The D series Multistage Ring Section Centrifugal Water Pump is a utility-grade, high-pressure, ring section pump with heavy duty, segmental ring, diffuser design. Axial thrust balance device with stacked rotor construction. Suitable for boiler feed pump and high building, long distance water transferring.

A centrifugal pump works by creating a centrifugal force to move liquid through the pump, increasing the liquid’s pressure as it moves from suction through the discharge end. A multi-stage centrifugal pump contains two or more impellers in the same pump unit. Ring section pumps, which are a type of multistage centrifugal pump, have multiple stages arranged in tandem inside their casings. As the liquid passes through each stage, the pressure of the liquid increases. This is especially useful for certain applications, including boiler feed systems, municipal fire suppression (think high-rise building sprinklers, for example), amine sour natural gas treatment systems, and so many others.

Adjusting the number of stages in a ring section pump does not affect optimal flow, but allows you to achieve the desired pressure requirements. So for example, let’s say you have a ring section pump with two impellers that produces a flow of 6.3m3 per hour at 100m of head (pressure). When you add another stage, the rated flow (6.3m3/h) stays the same, but the pressure increases to 150m of head. You could add a fourth stage to get 200m of head, a fifth stage to get 250m of head, and so on, until max stages of 12.

Keep in mind that as the liquid’s pressure increases as it passes through each stage, axial thrust begins to occur as a result of the difference in pressure between the suction eye and the back of the impeller. With a difference in pressure across the impellers, axial thrust tries to push the pump shaft toward the suction eyes. This axial thrust must be offset in order for the pump to operate properly, so the rotor must be designed to be hydraulically balanced to preserve bearing life. Inter-stage diffusers (a ring of fixed vanes) minimize radial loads (force that acts at right angles to the shaft), while carefully controlling fluid flow for a more efficient conversion of velocity head into pressure head.