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LNE

LNE. Center for Scientific and. Industrial Metrology (CMSI). Thermal & Optical Division. 29, avenue Roger. Hennequin. 78197. Trappes. , France. Temperature Fixed Points and Thermal Effects. G. Bonnier. georges.bonnier@lne.fr. (. ),. R. Morice, J.C. Barbaras. , N. Fleurence. ,.

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LNE

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  1. LNE Center for Scientific and Industrial Metrology (CMSI) Thermal & Optical Division 29, avenue Roger Hennequin 78197 Trappes , France Temperature Fixed Points and Thermal Effects G. Bonnier georges.bonnier@lne.fr ( ), R. Morice, J.C. Barbaras , N. Fleurence , V. Le Sant , P. Ridoux , J.R. Filtz

  2. Within the frame of the EUROMET project 732, LNE have shared its activity in two parts : • LNE-INM (Saint-Denis) realizes new cells and take in consideration the effects of impurities • LNE-CMSI (Trappes is concerned with the thermal environment set up to realize the fixed point. • The present paper deals uniquely with the point 2

  3. Component of uncertainty linked with heat exchanges with the surrounding can be large

  4. In association with a permanent heating process, a customary metal temperature fixed point is designed for : • Maintaining an enclosure at a stable temperature • Realizing uniform temperature enclosure • Affecting a known temperature value

  5. Schematic representation of melting and freezing process

  6. Aluminium Freezing UME Cell

  7. Aluminium Freezing UME Cell

  8. Al Freeezing Point Plateau Tx-Txbottom ; f= 0,08 Tx-Txbottom ; f= 0,14 Tx-Txbottom ; f= 0,25 Tx-Txbottom ; f= 0,40 Tx-Txbottom ; f= 0,55 Tx-Txbottom ; f= 0,63 Tx-Txbottom ; f= 0,70 Results obtained by my Mai-Huong Vallin at LNE-INM Hydrostatic pressure effect Results obtained by my Mai-Huong Vallin at LNE-INM

  9. Thermometer Where is located the liquid/solid interface ? Indium cell Indium guard Thermocouple Air pulsed furnace Heat flux sensor Heaters

  10. Temperature fixed point Design of a sealed cell

  11. Percentage of remaining liquid 100% 80% 60% 50% 40% 30% 15% 0%

  12. Melting process Percentage of liquid formed increases

  13. Materialization of a temperature fixed point • Freezing /melting and permanent heating • Both freezing and melting are a function of time • Effect of impurities • Thermal effects • Phase transition observed through calorimetric process • The result is, in principle, independent of time

  14. Schematic representation of a melt observed in a cryogenic sealed triple-point cell

  15. Cryogenic sealed cell placed in adiabatic calorimeter

  16. Multicells Hydrogen (13,8033 K) Deuterium (18,724 K) Neon (24,5561 K) Oxygen (54,3584 K) Nitrogen (63,151 K) Nitrogen (83, 8058 K) Carbon Dioxide (216, 592 K) mercury (234,3156 K) Water (273,16 K)

  17. Realisation of the Silver point using a calorimetric method Simplified scheme : 1, Silver cell 2, thermal insulating material 3, positioning system 4, ceramic tube 5, radiation shields 6, heat pipe 7,cell-holding system 8, heater

  18. Principle of the adiabatic method used at LNE to realize ITS-90 metal fixed points Heater Heater

  19. Thermometer Liquid Phase Solid Phase Temperature Distance Temperature profile in the cell during heating time

  20. Aluminium freezing point, constant heat flux method

  21. Aluminium freezing point. Calorimetric method

  22. Thermometer Design of the guard cell Indium cell Indium guard Thermocouple Air pulsed furnace Heat flux sensor Heaters

  23. In summary: • The principle of using the calorimetric method at any metal fixed point is established. • The actual design has to be improved in order to get a final design. • The final design must be easy to use. • Using calorimetric method induces a better definition of a fixed point temperature.

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