JP2022118970A - Microvalve and micropump using the same - Google Patents

Abstract

A microvalve suitable for a micropump capable of accurately delivering liquids other than ECF and a micropump using the same are provided. A microvalve includes a main body having an inlet opening, an outlet opening, a valve chamber communicating with the inlet opening and the outlet opening, and a differential pressure chamber, and between the valve chamber and the differential pressure chamber. a valve drive passage having both ends communicating with the differential pressure chamber; a working fluid injected into the differential pressure chamber and the valve drive passage; and arranged in the valve drive passage. and a valve electrode unit comprising: two valve negative electrodes arranged along the valve drive path; and a valve positive electrode arranged between the valve negative electrodes. have [Selection drawing] Fig. 1

Description

There is an application for exception to loss of novelty

The present invention relates to a microvalve and a micropump using the same.

In recent years, research on micropumps using functional fluids has been progressing. A functional fluid is a general term for fluids that express specific functionality by an external stimulus. Functional fluids include magnetic fluids, magneto-rheological fluids, electro-rheological fluids, electric field conjugate fluids, etc. Actuators using these are already used in industrial products and the like.

An electro-conjugate fluid (hereinafter referred to as ECF), which is one of functional fluids, is a functional fluid that generates active flow upon application of a DC voltage. A pump using an ECF is expected to be a hydraulic source suitable for a small-sized fluid delivery system because it can generate a flow simply by applying a voltage to a minute electrode without requiring a mechanical configuration.

In particular, pumps using ECFs are suitable for micropumps with high output power densities because the smaller the size of the electrode pair, the higher the power density. Patent Literature 1 discloses a heat diffusion device equipped with a pump using an ECF in order to cool a CPU or the like of a personal computer.

JP 2016-119326 A

By the way, the pump using ECF of Patent Document 1 is suitable for flowing ECF, but has a problem that it cannot flow fluids other than ECF. Further, in the ECF pump of Patent Document 1, the triangular pole electrode and the slit electrode are paired, and the ECF flows only in one direction from the tip of the triangular pole to the slit. There is also the problem that they cannot be performed alternately.

On the other hand, by utilizing the property that the ECF and water do not mix in the microchannel and arranging the triangular prism electrodes facing each other with the slit electrode in between, the ECF is alternately flowed in both directions, thereby improving the syringe pump performance. Research is also being conducted to demonstrate its function. However, if the ECF is only sucked and discharged alternately, the function as a pump for delivering fluid cannot be exhibited, so a valve that opens and closes according to the operation of the syringe pump is required.

On the other hand, elastic pieces are attached to the inlet port and the outlet port of the syringe pump so that when the pressure inside the syringe drops due to suction, the elastic piece on the outlet port side closes and the elastic piece on the inlet port side opens. Another idea is to provide a passive valve that closes the elastic piece on the inlet port side and opens the elastic piece on the outlet port side when the pressure inside the syringe increases due to the pushing action. However, with such a passive valve, response delay of the elastic piece, fluid leakage, and the like are likely to occur, and a very small amount of fluid cannot be sent out with high accuracy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a microvalve suitable for a micropump capable of accurately delivering liquids other than ECF, and a micropump using the same.

The microvalve of the present invention is
a body having an inlet opening, an outlet opening, a valve chamber communicating with the inlet opening and the outlet opening, and a differential pressure chamber;
an elastic membrane disposed between the valve chamber and the differential pressure chamber;
a valve drive path having both ends communicating with the differential pressure chamber;
a working fluid injected into the differential pressure chamber and the valve drive path;
a valve electrode unit disposed in the valve drive path;
The valve electrode unit has two valve negative electrodes arranged along the valve drive path and a valve positive electrode arranged between the valve negative electrodes,
When a voltage is applied between one of the valve negative electrodes and the valve positive electrode, the working fluid flows from one end of the valve drive path into the differential pressure chamber, thereby the elastic membrane deformed by the increased pressure of the working fluid on the side closes the outlet opening;
When a voltage is applied between the other of the valve negative electrodes and the valve positive electrode, the working fluid flows into the differential pressure chamber from the other end of the valve drive path. The elastic membrane deformed by an increase in pressure of the working fluid on the other end closes the inlet opening.

ADVANTAGE OF THE INVENTION According to this invention, the microvalve suitable for the micropump which can send liquids other than ECF with high precision, and a micropump using the same can be provided.

FIG. 1 is a perspective view of a micropump with microvalves according to an embodiment of the present invention. FIG. 2 is a perspective view showing the micropump separated into upper and lower halves. FIG. 3 is a diagram schematically showing a pump electrode unit arranged within a plunger passage. FIG. 4 is a side view taken along line AA of FIG. 1. FIG. FIG. 5(a) is a diagram schematically showing a micropump, and FIG. 5(b) is a diagram showing FIG. 5(a) cut along line BB of FIG. 5(a). be. FIG. 6(a) is a diagram schematically showing the state of fluid suction in a micropump, and FIG. 6(b) is a diagram showing FIG. 6(a) at the position of line BB in FIG. It is a figure which cut|disconnects and shows. FIG. 7(a) is a diagram schematically showing the discharge state of the fluid in the micropump, and FIG. 7(b) is the position of FIG. 7(a) taken along line BB in FIG. It is a figure which cut|disconnects and shows. FIG. 8A is a graph showing the voltage applied between the electrodes of the valve electrode unit of the micropump on the horizontal axis and the average value of the hydraulic pressure in the second opening on the vertical axis. FIG. 8B is a graph showing the voltage applied between the electrodes of the valve electrode unit of the micropump on the horizontal axis and the average value of the hydraulic pressure in the first opening on the vertical axis. FIG. 9A is a graph showing the elapsed time from the start of suction of the micropump on the horizontal axis and the flow rate of the liquid passing through the opening on the vertical axis, and FIG. is a graph showing the elapsed time on the horizontal axis and the flow rate of the liquid passing through the opening on the vertical axis. FIG. 9(c) is a graph showing the voltage applied between the electrodes of the pump electrode unit of the micropump on the horizontal axis and the average flow rate of the liquid passing through the first opening during suction on the vertical axis. be. FIG. 9D is a graph showing the voltage applied between the electrodes of the pump electrode unit of the micropump on the horizontal axis and the average flow rate of the liquid passing through the second opening during ejection on the vertical axis. FIG. 10(a) is a time chart showing the voltage applied between the electrodes of the valve electrode unit and the pump electrode unit of the micropump, and FIG. 10(b) shows the amount of liquid sucked by the micropump. is a time chart showing FIG. 10(c) is a graph showing the elapsed time from the start of suction of the micropump on the horizontal axis and the amount of liquid stored in the micropump on the vertical axis.

Hereinafter, embodiments of the present invention will be specifically described.

(Structure of micropump)
FIG. 1 is a perspective view of a micropump 10 with a microvalve according to an embodiment of the invention. FIG. 2 is a perspective view showing the micropump 10 separated into an upper half 20 and a lower half 30. FIG. These perspective views show the internal structure in a see-through state.

The micropump 10 is in the shape of a thin rectangular plate as shown in the drawing, and is composed of an upper half portion 20 and a lower half portion 30 . If the micropump 10 is formed using a semiconductor manufacturing process, it can be mass-produced in spite of its fine structure, but the manufacturing method is not limited.

The upper half part 20 has a rectangular plate-shaped upper case 21 and a syringe path 22 formed in a zigzag shape in the upper case 21 . The lower half portion 30 includes a rectangular plate-shaped lower case 31 having the same outer shape as the upper case 21, a U-shaped plunger path 32 formed in the lower case 31, and a zigzag-shaped valve drive path 33. have The syringe path 22 and the plunger path 32 constitute a pump driving path, and the upper case 21 and the lower case 31 constitute a main body. Also, the syringe path 22, the plunger path 32, and the valve drive path 33 function as fluid paths.

One end of the syringe passageway 22 is connected to the valve chamber 23a (see FIG. 4) of the microvalve, and the other end of the syringe passageway 22 is connected to one end of the plunger passageway 32 at the boundary between the upper half portion 20 and the lower half portion 30. It is The other end of the plunger path 32 is connected to a plunger reservoir 37 (see FIG. 5). A plurality of pump electrode units 40 are arranged in series within the plunger passage 32 .

FIG. 3 is a diagram schematically showing the pump electrode unit 40 arranged in the plunger passage 32. As shown in FIG. The pump electrode unit 40 has a slit electrode (also called pump positive electrode) 41 and a pair of triangular pole electrodes (also called pump negative electrode) 42 and 43 arranged with the slit electrode 41 interposed therebetween. Other pump electrode units 40 have similar configurations. The inner walls of the plunger path 32, which are in contact with the slit electrode 41 and the triangular pole electrodes 42 and 43, are made of an insulator.

The slit electrodes 41 are arranged on both sides of the axis of the plunger path 32 with a gap therebetween. On the other hand, the triangular prism electrodes 42 and 43 are arranged on both sides of the slit electrode 41 along the plunger path 32 and have pointed ends directed toward the slit electrode 41 . Here, it is assumed that the triangular pole electrode 42 is arranged on the syringe path 22 side and the triangular pole electrode 43 is arranged on the reservoir 37 side.

A DC voltage, which is a high voltage of several tens of volts to several tens of kV, can be applied to the slit electrode 41 and the triangular pole electrodes 42 and 43 from a power source (not shown). The slit electrode 41 is connected to the positive electrode side, and the triangular prism electrodes 42 and 43 are connected to the negative electrode side. is closed to the negative electrode.

FIG. 4 is a side view cut along line AA in FIG. 1, and schematically shows the valve drive path 33. As shown in FIG. In FIG. 4, the upper case 21 of the upper half 20 is formed by stacking a first plate member 23, an elastic membrane 24 that can be elastically deformed, and a second plate member 25. As shown in FIG. Polydimethylsiloxane (PDMS), for example, is preferably used as the material of the elastic film 24 . Although not shown in FIG. 4, a zigzag groove corresponding to the syringe path 22 is formed in the first plate member 23, and the elastic membrane 24 and the lower half part 30 are adhered so as to cover the groove. , a syringe channel 22 (FIG. 2) is formed.

A first opening 25a and a second opening 25b are formed in the center side of the second plate member 25 to expose the lower surface of the elastic membrane 24. As shown in FIG. A valve chamber 23a is formed inside the first plate member 23 above the elastic membrane 24 including the first opening 25a and the second opening 25b. An inlet opening 23b communicating with the valve chamber 23a is formed above the first opening 25a, and an outlet opening 23c communicating with the valve chamber 23a is formed above the second opening 25b. Although not shown in FIG. 4, the valve chamber 23a also communicates with the syringe path 22. As shown in FIG. In this embodiment, the elastic membrane 24, the inlet opening 23b, and the outlet opening 23c constitute an active microvalve.

The lower case 31 of the lower half portion 30 is formed by stacking a third plate member 34 and a flat fourth plate member 35 . A differential pressure chamber 34a is formed in the third plate member 34 below the first opening 25a and the second opening 25b. The differential pressure chamber 34a is connected to one end of the valve drive path 33 schematically shown on the side of the first opening 25a, and is connected to the other end of the valve drive path 33 on the side of the second opening 25b. The differential pressure chamber 34a and the valve drive path 33 form a closed loop. The ECF injected into the valve drive path 33 and the ECF injected into the syringe path 22 and plunger path 32 may be the same or different. The first port 21a and the second port 21b are ports used when injecting the ECF into the differential pressure chamber 34a and the valve drive path 33. After injecting the ECF, they are closed using a clamp (not shown) or the like. be done.

Although the valve drive path 33 is shown separately from the lower half portion 30 in FIG. 4, it is actually formed inside the lower half portion 30 . Specifically, a zigzag groove corresponding to the valve drive path 33 is formed in the third plate member 34, and the valve drive path 33 ( 2) is formed.

A plurality of valve electrode units 50 (only one is shown in FIG. 4) are arranged in series in the valve drive path 33 . The valve electrode unit 50 has a slit electrode (also referred to as a valve positive electrode) 51 and a pair of triangular pole electrodes (also referred to as a valve negative electrode) 52 and 53 arranged with the slit electrode 51 interposed therebetween. Other valve electrode units have similar configurations. The inner wall of the valve drive path 33, which is in contact with the slit electrode 51 and the triangular prism electrodes 52 and 53, is made of an insulator. It is assumed that the triangular prism electrode 52 is arranged on the first opening 25a side, and the triangular prism electrode 53 is arranged on the second opening 25b side. The configuration of the valve electrode unit 50 is basically the same as that of the pump electrode unit 40 shown in FIG. 3, the slit electrode 41 in FIG. 52, 53. Duplicate descriptions are omitted below.

(Operation of micropump)
Next, operation of the micropump 10 will be described. FIGS. 5(a), 6(a), and 7(a) are diagrams schematically showing the micropump 10, and FIGS. 5(b), 6(b), and 7(b) are FIG. 5(a), FIG. 6(a), and FIG. 7(a) are cut along the line BB in FIG. 5(a). 5(b), 6(b), and 7(b), the valve electrode unit 50 is shown below the elastic membrane 24 for ease of understanding. placed in different locations.

5 to 7, the liquid to be delivered by the micropump 10 (here, water WT) is indicated by dots, and the ECF is indicated by hatching. The inlet opening 23b communicating with the valve chamber 23a is connected to the supply source of the water WT, and the outlet opening 23c communicating with the valve chamber 23a is connected to the supply destination of the water WT. Further, part of the syringe passage 22 communicating with the valve chamber 23a is also filled with water WT, and the rest of the syringe passage 22 and the plunger passage 32 are filled with ECF.

An ECF is also enclosed in the closed loop between the differential pressure chamber 34 a and the valve drive path 33 .

In this embodiment, the micropump 10 is caused to perform a syringe operation by utilizing the property that water WT and ECF, which is a kind of oil, do not mix with each other. Any liquid other than water can be pumped by the micropump 10 as long as it has a property of not being mixed with the ECF. In the syringe passage 22, the interface between the water WT and the ECF is defined as BD. As the ECF, for example, the fluid described in US Pat. No. 6,495,071 is used, but it is not limited to this.

Power supply to the pump electrode unit 40 and the valve electrode unit 50 is integrally controlled by a controller (not shown). When power is not supplied from the control device to the pump electrode unit 40 and the valve electrode unit 50, the stationary state shown in FIG. Although there is communication, no movement of water WT occurs because there is no pressure difference.

(inhalation motion)
At the start of operation of the micropump 10, when a DC voltage is applied to the slit electrode 51 of the valve electrode unit 50 and the triangular pole electrode 52 in response to a signal from the control device, an electrohydrodynamic phenomenon occurs in the valve drive path 33. , the ECF flows in the direction indicated by arrow C in FIG. 6(a).

Then, in the differential pressure chamber 34a, the pressure inside the second opening 25b increases more than inside the first opening 25a, and as a result, as shown in FIG. 6B, the elastic membrane 24 inside the second opening 25b is The elastic membrane 24 inside the first opening 25a is elastically deformed so as to protrude into the valve chamber 23a, and the elastic membrane 24 inside the first opening 25a is elastically deformed so as to protrude into the differential pressure chamber 34a.

With this operation, the elastic film 24 in the second opening 25b abuts against and closes the lower end of the outlet opening 23c in the valve chamber 23a, and the elastic film 24 in the first opening 25a moves the inlet opening 23b. Increase the distance from the bottom edge.

Next, a DC voltage is applied to the slit electrode 41 and the triangular prism electrode 42 of the pump electrode unit 40 by a signal from the control device. Due to the electrohydrodynamic phenomenon caused by this, the ECF flows within the syringe passage 22 in the direction indicated by the arrow D in FIG. Then, the interface BD between the water WT and the ECF moves away from the valve chamber 23a, and the hydraulic pressure in the valve chamber 23a decreases. At this time, since the outlet opening 23c is closed by the elastic film 24, the water WT can be sucked into the valve chamber 23a and the syringe path 22 through the inlet opening 23b. Further, since the gap between the inlet opening 23b and the elastic membrane 24 is widened, entry of the water WT is not hindered. The ECF overflowing from the syringe path 22 as the interface BD moves is stored in the reservoir 37 .

After the water WT is sucked up to a predetermined stroke, the control device stops power supply to the valve electrode unit 50 and the pump electrode unit 40 .

(Ejection operation)
After that, when a DC voltage is applied to the slit electrode 51 of the valve electrode unit 50 and the triangular pole electrode 53 by a signal from the control device, electrohydrodynamic phenomena occur in the valve drive path 33 as shown in FIG. ECF flows in the direction indicated by arrow E in .

Then, in the differential pressure chamber 34a, the pressure inside the first opening 25a increases more than that inside the second opening 25b, and as a result, as shown in FIG. 7B, the elastic membrane 24 inside the first opening 25a is The elastic membrane 24 inside the second opening 25b is elastically deformed so as to protrude into the valve chamber 23a, and the elastic membrane 24 inside the second opening 25b is elastically deformed so as to protrude into the differential pressure chamber 34a.

With this operation, the elastic film 24 in the first opening 25a abuts against the lower end of the inlet opening 23b in the valve chamber 23a to close it, and the elastic film 24 in the second opening 25b closes the outlet opening 23c. Increase the distance from the bottom edge.

Next, a DC voltage is applied to the slit electrode 41 and the triangular pole electrode 43 of the pump electrode unit 40 by a signal from the control device. Due to the resulting electrohydrodynamic phenomenon, the ECF flows in the syringe passage 22 in the direction indicated by the arrow F in FIG. 7(a). Then, the interface BD between the water WT and the ECF moves toward the valve chamber 23a, and the hydraulic pressure in the valve chamber 23a increases. At this time, since the inlet opening 23b is closed by the elastic film 24, the water WT in the valve chamber 23a can be discharged through the outlet opening 23c. Further, since the distance between the outlet opening 23c and the elastic film 24 is increased, the ejection of the water WT is not hindered. The ECF stored in the reservoir 37 is returned into the syringe path 22 according to the movement of the interface BD.

After the water WT is discharged up to a predetermined stroke, the control device stops power supply to the valve electrode unit 50 and the pump electrode unit 40 . Thus, the operation of the micropump 10 for one stroke is completed.

As an example of the control method of the micropump, a control mode of the micropump synchronized with the operation of the microvalve will be described below.
(1) When the inlet opening 23b is opened and the outlet opening 23c is closed by the operation of the microvalve, ECF is generated by applying a DC voltage between the triangular pole electrode 42 and the slit electrode 41 of the micropump 10. While moving from the syringe path 22 to the reservoir 37 side, the water WT is sucked into the valve chamber 23a from the inlet opening 23b.
(2) When the outlet opening 23c is opened and the inlet opening 23b is closed by the operation of the microvalve, ECR is activated by applying a DC voltage between the triangular pole electrode 43 and the slit electrode 41 of the micropump 10. While moving from the reservoir 37 side to the syringe path 22, the water WT is discharged from the valve chamber 23a through the outlet opening 23c.

If a sensor for detecting the position of the interface BD is arranged in the syringe path 22, the amount of movement of the interface BD can be known. The control device can accurately determine the timing of starting and stopping power supply to the electrode units 40 and 50 based on the signals from the sensors, thereby causing the micropump 10 to repeatedly perform one stroke of precise syringe operation. can be done.

Further, if the cross-sectional area of the syringe passage 22 is known, the amount of water WT to be discharged in one stroke can be obtained with high accuracy based on the signal from the sensor. At this time, in order to increase the resolution when detecting the interface BD, it is preferable to reduce the cross-sectional area of the syringe path 22 and ensure a long path length. Therefore, in the present embodiment, the syringe path 22 is formed in a zigzag shape to enable highly accurate measurement of the discharge amount without increasing the size of the micropump 10 . For this reason, the micropump 10 of the present embodiment can be suitably used for applications that dispense a very small amount of liquid such as chemicals with high precision.

It should be noted that the microvalve of this embodiment can also be applied to uses other than the micropump.

(Experimental result)
The results of experiments conducted by the inventors will be described below.
FIG. 8A is a graph showing the voltage applied between the electrodes of the valve electrode unit 50 of the micropump 10 on the horizontal axis and the average value of the hydraulic pressure in the second opening 25b on the vertical axis. FIG. 8B is a graph showing the voltage applied between the electrodes of the valve electrode unit 50 of the micropump 10 on the horizontal axis and the average value of the hydraulic pressure in the first opening 25a on the vertical axis. . In each graph, horizontal lines indicate the upper and lower limits of the standard error of the measured values.

According to the experimental results shown in FIG. 8, it can be seen that the hydraulic pressure inside the opening increases as the voltage applied between the electrodes of the valve electrode unit 50 increases. Therefore, by increasing the applied voltage, the elastic membrane 24 can be pressed toward the inlet opening 23b and the outlet opening 23c with a sufficient force, thereby reliably closing the inlet opening 23b and the outlet opening 23c. Fluid leakage can be suppressed.

9A is a graph showing the elapsed time from the start of suction of the micropump 10 on the horizontal axis and the flow rate of the liquid passing through the opening on the vertical axis, and FIG. 9B shows the discharge of the micropump 10. It is a graph showing the elapsed time from the start on the horizontal axis and the flow rate of the liquid passing through the opening on the vertical axis, where the voltage applied to the pump electrode unit was 0.4 kV. Graphs marked with ♦ indicate changes in the amount of liquid passing through the inlet opening 23b, and graphs marked with ◯ indicate changes in the amount of liquid passing through the outlet opening 23c. The amount of liquid drawn into the valve chamber 23a through the inlet opening 23b is represented by a negative value, and the amount of liquid discharged from the valve chamber 23a through the outlet opening 23c is represented by a positive value.

According to the experimental results shown in FIG. 9(a), during inhalation, the amount of liquid passing through the inlet opening 23b increases linearly with the elapsed time, but the amount of liquid passing through the outlet opening 23c is zero. It can be seen that the function of the microvalve to open the inlet opening 23b and close the outlet opening 23c is ensured.

According to the experimental results shown in FIG. 9B, the amount of liquid passing through the outlet opening 23c increases linearly with the elapsed time, but the amount of liquid passing through the inlet opening 23b is zero. It can be seen that the function of the microvalve to open the outlet opening 23c and close the inlet opening 23b is ensured.

FIG. 9C is a graph showing the voltage applied between the electrodes of the pump electrode unit 40 of the micropump 10 on the horizontal axis and the average flow rate of the liquid passing through the inlet opening 23b during inhalation on the vertical axis. be. In FIG. 9D, the horizontal axis represents the voltage applied between the electrodes of the pump electrode unit 40 of the micropump 10, and the vertical axis represents the average flow rate of the liquid passing through the outlet opening 23c during ejection. graph. In each graph, horizontal lines indicate the upper and lower limits of the standard error of the measured values.

According to the experimental results shown in FIGS. 9(c) and (d), as the voltage applied between the electrodes of the pump electrode unit 40 increases, the flow rate of the liquid passing through the opening also increases. Therefore, by increasing the applied voltage according to the application of the micropump 10, the liquid suction/discharge speed can be increased.

FIG. 10(a) is a time chart showing the voltage applied between the electrodes of the pump electrode unit 40 and the valve electrode unit 50 of the micropump 10, and FIG. 4 is a time chart showing the amount of liquid to be applied;

10(a) and 10(b), the outlet opening 23c is closed by applying a constant DC voltage to the slit electrode 51 and the triangular pole electrode 52 of the valve electrode unit 50 from time tv1. At this time, the inlet opening 23b is open. Next, when a constant DC voltage is applied to the slit electrode 41 and the triangular prism electrode 42 of the pump electrode unit 40 from time t1 to time t2, the amount of liquid sucked by the micropump 10 becomes linear from time t1 to time t2. increases to

Further, when the application of the DC voltage to the slit electrode 41 and the triangular prism electrode 42 is stopped at time t2, the micropump 10 stops sucking the liquid. Further, at time tv2, when the application of the DC voltage to the slit electrode 51 and the triangular prism electrode 52 of the valve electrode unit 50 is stopped, the inlet opening 23b and the outlet opening 23c are opened, but there is a difference between the two openings. Without pressure there would be no liquid flow. At this time, if no DC voltage is applied between the electrodes of the pump electrode unit 40 from time t2 to time t3, the amount of liquid stored in the micropump 10 will be constant. Although FIG. 10A shows that there is a time difference between time tv2 and time tv3 for easy understanding, tv2=tv3 actually.

From time tv3, the inlet opening 23b is closed by applying a constant DC voltage to the slit electrode 51 and the triangular pole electrode 53 of the valve electrode unit 50. FIG. At this time, the outlet opening 23c is open. Next, when the application of the DC voltage to the slit electrode 41 and triangular pole electrode 43 of the pump electrode unit 40 is started at time t3, the micropump 10 starts to discharge the liquid. Furthermore, by applying a constant DC voltage to the slit electrode 41 and the triangular prism electrode 43 from time t3 to time t4, the amount of liquid stored in the micropump 10 decreases linearly.

Further, when the application of the DC voltage to the slit electrode 41 and the triangular pole electrode 43 is stopped at time t4, the micropump 10 no longer discharges the liquid. After that, at time tv4, the application of the DC voltage to the slit electrode 51 and the triangular pole electrode 53 of the valve electrode unit 50 is stopped, so that the inlet opening 23b and the outlet opening 23c are opened. One stroke of the micropump 10 is performed from time tv1 to tv4.

FIG. 10C is a graph showing the elapsed time from the start of suction of the micropump 10 on the horizontal axis and the amount of liquid stored in the micropump 10 on the vertical axis. is changed to 0.3 kV (solid line), 0.4 kV (dotted line), and 0.5 kV (broken line).

According to the experimental results of FIG. 10(c), it can be seen that the higher the voltage applied between the electrodes of the pump electrode unit 40, the faster the suction can be performed (the slope of the graph becomes steeper).

10 micropump 20 upper half 24 elastic membrane 30 lower half 40 electrode unit for pump 50 electrode unit for valve

Claims (3)

a body having an inlet opening, an outlet opening, a valve chamber communicating with the inlet opening and the outlet opening, and a differential pressure chamber;
an elastic membrane disposed between the valve chamber and the differential pressure chamber;
a valve drive path having both ends communicating with the differential pressure chamber;
a working fluid injected into the differential pressure chamber and the valve drive path;
a valve electrode unit disposed in the valve drive path;
The valve electrode unit has two negative valve electrodes arranged along the valve drive path and a positive valve electrode arranged between the negative valve electrodes,
When a voltage is applied between one of the valve negative electrodes and the valve positive electrode, the working fluid flows from one end of the valve drive path into the differential pressure chamber, thereby the elastic membrane deformed by the increased pressure of the working fluid on the side closes the outlet opening;
When a voltage is applied between the other of the valve negative electrodes and the valve positive electrode, the working fluid flows into the differential pressure chamber from the other end of the valve drive path, thereby The elastic membrane deformed by an increase in the pressure of the working fluid on the other end closes the inlet opening.
A microvalve characterized by: When a voltage is applied between one of the valve negative electrodes and the valve positive electrode, the working fluid flows from one end of the valve drive path into the differential pressure chamber, thereby the elastic membrane deformed by a decrease in the pressure of the working fluid on the end side is separated from the inlet opening;
When a voltage is applied between the other of the valve negative electrodes and the valve positive electrode, the working fluid flows into the differential pressure chamber from the other end of the valve drive path, thereby The deformed elastic membrane moves away from the outlet opening due to the reduction in pressure of the working fluid at one end.
The microvalve according to claim 1, characterized in that: 3. The microvalve according to claim 2, wherein the inlet opening is connected to a liquid supply source and the outlet opening is connected to a liquid supply destination;
a pump drive path having one end connected to the valve chamber and the other end connected to a reservoir;
a pump electrode unit disposed within the pump drive path;
The pump electrode unit has two pump negative electrodes arranged along the pump drive path and a pump positive electrode arranged between the pump negative electrodes,
The liquid has a property of being immiscible with the working fluid, and is injected into the valve chamber and part of the pump drive path,
said working fluid is injected into the remainder of said pump drive path in contact with said liquid;
When the inlet opening is opened and the outlet opening is closed by operation of the microvalve, the working fluid is removed by applying a voltage between one of the pump negative electrodes and the pump positive electrode. moving from the pump drive path to the reservoir side and sucking the liquid from the inlet opening into the valve chamber;
When the outlet opening is opened and the inlet opening is closed by the operation of the microvalve, the working fluid is removed by applying a voltage between the other of the pump negative electrodes and the pump positive electrode. While moving from the reservoir side to the pump drive path, the liquid is discharged from the valve chamber through the outlet opening.
A micropump characterized by:

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