LNE

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
georges.bonnier_at_lne.fr
G. Bonnier
(
),
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
(No Transcript)
9
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
10
Thermometer
Where is located the liquid/solid interface ?
Indium cell
Indium guard
Thermocouple
Air
pulsed
furnace
Heat flux
sensor
Heaters
11
Temperature fixed point Design of a sealed cell
12
Percentage of remaining liquid
100 80 60
50 40
30 15 0
13
(No Transcript)
14
(No Transcript)
15

• 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

16
Schematic representation of a melt observed in a
cryogenic sealed triple-point cell
17
Cryogenic sealed cell placed in adiabatic
calorimeter
18
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)
19
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
20
Principle of the adiabatic method used at LNE to
realize ITS-90 metal fixed points
Heater
Heater
21
(No Transcript)
22
Temperature profile in the cell during heating
time
23
Aluminium freezing point, constant heat flux
method
24
Aluminium freezing point. Calorimetric method
25
Thermometer
Design of the guard cell
Indium cell
Indium guard
Thermocouple
Air
pulsed
furnace
Heat flux
sensor
Heaters
26

• 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.