Patent ID: 7350527

Claim:
A filter system for a dishwasher having a floor, a wash pump and a drain pump, the filter system comprising: a sump in the floor having a sidewall and a bottom wall having an inlet leading to the wash pump and an inlet leading to the drain pump; a filter assembly positioned in the sump including: a generally vertical filter retainer and an overlying perforate hood; a multiple porosity filter element carried on the filter retainer; and a back wash sprayer connected to the wash pump and rotatably mounted inside the filter retainer and having at least one nozzle directed toward the filter element; and a dishwasher control, and a pressure sensor positioned on the sidewall of the sump to detect accumulation of soil particles on the filter element and connected to the dishwasher control and arranged to activate the drain pump to remove soil particles from the sump when a predetermined accumulation of soil particles is detected, the sensor being arranged to detect that the back wash sprayer is rotating and the dishwasher control is arranged to provide a check filter signal to the user when the sensor fails to detect back wash sprayer rotation; wherein the inlet leading to the wash pump is positioned inside the filter assembly and the inlet leading to the drain pump is positioned outside the filter assembly.