Two stage reaction type steam turbine - has separate steam inlet headers with separately controlled flows to give even loading

摘要

The turbine has a rotor (1) carrying two sets of reaction blading (8, 9). Flow is from the centre outwards and the inlet header spaces (4, 5) in the stator are separated by a central partition (3) which has a labyrinth seal (6) to the shaft. Steam is admitted to these two headers from a common header (10) surrounding them and the flow from the common header to the individual headers is controlled by separate valves (11, 12) for each individual header. Turbine output is controlled by varying the flow through these valves. The interposition of the individual headers between the main header and the blades ensures that a reduced steam flow is evenly distributed over all blades. This eliminates uneven loading and so reduces the stresses in the blades.