Dishwasher

Abstract

The present invention relates to a dishwasher which can sense the turbidity of washing water in real time regardless of specific measurement conditions, and thus can effectively identify the progress of an operation, and which can identify the progress of the operation in real time through a turbidity sensor.

1 . A dishwasher comprising:
 a tub defining a washing space therein;   a sump disposed under the tub and constructed to store washing water to be supplied to the tub therein;   a washing water pump configured to pressurize the washing water and supply the pressurized washing water to the washing space;   a turbidity sensor configured to sense turbidity values of the washing water; and   a controller electrically connected to the turbidity sensor and the washing water pump, wherein the controller is configured to detect the turbidity values of the washing water via the turbidity sensor during a cycle and determine whether to continue the cycle based on the detected turbidity values.   
     
     
         2 . The dishwasher of  claim 1 , wherein the controller configured to determine whether to continue the cycle is further configured to calculate a rate of change of turbidity values during a washing cycle and determine whether to continue the washing cycle based on the calculated rate of change. 
     
     
         3 . The dishwasher of  claim 2 , wherein the controller configured to determine whether to continue the washing cycle is further configured to:
 receive an output signal from the turbidity sensor and detect turbidity values of the washing water after operation of the washing water pump is initiated;   sample the detected turbidity values of the washing water at a first interval and store the sampled turbidity values;   calculate an average value of the turbidity values sampled for a first time period and stored to calculate a first turbidity average value;   sample turbidity values of the washing water detected after calculating the first turbidity average value at a second interval and store the sampled turbidity values;   calculate an average value of the turbidity values sampled for a second time period after calculating the first turbidity average value to calculate a second turbidity average value; and   calculate a rate of change of the second turbidity average value compared to the first turbidity average value and determine whether the calculated rate of change exceeds a reference rate of change.   
     
     
         4 . The dishwasher of  claim 3 , wherein the controller is further configured to determine to stop the washing cycle when the calculated rate of change is determined to be smaller than or equal to the reference rate of change. 
     
     
         5 . The dishwasher of  claim 4 , wherein the controller is further configured to stop the operation of the washing water pump when the stopping of the washing cycle is determined. 
     
     
         6 . The dishwasher of  claim 3 , wherein the first interval and the second interval are equal to each other. 
     
     
         7 . The dishwasher of  claim 6 , wherein the first interval and the second interval are 1 second. 
     
     
         8 . The dishwasher of  claim 3 , wherein the first time period and the second time period are equal to each other. 
     
     
         9 . The dishwasher of  claim 3 , wherein the reference rate of change is 10%. 
     
     
         10 . The dishwasher of  claim 1 , wherein the controller configured to determine whether to continue the cycle is further configured to determine whether to continue a rinsing cycle based on turbidity values measured during the rinsing cycle. 
     
     
         11 . The dishwasher of  claim 10 , wherein the controller configured to determine whether to continue the rinsing cycle is further configured to:
 receive an output signal from the turbidity sensor and detect turbidity values of the washing water;   sample the detected turbidity values of the washing water at a third interval and store the sampled turbidity values; and   determine whether the sampled turbidity values exceed a reference turbidity value.   
     
     
         12 . The dishwasher of  claim 11 , wherein the controller is further configured to determine to stop the rinsing cycle when the sampled turbidity values are determined to be smaller than the reference turbidity value. 
     
     
         13 . The dishwasher of  claim 12 , wherein the controller is further configured to stop operation of the washing water pump when the stopping of the rinsing cycle is determined. 
     
     
         14 . The dishwasher of  claim 11 , wherein the third interval is 1 second. 
     
     
         15 . The dishwasher of  claim 11 , wherein the reference turbidity value is 100 NTU.