Parr Instrument 1341 - Manual (Page 5)

1341 Plain Jacket Calorimeter
w w w . p a r r i n s t . c o m 5
Assemble the Calorimeter
1. Unpack the calorimeter carefully and check the
individual parts against the packing list. If ship-
ping damage is discovered, report it immedi-
ately to the delivering carrier. Unpack the jacket
first and set it on a sturdy bench or table in a
location that is reasonably free from drafts and
is protected from sources of radiant heat, prefer-
ably in an air conditioned room. Temperature
changes in the room should be minimal.
There should be convenient access to running
water, to a drain and to an appropriate grounded
electrical outlet. About 8 square feet of work-
space will be required. Access to a chemical bal-
ance sensitive to 0.1 mg and to a solution, trip or
torsion balance capable of weighing up to 3.0 kg
with 0.1 g sensitivity will be required. A stan-
dard 1A cylinder with a purity of 99.5% is usually
sufficient for bomb combustion purposes.
2. Set the cover on the jacket. Remove the two
screws from the side of the jacket and attach the
stirrer drive motor. Check the stirrer shaft to be
sure that it turns freely and slip the drive belt
onto the motor and stirrer pulleys.
3. Assemble the cover support stands. Two stands
are furnished, each consisting of a base, a sup-
port rod and ring to be clamped to the upper end
of the rod. The A37A stand with the large ring is
used to support the calorimeter cover when it is
removed from the jacket, while the A38A stand
with the smaller ring supports the bomb head
when attaching the fuse wire and arranging the
fuel capsule.
4. Install the thermistor by sliding it through the
opening in the calorimeter cover. Adjust the
length of the thermistor to match the length of
the stirring shaft. Hand tighten the nut to secure
the thermistor.
Note: Do not over tighten the nut.
Once installed, the thermistor can remain at-
tached to the cover during all operations. Do not
lay the cover on the tabletop. Always set it in
the supporting ring on the A37A stand to protect
the thermistor and stirring shafts.
5. Check the calorimeter bucket, noting the three
dimples in the bottom of the bucket which rest
on supporting pins in the bottom of the jacket.
The single dimple must always face forward
when setting the bucket in the jacket.
6. Connect the ignition unit. While any electrical
system capable of furnishing approximately 23
volts can be used to ignite the fuse in the oxygen
bomb, most users will prefer to use a Parr 2901
Ignition Unit for this purpose. This unit operates
from any standard electrical outlet to provide the
proper low voltage firing current, providing also
a convenient push switch, indicating lamp and
connecting terminals.
Connect one of the lead wires from the calo-
rimeter jacket to the terminal labeled “10CM”.
Connect the second lead to the terminal labeled
“Common”. Plug the power cord into an appro-
priately grounded electrical outlet. The power
supply cord is the main electrical disconnect
device for the ignition unit. After the unit has
been plugged into an outlet do not press the
firing button unless the lead wires inside the
jacket are connected to the combustion vessel.
7. Attach the oxygen filling connection. Unscrew
the protecting cap from the oxygen tank and
inspect the threads on the valve outlet to be sure
they are clean and in good condition. Place the
ball end of the 1825 Oxygen Filling Connection
into the outlet socket and draw up the union
nut tightly with a wrench, keeping the 0-55 atm.
gage in an upright position.
Operating instructions for the 1825 Oxygen Filling
Connection are provided in Instruction Manual
205M for the 1108 Oxygen Combustion Vessel.
Operating the 1108 Oxygen Vessel
Detailed instructions for preparing the sample and
charging the 1108 Oxygen Combustion Vessel are
given in Instruction Manual, No. 205M. Follow
these instructions carefully, giving particular atten-
tion to the precautions to be observed in charging
and handling the bomb.
Caution!
If the bare terminals on these wires happen
to be in contact with each other or with a
metal object when the circuit is closed, the
resulting short-circuit may cause serious
damage to the ignition system.