Method using flux sensors to determine the output of a thermal reaction within a housing and device for carrying out such a method

1. Method for determining an exchange area A between a reagent and a wall of a housing containing this reagent, in order to determine in particular a power P r of a thermal reaction inside the housing and a heat exchange coefficient U between the reagent and the wall of the housing,

comprising:

measuring a first heat flux F 1 per surface unit taken in a first zone of the wall in secure contact with the reagent,

measuring a second heat flux F 2 per surface unit taken in a second zone of the wall in secure absence of contact with the reagent,

measuring a third heat flux F 3 per surface unit taken in a third zone of the wall comprising, in a continuously overlapping manner, both a zone of the wall in secure contact with the reagent next to a zone of the wall in secure absence of contact with the reagent,

calculating, based on proportions of the measurements of the first, second, and third heat flux which have been carried out, the actual level h of the reagent inside the housing,

so that the actual exchange area A between the reagent and the wall of the housing containing this reagent can be determined continuously and in real time, based on the calculated actual level h of the reagent, and with respect to any given geometry of the housing.

2. Method according to claim 1 , applied to the determination of the power P t transmitted by the housing,

comprising:

measuring the first heat flux F 1 per surface unit,

determining the exchange area A between the reagent and the wall of the housing,

so that the power P t transmitted by the housing can be calculated, continuously and in real time, with a precision and a reliability derived from those of the exchange area A.

3. Method according to claim 2 , applied to the determination of the heat exchange coefficient U between the reagent and the wall of the housing,

comprising:

measuring the temperature T r of the reagent and the temperature T e of the wall of the housing,

determining the actual exchange area A between the reagent and the wall of the housing,

calculating the power P t transmitted by the housing,

so that the heat exchange coefficient U between the reagent and the wall of the housing can be calculated continuously and in real time, with a precision and a reliability derived from those of the exchange area A.

4. Method according to claim 2 , applied to the determination of the power P r of the reaction,

comprising:

measuring the evolution of the temperature T r of the reagent as a function of the reaction time,

determining the power P t transmitted by the housing,

estimating the thermal losses of the housing,

so that the power P r of the reaction can be calculated, continuously and in real time, with a precision and a reliability derived from those of the exchange area A.

5. Method according to claim 1 , applied to the measurement of the variation of the level h of a reagent inside a housing, until a security threshold is reached.

6. Device for measuring an exchange area A between a reagent and a wall of a housing containing this reagent,

comprising:

a housing designed to receive the reagent,

a first heat flux sensor for measuring the first heat flux F 1 per surface unit, this heat flux sensor being arranged at the external wall of the housing in a zone opposed to a first zone of its internal face in secure contact with the reagent,

a second heat flux sensor for measuring the second heat flux F 2 per surface unit, this heat flux sensor being arranged at the external wall of the housing in a zone opposed to a second zone of its internal face in secure absence of contact with the reagent,

a third heat flux sensor for measuring the third heat flux F 3 per surface unit, this heat flux sensor being arranged at the external wall of the housing in a zone opposed to a third zone of its internal face, said third zone being both in presence and in absence of contact with the reagent.

7. Device according to claim 6 ,

comprising first electronic means for calculating the level h of the reagent from logical voltage data provided by the first, second, and third flux sensors, and second electronic means for calculating the actual exchange area A between the reagent and the wall of the housing.

8. Device according to claim 6 , applied to a calorimeter,

comprising a jacket surrounding the housing for the circulation of a fluid around this housing, this fluid being thermostatted by heat-producing means, so as to maintain the housing at a desired temperature.

9. Device according to claim 8 ,

comprising:

a first temperature sensor placed inside the housing to measure the temperature T r of the reagent,

a second temperature sensor placed inside the jacket to measure the temperature T e of the wall of the housing from the temperature T f of the thermostatted heat-transfer fluid inside the jacket.

10. Device according to claim 9 ,

comprising third electronic means for calculating the power P t transmitted by the housing and fourth electronic means for calculating the heat exchange coefficient U between the reagent and the wall of the housing, from the logical data provided by the second electronic calculation means and from the logical data provided by the first and second temperature sensors.

11. Device according to claim 10 , comprising fifth electronic means for calculating the power P r of the thermal reaction from the logical data provided by the third electronic calculation means and by the first temperature sensor.

12. Device according to claim 6 ,

wherein the first, second, and third heat flux sensors constitute general means for determining continuously the level h of a reagent inside the housing, in association with the first calculation means.

13. Device according to claim 7 , comprising third electronic means for calculating the power P t transmitted by the housing, fourth electronic means for calculating the heat exchange coefficient U between the reagent and the wall of the housing, from the logical data provided by the second electronic calculation means and from the logical data provided by the first and second temperature sensors, and fifth electronic means for calculating the power P r of the thermal reaction from the logical data provided by the third electronic calculation means and by the first temperature sensor,

wherein the first, second, third, fourth, and fifth electronic calculation means are grouped in general memory and electronic calculation means.

14. Device according to claim 13 , comprising a calculator comprising:

general memory and electronic calculation means,

means for displaying various measured and calculated logical data,

means for capturing data and controlling the general memory and electronic calculation means.