Sierra Quadra SeriesSierra Instruments' new QuadraTherm 640i/780i Thermal Mass Flowmeter Series marks a breakthrough in thermal dispersion technology. With its sensor design advancements, coupled with a proprietary iTherm “Brain”, the 780i inline version achieves gas mass flowrate measurement accuracy of +/- 0.5 percent of reading above 50 percent of the full scale (Air) making it the most accurate thermal meter in the industry, according to Sierra. At the heart of the flowmeter is its patented QuadraTherm sensor and proprietary iTherm algorithm set. Unlike traditional thermal sensors, QuadraTherm introduces four sensors—three precision platinum temperature sensors and one patented no-drift DrySense mass velocity sensor, which is designed to improve accuracy and long-term stability. The QuadraTherm sensor isolates forced convection (the critical variable for measuring gas mass flowrate) by calculating and then eliminating unwanted heat-transfer components, like sensor stem conduction, one of the major causes of false flow readings. The QuadraTherm flowmeter is available in two models: the 640i insertion and 780i inline. The QuadraTherm family has a no-drift sensor with lifetime warranty; has multivariable output—mass flow, temperature, pressure (optional); measures all inert and all non-condensing clean gases; flammable gases (methane, propane, hydrogen, and digester gas); repeatability for mass flowrate is +/- 0.15 percent; has ValidCal Diagnostics to validate calibration in the field; and its gas accuracy is +/- 1 C (1.8 F). –