Transient Plane Source (TPS)
Simultaneous determination of thermal properties with Transient Plane Source. Thermal properties of material, components and elements in many industrial applications are of vital importance in their final functionality. Thermal properties (thermal conductivity, thermal diffusivity and specific heat capacity) varies by temperature and moisture thus, for an accurate measuring of these properties needs laboratory-based devices design for specific property ranges and material. Transient Plane Source (TPS) technique is a device that can be used both in laboratory and in-situ measurements of all three related properties form cryogenic to high temperature (1000 K). It can measure thermal conductivities between 0.01 and 500 W/mK.
The TPS method involves the use of a very thin double metal spiral, 10 mm thickness, sandwiched
between two layers of Kapton (25 mm thickness), in close contact with the material to be investigated. The double metal spiral serves both as the heat source and as a resistance thermometer. When making measurements in solid bodies, the spiral is clamped between two surfaces of the same material, as shown in the Figure 1. The radius of the sensor can very between 2 mm and 30 mm thus, the sample size can vary between 8 mm and 120 mm or larger.
Figure 1 a) TPS sensor on the first sample of the material under investigation, b) TPS sensor is clamped between two samples of the material.
TPS applications
- Standard: Measuring thermal properties of solids (metals, ceramics, polymers etc), liquids, paste and powders.
- Anisotropic: Thermal properties of an anisotropic material can be determined if the specific heat capacity is known.
- Specific heat capacity: Determination of specific heat capacity of anisotropic material.
- Slab: Determination of thermal conductivity of thin and high conductive material e.g. Aluminium. Thickness range of the samples is from 1 mm to 3 mm.
- Thin film: Determination of thermal conductivity of thin film e.g. textile, plastic foil, Aluminium foil and paper. Thickness range of the samples 25mm to 500mm.
- Single sided: In this application the TPS sensor is attached to a material with know thermal conductivity and placed on the sample (surface) under investigation. This application can be used in field measurements.