DTC-300 Getting Started Guide
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The sample can be stacked on a reference material and tested together with it. It is recommended that
one of the reference materials used for the instrument's calibration should be considered for this partic-
ular application. The reference material has to be tested first by itself, and then together with the sam-
ple. The difference between the two thermal resistance values measured represents the sample’s
thermal resistance. Knowing the thermal resistance and the thickness, the thermal conductivity can be
calculated.
Non-Solid Sample Testing
The DTC-300 can be used to measure the thermal conductivity of non-solid samples with optional test
cells, available as instrument accessories, if needed. This allows testing of pastes, gels, liquids, polymers
through-the-melt, and other highly viscous substances in the range 0.1 to 1.0 W/(m.K).
Each cell has its own construction for the containment of the sample to be tested during operation. The
paste cell and polymer melt cell are described in the following sections, but the liquid cell follows the same
basic operating principle.
Before testing non-solid samples with the paste cell, the DTC-300 must be calibrated with reference mate-
rials placed inside the cell. Regular instrument calibrations, obtained without the paste or melt cell, cannot
be used when testing non-solids with the cell. Calibration references for the paste and melt cells are solid
samples of known thermal conductivity similar to those used for normal equipment calibration.
Paste Cell Testing
The paste cell consists of two thermally conducting metal plates separated by a set of insulating rings. The
inner ring is a spacer to keep the metal plates at a fixed distance. The outer ring is primarily a container for
the specimen material. Each cell is provided with two sets of rings including a 0.2” (5.08 mm) spacer and a
0.4” (10.16 mm) spacer.
If the expected thermal conductivity of the sample material is between 0.1 and 0.7 W/(m.K), use the 0.2”
spacer in the test cell. If the expected thermal conductivity is between 0.4 and 1.0 W/(m.K), use the 0.4”
spacer.
Follow the
procedure for a normal test without the cell
, except that, in this case, the paste cell with test
sample must be placed in the DTC-300. Follow the instructions below for installing non-solid material in
the cell.
1
The paste cell consists of 4 separate components: The bottom plate, outer ring, inner ring and top plate.
Select a set of rings based on the expected
λ
of the sample material. Accurately measure and record the
thickness of the inner ring (spacer).
2
Hold the outer ring with its rim toward the bottom. Insert the bottom metal plate (flange side facing up)
in the outer ring and slide the plate all the way down until the flange comes to rest against the lower rim.
Insert and lower the inner ring (spacer) until it reaches the metal plate.
3
Fill the space inside the inner ring with non-solid sample material until it rises slightly above the level
of the inner ring. Put slightly more material in the center of the cell than toward the edges. Stir the
material to make sure that there are no bubbles and voids.
4
Insert the upper metal plate (the one with the small holes along the perimeter) in the cell and push it
down until it makes contact with the spacer.
NOTE
: The holes in the plate are drilled at a small angle. The side of the plate where the holes are farthest
apart is the top. The below images show the top of the plate on the left and the bottom of the plate on the
right.
