US Patent 7147429 Turbine assembly and turbine shroud therefor

A turbine assembly includes a shroud for being mounted around a last stage of the low pressure turbine rotor. The shroud includes an arcuate body having spaced-apart forward and aft ends and spaced-apart circumferential ends. Attachments are provided for securing the shroud body to the surrounding engine case. An arcuate extension member protrudes rearward from the aft end of the shroud body. The extension member has an inner surface which defines a portion of the gas flowpath through the engine. Seals may be provided to prevent leakage between adjacent shroud segments. The shroud is especially useful for protecting a downstream turbine frame from debris and thermal stress.