US Patent 11672395 Surface cleaning apparatus

A surface cleaning apparatus having an air flow path; a suction motor positioned in the air flow path; an air treatment chamber provided in the air flow path; and a porous filter provided in the air treatment chamber and including an outlet passage from the air treatment chamber. An air impermeable impact wall in the air treatment chamber is opposed to an inlet into the air treatment chamber. At least a portion of the impact wall or a deflecting portion of a wall defining part of the front end of the air treatment chamber imparts a circular flow to air entering the air treatment chamber.