Low-water-consumption rinsing and/or washing device, and dishwashing machine featuring such a device

Abstract

A spray arm assembly for a dishwashing machine includes at least one arm rotationally mounted about an axis, the arm including an internal cavity for receiving a pressurized service fluid and being provided with a plurality of spraying nozzles for spraying service fluid from said arm in the form of spray jets. The arm is shaped so that its opposite ends radially extend from the rotation axis in a manner diametrically opposite to each other about the rotation axis. The spraying nozzles are numbered, sized and positioned such that a total flow rate of service fluid delivered in use by the spraying nozzles at each concentric nozzle location circumference traced about the rotation axis of the arm during a complete rotation of the arm increases as a function of the radius of said nozzle location circumference.

1 . A rinsing and/or washing device for a dishwashing machine, comprising at least one arm rotationally mounted about a generally vertical axis (A) in a washing chamber of the dishwashing machine, the arm delimiting a cavity therein connected in use to delivering means of a pressurized service fluid and being provided with a plurality of spraying nozzles arranged and oriented, in use, for spraying towards dishes to be washed, the spraying nozzles spaced along a length of the arm and communicating with the internal cavity ( 22 ) of the arm, so as to determine in use exiting of service fluid from the arm in form of jets directed against dishes; wherein said arm is shaped so that its opposite ends radially and overhangingly extend from the rotation axis, in a manner diametrically opposite to the rotation axis itself; characterized in that, in combination, the number, the size and the position of the spraying nozzles is such that the total flow rate of service fluid delivered in use by the spraying nozzles at each concentric nozzle location circumference traced about the rotation axis of the arm during a complete rotation of the arm is an increasing function of the radius of said nozzle location circumference. 
   
   
       2 . A device according to  claim 1 , characterized in that the total flow rate of service fluid delivered in use by the spraying nozzles at each concentric nozzle location circumference traced about the rotation axis of the arm during the complete rotation of the arm increases in an essentially linear manner with the radius of said nozzle location circumference. 
   
   
       3 . A device according to  claim 2 , characterized in that said arm has an assembly portion for securing it to said rotation axis arranged essentially on the middle line of the arm, so that opposite longitudinal portions of the arm, provided with said spraying nozzles and ending with said opposite ends of the arm, protrude in use in an essentially symmetric manner from the assembly portion in radial direction with respect to the rotation axis. 
   
   
       4 . A device according to  claim 3 , characterized in that said spraying nozzles are arranged along said opposite longitudinal portions of the arm so that at least one spraying nozzle of a first of said opposite longitudinal portions of the arm is arranged in a radially symmetric position with respect to at least one spraying nozzle of a second of said longitudinal portions of the arm, so that said at least one spraying nozzle of said first longitudinal portion of the arm traces in use the same nozzle location circumference traced in use by said at least one spraying nozzle of said second longitudinal portion of the arm. 
   
   
       5 . A device according to  claim 4 , characterized in that said arm is provided with first spraying nozzles adapted to deliver in use a first predetermined flow rate of service fluid; and with second spraying nozzles adapted to deliver in use a second predetermined flow rate of service fluid, smaller than said first predetermine flow rate. 
   
   
       6 . A device according to  claim 5 , characterized in that said arm is provided only with said first and second spraying nozzles. 
   
   
       7 . A device according to  claim 6 , characterized in that the first of said opposite longitudinal portions of the arm carries one second spraying nozzle arranged at a predetermined radial distance from the assembly portion so as to trace in use a first nozzle location circumference about said rotation axis, and a pair of first spraying nozzles arranged in tandem at respective radial distances from the assembly portion so that each of them respectively traces in use a second and a third nozzle location circumference about said rotation axis. 
   
   
       8 . A device according to  claim 7 , characterized in that the second longitudinal portion of the arm, opposite to the first, carries:
 one first spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use a fourth nozzle location circumference about said rotation axis;   one second spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use said second nozzle location circumference about said rotation axis; and   one first spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use said third nozzle location circumference about said rotation axis.   
   
   
       9 . A device according to  claim 8 , characterized in that said fourth nozzle location circumference has a radius greater than that of said first nozzle location circumference and smaller than the radius of said second nozzle location circumference. 
   
   
       10 . A device according to  claim 9 , characterized in that said arm is provided with reaction thrust generating means to determine in use the rotation about said axis. 
   
   
       11 . A spray arm assembly for a dishwashing machine, comprising at least one arm rotationally mounted about an axis, the arm including an internal cavity for receiving a pressurized service fluid and being provided with a plurality of spraying nozzles for spraying service fluid from said arm in the form of spray jets; wherein said arm is shaped so that its opposite ends radially extend from the rotation axis in a manner diametrically opposite to each other about the rotation axis; characterized in that, the spraying nozzles are numbered, sized and positioned such that a total flow rate of service fluid delivered in use by the spraying nozzles at each concentric nozzle location circumference traced about the rotation axis of the arm during a complete rotation of the arm increases as a function of the radius of said nozzle location circumference. 
   
   
       12 . The spray arm assembly according to  claim 11 , characterized in that the total flow rate of service fluid delivered in use by the spraying nozzles at each concentric nozzle location circumference traced about the rotation axis of the arm during the complete rotation of the arm increases in an essentially linear manner with the radius of said nozzle location circumference. 
   
   
       13 . The spray arm assembly according to  claim 12 , characterized in that said arm has a central assembly portioned for securing it to a dishwashing machine, said rotation axis extending through said central assembly so that opposite longitudinal portions of the arm, provided with said spraying nozzles and ending with said opposite ends of the arm, protrude in use in an essentially symmetric manner from the assembly portion in radial direction with respect to the rotation axis. 
   
   
       14 . The spray arm assembly according to  claim 13 , characterized in that said spraying nozzles are arranged along said opposite longitudinal portions of the arm so that at least one spraying nozzle of a first of said opposite longitudinal portions of the arm is arranged in a radially symmetric position with respect to at least one spraying nozzle of a second of said longitudinal portions of the arm, so that said at least one spraying nozzle of said first longitudinal portion of the arm traces in use the same nozzle location circumference traced in use by said at least one spraying nozzle of said second longitudinal portion of the arm. 
   
   
       15 . The spray arm assembly according to  claim 14 , characterized in that said arm is provided with first spraying nozzles adapted to deliver in use a first predetermined flow rate of service fluid; and with second spraying nozzles adapted to deliver in use a second predetermined flow rate of service fluid, smaller than said first predetermine flow rate. 
   
   
       16 . The spray arm assembly according to  claim 15 , characterized in that the first of said opposite longitudinal portions of the arm carries:
 one second spraying nozzle arranged at a predetermined radial distance from the assembly portion so as to trace in use a first nozzle location circumference about said rotation axis, and   a pair of first spraying nozzles arranged in tandem at respective radial distances from the assembly portion so that each of them respectively traces in use a second and a third nozzle location circumference about said rotation axis.   
   
   
       17 . A device according to  claim 16 , characterized in that the second longitudinal portion of the arm, opposite to the first, carries:
 one first spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use a fourth nozzle location circumference about said rotation axis;   one second spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use said second nozzle location circumference about said rotation axis; and   one first spraying nozzle arranged at a radial distance from the assembly portion so as to trace in use said third nozzle location circumference about said rotation axis.   
   
   
       18 . A device according to  claim 17 , characterized in that said fourth nozzle location circumference has a radius greater than that of said first nozzle location circumference and smaller than the radius of said second nozzle location circumference. 
   
   
       19 . A dishwashing machine including the spray arm assembly of  claim 11 , comprising:
 a wash chamber including a dish receiving area;   the spray arm assembly of  claim 11  mounted for rotation within the wash chamber with the rotation axis essentially vertical;   a service fluid delivery system connected to deliver service fluid to the internal cavity of the arm.   
   
   
       20 . The dishwashing machine of  claim 19  wherein the spray arm assembly is fluid-tightly mounted on an inlet head within the washing chamber.