The system is completely computer-controlled and features a range of high-pressure test cells, magnetic stirring and pressure and temperature logging. Standard pre-programmed Tests make runs quick and efficient and simple standard test cells keep consumable costs to a minimum.
A time-consuming feature of traditional “ARC-type” calorimeters, which also leads to poor results, is the empirical method used to “calibrate” the system in order to produce adiabatic conditions. HEL uses a proprietary model developed exclusively for phi-tec that uses an on-line calibration technique based on a mathematical model and which keeps the system in constant calibration without the need for lengthy runs.
Samples are stirred as standard and both liquid and powder samples can be tested.
The system employs two standard test types
…For the early screening of liquids and powders, with a view to assessing their thermal stability and explosion potential in a matter of an hour or so. This involves ramping the sample temperature until an exotherm is induced – analogous to a DSC test, but with the added feature of pressure data, a larger and more reliable sample size and ability to stir the sample while heating.
This is the classical “ARC” test developed by Dow and widely used for decades. This provides more accurate data as the sample is heated stepwise with pauses in between heatings to “search” for an exotherm within the sensitivity of the device. Once an exotherm is detected, adiabatic tracking commences, without any external heating, essentially allowing the exotherm to drive the runaway.