Calibration; Preparing And Performing Measurements; Decomposition Vessel C 5010 - IKA C 200 Operating Instructions Manual

5.4 Calibration

The calorimeter system must be calibrated before
accurate measurements are possible. This is done
by combusting tablets made of certified benzoic
acid (see Accessories) with a known calorific va-
lue. The heat quantity required to raise the tem-
perature of the calorimeter system by one Kelvin
is used to determine the heat capacity of the so-
called "C-value" of the system. For this calculati-
on the formula (1) (see section 5.1) is adapted:
C = (Ho * m + QExt1 + QExt2) / DT
This value is used for determining the following
calorific values.
The heat capacity is determined by the measu-
ring cell and the decomposition vessel. It has a
significant influence on the calorific value to be
calculated and must be redetermined in particular
when using for the first time, after servicing and
when parts are replaced. A monthly control mea-
surement is recommended.

Preparing and performing measurements

The term "measurements" below refers to both
the measurements to calibrate the calorimeter
system (calibration measurements) and the actual
measurements for determining the calorific value.
The difference lies in the calculation (cf. section
5, formulae (1) and (2)), whereas preparation and
performance are virtually identical.
Exact measurements are only possible when the
individual test steps are carried out carefully.
You must therefore follow the exact proce-
dure described in section 1 "For your safe-
ty" and in the following sections
Please also see section 5 "Calorimetric measure-
ments".
Failure to observe these instructions could re-
sult in damage to the decomposition vessel.
Damaged decomposition vessels could crack!
Follow the operating instructions for the de-
composition vessel!
The system must be calibrated in every work
mode used.
If a calorimeter is operated with several de-
composition vessels, you will need to deter-
mine the heat capacity of the system for each
decomposition vessel.
Ensure that calibration is carried out under the
same conditions as the subsequent tests. If sub-
(2)
stances are used in the decomposition vessel in
combustion tests (e.g. distilled water or solu-
tions), you must use exactly the same amount of
this substance for calibration.
For more detailed information on calibration, ple-
ase see the relevant standards.

6.1 Decomposition vessel C 5010


Electric
ignition
contact

Ignition
wire

Crucible
holder
If several decomposition vessels are used,
their individual parts must not be interchan-
ged (see Stamping individual parts).
To prolong the life of wearing parts (o-rings,
seals, etc.) we recommend that you always
work with a water trap.

Union nut

Oxygen valve

Cover

Crucible
19