Method and apparatus for increasing the adiabatic efficiency of a centrifugal compressor

Abstract

A method and apparatus for increasing the adiabatic efficiency of a centrifugal compressor is provided. The apparatus includes a soft material insert that is placed in the case of the centrifugal compressor such that the soft material faces the compressor impeller. This gap between the impeller and the soft material insert can be minimized to prevent air from escaping the compressor and thereby increasing the efficiency of the centrifugal compressor.

I claim:  
     
         1 . A method of increasing the adiabatic efficiency of a centrifugal compressor having a case with an axial compressor portion and a radial compressor portion, a rotatable impeller, an impeller shaft drivingly coupled between the impeller and a power source, the centrifugal compressor acting upon a compressible fluid, the method comprising: 
 minimizing the distance between an impeller and an interior surface of a wall of the case.    
     
     
         2 . The method of  claim 1  wherein the step of minimizing the distance between the impeller and the interior surface of the wall of the case includes inserting a material having a hardness less than that of the impeller on the interior surface of the wall of the case facing the impeller and in direct contact with the interior surface of the wall.  
     
     
         3 . The method of  claim 2  wherein the step of inserting a material having a hardness less than that of the impeller on the interior surface of the wall of the case facing the impeller and in direct contact with the interior surface of the wall includes inserting the material on the axial compressor portion of the interior surface or the wall of the case.  
     
     
         4 . The method of  claim 3  wherein the step of inserting the material on the axial compressor portion of the interior surface of the wall of the case includes holding the material in compression.  
     
     
         5 . The method of  claim 4  wherein the step of inserting the material on the axial compressor portion of the case including serrating the surface of the material facing the impeller such that the surface is crenulated.  
     
     
         6 . The method of  claim 2  wherein the step of inserting a material having a hardness less than that of the impeller on the interior surface of the wall of the case facing the impeller and in direct contact with the interior surface of the wall includes inserting the material on the axial compressor portion and continuing on the radial compressor portion of the interior surface of wall of the case.  
     
     
         7 . The method of  claim 6  wherein the step of inserting the material on the axial compressor portion and continuing on the radial compressor portion of the interior surface of wall of the case includes holding the material in compression.  
     
     
         8 . The method of  claim 6  wherein the step of inserting the material on the axial compressor portion and continuing on the radial compressor portion of the interior surface of wall of the case includes serrating the surface of the material facing the impeller such that the surface is crenulated.  
     
     
         9 . The method of  claim 2  wherein the centrifugal compressor is a supercharger for supplying supercharged intake fluid to an engine.  
     
     
         10 . The method of  claim 2  wherein the centrifugal compressor is a turbocharger for supplying supercharged intake fluid to an engine.  
     
     
         11 . A centrifugal compressor acting upon a compressible fluid, the centrifugal compressor comprising: 
 a case having an axial compressor portion and a radial compressor portion; a rotatable impeller operable to compress the compressible fluid;    an impeller shaft on which the impeller is supported, the impeller shaft being drivingly connectable to a power source; and    a toroid insert on an interior surface or the wall of the case facing the impeller and being in direct contact with the interior surface.    
     
     
         12 . A centrifugal compressor as claimed in  claim 11  where in the toroid insert is composed of a material having a material hardness less than that of the rotatable impeller.  
     
     
         13 . A centrifugal compressor as claimed in  claim 12  wherein the toroid insert is composed of Teflon  
     
     
         14 . A centrifugal compressor as claimed in  claim 13  wherein the toroid insert is placed in the axial compressor portion of the case.  
     
     
         15 . A centrifugal compressor as claimed in  claim 14  wherein the toroid insert is adhesively bonded to the interior surface of the wall of the case in the axial compressor portion of the case.  
     
     
         16 . A centrifugal compressor as claimed in  claim 14  wherein the toroid insert is held in axial compression.  
     
     
         17 . A centrifugal compressor as claimed in  claim 14  wherein the toroid insert is held in radial compression.  
     
     
         18 . A centrifugal compressor as claimed in  claim 17  wherein the toroid insert is held in place using at least one annular retaining member.  
     
     
         19 . A centrifugal compressor as claimed in  claim 14  wherein the toroid insert is held in axial and radial compression.  
     
     
         20 . A centrifugal compressor as claimed in  claim 14  wherein the surface of the toroid insert facing the impeller is smooth.  
     
     
         21 . A centrifugal compressor as claimed in  claim 14  wherein the surface of the toroid insert facing the impeller is crenulated.  
     
     
         22 . A centrifugal compressor as claimed in  claim 12  wherein the toroid insert is placed in axial compressor portion of the case and extending to the radial compressor portion of the case.  
     
     
         23 . A centrifugal compressor as claimed in  claim 22  wherein the toroid insert is held in place using multiple torus retaining members and the multiple torus retaining members are recessed below the surface of the toroid insert that faces the impeller.  
     
     
         24 . A centrifugal compressor as claimed in  claim 23  wherein the multiple torus retaining members have a tensile strength greater than that of the toroid insert.  
     
     
         25 . A centrifugal compressor as claimed in  claim 23  wherein the toroid insert is adhesively bonded to the interior surface of the wall of the case in the axial compressor portion or the radial compressor portion of the case or both.  
     
     
         26 . A centrifugal compressor as claimed in  claim 23  wherein the surface of the toroid insert facing the impeller is smooth.  
     
     
         27 . A centrifugal compressor as claimed in  claim 23  wherein the surface of the toroid insert facing the impeller is crenulated.  
     
     
         28 . A centrifugal compressor as claimed in  claim 22  wherein the surface of the toroid insert making contact with the casing contains locating tabs that protrude from the surface of the toroid insert and extend into the wall of the casing.  
     
     
         29 . A centrifugal compressor as claimed in  claim 28  wherein the case has receiving holes on the interior surface of the wall of the case for receiving the locating tabs of the toroid insert.  
     
     
         30 . A centrifugal compressor as claimed in  claim 23  wherein the toroid insert is adhesively bonded to the interior surface of the wall of the case in the axial compressor portion or the radial compressor portion of the case or both.  
     
     
         31 . A centrifugal compressor as claimed in  claim 23  wherein the surface of the toroid insert facing the impeller is smooth.  
     
     
         32 . A centrifugal compressor as claimed in  claim 23  wherein the surface of the toroid insert facing the impeller is crenulated.  
     
     
         33 . A centrifugal compressor as claimed in  claim 28  wherein the locating tabs are torus rings that protrude from the surface of the toroid insert and extend into the wall of the casing.  
     
     
         34 . A centrifugal compressor as claimed in  claim 33  wherein the case has channels on the interior surface of the wall of the case for receiving the torus rings.  
     
     
         35 . A centrifugal compressor as claimed in  claim 22  wherein the toroid insert is held in place using multiple torus retaining members and the multiple torus retaining members are recessed below the surface of the toroid insert that faces the impeller and surface of the toroid insert making contact with the case contains locating tabs that protrude from the surface of the toroid insert and extend into the wall of the casing.  
     
     
         36 . A centrifugal compressor as claimed in  claim 35  wherein the case has receiving holes on the interior surface of the wall of the case for receiving the locating tabs of the toroid insert.  
     
     
         37 . A centrifugal compressor as claimed in  claim 35  wherein the toroid insert is adhesively bonded to the interior surface of the wall of the case in the axial compressor portion or the radial compressor portion of the case or both.  
     
     
         38 . A centrifugal compressor as claimed in  claim 35  wherein the surface of the toroid insert facing the impeller is smooth.  
     
     
         39 . A centrifugal compressor as claimed in  claim 35  wherein the surface of the toroid insert facing the impeller is crenulated.  
     
     
         40 . A centrifugal compressor as claimed in  claim 22  wherein the toroid insert is held in place using multiple torus retaining members and the multiple torus retaining members are recessed below the surface of the toroid insert facing the impeller and surface of the toroid insert making contact with the case contains locating torus rings that protrude from the surface of the toroid insert and extend into the wall of the casing.  
     
     
         41 . A centrifugal compressor as claimed in  claim 40  wherein the case has receiving channels on the interior surface of the wall of the case for receiving the locating rings of the toroid insert.  
     
     
         43 . A centrifugal compressor as claimed in  claim 40  wherein the toroid insert is adhesively bonded to the interior surface of the wall of the case in the axial compressor portion or the radial compressor portion of the case or both.  
     
     
         43 . A centrifugal compressor as claimed in  claim 40  wherein the surface of the toroid insert facing the impeller is smooth.  
     
     
         44 . A centrifugal compressor as claimed in  claim 40  wherein the surface of the toroid insert facing the impeller is crenulated.  
     
     
         45 . A centrifugal compressor claimed in  claim 12  wherein the centrifugal compressor is a supercharger for supplying supercharged intake fluid to an engine.  
     
     
         46 . A centrifugal compressor as claimed in  claim 12  wherein the centrifugal compressor is a turbocharger for supplying supercharged intake fluid to an engine.