Centrifugal compressor with leakage-free diffuser blades and method of assembling a centrifugal compressor

Abstract

A centrifugal compressor includes a rotor with a plurality of impellers and a stator with at least a first diaphragm, a second diaphragm, a diffuser, and a plurality of diffuser blades inside the diffuser; each diffuser blade has a tip portion, a base portion and an airfoil portion; and are located between the downstream portion of the first diaphragm and the upstream portion of the second diaphragm; the base portion of the diffuser blades is integrated in or mounted to the upstream portion of the second diaphragm, and the tip portion of the diffuser blades abuts against the downstream portion of the first diaphragm; alternatively, the base portion of the diffuser blades is integrated in or mounted to the downstream portion of the first diaphragm, and the tip portion of the diffuser blades abuts against the upstream portion of the second diaphragm.

What is claimed is: 
     
         1 . A centrifugal compressor for a fluid, comprising a rotor with a plurality of impellers and a stator with at least a first diaphragm, a second diaphragm downstream the first diaphragm, a diffuser defined between a shroud side of a downstream portion of the first diaphragm and a hub side of a upstream portion of the second diaphragm, and a plurality of diffuser blades inside the diffuser, each diffuser blade having a tip portion, a base portion and an airfoil portion between the base portion and the tip portion,
 wherein the diffuser blades are located between the downstream portion of the first diaphragm and the upstream portion of the second diaphragm,   wherein the base portion of the diffuser blades is integrated in or mounted directly or indirectly to the upstream portion of the second diaphragm so to avoid fluid flow between the base portion and the hub side of the upstream portion, and the tip portion of the diffuser blades abuts against the downstream portion of the first diaphragm so to avoid fluid flow between the tip portion and the shroud side of the downstream portion   or   wherein the base portion of the diffuser blades is integrated in or mounted directly or indirectly to the downstream portion of the first diaphragm so to avoid fluid flow between the base portion and the shroud side of the downstream portion, and the tip portion of the diffuser blades abuts against the upstream portion of the second diaphragm so to avoid fluid flow between the tip portion and the hub side of the upstream portion.   
     
     
         2 . The centrifugal compressor of  claim 1 , wherein the tip portion of each diffuser blade of the plurality is movable, resiliently movable, with respect to the first diaphragm or the second diaphragm whereto it is mounted. 
     
     
         3 . The centrifugal compressor of  claim 1 , wherein each diffuser blade of plurality comprises a first platform adjacent to the base portion and a spring acting on the first platform. 
     
     
         4 . The centrifugal compressor of  claim 1 , wherein each diffuser blade of the plurality comprises a second platform and the spring is located between the first platform and the second platform and acts on them. 
     
     
         5 . The centrifugal compressor of  claim 1 , wherein at least the base portion or the airfoil portion or the tip portion of each diffuser blade of the plurality is made of elastic material. 
     
     
         6 . The centrifugal compressor of  claim 1 , wherein the base portion and the airfoil portion and the tip portion of each diffuser blade of the plurality is made of elastic material, the same elastic material. 
     
     
         7 . The centrifugal compressor of  claim 1 , wherein each diffuser blade of the plurality comprises a snap mount for mounting it to the first diaphragm or the second diaphragm. 
     
     
         8 . A method of assembling a centrifugal compressor, wherein:
 a plurality of half-diaphragms are bundled together;   A) a half-casing or half-counter-casing is lowered on the bundle;   B) the plurality of half-diaphragms are loosened inside said half-casing or half-counter-casing; and   C) the plurality of half-diaphragms are fixed to the half-casing or half-counter-casing.   
     
     
         9 . The method of  claim 8 , wherein:
 the half-casing or half-counter-casing with half-diaphragms inside is turned upside down; and   D) a rotor of the centrifugal compressor is lowered on the turned half-casing or half-counter-casing with half-diaphragms inside.   
     
     
         10 . The method of  claim 9 , wherein
 E) a plurality of half-diaphragms are bundled together,   F) a half-casing or half-counter-casing is lowered on the bundle   G) the plurality of half-diaphragms are loosened inside the half-casing or half-counter-casing,   H) the plurality of half-diaphragms are fixed to the half-casing or half-counter-casing, and   I) the half-casing or half-counter-casing with half-diaphragms inside is lowered on the assembly.   
     
     
         11 . The method of  claim 8 , wherein diffuser blades are located between adjacent half-diaphragms and wherein the diffuser blades are compressible. 
     
     
         12 . The method of  claim 11 , wherein, one or more diffuser blades is or are compressed during bundling. 
     
     
         13 . The method of  claim 11 , wherein, one or more diffuser blades is or are mounted to half-diaphragms.