Assembly for controlling the flow of cooling air in an engine turbine

A blade root sockets provided in the discs of a turbine rotor have passages for cooling air which are arranged to be variably blocked by closure means carried by the upstream and downstream ends of the labyrinth carriers disposed between the discs. The labyrinth carriers are of the pin-like type and are able to expand and contract in response to the temperature of the gas flow passing through the turbine, moving the closure means to open or close the passages. The positions of the closure means adjacent the passages are determined by the relative dimensions and the thermal expansion coefficients of the discs and the labyrinth carriers, and may be chosen to provide full cooling air flow during engine acceleration, a reduced flow during stable operation, and a very restricted flow to the first disc only during deceleration.