Turbine Meter vs Positive Displacement
Side by side comparison: how they work, where each fits, and which to choose.
Quick answer: Turbine meters suit clean, low viscosity fluids at high flows; positive displacement meters suit viscous liquids and low flows with high accuracy and no straight run.
Turbine Meter vs Positive Displacement: Comparison Table
| Aspect | Turbine Meter | Positive Displacement |
|---|---|---|
| Principle | Rotor speed proportional to velocity | Traps and counts fixed volumes |
| Viscosity | Best at low viscosity | Accuracy improves with viscosity |
| Straight run | Needed, plus conditioner | Not needed |
| Pressure loss | Low to moderate | Higher |
| Solids | Bearings wear | Can jam; strainer needed |
| Output | Pulses (K factor) | Pulses (K factor) |
Choose Turbine Meter when
- Clean fuels, water and gases at high flow
Choose Positive Displacement when
- Oils, syrups, resins and dosing
- Low flows and fuel dispensing
Key Differences Explained
Both are mechanical meters with moving parts and pulse outputs. Turbines lose accuracy as viscosity rises; PD meters slip less as viscosity rises.
Both are widely used for custody transfer, proved with meter factors.
Related Glossary Terms
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Frequently Asked Questions
What is the difference between Turbine Meter and Positive Displacement?
Turbine meters suit clean, low viscosity fluids at high flows; positive displacement meters suit viscous liquids and low flows with high accuracy and no straight run.
Why do turbine meters need a strainer?
Particles damage bearings and blades.
Is an oval gear meter a PD meter?
Yes, as are piston, nutating disc and rotary vane meters.
How is accuracy maintained?
By proving and applying a meter factor.
Learn more on the blog
Types of flow meters
A practical guide on instrumentationblog.in that goes deeper into this topic with field examples.
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