5 TAKING MEASUREMENTS KD2 Pro
To eliminate forced convection, the fluid sample and the sensor must
be absolutely still during the measurement. Even minute vibrations
in the sample are often enough to compromise the thermal proper-
ties measurement. Some common sources of vibrations found in the
laboratory that have been shown to affect thermal properties mea-
surement in liquids and must be avoided include:
• HVAC (Heating, Ventilating, and Air Conditioning) systems
• Computer fans that are near the measurement apparatus
• People moving around the lab
• Other laboratory equipment
If sources of vibration are present in laboratory, it may be necessary
to place the sample on a vibration isolation table to prevent errors
from convection. Another common strategy is to configure the KD2
Pro in auto mode and make measurements overnight after turning
off the HVAC system and any other lab equipment that might cause
vibrations.
The KD2 Pro KS-1 sensor is specially designed to add a very small
amount of heat to the sample during measurement and thereby min-
imize problems with free convection. In high viscosity liquids (e.g.
oils, glycerin), free convection is generally not an issue. However, in
low viscosity liquids like water or aqueous solutions, there are several
important tips to aid you in obtaining accurate measurements.
• When dealing with low viscosity liquid samples, the duration
of the read time should be as small as possible to minimize the
amount of heat added to the sample.
• The default read time for the KS-1 sensor is one minute. If you
are measuring in low viscosity liquids, use this read time.
• In liquid samples, the KS-1 sensor needle should be oriented
vertically during the measurement to help prevent free convec-
tion.
• Never use the KS-1 sensor in high power mode in liquids. The
sensor must be configured in low power mode to prevent free
convection.
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