Nagmanflow’s Best Methods to Precise Calibration

We shall now dive into the two most common methods of calibration, the comparison, and the gravimetric method.

1. Comparison Method:
This method involves comparing the flow meter’s output to a reference standard flow meter (Master) and this method is also known as Master meter method.

Materials Required:

• Flow Meter Under Test (FUT).
• Reference Standard: A calibrated reference flow meter or standard with known accuracy.
• Test Fluid: The fluid that the flow meter is designed to measure. Typically, Water.
• Control System: A system to regulate and monitor the flow rate.

Steps to Follow:

• Setup: Install the FUT and the reference standard in the calibration setup.
• Stabilization: Allow the system to stabilize to the operating conditions.
• Comparison Measurements: Simultaneously run the FUT and the reference standard at various flow rates.
• Analysis: Compare the readings obtained from the FUT with the readings from the reference standard.
• Adjustment: If necessary, adjust the FUT settings to match the reference standard readings.
• Reiteration: Repeat the process at different flow rates.
• Documentation: Document the calibration results, including correction factors and deviations.

Advantages of Method:

• Simple and straightforward.
• Suitable for on-site calibration.
• Applicable to a wide range of flow meters.
• Higher throughput

2. Gravimetric Method:

This method involves collecting the fluid over a known period, typically 60s and measuring its mass using high precision weighing scales.

Materials Required:

• Flow Meter Under Test (FUT).
• Accurate Weighing Scale: A precision weighing scale to measure the mass of the collected fluid.
• Control System: A system to maintain a constant flow rate.
• Collection Vessel: A vessel to collect the fluid over a specific period.
• Timer: A timer to accurately measure the collection period.
• Online / Offline Density meter.

Steps to Follow:

• Setup: Install the FUT in the calibration setup with the collection vessel and weighing scale.
• Stabilization: Allow the system to stabilize to the desired operating conditions.
• Calibration Run: Start the flow and collect the fluid in the vessel for a predetermined time.
• Weighing: Weigh the collected fluid using the precision scale.
• Calculation: Calculate the volume of fluid collected using the measured mass and the calculated density by using the formula
• Comparison: Compare the calculated volume with the flow meter’s totalizer output reading.
• Adjustment: If necessary, adjust the flow meter’s settings to match the calculated volume.
• Reiteration: Repeat the process at different flow rates.
• Documentation: Document the calibration results, including correction factors and deviations.

Advantages of Method:

• Highly accurate and precise.
• Less susceptible to environmental influences.
• Ideal for critical applications and laboratory settings.