Radial compressor

Abstract

A pair of one piece cast impellers having radially extending curved and twisted three dimensional blades and being in a compressor housing which is connected to a drive motor and the impellers being mounted onto a motor drive shaft by jamming or press fitting the impellers on the shaft to provide a two stage radial compressor wherein the drive motor ( 5 ), a drive shaft ( 14 ) on which there a arranged two impellers ( 10, 12 ) there is envisaged that the drive motor ( 5 ) is a fast-running asynchronous motor with a speed in excess of 10,000 rpm and a power of around 5 to 10 kW.

1 . A small compact compressor impeller ( 10 ,  12 ;  41 ,  42 ) having a hub ( 17 ) and a plurality of radially extending impeller blades ( 26 ) connected to the hub ( 17 ) and a shroud ( 19 ) surrounding the impeller blades ( 26 ), characterised by said hub ( 17 ) having a bore ( 13 ;  43 ,  44 ) sized to be jammed or press fitted onto a drive shaft ( 14 ; 50 ), wherein said sizing provides contact between an interior of said bore and an exterior of said shaft said contact immobilizing the impeller relative to said shaft. 
   
   
       2 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 1  characterised in that the impeller blades ( 26 ) are integral with the hub ( 17 ). 
   
   
       3 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 1  characterised by the impeller blades being spatially curved and three-dimensional impeller blades ( 26 ). 
   
   
       4 . The impeller ( 41 ,  42 ) of  claim 1  characterised in that the hub bore ( 43 ,  44 ) has a frustum section extending at least 75% of the length of the hub bore. 
   
   
       5 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 1  characterised in that the impeller shroud ( 19 ) has a plurality of balancing connections ( 36 ) to bring the center of gravity of the impeller to the axis of rotation. 
   
   
       6 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 5  characterised in that the balancing connections are a plurality of threaded holes ( 36 ) around the periphery of the impeller inlet. 
   
   
       7 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 1  characterised in that the impeller is a one piece impeller. 
   
   
       8 . The impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 7  characterised in that the impeller is a one-piece cast aluminum alloy impeller. 
   
   
       9 . The small compact compressor impeller ( 10 ,  12 ;  41 ,  42 ) of  claim 1  where said impeller is in a two-stage radial compressor, and is axially mounted on the motor drive shaft ( 14 ;  50 ) and a second impeller ( 10 ,  12 ;  41 ,  42 ) is axially mounted on the drive ( 14 ;  50 ) characterised by said second impeller ( 10 ,  12 ;  41 ,  42 ) having a bore ( 13 ;  43 ,  44 ) sized so that said impeller is jammed or press fitted onto said shaft; and wherein said sizing provides a tight fit between the shaft and impeller to secure the impeller to the shaft. 
   
   
       10 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 9  characterised in that the impellers are mounted on the motor drive shaft ( 14 ;  50 ) that is connected to a fast running motor with a speed in excess of 10,000 rpm and a power of about 5 to 10 kw. 
   
   
       11 . The impellers of  claim 9  characterised in that the impellers are in a two-stage radial compressor having a drive motor ( 5 ), a drive shaft ( 14 ,  50 ), on which two impellers ( 10 ,  12 ;  41 ,  42 ) are arranged. 
   
   
       12 . The impellers of  claim 9 , characterised in that between the impellers ( 10 ,  12 ;  41 ,  42 ) there is arranged a tolerance ring ( 34 ). 
   
   
       13 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 9  characterised in that the impellers ( 10 ,  12 ;  41 ,  42 ) have a plurality of balancing bores ( 36 ) into which balancing members may be selectively attached. 
   
   
       14 . The impellers ( 10 ,  12 ;  41 ,  42 ) of,  claim 9  characterised in that downstream of the impellers there is arranged an outlet diffuser ( 18 ,  20 ). 
   
   
       15 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 14 , characterised in that the outlet diffuser ( 18 ,  20 ) is designed to have parallel walls and no blades. 
   
   
       16 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 9  characterised in that the shaft ( 14 ,  50 ) is held in two roller bearings ( 16 ) one of which is mounted between the impellers ( 10 ,  12 ;  41 ,  42 ) and the drive motor ( 5 ) and the other on the drive motor side facing away from the impellers. 
   
   
       17 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 9  characterised in that, for holding the drive shaft ( 14 ,  50 ), roller bearings ( 16 ) are used whose bearing rings are made of steel and whose rollers are made or ceramics. 
   
   
       18 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 9  characterised in that a balancing disk ( 38 ) is arranged on the drive motor ( 5 ) side facing away from the impellers. 
   
   
       19 . The impellers ( 10 ,  12 ;  41 ,  42 ) of  claim 18 , characterised in that the balancing disk ( 38 ) is in a heat-conducting connection with a neighbouring roller bearing ( 16 ). 
   
   
       20 . A small compact compressor shaft ( 50 ) having a shaft end adapted to be connected to a motor, said shaft having an end opposite the end adapted to be connected to the motor, said shaft characterised by a frustum section ( 52 ,  53 ) is sized to be press fit or jammed into an impeller bore ( 43 ,  44 ) of impeller ( 41 ,  42 ) wherein said sizing provides a tight fit between said shaft ( 50 ) and impeller ( 41 ,  42 ) to secure the impeller ( 41 ,  42 ) to the shaft ( 50 ).