JP2008296139A - Cleaning method or coating method of passage inwall surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method or a coating method of a passage inwall surface, which enables not only a cleaning of the inwall surface of the passage, but also a coating, by flowing a liquid on the inwall surface of the passage formed in a substrate such as a synthetic resin, glass, and silicone, and adjusting a capillary number (=viscosity×current speed/boundary tension) of the liquid. <P>SOLUTION: The cleaning method of the inwall surface of the passage comprises the step of injecting the liquid to the inwall surface of a passage having an equivalent diameter of 1.5 mm or less and of cleaning the inwall surface of the passage. The cleaning method of the passage inwall surface is characterized in that the inwall surface of the passage is cleaned by adjusting the capillary number (=viscosity×current speed/boundary tension) of the liquid, or the coating method comprises the step of coating the inwall surface of the passage by the same method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, the inner wall surface of the flow path is adjusted by adjusting the number of capillaries (= viscosity × flow velocity / interface tension) of the liquid used when cleaning or coating the inner wall surface of the flow path having an equivalent diameter of 1.5 mm or less. The present invention relates to a cleaning method or a coating method for an inner wall surface of a flow path to be cleaned or applied.

  Conventionally, as a method for cleaning the inner wall surface of a flow channel having a size of less than or equal to millimeter size, a method using a cleaning liquid flowing on the inner wall surface of the flow channel and utilizing a flow shear force or a chemical reaction is used.

  For example, in a flow path after merging in a branch, a cleaning liquid is flowed in the flow path, and vortices generated in a laminar flow, or a flow in a transition region from laminar flow to turbulent flow, or gas is mixed into the cleaning fluid to A method for cleaning the inner wall surface is known. (For example, refer to Patent Document 1).

  Furthermore, a method of cleaning an inner wall surface of a flow path by controlling a micro reactor or a mini reactor with a controlled pressure increase accompanied by a surge of gas pressure using a control device is also known. (For example, refer to Patent Document 2).

Prior art documents are shown below.
JP 2005-501696 A JP 2006-272268 A

  By the way, conventionally, the cleaning method of the inner wall surface of the flow path is a method in which a gas is mixed into the cleaning fluid to clean the inner wall surface of the flow path as described above, or control with a surge of gas pressure using a control device. The cleaning method for the inner wall surface of the flow path is merely a method of cleaning the inner wall surface of the flow path by increasing the applied pressure.

  The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to cause a liquid to flow on the inner wall surface of a flow path formed on a substrate of synthetic resin, glass, silicon, or the like, and the capillary of the liquid The purpose of the present invention is to provide a cleaning method or coating method for the inner wall surface of the flow channel that can be coated as well as cleaning the inner wall surface of the flow channel by adjusting the number (= viscosity × flow velocity / interface tension). To do.

In order to solve the above problems, the invention according to claim 1 of the present invention provides:
A method for cleaning an inner wall surface of a flow channel by injecting a liquid into an inner wall surface of one flow channel having an equivalent diameter of 1.5 mm or less and cleaning the inner wall surface of the flow channel, wherein the number of capillaries of the liquid The flow path inner wall surface cleaning method is characterized in that the inner wall surface of the flow path is cleaned by adjusting (= viscosity × flow velocity / interface tension).

Next, the invention according to claim 2 of the present invention is as follows:
2. The method for cleaning an inner wall surface of a channel according to claim 1, wherein two or more types of liquids injected into the inner wall surface of the channel are not mixed.

Next, the invention according to claim 3 of the present invention is
A method for applying an inner wall surface of a flow channel by injecting a liquid into an inner wall surface of one flow channel having an equivalent diameter of 1.5 mm or less and applying the inner wall surface of the flow channel, wherein the number of capillaries of the liquid The method of applying the inner wall surface of the flow path is characterized in that the inner wall surface of the flow path is applied by adjusting (= viscosity × flow velocity / interface tension).

Next, the invention according to claim 4 of the present invention is
4. The method for coating the inner wall surface of the channel according to claim 3, wherein two or more kinds of liquids injected into the inner wall surface of the channel are not mixed.

  The method for cleaning or coating the inner wall surface of the flow path of the present invention can easily clean or coat the inner wall surface of the flow path by adjusting the number of capillaries of the liquid having the above configuration.

  The cleaning or coating method for the inner wall surface of the flow path of the present invention will be described in detail below along the embodiments.

  In the method for cleaning or applying the inner wall surface of the flow path according to the present invention, before forming the inner wall surface that becomes the flow path, the conditions for cleaning or applying the inner wall surface are obtained in advance by numerical calculation as shown in Example 1 described later. Is preferred.

  At this time, data necessary for the numerical calculation are model shape and size, liquid density, interfacial tension, surface tension, viscosity, liquid volume, contact angle on the inner wall surface of the flow path, boundary conditions, initial conditions, and the like.

  For example, in the case of a silicon substrate or a glass substrate, the inner wall surfaces 4 to 7 of the flow path are formed by a semiconductor microfabrication technique. In the case of a synthetic resin typified by polypropylene or the like, it is produced by thermal transfer or molding.

  Moreover, when inject | pouring two types of connected liquid into the inner wall surfaces 4-7 of a flow path, it is preferable to flow the liquid whose surface tension of the liquid sent ahead is smaller than back. Furthermore, the liquid is preferably a Newtonian fluid.

  The inner wall surfaces 4 to 7 of one channel are washed or applied according to the number of capillaries obtained by the numerical calculation. At this time, if the temperature is constant and the Newtonian fluid is used, the interfacial tension and the viscosity are almost constant, so the number of capillaries is adjusted by changing the flow rate.

  Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

  In the method for cleaning or applying the flow path inner wall surfaces 4 to 7 according to the present invention, it is preferable to obtain the conditions for cleaning or applying in advance by numerical calculation as described above. An example of calculation is shown below.

  In the calculation, as the analysis software, Fluent Inc. Fluent Release 6.2.16 manufactured by the company was used. Data necessary for the numerical calculation includes model shape and size, liquid density, interfacial tension, surface tension, viscosity, liquid amount, contact angle on the flow path surface, boundary conditions, initial conditions, and the like. And this time, temperature is not calculated.

In addition, two immiscible liquids that have not been mixed are allowed to flow through the flow channel as shown in FIG. 1 or FIG. An example of the calculation result of how the liquid flows due to the difference in the number of capillaries at this time is shown below. In addition, the liquid 1 has water physical property values.

<Calculation model, liquid properties and initial conditions are shown below>
-Channel dimension Rectangular cross-sectional shape 1.0 mm (A) x 0.5 mm (B) x 30 mm (C) (shown in FIGS. 1 and 2).
-Physical property value of each liquid Physical property value of liquid 1: density 998 kg / m ³ , viscosity 1.0 mPa · s.
Physical properties of liquid 2: density 840 kg / m ³ , viscosity 24.0 mPa · s.
Liquid quantity liquid 1: 1.5 μL, liquid 2: 3.5 μL.
-Surface tension liquid 1 70.0 mN / m.
Liquid 2 20.0 mN / m.

<Contact angle to air>
Liquid 1 95 ° (all sides), Liquid 2 12 ° (all sides).
The contact angle of the liquid 1 with respect to the liquid 2 is 170 ° (surfaces 1 to 3) and 90 ° (surface 4).
-Interfacial tension between liquid 2 and liquid 1 20 to 50 mN / m.
• Initial conditions and boundary condition conditions are shown in FIG.

<Number of capillaries>
・ The number of capillaries is as follows.
Number of capillaries = η × V / γ
η: viscosity of liquid 2, V: flow velocity, γ: interfacial tension.

  In addition, the calculation was performed by changing the interfacial tension and flow velocity of liquid 1 and liquid 2 as parameters. Then, the conditions for washing or coating the flow path surface were determined by the number of capillaries.

<Conditions for cleaning or application>
-Condition A: When the number of capillaries is 4.8 × 10 ⁻² or more.
The liquid 1 is behind the liquid 2, and the liquid 2 moves while adhering to the wall surface. Therefore, the liquid 2 in front of the liquid 1 decreases as it advances.

<Example of calculation when Condition A>
FIGS. 4 to 6 show calculation examples when the interfacial tension is 50 mN / m, the flow rate is 100 mm / s, and the number of capillaries is 4.8 × 10 ⁻² . Moreover, when a cross-sectional view is seen as shown in FIG. 6, two passages are formed on the top. The liquid 2 proceeds from this passage while adhering to the wall surface.
Condition B: When the number of capillaries is less than 2.8 × 10 ⁻² .
Liquid 1 travels connected without passing over liquid 2.

<Calculation example for condition B>
7 to 9 show the calculation results when the interfacial tension is 20 mN / m, the flow rate is 4.44 mm / s, the number of capillaries is 5.328 × 10 ⁻³ , and the two connected liquids travel to the vicinity of the outlet. When the cross section of FIG. 9 is seen unlike the condition A, the liquid 2 does not go to the rear even if it goes through the flow path where the passage is not possible, and hardly goes to the surface of the flow path.

<Calculation result>
From this calculation result, the condition is that the flow path surface is applied when the condition A is satisfied and the flow path surface is cleaned when the condition B is satisfied. Further, if the temperature is constant and the Newtonian fluid is used, the interfacial tension and viscosity are almost constant. Therefore, the number of capillaries can be adjusted by changing the flow rate, and the inner wall surface of the flow path can be washed or applied.

It is sectional drawing which shows the cross section of one Example of the flow-path inner wall surface of the washing | cleaning or application | coating method of the flow-path inner wall surface of this invention. It is the schematic which shows the outline of one Example of the flow path of the washing | cleaning or application | coating method of the flow-path inner wall surface of this invention. It is the schematic for demonstrating one Example of the calculation initial state and boundary condition of the washing | cleaning or application | coating method of the flow-path inner wall surface of this invention. Explanatory drawing for demonstrating the conditions according to calculation etc. when apply | coating the inner wall surface of the flow path of the coating method of the inner surface of a flow path of this invention (at the time of interface tension 50mN / m, flow velocity 100mm / s, 0.17169s) The calculation result is 1). Other explanatory views (interfacial tension of 50 mN / m, flow velocity of 100 mm / s, 0.17169 s) for explaining calculation-specific conditions when applying the inner wall surface of the flow channel in the coating method of the inner wall surface of the flow channel of the present invention. This is the result of calculation 2). Other explanatory views for explaining calculation-specific conditions when applying the inner wall surface of the flow channel in the flow channel inner wall surface coating method of the present invention (interfacial tension 50 mN / m, flow velocity 100 mm / s, 0.17169 s) (Cross-sectional view of the flow path). Still another explanatory diagram for explaining the calculation-specific conditions when the inner wall surface of the flow path of the flow path inner wall surface cleaning method of the present invention is cleaned (interfacial tension 20 mN / m, flow velocity 4.44 mm / s, The calculation result at the time of 2.0012s is 1). Still another explanatory view for explaining the conditions according to calculation when cleaning the inner wall surface of the flow path in the cleaning method of the inner wall surface of the flow path of the present invention (interfacial tension 20 mN / m, flow velocity 4.44 mm / s, 2. Calculation results for 0012s (2) Other explanatory views for explaining the calculation-specific conditions when cleaning the inner wall surface of the flow path in the flow path inner wall surface cleaning method of the present invention (interfacial tension 20 mN / m, flow velocity 4.44 mm / s, 2 . Section of the channel at the time of.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Liquid 2 ... Liquid 3 ... Air 4 ... Surface 1
5 ... Surface 2
6 ... surface 3
7 ... Surface 4
A ... Width (1mm)
B ... Height (0.5mm)
C ... Length (30mm)
D ... Liquid 1 (3mm)
E ... Liquid 2 (7mm)

Claims (4)

  A method for cleaning an inner wall surface of a flow channel by injecting a liquid into an inner wall surface of one flow channel having an equivalent diameter of 1.5 mm or less and cleaning the inner wall surface of the flow channel, wherein the number of capillaries of the liquid A method for cleaning an inner wall surface of a flow path, wherein the inner wall surface of the flow path is cleaned by adjusting (= viscosity × flow velocity / interface tension).   2. The method for cleaning an inner wall surface of a channel according to claim 1, wherein two or more kinds of liquids that are not mixed are connected to the inner wall surface of the channel.   A method for applying an inner wall surface of a flow channel by injecting a liquid into an inner wall surface of one flow channel having an equivalent diameter of 1.5 mm or less and applying the inner wall surface of the flow channel, wherein the number of capillaries of the liquid A method for applying an inner wall surface of a channel, wherein the inner wall surface of the channel is applied by adjusting (= viscosity × flow velocity / interface tension).   The method for applying an inner wall surface of a flow path according to claim 3, wherein two or more kinds of liquids that are not mixed are connected to the inner wall surface of the flow path.

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