Centrifugal pump, in particular a spirally-housed centrifugal pump for a heat exchange medium

Abstract

In a centrifugal pump—in particular a spiral-casing centrifugal pump—for a heat carrier medium, comprising a spiral casing ( 14 ) having an impeller ( 40 ), a casing cover ( 18 ) and an associated casing attachment portion ( 34 ) for a pump shaft ( 35, 36, 36 a ) provided with a shaft bearing ( 76, 76 a ) near the spiral casing ( 14 ) and a shaft seal ( 56 ) disposed at a spacing in relation to the shaft bearing in a sealing chamber ( 48 ), parts of the casing cover ( 18 ) are a bearing cup ( 28 ) accommodating the shaft bearing ( 76, 76 a ), a tubular portion ( 32 ) surrounding the pump shaft ( 35, 36, 36 a ) as a heat barrier and support ribs ( 56 ) or the like profile elements arranged at a spacing relative to each other in the peripheral direction. The bearing cup ( 28 ) is held at an axial spacing towards the impeller ( 40 ) by the tubular portion ( 32 ) surrounding the pump shaft ( 35, 36, 36 a ), and the casing attachment portion ( 34 ) attached to the casing cover ( 18 ) or an edge ring ( 30 ) carried by the support ribs ( 26 ) thereof delimits the sealing chamber ( 48 ) for the shaft seal ( 56 ).

1 . A centrifugal pump, in particular a spiral-casing centrifugal pump, for a heat carrier medium, comprising a spiral casing ( 14 ) having an impeller ( 40 ), a casing cover ( 18 ) and an associated casing attachment portion ( 34 ) for a pump shaft ( 35 ,  36 ,  36   a ) provided with a shaft bearing ( 76 ,  76   a ) near the spiral casing ( 14 ) and a shaft seal ( 56 ) disposed at a spacing in relation to the shaft bearing in a sealing chamber ( 48 ), characterised in that a bearing cup ( 28 ) accommodating the shaft bearing ( 76 ,  76   a ), a tubular portion ( 32 ) surrounding the pump shaft ( 35 ,  36 ,  36   a ) as a heat barrier and support ribs ( 56 ) or the like profile elements arranged at a spacing relative to each other in the peripheral direction are parts of the casing cover ( 18 ).  
   
   
       2 . A centrifugal pump as set forth in  claim 1  characterised in that the bearing cup ( 28 ) is held at an axial spacing towards the impeller ( 40 ) by the tubular portion ( 32 ) surrounding the pump shaft ( 35 ,  36 ,  36   a ).  
   
   
       3 . A centrifugal pump as set-forth in  claim 1  or  claim 2  characterised in that the casing attachment portion ( 34 ) attached to the casing cover ( 18 ) or an edge ring ( 30 ) carried by the support ribs ( 26 ) thereof delimits the sealing chamber ( 48 ) for the shaft seal ( 56 ).  
   
   
       4 . A centrifugal pump as set forth in  claim 3  characterised in that at their ends remote from the base region ( 20 ) of the casing cover ( 18 ) the support ribs ( 26 ) are connected by the edge ring ( 30 ) surrounding the longitudinal axis (A) of the pump.  
   
   
       5 . A centrifugal pump as set forth in one of claims  1  through  4  characterised in that the support ribs ( 26 ) are inclined at an angle (w) to the longitudinal axis (A) of the pump from the base region ( 20 ) of the casing cover ( 18 ) towards the shaft seal ( 56 ).  
   
   
       6 . A centrifugal pump as set forth in  claim 5  characterised by an angle (w) of between 30° and 60°.  
   
   
       7 . A centrifugal pump as set forth in one of claims  1  through  6  characterised in that the cross-sectional height (h) of the support ribs ( 26 ) which preferably extend in axial planes (E) passing radially through the longitudinal axis (A) of the pump increases towards the sliding ring seal ( 56 ).  
   
   
       8 . A centrifugal pump as set forth in one of claims  1  through  7  characterised in that the sealing chamber ( 48 ) adjoins the shaft bearing ( 76 ,  76   a ).  
   
   
       9 . A centrifugal pump as set forth in one of claims  1  through  8  characterised in that at least one abutment step ( 28 ) directed away from the spiral casing ( 24 ) for a further pump portion ( 96 ) is arranged at the casing cover ( 18 ).  
   
   
       10 . A centrifugal pump as set forth in  claim 9  characterised in that the abutment step is a front ring ( 22 ) formed on the casing cover ( 18 ).  
   
   
       11 . A centrifugal pump as set forth in  claim 9  or  claim 10  characterised in that the abutment step or the front ring ( 22 ) projects from an annular flange ( 21 ) which surrounds the support ribs ( 26 ) and which is disposed at the transition thereof to a base region ( 20 ) of the casing cover ( 18 ).  
   
   
       12 . A centrifugal pump comprising a sealing ring ( 59 ) of the shaft seal which is in the form of a sliding ring seal ( 56 ), the sealing ring extending peripherally at a counterpart ring ( 60 ) provided at the housing side, as set forth in one of claims  1  through  11 , characterised in that the counterpart ring ( 60 ) for the sealing ring ( 59 ) is arranged in a shaped stub portion ( 64 ) of the casing attachment portion ( 34 ), the stub portion projecting axially into the sealing chamber ( 48 ), and associated with the stub portion is at least one passage ( 58 ) inclined with respect to the longitudinal axis (A) of the pump, with a closure screw ( 52 ) closing the passage.  
   
   
       13 . A centrifugal pump as set forth in  claim 12  characterised by an angle (z) between the longitudinal axis (A) of the pump and the longitudinal axis (B) of the passage ( 53 ) of about 45°.  
   
   
       14 . A centrifugal pump as set forth in  claim 12  or  claim 13  characterised by an axial length (f) of the stub portion ( 64 ) which corresponds approximately to half the axial length (e 1 ) of the sealing chamber ( 48 ).  
   
   
       15 . A centrifugal pump as set forth in one of claims  1  through  14  characterised in that the shaft bearing is in the form of a plain bearing ( 76 ) with a ratio of the length (g) of the bearing bush ( 77 ) to the diameter (d) of the pump shaft ( 35 ,  36 ,  36   a ) of between about 1.5 and 2.0, preferably about 1.8.  
   
   
       16 . A centrifugal pump as set forth in  claim 15  characterised in that the bearing bush ( 77 ) of the plain bearing ( 76 ,  76   a ) is adapted to be dismantleable.  
   
   
       17 . A centrifugal pump as set forth in  claim 15  or  claim 16  characterised in that the plain bearing ( 76 ,  76   a ) or its bearing bush ( 77 ) is externally embraced approximately at its longitudinal center by a clamping or tolerance ring ( 80 ) which engages into the bearing cup ( 28 ).  
   
   
       18 . A centrifugal pump as set forth in  claim 17  characterised in that the width (n) of the clamping or tolerance ring ( 80 ) corresponds to a fraction of the length (g) of the bearing bush ( 77 ).  
   
   
       19 . A centrifugal pump as set forth in  claim 18  characterised in that the width (n) of the external clamping or tolerance ring ( 80 ) corresponds approximately to between a fifth and a sixth of the length (g) of the bearing bush ( 77 ).  
   
   
       20 . A centrifugal pump as set forth in one of claims  15  through  19  characterised in that the plain bearing ( 76   a ) includes an inner bearing sleeve ( 82 ) surrounded by a bearing bush ( 77 ) at the bearing cup side ( FIGS. 6 and 7 ).  
   
   
       21 . A centrifugal pump as set forth in one of claims  15  through  20  characterised in that within the plain bearing ( 76   a ) the pump shaft ( 35 ,  36   a ) is embraced by at least one tolerance ring ( 80   i ) which engages into the pump shaft.  
   
   
       22 . A centrifugal pump as set forth in one of claims  17  through  21  characterised in that provided on respective sides of the outer tolerance ring ( 80 ), viewed in longitudinal section of the centrifugal pump ( 10   a ), is a respective inward tolerance ring ( 80   i ) which engages into the pump shaft ( 35 ,  36   a ).  
   
   
       23 . A centrifugal pump as set forth in one of claims  15  through  19  characterised in that the plain bearing ( 76 ) includes a bearing bush ( 77 ) at the bearing cup side, with a slidable internal peripheral surface portion ( 78 ) embracing the pump shaft ( 36 ).  
   
   
       24 . A centrifugal pump as set forth in  claim 23  characterised by an internal peripheral surface portion ( 28 ) of the plain bearing ( 76 ) comprising carbon ( FIGS. 4 and 5 ).  
   
   
       25 . A centrifugal pump as set forth in  claim 23  or  claim 24  characterised by a hardened pump shaft ( 36 ) or a corresponding shaft portion which is associated with the bearing bush ( 77 ).  
   
   
       26 . A centrifugal pump as set forth in one of claims  1  through  25  characterised in that the sliding ring seal ( 56 ) embraces a shaft sleeve ( 89 ) at the shaft side, wherein at least one O-ring ( 88 ) is provided between the shaft sleeve ( 89 ) and the pump shaft ( 36 ,  36   a ).  
   
   
       27 . A centrifugal pump as set forth in one of claims  1  through  26  characterised in that a rearward shaft bearing ( 68 ) for the pump shaft ( 36 ,  36   a ) is arranged in the casing attachment portion ( 34 ) at an axial spacing relative to the sliding ring seal ( 56 ) outside the sealing chamber ( 48 ).  
   
   
       28 . A centrifugal pump as set forth in  claim 27  characterised in that at least one hollow space ( 66 ) is arranged between the sealing chamber ( 48 ) and the shaft bearing ( 68 ) in the casing attachment portion ( 34 ).  
   
   
       29 . A centrifugal pump as set forth in one of claims  1  through  28  characterised in that the pump shaft ( 36   a ) is in the form of a plug-in stub shaft with clamping ring ( 92 ).  
   
   
       30 . A centrifugal pump as set forth in one of claims  8  through  29  characterised in that the spiral casing ( 14 ) and the bearing carrier casing ( 16 ) are embraced by a spacer ( 96 ) which butts against the abutment step or steps or the front ring ( 22 ) respectively and it is attached to a motor ( 100 ).