Governor control linkage assembly for overspeed protection of turbines during restarting

摘要

A governor control linkage assembly to be connected between the governor and a valve to be controlled by the governor such as the inlet valve for a steam turbine upstream from a venturi type safety trip valve therein in one preferred form with Woodward T.G.-10 governors has a main lever arm connected at one end to the governor for actuation thereof and to the opposite end to a pivot arm on a fulcrum assembly which permits the pivot arm to be moved by a manually operable threaded assembly connected thereto so as to move the inlet valve from open to closed position and from closed to open position when the turbine is shut down to aid in the restarting thereof. In another preferred form with Woodward P.G. governors the governor control linkage assembly consists of an articulated lever wherein a main lever arm and a pivot arm are connected so that the main lever and pivot arm can be moved relative to each other by an interconnecting manually operable threaded assembly to move the associated inlet valve from open to closed position and from closed to open position. The control linkage assemblies for the respective types of governors being operable essentially as shut-off devices to facilitate resetting of the associated safety trip valve with full line pressure at the steam chest and to be used as a manual control for restarting the turbine from the stopped position.