Shaft seal for steam turbines

Abstract

A shaft seal for steam turbines is provided. The shaft seal steam barrier is supplied with a slight excess pressure. In order to avoid complex additional devices necessary for liquefying the water vapor once again, a condensation chamber, which is sealed from the surrounding air as well as from the steam barrier chamber with brush seals, is provided between the steam barrier chamber and the surrounding air. The condensation chamber is constructed in such a manner that the heat, developing in the interior thereof, is discharged to the outside.

1 .- 3 . (canceled) 
   
   
       4 . A shaft seal for steam turbines, comprising:
 a shaft-seal sealing chamber;   a condensation chamber provided between the sealing-steam chamber and a surrounding air;   a plurality of brush seals,   wherein the shaft-seal sealing chamber is fed with a slight overpressure,   wherein the condensation chamber is sealed by the plurality of brush seals both in relation to the surrounding air and in relation to the sealing-steam chamber, and   wherein the condensation chamber is constructed so that the heat which develops therein is discharged to the outside.   
   
   
       5 . The shaft seal as claimed in  claim 4 , wherein the condensation chamber is fixed with a flange and wherein an insulating layer is arranged between the condensation chamber and steam turbine. 
   
   
       6 . The shaft seal as claimed in  claim 4 , wherein the condensation chamber is cast onto the steam turbine and is insulated in relation to the steam turbine. 
   
   
       7 . The shaft seal as claimed in  claim 4 , wherein the sealing-steam chamber is sealed in relation to an inside of the steam turbine by a labyrinth seal.