EP0568902A2
Expired / Lapsed
EP
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Micropump avoiding microcavitation
Assignee: Westonbridge International Ltd
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Filing: 1993-04-27
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Granted: —
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Expires: 2013-04-27
Abstract
Abstract A micropump (1) which is reciprocatingly driven by a membrane (18) into subsequent outwards and inwards bulging movements, in response to the application of an excitation voltage to a piezoelectric microactuator 9. The application of the excitation voltage follows a wave form which includes rapidly ascending ramps which produce rapid decrease of the volume of the pump chamber, and slowly descending ramps which produce sufficiently moderate rates of increase of the volume of the pump chamber in order to avoid microcavitation. <IMAGE>
Inventors
- 👤 M. Ary Saaman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 13:29
CPC Classifications
F; F04; F04B; F04B43/00; F04B43/02; F04B43/04; F04B43/043; F04B43/046
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
201 words
A micropump comprising a structural intermediate member (3) which is at least partially sandwiched between an upper plate (2), and a lower support plate (4), at least one of said upper plate (2) and said structural member (3) forming a membrane (18), which structural member defines at least one valve element (7, 8) and a pump chamber (10), said membrane (18) closing said pump chamber and carrying a microactuator (9) susceptible of causing said membrane to carry out a reciprocating outwards and inwards bulging in response of an excitation voltage applied to said microactuator from a control unit for said actuator and wherein the outwards and inwards bulging movements of said membrane increase and decrease respectively the volume of said pump chamber 10 and are controlled by the variation of said excitation voltage which comprises an ascending ramp for one of the thrust phase or the suction phase of the micropump and a descending ramp for the other one of said two phases, characterized in that the voltage variation of the descending ramp is selected such as to produce an outwards bulging of the membrane for the starting of the suction phase which is sufficiently moderated in order to avoid microcavitation.
Claim 2
Dependent Claim
17 words
The pump of claim 1, wherein the ascending ramp of the excitation voltage lasts about 1 ms.
Claim 3
Dependent Claim
19 words
The pump of any one of claims 1 or 2, wherein the descending ramps last at least 10 ms.
Claim 4
Dependent Claim
45 words
The pump of any one of claims 1-3, wherein the descending ramp has a linear shape starting from the end of a holding phase 22 during which the voltage is kept at a maximum level, until the beginning of the next following ascending ramp 19.
Claim 5
Dependent Claim
39 words
The pump of any one of claims 1-3, wherein the descending ramp is linear and shorter than the time period between the end 24 of the holding phase 22 and the beginning 23 of the next following ascending ramp.
Claim 6
Dependent Claim
17 words
The pump of any one of claims 1-3, wherein the descending ramp 25' follows an exponential curve.
Claim 7
Dependent Claim
20 words
The pump of any one of claims 1-6, wherein the maximum excitation voltage is between 100 V and 150 V.
Claim 8
Independent Claim
104 words
A method of operating a micropump having a pump chamber which is closed by a pump membrane, which membrane is driven by a piezoelectric microactuator, comprising the following steps: - providing a micropump and a controllable voltage source; - applying voltage from said voltage source to said piezoelectric microactuator, whereby said applied voltage comprises alternating rapidly ascending ramps and slower descending ramps, such as to; - rapidly decreasing the volume of said pump chamber in response to said rapidly ascending ramps; and - sufficiently slowly increasing the volume of said pump chamber in response to said slowly descending ramps in order to avoid microcavitation.
Claim 9
Dependent Claim
23 words
The method of claim 8 wherein the ascending ramps last about 1 ms and the descending ramps last about 10 to 100 ms.
References Cited (Backward Citations)
No citation records indexed.
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