ANORDNING FOER ATT REGLERA EN AVTAPPNINGSTURBINS AVTAPPNINGSTRYCK

This invention relates to a device for controlling the extraction pressure of an extraction condensing turbine with pivotable vanes or vane parts of guide vane lattices arranged downstream of the steam extraction point(s) where the pivoting motion of the vanes is effected by means of adjusting levers or arms by axial displacement of adjusting rings forming the bearings said adjusting levers or arms. According to the invention, the adjusting rings (15) are solidly connected to annular pistons (11, 12) which are axially slidably supported in the annular space (6) of an annular casing (7, 9, 10) arranged coaxially to and surrounding the rotor shaft (4) on one or a plurality of coaxial rods (13) or similar guiding means and which are provided with seal strips (14) on their radially outer and radially inner peripheral surfaces; furthermore, the pressure spaces (23a, 23b) of the two annular pistons (11, 12) are supplyable via pipes (21, 22) with the turbine's own steam at a correspondingly high pressure whereas the suction space or, respectively, each suction space communicates through corresponding passages (24, 5, 29) with the low-pressure spaces downstream of the guide vanes (18).