Steam turbine comprising a thrust balance piston

Abstract

A cooling mechanism for a steam turbine is provided, which has, in the area of the valve connection a cooling channel, into which cooling steam flows from the flow channel, the steam then being fed as cooling steam in the area of the thrust balance piston.

1 . A steam turbine having an outer housing and an inner housing, comprising:
 a rotor, comprising a plurality of rotor blades, which has a thrust compensating piston being arranged in a rotationally mounted manner within the inner housing,   the inner housing having an inner housing end region which is formed around the thrust compensating piston,   a seal which seals a third pressure space which is arranged between the inner housing end region and the outer housing, the inner housing having a feed channel which connects a first pressure space to a thrust compensating piston pre-space which is arranged between the thrust compensating piston and the inner housing, the first pressure space being arranged between the inner housing and the outer housing,   wherein the steam turbine has a connection which connects the third pressure space in terms of flow to the thrust compensating piston pre-space, a further seal being provided which is arranged between the inner housing and the outer housing, the third pressure space being arranged between the seal and the further seal.   
     
     
         2 . The steam turbine as claimed in  claim 1 , the seal being configured as a piston ring. 
     
     
         3 . The steam turbine as claimed in  claim 1 , the connection opening into the feed channel. 
     
     
         4 . The steam turbine as claimed in  claim 1 , further comprising:
 a flow channel having a plurality of blade stages being formed between the inner housing and the rotor,   the inner housing having an outward channel which is formed as a communicating line between the flow channel downstream of a blade stage and the first pressure space.   
     
     
         5 . The steam turbine as claimed in  claim 1 , further comprising:
 a valve for feeding steam into the flow channel, and   an annular cooling channel being formed in the valve, which wherein the annular cooling channel is connected in terms of flow to the first pressure space.   
     
     
         6 . The steam turbine as claimed in  claim 5 , wherein the annular cooling channel is connected in terms of flow to the third pressure space. 
     
     
         7 . The steam turbine as claimed in  claim 5 , wherein the valve comprising comprises a valve diffuser, and the annular cooling channel is arranged between the valve diffuser and the outer housing. 
     
     
         8 . The steam turbine as claimed in  claim 5 , comprising a further cooling channel being arranged in the outer housing as a space connection to the third pressure space.