| 摘要 |
A structure of calorimeter provides a calorimetric head (1) comprising a calorimetric cell (10) suitable for receiving a sample holding container (20) containing a sample (25) to examine. The cell (10) is arranged according to a first shield (3), or active shield. Outside the active shield (3) a second shield (4), or dynamical shield is present, which comprises a cylindrical hollow body arranged around the active shield (3) for all its length in order to provide a space (5) of determined size. Outside the active shield a thermal bath is present (not shown) at a temperature lower than the first and the second shield (3,4). The dynamic shield (4) allows an effective adjustment of the heat flux through the active shield (3) during calorimetric measures by limiting the heat flux same. In fact, in operative conditions the dynamic shield acts as thermal flywheel and keeps constant the heat flux coming from the active shield (3). More in detail, the presence of the dynamic shield (4) ensures the reduction of the temperature gradient on the active shield (3) and then on the cell (10) containing the sample (20). Furthermore, by keeping the dynamic shield (4) at a suitable temperature difference from the active shield (3), the temperature can be controlled with much less electric power than it would be necessary if the active shield (3) exchanged heat directly with the thermal bath.
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