Performance characteristics stabilization in a radial compressor

Arrangement for performance characteristics stabilization in a radial compressor comprising a housing with an inlet area, an outlet area and an impeller disposed between the inlet and outlet areas and capable of transporting, upon rotation, a medium from the inlet area to the outlet area, said impeller having a contour which changes in axial direction from a diameter at its inlet to a diameter at its outlet in accordance with the profile of a contour wall of the surrounding housing, said arrangement for performance characteristics stabilization comprising a contour ring disposed adjacent the impeller and defining an inlet passage for guiding a main medium flow from said inlet area to said impeller, a venting space surrounding said contour ring and extending from said inlet area to said contour wall, said venting space being in communication with said inlet passage at said inlet area via an inlet communication opening and at the impeller inlet via a stabilization opening disposed intermediate the impeller inlet and the impeller outlet, and an inlet ring exchangeably mounted in said inlet area adjacent said venting space and having a conical inlet end for constricting said main medium flow to said contour ring ahead of said impeller, said inlet ring having an inner radial end wall limiting said venting space and defining said venting space inlet communication opening for controlling medium conditions in said venting space.