Device for dispensing at least one washing agent in a dishwashing machine

Abstract

The dispensing device includes a support body adapted to be mounted on the side of that door of the machine which is facing the washing chamber, in a position such that in the operation this body is periodically flushed, at least in part, by a flow of washing liquid emitted by at least one spraying rotor. In the support body there is incorporated an electrically conducting member whose electric capacitance with respect to earth is variable by the effect of the flow of washing liquid which periodically impinges onto the body; a detection and processing device being connected to the conducting member and being predisposed for detecting the variations of the electric capacitance of said conducting member with respect to earth and for correlating in a predetermined manner said variations with the operation of the spraying rotor.

1 . A device for dispensing at least one washing agent in a dishwashing machine having a washing chamber which is closed by a door and in which there is mounted at least one spraying rotor for spraying a washing liquid; the dispensing device comprising a support body adapted to be mounted on the side of the door facing the washing chamber, in a position such that in the operation said body is periodically flushed, at least in part, by a flow of washing liquid emitted by said spraying rotor;
 wherein in said support body there is incorporated an electrically conducting member whose electric capacitance with respect to earth is variable by the effect of the flow of washing liquid which periodically impinges onto said body; detection and processing circuit means, coupled to earth, being connected to said conducting member and being predisposed for detecting the variations of the electric capacitance of said conducting member with respect to earth and for correlating in a predetermined manner said variations with the operation of said spraying rotor.   
     
     
         2 . A dispensing device according to  claim 1 , wherein in said support body there is defined at least one receptacle intended to receive an amount of a washing agent, and to which there is attached a further electrically conducting member which is likewise incorporated in the support body and whose electrical capacitance with respect to earth is variable as a function of the quantity or level of the washing agent in said receptacle, and in which detection and processing circuit means are coupled to said further conducting member and are predisposed to detect variations of the electrical capacitance thereof with respect to earth. 
     
     
         3 . A dispensing device according to  claim 1 , wherein the detection circuit means are predisposed to apply to the or each conducting member a respective high-frequency electric excitation signal and to acquire from the or each conducting member a corresponding low-frequency electrical response signal influenced by the respective electrical capacitance with respect to earth, and to analyse in predetermined ways said or each response signal. 
     
     
         4 . A dispensing device according to  claim 1 , wherein said at least one spraying rotor is rotatable about an essentially vertical axis, and said conducting member has an elongate shape and extends in such a way that in the operation it is at least approximately horizontal. 
     
     
         5 . A dispensing device according to  claim 2 , wherein said at least one further conducting member has an elongate shape, and extends in such a way that in the operation it is at least approximately vertical.