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(11) | EP 0 406 788 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Open bladed impeller, particularly for centrifugal pump |
| (57) The present invention relates to an open bladed impeller (1), particularly for a
centrifugal pump, comprising a substantially planar disk-like supporting element (5)
having a central hub (7) adapted to be keyed to a drive shaft (3) and a plurality
of blades (6) rigidly attached to the front surface of said supporting element at
regularly angularly spaced locations thereof, wherein each blade is formed by a longitudinal
core (15) extending transversely of the main plane of said supporting element, and
has a back longitudinal edge (11) affixed to said supporting element and a front longitudinal
edge (12) adapted to cooperate with an adjacent stationary wall (13) of the casing;
the front longitudinal edge of each blade has a profile which is substantially parallel
to the inner surface of the stationary wall with such a substantially uniform axial
clearance (d) to form a free frontal skimming surface providing partial sealing with
said stationary wall. At the front longitudinal edge of each blade there is provided
a substantially planar, longitudinal flange formation which projects laterally from
said longitudinal core to extend parallel to the facing surface of the stationary
wall, to thereby increase extension of the front skimming surfaces and improve their
sealing action relative to the inner casing wall. |