Patent ID: 9650911
Date: 2017-05-16
CPC Classifications: F01D,F02B,F05D,Y02T

Claim:
1. A variable geometry turbine comprising: a turbine wheel supported in a housing for rotation about a turbine axis, the turbine wheel being a radial-inflow axial-outflow turbine wheel and the housing having a first wall; an axially movable operating member having a second wall; a primary inlet passage upstream of the turbine wheel, the inlet passage being defined between the first wall of the housing and the second wall of the operating member, the axial width of the inlet passage being controllable by moving the operating member between a first axial position in which the second wall is axially distal from the first wall, and a second axial position in which the second wall is axially proximal to the first wall; a secondary inlet passage configured to provide a bypass flow path for a working fluid which circumnavigates at least part of the primary inlet passage; a seal element and one or more apertures, one of the seal element and the one or more apertures being axially fixed relative to the housing and the other being axially fixed relative to the operating member and movable therewith, the one or more apertures and the seal element thereby being axially movable relative to one another between a first configuration and a second configuration via movement of the operating member, wherein: with the one or more apertures and the seal element in the first configuration the seal element is positioned in the bypass flow path to substantially prevent fluid flow therethrough, and with the one or more apertures and the seal element in the second configuration the seal element is positioned to allow flow of fluid through the one or more apertures and thereby through the secondary inlet passage; the seal element and the one or more apertures are arranged whereby moving the operating member to the first position positions the seal element and the one or more apertures in the first configuration, and moving the operating member to the second position positions the one or more apertures and the seal element in the second configuration; the secondary inlet passage has an outlet configured to direct working fluid to exit the secondary inlet passage in a direction which has an axial component in the opposite direction to a direction of axial outflow of the turbine wheel: and the secondary inlet passage is annular in shape and is circumferentially arranged about the turbine axis.