JP2009281362A - Micropump - Google Patents

Abstract

To obtain a micropump that can be easily molded and can be miniaturized.
SOLUTION: A chamber 3 formed on a base 2, a chamber nozzle 4 formed in the chamber 3, a chamber driving unit 5 for increasing or decreasing the volume of the chamber 3, and a central axis direction of the chamber nozzle 4 The formed outflow channel 7, the inflow channel 9 formed in a direction different from the outflow direction of the outflow channel 7, the outflow nozzle 6 of the outflow channel 7, the inflow nozzle 8 of the inflow channel 9, and the chamber nozzle 4 Each opening is disposed so as to face the same intersecting space portion 10, and a part of the fluid discharged from the chamber nozzle 4 is for avoiding collision with the fluid flowing in when passing through the inflow channel 9. The avoidance space portion 16 is provided in the inflow channel 9 and the flow path resistance of the inflow channel 9 is lower than that of the outflow channel 7. Micro-pump 1 which gave the difference.
[Selection] Figure 1

Description

  The present invention relates to a micropump based on a new operating principle without valves suitable for microfabrication.

Micropumps that are generally used for transporting fluids such as gas and liquid move fluid by changing the inflow and outflow portions of the fluid, the chamber for temporarily storing the fluid, and the volume of the chamber. It is comprised with the chamber drive part for making it do.
As a conventional example of the micro pump having such a configuration, there is a diffuser type pump 20 as shown in FIG. The diffuser type pump 20 has a chamber 22 formed in the center of a base 21, and one side of the chamber 22 is connected to the inflow part 23 and the other side is connected to the outflow part 24. The chamber 22 has a chamber driving unit 25 for changing the volume of the chamber 22, and the chamber driving unit 25 includes a diaphragm 26 and an actuator 27 that is fixedly attached to the diaphragm 26 and applies vibrations. The inflow port 23 has an inflow connection port 30 that opens to the outside through an inflow channel 29 that is reduced in diameter outwardly from an inflow port 28 that opens to the chamber 22. It is connected. Accordingly, the inflow channel 29 is formed in a conical cylinder shape whose diameter is reduced outward. Further, the outflow portion 24 has an outflow connection port 33 that opens to the outside through an outflow channel 32 that is expanded outward from an outflow port 31 that opens to the chamber 22, and a fluid feeding side that is not shown in the drawing. It is connected. Therefore, the outflow channel 32 is formed in a conical cylinder shape whose diameter increases toward the outside (for example, Patent Document 1).

According to the conventional diffuser type pump 20, when the volume of the chamber 22 is increased by the positive drive of the chamber driving unit 25, the fluid enters the chamber 22 through both the inflow channel 29 and the outflow channel 32. In addition, since the inflow port 28 of the inflow channel 29 is reduced in diameter toward the inflow connection port 30 and the outflow port 31 of the outflow channel 32 is expanded in diameter toward the outflow connection port 33, The amount of fluid flowing through port 28 is greater than the amount of fluid flowing from outlet channel 32 through outlet port 31. Conversely, when the volume of the chamber 22 is reduced by reverse driving of the chamber drive unit 25, the amount of fluid flowing out from the outflow channel 32 through the outflow port 31 is larger than the amount of fluid flowing out from the inflow channel 29 through the inflow port 28. . Such a phenomenon is due to the nature of the fluid such that the flow rate of the fluid flowing from the large opening to the small opening is smaller than the flow rate flowing from the small opening to the large opening. Due to the movement of the fluid in the chamber 22 by the chamber drive source 25 as described above, the amount of fluid entering through the inflow channel 29 is relatively larger than the amount of fluid entering through the outflow channel 32, and conversely, the fluid is discharged through the outflow channel 32. Since the amount of fluid to be discharged is larger than the amount of fluid discharged through the inflow channel 29, the fluid is transferred from the inflow portion 23 to the outflow portion 24 over time by continuing the forward / reverse driving of the chamber drive portion 25 alternately. In other words, the fluid flows from the fluid supply source to the feeding side.
JP 2005-299597 A

  According to the above-described prior art, since the check valve is unnecessary, the structure is simplified and the durability is expected to be improved. However, two inflow portions 23 and two outflow portions 24 are formed in the chamber 22 individually. Since it is necessary, two ports of the inflow port 28 and the outflow port 31 are necessary, which is problematic from the viewpoint of reducing the size of the chamber 22. In addition, when the inflow channel 29 and the outflow channel 32 are formed in a three-dimensional shape, it is necessary to incline the bottom surface, but in the case of microphone processing, the incline processing in the depth direction cannot be performed with high accuracy. is there.

  The present invention has been made in view of the above circumstances, and its means is that, in the micropump of the invention of claim 1, a chamber formed in the base and a chamber formed in the chamber A nozzle, a chamber driving unit for increasing or decreasing the volume of the chamber, an outflow channel formed in a central axis direction of the chamber nozzle, an inflow channel formed in a direction different from the outflow direction of the outflow channel, and the outflow When the outlet of the channel and the openings of the inlet nozzle and the chamber nozzle of the inlet channel face the same intersecting space, a part of the fluid discharged from the chamber nozzle passes through the inlet channel. An avoidance space for avoiding a collision with the fluid flowing into the inflow channel is provided in the inflow channel, Flow resistance of the inlet channel than is that which gave a difference in flow path resistance to be lower.

  In the micropump of the invention of claim 2, the flow path resistance is due to a difference in opening area between the outflow nozzle and the inflow nozzle.

  Further, in the micropump according to the invention of claim 3, the chamber driving unit is a diaphragm provided in the chamber and a piezoelectric actuator for driving the diaphragm.

  According to the above-mentioned means of the present invention, when the volume of the chamber is increased by the positive drive of the chamber driving unit, the fluid is drawn into the chamber through the chamber nozzle, and at this time, mainly through the inflow nozzle to the chamber 3 from the inflow channel. Be drawn. Although it is also drawn from the outflow channel through the outflow nozzle, since the flow resistance of the outflow channel is larger than that of the inflow channel, a large amount of fluid from the inflow channel is drawn into the chamber.

  Next, when the volume of the chamber is reduced by reverse driving of the chamber driving unit, fluid in the chamber is pushed out through the chamber nozzle. Most of the extruded fluid is pushed out at a speed in the direction of the central axis of the chamber nozzle, so that it enters the outflow nozzle provided close to the chamber nozzle in the direction of the central axis of the chamber nozzle and flows out. Flows through the channel.

  A part of the fluid pushed out from the chamber nozzle enters the inflow nozzle from the intersecting space and flows out to the inflow channel. Since the inflow channel is formed in the inflow channel, the fluid pushed out here and the next operation Large collisions with the incoming fluid are avoided and the amount of incoming fluid is avoided from being greatly reduced.

  As described above, the fluid from the inflow channel that is relatively connected to the fluid supply source is pushed out to the feed side through the outflow channel through this micropump by repeating forward and reverse driving of the chamber drive unit. Therefore, it will function as a micropump.

Accordingly, the micropump of the present invention can be reduced in size as a whole because only one chamber nozzle, which is a port opened in the chamber, is required as compared with the prior art.
In addition, each constituent element such as the chamber nozzle, the outflow nozzle, the outflow channel, the inflow nozzle, and the inflow channel may be a processing method that scrapes off from above at a right angle to the depth direction, and thus has an advantage that processing is easy.

  Further, when the difference in flow resistance between the outflow channel and the inflow channel is due to the difference in the opening area of the outflow nozzle and the inflow nozzle, there is an advantage that the processing is simple.

  Furthermore, when the chamber drive unit is a diaphragm and a piezoelectric actuator, it can be driven by switching the voltage alternately between forward and reverse, so that a micropump can be configured with a simple device.

  The best mode for carrying out the present invention will be described below with reference to FIGS. As shown well in FIGS. 1 and 2, the micropump 1 of the present invention includes a chamber 3 having a predetermined volume formed in a substantially central portion on one surface side of the base 2, and a part of the chamber 3. A chamber nozzle 4 serving as a fluid inlet / outlet of the chamber 3 formed by cutting out the chamber 3, a chamber driving unit 5 for increasing / decreasing the volume of the chamber 3, and an outflow nozzle 6 formed outside the chamber nozzle 4 in the central axis direction. And an inflow channel 9 having an inflow nozzle 8 formed in a direction different from the outflow direction of the outflow channel 7.

  The outflow nozzle 6, the inflow nozzle 8, and the chamber nozzle 4 are arranged in the vicinity of the chamber nozzle 4 so as to face in the same intersecting space portion 10. Further, one side of the base 2 that includes the constituent elements processed in the depth direction is covered and sealed with a lid member 11. The chamber driving unit 5 covers the opening of the chamber 3 on the opposite side of the lid member 11 so as to be sealed.

  The chamber driving unit 5 changes the volume of the chamber 3 to increase or decrease the internal fluid. The chamber driving unit 5 includes a diaphragm 12 that covers the chamber 3 and an actuator 13 that vibrates and drives the diaphragm 12. The actuator 13 is an electrostatic actuator, a piezoelectric actuator, a thermal actuator, an electromagnetic actuator, or the like, but when a piezoelectric actuator is used, it can be driven by switching the voltage alternately forward and reverse. A micropump can be configured with a simple device.

  In the outflow channel 7, the outflow nozzle 6 corresponding to the inlet of the outflow channel 7 faces the chamber nozzle 4 at a position slightly away from the chamber 3 in the central axis direction of the chamber nozzle 4. An outflow connection port 14 corresponding to the outlet of the outflow channel 7 is provided on one end side of the base 2, and is connected and connected from the outflow connection port 14 to a feeding side where fluid is required.

  The inflow channel 9 is formed between two directions from the outer periphery of the chamber 3 to the chamber nozzle 4, and is connected to an inflow connection port 15 formed on the other end side of the base 2. The inflow nozzle 8 serving as an outlet of the fluid supplied from a fluid supply source (not shown) is formed at a position facing each other across the opening in front of the chamber nozzle 4. In this embodiment, the flow direction of the outflow channel 7 is substantially perpendicular to the outflow direction, but the present invention is not limited to this, and any direction different from the outflow direction of the outflow channel 7 may be used.

  However, the angle formed by the central axis direction of the chamber nozzle 4 and the central axis direction of the inflow nozzle 8 of the inflow channel 9 is larger than the angle formed by the central axis direction of the chamber nozzle 4 and the central axis direction of the outflow nozzle 6 of the outflow channel 7. It is necessary to increase the flow rate of the fluid discharged from the chamber nozzle 4 to the outflow nozzle 6 so as to increase. Therefore, the size of the chamber nozzle 4, that is, the opening area is smaller than that of the outflow nozzle 6, and the outflow nozzle 9 is used in order to make the flow path resistance of the inflow channel 9 smaller than that of the outflow channel 7. 6 is preferably smaller than the opening area of the inflow nozzle 8. The outflow channel 7 in the vicinity of the outflow nozzle 6 and the inflow channel 9 in the vicinity of the inflow nozzle 8 are preferably formed in a straight line to reduce the flow resistance.

  Furthermore, the flow resistance of the inflow channel 9 is formed to be smaller than the flow resistance of the outflow channel 7. In this embodiment, there are two inflow channels 9, and the total cross-sectional area of each flow path and the total opening cross-sectional area of the inflow nozzle 8 are the cross-sectional area of the outflow channel 7 and the outflow nozzle 6. Each is formed so as to be larger than the opening cross-sectional area. As an aspect other than such an embodiment, the channels 7 and 9 are formed in different curvilinear shapes that form different irregularities on the inner wall surfaces of the inflow channel 9 and the outflow channel 7 to cause a difference in flow resistance. By means such as causing a difference in flow path resistance, giving different resistance to the fluid supply source connected to the outflow connection port 14 or the inflow connection port 15 or the one on the infeed side, or a combination thereof Also good.

  Furthermore, the number of inflow channels 9 is not limited to two, but may be one or three or more. In the case of a plurality, the total flow resistance of each inflow channel 9 is compared with the flow resistance of the outflow channel 7 for determination. Similarly, the number of outflow channels 7 may be two or more. In this case, the determination is made by comparing with the total flow resistance of each outflow channel 7.

  In this way, by making the flow resistance of the inflow channel 9 smaller than the flow resistance of the outflow channel 7, the pull-in amount from the inflow channel 9 is the pull-in amount of the outflow channel 7 when pulling in from the chamber nozzle 4. Try to be more.

  The inflow channel 9 has an inflow in order to mitigate and avoid a large collision between a fluid drawn from a fluid supply source (not shown) connected to the inflow connection port 15 and a part of the fluid discharged from the chamber nozzle 4. In the inflow channel 9 close to the nozzle 8, an avoidance space 16 having a larger cross-sectional area than other portions is formed. Although it is controlled by the chamber drive unit 5 so that the fluid passes through the inflow channel 9 alternately in the opposite direction, it takes time for the fluid to pass, so before the velocity of the fluid entering and exiting becomes zero Switching takes place. For this reason, since the fluid entering and exiting causes a collision in the inflow channel 9 and substantially increases the flow path resistance, the cross-sectional area of the inflow channel 9 may be in other locations. The avoidance space 16 larger than the cross-sectional area of the inflow channel 9 is formed, and the effect of weakening the flow path resistance due to these collisions is brought about.

  The chamber nozzle 4, the outflow nozzle 6, and the inflow nozzle 8 are arranged so as to open and face the same intersecting space portion 10, so that the fluid enters and exits from the chamber 3 through this one chamber nozzle 4. In addition, the check valve is not provided. In this embodiment, the chamber nozzle 4 and the outflow nozzle 6 are formed to face each other with a length in the width direction of the inflow nozzle 8. Each of the nozzles is formed in a groove shape by cutting the base 2 in the depth direction in a plane, but the distance in the depth direction does not have to be the same, for example, the opening area of the inflow nozzle 8 It is also possible to make a structure that is deeply cut to increase the size. In any case, each nozzle in the intersection space 10 is formed in a stepped shape that is easy to cut from above the base 2, and thus has a structure that can be easily processed. Further, since the chamber 3, the outflow channel 7 and the inflow channel 9 are also formed only by cutting in the depth direction from above, the micropump 1 as a whole can be easily processed.

  The operation of the micropump 1 of the present invention having the above configuration will be described with reference to FIGS. First, the primary inhalation shown in FIG. 5 will be described. When the actuator 13 of the chamber drive unit 5 is a piezoelectric actuator, when the diaphragm 12 is deformed in the direction of arrow A by applying a drive voltage and the volume of the chamber 3 is increased, a fluid supply source (not shown) The fluid is drawn into the chamber 3 from the connected inflow connection port 15 through the inflow channel 9, the inflow nozzle 8, the cross space 10, and the chamber nozzle 4. At this time, a part of the fluid is also drawn into the chamber 3 from the outflow channel 7 through the outflow nozzle 6, the intersecting space portion 10 and the chamber nozzle 4, but the flow path resistance of the inflow channel 9 is greater than the flow path resistance of the outflow channel 7. Therefore, more fluid from the inflow channel 9 is drawn into the chamber 3 than fluid from the outflow channel 7. In this primary suction, no reverse fluid flow occurs in the inflow channel 9 and the outflow channel 7.

  Next, the primary discharge shown in FIG. 6 will be described. When the diaphragm 12 is deformed in the direction of arrow B by applying a reverse drive voltage to the actuator 13 of the chamber drive unit 5 and the volume of the chamber 3 is reduced, the chamber nozzle 4, the outflow nozzle 6, the outflow channel 7 and the outflow connection Fluid is discharged through the mouth 14. At this time, fluid is also discharged from the inflow channel 9 through the chamber nozzle 4, the intersecting space portion 10, and the inflow nozzle 8, but since the opening of the outflow nozzle 6 is in the central axis direction of the chamber nozzle 4, the fluid is discharged from the chamber nozzle 4. The fluid to be discharged is discharged toward the central axis of the chamber nozzle 4 by the outflow speed. For this reason, a lot of fluid goes straight through the intersection space 10 and is discharged from the outflow nozzle 6 to the outflow channel 7. A part of the fluid is also discharged into the inflow channel 9 through the inflow nozzle 8 that opens at a position substantially orthogonal to the chamber nozzle 4 in the intersecting space portion 10. The inflow channel 9 has an avoidance space portion having a large cross-sectional area. 16 is formed, the speed of the fluid to be discharged is reduced here, and the collision with the fluid flowing in from the opposite direction is avoided due to the time difference, and the next process is integrated with the flowing fluid. Then it is drawn into the chamber 3.

As shown in FIG. 7, the second and subsequent suctions are performed in the same manner as the first, but at this time, since the flow of fluid in the reverse direction remains in the inflow channel 9, the inflow connection port 15 Although the speed of the fluid sucked from the crossing in the avoidance space 16 is partially reduced, a large amount of the sucked fluid passes from the chamber nozzle 4 into the chamber 3 through the inflow nozzle 8 and the cross space 10. Inhaled. A part of the fluid in the outflow channel 7 is also sucked into the chamber 3 from the chamber nozzle 4 through the outflow nozzle 6 and the intersecting space 10. However, since the fluid is discharged from the chamber nozzle 4 at a speed, the flow proceeds in the direction of the outflow connection port 14 while maintaining the speed in the outflow channel 7 to some extent. Even if an action occurs, it is difficult to change direction suddenly. In addition, since the flow resistance of the outflow channel 7 is larger than the flow resistance of the inflow channel 9, the amount of suction from the outflow channel 7 is small.
Similarly, secondary and subsequent discharges are also discharged from the outflow nozzle 6 via the outflow channel 7 as described above.

  By such an action of the chamber drive unit 5, the suction and discharge operations are repeatedly performed, and the fluid is continuously sent from the inflow connection port 15 to the outflow connection port 14. The fluid may be either gas or liquid.

  Since the micropump of the present invention can be effectively used for supplying gas and liquid in a micro device such as a micromachine, it is a useful invention with extremely high utility value for future micro application technology.

Overall perspective view of an embodiment of a micropump of the present invention XX sectional view of FIG. 1 is an enlarged view of the main part of FIG. Plan view of FIG. Perspective view and cross-sectional explanatory diagram of the main part of the primary inhalation Perspective view and cross-sectional explanatory view of the main part of the primary discharge Perspective view and cross-sectional explanatory diagram of the main part of the second and subsequent inhalations Perspective view and cross-sectional explanatory diagram of the main part of the second and subsequent discharges Cross-sectional illustration of a conventional micropump

Explanation of symbols

1 Micropump 2 Base 2
DESCRIPTION OF SYMBOLS 3 Chamber 4 Chamber nozzle 5 Chamber drive part 6 Outflow nozzle 7 Outflow channel 8 Inflow nozzle 9 Inflow channel 10 Crossing space part 11 Cover member 12 Diaphragm 13 Actuator 14 Outflow connection port 15 Inflow connection port 16 Avoidance space part

Claims (3)

  A chamber formed in the base, a chamber nozzle formed in the chamber, a chamber driving unit for increasing or decreasing the volume of the chamber, an outflow channel formed in the central axis direction of the chamber nozzle, and the outflow channel An inflow channel formed in a direction different from the outflow direction, and an outflow nozzle of the outflow channel, an inflow nozzle of the inflow channel, and an opening of the chamber nozzle are disposed so as to face the same intersecting space portion, and the chamber nozzle An avoidance space is provided in the inflow channel for avoiding a collision with a fluid flowing in when a part of the fluid discharged from the inflow channel passes through the inflow channel, and the flow resistance of the inflow channel is more than the outflow channel. A micropump characterized by having a difference in flow path resistance so as to reduce the flow rate.   The micropump according to claim 1, wherein the flow path resistance is based on a difference in opening area between the outflow nozzle and the inflow nozzle.   3. The micropump according to claim 1, wherein the chamber driving unit is a diaphragm provided in the chamber and a piezoelectric actuator for driving the diaphragm.

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