The pumping principle

The 2000 series pumps are available in two separate designs (G2000 and U2000), both of which utilise the unique SPX Flow Vane pump concept, with the G2000 range designed as a fixed flow pump whereas the U2000 range is designed to be a variable flop pump without the need for any form of speed variation. The eccentricity between the shaft and rotor cause the chambers between the rotor and blades to vary in size as the pump rotates. The liquid entering the pump is guided into the ends of the rotor and then back out through the discharge port. There are eight pumping sectors and the illustration shows how the sector increases and decreases in size during rotation. Each sector in turn acts in the same manner, causing the continuous pumping

action.

Unlike a conventional vane pump the blade tip is not rotating at high peripheral speeds against a liner (which could cause a rapid wear to the blade tip). The 2000 Series blades are gently sliding along a flat inside the rotor thus reducing wear and maintaining high volumetric efficiency. Variable flow is achieved by changing the eccentricity between the shaft and the rotor. As the eccentricity is decreased, the volume of the chambers decreases thus lowering the flow rate. When the shaft and rotor are concentric there is no pumping action, no flow and no hydraulic horsepower absorbed. Reverse flow can also be achieved by increasing the eccentricity over the shaft instead of under the shaft.

This pumping principle has a low shear rate which is important for blending lube oils or pumping shear sensitive fluids such as oily water mixtures to a separator for example.