A centrifugal pump moves fluid by converting rotational energy (from a motor) into kinetic energy (fluid motion) and then into pressure energy to push the liquid through a system. Here’s how it operates:
Before diving into operation, let’s review the main parts:
Impeller: Rotating blades that accelerate the fluid.
Casing (Volute): Spiral-shaped housing that converts kinetic energy into pressure.
Shaft: Connects the motor to the impeller.
Suction & Discharge Ports: Where fluid enters/exits.
Seals/Bearings: Prevent leaks and support rotation.
Why? Centrifugal pumps cannot move air (they need liquid to create suction).
How? The pump casing must be filled with liquid before startup (unless self-priming).
An electric motor (or engine) spins the shaft and impeller at high speed (typically 500–5000 RPM).
The rotating impeller flings fluid outward due to centrifugal force, increasing its velocity.
This creates a low-pressure zone at the impeller’s center (eye), pulling in more fluid.
The fast-moving fluid enters the spiral-shaped volute casing.
As the volute expands, the fluid slows down, converting kinetic energy → pressure energy.
High-pressure fluid exits through the discharge nozzle.
The cycle repeats as long as the pump runs, maintaining steady flow.
Faster impeller speed = higher flow & pressure.
The Bernoulli principle explains how velocity converts to pressure in the volute.
NPSH Required (NPSHₐ): Minimum pressure needed to prevent cavitation (bubbles forming and collapsing, damaging the impeller).
NPSH Available (NPSHᵣ): Must be > NPSHₐ for safe operation.
Shows how flow rate (Q), head (H), and efficiency (η) relate.
Best Efficiency Point (BEP): Ideal operating zone.
| Issue | Cause | Fix |
|---|---|---|
| No Flow | Not primed, clogged suction | Prime pump, check strainer |
| Low Pressure | Worn impeller, wrong speed | Replace impeller, adjust RPM |
| Cavitation | Low suction pressure | Increase NPSHₐ (lower pump, bigger pipe) |
| Overheating | Running dry or at low flow | Ensure proper liquid supply |
| Feature | Centrifugal Pump | Positive Displacement Pump |
|---|---|---|
| Flow Type | Smooth, variable | Pulsating, fixed per cycle |
| Viscosity Handling | Best for thin fluids (water, oil) | Handles thick fluids (honey, sludge) |
| Efficiency | High at BEP, drops off | More consistent |
| Self-Priming? | Usually no | Often yes |
A centrifugal pump works by spinning an impeller to create centrifugal force, accelerating fluid and converting speed into pressure via the volute casing.
It’s ideal for high-flow, low-viscosity applications (water, chemicals, fuel).
Proper priming, NPSH, and BEP operation are critical for efficiency and longevity.
Need help troubleshooting a pump issue? Ask for details!
The above content is compiled and published by Zhilong Drum Pump supplier, please specify, to buy oil drum pump, electric drum pump, high viscosity electric drum pump, fuel drum pump, food grade drum pump and so on, please contact us.