Parr Instrument 1356 - Manual (Page 5)

5
1. Calorimeter Operation
A. Operating the Calorimeter
All operations required to standardize the Calorimeter, or test an unknown sample, should
proceed step-wise in the following manner:
1. Turn on the calorimeter, go to menu page 1 and press YES key on line 3 to
activate the pump and heater.. The bomb parts should be wetted and then dried in
the manner used at the conclusion of a test. This serves to wet all sealing parts, as
well as leaving the bomb with the same amount of residual water which will exist
in all subsequent testing.
Prepare the sample and charge the oxygen bomb by attaching the hose to the
bomb and pressing the O2 Fill key.
The throughput of the 1356 Calorimeter can be increased by using multiple
bombs and water buckets. With this arrangement, the calorimeter can operate
almost continuously since the operator will be able to empty a bomb and recharge
it while a run is in progress. A bomb and bucket for the next run will be ready to
go into the calorimeter as soon as it is opened. Each bomb and bucket
combination will have to be standardized separately and the proper energy
equivalent for each set must be used for the heat of combustion calculation.
2. Fill the calorimeter bucket by first tarring the dry bucket on a solution or trip
balance; then add 2000 (+/- 0.5) grams of water. Distilled water is preferred, but
de-mineralized or tap water containing less than 250 ppm of dissolved solids is
satisfactory. The water temperature should be approximately 1 to 2ºC below the
room temperature. It is not necessary to use exactly 2000 grams, but the amount
selected must be duplicated within +/-0.5 gram for each run. Instead of weighing
the bucket, it can be filled from an automatic pipette, or from any other
volumetric device if the repeatability of the filling system is within +/-0.5 ml. Try
to make the starting temperature as repeatable as possible.
3, To speed and simplify the bucket filling process, and to conserve water and
energy, Parr offers a closed-circuit Water Handling System (No. 1563). This
provides a water supply, cooled to the starting temperature and held in an
automatic pipette ready for delivery in the exact amount needed to fill the bucket.
A 1552 Water Cooler is required when using the 1563 Water Handling System.
Instructions for this automatic system are given in Operating Instruction No. 245
and 246M.
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 operation so that the sample will not be disturbed. Push the
two ignition lead wires into the terminal sockets on the bomb head. Orient the
wires away from the stirrer shaft so they do not become 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. Check for any bubbles coming from the
bomb, if bubbles are seen, do not fire the bomb. Resolve the problem.
5. Close the calorimeter cover