DOUBLE-FLOW CYLINDER OF MEDIUM PRESSURE IN STEAM TURBINE Russian patent published in 2017 - IPC F01D3/02 F01D5/08 F01D25/12 

FIELD: machine engineering.

SUBSTANCE: double-flow medium pressure cylinder of a steam turbine is proposed which includes an outer and inner bodies, a rotor with discs and working blades of the flow part of forward and reverse flow, the guide blades of the first stages of the forward and reverse flows, the diaphragms of the second stages of the forward and reverse flows, an annular shielding body installed in the central part of the inner body, and a cage located axially symmetrically inside the shielding body and provided with annular chambers connected to each other and provided with holes on inner and end cage walls, the cooling steam supply pipeline from external source to the cage, at that annular chambers and nozzles are installed in the diaphragms of the second stages of the forward and reverse flows, there are openings provided in the guide blades of the diaphragms of the second stages with both flows, and the annular chambers in the diaphragms are connected by means of pipelines to external source with cooling vapor, in addition, steam bypass holes are provided in the annular shielding body, and the cooling steam supply line from the external source to the cage is installed in additional protective pipeline, fixed in the inner body.

EFFECT: improving the reliability of the turbine cylinder by increasing the cooling efficiency of the first stage and central rotor portion, the design of the cooling system, with the pressure differences behind the guide blades of the first stages between the forward and reverse flows up to 100 KPa, providing reliable cooling of the central rotor part of the double-flow cylinders and the most stressed disxs of the first stages of both flows from the steam inlet side and from the side of the second stages, the creep of the metal decreases, its long-term strength increases, in a result, the service life of the rotor is prolonged, installation of additional pipeline also significantly improves rotor cooling efficiency due to shielding effect obtained when installing the cooling vapor supply line in the additional protective pipeline.

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