Centrifugal pumps: A centrifugal pump uses a rotating impeller to add energy to a fluid and move it through a system.
How it works
Fluid enters the pump at the centre of the impeller. As the impeller spins, it throws the fluid outwards into the casing, which converts speed into pressure and guides the fluid to the discharge.
The flow a pump delivers depends on the system it works in. Where the pump curve meets the system curve is the operating point, and it should sit near the pump’s best efficiency range.
Types
Common groupings are end-suction, split-case, multistage and vertical pumps. Pumps can also be grouped by how the shaft is sealed, such as mechanical seal or sealless designs, and by the materials used for wetted parts.
Key specifications
| Parameter | What it affects | Value or range | Source and conditions |
|---|---|---|---|
| Flow rate (m³/h) | Sets how much fluid the pump moves at the duty point | Demo range: 5 to 500 | Demo data, not from a datasheet |
| Head (m) | Sets the pressure the pump can add at a given flow | Demo range: 10 to 120 | Demo data, not from a datasheet |
| Motor power (kW) | Sets the drive size and running cost | Demo range: 1.5 to 90 | Demo data, not from a datasheet |
| Efficiency at best point (%) | Affects energy use over the life of the pump | Demo range: 55 to 80 | Demo data, not from a datasheet |
| Materials of construction (type) | Sets compatibility with the fluid and its temperature | Cast iron or stainless steel (demo) | Demo data, not from a datasheet |
Selection criteria
- Duty point: the flow and head needed, and how they vary
- Fluid: viscosity, solids content, temperature and corrosiveness
- Suction conditions: available head against the pump’s requirement
- Materials and shaft sealing for the fluid
- Energy use across the real operating profile
- Access for maintenance and availability of spares
Sources and review
- References
- Demo reference: manufacturer datasheet (placeholder) (checked 2026-11-07)
- Demo reference: relevant standard (placeholder) (checked 2026-11-07)
- Last reviewed
- Not yet reviewed
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FAQ
How do I read a pump curve?
A pump curve plots head against flow for a given speed and impeller size. Read the head at your required flow, then check the efficiency and the power at that point.
What is NPSH and why does it matter?
Net positive suction head is the margin that keeps the fluid from vaporising at the impeller inlet. If the margin available at the installation is lower than the pump requires, the pump can cavitate, which causes noise and damage.
When should I consider a positive displacement pump instead?
Positive displacement pumps often suit high-viscosity fluids or applications that need near-constant flow against changing pressure. Compare both types on the same operating conditions.
What should I ask a supplier before I decide?
Ask which model and revision the figures describe, the conditions they were measured under, which standards apply and for what scope, and what local support and spares are available.