KR20070061109A - Thermopneumatic microvalve with membrane - Google Patents

Abstract

A thermo-pneumatic micro valve with a membrane is provided to be applied for pumping liquid in a flow control chamber in a predetermined direction through a continuous heating and cooling. A thermo-pneumatic micro valve with a membrane includes a plurality of channels, a flow control chamber(102), a pressure control chamber(107), a pair of temperature control units(105,106), and a membrane(101). The channels are connected with the flow control chamber. The flow control chamber controls the flow and an amount of the fluid in the channels. The pressure control chamber is wrapped by a side wall formed in a second substrate, a top of which is wrapped by the membrane, a bottom of which is wrapped by a temperature control substrate(108). The temperature control unit controls a temperature of a medium of the pressure control chamber. The membrane controls the flow of the fluid of the channels.

Description

Thermopneumatic microvalve with membrane

1 is a cross-sectional view showing a thermopneumatic microvalve according to an embodiment of the present invention.

2 is an exploded perspective view illustrating a thermopneumatic microvalve according to an embodiment of the present invention.

3A and 3B are cross-sectional views illustrating a valve operation according to the shape change of the membrane shown in FIG. 1.

4A and 4B are cross-sectional views and diagrams for describing flow rate control according to the shape change of the membrane shown in FIG. 1.

5A-5D are some cross-sectional views illustrating various shapes of the flow control chamber.

6 is a conceptual diagram illustrating the membrane fixing by bonding applied to an embodiment of the present invention.

7 is a partial plan view illustrating various types of combinations of flow control chamber and membrane chamber.

The present invention relates to a thermopneumatic microvalve, and more particularly to a thermopneumatic microvalve that can be applied to microfluidic devices used in biochips and lab-on-a-chips.

In general, biochips for biochemical analysis such as DNA chips or protein chips, and lab-on-a-chip using microfluidic control techniques, can be used to stop, flow, pump, mix, distribute, and Flow control techniques such as separation are required, and various control schemes have been proposed for this purpose.

It is a microvalve that plays a role of stopping the microfluid and adjusting the flow rate, and performing the pumping of the microfluid is collectively called a micropump. The microvalve and the micropump are interconnected with their driving methods, and various types of microvalve and pump have been proposed.

For example, electro-hydraulic methods such as a micro-actuating method, an electrophoretic method, and an electroosmotic method using a mechanical pneumatic method and a piezoelectric effect (PZT) as the driving method of the micro pump and the valve. Electro-hydrodynamic (EHD) driving method, driving method using electrochemical reaction, driving method using the change of thermal optical and electrical properties of paraffin, gel, porous puller or beads, capillary flow method by surface tension ( Capillary flow method (SAW), surface acoustic wave (SAW) driving method, volumetric force controlled driving method using centrifugal force or Coriolis force, and driving method using thermal, electrical charge or optical surface material property change .

As described above, various micropumps and valves have been proposed by various driving methods. However, the driving methods, manufacturing and control are complicated, expensive materials such as silicon, and driving flow rate and pressure are often limited. .

Accordingly, there is a need for a simple and inexpensive high performance micropump and microvalve that overcomes these drawbacks. In particular, in the case of biochips and lab-on-a-chips, as the degree of directness increases, the number of chambers and channels that perform various functions increases, and accordingly, the number of microvalvees to be directly increased increases the complexity of driving control and becomes expensive. Therefore, when using the existing method is not suitable for one-time use occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a low-cost microvalve capable of controlling the flow of a fluid and its flow rate in a simple driving manner.

The invention provides channels for flowing a fluid; A flow control chamber connecting the channels; A pressure control chamber comprising a medium in which the volume expands with temperature change; A temperature controller for controlling the temperature of the medium of the pressure control chamber; And a membrane for dividing the flow control chamber and the pressure control chamber and controlling the fluid flow of the channels by elastically deforming to occupy the flow control chamber when the pressure in the pressure control chamber increases. to provide.

The thermopneumatic microvalve may further comprise an inlet and an outlet of the fluid connected to the channels.

The side wall of the pressure control chamber may be formed of a material having a low heat transfer coefficient.

The pressure control chamber may have the form of a truncated cone or a truncated cone.

The medium may be air.

The medium comprises a gas comprising nitrogen, oxygen, carbon dioxide and helium; Liquids including water, alcohols, acetone and mercury; And solid materials including paraffins, gels, polymers and porous materials.

Sidewalls forming the flow control chamber and the pressure control chamber may be formed of plastic without elastic deformation.

The cross section of the flow control chamber and the cross section of the pressure control chamber in contact with the membrane may have the same shape.

The temperature control unit may include a heater and a temperature sensor.

The membrane may be one capable of elastic deformation and restoration without permeating gas and liquid.

The membrane may be formed of a material selected from the group consisting of silicone rubber, latex film and PDMS film.

The invention includes a first substrate having channels for flowing fluid and a flow control chamber connecting the channels; A second substrate having a sidewall and a membrane chamber of a pressure control chamber including a medium in which volume expands with a temperature change and bonded to the first substrate; A membrane formed in at least a portion of the membrane chamber to divide the flow control chamber and the pressure control chamber and to elastically deform to occupy the flow control chamber when the pressure in the pressure control chamber increases to control the fluid flow of the channels; And a temperature control substrate including a heater and a temperature sensor to control the temperature of the medium of the pressure control chamber and forming one surface of the pressure control chamber.

The first substrate and the second substrate may be formed of plastic without elastic deformation.

Bonding of the first substrate and the second substrate may be performed by hot pressure bonding, adhesive bonding, or ultrasonic bonding.

The thickness of the membrane is greater than the depth of the membrane chamber and upon bonding of the first substrate and the second substrate the membrane may be partially compressed and fixed.

The cross section abutting the membrane of the pressure control chamber coincides with the cross section of the flow control chamber and the cross section facing the membrane may have a truncated cone or pyramid shape corresponding to the area of the heater.

The medium may be air.

The medium comprises a gas comprising nitrogen, oxygen, carbon dioxide and helium; Liquids including water, alcohols, acetone and mercury; And solid materials including paraffins, gels, polymers and porous materials.

The membrane may be one capable of elastic deformation and restoration without permeating gas and liquid.

The membrane may be formed of a material selected from the group consisting of silicone rubber, latex film and PDMS film.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

1 is a cross-sectional view showing a thermopneumatic microvalve according to an embodiment of the present invention.

Referring to FIG. 1, a thermopneumatic microvalve according to an embodiment of the present invention includes channels, a flow control chamber 102, a pressure control chamber 107, a temperature controller 105 and 106, and a membrane 101. do.

The channels serve as passageways for flowing fluid and are connected to the flow control chamber 102. In FIG. 1, the channels are not shown as they are formed perpendicular to the cross section of the flow control chamber 102. The channels are formed on the first substrate 103.

The flow control chamber 102 connects the channels and functions to control the flow and the flow rate of the fluid flowing through the channels. The sidewalls forming the flow control chamber 102 are preferably formed of plastic without elastic deformation. The flow control chamber 102 is formed on the first substrate 103. The flow control chamber 102 is surrounded by a first substrate 103 and a membrane 101.

The pressure control chamber 107 is surrounded by sidewalls formed in the second substrate 104, surrounded by a membrane 101 at the top and a temperature controlled substrate 108 at the bottom. The sidewalls forming the pressure control chamber 107 are preferably formed of a material, such as a plastic, having no elastic deformation and a low heat transfer coefficient.

The pressure control chamber 107 includes a medium in which the volume expands as the temperature changes. The medium may be air, together with or independently of the air, a gas comprising nitrogen, oxygen, carbon dioxide and helium; Liquids including water, alcohols, acetone and mercury; And solid materials including paraffins, gels, polymers, and porous materials.

The pressure control chamber 107 is formed such that one side having a hole is located at the center of the flow control chamber 102 on the first substrate 103, and the opposite side corresponds to the heater 105 of the temperature control substrate. . In consideration of the heating temperature and the thickness of the second substrate 104, it is preferable to form a tapered shape, that is, a truncated cone or a truncated pyramid in the thickness direction so that the volume can be adjusted according to the air expansion rate.

The cross section of the flow control chamber 102 and the cross section of the pressure control chamber 107 in contact with the membrane 101 preferably correspond to have the same shape.

The sidewalls forming the flow control chamber 102 and the pressure control chamber 107, ie the first substrate 103 and the second substrate 104, are preferably formed of plastic, in particular rigid plastic plastic. The plastic may be, for example, polymethylmethacrylate (PMMA), polycarbonate (PC), cycloolefin copolymer (COC), polyamide (PA), polyethylene (PE, PE), Polypropylene (PP), polyphenylene ether (PPE), polystyrene (PS), polyoxymethylene (POM), polyetheretherketone (PEEK), polytetraproethylene (polytetrafluoroethylene, PTFE), polyvinylchloride (PVC), polyvinylidene fluoride (PVDF), polybutyleneterephthalate (PBT), fluorinated ethylenepropylene (FEP) or perflow It may be perfluoralkoxyalkane (PFA).

The temperature control unit controls the temperature of the medium of the pressure control chamber 107. The temperature control unit includes a heater 105 and a temperature sensor 106 formed on the temperature control substrate 108.

The membrane 101 divides the flow control chamber 102 and the pressure control chamber 107 and elastically deforms when the pressure of the pressure control chamber 107 increases to occupy the flow control chamber 102. Control their fluid flow.

The membrane 101 is made of a material that is elastically deformable and recoverable without permeating gas and liquid such as air, such as silicone rubber, latex film, and PDMS film, and includes a flow control chamber ( It is desirable to have a larger area than 102 and to be formed in the membrane chamber 109 of the second substrate 104. On the other hand, the membrane 101 may be manufactured by spin coating, punching or laser cutting.

2 is an exploded perspective view illustrating a thermopneumatic microvalve according to an embodiment of the present invention.

Referring to FIG. 2, the thermopneumatic microvalve is composed of a first substrate 203, a membrane 201, a second substrate 204, and a temperature control substrate 208. The first substrate 203 has channels 212 for flowing a fluid, a flow control chamber 202 connecting the channels, and an inlet 211 and an outlet 212 connected to the channels. Each of the above elements may be formed by drilling by an NC machine or a laser. The inlet 211 and the outlet 212 may be formed in plurality, depending on the purpose, if necessary through the second substrate 204 and the temperature control substrate 208 instead of the first substrate 203. have.

The second substrate 204 is formed with a sidewall of the pressure control chamber 207 and a membrane chamber 209 including a medium in which the volume expands as the temperature changes.

Bonding between substrates such as bonding of the first substrate and the second substrate may be performed by hot pressure bonding, adhesive bonding or ultrasonic bonding.

A membrane 201 is formed in at least a portion of the membrane chamber 209 to divide the flow control chamber 202 and the pressure control chamber 207 and to elastically deform when the pressure in the pressure control chamber 207 increases. The fluid flow of the channels 210 is controlled by occupying the flow control chamber 202.

In the temperature control substrate 208, a heater 205, a temperature sensor 206, and an electrode 213 are formed to control the temperature of the medium of the pressure control chamber 207.

Of the channels 210 on the first substrate 203, the flow control chamber 202, the inlet 211 and the outlet 212, the membrane chamber 209 on the second substrate 204, the pressure control chamber 207 Machining includes NC (Numerical Control) Machining, Laser Ablation, Electric Discharge, Casting, Stereolithography, Rapid Prototyping, Photolithography, Hot Embossing ) And conventional polymer processing methods such as injection molding. In particular, hot embossing or injection molding is suitable for low cost, multiple production.

The heating of the closed pressure control chamber 207 consists of power transfer to the heater 205 through the electrode 213 formed on the temperature control substrate 208, the temperature control of the pressure control chamber 207 is a heater Temperature measurement via a temperature sensor 206 adjacent to 205 is achieved by controlling power transfer to the heater 205. The above-mentioned hermetically sealed pressure control chamber 207 is preferably made of a material having a low heat transfer rate such as plastic, so that heat of the heater 205 is mainly used to warm air, thereby minimizing heat loss.

3A and 3B are cross-sectional views illustrating a valve operation according to the shape change of the membrane shown in FIG. 1.

3A and 3B, the pressure control chamber 307 is sealed by air by the membrane 301, the second substrate 304, and the temperature control substrate 308. Heating the air in the pressure control chamber 307 by the heater 305 formed in the temperature control substrate 308 increases the volume due to thermal expansion of the air, thereby increasing the pressure of the sealed air. The increased pressure deforms the thin membrane 301, which is elastically deformable, to block the flow control chamber 302. That is, when the pressure of the pressure control chamber 307 becomes greater than the pressure of the liquid flowing through the channels and the flow control chamber 302, the flow control chamber 302 is reduced or blocked by the membrane 301. Conversely, when the heating of the temperature control substrate 308 through the heater 305 is stopped, the heat in the pressure control chamber 307 causes the flow control chamber 302, the membrane 301, the second substrate 304 and the temperature control substrate to stop. It is delivered to 308 and the temperature of the air in the pressure control chamber 307 is lowered and the air is contracted and the pressure in the pressure control chamber 307 is lowered so that the membrane 301 is elastically restored and returned to its original state. The thermopneumatic microvalve is in an open state at room temperature without heating (see FIG. 3A), and becomes clogged by heating (see FIG. 3B).

4A and 4B are cross-sectional views and diagrams for describing flow rate control according to the shape change of the membrane shown in FIG. 1.

4A and 4B show the relationship between the gap δ between the membrane 401 and the top surface of the flow control chamber 402 and the temperature of the pressure control chamber 407 associated therewith. The gap δ is the height H of the flow control chamber 402 in the unheated initial state, and when the temperature of the pressure control chamber 407 increases to reach the membrane expansion start temperature T1, deformation of the membrane starts and the temperature increases. As the pressure in the pressure control chamber 407 increases, the gap δ gradually decreases, and the flow control chamber 402 is completely blocked when the blocking temperature T2 of the flow control chamber is reached. Thereafter, there is no further deformation of the membrane 401 with the additional temperature increase of the pressure control chamber 407. Here, the expansion start temperature T1 at which deformation of the membrane 401 begins is the temperature at which the pressure in the pressure control chamber 407 starts to be greater than the sum of the liquid pressure in the flow control chamber 402 and the membrane deformation start stress. The change in the gap δ between the membrane expansion start temperature T1 and the blockage temperature T2 of the flow control chamber may vary nonlinearly depending on the material and shape of the membrane 401. When adjusted, the thermopneumatic microvalve presented in the present invention can be used as a flow regulating valve.

5A-5D are some cross-sectional views illustrating various shapes of the flow control chamber.

5A to 5D, the flow control chamber 502 may have a structure in which the membrane 501 is deformed to push out the liquid in the flow control chamber and easily adhere to the upper surface of the flow control chamber 502. For example, it may be formed into a rectangle (see FIG. 5A), an ellipse (see FIG. 5B), a triangle (see FIG. 5C) or a rhombus (see FIG. 5D).

6 is a conceptual diagram illustrating the membrane fixing by bonding applied to an embodiment of the present invention.

Referring to FIG. 6, the membrane 601 is fixed through the combination of the first substrate 603 and the second substrate 604, wherein the combination of the first substrate 603 and the second substrate 604 is Hot pressure bonding, pressure-sensitive adhesive bonding, ultrasonic bonding, and the like can be used.

On the other hand, the thickness t of the membrane 601 is smaller than the height h of the membrane chamber 609 so that the membrane 601 partially contacts the first substrate 603 and the second substrate 604. It is preferable to be compressed and fixed by In addition, in consideration of expansion deformation of the membrane 601 in the horizontal direction by compression at the time of bonding, the membrane chamber 609 is preferably formed to be larger than the membrane 601 by an appropriate size d.

7 is a partial plan view illustrating various types of combinations of flow control chamber and membrane chamber.

Referring to FIG. 7, the flow control chamber 702 is located in the center of the membrane chamber 709 and larger than the width of the channels 710 and smaller than the membrane chamber 709. The shapes of the flow control chamber 702 and the membrane chamber 709 may be modified in size and shape according to changes in driving pressure, driving temperature, and the shape of the channels 710. For example, the shapes of the flow control chamber 702 and the membrane chamber 709 may be circular (see FIG. 7A), horizontal oval (see FIG. 7B), rhombus (see FIG. 7C), rectangular (see FIG. 7D) or vertical ellipsoid ( 7E).

On the other hand, the thermopneumatic microvalve according to the present invention can be applied to pump the liquid in the flow control chamber in a constant direction through the continuous heating and cooling of the pressure control chamber, in which case the use of a thermopneumatic micropump It is possible.

As described above, optimal embodiments have been disclosed in the drawings and the specification. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not intended to limit the scope of the present invention as defined in the claims or the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the thermopneumatic microvalve of the present invention can control the flow of the fluid and its flow rate by a simple driving method, and the manufacturing cost is low. In addition, it is easy to be applied to various biochips, lab-on-a-chips, biosensors and chemical sensors that require a variety of fluid control because it can be formed locally in the polymer fluid element with a simple manufacturing process, a simple control method and a wide driving range. . The thermopneumatic microvalve of the present invention can not only turn the flow of the fluid on and off but also control the flow rate by adjusting the strain of the membrane and can be applied to pump the liquid in the flow control chamber in a constant direction through continuous heating and cooling. Can be.

Claims (16)

Channels for flowing a fluid; A flow control chamber connecting the channels; A pressure control chamber comprising a medium in which the volume expands with temperature change; A temperature controller for controlling the temperature of the medium of the pressure control chamber; And And a membrane that divides the flow control chamber and the pressure control chamber and elastically deforms to occupy the flow control chamber when the pressure in the pressure control chamber increases, thereby controlling fluid flow in the channels. The method of claim 1, The thermopneumatic microvalve further comprises an inlet and an outlet of the fluid connected to the channels. The method of claim 1, And the side wall of the pressure control chamber is formed of a material having a low heat transfer coefficient. The method of claim 1, The pressure control chamber is a thermopneumatic microvalve characterized in that it has a truncated cone or pyramid shape. The method of claim 1, And the medium is air. The method of claim 1, The medium comprises a gas comprising nitrogen, oxygen, carbon dioxide and helium; Liquids including water, alcohols, acetone and mercury; And at least one selected from the group consisting of a paraffin, a gel, a polymer, and a solid material including a porous material. The method of claim 1, The side wall forming the flow control chamber and the pressure control chamber is a thermopneumatic microvalve, characterized in that formed of plastic without elastic deformation. The method of claim 1, And the cross section of the flow control chamber and the cross section of the pressure control chamber in contact with the membrane have the same shape. The method of claim 1, The temperature control unit is a thermopneumatic microvalve comprising a heater and a temperature sensor. The method of claim 1, The membrane is a thermopneumatic microvalve characterized in that the elastic deformation and recovery without permeation of gas and liquid. The method of claim 1, The membrane is a thermopneumatic microvalve, characterized in that formed of a material selected from the group consisting of silicone rubber, latex film and PDMS film. A first substrate having channels for flowing fluid and a flow control chamber connecting the channels; A second substrate having a sidewall and a membrane chamber of a pressure control chamber including a medium in which volume expands with a temperature change and bonded to the first substrate; A membrane formed in at least a portion of the membrane chamber to divide the flow control chamber and the pressure control chamber and to elastically deform to occupy the flow control chamber when the pressure in the pressure control chamber increases to control the fluid flow of the channels; And And a temperature control substrate including a heater and a temperature sensor to control the temperature of the medium of the pressure control chamber and forming one surface of the pressure control chamber. The method of claim 12, The first substrate and the second substrate is a thermopneumatic microvalve, characterized in that formed of plastic without elastic deformation. The method of claim 12, Bonding of the first substrate and the second substrate is a thermopneumatic microvalve, characterized in that performed by hot pressure bonding, adhesive bonding or ultrasonic bonding. The method of claim 12, And the thickness of the membrane is greater than the depth of the membrane chamber and the membrane is partially compressed and fixed upon bonding of the first substrate and the second substrate. The method of claim 12, And a cross section abutting the membrane of the pressure control chamber coinciding with a cross section of the flow control chamber and having a conical or pyramidal shape corresponding to the area of the heater.

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