Isothermal Conduction Calorimeter
Software for JAF Isothermal Conduction Calorimeter
The JAF conduction calorimeter is designed to measure
the isothermal heats of hydration of small samples of
The principle on which the calorimeter works is that
heat generated during the chemical reaction flows rapidly
through a thermal conductor formed by a sensitive thermopile
which produces an electrical output proportional to the heat
flow through it.
The output signal is monitored by a micro-voltmeter connected
to the RS232 serial port of a computer.
The input to the voltmeter is switchable between the two
calorimeters which form the basis of the system.
A simple question and answer software
package guides the user through the following stages.
- Two scan rates selectable from 0.5minutes upwards e.g.
- scan at 3 - 6minute intervals for the first 48hours where the hydration rate is changing considerably
- scan at 10 - 15minutes from 48hours onwards
After the reaction rate returns to a stable level, the calorimeter is calibrated by applying a known voltage to a small heater inside the sample container. This voltage is left on for around 1 hour and readings are taken every
0.5 - 1 minute.
Analysis of Calibration Data
A linear regression analysis is applied to the output signals
generated by the calibration. The values obtained
from this analysis are then used in the Tian
Calvet equation to calculate the calorimeter constants.
The calorimeter constants are used to convert the output
from the test run into the rate of heat output in kJ/kg.
The rate of heat output curve is integrated to give the
total heat output curve.
During the test, the output signals from both calorimeters
are displayed on the VDU screen.
After the test is complete, the output data for all three
plots ( rate of heat, total heat and calibration ) are stored as
data in separate files.
These curves can then be plotted using a suitable software
The software, is written in compiled basic so that it will run
computer ( 286, 386 or better ) which supports MSDOS.