Impeller for centrifugal pump, particularly for pump of the recessed impeller type, and pump with such an impeller

An impeller for a recess impeller type centrifugal pump, comprising:

• a disc,
• a plurality of vanes which extend from said disc,
• a central body, adapted for connection to a rotating shaft,
• wherein each one of said vanes has a profile with a double curvature:
• a first curvature with respect to a sectional plane that is parallel to said disc,
• a second curvature with respect to a sectional plane that is perpendicular to said disc,
• said first curvature and said second curvature having their concavity directed toward an inside of said impeller, wherein said vanes are equidistant and each one of said vanes is extended between:
• a first end, which is arranged at said central body and is at least partially monolithic therewith,
• a second end, which is arranged at the external circumference of said disc,
• wherein each one of said vanes comprises an inside curve and an outside curve, which have different curvatures:
• both when considering a sectional plane that is parallel to said disc,
• and when considering a sectional plane that is perpendicular to said disc,
• wherein said inside curve and said outside curve represent two arcs of circles with distinct centers and/or two Non Uniform Rational Basis-Splines (NURBS) with a different number of poles and/or nodes, when considering a sectional plane that is perpendicular to said disc,
• wherein each one of said vanes comprises a terminal portion, which is opposite with respect to said disc,
• wherein said terminal portion that protrudes from said inside curve comprises an extension, in a direction that is perpendicular to a tangent to said inside curve, in a point of said inside curve that is furthest from said disc, considering a sectional plane that is perpendicular to said supporting disc, and
• wherein said terminal portion protrudes from said inside curve of each one of said vanes toward the inside of the impeller, starting from the second end to a portion a distance from the first end.