Washing appliance with improved control of circulation pump and inlet valve

Abstract

A washing appliance is provided, including a tub configured to house items to be washed; an inlet valve configured to be operated in an open condition for causing washing fluid to be loaded into the tub and in a closed condition for preventing washing fluid to be fed to the appliance; a circulation pump configured to circulate the washing fluid in the tub during a washing cycle; a control unit configured to determine an operative state of the circulation pump between a saturation state indicative that sufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump, and a starvation state indicative that insufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump. The control unit is further configured to receive an indication of a target speed for the circulation pump based on a user-selected washing cycle and/or on a phase of the user-selected washing cycle; control the current speed of the circulation pump based on the target speed, the inlet valve condition, the operative state of the circulation pump; operate the inlet valve based on: the target speed, the current speed of the circulation pump, and the operative state of the circulation pump.

1 - 21 . (canceled) 
     
     
         22 . A washing appliance comprising:
 a tub configured to house items to be washed;   an inlet valve configured to be operated in an open condition for causing washing fluid to be loaded into the tub and in a closed condition for preventing washing fluid to be fed to the appliance;   a circulation pump configured to circulate the washing fluid in the tub during a washing cycle;   a control unit configured to determine an operative state of the circulation pump between a saturation state indicative that sufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump, and a starvation state indicative that insufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump, wherein the control unit is further configured to:
 receive an indication of a target speed for the circulation pump based on a user-selected washing cycle and/or on a phase of the user-selected washing cycle; 
 control the current speed of the circulation pump based on:
 the target speed; 
 the inlet valve condition; and 
 the operative state of the circulation pump; and 
 
 operate the inlet valve based on:
 the target speed; 
 the current speed of the circulation pump; and 
 the operative state of the circulation pump. 
 
   
     
     
         23 . The washing appliance of  claim 22 , wherein the control unit is configured to control the current speed of the circulation pump by:
 causing the current speed of the circulation pump to increase towards the target speed with a first speed increase rate if both conditions a) and b) are met:
 a) a starvation state of the circulation pump is determined before the current speed of the circulation pump reached the target speed; and 
 b) the inlet valve is in the open condition; and 
   causing the current speed of the circulation pump to increase towards the target speed with a second speed increase rate lower than the first speed increase rate.   
     
     
         24 . The washing appliance of  claim 23 , wherein the control unit is configured to control the current speed of the circulation pump by causing the current speed of the circulation pump to be decreased if condition a) is met while condition b) is not met. 
     
     
         25 . The washing appliance of  claim 23 , wherein the control unit is configured to control the current speed of the circulation pump by causing the current speed of the circulation pump to increase towards the target speed with the second speed increase rate if, in addition to having both conditions a) and b) met, no saturation state of the circulation pump is determined during a predetermined time period after the determination of a starvation state of the circulation pump. 
     
     
         26 . The washing appliance of  claim 23 , wherein the control unit is configured to control the current speed of the circulation pump by causing the current speed of the circulation pump to increase towards the target speed with a third speed increase rate lower than the first speed increase rate and higher than the second speed increase rate if the speed of the circulation pump reached the target speed before a starvation state of the circulation pump is determined. 
     
     
         27 . The washing appliance of  claim 26 , wherein the control unit is configured to control the current speed of the circulation pump by causing the current speed of the circulation pump to increase towards the target speed with the third speed increase rate if, in addition to having condition a) met, a saturation state of the circulation pump is determined during the predetermined time period. 
     
     
         28 . The washing appliance of  claim 22 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if both conditions c) and d) are met:
 c) a saturation state of the circulation pump is determined; and 
 d) the current speed of the circulation pump is lower than the target speed, and wherein the control unit is configured to delay the switch of the inlet valve from the open condition to the closed condition by a delay interval if, in addition to having both conditions c) and d) met, the difference between the target speed and the current speed of the circulation pump is higher than a speed threshold. 
   
     
     
         29 . The washing appliance of  claim 28 , wherein a duration of the delay interval is based on the difference between the target speed and the current speed of the circulation pump. 
     
     
         30 . The washing appliance of  claim 28 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if, in addition to having condition c) met, condition d) is not met.   
     
     
         31 . The washing appliance of  claim 28 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if both conditions c) and d) are not met.   
     
     
         32 . The washing appliance of  claim 28 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the closed condition to the open condition if, in addition to having condition d) met, condition c) is not met.   
     
     
         33 . The washing appliance of  claim 22 , wherein the target speed comprises a first target speed and a second target speed, and wherein:
 the control unit is configured to control the current speed of the circulation pump based on:
 the first target speed; 
 the inlet valve condition; and 
 the operative state of the circulation pump; and 
   the control unit is configured to operate the inlet valve based on:
 the second target speed; 
 the current speed of the circulation pump; and 
 the operative state of the circulation pump. 
   
     
     
         34 . The washing machine of  claim 22 , wherein the washing machine is a dishwasher comprising:
 at least one basket provided in the tub for accommodating the items to be washed;   a set of spray devices for receiving washing fluid from the circulation pump and for spraying the received washing fluid into the tub.   
     
     
         35 . The washing appliance of  claim 22 , wherein the target speed depends on a user-selected washing cycle being carried out by the washing appliance and/or by a phase of the user-selected washing cycle being carried out by the washing appliance. 
     
     
         36 . A washing appliance comprising:
 a tub configured to house items to be washed;   an inlet valve operable to be selectively switched between an open condition for causing washing fluid to be loaded into the tub and a closed condition for preventing washing fluid be fed to the appliance;   a circulation pump configured to circulate the washing fluid in the tub during a washing cycle;   a control unit configured to determine an operative state of the circulation pump between (i) a saturation state indicative that sufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump, and (ii) a starvation state indicative that insufficient washing fluid is present in the tub to prevent air from being drawn out by the circulation pump, wherein the control unit is further configured to receive an indication of a current value of a speed of the circulation pump and an indication of a target speed for the circulation pump, and to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if the following two conditions e) and f) are both met:
 e) a saturation state of the circulation pump is determined; and 
 f) the current value of the speed of the circulation pump is lower than the target speed, and 
 
   
       wherein the control unit is configured to delay the switch of the inlet valve from the open condition to the closed condition by a delay interval if, in addition to having both conditions e) and f) met, the difference between the target speed and the current value of the seed of the circulation pump is higher than a speed threshold. 
     
     
         37 . The washing appliance of  claim 36 , wherein a duration of the delay interval is based on the difference between the target speed and the current value of the speed of the circulation pump. 
     
     
         38 . The washing appliance of  claim 36 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if, in addition to having condition e) met, condition f) is not met.   
     
     
         39 . The washing appliance of  claim 36 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the open condition to the closed condition if both conditions e) and f) are not met.   
     
     
         40 . The washing appliance of  claim 36 , wherein the control unit is configured to operate the inlet valve by:
 causing the inlet valve to switch from the closed condition to the open condition if, in addition to having condition f) met, condition e) is not met.   
     
     
         41 . The washing appliance of  claim 36 , wherein the target speed depends on a user-selected washing cycle being carried out by the washing appliance and/or by a phase of the user-selected washing cycle being carried out by the washing appliance.