DTC-300 Getting Started Guide
Page 29
10
Turn the chiller on to the desired temperature. For a -20°C approximate mean sample testing temperature,
the chiller should be set to -40°C or colder.
Testing the Sample
•
To setup the DTC-300 to test at sub-ambient temperatures the following items are needed:
•
The sub-ambient insulation ring
•
A tank of dry inert gas
•
A chiller and coolant capable of sub-ambient temperature operation, (-35 to -40°C).
•
If coolant needs to be emptied out of the chiller, then a funnel and/or an empty container(s) are
necessary.
1
Prepare a sufficient amount of empty containers to handle the coolant to be removed from the chiller
bath. Empty the coolant into the containers using a funnel. The below figure shows a chiller with a drain
plug being emptied into a container. It is recommended to mark the container “Used Coolant” to avoid
any confusion at a later time.
2
The coolant inside of the DTC-300 stack and lines also need to be emptied. Disconnect both coolant
lines from the back of the chiller. Place one line into a container and blow through the other line using
an external air supply. A small amount of coolant left in the chiller or unit is acceptable.
3
Re-connect the coolant lines to the chiller.
COOLANT OUT
from the unit to
COOLANT IN
on the
chiller.
COOLANT IN
from the unit to the
COOLANT OUT
on the chiller.
4
Fill the chiller bath with the adequate coolant specified by the manufacturer of the chiller being used for
testing temperatures near -20°C (chiller temperature set at -35 to -45°C).
5
Open the front cover of the unit. Lift the guard heater to the top locking position.
6
Load the sample. Refer to the section
Loading the Sample
for instructions.
Unknown Sample Testing
To perform a thermal conductivity measurement on an unknown sample:
1
Check that the
HEATER POWER
switch on the front panel is
OFF
(no red is visible on the switch).
Activate the instrument by pressing the main power switch next to the power input socket in the rear
panel. Check that there is coolant flowing through the heat sink.
2
Check the air pressure reading on the gauge. If necessary, adjust the air pressure.
3
Release the latches and open the front door. Raise the guard furnace and lock it in the elevated position,
thus providing access to the test stack. Raise the upper heater assembly by toggling the
UP
/
DOWN
switch.
4
Determine which stack spacer should be used to obtain the desired reference temperatures for the
upcoming test, and place the appropriate spacer in the instrument’s stack.
5
Measure and record the sample’s thickness and apply a small amount of thermal compound to both of
its faces.
6
Place the sample on the exposed surface of the bottom heater assembly and align it with the lower stack.
7
Lower the top heater assembly with the
UP
/
DOWN
switch. Check to make sure that the sample is
centered between the two metallic surfaces and realign it, if necessary. Remove any excess thermal
