Rotodynamic pump

A canned pump-motor-unit, whose motor consists of a stator and a rotor, the stator being separated from the rotor by a magnetically permeable separation wall, and whose pump consists of an impeller and a pump housing, the impeller forming a unit with the rotor of the motor, said pump-motor unit having co-axial through flow from one axial end to the other, whereby fluid enters a suction conduit, passes the rotor to an impellar inlet, accelerates within the impeller and finally exits the pumphousing, said unit's separation wall having a spherical portion which separates a wet part from a dry part of the pump, the motor having a stator with coils arranged in the dry part, said stator forming a spherical magnetic gap with the rotor, the rotor being built as a spherical ring made mainly of ferromagnetic metal, an inner bore of which forms a part of the suction conduit characterized in that

• (a) the impeller (8) being pivoted radially and axially in the direction of the suction side (13b);
• (b) the bearing consisting of a rotating spherical concave bearing cap (9) and a stationary spherical convex member (6) with a spherical sliding surface, the surface defining a center of rotation (6a);
• (c) said sliding bearing (6,9) being positioned within the bore (10a) of said rotor (10);
• (d) the diameter of the bearing (6,9) being considerably smaller than the diameter of the bore (10a) of the rotor (10);
• (e) the rotor (120) being mounted on the impeller (8);
• (f) the center of rotation (6a) being positioned between the two axial ends of the spherical portion of the separation wall (4);
• (g) the separation wall (4) being funnel-shaped with increasing diameter from the small diameter part forming a suction conduit (4e) to maximum diameter in the equatorial plane (6c) containing the center of rotation (6a);
• (h) the spherical convex member (6) of the bearing being fixed on a stationary pedestal (7) located in the suction conduit (4e, 13b);
• (i) said pedestal (7) allowing almost free throughflow of the fluid conveyed;
• and
• (j) the coils (2a, 2b, 2c) being arranged around the separation wall (4), a considerable part of the coils being in thermal contact with said separation wall (4).