Measurements of Temperature and H2O Mole Fraction in a Glass Furnace Using Diode Laser Absorption

Temperature and H₂O mole fractions have been measured nonintrusively in a float glass furnace using a newly developed tunable diode laser sensor system: the MetroLaser LTS-100. The technique utilizes a single near-infrared laser to measure H₂O absorption lines that are inactive at room temperature, therefore the measurement does not suffer from interference from ambient H₂O, resulting in an instrument that can be placed a safe distance from the furnace being measured. Results are presented of measurements at a rate of 5 Hz during four hours of operation, revealing details of the firing and exhausting cycles of the furnace. The measured temperatures had a precision of 11 K rms and an estimated accuracy of 50 K. These results represent a capability that is not available with conventional sensors, and may lead to improved methods of furnace operation and control