Automated high-temperature guarded-hot-plate apparatus for measuring apparent thermal conductivity

Technical Report · Sun May 01 00:00:00 EDT 1988

OSTI ID:6807538

Hust, J G; Filla, B J; Hurley, J A; Smith, D R

An automated guarded-hot-plate apparatus was designed and built to meet the requirements of ASTM Standard Test Method C-177 for measuring the thermal conductance of thermal insulation. Apparent thermal conductivity was measured with this apparatus in the range from 40 to 100 mW/(m.K) at mean temperatures from 300 to 750 K, in environments of air and helium, at pressures ranging from atmospheric pressure to roughing-pump vacuum. The apparatus is controlled by a desk-top computer. A thermocouple device of novel design more accurately senses the average temperature over the surface of each heater plate. An improved algorithm for the control sequence leads to more-stable heater powers and specimen temperatures. Overall uncertainties of apparent thermal conductivities at atmospheric pressure are 2% at 300 K and 5% at 750 K when measuring conductivities in the range from 40 to 100 mW/(m.K). The apparatus will be valuable in development of new Standard Reference Materials of low conductivity and for higher-temperature ranges, and is being used in comparative interlaboratory measurement programs.

• Research Organization: National Bureau of Standards, Boulder, CO (USA). Chemical Engineering Science Div.
• OSTI ID: 6807538
• Report Number(s): PB-88-242060/XAB; NBSIR-88/3089
• Country of Publication: United States
• Language: English

Related Subjects

420201 -- Engineering-- Cryogenic Equipment & Devices
440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CALIBRATION STANDARDS
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
STANDARDS
TEMPERATURE MEASUREMENT
THERMAL CONDUCTIVITY
THERMAL INSULATION
THERMOCOUPLES
THERMODYNAMIC PROPERTIES