An enhanced pump assembly includes an impeller and volute casing designed to provide high operating pressures (“P”) and flow rates (“Q”) with low energy usage. The impeller has a central shaft carrying radially projecting curved primary vanes, and each primary vane also has a twist in the radial direction. Secondary impeller vanes define triangular connecting fillet-like wall segments connecting each primary vane to the impeller shaft. The casing of the pump has a slight spiral deviation so that the pump chamber's radial sidewall flares away from the swept area of the impeller's vanes to define a fluid outlet that contributes to higher P-Q performance, especially when pumping colder fluids.
1. A pump assembly configured to pressurize a fluid comprising:
a volute defining a fluid inlet for receiving the fluid;
a casing configured with the volute to define a pumping chamber that is in fluid communication with said inlet;
a rotatably supported impeller configured operate within said pumping chamber,
a volute fluid passage communicating the pump chamber and the fluid outlet for discharging fluid medium under pressure during a rotation of the impeller;
wherein said impeller has a central axis of rotation and a central shaft aligned along said impeller's axis of rotation and carrying a plurality of radially projecting curved primary vanes;
wherein each primary vane has a twist in the radial direction so that each vane has provides an angled, convex leading surface;
wherein said impeller also has a plurality of radially projecting secondary vanes affixed to said central shaft such that each secondary vane is also aligned with and affixed to said radially projecting curved primary vanes;
wherein said volute has an exterior sidewall that has a constant internal first radius over a first sidewall portion and transitions to a second sidewall portion of increasing radius;
wherein said second sidewall portion defines a first end at a sidewall transition point which is tangent to said constant radius sidewall segment, and defines a second end which is tangent to said volute's fluid outlet and has a second radius that is greater than said first radius.
2. The pump assembly of claim 1 , wherein said impeller's secondary impeller vanes are each configured to define a triangular connecting fillet-like wall segment connected to a primary vane and to the impeller shaft.
3. The pump assembly of claim 1 , wherein said impeller's secondary impeller vanes are each twisted so that the leading surface of the secondary vane is angled or twisted to match the primary vane's leading surface and define a contiguous surface across both the primary vane and it's secondary vane.
4. The pump assembly of claim 1 , wherein said pump volute's sidewall defines a spiral deviation wherein the pump chamber's radial sidewall flares away from the swept area of the impeller's vanes and defines a fluid outlet that contributes to higher P-Q performance, especially when pumping colder fluids.
5. The pump assembly of claim 1 , wherein said volute sidewall has a constant internal diameter or circular profile for approx. 260 degrees, providing constant clearance with impeller and then, approaching the outlet, transitions to a gradually increasing clearance all the way to the outlet, where the casing radius is 1.6 times the radius of the casing sidewall's circular profile.
6. The pump assembly of claim 1 , wherein said volute's inlet is axially aligned with said impeller's central axis of rotation in a bottom inlet configuration.
7. The pump assembly of claim 1 , wherein said volute's inlet is axially aligned with said impeller's central axis of rotation in a side inlet, top feed configuration.
8. The pump assembly of claim 1 , wherein said volute's inlet comprises a lumen with a transition from lateral flow to vertical flow, where the vertical flow is axially aligned with said impeller's central axis of rotation in a side inlet, bottom feed configuration.
9. The pump assembly of claim 1 , wherein said impeller carries three primary impellers spaced at 120 degree intervals around the impeller shaft's central axis.
10. The pump assembly of claim 9 , wherein said impeller carries three secondary impeller vanes, and wherein each of the secondary impellers are axially aligned with a single corresponding primary impeller.
11. The pump assembly of claim 1 , wherein said impeller's primary vanes are each curved in an arc to provide a convex leading surface that terminates in a distal vane tip.
12. The pump assembly of claim 11 , wherein said impeller's primary vanes each have a substantially planar upper surface which is parallel to and opposite a substantially planar lower surface and perpendicular to said impeller's central axis of rotation.
13. The pump assembly of claim 12 , wherein said impeller primary vane upper surface carries a raised dimple or protuberance having a height selected to maintain a selected clearance between said impeller vane and the interior of the pumping chamber.
14. The pump assembly of claim 12 , wherein said impeller primary vane lower surface carries a raised dimple or protuberance having a height selected to maintain a selected clearance between said impeller vane and the interior of the pumping chamber.
15. The pump assembly of claim 1 , further comprising an electric motor configured to drive a shaft having a distal end, and wherein said impeller has an aperture or coupling configured to receive and be driven by said motor shaft's distal end.
16. An impeller adapted for use in a centrifugal pump assembly having a volute, an inlet and an outlet, comprising:
a central shaft and a central axis of rotation, wherein said shaft is aligned along said impeller's axis of rotation;
a plurality of radially projecting curved primary vanes carried by said central shaft;
wherein each primary vane has a twist in the radial direction so that each vane has provides an angled, convex leading surface;
a plurality of radially projecting secondary vanes affixed to said central shaft such that each secondary vane is also aligned with and affixed to said radially projecting curved primary vanes.
17. The impeller of claim 16 , wherein said impeller's secondary impeller vanes are each twisted so that the leading surface of the secondary vane is angled or twisted to match the primary vane's leading surface and define a contiguous surface across both the primary vane and it's secondary vane.