Bronkhorst USA Inc. is proud to announce the availability of the new EL-FLOW® Prestige.

EL-FLOW® Prestige is the next generation of Bronkhorst Mass Flow Meters/Controllers for gases. Nearly all core components have been redesigned and many improvements and innovations have been incorporated.

The accuracy (really inaccuracy) of mass flow instruments is specified in one of two ways, either accuracy as a percentage of full scale (% FS), or accuracy as a percentage of reading (% RD).

If an instrument has accuracy specified as % FS then the error will have a fixed value no matter where the flow is in the flow range. Take, for example, an instrument calibrated for a flow of 100 ln/min with stated accuracy 1.0% of FS. At a flow of 100 ln/min (full scale) the error will be 1% of full scale, or +/- 1 ln/min. As the flow moves way from full scale the error will still be 1% FS (+/- 1 ln/min), so at a flow of 50 ln/min that error of +/- 1 ln/min becomes a larger percentage (+/- 2%) of flow. Going further away from full scale flow further increases the error as a percentage of flow; at a flow of 10 ln/min the +/- 1 ln/min error is +/- 10% of the flow.

If, however, an instrument has accuracy specified as % RD then the error will always be the same percentage of the actual flow. Using the 100 ln/min instrument again as the example, but this time with a stated accuracy of 1% RD, at 10 ln/min of flow the error is only +/- 1% of the flow, better by 10 times.