US 11,732,717 B2
Multistage centrifugal grinder pump
Michael Burke, County Wexford (IE); and Ian Cullen, County Wexford (IE)
Assigned to SULZER MANAGEMENT AG, Winterthur (CH)
Filed by Sulzer Management AG, Winterthur (CH)
Filed on Jan. 31, 2019, as Appl. No. 16/263,744.
Claims priority of application No. 18158444 (EP), filed on Feb. 23, 2018.
Prior Publication US 2019/0264690 A1, Aug. 29, 2019
Int. Cl. F04D 1/06 (2006.01); F04D 7/04 (2006.01); F04D 29/42 (2006.01); F04D 29/44 (2006.01)
CPC F04D 1/06 (2013.01) [F04D 7/045 (2013.01); F04D 29/426 (2013.01); F04D 29/445 (2013.01); F04D 29/448 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A multistage centrifugal grinder pump, comprising:
a housing including a base plate with an inner surface, a pump inlet for a fluid to be conveyed, and a pump outlet for discharging the fluid;
a grinder arranged at the pump inlet configured to grind constituents of the fluid;
a first stage impeller configured to rotate about an axial direction;
a second stage impeller configured to rotate about the axial direction;
a stationary diffusor having an inner surface and being arranged with respect to the axial direction between the first stage impeller and the second stage impeller, and the inner surface of the stationary diffuser arranged adjacent to and abutting the inner surface of the base plate to form a flow channel that surrounds the first stage impeller to enable the fluid to flow radially outwardly from the first stage impeller to the second stage impeller, and to transform kinetic energy of the fluid into pressure; and
a shaft configured to rotate the first stage impeller, the second stage impeller and the grinder,
the first stage impeller and the second stage impeller arranged in series and connected to the shaft in a torque-proof manner, and
the diffusor being a unitarily formed semi-open diffusor having a top wall and a lower surface, a radially outer annular side wall, and a bottom side facing the first stage impeller, the bottom side having an opening, the top wall arranged adjacently to the second stage impeller, the top wall having a central outlet opening surrounding the shaft, and the opening in the bottom side extending beyond the first stage impeller with respect to a radial direction, the top wall extending mainly perpendicular to the axial direction and being arranged adjacently to the second stage impeller, and the lower surface extending mainly perpendicular to the axial direction and being arranged adjacently to the first stage impeller.