US Patent 6935833 Recirculation structure for turbo chargers

Recirculation structure for turbocompressors, having a ring chamber which is arranged in the area of the free blade ends of a blade ring largely upstream of the latter and adjoins the main flow duct. A plurality of guiding elements are arranged in the ring chamber distributed over its circumference and are arranged and shaped in a fluidically advantageous manner with respect to the recirculation flow, with recesses provided in the leading and/or trailing area of the ring chamber. The side of the ring chamber which adjoins the contour of the main flow duct is open along its axial length as well as along its entire circumference, the free edges of the guiding elements being situated on the or close to the contour of the main flow duct.