Thermal conductivity sensors measure the thermal conductivity—the ability to conduct heat—of a material. Thermal conductivity (λ) is a physical property measured in watts per meter kelvin (W/m*K). Higher thermal conductivity values such as those of metals indicate materials able to conduct greater amounts of heat, while materials with lower values are effective as thermal insulators.
Thermal conductivity sensors can be used to measure solid, liquid, or gaseous samples and are useful in numerous applications, including soil analysis, material testing, building and construction, and thin film manufacturing. In gaseous media applications they can be used to measure gas concentrations in a binary or quasi-binary gas mixture when the gases within the sample have distinctly different thermal conductivity values.
Two types of sensor: a flat nickel sensor attached to a cable (left) and a needle sensor for soil analysis.
Image credit: HotDisk | Hukseflux