(19)
(11) EP 0 331 149 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
14.02.1990 Bulletin 1990/07

(43) Date of publication A2:
06.09.1989 Bulletin 1989/36

(21) Application number: 89103592.5

(22) Date of filing: 01.03.1989
(51) International Patent Classification (IPC)4: D06F 39/00
(84) Designated Contracting States:
DE ES FR GB IT SE

(30) Priority: 02.03.1988 IT 4570888

(71) Applicant: INDUSTRIE ZANUSSI S.p.A.
I-33170 Pordenone (IT)

(72) Inventors:
  • Grandin, Graziello
    I-33170 Pordenone (IT)
  • Bottoset, Roberto
    I-33082 Azzano Decimo Pordenone (IT)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Apparatus for controlling the supply of liquid detergents in a washing machine, particularly a laundry washing machine


    (57) Described is an apparatus for controlling the supply of liquid detergents to the tub of a laundry washer, adapted to establish preselected detergent concentrations in the water admitted to the tub.
    The apparatus comprises an electronic comparator (15) for comparing a preselected reference voltage generated by a control circuit (21) adjusted to a value corresponding to the degree of hardness of the water, to a voltage generated by one of two integrator circuits (17, 18) each having a different time constant, said integrator circuit being selected by an electric contact (10) of the programme timing control unit (6) of the machine for energizing or deenergizing a liquid detergent metering pump (12) via a pilot stage (13) connected to said comparator (15). Also described are two alternative embosiments of the invention.







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