Parr Instrument 6400 - Manual (Page 19)

6400
Calorimeter Instruction Manual
3-1
QUICK START
1. Turn on the heater and pump in the Calorimeter Operation menu. Allow at least 20
minutes for the calorimeter to warm up.
2. Initiate a pretest to run the calorimeter through the fill and cool/rinse cycles. This
function is used to pre-condition the calorimeter if it has been sitting idle for an extended
period of time (greater than 15 minutes).
3. Prepare and weigh the sample to 0.0001g.
4. Gently tap capsules that contain powdered samples to compact the material. (Pellets
are easier to handle than loose samples and they burn slower in the bomb, thereby
reducing the chances for incomplete combustion).
5. Carefully place the capsule into the capsule holder, attach 10 cm of ignition thread and
install the bomb head in the calorimeter.
6. Close the calorimeter cover making sure that the latch is engaged.
7. Select determination or standardization as appropriate on the Calorimeter Operation
page, by toggling the operating mode key. Press the Start Key. The calorimeter will
now prompt the operator for Bomb ID number, sample ID number, sample weight and
spike weight in accordance with the instructions set into the operating controls page.
8. The calorimeter will now take over and conduct the test. During the time it is establishing
the initial equilibrium, it will display PREPERIOD on the status bar. Just before it fires
the bomb, it will sound a series of short beeps to warn the user to move away from the
calorimeter. Once the bomb has been fired, the status bar will display POSTPERIOD.
The calorimeter will check to make certain that a temperature rise occurs and will then
look for the final equilibrium conditions to be met. If it fails to meet either the initial or
final equilibrium conditions, or if it fails to detect a temperature rise within the allotted
time, the test will terminate and advise the user of the error.
9. At the conclusion of the test, the calorimeter will signal the user.
10.
Open the cover and remove the head. Examine the interior of the bomb for soot or other
evidence of incomplete combustion. If such evidence is found, the test will have to be
discarded.
11. Titrate the bomb washings with a standard sodium carbonate solution using methyl
orange, red or purple indicator. A 0.0709N sodium carbonate solution is recommended
for this titration to simplify the calculation. This is prepared by dissolving 3.76 grams of
Na
2
CO
3
in the water and diluting to one liter. NaOH or KOH solutions of the same
normality may be used.
12. Analyze the bomb washings to determine the sulfur content of the sample if it exceeds
0.1%. Methods for determining sulfur are discussed in Analytical Methods for Oxygen
Bombs, No. 207M.