Arrangement for automatic running gap control on a two or multi-stage turbine

Abstract

On a two or multi-stage turbine, expansion rings are provided in all stages at the sides of the rotors for passive, continuous running gap control whose thermal expansion and contraction behavior corresponds to that of the rotors and which are connected to radially moveable upstream and downstream stator vanes ( 5, 7 ). The downstream stator vanes are assembled to the upstream stator vanes via a bridge ( 16; 17, 18 ) which is axially and circumferentially fixed and located flexibly in the radial direction on the outer casing ( 10 ) of the turbine. The stator vanes ( 6 ) arranged between the rotor disks are integrally connected to the bridge or, as separate components, held axially and circumferentially on the bridge to take up rolling and tilting moments.

1 . An arrangement for automatic running gap control on a turbine having at least two stages, comprising
 first and second rotors within an outer casing,   shroud segments moveably arranged around the rotors,   stator vanes positioned upstream, between and downstream of these rotors,   an expansion ring associated to each of the rotors which is connected to radially moveable, upstream stator vanes and to radially moveable, downstream stator vanes and whose thermal expansion behaviour compares with that of the rotors,   a bridge connecting the upstream and downstream stator vanes at outer platforms thereof, the bridge being axially and circumferentially fixed and radially located on the outer casing, the intermediate stator vanes and shroud segments being attached to the bridge.   
   
   
       2 . An arrangement in accordance with  claim 1 , wherein the bridge includes a first half bridge and a second half bridge which is axially, radially and circumferentially held on the first half bridge, with the intermediate second stator vanes being integrally connected to the second half bridge. 
   
   
       3 . An arrangement in accordance with  claim 2 , wherein the first half bridge comprises a multitude of bending-resistant, circumferentially arranged supporting elements, with a circumferential gap provided between each of them, and a stiff attaching ring attached to the outer casing of the turbine to which the supporting elements are connected via radially flexible links, with a radial gap provided between the free ends of the ring and the supporting elements. 
   
   
       4 . An arrangement in accordance with  claim 2 , wherein the first half bridge and the second half bridge include a plurality of circumferentially arranged half-bridge elements, and each of the first half-bridge elements is located slideably in the radial direction by a guiding sleeve and a guiding pin which slideably engages the guiding sleeve, one of the guiding pin and the guiding sleeve attached to the half-bridge element and the other of the guiding pin and the guiding sleeve attached to and extending from the outer casing. 
   
   
       5 . An arrangement in accordance with  claim 1 , wherein the bridge includes a plurality of circumferentially arranged full-bridge elements which locate, at free ends thereof, in the outer platforms of the upstream and the downstream stator vanes. 
   
   
       6 . An arrangement in accordance with  claim 5 , wherein the intermediate stator vanes are integrally connected to the full-bridge elements. 
   
   
       7 . An arrangement in accordance with  claim 5 , wherein the intermediate stator vanes are separate components axially, radially and circumferentially fixed to the full-bridge elements. 
   
   
       8 . An arrangement in accordance with  claim 6 , wherein each of the full-bridge elements includes a radially slideable connection to the outer casing comprising a guiding sleeve and a guiding pin slideably engaging the guiding sleeve, one of the guiding pin and the guiding sleeve attached to the full-bridge element and the other of the guiding pin and the guiding sleeve attached to the outer casing, each of the intermediate stator vanes including a locating web which engages a circumferential groove of a retaining ring. 
   
   
       9 . (canceled) 
   
   
       10 . (canceled) 
   
   
       11 . (canceled) 
   
   
       12 . (canceled) 
   
   
       13 . An arrangement in accordance with  claim 1 , comprising seals positioned between the outer platform of the downstream stator vanes and the outer casing. 
   
   
       14 . An arrangement in accordance with  claim 3 , comprising a split ring fixing ring for axial fixation between the supporting elements and the half-bridge elements. 
   
   
       15 . An arrangement in accordance with  claim 3 , wherein the supporting elements and the half-bridge elements are stiffened by reinforcing elements. 
   
   
       16 . An arrangement in accordance with  claim 5 , comprising seals positioned between the full-bridge element and the outer casing. 
   
   
       17 . An arrangement in accordance with  claim 5 , comprising a split ring fixing ring for axial fixation between the full-bridge elements and the separate intermediate stator vanes. 
   
   
       18 . An arrangement in accordance with  claim 5 , wherein the full-bridge elements are stiffened by reinforcing elements.