Patent ID: 6966749

Claim:
A centrifugal pump comprising: (a) a pump case having a forward wall and a rearward wall, the rearward wall defining a central opening for a drive shaft; (b) a rotatable impeller disposed within the pump case, the impeller having a center, a support wall and impeller blades, the support wall having a forward side and a rearward side; (c) a drive shaft disposed throughout the central opening of the rearward wall of the pump case and attached to the rearward side of the impeller support wall for rotating the impeller; (d) a primary drive shaft seal disposed around the central opening of the rearward wall of the pump case to seal the drive shaft to the pump case; (e) at least one groove defined in the rearward wall of the pump case, the at least one groove radiating outwardly from the primary drive shaft seal to carry liquids to and from the primary drive shaft seal; and (f) at least one radial ridge disposed on the rearward side of the support wall of the impeller.