(19)
(11) EP 0 342 484 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.10.1990 Bulletin 1990/40

(43) Date of publication A2:
23.11.1989 Bulletin 1989/47

(21) Application number: 89108330.5

(22) Date of filing: 09.05.1989
(51) International Patent Classification (IPC)4: F04D 29/66, F24F 13/24
(84) Designated Contracting States:
BE DE ES FR

(30) Priority: 16.05.1988 IT 2059588

(71) Applicant: RIELLO CONDIZIONATORI S.p.A.
I-37040 Bevilacqua Verona (IT)

(72) Inventor:
  • Riello, Valerio Giordano
    I-37045 Legnago (Verona) (IT)

(74) Representative: Münzhuber, Robert, Dipl.-Phys. et al
Patentanwalt Rumfordstrasse 10
D-80469 München
D-80469 München (DE)


(56) References cited: : 
   
       


    (54) Very noiseless motor driven centrifugal fan


    (57) The motor driven centrifugal fan (10) according to the present invention has the inner surface (18) of the volute (12) and possibly also the inner surfaces of the sidewalls (13) laterally defining the volute which are roughened.
    The roughness can comprise projections or recesses of irregular shape, for example of orange-peel type, or of regular shape, for exam­ple regular polygons or circles which can be arranged along parallel lines which are or not offset from each other.







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