Impeller for centrifugal pumps

Abstract

An impeller for centrifugal pumps has a first disk element, functionally arranged toward the inlet, which is coaxial to and faces a second disk element, which is functionally arranged toward the delivery and is connected rigidly to the first disk element by virtue of a series of angularly spaced vanes and is provided centrally with a means for fixing to a transmission shaft. The particularity of the present invention resides in that the impeller includes a series of openings formed in the substantially peripheral region of the second disk element, between pairs of adjacent vanes, substantially at the areas subjected to the greatest axial thrust.

1 . An impeller for centrifugal pumps comprising a first disk element, functionally arranged toward the inlet, which is coaxial to and faces a second disk element, which is functionally arranged toward the delivery; said second disk element being connected rigidly to said first disk element by angularly spaced vanes and being centrally provided with a fastening means for fastening to a transmission shaft; said impeller being characterized in that it comprises openings formed in the substantially peripheral region of said second disk element, between pairs of adjacent vanes, substantially at the areas subjected to the greatest axial thrust. 
     
     
         2 . The impeller according to  claim 1 , characterized in that the radially peripheral side of each of said openings extends at a distance that is shorter than that of the peripheral edge of said second disk element, with respect to the rotation axis of said impeller. 
     
     
         3 . The impeller according to  claim 1 , characterized in that said openings are constituted by contoured slots that are formed in the substantially peripheral region of said second disk element, between pairs of adjacent vanes; the radially peripheral side of each of said contoured slots having an arc-like profile with a convexity facing said rotation axis. 
     
     
         4 . The impeller according to  claim 3 , characterized in that each of said contoured slots has a contoured profile that is opposite with respect to said arc-like profile. 
     
     
         5 . The impeller according to  claim 4 , characterized in that said contoured profile has a curved portion with a convexity facing said rotation axis. 
     
     
         6 . The impeller according to  claim 4 , characterized in that said contoured profile has a curved portion with a convexity facing the outside of said second disk element. 
     
     
         7 . The impeller according to  claim 4 , characterized in that said arc-like profile and said contoured profile are joined by at least one substantially radially extended tab. 
     
     
         8 . The impeller according to  claim 1 , characterized in that said openings are constituted by through holes formed in the substantially peripheral region of said second disk element, between pairs of adjacent vanes. 
     
     
         9 . The impeller according to  claim 1 , characterized in that the centers of said through holes are formed substantially along a circular arc that is centered with respect to said rotation axis. 
     
     
         10 . The impeller according to  claim 1 , characterized in that the centers of said through holes are formed substantially along two or more circular arcs that are concentric and centered with respect to said rotation axis. 
     
     
         11 . The impeller according to  claim 1 , characterized in that the centers of said through holes are formed substantially along circular arcs, the center of which is located outside said second disk element. 
     
     
         12 . The impeller according to  claim 1 , characterized in that said fastening means comprises a hub mechanically associated with said transmission shaft; said hub being opposite with respect to a collar having a larger diameter than the diameter of said rotation axis; said collar being provided on said first disk element. 
     
     
         13 . The impeller according to  claim 1 , characterized in that said second disk element has a diameter that is substantially equal to, or smaller than, the diameter of said first disk element. 
     
     
         14 . A centrifugal pump comprising a substantially hollow body that accommodates at least one impeller that is fastened to a transmission shaft which can rotate about a rotation axis; said transmission shaft being rotated by a motor means; said impeller comprising a first disk element, functionally arranged toward the inlet, which is coaxial to and faces a second disk element, which is functionally arranged toward the delivery; said second disk element being connected rigidly to said first disk element by angularly spaced vanes and being centrally provided with a fastening means for fastening to a transmission shaft; said impeller being characterized in that it comprises openings formed in the substantially peripheral region of said second disk element, between pairs of adjacent vanes, substantially at the areas subjected to the greatest axial thrust.