US Patent 7635003 Dishwasher and controlling method thereof

A dishwasher is provided. The dishwasher includes a sump, a wash motor, a disposer, a screen filter, and a drain motor. The sump stores wash liquid. The wash motor pumps the wash liquid stored in the sump. The disposer is installed inside the sump and connected to the wash motor by a motor shaft. The screen filter is installed inside the sump to prevent impurities ground by a rotation of the disposer from entering a wash pump. The drain motor discharges the wash liquid stored in the sump to an outside. The wash motor operates for a predetermined duration during a draining process performed by an operation of the drain motor.