Sierra Instruments QuadraTherm 640i/780i thermal mass flow meter series

Sierra Instruments has introduced the QuadraTherm 640i/780i thermal mass flow meter series. With its sensor design advancements, coupled with a proprietary iTherm algorithm, the 780i inline version achieves gas mass flow rate measurement accuracy of ±0.5% of reading above 50% of the full scale (air).

Traditional thermal sensors have two sensors - one temperature sensor and one velocity sensor, each in a separate probe. QuadraTherm introduces four sensors - three precision platinum temperature sensors and one no-drift DrySense mass velocity sensor, which uses a proprietary manufacturing process to improve accuracy and long-term stability.

The QuadraTherm sensor isolates forced convection (the critical variable for measuring gas mass flow rate) by calculating and then eliminating unwanted heat-transfer components like sensor stem conduction, one of the major causes of false flow readings. The result is a fundamentally different gas mass flow rate calculation using all pertinent variables for a precise, stable and accurate thermal mass flow measurement.

The product is available in two models: the 640i insertion and 780i inline. The range has a no-drift sensor and a multivariable output for mass flow, temperature and pressure (optional). It measures all inert and all non-condensing clean gases as well as flammable gases (methane, propane, hydrogen, and digester gas). Repeatability for mass flow rate is ±0.15% and gas accuracy is ±1°C.