Washing machine with water control and associated method

Abstract

An automatic washing machine with water level control and associated method. In one embodiment, the washing machine comprises a tub for receiving a load of clothes, a water level sensor taking water level measurements during a water fill stage, and a controller. The controller controls a water valve that introduces water into the washing machine. The controller comprises a timer, a memory and a microprocessor. The microprocessor accesses a signature fill rate of the washing machine when unloaded, receives water level measurements from the sensor during the fill stage, and determines a measured fill rate. The microprocessor compares the measured fill rate to the signature fill rate and shut off the water valve when the measured fill rate is substantially equal to the signature fill rate.

1 . A method for controlling a water fill level of a washing machine, the method comprising: 
 loading the washing machine with a wash load;    initiating a water fill stage;    counting the water fill time;    measuring the water level;    determining a measured fill rate from the measured water level and water fill time;    comparing the measured fill rate to a signature fill rate characteristic of the washing machine when unloaded; and    terminating the water fill stage when the measured fill rate is equal to the signature fill rate.    
   
   
       2 . The method of  claim 1 , wherein measuring the water level includes obtaining water level measurements using a water level sensor.  
   
   
       3 . The method of  claim 1 , further comprising agitating the wash load.  
   
   
       4 . The method of  claim 1 , further comprising presetting the signature fill rate.  
   
   
       5 . The method of  claim 1 , further comprising modifying the signature fill rate by determining a fill rate during an initial portion of the water fill stage.  
   
   
       6 . The method of  claim 5 , wherein determining the fill rate during the initial portion of the water fill stage comprises: 
 counting the water fill time during the initial portion of the water fill stage; and    measuring the water level during the initial portion of the water fill stage.    
   
   
       7 . The method of  claim 1 , further comprising calibrating the washing machine by modifying and storing the signature fill rate.  
   
   
       8 . The method of  claim 4 , further comprising calibrating the washing machine by modifying and storing the signature fill rate.  
   
   
       9 . An automatic washing machine comprising: 
 a tub for receiving a load of clothes;    a water level sensor operable to take water level measurements during a water fill stage; and    a controller controlling a water valve that introduces water into the washing machine, the controller comprising a timer, a memory and a microprocessor, wherein the microprocessor accesses a signature fill rate of the washing machine when unloaded, receives the water level measurements from the sensor during the water fill stage, the microprocessor being programmed to determine a measured fill rate, compare the measured fill rate to the signature fill rate and shut off the water valve when the measured fill rate is substantially equal to the signature fill rate.    
   
   
       10 . The washing machine of  claim 9 , wherein the water level sensor is a continuously variable pressure sensor.  
   
   
       11 . The washing machine of  claim 9 , wherein the water level sensor is a proximity sensor.  
   
   
       12 . The washing machine of  claim 9 , wherein the water level sensor is a radio frequency sensor.  
   
   
       13 . A method for controlling a water fill level of a washing machine, the method comprising: 
 measuring a fill rate of the washing machine during a water fill stage, the machine containing a wash load in an inner tub;    comparing the measured fill rate to a signature fill rate of the washing machine when unloaded; and    terminating the water fill stage when the measured fill rate is equal to the signature fill rate.    
   
   
       14 . The method of  claim 13 , further comprising agitating the wash load.  
   
   
       15 . The method of  claim 13 , further comprising: 
 calibrating the washing machine before water reaches the wash load in the inner tub; and    modifying the signature fill rate by determining a fill rate during an initial portion of the water fill stage.    
   
   
       16 . The method of  claim 15 , wherein determining the fill rate during the initial portion of the water fill stage comprises: 
 counting the water fill time during the initial portion of the water fill stage; and    measuring the water level during the initial portion of the water fill stage.    
   
   
       17 . The method of  claim 15 , further comprising presetting the signature fill rate in the machine.  
   
   
       18 . A method for controlling a water fill level of a washing machine having a wash load, the method comprising: 
 turning on a water valve to start a water fill stage;    monitoring a water fill rate during the water fill stage;    measuring fluctuations in the water fill rate;    determining a steady state fill rate; and    turning off the water valve.    
   
   
       19 . The method of  claim 18 , wherein determining a steady state fill rate comprises measuring substantial ceasing of fill rate fluctuations.  
   
   
       20 . The method of  claim 18 , wherein determining a steady state fill rate further comprises: 
 comparing the monitored water fill rate to a predetermined fill rate; and    determining that the monitored water fill rate is substantially equal to the predetermined fill rate.