| CPC A47L 9/248 (2013.01) [A47L 9/0081 (2013.01)] | 45 Claims |

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1. A cleaning apparatus, comprising at least one noise source and an air guidance device having at least one flow deflection element, wherein the at least one flow deflection element has a first duct arm and a second duct arm, wherein the second duct arm is oriented transversely to the first duct arm, and wherein the first duct arm and the second duct arm have a common edge at an external corner region, wherein arranged in an interior of the at least one flow deflection element is a built-in wall which covers the edge in the interior, wherein the built-in wall faces a through-flow region in the interior, and wherein the built-in wall takes a form such that it guides flow and is sound-permeable,
wherein a region of transition from the first duct arm to the second duct arm has, at an internal corner region which lies opposite the external corner region, a wall that is curved relative to the interior of the at least one flow detection element, and
wherein a circle of curvature for the curved wall has an internal radius that is greater than half of a hydraulic diameter of a first opening of the first duct arm.
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