Parr Instrument 6100 - Manual (Page 21)

Operating Instructions
6100 5
w w w . p a r r i n s t . c o m 19
4. Set the bucket in the calorimeter. Attach the
lifting handle to the two holes in the side of the
screw cap and partially lower the bomb in the
water. Handle the bomb carefully during this op-
eration so that the sample will not be disturbed.
Push the two ignition lead wires into the termi-
nal sockets on the bomb head. Orient the wires
away from the stirrer shaft so they do not be-
come tangled in the stirring mechanism. Lower
the bomb completely into water with its feet
spanning the circular boss in the bottom of the
bucket. Remove the lifting handle and shake any
drops of water back into the bucket and check for
gas bubbles.
5. Close the calorimeter cover. This lowers the stir-
rer and thermistor probe into the bucket.
6. Select determination or standardization as ap-
propriate 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 num-
ber, sample weight and spike weight in accor-
dance with the instructions set into the Operat-
ing Controls page.
7. 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 dis-
play 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
calorimeter will terminate the test and advise the
user of the error.
8. At the conclusion of the test, the calorimeter will
signal the user.
9. Open the cover and remove the bomb and
bucket. Remove the bomb from the bucket and
open the knurled valve knob on the bomb head
to release the residual gas pressure before at-
tempting to remove the cap. This release should
proceed slowly over a period of not less than
one minute to avoid entrainment losses. After
all pressure has been released, unscrew the cap;
lift the head out of the cylinder and 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. Oth-
erwise, wash all interior surfaces of the bomb,
including the head, with a jet of distilled water
and collect the washings in a beaker.
10. Titrate the bomb washings with a standard
sodium carbonate solution using methyl orange,
red or purple indicator. A 0.0709N sodium car-
bonate solution is recommended for this titra-
tion to simplify the calculation. This is prepared
by dissolving 3.76 grams of Na2CO3 in the water
and diluting to one liter. NaOH or KOH solutions
of the same normality may be used.
11. Analyze the bomb washings to determine the
sulfur content of the sample if it exceeds 0.1%.
Methods for determining sulfur are discussed in
Operating Instructions No. 207M.
12. At the end of the testing period, go to the main
menu and press the key. Press YES to con-
firm System Shutdown. Turn off the calorimeter
at the power switch when prompted by the
display.