Active millimeter-wave pyrometer

Journal Article · Sat Apr 01 04:00:00 EST 1995 · Bulletin of the American Physical Society

DOI:https://doi.org/10.1063/1.1145376· OSTI ID:375032

Woskov, P P ^[1]

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1. Massachusettes Institute of Technology, Cambridge, MA (United States)

There is a continuing need for reliable and accurate temperature measurements inside hot and dirty environments. Many processes encompassing manufacturing, waste remediation, and power production make use of high temperature furnaces where currently available temperature measurement instrumentation is not always adequate. Thermocouples require direct surface contact and are limited to temperatures < 1700{degrees}C. Infrared pyrometers require clear, direct lines of sight that are frequently unavailable or become obscured during operations. Furthermore the surface emissivity, which can vary during the process, must be known. Millimeter-wave pyrometry overcomes all these limitations. A 135 GHz heterodyne receiver with a rotatable graphite waveguide/mirror system has been implemented on a waste remediation DC arc furnace for internal surface temperature measurements. The linear temperature measurement range extends from <1{degrees} to approximately 15,000{degrees}C relative to ambient with a simultaneous capability to monitor surface reflectivity with the local oscillator leakage. Reliable and robust operation on a continuous 24 hour basis in a smoky, dirty furnace environment is demonstrated for more than 5 furnace runs reaching a maximum temperature of 2200{degrees}C. Complete temperature profile measurements with approximately 5 cm spatial resolution clearly documented thermal gradients on the slag melt surface and refractory walls and ceiling for all operating regimes of the furnace. The unique active probing capability of this instrument provided additional real time information on melt surface turbulence, changing furnace wall emissivity, and millimeter-wave optic losses inside the furnace.

• Sponsoring Organization: USDOE
• OSTI ID: 375032
• Report Number(s): CONF-9304297--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
FURNACES
MICROWAVE RADIATION
OPERATION
PERFORMANCE TESTING
PYROMETERS
TEMPERATURE MEASUREMENT