Abstract: An automatic dishwasher having a wash chamber is provided with a filter for filtering wash liquid circulated in the wash chamber. The filter includes a filter chamber outside the wash chamber. An inlet to and outlet from the filter chamber in a wall of the wash chamber allows wash liquid circulating in the wash chamber to enter the filter chamber and to flow out of the filter chamber through a filter element back into the wash chamber for filtering particulate material from wash liquid circulating in the wash chamber. A drain outlet at the bottom of the filter chamber allows wash liquid and material filtered by the filter to flow to the household drain. Sensors can be provided to detect a clogged or partially clogged filter and initiate a purge cycle to remove wash liquid and material filtered by the filter to the household drain.

Abstract: A filter system for dishwasher with a sump having inlets leading to a wash pump and a drain pump in the bottom wall. The filter assembly includes a vertical filter retainer an overlying perforate hood, a multiple porosity filter element carried on the filter retainer and a back wash sprayer rotatably mounted inside the filter retainer with at least one backwash nozzle directed toward the filter assembly. The inlet leading to the wash pump is positioned inside the filter element and the inlet to the drain pump is located outside the filter element. The filter element has openings that vary in size from the top to the bottom of the filter element. The filter element openings can be arranged in bands of different porosity openings including fine, medium and coarse porosity openings. The perforate hood can have coarse porosity openings.