Patent ID: 7112033
Filing Date: 2006-09-26
Classification: F04D

Abstract:
1. A sanitary centrifugal pump comprising: a housing having a front side, a back side, an inlet port, an outlet port, and defining a pumping chamber; an impeller positioned at least partially within the housing and connected to a shaft for rotation, the rotation of the impeller creating a first liquid flow path through the pumping chamber between the inlet port and the outlet port, and creating a high pressure area in the pumping chamber; a back plate fastened to the back side of the housing, the back plate defining a seal cavity, and a gap between the impeller and a front wall of the back plate; a mechanical seal positioned at least partially within the seal cavity and mounted in combination with the shaft and the back plate; a first seal flushing passage integrally disposed within and passing through the back plate creating a second liquid flow path between the pumping chamber and the seal cavity for cooling and flushing at least a portion of the mechanical seat disposed within the seal cavity, the first seal flushing passage delivering liquid to the seal cavity from the pumping chamber and the gap permitting flow of liquid back to the pumping chamber from the seal cavity; and second and third seal flushing passages disposed within and passing through the back plate and creating a third liquid flow path between the seal cavity and a flushing zone adjacent a stationary section of the mechanical seal, and a seal flushing drain passage extending from the flushing zone to a drainage area outside the sanitary centrifugal pump.