Machine with Abradable Ridges and Method

Abstract

A machine having a fixed part including a portion with a smooth surface is provided. The machine also includes a rotating part configured to rotate relative to the fixed part, the rotating part directly facing the portion of the fixed part, and plural ridges formed on the portion of the fixed part directly facing the rotating part, the plural ridges comprising an abradable material, wherein the abradable material is configured to be inoperable at temperatures above about 1000° C.

1 . A machine comprising:
 a fixed part comprising a portion with a smooth surface;   a rotating part configured to rotate relative to the fixed part, the rotating part directly facing the portion of the fixed part; and   plural ridges formed on the portion of the fixed part directly facing the rotating part, the plural ridges comprising an abradable material, wherein the abradable material is configured to be inoperable at temperatures above about 1000° C., wherein at least one ridge of the plural ridges is curved.   
     
     
         2 . The machine of  claim 1 , wherein the entire of at least one ridge of the plural ridges is continuously curved. 
     
     
         3 . The machine of  claim 1 , wherein all of the plural ridges are continuously curved. 
     
     
         4 . The machine of  claim 1 , wherein the plural ridges are configured to be inoperable at temperatures above about 400° C. 
     
     
         5 . The machine of  claim 1 , wherein the abradable material is plastic or metal based. 
     
     
         6 . The machine of  claim 5 , wherein the plastic abradable material comprises one or more of polytetrafluoroethylene (PTFE), polyimide or Polyester. 
     
     
         7 . The machine of  claim 5 , wherein the metallic abradable material comprises one or more of AlSi, AlSi and Polyester, or NiCrFeBNAl. 
     
     
         8 . The machine of  claim 1 , wherein the abradable material covers a region of the portion of the fixed part that spans one third or less of an axial span of the rotating part. 
     
     
         9 . The machine of  claim 1 , further comprising:
 a diaphragm configured to enclose the rotating part, wherein the entire diaphragm is made of the abradable material.   
     
     
         10 . The machine of  claim 1 , wherein a cross section of at least one ridge of the plural ridges is a rectangle or a triangle. 
     
     
         11 . The machine of  claim 10 , wherein a height of the rectangular or triangular ridges is between about 0.1 to about 0.5 mm. 
     
     
         12 . The machine of  claim 1 , wherein the rotating part further comprises:
 plural blades disposed on the rotating part, wherein tips of the plural blades are configured to touch one or more of the plural ridges when the rotating part rotates and wherein the tips of the plural blades are not treated to include the abrasive material.   
     
     
         13 . The machine of  claim 1 , wherein the machine is an open shroud centrifugal compressor and an operating temperature of the centrifugal compressor is less than about 200° C. 
     
     
         14 . A diaphragm of a compressor, the diaphragm comprising:
 a fixed part configured to accommodate at least an impeller of the compressor and comprising a portion with a smooth surface; and   an abradable layer formed on the portion with the smooth surface of the fixed part, wherein the abradable layer is machined to form plural ridges directly facing the impeller, the plural ridges comprising an abradable material, wherein the abradable material is configured to be inoperable at temperatures above about 1000° C., and wherein at least one ridge of the plural ridges is continuously curved.   
     
     
         15 . The diaphragm of  claim 14 , wherein the abradable material is plastic or metal based. 
     
     
         17 . The diaphragm of  claim 15 , wherein the plastic abradable material comprises one or more of polytetrafluoroethylene (PTFE), polyimide, or Polyester and the metallic abradable material comprises one or more of AlSi, AlSi and Polyester, or NiCrFeBNAl. 
     
     
         18 . A method of depositing an abradable material on a diaphragm of a machine, the method comprising:
 identifying in the diaphragm a portion with a smooth surface that directly faces a rotating part of the machine;   depositing an abradable layer on the portion directly facing the rotating part, the abradable layer comprising an abradable material, wherein the abradable material is configured to be inoperable at temperatures above about 1000° C.; and   machining plural ridges in the abradable layer such that at least one ridge of the plural ridges is curved.   
     
     
         19 . The method of  claim 18 , further comprising:
 machining all of the plural ridges to be continuously curved.   
     
     
         20 . The method of  claim 18 , further comprising:
 preparing the abradable material to be plastic or metal based, wherein the plastic abradable material comprises one or more of polytetrafluoroethylene (PTFE), polyimide, or Polyester and the metallic abradable material includes one or more of AlSi, AlSi and Polyester, or NiCrFeBNAl.