Engineering selection guide

How to Choose an Electric Multistage Pump

Select an electric multistage pump by the required flow and pressure at the same operating point. Then verify suction conditions, motor supply, materials and the exact model curve before choosing a stage count or motor size.

Multistage pump ranges and parameters →

A practical selection sequence

1. Define normal, minimum and peak flow

List the flow required by the process in m³/h for each important operating mode. A pressure booster, reverse-osmosis feed and boiler-feed service may have different duty profiles. If several outlets open and close, provide the simultaneous demand rather than adding every theoretical maximum.

2. Calculate head at each duty point

Total dynamic head combines elevation change, required discharge pressure, suction pressure and friction losses through pipework, valves and equipment at the chosen flow. About 10 m of water head corresponds to 1 bar of pressure for water, but actual head must account for suction conditions and liquid density. State both flow and head together.

3. Compare electric multistage arrangements

Vertical CDL/CDLF-style pumps suit compact booster and treatment skids; horizontal or heavier-duty multistage ranges may better fit different flows, mounting or pressure requirements. Stage count adds head, but it is not a substitute for reviewing the complete model curve and allowable pressure. Check whether 50 Hz or 60 Hz operation changes the selected duty point.

4. Check suction and liquid compatibility

Give the minimum suction pressure, water level, liquid temperature and altitude. Compare available NPSH with the pump's required NPSH using an engineering margin; insufficient suction conditions can cause cavitation. Specify liquid chemistry, solids, chloride content and required wetted materials and seals.

5. Size the motor and controls

Read shaft or input power at the proposed operating point from the curve and confirm the motor rating, voltage, phase and frequency. A variable-frequency drive can help varying-demand systems, but minimum speed, cooling, pressure control and approved operating range still need confirmation. Do not choose motor kW solely from the hydraulic power calculation.

6. Verify final selection and service access

Request the current exact-model performance curve, efficiency and power data, NPSH requirement, dimensions, seal specification and allowable operating range. Include pipe connection, installation orientation, control-panel requirements and maintenance clearance in the purchase specification.

Worked starting point: electric pressure booster

Suppose a process requires 12 m³/h at 55 m TDH (approximately 53 US gpm at 180 ft). At 12 m³/h (0.00333 m³/s), the water hydraulic power is about 1.8 kW using ρgQH. Actual electrical input is higher because pump and motor efficiencies are below 100%. Select the motor and stage configuration only after checking the exact curve at 12 m³/h and 55 m, suction NPSH and the available electrical supply. This is an illustration, not a model recommendation.

Frequently asked questions

Does more stages always mean a better pump?

No. More stages can add head, but the correct selection is the model whose curve covers your flow and head efficiently within its pressure and power limits.

Can I use maximum head as my required duty head?

No. Maximum head is commonly near zero flow. Specify the head required at your actual flow and use the model curve to verify both together.

When is a variable-frequency drive useful?

It may help when demand and pressure requirements vary, provided the pump, motor and controls are approved for the intended speed and operating range.

Engineering background

These references explain general pump-selection principles; they do not certify a JIABO product or replace its current datasheet.

Confirm all final selections against the exact model’s latest performance curve, material specification and installation instructions.