1. What is the working principle of a Coriolis mass flow meter?
Answer:
It works on the Coriolis Effect, where a vibrating tube carrying fluid experiences a phase shift or twist proportional to the mass flow rate. The fluid’s inertia causes this deflection.
2. What type of flow does a Coriolis meter measure directly?
Answer:
It measures mass flow rate directly. Volume flow, density, and temperature can be derived.
3. What are the main components of a Coriolis flow meter?
Answer:
-
Vibrating flow tubes
-
Electromagnetic or piezoelectric drive coil
-
Pick-up sensors
-
Transmitter
4. Can a Coriolis meter measure density? How?
Answer:
Yes. The natural frequency of the vibrating tube changes with the fluid’s density. The transmitter calculates density from this frequency.
5. What kind of fluids can be measured using a Coriolis meter?
Answer:
It can measure liquids, slurries, and gases, including viscous and non-Newtonian fluids.
6. What are the advantages of Coriolis meters?
Answer:
-
Direct mass flow measurement
-
High accuracy (±0.1% or better)
-
Measures density and temperature
-
No need for straight pipe runs
-
Bidirectional flow measurement
7. What are the limitations of Coriolis meters?
Answer:
-
Expensive
-
Pressure drop is higher than other meters
-
Performance affected by vibration and air entrainment
-
Limited for very large pipe sizes
8. What is zero-point stability in Coriolis meters?
Answer:
It’s the ability to maintain zero output when there is no flow. Critical for measuring low flows accurately.
9. Can Coriolis meters be used for custody transfer applications?
Answer:
Yes, they are approved for custody transfer due to their high accuracy and repeatability.
10. What is the typical accuracy of a Coriolis meter?
Answer:
±0.1% to ±0.2% of the reading, depending on the model and application.
11. How do temperature variations affect Coriolis meters?
Answer:
Temperature changes affect tube stiffness, altering vibration frequency. Modern meters compensate using built-in temperature sensors.
12. What is the Coriolis effect in simple terms?
Answer:
It’s the apparent deflection of moving fluid in a rotating or vibrating frame—in this case, causing a twist in the vibrating tube when fluid flows through it.
13. How do Coriolis meters handle multiphase flow or entrained gas?
Answer:
Performance may degrade. Entrained gas can dampen vibrations, causing errors. Advanced diagnostics can detect and mitigate this.
14. Do Coriolis meters require upstream/downstream straight runs?
Answer:
No, they are not sensitive to flow profile and can be installed in tight spaces.
15. What maintenance is required for Coriolis meters?
Answer:
Minimal. Routine checks on zero calibration, diagnostics, and sensor health via the transmitter are recommended.
16. Can you use a Coriolis meter for batching applications?
Answer:
Yes, especially where precise mass delivery is needed. Fast response time makes them ideal for batch control.
17. How is the Coriolis meter calibrated?
Answer:
Factory calibrated using traceable mass flow standards. Field zeroing may be needed but full calibration rarely required onsite.
18. Can Coriolis meters be installed vertically or horizontally?
Answer:
Yes. But orientation affects draining and gas entrainment, so manufacturer recommendations should be followed.
19. What is the role of the transmitter in a Coriolis meter system?
Answer:
Processes sensor signals to calculate mass flow, density, temperature, and provide outputs (4-20mA, HART, etc.)
20. What diagnostics features are available in modern Coriolis meters?
Answer:
-
Tube fatigue monitoring
-
Entrained gas detection
-
Vibration diagnostics
-
Smart alerts for cleaning, calibration, or faults