An exemplary axial flow steam turbine is disclosed which includes a motor, a turbine casing and at least first and second turbine stages, with the second turbine stage being located adjacent to and downstream from the first turbine stage. A radially outer static diaphragm ring of the second turbine stage includes an annular axial extension extending in an upstream axial direction and carrying a circumferential tip sealing device which cooperates with shrouds of a circumferential row of moving blades of the first turbine stage. An upstream end of the annular axial extension is axially spaced from a radially outer static diaphragm ring of the first turbine stage such that a circumferential passage is defined between the upstream end of the annular axial extension and the radially outer static diaphragm ring of the first turbine stage. Solid particles are diverted from steam flow by a circumferential passage during operation.