MICROBLOWER

Abstract

A micropump and its use, the micropump including a vibration unit with piezo actuator, which is arranged on an vibration diaphragm, a vibration plate arranged opposite the vibration diaphragm and having a blower opening, as well as a wall arranged between the vibration diaphragm and the vibration plate, so that a blower chamber is formed, and a housing, in which the vibration unit is mounted, with an suction opening, as well as an output opening, which lies opposite the blower opening. The housing forms a closed space and has at least one suction opening arranged radially, or on an underside opposite the vibration unit, with a suction channel leading into a pump chamber located between the vibration plate and the inside of the housing.

Claims

1. A micropump for compressible fluids, the micropump 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); and 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 to oscillate 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. The micropump according to claim 1, wherein the vibration plate (15) and wall are manufactured integrally.

5. The micropump according to claim 1, wherein the vibration plate (15) and the wall are manufactured as separate components.

6. The micropump according to claim 1, wherein the piezo actuator (11) is arranged in a gas-tight manner with respect to the pump chamber (26).

7. The micropump according to claim 1, 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. The micropump according to claim 1, 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 the micropump as defined in claim 1, the method comprising: controlling the piezo actuator (11) in a suction phase, 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 controlling the piezo actuator (11) in an output phase, 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).

Description

DESCRIPTION OF THE DRAWINGS

[0055] The invention is explained below by way of example with the aid of figures, in which:

[0056] FIG. 1 is an exploded view of the main components of an embodiment of the micropump according to the invention;

[0057] FIG. 2 is a sectional view through the assembly of this embodiment;

[0058] FIG. 3 is a schematic cross-section through this embodiment to illustrate the fluid paths;

[0059] FIG. 4 is a schematic cross-section through an embodiment with an axial suction opening;

[0060] FIG. 5 is an exploded view of a further embodiment of the micropump according to the invention;

[0061] FIG. 6 is a sectional view through the assembly of this embodiment;

[0062] FIG. 7 is an exploded view of a further embodiment of the micropump according to the invention; and

[0063] FIG. 8 is a sectional view through the assembly of this embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0064] FIG. 1 shows an exploded view of the main components of one embodiment of the micropump according to the invention.

[0065] Accordingly, the micropump comprises two main units. The first main unit is the vibration unit 10.

[0066] The vibration unit 10 comprises a disk-shaped piezo actuator 11, which is arranged on an outer side (pointing upwards in the picture) of an vibration diaphragm 12. A ring 14 of defined thickness is provided as a wall for the blower chamber 13. This is arranged on the vibration plate 15, which is opposite the inside of the vibration diaphragm 12. A centrally arranged blower opening 16 is located in the vibration plate 15. According to this embodiment, the vibration plate 15 and the wall (ring 14) are separate components.

[0067] Four suspensions 17 are arranged symmetrically at the side of the vibration plate 15 (only one is marked with a reference sign). By means of these, the remaining vibration unit 10 can oscillate at least, and preferably only, in (in the picture) vertical direction. The distal ends of the suspensions 17 can be inserted into correspondingly shaped receptacles 22 of the housing body 21 (likewise only one marked with a reference sign).

[0068] The second main unit is the housing 20.

[0069] The housing body 21 includes a recess 23 in which the components of the vibration unit 10 can be at least partially accommodated. Accordingly, a gap S (cf. e.g. next figure and the figure after next) is present between the vibration unit 10 and the inside of the housing 20, which ensures the required freedom of movement of the vibration unit 10. In the housing body 21 there are four suction openings 24 (only one is marked with a reference sign). These initially run radially to the main direction of movement of the vibration unit 10, which runs in the vertical direction in the figure. After a 90-degree bend (not visible, cf. next figure), they open into the pump chamber 26, from which an output opening 25 leads off centrally, opposite the blower opening 16.

[0070] The housing 20 further comprises a housing cover 27 which closes off the interior volume, comprising pump chamber 26 and half-space H, of the housing 20. In the present embodiment, 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 (without reference sign) in which the components of the vibration unit 10 can also be accommodated at least partially.

[0071] In FIG. 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 piezo actuator 11 and thus protects it from environmental influences. For the sake of clarity, only some of the reference signs are shown.

[0072] The gap S surrounding the vibration unit 10 can also be seen, as well as the direction of the suction openings 24, which lead radially into the housing and, following a 90-degree curve, open vertically into the pump chamber 26.

[0073] If the depicted embodiment is mounted on a panel in an inverted position, none of the openings will be covered or closed by this panel.

[0074] According to an embodiment 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 latter, and has at least one, but preferably several, openings into the pump chamber. In this way, the fluid resistance during inflow is particularly low.

[0075] Finally, FIG. 3 indicates the flow paths of the fluid during operation of the micropump. Again, only some of the reference signs are shown. According to this embodiment, the vibration plate 15 and the wall are manufactured in an integrated manner. The piezo actuator 11 is arranged gas-tight with respect to the pump chamber 26. In a suction phase, the vibration unit 10 moves in the direction of arrow 31. Consequently, a negative pressure is generated in the lower half-space that forms the pump chamber 26. This causes fluid (not shown) to flow in the direction of arrows 32 through the suction openings 24 into the pump chamber 26.

[0076] In an output phase, on the other hand, the vibration unit 10 moves in the direction opposite to the direction of arrow 31. This induces an increase in pressure in the pumping chamber 26, which results in fluid flowing out through the output opening 25.

[0077] As can be seen, the fluid is at all times conveyed outside the upper half-space H containing the piezo actuator 11, which in the present case lies above the vibration plate 15. Even if the suspension 17 is non-continuous, the fluid only moves back and forth a little in the half-space H, i.e. it is not exchanged and therefore does not “flow”, which leads to a reduction of possible impairments of the piezo actuator by the fluid.

[0078] FIG. 4 shows a schematic cross-section of an embodiment with axial suction opening. Most reference signs have been omitted for clarity. The embodiment shown differs from that of FIG. 3 in that the suction opening 24 does not run radially, but extends in the axial direction. Accordingly, it runs approximately parallel to the output opening 25, and is located on an underside opposite the vibration unit 10. The lengths of both openings 24, 25 may be the same, but may also be different, as shown. The suction opening 24 can be multi-part, as shown in FIG. 1 and FIG. 2. It may also be configured as an annular opening.

[0079] FIG. 5 shows an exploded view of a further embodiment of the micropump according to the invention. Here, as in the following figures, most of the reference signs have been omitted for reasons of clarity. FIG. 6 shows a sectional view of the embodiment of FIG. 5. In contrast to the embodiment of FIG. 1 and FIG. 2, a micropump according to this embodiment has a housing body 21 which is designed to accommodate all moving components including the gaps required for vibration. The housing cover 27 has a substantially flat design and, in particular, does not have any recesses on the inside for the internal components (vibration unit 10).

[0080] Also visible in FIG. 5 is an electrical connection 11B for the piezo actuator 11, which protrudes from the housing 10 after it has been assembled (FIG. 6).

[0081] FIG. 7 and FIG. 8 show a further embodiment of the micropump. According to this embodiment, the housing 20 is made of two parts. It comprises a lower part 21A and an upper part 21B, both parts can be joined together, for example, by means of bonding or welding. Preferably, the connection is made in the course of connecting 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 marked with a reference sign) can be shaped in a more fluidically favorable manner (cf. the channels of FIG. 1 and FIG. 2, in particular the 90-degree curve).

[0082] The embodiment of FIG. 7 and FIG. 8 also shows a port of the output opening 25 prepared for insertion into a hose.

LIST OF REFERENCE SIGNS

[0083] 10 vibration unit [0084] 11 piezo actuator [0085] 11B electrical connection [0086] 12 vibration diaphragm [0087] 13 blower chamber [0088] 14 ring [0089] 15 vibration plate [0090] 16 blower opening [0091] 17 suspension [0092] 20 housing [0093] 21 housing body [0094] 21A bottom part [0095] 21B top part [0096] 22 receptacle [0097] 23 recess [0098] 24 suction opening [0099] 25 output opening [0100] 26 pump chamber [0101] 27 housing cover [0102] 31,32 arrow [0103] S gap [0104] H space, half-space