Self-adjusting device for controlling the clearance between rotating and stationary components of a thermally loaded turbo machine
View Patent ↗A self-adjusting device for controlling the clearance (C), especially in the radial direction, between rotating and stationary components of a thermally loaded turbo machine, changes clearance (C) in a linear and/or non-linear way during transition of the machine between standstill and steady-state operation. Simple and effective control can be achieved, even in the case of a nonlinear variation of the clearance during transitional operation, by the self-adjusting device including at least two different driving elements (A, B) to move the rotating and fixed components relative to each other in order to change the clearance (C) between them, and by the different driving elements (A, B) being configured to be activated at different times during the transition of the machine.
1. A self-adjusting device for controlling a clearance between rotating and stationary components of a thermally loaded turbo machine, said rotating and stationary components include rotating blades, stationary vanes, or both, said rotating blades and/or stationary vanes including respective blade or vane tips and associated heat shields arranged opposite to the respective blade or vane tips, and wherein the self-adjusting device is drivingly connected to at least one of said associated heat shields, and which clearance changes in a non-linear way in a time-span during transition of the turbo machine between standstill and steady-state operation or during transition of the turbo machine between steady-state and standstill operation, the self-adjusting device comprising:
at least two different driving elements configured and arranged to move the rotating and stationary components relative to each other and to change said clearance when positioned in said turbo machine, wherein the at least two different driving elements are configured and arranged to be automatically activated when a predefined activation temperature is reached and configured to be activated at different times within said time-span during said transition of the turbo machine, and wherein the at least two different driving elements have different activation temperatures and are arranged within the self-adjusting device such that the at least two different driving elements experience a same temperature or nearly same temperature condition within the self-adjusting device during the transition of the turbo machine, and wherein the at least two different driving elements have at least a first activation temperature and a second activation temperature during transition of the turbo machine from standstill to steady-state operation, the first activation temperature configured to move the at least one of said associated heat shields movably mounted in a support of the stationary component away from said respective blade or vane tips of the rotating component and the second activation temperature configured to move the at least one of said associated heat shields toward the respective blade or vane tips of the rotary component, and wherein the second activation temperature is greater than the first activation temperature, wherein the support includes a first, movable support with an axial guidance, a second, stationary support for the first, movable support, and a third support;
return springs; and
wherein the at least two different driving elements and the return springs generate planar movement by the at least two different driving elements, which are arranged within a certain angle to each other.
2. The self-adjusting device according to claim 1 , wherein the at least two different driving elements are arranged at a 90 degree angle to each other.