Spring system designs for active and passive retractable seals

摘要

A spring assembly for a retractable turbine rotor seal supported in an arcuate segment may include in one embodiment a first radially inner restraining plate having a lower surface adapted to engage a surface of a turbine stator, and a flat upper surface provide with an upstanding hub; a second radially outer restraining plate having a flat lower surface and an upper surface adapted to engage a surface of the arcuate segment, the radially outer restraining plate formed with an opening receiving the upstanding hub; and at least one spring telescoped over the upstanding hub and exerting a radially outward biasing force on the second radially outer restraining plate, and adapted to exert a radially outward retracting force on the arcuate segment.