(19)
(11) EP 0 568 902 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.03.1994 Bulletin 1994/09

(43) Date of publication A2:
10.11.1993 Bulletin 1993/45

(21) Application number: 93106828.2

(22) Date of filing: 27.04.1993
(51) International Patent Classification (IPC)5: F04B 43/04
(84) Designated Contracting States:
AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

(30) Priority: 02.05.1992 GB 9209593

(71) Applicant: WESTONBRIDGE INTERNATIONAL LIMITED
Ballsbridge, Dublin 4 (IE)

(72) Inventor:
  • Saaman, M. Ary
    CH-1004 Lausanne (CH)

(74) Representative: Micheli & Cie 
Rue de Genève 122, Case Postale 61
1226 Genève-Thonex
1226 Genève-Thonex (CH)


(56) References cited: : 
   
       


    (54) Micropump avoiding microcavitation


    (57) 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.






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