Axial turbine with annular valve for steam tapping control - has servo assisted positioner in fixed axial location linked to valve to allow different axial valve locations

摘要

The positioning system for controlling the tapping of steam in an axial flow turbine has an annular valve unit (2) in the housing (1) and a servo positioner (4) outside the housing which operates the valve via an actuator rod (5) extending through the housing wall in a direction tangential to valve. To enable the use of standard housings for different axial locations of the valve in different turbines, the positioner has a fixed axial location whilst the valve can be arranged in different axial locations depending on the pressure of the steam to be tapped. The tod (5) may be connected with a flat bar (6) having its broad side facing the valve, which bar is, in turn connected to the valve by flat arms (8) having their broad sides facing in axial direction, to accommodate relative radial movement and axial displacement by resilience of bar and arms.