Laundry washing machine and method for operating the laundry washing machine

Abstract

A laundry washing machine having a washing tub external to a washing drum configured to receive the laundry to be washed, a recirculation system having a first duct to circulate liquid into a first region of the washing tub and a second duct to circulate liquid into a second region of the washing tub. The recirculation system comprises a recirculation pump operable in a first direction of rotation and in a second direction of rotation opposite to the first direction. The recirculation pump is operated in the first direction to circulate liquid in the first duct and is operated in the second direction to circulate liquid in the second duct.

1 . A laundry washing machine comprising:
 a washing drum configured to receive laundry to be washed;   a washing tub external to the washing drum;   a water supply system configured to convey water to the washing tub;   a recirculation system configured to drain liquid from a bottom of the washing tub and to re-admit the liquid into a first region and a second region of the washing tub, the recirculation system comprising:   a first duct terminating at the first region wherein the liquid may circulate to reach the washing tub;   a second duct terminating at the second region wherein the liquid may circulate to reach the washing tub; and   a recirculation pump operable in a first direction of rotation and in a second direction of rotation opposite to the first direction, the recirculation pump comprising a pump chamber having an inlet connected to the bottom of the washing tub and an outlet arrangement connected to the first duct and the second duct, wherein the first duct and the second duct are configured so that the liquid in the first duct requires a first pressure to reach the washing tub which is lower than a second pressure required for the liquid in the second duct to reach the washing tub, and the recirculation pump is configured to be operated in the first direction to circulate liquid in the first duct to reach the washing tub and operated in the second direction to circulate liquid in the second duct to reach the washing tub.   
     
     
         2 . The washing machine according to  claim 1 , wherein the outlet arrangement comprises a first outlet from the pump chamber to the first duct and a second outlet from the pump chamber to the second duct. 
     
     
         3 . The washing machine according to  claim 2 , wherein the first outlet and the second outlet are located at a body portion of the recirculation pump. 
     
     
         4 . The washing machine according to  claim 2 , wherein the first outlet is tangentially arranged with respect to the pump chamber and/or the second outlet is tangentially arranged with respect to the pump chamber. 
     
     
         5 . The washing machine according to  claim 2 , wherein the first outlet is parallel to the second outlet. 
     
     
         6 . The washing machine according to  claim 1 , wherein the outlet arrangement comprises a common outlet portion from the pump chamber and a bifurcation having a first portion leading to the first duct and a second portion leading to the second duct. 
     
     
         7 . The washing machine according to  claim 6 , wherein the common outlet portion and the bifurcation comprise a body portion of the recirculation pump. 
     
     
         8 . The washing machine according to  claim 1 , wherein the recirculation pump is a fixed speed pump. 
     
     
         9 . The washing machine according to  claim 1 , wherein the recirculation pump is a variable speed pump. 
     
     
         10 . The washing machine according to  claim 1 , wherein the first region is a bottom part of the washing tub. 
     
     
         11 . The washing machine according to  claim 1 , wherein the second region is an upper part of the washing tub. 
     
     
         12 . The washing machine according to  claim 1 , wherein the first duct defines a first volume and the second duct defines a second volume, wherein the first volume is lower than the second volume. 
     
     
         13 . A method for operating a laundry washing machine comprising:
 a washing drum configured to receive laundry to be washed;   a washing tub external to the washing drum;   a water supply system configured to convey water to the washing tub;   a recirculation system configured to drain liquid from the bottom of the washing tub and to re-admit the liquid into a first region and a second region of the washing tub, the recirculation system comprising:
 a first duct terminating at the first region wherein the liquid may circulate to reach the washing tub; 
 a second duct terminating at the second region wherein the liquid may circulate to reach the washing tub; 
   a recirculation pump operable in a first direction of rotation and in a second direction of rotation opposite to the first direction, the recirculation pump comprising a pump chamber having an inlet connected to the bottom of the washing tub and an outlet arrangement connected to the first duct and the second duct, wherein the first duct and the second duct are configured so that the liquid in the first duct requires a first pressure to reach the washing tub which is lower than a second pressure required for the liquid in the second duct to reach the washing tub;   wherein the method comprises:
 operating the recirculation pump in the first direction to circulate the liquid in the first duct to reach the washing tub; and 
 operating the recirculation pump in the second direction to circulate the liquid in the second duct to reach the washing tub. 
   
     
     
         14 . The method according to  claim 13 , wherein the recirculation pump is operated in the first direction to circulate liquid only in the first duct. 
     
     
         15 . A method according to  claim 13 , characterized wherein the recirculation pump is operated in the second direction to circulate liquid mainly in the second duct.