Thrust plate for butterfly valve

Abstract

A thrust plate for a butterfly valve includes a thrust plate body that defines a recess that extends between a bottom thrust surface, side walls, and an open top. There is a nickel-based or cobalt-based wear-resistant coating located on the bottom thrust surface. The wear-resistant coating is harder than the thrust plate body.

What is claimed is: 
     
         1 . A thrust plate for a butterfly valve, the thrust plate comprising:
 a thrust plate body defining a recess that extends between a bottom thrust surface, side walls, and an open top; and   a nickel-based or cobalt-based wear-resistant coating located on the bottom thrust surface, the wear-resistant coating being harder than the thrust plate body.   
     
     
         2 . The thrust plate as recited in  claim 1 , wherein the wear-resistant coating is a nickel-based alloy. 
     
     
         3 . The thrust plate as recited in  claim 1 , wherein the wear-resistant coating includes chromium boride. 
     
     
         4 . The thrust plate as recited in  claim 1 , wherein the wear-resistant coating includes chromium carbide. 
     
     
         5 . The thrust plate as recited in  claim 1 , wherein the thrust plate body is stainless steel. 
     
     
         6 . The thrust plate as recited in  claim 5 , wherein a ratio of a hardness of the wear-resistant coating to a hardness of the stainless steel is at least 2.3. 
     
     
         7 . The thrust plate as recited in  claim 6 , wherein the recess defines a recess diameter (RD 1 ) and the wear-resistant coating defines an average coating thickness (CT), and ratio RD 1 /CT is between 33.2 and 56.67. 
     
     
         8 . The thrust plate as recited in  claim 7 , wherein the recess defines a recess depth (RD 2 ) and the wear-resistant coating defines an average coating thickness (CT), and a ratio RD 2 /CT is between 5 and 10.33. 
     
     
         9 . The thrust plate as recited in  claim 8 , wherein the thrust plate body, with the exception of the bottom thrust surface, is free of the wear-resistant coating. 
     
     
         10 . The thrust plate as recited in  claim 1 , wherein the thrust plate body is a material selected from a group consisting of nickel-based alloy, cobalt-based alloy and steel, and the wear-resistant coating is a nickel-based alloy. 
     
     
         11 . A butterfly valve comprising:
 a valve housing defining a flow passage there through;   a shaft extending in the valve housing and including a butterfly disk mounted thereon within the flow passage;   a thrust plate including a thrust plate body defining a recess that receives an end of the shaft, and the recess extends between a bottom thrust surface, side walls, and an open top; and   a wear-resistant coating located on the bottom thrust surface.   
     
     
         12 . The butterfly valve as recited in  claim 11 , wherein the wear-resistant coating consists essentially of 0.5-1.0 wt. % carbon, 12-18 wt. % chromium, 2.5-4.5 wt. % boron, 3.5-5.5 wt. % silicon, 3.5-5.5 wt. % iron, up to 0.2 wt. % cobalt, and a remainder of nickel 
     
     
         13 . The butterfly valve as recited in  claim 11 , wherein the thrust plate body is stainless steel. 
     
     
         14 . The butterfly valve as recited in  claim 13 , wherein a ratio of a hardness of the wear-resistant coating to a hardness of the stainless steel is at least 2.3. 
     
     
         15 . The butterfly valve as recited in  claim 14 , wherein the recess defines a recess diameter (RD 1 ) and the wear-resistant coating defines an average coating thickness (CT), and ratio RD 1 /CT is between 33.2 and 56.67. 
     
     
         16 . The butterfly valve as recited in  claim 15 , wherein the recess defines a recess depth (RD 2 ) and the wear-resistant coating defines an average coating thickness (CT), and a ratio RD 2 /CT is between 5 and 10.33. 
     
     
         17 . The butterfly valve as recited in  claim 16 , wherein the thrust plate body, with the exception of the bottom thrust surface, is free of the wear-resistant coating. 
     
     
         18 . The butterfly valve as recited in  claim 11 , wherein the flow passage defines a central axis, and a long axis of the shaft is non-perpendicular to the central axis. 
     
     
         19 . The butterfly valve as recited in  claim 11 , wherein the recess defines a recess diameter (RD 1 ) and a recess depth (RD 2 ) and the wear-resistant coating defines an average coating thickness (CT) such that a ratio RD 1 /CT is between 33.2 and 56.67 and a ratio RD 2 /CT is between 5 and 10.33. 
     
     
         20 . A method of installing a thrust plate on a butterfly valve, the method comprising:
 securing a thrust plate to a valve housing that defines a flow passage there through such that an end of a shaft, which extends within the valve housing and includes a butterfly disk mounted thereon, is received into a recess of the thrust plate body, the recess extends between a bottom thrust surface, side walls, and an open top, and the bottom thrust surface includes a wear-resistant coating thereon.