Calibration is the process of comparing the measured output of a device with a reference value and setting it accordingly to receive perfect readings.
Flow meter calibration can be done by a professional or by the end-user themselves if they have the right equipment.
Another common term for returning a purchased flowmeter to the factory for rechecking is re-calibration.
In principle, calibration doesn’t need adjustments, but practically it is done quite regularly.
Why is calibration necessary?
The purpose of a flowmeter is to measure the flow rate of gas or fluid passing through it.
Professionals use it to get accurate flow measurements for various applications where it is crucial to maintain the flow rate at set values, like in petroleum industries, beverage industries etc.
Regular flow meter calibrations ensure that your measurements are accurate as per the mentioned specifications.
Now, getting regular calibrations does not mean a faulty equipment. Every instrument will degrade over time because of wear and tear and require maintenance for proper functioning.
Flow meters may get affected or damaged by the accumulation of dirt or corrosion. They can also get hurt because of impact, variations in the process or improper installation.
Best procedures for calibrating flow metres
All the standard calibration practices apply to flow meter calibrations; there are also some specific practices that you can keep in mind for accurate calibration.
Below are some practices you can follow for flow meter calibrations:
The standard you use for calibration must be accurate enough to perform the calibration.
The general thumb rule is that the standard should be at least four times more accurate than the device undergoing the test (DUT); however, this may vary depending on the needs of the calibration.
The standard used should be from a recognized standard
Traceability provides an unbroken documentation chain showing how the measurements compared to even more objective standards.
Traceable measurements help to prove that the measurements are what your flowmeter says they are, within the specific ranges.
- The rate of flow between the testing device and the standard should be regulated
Since the standard and the DUT flow rates are compared in real time, the system flow rate should not remain consistent.
The flowmeter must also measure all measurements made by the calibration standardsimultaneously
This means you must be careful about leaks or sudden temperature changes, as they might affect the final result.
The calibration should be performed under typical conditions required for the actual operation.
For instance, the viscosity or heat content of the medium that is being measured can affect the flowmeter. It is essential to match the calibration with the actual application for the best results.
It is very necessary to follow the proper practices of flow meter calibration, as wrong measurements can lead to hazardous situations.