Probe for measuring melt thermal conductivity and diffusivity - using a sheathed linear heating probe with a central sensor

摘要

An instrument for measuring the thermal conductivity and thermal diffusivity of a material, esp. polymers under press., is based on use of a linear temp. sensitive probe traversing a sample chamber coaxially. The ratio of the min. internal cross-section dimension of the chamber; max. external cross-section of the probe is 25:1-100:1. The press. on the material in the chamber can be increased by an ancillary thrust device. Used for simultaneous determination of thermal conductivity and diffusivity under dynamic thermal flux by dissipating a heating current via the probe traversing the chamber. Results are obtd. from classic time/temp. plots as detected by the central sensor in the probe. It is suitable for measurements at typical polymer processing press. and temps. and avoids end effect errors of the order of 10% associated with use of cantilever probes. It is also more robust than use of thin plain resistance wire heater/probes.