Patent ID: 8568084
Filing Date: 2013-10-29
Classification: F01D,F05D

Abstract:
1. A system for controlling a net thrust of a steam turbine having a rotating shaft, the system comprising: an active-retractable seal (ARS) for sealing against the rotating shaft adjacent to a stepped portion on the rotating shaft in a turbine section; a first leak off line fluidly coupling a first stage of the turbine section to a packing area adjacent to the ARS, the first leak off line including a first control valve and a second control valve; a second leak off line fluidly coupling a second stage of the turbine section having a pressure different than the first stage to a step area immediately adjacent to the stepped portion, the second leak off line including a third control valve; a connection line fluidly coupling the first leak off line to the second leak off line, wherein the connection line is coupled to the second leak off line after the third control valve and is coupled to the first leak off line between the first control valve and the second control valve, and wherein the connection line includes a fourth control valve; and a controller configured to actively control the control valves to control the net thrust by regulating thrust pressure on the stepped portion.