Method for washing laundry in a spray washing machine

Abstract

A method for washing laundry in a washing machine, preferably a horizontal axis washing machine, having a drum rotatably mounted in a tub, a recirculation pump for recirculating a washing liquid on the laundry and a heating device in the tub for heating washing liquid, comprises increasing the drum speed up to a predetermined low spin speed while recirculation pump is switched off in order to increase water level in the tub and then switching on the heating device.

1 - 15 . (canceled) 
     
     
         16 . A method for washing laundry in a washing machine, preferably a horizontal axis washing machine, comprising a drum rotatably mounted in a tub, a recirculation pump for recirculating a washing liquid on the laundry and a heating device for heating washing liquid, the method comprising: increasing the drum speed up to a predetermined low spin speed while the recirculation pump is switched off in order to increase a water level in the tub and then switching on the heating device. 
     
     
         17 . The method according to  claim 16 , wherein the heating device is switched on for a predetermined period of time. 
     
     
         18 . The method according to  claim 17 , wherein said predetermined period of time is based on the actual energy to be transferred to laundry. 
     
     
         19 . The method according to  claim 18 , wherein said period of time is calculated according to the formula: 
       
         
           
             
               
                 t 
                 = 
                 
                   
                     
                       
                         
                           
                             
                               
                                 ( 
                                 
                                   
                                     Ml 
                                     * 
                                     A 
                                   
                                   + 
                                   Mwl 
                                 
                                 ) 
                               
                               * 
                               Cw 
                               * 
                               
                                 ( 
                                 
                                   Tt 
                                   - 
                                   
                                     T 
                                      
                                     
                                         
                                     
                                      
                                     2 
                                   
                                 
                                 ) 
                               
                             
                             + 
                           
                         
                       
                       
                         
                           
                             ( 
                             
                               
                                 Ml 
                                 * 
                                 Cl 
                                 * 
                                 
                                   ( 
                                   
                                     Tt 
                                     - 
                                     
                                       T 
                                        
                                       
                                           
                                       
                                        
                                       1 
                                     
                                   
                                   ) 
                                 
                               
                               + 
                               
                                 
                                   ( 
                                   
                                     Tt 
                                     - 
                                     
                                       T 
                                        
                                       
                                           
                                       
                                        
                                       1 
                                     
                                   
                                   ) 
                                 
                                 * 
                                 k 
                               
                             
                           
                         
                       
                     
                     
                       V 
                       2 
                     
                   
                   * 
                   R 
                 
               
               , 
             
           
         
         where Ml=mass of laundry in the tub, 
         A=specific absorption of the laundry, 
         Mwl=mass of free water, 
         Cw=thermal capacity of water, 
         Tt=target temperature of the load+water, 
         T2=temperature of water loaded in the tub, 
         Cl=thermal capacity of load, 
         T1=ambient temperature, 
         K=experimental coefficient for taking care of heat loss, 
         R=resistance of the heater in the tub, 
         V=voltage of electrical current used by the heater. 
       
     
     
         20 . The method according to claim  1 , wherein said low spin speed is comprised between 80 and 120 rpm. 
     
     
         21 . The method according to claim  1 , wherein the low spin speed is maintained for an overall time comprised between 10 and 50 seconds. 
     
     
         22 . The method according to claim  1 , wherein during the phase in which the heating device is switched on, the drum is rotated, at least intermittently, at a tumbling speed. 
     
     
         23 . The method according to  claim 21 , wherein the tumbling speed is comprised between 10 and 70 rpm. 
     
     
         24 . The method according to claim  1 , wherein after the heating device is switched off, the drum is rotated at a second low spin speed for a predetermined period of time. 
     
     
         25 . The method according to  claim 24 , wherein the second low spin speed is substantially identical to the first spin speed. 
     
     
         26 . A washing machine, preferably horizontal axis washing machine, comprising:
 a tub,   a drum rotatably mounted in a tub,   a recirculation pump for recirculating a washing liquid through the drum,   a motor rotating the drum,   a heating device for heating washing liquid, and   a control unit adapted to drive the motor in order to increase the drum speed up to a predetermined low spin speed while the recirculation pump is switched for increasing a water level in the tub and assuring that the heating device is fully submerged.   
     
     
         27 . The washing machine according to  claim 26 , wherein the control unit is adapted to drive the heating device for a predetermined period of time. 
     
     
         28 . The washing machine according to  claim 27 , wherein said predetermined period of time is calculated by the control unit on the basis if the actual energy to be transferred to laundry. 
     
     
         29 . The washing machine according to  claim 26 , wherein the control unit is adapted to drive the drum, at least intermittently, at a tumbling speed while said heating device is switched on. 
     
     
         30 . The washing machine according to  claim 26 , wherein the control unit is adapted to drive the motor, after the heating device is switched off, so that the drum is rotated at a second low spin speed for a predetermined period of time.