STEAM TURBINE MEAN PRESSURE CYLINDER

FIELD: power engineering. SUBSTANCE: invention can be used at designing and modification of mean pressure cylinders of steam turbines operating with steam reheating and turbines for nuclear power stations. Proposed mean pressure cylinder of steam turbine has housing with steam intake chamber, first stage guide vane assembly, first stage blades with periphery shroud installed with clearance after guide valve assembly, stator shell installed radially over shroud of first stage blades installed on stator at side of second stage diaphragm so that ring space is formed between shell and housing, and axial clearance is formed between shell and end face of guide vane assembly. Axial clearance between trailing edges of guide vanes and loading edges of first stage blades is made within z* = z/(t1sinalpha1) = 1,5-2,5 where z is distance from trailing edges of guide vanes to leading edges of blades along turbine axis; t1 is guide vane pitch; alpha1 is angle of getting out of steam flow from guide vane assembly. Ring space is connected through separator with lower pressure space. EFFECT: improved reliability and economy of first stages of mean pressure cylinder owing to reduction of abrasive wear of blades and overshroud seals. 4 cl, 3 dwg