KD2 Pro 5 TAKING MEASUREMENTS
5.5 Liquid Sample Temperature Control
Often it is desirable to control the temperature of the liquid sam-
ple above or below ambient temperature during thermal properties
measurement. It is important that the act of heating or cooling the
sample does not cause forced or free convection as mentioned above.
There are several things that should be avoided when measuring ther-
mal properties of heated or cooled samples. Cautions:
Do not heat the sample from the bottom (e.g. on a hot
plate). The temperature gradient from the heating causes
free convection.
Do not make measurements in a conventional refrigerator
or freezer. Conventional cooling devices have very large
cyclical temperature cycles which can cause excessive sam-
ple temperature drift and poor measurements. Vibrations
from the compressor also causes forced convection in the
sample.
Do not measure the thermal properties of the sample while
it is in a circulating water bath. The vibrations from the wa-
ter bath pump and from the circulating water causes forced
convection in the sample.
Controlling Temperature
Several researchers who use the KD2 Pro with liquid samples sug-
gest the following three steps as the best method for controlling the
temperature of liquid samples.
1. Heat or cool the sample (with sensor inserted) in a water bath.
2. Once the sample temperature has equilibrated to the desired
water bath temperature, turn the water bath off.
3. Allow enough time for the water bath to become absolutely
still, and make the measurement.
Note: Experimental results from researchers have shown that the
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