Parr Instrument 6400 - Manual (Page 24)

6400
Calorimeter Instruction Manual
4-5
who intend to test these materials are urged to select the 1138CL Bomb. These bombs
are 250 mL in volume and are rated to a maximum working pressure of
2000 psi. The
bombs are hydrostatically tested to 3000 psi and the sample range is ~1g or 5000 – 8000
calories.
Explosives and High Energy Fuels
Materials which release large volumes of gas which detonate with explosive force or
burn with unusually high energy levels, should not be tested in this calorimeter. Rather,
they should be tested in a model 6100 or 6200 Calorimeter which can be equipped with
an 1104 High Strength Oxygen Bomb designed specifically for these types of samples.
Volatile Sample Holders
Volatile samples are defined as one with an initial boiling point below 180ºC per ASTM
D-2. Volatile samples can be handled in a Parr 43AS Alloy Capsule which has a sturdy
wall with a flat top rim. These holders can be sealed with a disc of plastic adhesive tape
prepared by stretching tape across the top of the cup and trimming the excess with a
sharp knife. The seal obtained after pressing this disc firmly against the rim of the cup
with a flat blade will be adequate for most volatile samples. The tape used for this
purpose should be free of chlorine and as low in sulfur as possible. Borden Mystic Tape,
No. M-169-C or 3M Transparent Tape, No. 610, are recommended for this purpose. The
3M Transparent Tape can be ordered through Parr, Part No. 517A.
Figure 4 - Volatile Sample Technique
The weight of the tape disc must be
determined separately and a correction
applied for any elements in the tape
which might interfere with the
determination. The approximate Heat of
Combustion of the tape is 6300 cal/g. An
actual amount should be determined by
running a blank test with tape alone using
a sample weighing 1.0 gram. The
compensation for heat of tape may be
done through the spike option; see Spike
Controls, Heat of Combustion of Spike.
Note:
Tape should always be stored in a sealed container to minimize changes in
its moisture and solvent content.
Use the following procedure when filling and handling any of these tape-sealed sample
holders:
1. Weigh the empty cup or capsule; then cover the top with tape, trim with a knife
and press the trimmed edge firmly against the metal rim. Also cut and attach a
small flag to the disc (see Figure 4).
2. Puncture the tape at a point below the flag, then re-weigh the empty cup with its
tape cover.
3. Add the sample with a hypodermic syringe; close the opening with the flag and
re-weigh the filled cup.