Patent ID: 7650766
Filing Date: 2010-01-26
Classification: D06F

Abstract:
1. A washing machine comprising: a tub; a resistance network comprising a sensor, a resistor, and a voltage source, said sensor positioned and configured to sense a conductivity of a fluid in said tub, said voltage source operable to provide one of a sinusoidal wave input and a square wave input to said sensor to facilitate deterring mineral buildup on said sensor; and a controller operatively coupled to said sensor and configured to control an amount of the fluid in said tub during a rinse cycle based on the conductivity of the fluid measured at an end of a wash cycle, said controller comprising a microcomputer coupled to a memory storing instructions that, when executed by the microcomputer, directs said controller to: determine a desirable achievable rinse level; at predetermined fluid levels during the rinse cycle, measure an average liquid conductivity; calculate an overall change in conductivity based on the measured average liquid conductivity at each predetermined fluid level; compare the calculated overall change in conductivity to the desirable achievable rinse level; and cease the rinse cycle when the overall change in conductivity exceeds an acceptable change percentage of the desirable achievable rinse level.