Technical Publication Advances in Thermal Dispersion Mass Flow Meter Accuracy By Dan McQueen, President Fluid Components International (FCI) Visit FCI on the Worldwide Web g www.fluidcomponents.com Headquarters g 1755 La Costa Meadows Drive San Marcos, California 92078 USA Phone 760-744-6950* g Toll Free 800-854-1993 g Fax 760-736-6250* European Office g Persephonestraat 3-01 5047 TT Tilburg, The Netherlands Phone 31-13-5159989 g Fax 31-13-5799036 FCI is ISO 9001:2000 and AS9100 certified * Please note FCI area code changes from “760” to “442” effective January 1, 2009

Advances in Thermal Sensing Designs Thermal flow measuring technology has come a long way since the introduction of thermocouple technology and early hot wire anemometers. Thermal technologies depend on heat transfer and traditionally operate on differential temperature measurements between two temperature sensitive materials to generate a signal directly proportional to the temperature differential and mass flow rate. Over the years, Thermal type flow sensors have been utilized across a very wide spectrum of applications and feature an assortment of performance limits. Modern Thermal flow sensor...

in current generation FCI Thermal mass flow meters. Error and uncertainty reduction have undergone nearly an order of magnitude improvement in recent years, which has enabled calibrations at 0.5% of reading and below across 100:1 turndowns. Calibration Methodologies and NIST Traceable Facilities Close The Gap The advances in sensing and signal processing necessitated improvements in calibration routines and methodologies. In order to bring the pedigree of Thermal type flow instruments truly into the high performance category and match the real field conditions of users, manufacturers needed to...

conditioners, which provide excellent isolation, swirl reduction and at virtually no pressure loss. This type of flow conditioning has dramatically opened the application universe for point sensing technologies, such as Thermal, whose normal installation guidelines recommend pipe runs of 20 diameters upstream straight run and 10 pipe diameters of downstream run. By combining and embedding flow conditioners with thermal mass flow meters they attain their published performance specifications in installations with less than 7 total pipe diameters. Process Condition Effects and Multi-Variable Sensing...