EP3841303B1 - Microblower - Google Patents

Description

Introduction

The invention relates to a miniaturized pump for compressible fluids. In particular, the invention relates to a microblower for gases or gas mixtures such as air in particular.

State of the art and disadvantages

Micropumps are well known in the art. According to one definition, they are used to pump fluids (liquids and gases) in small volumes. These are typically in the range of microliters to milliliters per minute.

In addition to the amount of fluid delivered per unit of time, the size of the pump, in particular its pump housing, can also be decisive in determining whether a micropump is present. In this respect, the term “micropump” also designates a particularly small housing, which has edge lengths in the range from a few millimeters to a few centimeters. Components such as power supply and control are often housed separately from said housing, which is why the term "micropump" in the narrower sense is limited to the components required for actual pumping (pump chamber, valves, housing). In particular, such a micropump is also the subject of the present invention.

Micropumps that are particularly suitable for pumping incompressible fluids (liquids) are based on the so-called peristaltic principle. Two or more piezoceramic discs vibrating alternately increase and decrease the volume of two adjacent pump chambers. The conveying direction is determined by the clever coupling of the chambers by means of movable check valves and a phase offset of the control. By varying the stroke or the frequency, the pump can pump a range of liquid volumes.

Micropumps constructed in this way are in principle suitable for pumping both liquids and gases; During operation of the micropump, the valves lead to a limitation of the pumping frequency due to their inertia. In addition, they are exposed to constant, mostly high-frequency stress, which places high demands on their mechanical properties. Another disadvantage is the noise emitted by the pump drive. At frequencies above approx. 300 Hz, these are clearly audible even with small dimensions, and at frequencies above approx. 1000 Hz the noise emission increases to a level that cannot be tolerated in many application scenarios. Operation above the hearing threshold of approx. 20 KHz is not possible due to the inertia of the valves. Accordingly, there is a practical limit to the flow rate.

Furthermore, micropumps are known which do without mechanical valves. Instead, they are operated in a narrow frequency range, preferably the resonance frequency of the 1st order or higher. They are designed in such a way that fluid dynamic effects come into play at the operating frequency, which lead to the formation of a preferred direction when pumping the fluid. So are from the pamphlet DE 11 2013 002 723 T5 , the pamphlet U.S. 2011/0076170 A1 as well as the publication U.S. 2016/0377072 A1 Known micropumps, which are operated at high frequencies, preferably lying in the inaudible range. The single actuator, in the form of a piezo disk, is attached to a membrane which provides passage openings for the fluid to be pumped. Fluid-filled chambers are present on both sides of the membrane. The flow conditions during operation of the pump lead to a vibration depending on the direction of the diaphragm different levels of fluid resistance in the corresponding chamber. In this way, the fluid is conveyed in the desired conveying direction.

A modification of the principle, in particular for conveying gases, is described in the publication EP 2 306 018 A1 disclosed. A piezo disc forms an oscillating plate together with a membrane to which it is attached. A hollow chamber is arranged on the side facing away from the piezo disc. This has a central opening. The oscillating unit, consisting of an oscillating plate and a hollow chamber, is mounted elastically in an outer housing that is open to the side of the piezo disc, so that the entire oscillating unit can oscillate in the direction of curvature of the piezo disc that drives it. The outer housing has an outlet opening, also in the center. There is an air gap between the swing assembly and the inside of the outer case. The part of the air gap that leads into the area that surrounds the side walls of the hollow chamber that run perpendicular to the surface of the piezo disk serves as the entry opening.

If the piezo disk, and with it the entire flywheel unit, is now made to oscillate, which preferably has the resonant frequency, then in an intake phase, gas is sucked in through the inlet opening and the adjoining area mentioned above. The negative pressure required for this develops in the gradually increasing area between the central opening of the hollow chamber and the outlet opening. In the subsequent application phase, this area is reduced again. By suitably designing the air gap and the size of the central opening in the hollow chamber and the outer housing, the above fluid dynamic effects are used and a preferred direction can be formed in which the gas is transported.

A disadvantage of the construction shown is the fact that the piezo disk is located in the area of the outer housing that is open to the outside, and that gas must also flow around it during operation. Mechanical damage or impairments due to environmental influences (humidity, aggressive gases, etc.) cannot be ruled out. In addition, the inlet and outlet openings are on opposite sides of the micropump. In certain cases, this can be disadvantageous, for example when the micropump is to be mounted on a "fluidic circuit board" in which fluid-carrying channels are present. The air gap between the swing unit and the inside of the outer housing also enlarges the outer housing and reduces the space available for the swing unit.

A further development of this micropump, which is provided in particular for gases, is known from the publication DE 10 2012 101 861 A1 known. Accordingly, in order to prevent impairment by dust or liquids sucked in during operation with the gas, the pump has a gas-permeable but liquid-impermeable fabric over the suction region, which fabric is preferably capable of vibrating. However, said protection also reduces the delivery capacity of the micropump, since part of the capacity is now required for transporting the gas through the tissue, which has a certain flow resistance.

Another solution, which is partly comparable to the micropump with a hollow chamber, is from the publication EP 2 090 781 B1 known. Here the piezo disc is also located on the outside of a hollow chamber with a central opening, which, however, cannot vibrate as a whole; only the wall designed as an oscillating membrane, to which the piezo disk is attached, can oscillate. Beyond the this Wall opposite, the central opening having wall is arranged at a distance another wall having the central outlet opening. The gap between the last-mentioned walls serves as the entrance opening. If the membrane is made to oscillate, the internal pressure in the hollow chamber changes, which propagates through the central opening into the aforementioned gap. There, negative pressure leads to gas being sucked into the gap, and subsequent excess pressure to blowing out the gas, preferably through the outlet opening.

US2016/010636 A1 shows another prior art micropump.

Object of the invention and solution

The invention is therefore based on the object of providing a device and a method which avoids the disadvantages of the prior art. Accordingly, a micropump according to the invention for compressible fluids should have improved insensitivity to mechanical and other external impairments. It should be suitable for mechanical connection to a surface and also allow improved utilization of the construction volume.

The object is achieved by a device according to claim 1 and a method according to independent claim 9. Advantageous embodiments can be found in the respective dependent subclaims, the following description and the figures.

Description

The micropump according to the invention and advantageous embodiments thereof are first described below. This is followed by a description of their use.

The micropump according to the invention serves to convey compressible fluids such as gases in particular.

The micropump comprises two main units, which, however, must not be considered independently of one another, but must be closely coordinated and thus form a common whole in order to ensure the desired fluid transport.

The first main unit is hereinafter referred to as the "swing unit" because (in the idealized case) it is the only one that moves during operation. The momentum unit comprises a disk-shaped, mostly round or rectangular piezo actuator, which typically has a diameter of a few (e.g. 1 - 5) millimeters up to a few (e.g. 1 - 4) centimeters and which, when activated, i.e. when a suitable voltage is applied, goes from a typically flat resting state to a typically curved deflection state. If necessary, a curvature in the opposite direction can be generated by applying an oppositely polarized voltage, which increases the usable stroke accordingly.

The piezo actuator is arranged on an inside and/or outside of an oscillating diaphragm. He is firmly connected to it, so that it carries out the curvature described above. It is also conceivable to design the piezo actuator and oscillating membrane in one piece, or even to see the latter as a sub-unit of the piezo actuator. The inside is the side that faces towards the blower chamber described below.

An oscillating plate is arranged opposite the inside of the oscillating membrane. Depending on the embodiment, this will preferably also move during operation. The vibrating plate has at least one centrally located blower opening. If this has several blower openings, they are preferably also located in the central area.

Between the oscillating diaphragm and the oscillating plate there is a peripheral wall connected to the two in a substantially gas-tight manner, so that inside the swing unit a Blower chamber is formed. The swing unit is therefore hollow on the inside, and the hollow space, ie the blower chamber, has (at least) one opening through which the fluid can flow in and out again.

The second main unit is hereinafter referred to as "housing". The swing unit can be completely accommodated in this, with a gap surrounding the swing unit being present. This is necessary because the flywheel unit is oscillatingly mounted in the housing in the direction of swing of the piezo actuator by means of at least one suspension, whereby it is clear that the gap must be dimensioned in such a way that no collision between the flywheel unit and the housing can occur during normal operation.

The suspension is intended to decouple the vibration unit from the housing surrounding it in terms of vibration. In this way, the efficiency of the micropump is increased, since no energy is lost through (undesirable) movement (i.e. resonating) of the housing.

The housing has at least one inlet or intake opening. Through this, fluid can flow into the interior of the housing.

The housing has (at least) one outlet opening, which is also arranged in the middle and is therefore opposite the blower opening. There is a gap between the two openings that is at least large enough to prevent a collision between the flywheel unit and the housing during normal operation.

According to the invention, the housing forms a closed space that also covers the piezoelectric actuator and thus protects it from environmental influences. In particular, the side of the oscillating diaphragm that points outwards, and with it the piezo actuator, are also covered by the housing.

According to the invention, the suction opening is also arranged radially (and thus perpendicularly to the vibration direction of the piezo actuator) or on an underside opposite the vibration unit. It has an intake channel that leads into a "pump chamber" located between the oscillating plate and the inside of the housing.

When the piezo actuator is operated in an oscillating manner, the oscillating unit can be made to oscillate relative to the housing, as a result of which the compressible fluid can be sucked in through the intake opening and discharged through the outlet opening.

The invention thus avoids the disadvantages known from the prior art. Since the piezo actuator is completely surrounded by the housing, this protects it from unwanted mechanical damage and environmental influences. However, protection is only possible due to the construction according to the invention, since the fluid does not flow through a suction opening which leads past the piezo actuator, as is sometimes practiced in the prior art. Since the intake opening is not opposite, but to the side of or on the same side as the outlet opening, the micropump according to the invention can also be mounted on a plate without closing one of the openings, or without one or even several corresponding holes for the openings in the plate being necessary. Finally, the micropump according to the invention makes optimum use of the installation space available to it, since the gap present at the side (in the area of the wall) only has to be large enough that the oscillating movement of the oscillating body is not impeded; Since the movement runs parallel to the (lateral) inner wall of the housing, a very small gap, for example 10 - 1000 µm, is sufficient. In contrast, the air gap according to the constructions known from the prior art must be large enough for the gas transport, which leads to a significantly larger distance and thus, with a comparable delivery rate, to a larger housing.

Various embodiments of the invention are described in more detail below.

According to one embodiment, the housing has a housing body and a housing cover. The housing body then has a pot-like shape with a bottom and surrounding walls.

According to a variant of this embodiment, the housing body is set up to accommodate all moving components, including the gap dimensions required for vibration. As a result, this allows the use of a very flat housing cover. In addition, all moving components can be inserted one after the other into the housing body during production and the housing can finally be closed with the housing cover. The lid can also be formed simply, i.e. without indentations.

According to another variant of this embodiment, at least parts of the movable components are arranged in an inside recess of the housing cover, or they move into and out of this at least in an oscillating manner during operation. This means that the body of the case can be flatter, since the lid also provides space for accommodating certain components. The production of housing parts of approximately the same thickness can be advantageous in particular for injection molded parts or for the simultaneous production of both parts by means of 3D printing.

According to one embodiment of the swing unit, the swing plate and wall are manufactured in an integrated manner. When assembled, the two components together thus have a pot-like shape, on which the oscillating membrane is placed as a kind of "cover" in order to provide the largely closed blower chamber.

It is even possible to integrate the oscillating membrane, for example by using 3D printing.

According to another embodiment of the swing unit, the swing plate and wall are manufactured as separate components. The oscillating plate can then be provided in particular as a flat, disc-shaped body on which a ring of a certain thickness is applied. The space which the ring encloses then defines the blower chamber. In this way, blower chambers of different heights can be easily produced, since only one ring of different thickness has to be used in each case; the oscillating plate can remain unchanged.

According to a further embodiment, the piezo actuator is arranged in a gas-tight manner with respect to the pump chamber. This means that the piezo actuator no longer comes into contact with the fluid to be pumped because the space in which it is located is sealed off. This can be achieved, for example, by designing the suspension to be continuous all the way round, or by providing an additional, thin protective membrane that does not impede the vibration. Thus, the gap between the wall of the swing unit and the inner wall of the housing is interrupted all around; only the partial volume of the interior of the housing in which the piezo actuator is not located (pump chamber) comes into contact with the fluid.

It should be noted that a design with non-separated partial volumes already leads to an improved separation of the piezo actuator and the fluid to be conveyed, since the latter is not constantly guided past the former, but at best penetrates the corresponding half-space in small quantities without being constantly exchanged.

The piezo actuator preferably has a diameter of 5 to 50 mm, and preferably 8 to 20 mm, and particularly preferably 10 to 15 mm.

The gap between the wall and the inside of the housing is preferably less than 0.01 to 1 mm, and more preferably less than 0.5 mm.

The micropump preferably has a total height of 3 to 10 mm, minus any sockets etc. that may be present; it is particularly preferably smaller than 8 mm.

According to a further embodiment, the diameter of the fan opening is between 3.0 and 0.1 mm, and preferably between 2.0 and 0.3 mm, and particularly preferably between 0.5 mm and 0.7 mm.

The diameter of the suction opening(s) is preferably between 0.1 and 10.0 mm, and preferably between 0.2 and 5.0 mm, and particularly preferably between 0.5 mm and 2.5 mm.

The diameter of the exit orifice(s) is preferably between 0.1 and 10.0 mm, and preferably between 0.25 and 5.0 mm, and most preferably between 0.7 and 0.9 mm.

Depending on the number of openings, this applies to each opening individually or to the sum of the cross sections of the respective openings.

The description of the use of the micropump according to the invention is now given below.

Accordingly, the method serves to convey a compressible fluid, such as in particular a gas, using a micropump as defined above; to avoid repetition, reference is made to the relevant passages above.

In an intake phase, the piezo actuator is controlled with a suitable voltage in such a way that it arches in the opposite direction to the blower opening. This creates a negative pressure in the blower chamber, which is caused by the above Fan opening also propagates into the pumping chamber, whereby fluid is drawn in through the suction port.

In a subsequent output phase, however, the piezo actuator is controlled in such a way that it now arches in the direction of the blower opening. Alternatively, there is no (active) control, so that the piezo actuator goes (back) into a typically level rest position. In each case, this leads to the negative pressure in the blower chamber regressing or even, measured against the ambient pressure, an overpressure being generated, which is also propagated through said blower opening into the pump chamber, whereby fluid is discharged through the outlet opening using the fluid-dynamic effects described above.

The rhythmic movement of the piezo actuator also causes the entire swing unit to vibrate.

The preferred direction, i.e. sucking in through the intake opening and dispensing through the outlet opening, is therefore achieved by the special design of the micropump, in particular by the presence of the blower chamber, the blower opening, the oscillating movement of the swing unit in relation to the housing surrounding it, and the arrangement of the intake and outlet openings.

The advantage of the method according to the invention lies in the fact that, when using the micropump according to the invention, it allows improved protection of the piezoactuator against undesired external influences, since the fluid is conveyed only outside the half-space containing the piezoactuator. The suspension divides the interior of the case into two half-spaces; one half-space contains the piezo actuator, the intake and outlet opening(s) open into the other half-space, and only this is actively flowed through by the pumped fluid.

According to a preferred embodiment, the oscillating plate also oscillates in the direction of movement of the piezo actuator, i.e. both plates move in approximately the same direction. In this way, improved generation of negative or positive pressure in the pump chamber can be achieved.

According to another preferred embodiment, the oscillating plate also oscillates, but in the opposite direction to the direction of movement of the piezo actuator, i.e. both plates move at the same frequency, but in precisely the opposite direction to one another. In this way, the oscillating membrane and the oscillating plate together with the wall form a type of bellows which alternates between a minimum and maximum volume of the blower chamber with each oscillation cycle. This leads to a particularly strong inflow and outflow of fluid into and out of the blower chamber.

character description

Figur 1

eine Explosionsansicht der wichtigsten Komponenten einer Ausführungsform der erfindungsgemäßen Mikropumpe;

Figur 2

eine Schnittansicht durch den Zusammenbau dieser Ausführungsform;

Figur 3

einen schematischen Querschnitt durch diese Ausführungsform zur Verdeutlichung der Fluidpfade;

Figur 4

einen schematischen Querschnitt durch eine Ausführungsform mit axialer Ansaugöffnung;

Figur 5

eine Explosionsansicht einer weiteren Ausführungsform der erfindungsgemäßen Mikropumpe;

Figur 6

eine Schnittansicht durch den Zusammenbau dieser Ausführungsform;

Figur 7

eine Explosionsansicht einer weiteren Ausführungsform der erfindungsgemäßen Mikropumpe;

Figur 8

eine Schnittansicht durch den Zusammenbau dieser Ausführungsform.

The invention is explained below by way of example with reference to figures. while showing

figure 1

an exploded view of the most important components of an embodiment of the micropump according to the invention;

figure 2

a sectional view through the assembly of this embodiment;

figure 3

a schematic cross section through this embodiment to illustrate the fluid paths;

figure 4

a schematic cross section through an embodiment with an axial suction port;

figure 5

an exploded view of a further embodiment of the micropump according to the invention;

figure 6

a sectional view through the assembly of this embodiment;

figure 7

an exploded view of a further embodiment of the micropump according to the invention;

figure 8

a sectional view through the assembly of this embodiment.

In the figure 1 Figure 1 shows an exploded view of the main components of an embodiment of the micropump according to the invention.

Accordingly, the micropump comprises two main units. The first main unit is the swing unit 10.

The oscillating unit 10 includes a disk-shaped piezoelectric actuator 11 which is arranged on an outside of an oscillating membrane 12 (pointing upwards in the figure). A ring 14 of defined thickness is present as the wall for the blower chamber 13 . This is arranged on the oscillating plate 15 which is opposite the inside of the oscillating diaphragm 12 . In the oscillating plate 15 there is a centrally arranged fan opening 16. According to this embodiment, the oscillating plate 15 and the wall (ring 14) are separate components.

Four suspensions 17 are arranged symmetrically to the side of the oscillating plate 15 (only one provided with reference numbers). By means of this, the rest of the swing unit 10 can swing at least, and preferably only, in the vertical direction (in the picture). The distal ends of the suspensions 17 can be inserted into correspondingly shaped receptacles 22 of the housing body 21 (likewise only one is provided with a reference number).

The second main unit is the housing 20.

The housing body 21 includes a recess 23 in which the components of the swing unit 10 can be at least partially accommodated are. Accordingly, there is a gap S between the swing unit 10 and the inside of the housing 20 (cf., for example, the next figure and the one after that), which ensures the necessary freedom of movement of the swing unit 10 . In the case body 21 there are four suction openings 24 (only one is provided with a reference number). In the present case, these initially run radially to the main direction of movement of the swing unit 10, which runs in the vertical direction in the image. After a 90 degree bend (not visible, cf. next figure), they open into the pump chamber 26 .

The housing 20 also includes a housing cover 27 which closes off the interior space, comprising the pump chamber 26 and the half-space H, of the housing 20 . In the present case, the housing cover 27 is provided as a separate component which is connected to the housing body 21 in a gas-tight manner. In the embodiment shown, the housing cover 27 also has a recess (no reference number) in which the components of the swing unit 10 can also be accommodated, at least in part.

In the figure 2 , which shows a sectional view through the assembly of this embodiment, it can be seen that the housing 20 forms a closed space that also covers the piezoelectric actuator 11 and thus protects it from environmental influences. For reasons of clarity, only some of the reference numbers are shown.

The gap S surrounding the swing unit 10 can also be seen, as well as the guidance of the suction openings 24, which lead radially into the housing and, after a 90-degree curve, open perpendicularly into the pump chamber 26.

If the illustrated embodiment is mounted in an inverted position on a panel, none of the openings will be covered or closed by that panel.

According to an embodiment that is not shown, the housing body has only a single, preferably circumferential suction opening. The suction opening then runs parallel to the bottom of the pump chamber below the same and has at least one, but preferably several openings into the pump chamber. In this way, the fluid resistance when flowing in is particularly low.

The figure 3 finally indicates the flow paths of the fluid during operation of the micropump. Here, too, only some of the reference symbols are shown. According to this embodiment, the oscillating plate 15 and the wall are manufactured in an integrated manner. The piezo actuator 11 is arranged gas-tight to the pump chamber 26 . In an intake phase, the swing unit 10 moves in the direction of the arrow 31. Consequently, a negative pressure is generated in the lower half-space, which forms the pump chamber 26. This causes fluid (not shown) to flow in the direction of the arrows 32 through the suction openings 24 into the pump chamber 26 .

In contrast, during a dispensing phase, the swing unit 10 moves in the opposite direction to the arrow 31 . The pressure in the pump chamber 26 rises, which leads to the fluid flowing out through the outlet opening 25 .

As can be seen, the fluid is always conveyed outside of the upper half-space H containing the piezoelectric actuator 11 , which in the present case lies above the oscillating plate 15 . Even if the suspension 17 is designed to be interrupted, the fluid in the half-space H only moves back and forth a little, is therefore not exchanged and therefore also does not "flow", which leads to a reduction in possible impairments of the piezo actuator by the fluid.

The figure 4 shows a schematic cross section through an embodiment with an axial suction opening. Most reference numbers have been omitted for clarity omitted. The embodiment shown differs from that of 3 is that the suction port 24 does not run radially, but extends in the axial direction. Accordingly, it runs approximately parallel to the outlet opening 25 and is located on an underside opposite the swing unit 10 . The lengths of both openings 24, 25 can be the same, but also different, as shown. The intake opening 24 can be in several parts, as in 1 and 2 shown. It can also be designed as a ring opening.

The figure 5 shows an exploded view of a further embodiment of the micropump according to the invention. Here too, as in the following figures, most of the reference numbers have been omitted for reasons of clarity. The figure 6 shows the embodiment of figure 5 in a sectional view. In contrast to the embodiment of 1 and 2 a micropump according to this embodiment has a housing body 21 which is set up to accommodate all moving components including the gap dimensions required for oscillation. The housing cover 27 is essentially flat and has no indentations for the internal components (oscillating unit 10) in particular on the inside.

In figure 5 Also visible is an electrical connection 11B for the piezoelectric actuator 11, which protrudes from the housing 10 after the latter has been assembled ( 6 ).

Figure 7 and Figure 8 show another embodiment of the micropump. After this, the housing 20 is designed in two parts. It comprises a lower part 21A and an upper part 21B; both parts can be connected to one another, for example by means of gluing or welding. The connection is preferably made in the course of the connection of the other housing components such as in particular the cover 27. A two-part lower housing part 21 has the advantage that the suction openings 24 with the Corresponding channels (only one provided with a reference number) can be fluidically shaped more favorably (cf. the channels of 1 and 2 , especially the 90 degree curve).

The embodiment of Figures 7 and 8 also shows a connecting piece of the outlet opening 25 prepared for insertion into a hose.

Reference List

10

swing unit

11

piezo actuator

11B

electrical connection

12

vibrating membrane

13

blower chamber

14

ring

15

swing plate

16

fan opening

17

suspension

20

Housing

21

case body

21A

lower part

21B

top

22

Recording

23

deepening

24

intake port

25

exit port

26

pump chamber

27

housing cover

31:32

Arrow

S

gap

H

space, half space

Claims (11)

1. Micropump for compressible fluids, comprising:

   - a vibration unit (10) surrounded by a gap (S) comprising a disk-shaped piezo actuator (11) disposed on a vibration diaphragm (12), and a vibration plate (15) disposed opposite to an inner side of the vibration diaphragm (12) and having a centrally disposed blower opening (16), as well as a circumferential wall disposed between the vibration diaphragm (12) and the vibration plate (15) so as to form a blower chamber (13);

   - a housing (20) in which the vibration unit (10) can be completely accommodated and in which it is oscillatingly mounted by means of at least one suspension (17), and which has a suction opening (24), as well as an output opening (25) which lies opposite the blower opening (16);

   characterized in that the housing (20)

   - forms a closed half-space (H) which also covers the piezo actuator (11) and thus protects it from environmental influences, and

   - has at least one suction opening (24) arranged radially, or on an underside opposite the vibration unit (10), with a suction channel which leads into a pump chamber (26) located between the vibration plate (15) and the inside of the housing, being different from the suction channel,

   so that during oscillating operation of the piezo actuator (11) the vibration unit (10) can be set into oscillation relative to the housing (20), whereby the compressible fluid can be sucked in through the suction opening (24) and discharged through the output opening (25), wherein the fluid is conveyed outside of the half-space (H) containing the piezo actuator (11).
2. The micropump of claim 1, wherein the housing (20) comprises a housing body (21) and a housing cover (27), and the housing body (21) is adapted to receive all moving components including gaps required for vibration.
3. The micropump of claim 1, wherein the housing (20) comprises a housing body (21) and a housing cover (27), and at least portions of the movable components are disposed in an interior recess of the housing cover (27).
4. Micropump according to any one of claims 1 to 3, wherein the vibration plate (15) and wall are manufactured integrally.
5. Micropump according to any one of claims 1 to 3, wherein the vibration plate (15) and the wall are manufactured as separate components.
6. Micropump according to any one of the preceding claims, wherein the piezo actuator (11) is arranged in a gas-tight manner with respect to the pump chamber (26).
7. A micropump according to any one of the preceding claims, wherein the piezo actuator (11) has a diameter of 5 to 50 mm, and/or a gap (S) between the wall and the inside of the housing (20) is smaller than 0.01 to 1 mm, and the micropump has a total height of 3 to 10 mm.
8. Micropump according to any one of the preceding claims, wherein the diameter of the blower opening (16) is between 0.5 mm and 0.7 mm, and the diameter of the suction opening (s) (24) is between 0.5 mm and 2.5 mm, and the diameter of the outlet opening(s) (25) is between 0.7 and 0.9 mm.
9. A method of delivering a compressible fluid using a micropump as defined in any of the preceding claims, wherein

   - in a suction phase, the piezo actuator (11) is controlled in such a way that it curves against the direction of the blower opening (16), whereby a negative pressure is formed in the blower chamber (13) which is propagated through said blower opening (16) into the pump chamber (26), whereby fluid is drawn in through the suction opening (24) with the suction channel, and

   - in an output phase, the piezo actuator (11) is controlled in such a way that it curves in the direction of the blower opening (16) or goes into a flat rest position, whereby the negative pressure in the blower chamber (13) is reduced or an overpressure is generated, which also propagates through said blower opening (16) into the pump chamber (26), whereby fluid is emitted through the output opening (25),

   so that the vibration unit (10) is caused to oscillate, the fluid being conveyed outside the half-space (H) containing the piezo actuator (11).
10. The method of claim 9, wherein the vibration plate (15) also oscillates in the direction of movement of the piezo actuator (11) .
11. The method of claim 9, wherein the vibration plate (15) oscillates in opposition to the direction of motion of the piezo actuator (11).

Images