Thermo-analytical instrument

Abstract

A thermo-analytical instrument, especially a differential scanning calorimeter has a sample position ( 201, 401 ) for receiving a sample ( 206 ), a reference position ( 202, 402 ), a heating means associated with the sample position and the reference position, a means for setting a predetermined temperature program of nominal values of temperature versus time, a first sensor ( 407 ) for measuring a sample temperature (T S ) at the sample position, and a controller. The controller controls the heating power of the heating means so that measured sample temperature essentially follows the predetermined temperature program.

1 . An instrument for thermo-analytical analysis of a sample, comprising:
 a sample position for receiving the sample;   a reference position;   a means for heating, associated with the sample position and the reference position;   a means for setting a predetermined temperature program of nominal values of temperature versus time;   a first sensor for measuring a temperature of the sample at the sample position;   a second sensor for measuring a reference temperature at the reference position; and   a controller for controlling the heating power of the heating means in a manner that causes the measured sample temperature to essentially follow the predetermined temperature program, with a differential in temperature between the sample temperature and the reference temperature representing a measurement signal.   
     
     
         2 . The thermo-analytical instrument of  claim 1 , wherein:
 each sensor comprises at least one of: a thermopile arrangement with at least one thermocouple, a resistance temperature sensor and a semiconductor based temperature sensor.   
     
     
         3 . The thermo-analytical instrument of  claim 2 , wherein:
 a reference substance is associated with the reference position.   
     
     
         4 . The thermo-analytical instrument of  claim 3 , wherein:
 the heating means comprises a common heater associated with the sample position and the reference position.   
     
     
         5 . The thermo-analytical instrument of  claim 3 , wherein:
 the heating means comprises:
 a reference heater, associated with the reference position; and 
 a sample heater associated with the sample position. 
   
     
     
         6 . The thermo-analytical instrument of  claim 5 , further comprising:
 a common holder, on which is arranged both the sample position and the reference position.   
     
     
         7 . The thermo-analytical instrument of  claim 1 , wherein:
 the sample position and the reference position are intrinsically symmetrical.   
     
     
         8 . The thermo-analytical instrument of  claim 1 , wherein:
 the thermo-analytical instrument is a heat flux calorimeter operated under isoperibolic conditions.   
     
     
         9 . The thermo-analytical instrument of  claim 1 , wherein:
 the thermo-analytical instrument is a differential scanning calorimeter.   
     
     
         10 . The thermo-analytical instrument of  claim 9 , wherein:
 the differential scanning calorimeter is a chip-type differential scanning calorimeter.   
     
     
         11 . The thermo-analytical instrument of  claim 1 , wherein:
 the heating means comprises a common heater associated with the sample position and the reference position.   
     
     
         12 . The thermo-analytical instrument of  claim 1 , wherein:
 the heating means comprises:
 a reference heater, associated with the reference position; and 
 a sample heater associated with the sample position. 
   
     
     
         13 . The thermo-analytical instrument of  claim 1 , further comprising:
 a common holder, on which is arranged both the sample position and the reference position.   
     
     
         14 . The thermo-analytical instrument of  claim 4 , further comprising:
 a common holder, on which is arranged both the sample position and the reference position.   
     
     
         15 . A method for controlling a thermo-analytical instrument that comprises a sample position for receiving a sample, a reference position, a heating means associated with the sample position and the reference position, a means for setting a predetermined temperature program of nominal values of temperature versus time, a first sensor for measuring a sample temperature at the sample position, a second sensor for measuring a reference temperature at the reference position, and a controller that controls the heating power of the heating means, the method comprising the steps of:
 placing a sample on the sample position;   applying the predetermined temperature program to the sample position and the reference position by controlling a heating power of the heating means and determining the sample temperature as a function of time, with the control of the heating power being controlled so as to cause the measured sample temperature to essentially follow the predetermined temperature program; and   deriving a net heat flow into the sample by measuring at least one of: the temperature at the sample position and a differential temperature arising between the sample position and the reference position.   
     
     
         16 . The method of  claim 15 , wherein:
 the thermal mass of the sample at the sample position is large relative to an imbalance of thermal mass between the reference position and the sample position.   
     
     
         17 . A differential scanning calorimeter for thermo-analytical analysis of a sample, comprising:
 a sample position for receiving the sample;   a reference position, the sample and reference positions being intrinsically symmetrical;   a means for heating, comprising a reference heater and a sample heater, associated with the corresponding reference and sample positions;   a means for setting a predetermined temperature program of nominal values of temperature versus time;   first and second sensors, the first sensor measuring a sample temperature at the sample position and the second sensor measuring a reference temperature at the reference position; and   a controller for controlling the heating power of the heating means so the measured sample temperature essentially follows the predetermined temperature program, with a differential in temperature between the sample temperature and the reference temperature representing a measurement signal.