Method and apparatus for clearance control of turbine blade tip

Abstract

A gas turbine including a casing and a shroud ring, the gas turbine including an attachment device rigidly attached to the casing and at least one of the shroud ring and a duct attached to the shroud ring, wherein the device allows the shroud ring to expand and contract independent of the casing and provides limited net axial growth of the shroud ring.

1 . A gas turbine comprising a casing and a shroud ring, the gas turbine comprising:
 an attachment device rigidly attached to the casing and at least one of the shroud ring and a duct attached to the shroud ring, wherein the device allows the shroud ring to expand and contract independent of the casing and provides limited net axial growth of the shroud ring.   
   
   
       2 . The gas turbine as in  claim 1 , wherein the net axial growth is about zero. 
   
   
       3 . The gas turbine as in  claim 1 , wherein the device comprises a spring. 
   
   
       4 . The gas turbine as in  claim 3 , wherein the spring comprises a general “C” shape. 
   
   
       5 . The gas turbine as in  claim 3 , wherein the spring comprises a general “W” shape. 
   
   
       6 . The gas turbine as in  claim 3 , wherein the spring comprises a rail for coupling to the casing. 
   
   
       7 . The gas turbine as in  claim 1 , wherein the device comprises a 360° segment. 
   
   
       8 . A gas turbine comprising a casing and a shroud ring, the gas turbine comprising:
 a plurality of springs shaped generally as a “C” rigidly attached to the casing and at least one of the shroud ring and a duct attached to the shroud ring, wherein the device allows the shroud ring to expand and contract independent of the casing and provides limited net axial growth of the shroud ring.   
   
   
       9 . A method for controlling a dimension of a shroud ring in a gas turbine comprising a casing, the method comprising:
 establishing the dimension for the shroud ring; and   controlling a size of the shroud ring to maintain the dimension using an attachment device rigidly attached to the casing and at least one of the shroud ring and a duct attached to the shroud ring, wherein the device allows the shroud ring to expand and contract independent of the casing and provides limited net axial growth of the shroud ring.   
   
   
       10 . The method as in  claim 9 , wherein the method is implemented by a computer program product stored on machine-readable media and comprising machine executable instructions for controlling a dimension of a shroud ring in a gas turbine comprising a casing, the product comprising instructions for:
 establishing the dimension for the shroud ring; and   controlling a size of the shroud ring to maintain the dimension using an attachment device rigidly attached to the casing and at least one of the shroud ring and a duct attached to the shroud ring, wherein the device allows the shroud ring to expand and contract independent of the casing and provides limited net axial growth of the shroud ring.