Design Concepts for a New Guarded Hot Plate Apparatus for Use Over an Extended Temperature Range.
Design Concepts for a New Guarded Hot Plate Apparatus
for Use Over an Extended Temperature Range.
(327 K)
Flynn, D. R.; Zarr, R. R.; Hahn, M. H.; Healy, W. M.
Insulation Materials: Testing and Applications, 4th
Volume. ASTM STP 1426. 2002, ASTM International, West
Conshohocken, PA, Desjarlais, A. O.; Zarr, R. R.,
Editor(s)(s), 98-115 pp, 2002.
Keywords:
insulation; heat transmission; conductive heat transfer;
heat transfer; thermal conductivity; thermal insulation;
thermal resistance
Abstract:
The National Institute of Standards and Technology is
building a new guarded hot plate apparatus (GHP) for use
at temperatures from 90 K to 900 K, with provision to
conduct tests in various gases at controlled pressures
from 0.013 Pa to 0.105 MPa ({approximately equal to}
1.04 atm). Important features of the design of the new
NIST GHP include: enclosure of the entire apparatus in a
vacuum chamber; solid metal hot plates and cold surface
plates to provide highly isothermal surfaces in contact
with the test specimens; an integral close-fitting edge
guard to minimize the effects of edge heat losses or
gains; connection guard blocks to minimize the effects
of heat conduction along coolant lines, heater leads,
thermometry wells, and sensor leads coming from the hot
plate and the cold plates; provision of a system to
provide a known clamping force between the specimens and
the contacting hot and cold plate surfaces; provision of
an accurate system for in-situ measurement of specimen
thickness during a test and the use of three long-stem
standard platinum resistance thermometers to measure the
average temperature of the meter plate and the two cold
plates.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899