Application note A092-GP99

Calibration setup for mass flow devices

How do you know for sure that the gas flow that you measure or set is the right one? The answer is quite simple: make sure that the device with which you measure or set the gas flow gives the real value - and that can be done by calibrating (and adjusting) the device.

Calibration is the process of finding the deviation between a unknown quantity (device under test, DUT), and a known (reference) quantity. Results of a calibration are stored in a calibration certificate.

In this particular case,  Bronkhorst has developed a mobile calibration setup for a customer in the chemical industry who uses a lot of mass flow meters and controllers. This customer was interested in in-house calibration equipment for his flow devices, because it would reduce the downtime of his installation and he would be more flexible in choosing the moment for this performance check. 


Application requirements

In order to calibrate mass flow devices on site by a client, they need to have a calibration setup with a set of already calibrated reference mass flow devices with the right flow capacity. In this particular setup the customer preferred an open, mechanical and compact design without any electronic control or power adapters.

Important topics

  • Accurate calibration of large series
  • Fast, time-saving calibration

Process solution

This particular setup consists of an entrance point where the pressurised gas enters, followed by a manual shut-off valve and a filter to prevent dust or other particles from passing. Next is a pressure controller to set and read out the correct pressure. Then we have a thermometer followed by the mass flow device under investigation, which can be a mass flow meter or controller. Finally, the setup consists of two reference mass flow meters in parallel. In this case one for small gas flows up to 20 ln/min (EL-FLOW Prestige or EL-FLOW Select series) of air and one for large gas flows up to 1200 ln/min (EL-FLOW Select series) of air, that have been calibrated to national standards.

This setup is a way to test whether the mass flow device is suitable and good enough in terms of accuracy and function. When the deviation between the test device and the reference device is within the permissible tolerance, no further action is required. When the deviation is outside the permissible tolerance, it is recommended that you send the mass flow meter to Bronkhorst in order to have the deviation corrected.

Bronkhorst can train the users of calibration setups and adjustments at its training centre or even on-site (on request).
In order to check the performance of the reference mass flow meters, we recommend to send them at regular intervals – every year - to Bronkhorst for calibration and adjustment.

In addition to companies that use many mass flow devices, a similar mobile calibration setup can be of interest for (governmental) institutes and companies in many different industries, that need to be sure to have highly accurate mass flow devices at all times. If the calibration intervals are to be short or for companies that have to carry out many projects under time pressure, a mobile calibration setup can be a good solution. Bronkhorst can offer you a calibration setup which will be tailored to your needs.

We have learned that about 90% of the calibration setups are used for calibration only. Adjustment however, is also possible using our FLUICAL software. FLUICAL is a free software developed by Bronkhorst.

Learn more about the Bronkhorst Calibration Centre (BCC) or our FLUICAL calibration software.

Flow scheme
Flow scheme