Sealing arrangement

Abstract

A face seal acts across a gap between first and second machine, particularly a gas turbine, components operating at elevated temperatures. One end of a sealing element is housed in a recess in the first component and its other end seals against a plane surface of the second component under the action of a spring. To allow assembly of the components and the seal within, say, a gas turbine engine without damaging the seal or other components, the sealing element is temporarily retained entirely within the recess by a latch, the latch being temperature-sensitive and operative only once to release the sealing element to perform its sealing function at a predetermined elevated temperature. The latch may be a fusible pin.

1 . A sealing arrangement for acting across a gap between first and second machine components operating at elevated temperatures, comprising: 
 a) at least one sealing element having a first end captured within the first component and a second end able to seal against a surface of the second component;    b) spring means acting between the first component and the at least one sealing element to urge the at least one sealing element towards the second component; and    c) retention means for temporarily retaining the at least one sealing element within outer dimensions of the first component, the retention means being temperature-sensitive and operative only once to release the at least one sealing element to perform its sealing function at a predetermined elevated temperature.    
   
   
       2 . The sealing arrangement according to  claim 1 , in which the temperature-sensitive retention means is at least one fusible detent that at the predetermined elevated temperature fails by one of softening and melting of the material of which it is made, thereby releasing the at least one sealing element.  
   
   
       3 . The sealing arrangement according to  claim 1 , in which the fusible detent comprises a fusible latch that is held in the first component and that projects into the at least one sealing element.  
   
   
       4 . The sealing arrangement according to  claim 1 , in which the temperature-sensitive retention means is at least one detent that at the predetermined elevated temperature fails by one of embrittlement and charring of the material of which it is made, thereby releasing the at least one sealing element.  
   
   
       5 . The sealing arrangement according to  claim 2 , in which the fusible detent comprises a pin.  
   
   
       6 . The sealing arrangement according to  claim 1 , in which the first and second components are annular and bound a gap between them by respective confronting annular faces of the first and second components, and a plurality of sealing elements are arranged in a circle that extends around the confronting annular faces.  
   
   
       7 . The sealing arrangement according to  claim 6 , in which the first and second components are gas turbine components.  
   
   
       8 . The sealing arrangement according to  claim 6 , in which the first and second components are internal casings of a gas turbine.  
   
   
       9 . A method of actuating a face seal between mutually confronting machine components in a machine capable of operation at elevated temperatures, comprising the step of: providing a temperature-sensitive retention means to enable a once-only actuation of the face seal after assembly of the machine when the machine components are operating at the elevated temperatures for the first time.