Our Guide to Flowmeter Calibration Techniques

At JLC International, we sell a wide variety of control and measurement instruments including dew point meters, flowmeters, and other devices. As such, we understand the importance of having your technology set up in such a way that they are functioning accurately. The most common way to make sure your flow meter is working effectively is via calibration.

Calibrating flowmeters can be done using various methods and techniques. Each method has advantages and disadvantages, but choosing the correct one depends upon the desired outcome of the calibration as well as the size of the flowmeter you are adjusting.

In this blog, we’ll break down the most common flowmeter calibration techniques and offer insight into the applications of each methodology.

Bucket and Stopwatch Method

The bucket and stopwatch method is the most primitive of flowmeter calibration techniques (as it is possible for inaccuracies to occur during testing), but it is commonly chosen for its ease of use and convenient viability. It is ideal for:

  • Quick checks and calibrations
  • Lower flows

Do not use this method if your flow meter has an extremely low flow (for less stable liquids).

For proper calibration and reduced errors, we suggest metering a large volume over a long period. An ideal test would last for at least two minutes and should use scales that have a 0.1 kg resolution. This resolution will minimize measurement errors. Time measurement errors will also be reduced, giving a maximum inaccuracy of ±1.1% during a two-minute test.

Flying Start & Stop Method

The flying start and stop method is the younger, more advanced brother of the bucket and stopwatch method. This approach utilizes a counter system, electronic clock, and a custom diverter, all of which are connected. Liquid is deposited via the flowmeter from one side of the system to the other, split via a diversion device or diverter valve.

In this method, the faster the diversion, the more accurate the calibration of your device will be.

Volumetric Measurement Technique

The volumetric measurement technique is a quick test that you can do to compare the records on your flowmeter versus what is measured in your volumetric measurement vessel. These vessels are generally calibrated at specific temperatures and can be tested using temperature coefficients for reference point variations.

Piston Provers Method

The piston provers method is straightforward and easy for many people to do when calibrating their flowmeter. Simply, all a user needs to know is the diameter of the piston, and their encoder will deliver them results via pulses for each liter of liquid that passes through the piston. Users can make adjustments for temperature and pressure as well.

Pipe & Ball Provers Method

For large-diameter pipes as well as situations where high accuracy is essential, pipe and ball provers are one of the best calibration techniques. These uni- or bi-directional calibration systems use a method that stems from the displacement of a ball within a piston prover. These systems generally deliver readings with ±0.05% accuracy.

Transfer Standards

Utilizing a transfer standard for calibration of your flowmeter is simple. For the highest accuracy, the flowmeter must be used under the same conditions in which it was calibrated.

Our Measurement Technology

JLC International is a trusted distributor for high-quality measurement instrumentation including Shaw dew point meters, ultrasonic flowmeters, and more. For information on any of our products, call +1-888-358-2518.