A constant heat pulse is generated inside the specimen and the following temperature response is measured. 
The heat pulse is produced due to Joule heating from the electrical resistance of the hot ball sensor. 
The thermometer measures the temperature response to the heat pulse.

    Measurement scheme


Real experimental set-up with  RTM monitoring system


Hot ball sensor


Two configurations of hot ball fixing can be used when RTM is working in monitoring regime, namely surface and hole configurations.

surface configuration

hole configuration


Portable system RTP and itís application

An instrument RTP was constructed to realize the measurements, to calculate the required parameters and to store the corresponding data. The instrument consists of the hot ball sensor and the electronic unit that realizes the required functionalities to obtain data on thermal conductivity and the data logger. The measurements are performed in the measuring cycles. A cycle consists of measuring a ball temperature (base line), generation of a constant heat in the ball, measuring the temperature response of the ball (see plot below). The heat generation is interrupted after some time when the temperature is stabilized. Then a period of the temperature equilibration follows.