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Design Concepts for a New Guarded Hot Plate Apparatus for Use Over an Extended Temperature Range Pages: 18 Published: Jan 2002
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View License Agreement Source: STP1426-EB Abstract The National Institute of Standards and Technology is building a new guarded hot plate apparatus (GHP) for use at temperatures from 90 to 900 K, with provision to conduct tests in various gases at controlled pressures from 0.013 Pa to 0.105 MPa ( 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 closefitting 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 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.
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