Temperature
readings were transferred via wireless transmitterdirectly to a PC workstation. The data were recorded in
MS Excel through a specially developed subroutine
(macro written in MS Visual Basic). Temperatures were
measured with a 0.3 C resolution in 10 s time steps. The
temperature of the wall was recorded manually directly
from the PID controller display, with a 0.1 C resolution. The homogeniser was equipped with a frequency
converter, enabling to change the rotational speed of
the scraping blades and to study the heat transfer dependence upon the rotational speed. Experiments were carried out for a single filling of each product, at three
rotational speed levels.