannels, the eight radial microchannels 34 are set so that each radial microchannel 34 has a length of 5 mm, a width of 0.08 mm, and a maximum width of the bulging portion 35 of 0.15 mm. Formed.
As the bottom plate 40, a stainless steel plate having a thickness of 0.5 mm was used, and an annular groove 41 and a linear groove 42 having a diameter of 10 mm were formed with a channel width of 0.15 mm and a depth of 0.15 mm.
[0058]
<Bonding of each substrate>
Each of the above substrates was sequentially laminated as shown in FIG. 2 and joined by diffusion bonding to obtain a micromixer 100 of an example having a total thickness of 1.4 mm.
The diffusion bonding was carried out by applying a load of 0.1 kg / mm ² , and holding at 950 ° C. for 1 hour in a vacuum atmosphere of 1 × 10 ⁻⁴ torr or less for integration.
[0059]
In the micromixer 100 of the above embodiment, a continuous flow path from the supply ports 11 and 12 of the cover plate 10 to the take-out port 13 is formed by X-ray imaging, ultrasonic flaw detection, and the like as shown in FIG. It was confirmed that it was formed.
[0060]
Each substrate was completely integrated, and no leakage of solution at the bonding interface was observed.
[0061]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a micromixer with improved stirring efficiency and mixing efficiency by combining the flow directions while maintaining the miniaturization required for the micromixer.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an embodiment of a microchannel chip of the present invention.
2 is a cross-sectional view taken along the line DD ′ after joining in FIG. 1. FIG.
FIGS. 3A and 3B are diagrams showing components constituting an example of a conventional micromixer, and are plan views of (A) a cover plate and (B) a substrate.
4 is a cross-sectional view taken along the line CC ′ after joining the substrate and the cover plate of FIG. 3;
FIG. 5 is a plan view showing another example of a substrate in a conventional micromixer.
FIG. 6 is a plan view showing still another example of a substrate in a conventional micromixer.
[Explanation of symbols]
10: lid plate 11, 12: supply port 13: outlet 20: vertical flow path substrate 21, 22: first vertical communication path 23: fluid reservoir 30: horizontal flow path substrate 31, 32: second communication path 33: Junction 34: Radial microchannel 35: Swelling 40: Bottom plate 41: Circular groove 42: Linear groove 100: Micromixer

Claims (2)

A plurality of the plurality of supply ports for introducing the fluid, and 1 for taking out a mixed fluid or preparative cover plate which outlet is provided to be mixed,
A vertical channel substrate in which a first vertical communication path communicating with the supply port and a fluid reservoir chamber communicating with the take-out port are formed;
A horizontal flow path substrate in which a second vertical communication path communicating with the first vertical communication path and a horizontal micro flow path communicating with the fluid reservoir chamber are formed;
A bottom plate on which a groove-like micro flow channel communicating with the second vertical communication channel and the horizontal micro flow channel is formed is laminated;
From the supply port of the lid plate, the outlet of the lid plate is passed through the first vertical communication passage, the second vertical communication passage, the groove-like microchannel, the horizontal microchannel, and the fluid reservoir chamber. A continuous flow path communicating with is formed ,
The horizontal microchannels of the horizontal channel substrate are arranged radially, and the groove-like microchannels of the bottom plate are annular so as to communicate with the radial horizontal microchannels. Micro mixer. The cover plate, a bottom plate, horizontal flow path substrate, and micro-mixer according to claim 1, wherein the vertical flow path substrate are stacked is integrated by diffusion bonding.

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