Sealing device

Abstract

A sealing device by which the leakage of fluid is further reduced by securely maintaining the adhesion between a base material and an abradable layer and further strengthening the prevention of fluid leakage is provided. The sealing device according to the present invention includes seal strips provided to either one of a rotating portion or a stationary portion forming a gap therebetween; and a coating layer provided to a base material of the rotating portion or the stationary portion so that the coating layer faces the seal strips. The coating layer is composed of an abradable layer and a bond coat layer.

1 . A sealing device for preventing fluid from leaking comprising: 
 seal strips provided to either one of a rotating component or a stationary component with a gap formed therebetween; and    a coating layer provided to a base material of the rotating component or the stationary component so that the coating layer faces the seal strips,    wherein the coating layer is composed of an abradable layer and a bond coat layer.    
   
   
       2 . The sealing device according to  claim 1 , wherein the bond coat layer is formed by high-velocity oxygen-fuel or plasma spray so as to have a porosity of 2.0% or less.  
   
   
       3 . The sealing device according to  claim 1 , wherein the bond coat layer has a linear expansion coefficient which is controlled to an intermediate value between that of a base material of the stationary component and that of the abradable layer.  
   
   
       4 . The sealing device according to  claim 1 , wherein the bond coat layer is formed of one of Ni-based alloy steel, Co-based alloy steel and a MCrAlY alloy.  
   
   
       5 . The sealing device according to  claim 1 , wherein the abradable layer is made of a composition containing any one of a NiCrAl alloy and bentonite (BN), a composition containing a NiCrFeAl alloy and bentonite (BN), and a composition containing a MCrAlY alloy and bentonite (BN).  
   
   
       6 . The sealing device according to  claim 1 , wherein the abradable layer is disposed above the bond coat layer.  
   
   
       7 . The sealing device according to  claim 1 , wherein the sealing device is applied to a fluid machinery.  
   
   
       8 . The sealing device according to  claim 7 , wherein the fluid machinery is a steam turbine provided with a turbine rotor to which buckets are implanted and nozzles vanes, in which the rotating component is composed of the turbine rotor and the buckets and the stationary component is a diaphragm inner ring and a diaphragm outer ring supporting the nozzle vanes.