70Xi Cold Flow Properties Laboratory Analyzer
User Guide
36
In a pour point test, the sample starts off in a wax-free liquid state, and is then cooled. As it cools, it
becomes more viscous as wax crystals begin to form. Pour point is the minimum temperature at which the
liquid still flows before gelling or becoming sufficiently viscous and immobile under the test conditions.
The 70Xi Analyzer detects the pour point by shooting a calculated pulse of compressed gas onto the
sample surface. This creates disturbances in the sample. The 70Xi Analyzer’s optical sensors take a
sequence of pictures to detect this movement. Absence of movement indicates that the pour point has
been reached.
The phase plot shows temperature on the horizontal axis and signal on the vertical axis. The signal is an
indication of the amount of movement experienced by the sample.
As the sample is cooled, green bars show the magnitude of movement (read from right to left). Pour point
is determined at the lowest level of temperature at which the sample still shows some movement.
The green movement bars are plotted at the selected resolution, but typically every 3°C (or 5°F) . Users
can choose a resolution as small as 0.1°C if they wish
.
