Shape memory alloy intersegment seals

Abstract

A high-temperature seal for use in sealing gaps between adjacent turbine components includes a seal body constructed of a shape-memory alloy having inoperative size and shape that, in use, expands to an operative size and shape where it is in sealing engagement with the adjacent turbine component upon reaching a predetermined transition temperature. Upon subsequent cooling to a temperature below the predetermined temperature, the seal body reverts to the first inoperative shape or to another inoperative size and shape.

1 . A high-temperature seal for use in sealing gaps between adjacent turbine components comprising:
 a seal body constructed of a shape-memory alloy having a first inoperative size and shape that, in use, expands to a predetermined operative size and shape where it is in sealing engagement with the adjacent turbine component upon reaching a predetermined transition temperature, and upon subsequent cooling to a temperature below the predetermined temperature, reverts to a second inoperative size and shape different than said first inoperative size and shape.   
     
     
         2 . The high-temperature seal of  claim 1  wherein said seal body is provided with a planar center portion constructed of a substantially rigid alloy material and a pair of end portions constructed of an alloy with shape-memory characteristics. 
     
     
         3 . The high-temperature seal of  claim 2  wherein said center portion is comprised of shape-memory alloy material but is rigidified by a separate seal component attached to said center portion. 
     
     
         4 . The high-temperature seal of  claim 2  wherein said end portions each comprise a single curl. 
     
     
         5 . The high-temperature seal of  claim 2  wherein said end portions each comprise a double curl. 
     
     
         6 . The high-temperature seal of  claim 2  wherein at least said planar center portion is wrapped with a cloth seal material. 
     
     
         7 . The high-temperature seal of  claim 1  wherein said predetermined transition temperature lies in a range of from 600° F. to 2400° F. 
     
     
         8 . The high-temperature seal of  claim 1  wherein said seal body is rectangular in its first inoperative shape 
     
     
         9 . The high-temperature seal of  claim 1  wherein said seal body is substantially rectangular in its second inoperative shape but larger in size that in its first inoperative shape. 
     
     
         10 . A high-temperature seal for use in sealing gaps between adjacent turbine components comprising a seal body including substantially planar center portion and a pair of profiled end portions, at least said profiled portions formed of a shape-memory alloy material designed to expand upon exposure to temperatures in a range of from about 600° F. to about 2400° F. to an operative shape, thereby causing said profiled portions to engage surfaces of said adjacent turbine components; and wherein said profiled end portions are designed to revert to an inoperative shape when the temperatures drop below said range. 
     
     
         11 . The high-temperature seal of  claim 10  wherein said substantially planar center portion comprises a substantially rigid alloy material with or without shape-memory characteristics. 
     
     
         12 . The shape-memory alloy seal of  claim 10  wherein said profiled end portions each comprise a single curl. 
     
     
         13 . The shape-memory alloy seal of  claim 10  wherein said profiled end portions each comprise a double curl. 
     
     
         14 . The shape-memory alloy seal of  claim 10  wherein said substantially planar center portion is wrapped with a cloth seal material. 
     
     
         15 . A high-temperature seal for use in sealing gaps between surfaces of adjacent turbine components comprising:
 a seal body including substantially planar center portion and a pair of profiled end portions each profiled end portion comprising at least one curl; at least said pair of profiled end portions formed of a shape-memory alloy material designed to change shape upon heating to temperatures higher than a predetermined transition temperature from a first inoperative shape to an operative shape, thereby causing said profiled end portions to expand and establish a seal between said surfaces of said adjacent turbine components; and wherein said center portion is rigidified by a separate seal component and covered with a cloth seal fabric.   
     
     
         16 . The high-temperature seal of  claim 15  wherein said separate seal component and said cloth seal fabric cover both sides of said substantially planar center portion. 
     
     
         17 . The high-temperature seal of  claim 15  wherein at least said profiled end portions exhibit one-way shape-change characteristics. 
     
     
         18 . The high-temperature seal of  claim 15  wherein said exhibit two-way shape-change characteristics. 
     
     
         19 . The high-temperature seal of  claim 18  wherein said profiled end portions revert to said inoperative shape at temperatures below said transition temperatures. 
     
     
         20 . The high-temperature seal of  claim 18  wherein said profiled end portions revert to a second inoperative shape other than said first inoperative shape at temperatures below said transition temperature.