Patent ID: 8714915

Claim:
An axial flow steam turbine comprising: a turbine casing containing a turbine stage, the turbine stage comprising: a row of static blades; a row of moving blades located downstream of the static blades in a turbine passage, the moving blades having radially outer shrouds that sealingly co-operate with an outer wall portion of the turbine passage; and a circumferentially and radially extending passage provided in the outer wall portion upstream of the row of moving blades to divert solid particles from steam flow during operation of the steam turbine, wherein the turbine casing between adjacent turbine stages includes a circumferential collection channel for collecting solid particles diverted through the circumferentially and radially extending passage, wherein the circumferential collection channel includes plural circumferentially spaced flow arresters arranged to minimise circumferential flow of solid particles within the circumferential collection channel, and wherein each of the circumferentially spaced flow arresters extends axially across the circumferential collection channel to divide the circumferential collection channel into plural circumferential compartments.