This paper describes the fabrication of a guarded-hot-plate apparatus suitable for determining the steady-state thermal transmission properties of insulation specimens from 90 K to 900 K in a controlled gas atmosphere from 10-5 kPa to 105 kPa. The long-term goal of the apparatus is to develop thermal insulation reference materials for use over greater temperature and pressure ranges than are currently available. Fabrication and assembly details are presented for the apparatus plates, edge guard, structural support system, thickness measurement system, force application, and vacuum/gas pressurization system. An initial assessment of the uncertainty budget is provided.The apparatus accommodates flat-slab specimens 500 mm in diameter and from 13 mm to 100 mm in thickness. The plate size of 500 mm was selected based on recommendations provided in the current international standard test method for guarded-hot-plate apparatus. The primary components of the apparatus, the hot and cold thermometry plates, were manufactured from commercially pure nickel. The guarded hot plate was fabricated as individual parts to permit the installation of internal heaters and temperature sensors, and was subsequently brazed in vacuum at 1200 K to form a solid metal plate. A thin ceramic coating was applied to the plate surfaces to provide an emittance of 0.8, or greater.
Proceedings Title: 28th (ITCC)| 16th ITES
Conference Dates: June 26-29, 2005
Conference Title: International Thermal Conductivity Conference - International Thermal Expansion Symposium
Pub Type: Conferences
finite element, guarded hot plate apparatus, high temperature, mineral insulated heater, standard platinum resistance thermometry, vacuum