Probe types Mini half-space probe, half-space probe, full-space probe, field probe Different probe types are available for TK04 for use with the same instrument. All probes consist of a heating device and a temperature sensor embedded in a metal tube, called source. The dimensions of the source depend on the intended use, with the half-space probes it is embedded in the underside of a poorly conducting probe body. For a list of all available probe types see the technical specification. All probes have a rugged design, are protected against moisture and come pre-calibrated and completely maintenance-free. The user is not required to perform calibration tests, but a suitable reference standard is included in the delivery for occasionally checking instrument and probes.

Sample materials and sizes Some sample materials TK04 is designed for testing solids (like soil samples, rocks, plastics, glass, ceramics, building materials, wood, or foodstuffs), powder, fragments, viscous liquids and for in-situ tests in the measuring range of 0.1 to 10 W/mK. Minimum sample size depends on the dimensions of the chosen probe and on the properties of the sample material. As a rule of thumb, the higher the thermal conductivity of the material, the larger the required sample size. There is no upper size limit, and no requirements regarding the shape of the samples. For the minimum size see the probe specifications and the sample preparation notes).

Choice of a suitable probe Except for very few restrictions, all probe types can be used for all materials. In most cases, the probe can be chosen matching shape and size of the available sample pieces or depending on the necessary sample preparation: the standard full-space probe requires a drill hole of 70 mm in length and 2 mm in diameter (if the sample material is soft enough, the probe can be inserted without pre-drilling), the standard half-space probe requires a plain and smooth surface approx. 80 mm in diameter. The mini half-space probe is intended for small samples from 50 mm in diameter, for in-situ tests a special full-space probe with a length of 300 mm is available.

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