Operation – Parr Instrument 6755 User Manual

Page 13

Operation

6755

w w w . p a r r i n s t . c o m

Emptying the Calorimeter

Stop the calorimeter motor, raise the cover carefully
and wipe any excess liquid from the parts that were
immersed in the Dewar. Remove the thermistor
probe from the cover and remove the sample dish
from the end of the push rod; then remove the rod
and release the glass cell from the drive shaft. Lift
the Dewar out of the air can and empty it; then wash
and dry all wetted parts carefully.

The two operating modes, (manual or automatic)
are outlined below:

Manual Test Sequencing

Some users may wish to construct their own thermo
gram and apply the classic graphical corrections de-
veloped by Dickenson and others. In this case, the
actual temperatures can be logged to the memory
of the thermometer and then analyzed at the end of
the test. These logged temperatures can be printed
on an attached printer or transferred to a computer
using an SD Card. The Ethernet Connection can also
be used to transfer temperatures to a computer for
plotting.

First, select the appropriate jacket temperature
source as described previously. Then ﬁ ll the Dewar.
Next, prepare and load the reaction. After the calo-
rimeter is fully assembled, turn on the motor, and
then turn on the stirrer by pressing the stirrer key on
the calorimeter operation menu screen. Turn on the
data logger (accessed via the Diagnostics page) in
order to periodically record the bucket or calorime-
ter temperature. The bucket temperature is updated
every 10 seconds. Turn on the calorimetric pre-
period. The pre-period should last for 6-7 minutes.
After the 6-7 minute pre-period test phase, start the
reaction by pressing the push rod downward to
drop the sample out of the rotating cell. This be-
gins the reaction and subsequent post-period. The
calorimeter temperature should begin to signiﬁ -
cantly change at this point, indicating sample reac-
tion. The calorimetric post-period should last for an
additional 6-7 minutes from sample introduction. At
the conclusion of the post-period, turn the stirrer off
by pressing the stirrer key once again. The motor
switch may be left in the “on” position for subse-
quent tests. Empty and clean the calorimeter.

If the data log destination is a log ﬁ le, the log ﬁ le is
located at /ﬂ ash/log/datalog.csv and may be re-
trieved via FTP. The log ﬁ le is easily imported into a
spreadsheet program where the calorimeter tem-
perature can be plotted in order to realize a thermal
curve. Instructions for working with or analyzing
thermal curves are found in the calculations section.

Automatic Test Sequencing

The solution calorimeter will perform all calcula-
tions for the user. To do this, ﬁ rst select the ap-
propriate jacket temperature source. For most
applications, the calculated jacket approach works
well. First, select the appropriate jacket temperature
source as described previously. Then ﬁ ll the Dewar.
Next, prepare and load the reaction. After the calo-
rimeter is fully assembled, turn on the motor, and
then press the START key located on the right hand
side of the screen. This will activate the stirrer that
gently circulates the ﬂ uid that surrounds the glass
cell. The thermometer will prompt for the sample
ID number. This begins the calorimetric pre-period.
After the thermometer determines that adequate
temperature equilibrium is realized, the thermom-
eter will prompt the user to start the reaction by
pressing the push rod downward to drop the sample
out of the rotating cell. This starts the calorimetric
post-period. The calorimeter temperature should
begin to signiﬁ cantly change at this point, indicating
sample reaction. The calorimetric post-period will
last for an additional 6-7 minutes until the calorim-
eter temperature drift rate sufﬁ ciently stabilizes. At
the end of the post-period the calorimeter will signal
the end of the test and generate a report.