JP6920250B2 - Micropump and fluid transfer device - Google Patents

Description

The present disclosure relates to micropumps and fluid transfer devices.

Conventionally, various micropumps for transferring a very small amount of fluid have been studied. Micropumps are used in analyzers and medical-related (medication, clinical trials, etc.) for the application of minute amounts of gas and liquid, and for the heat dissipation and cooling of electronic devices.

For example, in Patent Document 1, a diaphragm in which a piezoelectric material is bonded to a metal diaphragm, a pump chamber, and a fluid pump having a suction portion and a discharge portion having a check valve at a position facing the diaphragm of the pump chamber are used. It is disclosed.

Japanese Unexamined Patent Publication No. 2005-248713

The micro pump of the present disclosure is a micro pump having a diaphragm, a driving element, and a flow path member, and the flow path member is connected to a pump chamber facing the diaphragm and the pump chamber. A second valve, which is arranged between the first flow path and the pump chamber and the first flow path and allows fluid to flow from the first flow path to the pump chamber, and a second valve connected to the pump chamber. A depth of the pump chamber, which is arranged between the flow path and the pump chamber and the second flow path, includes a second valve for flowing fluid from the pump chamber to the second flow path. The pump becomes shallower from the portion where the first opening connected to the first flow path is arranged toward the portion where the second opening connected to the second flow path is arranged.

The fluid transfer device of the present disclosure includes the above-mentioned micropump and a drive circuit for driving the drive element.

The micropump is schematically shown, (a) is a perspective view, (b) is a cross-sectional view taken along the line AA of (a), and (c) is a cross-sectional view taken along the line BB of (a). It is a cross-sectional view of. It is a top view which shows typically the micropump. It is a top view of a valve member. It is sectional drawing which shows typically the piezoelectric element.

<Micro pump>
1 (a) is a perspective view of the micropump 1, FIG. 1 (b) is a cross-sectional view showing a part of the cross section taken along line AA of FIG. 1 (a), and FIG. 1 (c) is a view. It is sectional drawing which shows a part of the BB line cross section of 1 (a). The micropump 1 includes a diaphragm 2, a driving element 3, and a flow path member 6. The flow path member 6 includes a pump chamber 4, a first flow path 5a, and a second flow path 5b.

Channel member 6 includes a first member 6a including pump chamber 4, a first flow path 5a, and the second member 6c and a second flow path 5b, the first member 6a and the second member 6 c It includes a valve member 6b arranged between them. The valve member 6b will be described later.

The drive element 3 is arranged on one surface of the diaphragm 2, and the flow path member 6 is arranged on the other surface. The pump chamber 4 includes a first wall portion 4a which is the other surface of the diaphragm 2, a second wall portion 4b of the flow path member 6 facing the first wall portion 4a, and a first wall portion 4a and a second wall. It is composed of a third wall portion 4c connecting the portions 4b. In the present embodiment, there is a portion where the first wall portion 4a and the second wall portion 4b are connected without the third wall portion 4c, but such a portion may or may not be present. May be good.

The first flow path 5a is provided in the second member 6c arranged on the second wall portion 4b side of the pump chamber 4, and is connected to the first opening 7a provided in the second wall portion 4b of the pump chamber 4. ing. A first valve 8a is provided between the first flow path 5a and the pump chamber 4. The first valve 8a allows the fluid to flow from the first flow path 5a to the pump chamber 4 and stops the fluid from flowing from the pump chamber 4 to the first flow path 5a. However, the flow of the fluid in the opposite direction may not be completely stopped, but the flow of the fluid in one direction may be more difficult to flow than the flow of the fluid in the opposite direction.

The valve of the first valve 8 a is composed of a part of the valve member 8c, and the circular-shaped valve plate 6ba, is composed of a joint 6bb supporting the valve plate 6ba. In the state of the valve member 8c alone, the valve plate 6ba can be displaced upward and downward with respect to the valve member 8c by deforming the joint 6bb.

The pump chamber 4 side of the valve plate 6ba, opening is provided, the opening is made much larger than the valve plate 6ba. As a result, the valve plate 6ba can be displaced toward the pump chamber 4. An opening is provided on the first flow path 5a side of the valve plate 6ba, and the opening is smaller than that of the valve plate 6ba. As a result, the valve plate 6ba is prevented from being displaced toward the first flow path 5a. When there is a fluid flow from the pump chamber 4 to the first flow path 5a, the valve plate 6ba closes the opening on the first flow path 5a side, so that the fluid flows from the pump chamber 4 to the first flow path 5a. It doesn't flow much. When there is no fluid flow or there is no displacement of the valve plate 6ba, the valve plate 6ba may or may not block the opening on the first flow path 5a side, but the first If the opening on the flow path 5a side is closed, the passage of fluid until the flow of the fluid is generated and the opening is closed can be reduced.

The second flow path 5b is provided in the second member 6c arranged on the second wall portion 4b side of the pump chamber 4, and is connected to the second opening 7b provided in the second wall portion 4b of the pump chamber 4. ing. A second valve 8b is provided between the second flow path 5b and the pump chamber 4. The second valve 8b allows the fluid to flow from the pump chamber 4 to the second flow path 5b, and stops the fluid from flowing from the second flow path 5b to the pump chamber 4. The second valve 8b is the same as the first valve 8a except that the relationship between the sizes of the front and rear openings is reversed and the direction in which the fluid flows is reversed, and thus the description thereof will be omitted.

When the diaphragm 2 is deformed by the driving element 3 and the volume of the pump chamber 4 becomes large, the fluid is introduced into the pump chamber 4 through the first flow path 5a. On the other hand, since there is a second valve 8b from the second flow path 5b side, almost no fluid is introduced. When the diaphragm 2 is deformed by the driving element 3 and the volume of the pump chamber 4 becomes smaller, a part of the fluid in the pump chamber 4 is discharged through the second flow path 5b. On the other hand, since the first valve 8a is located on the first flow path 5a side, the liquid is hardly discharged.

The depth of the pump chamber 4, the arrangement has been that portion of the second opening 7b to the arrangement has been that portion of the first opening 7a which is connected to the first flow path 5a are connected to the second passage 5b It is getting shallower toward you. As a result, when the mixed fluid enters the pump chamber 4 in addition to the transferred fluid, the mixed fluid can be quickly discharged and the transferred fluid can be efficiently transferred. Specifically, the first surface 4a of the pump chamber 4 is a diaphragm 2 to be displaced, the distance from the diaphragm 2 to the first opening 7a is closer, both fluid and entrained liquid to transfer is discharged It will be easier.

The fluid to be transferred is, for example, water, an organic solvent, or a solution or dispersion of something in them. The mixed fluid is, for example, air, so it is a gas. That, or coming air bubbles from the outside of the liquid during transport, when the bubbles from the more liquid to a temperature change occurs, it can be rapidly discharged bubbles. If the amount of bubbles is small, the bubbles will be spherical. If the diameter in depth and comparable pump chamber 4 of a sphere, or we discharge issued easy first opening 7a. That is, if the depth of the pump chamber 4 of the first opening 7a is shallow, even if the bubbles are small, they are easily discharged. If the diaphragm 2 is used with the diaphragm 2 facing up, it becomes difficult for air bubbles to be discharged. Even in such a state, if the depth of the pump chamber 4 of the first opening 7a is shallow, the bubbles are discharged. easy. In general, even when a fluid having a lower density than the transferred fluid is mixed, it is easily discharged. Further, when the operation is performed from a state in which a gas such as air is first contained, the gas can be discharged and the state can be quickly shifted to a steady state in which only the liquid is transferred.

The depth of the pump chamber 4 is from the first wall portion 4a facing the second wall portion 4b where the first opening 7a and the second opening 7b are arranged to the second wall portion 4b. It is a distance, which is a distance measured so as to be orthogonal to the first wall portion 4a. Since the center of the first opening 7a and the second opening 7b is an opening, the depth is measured by the second wall 4b around the opening. When different depths depending on the location may be, for example, the average depth of the second wall portion 4b of the four directions as viewed opening area centroid or al. Further, if the second wall portion 4b is a flat surface, the flat surface may be extended to the area center of gravity of the opening, and the depth may be set to the intersection of the flat surface and the area center of gravity.

The point G shown in FIG. 2 is the center of gravity of the area when the pump chamber 4 is viewed in a plan view. When the second opening 7b is arranged on the opposite side of the first opening 7a with respect to the area center of gravity G of the pump chamber 4, the fluid moves from the first opening 7a to the second opening due to the displacement of the diaphragm 2. It becomes easy to flow to the portion 7b, and both the transferred fluid and the mixed fluid are easily discharged from the second opening 7b.

The depth of the pump chamber 4 of the second region 9b shown in FIG. 2, which is the region opposite to the first opening 7a with respect to the second opening 7b, is the depth of the pump chamber 4 of the second opening 7b . If it is too shallow, bubbles and low-density liquids approach the second wall portion 4b in the second region 9b, so that they are easily discharged from the second opening 7b.

The first opening 7a, a region opposite the second opening 7b, the pump chamber depth of 4 in the first region 9 a if Shimese in FIG. 2, the depth of the pump chamber 4 of the first opening 7a If it is deeper than that, a shallow portion can be provided in the pump chamber 4 and the volume of the pump chamber 4 can be increased. That is, the volume of the pump chamber 4 can be increased without increasing the depth of the pump chamber 4 of the second opening 7b or the second region 9b. By increasing the volume of the pump chamber 4 to some extent, the amount of fluid transferred can be increased.

In the cross section of the pump chamber 4 including at least the first opening 7a and the second opening 7b, the depth of the entire pump chamber 4 should be shallow in the direction from the first opening 7a to the second opening 7b. in the above effects more can and enhance Turkey.

When the planar shape of the pump chamber 4 is rectangular and the first opening 7a and the second opening 7b are arranged along one of the rectangular diagonal lines D, the first opening 7a to the second opening 7a to the second Since the width of the pump chamber 4 becomes narrower toward the opening 7b, air bubbles and a liquid having a low density are likely to be discharged from the second opening 7b.

The first flow path 5a extends from the first opening 7a in the direction in which the depth of the pump chamber 4 becomes shallower, so that the fluid easily flows toward the slanted first valve 8a, and the fluid flows. Will be easier to introduce. Further, since the first flow path 5a is arranged in a portion of the flow path member 6 in which the pump chamber 4 occupies a small proportion, the degree of freedom in designing the width and depth of the flow path is increased.

Since the second flow path 5b extends from the second opening 7b in the direction in which the depth of the pump chamber 4 becomes shallower, the fluid can easily flow from the slanted second valve 8b, and the fluid is discharged. It becomes easier to do. Further, since the second flow path 5b is arranged in a portion of the flow path member 6 in which the pump chamber 4 occupies a small proportion, the degree of freedom in designing the width and depth of the flow path is increased.

Further, the flow path member 6 has a columnar shape whose upper surface is a portion where the diaphragm 2 is arranged, and the upper surface thereof and the lower surface of the first member 6a including the pump chamber 4 and the lower surface of the first member 6a. The second member 6c, which is arranged on the side and includes the first flow path 5a and the second flow path 5b, is arranged between the first member and the second member 6c, and a part of the first member is first. a valve member 6b which constitutes the movable portion of the valve 8a and the second valve 8b, includes a, the lower surface of the first member 6a is inclined with respect to the upper surface, the depth of the above-described When the pump chamber 4 in the state is provided, the space efficiency is improved, and the micropump 1 can be made smaller.

The first member 6a and the second member 6c are injection-molded from ABS (acrylonitrile butadiene styrene), PC (polypropylene), PP (polypropylene), POM (polyacetal), PA (polyamide) , TPE (elastomer) and the like. Can be made with.

As the diaphragm 2, a metal plate, a glass epoxy plate, a resin sheet, a rubber sheet, or the like is used. The diaphragm 2 may be formed by laminating, for example, a metal plate and an insulating film. If the metal plate is on the pump chamber 4 side and the insulating film is arranged on the drive element 3 side, sufficient insulation between the metal plate and the electrodes of the drive element 3 can be sufficiently secured, and the vibration caused by the drive element 3 is suppressed by the diaphragm 2. It is possible to efficiently transmit to and realize excellent fluid transfer efficiency. The metal plate and the insulating film may be adhered to each other with, for example, an adhesive. As the adhesive, Epoxy resins based, silicone chromatography emission resin system, can be used known ones such as polyester Le resins systems, but is not limited thereto. Further, as a curing method of the resin used for the adhesive, any method such as thermosetting, photocuring or anaerobic curing may be used.

As the material of the metal plate, for example, stainless steel, aluminum, titanium or the like may be used. In particular, stainless steel is preferable as a metal plate from the viewpoint of corrosion resistance, heat resistance, and oxidation resistance against fluid.

As the insulating film, such as polyethylene (PE), polyimide (PI), polypropylene (PP), may be used a resin film such as polyethylene Chile terephthalate (PET). As the insulating film, it is preferable to use a film having a coefficient of thermal expansion larger than that of the metal plate. By using a insulating film having a coefficient of thermal expansion larger than that of the metal plate, it is possible to obtain a diaphragm 2 having no slack in the insulating film when the insulating film and the metal plate are thermocompression bonded, and the driving element. The vibration caused by 3 can be efficiently transmitted to the diaphragm 2.

Further, the insulating resin layer may be arranged on the drive element 3. The insulating resin layer protects the driving element 3 and absorbs and reduces driving noise and miscellaneous vibration caused by vibration of the driving element 3 (and diaphragm 2). The miscellaneous vibration refers to unnecessary vibration that does not contribute to the driving of the pump.

As the driving element 3, for example, a unimorph type piezoelectric element 3 as shown in FIG. 4 is used. The piezoelectric element 3 is a laminate in which a piezoelectric layer 3a and an internal electrode layer 3b are alternately laminated, and the internal electrode layer 3b is connected layer by layer by external electrodes 3c formed on both end faces of the laminate. Is . The connection of the internal electrode layer 3b is not limited to the external electrode 3c, and a through conductor may be arranged in the via hole provided in the piezoelectric layer 3a. The piezoelectric layer 3a is polarized in the thickness direction and is displaced by an electric field applied between the internal electrode layers 3b via the external electrode 3c. The piezoelectric layer 3a is displaced and the piezoelectric element 3 expands and contracts in the plane direction, so that the diaphragm 2 is bent and displaced and vibrated in the thickness direction. The piezoelectric element 3 may have a surface electrode 3d on the surface in the thickness direction. By having the surface electrode 3d, the outermost piezoelectric layer 3a can be displaced and used as an active layer.

The insulating resin layer may be provided so as to cover the driving element 3 and the diaphragm 2 around the driving element 3. By covering the drive element 3 and the diaphragm 2 around it with an insulating resin layer, the adhesion between the drive element 3 and the diaphragm 2 can be improved, and the displacement of the drive element 3 is efficiently transmitted to the diaphragm 2. be able to. As a material of the insulating resin layer, for example, epoxy resin, acrylic resin, or the like may be used silicone over emissions based resin or rubber, but is not limited thereto.

A frame may be arranged so as to surround the driving element 3 on the surface of the diaphragm 2 on which the driving element 3 is arranged. The height of the frame is larger than the thickness of the drive element 3. The insulating resin layer may be filled inside the frame. By arranging the frame and making the height larger than the thickness of the drive element 3, the range of motion of the drive element 3 and the diaphragm 2 can be secured. For example, even if the micropump 1 is mounted on a substrate or the like, they are adjacent to each other. The drive of the micropump 1 is less likely to be hindered by contact of parts or the like. As the frame, for example, a stainless metal plate or the like may be used.

<Fluid transfer device>
In the fluid transfer device including the above-mentioned micropump 1 and the drive circuit for driving the drive element 3, the drive element 3 is driven by the drive circuit to vibrate the diaphragm 2, and the fluid is introduced and discharged in the pump chamber 4. It can be carried out. If the micropump 1 further includes a detection circuit that detects the displacement of the drive element 3, the detection circuit detects the displacement of the drive element 3, and when an abnormality occurs in the displacement of the drive element 3, the pump is driven. It is possible to quickly take measures such as stopping.

When the drive element 3 is driven by the drive signal transmitted from the drive circuit, the diaphragm 2 to which the drive element 3 is adhered vibrates and a pressure wave is generated in the fluid (liquid) in the pump chamber 4. The generated pressure wave propagates to the second wall portion 4b and the third wall portion 4c of the pump chamber 4. Pressure wave propagating in the second wall portion 4b and the third wall portion 4c is reflected by the second wall portion 4b and the third wall portion 4c, reflected wave propagates to the diaphragm 2 to vibrate the drive element 3. The detection circuit detects the vibration of the drive element 3 due to the reflected wave.

The micropump and fluid transfer device of the present embodiment can be used for an electronic device that supplies a very small amount of gas or liquid, especially a liquid, such as an analyzer or a medical device (medication, clinical test, etc.), so that the micropump and the fluid transfer device can be used for compact flow control and flow control. It is possible to realize an electronic device having excellent reliability and reduced noise and vibration.

1: Micropump 2: Diaphragm 3: Drive element 3a: Piezoelectric layer 3b: Internal electrode layer 3c: External electrode 3d: Surface electrode 4: Pump chamber 4a: First wall part 4b: Second wall part 4c: Third wall Part 5a: 1st flow path 5b: 2nd flow path 6: Flow path member 6a: 1st member 6b: Valve member 6c: 2nd member 7a: 1st opening 7b: 2nd opening 8a: 1st valve 8b : 2nd valve 9a: 1st region 9b: 2nd region 11: Connection pipe

Claims (10)

Diaphragm and
With the drive element
Flow path member and
Is a micropump with
The flow path member
The pump chamber facing the diaphragm and
The first flow path connected to the pump chamber and
A first valve, which is arranged between the pump chamber and the first flow path and allows a fluid to flow from the first flow path to the pump chamber,
The second flow path connected to the pump chamber and
It is arranged between the pump chamber and the second flow path, and includes a second valve for flowing a fluid from the pump chamber to the second flow path.
The depth of the pump chamber is from the portion where the first opening connected to the first flow path is arranged to the portion where the second opening connected to the second flow path is arranged. A micro pump that is shallow. The micropump according to claim 1, wherein the second opening is arranged on the opposite side of the first opening with respect to the area center of gravity of the pump chamber when viewed in a plan view from the diaphragm side. The micro according to claim 1 or 2, wherein the depth of the pump chamber on the opposite side of the first opening is shallower than the depth of the pump chamber of the second opening with respect to the second opening. pump. According to any one of claims 1 to 3, the depth of the pump chamber on the opposite side of the second opening to the first opening is deeper than the depth of the pump chamber of the first opening. The described micropump. In the cross section of the pump chamber including at least the first opening and the second opening, the depth of the entire pump chamber is shallow in the direction from the first opening toward the second opening. , The micropump according to any one of claims 1 to 4. The invention according to any one of claims 1 to 5, wherein the plane shape of the pump chamber is rectangular, and the first opening and the second opening are arranged along one of the diagonal lines of the rectangle. Micropump. The micropump according to any one of claims 1 to 6, wherein the first flow path extends from the first opening in a direction in which the depth of the pump chamber becomes shallower. The micropump according to any one of claims 1 to 7, wherein the second flow path extends from the second opening in a direction in which the depth of the pump chamber becomes shallower. The flow path member has a columnar shape in which the portion where the diaphragm is arranged is the upper surface.
And the first member including the upper surface and the pump chamber,
Is disposed on the lower side of the first member, a second member comprising said first flow path and the second flow path,
It is arranged between the first member and the second member, and partially includes a valve member that constitutes the first valve and a movable portion of the second valve.
The micropump according to any one of claims 1 to 8, wherein the lower surface of the first member is inclined with respect to the upper surface. A fluid transfer device comprising the micropump according to any one of claims 1 to 9 and a drive circuit for driving the drive element.

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