Vortrag Hightemp Furnaces

German-Japanese Joint Symposium, Freiberg, 20. - 21. July 2015

Volker Uhlig, Hendrik Richter and Uwe Lohse:

High temperature furnaces made from graphite materials

Dr. Volker Uhlig

TU Bergakademie Freiberg

Institute of Thermal Engineering

Gustav-Zeuner-Straße 7

D-09599 Freiberg

Dr. Uwe Lohse, Dr. Hendrik Richter

XERION Ofentechnik GmbH Freiberg

Halsbrücker Straße 34

D-09599 Freiberg

2 TU Bergakademie Freiberg I Institut für Wärmetechnik und Thermodynamik | Lehrstuhl für Gas- und Wärmetechnische Anlagen I Gustav-Zeuner-Str. 7

09596 Freiberg I Telefonnummer: 03731 / 39-2177 I www.tu-freiberg.de I Dr.-Ing. Volker Uhlig I German-Japanese Symposium

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Outline

1. Vacuum in graphite furnaces

2. Design of resistance heaters

3. Furnaces for special applications



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1. Vacuum in graphite furnaces



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Temperatures: up to 2000 °C

Atmosphere: N2, Ar, H2

Pressure: 10-3 mbar to1000 mbar

Vacuum: Analysis of residual gas by

quadrupole mass spectrometer

Graphite furnaces for vacuum and protective gases -

analysis of (residual) gas



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Vacuum furnaces - analysis of residual gas

Results



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Analysis of residual gas - applications

• Degassing behavior of (new) materials

• Testing of furnaces (air leakage, water leakage)

• Testing of gas supply systems

• Process quality

• Materials research



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Analysis of residual gas - applications

Degassing behavior of materials



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Comparison of results in residual gas analysis

Partial pressure from 1 to 100 amu

Comparison of the spectra:

- Identical temperature time cycle

- Difference between two measurements of partial pressure

- Scaling to valur of reference cylce

pi - Partial pressure of molecular mass i

x - Sample

0 - Empty furnace

Condition: Comparable pressure ranges!

)0(p

)0(p)x(pp

i

iii,rel



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Degassing of insulation material -

Hydrocarbon fragments C1…C3



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Degassing of insulation material

Cyclic hydrocarbons



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2. Design of resistance heaters



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Design of resistance heaters

Basics: Surface load: < 20 W/cm²

Current density: < 5 A/mm²



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Design of resistance heaters

3-phase short circuit ring Meander heater

Design similar, wiring scheme different equal quality of solution ?

XERION ADVANCED HEATING



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0,00

0,10

0,20

0,30

0,40

0,50

0,60

0 100 200 300 400

Voltage / V

Height of heater / mm

3 phase heater with short circuit ring




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Meander heater - power concentration in u-bends

Text

Version 1 Version 2

Version 4 Version 3

Equal thickness

Equal colour = equal power density




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Wiring scheme delta current

1,7 I

1 I

0,5 I




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3. Furnaces for special applications




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6 phase heater with short circuit ring




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Graphite furnace for

chemical vapour deposition processes XERION ADVANCED HEATING



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Multi-zone furnace with

carbon fiber reinforced carbon heaters




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Hot pressing furnace

Furnace integrated in a press frame

6 phase heating




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Graphite furnaces for high vacuum applications

Radiation shields: Carbon fiber reinforced carbon




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Split furnace for material testing




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Split furnace for material testing




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Split furnace for material testing XERION ADVANCED HEATING



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Thank you for your attention ! XERION ADVANCED HEATING

Vortrag Hightemp Furnaces

Documents

germanjapanese symposium

residual gas results

vacuum furnaces analysis

graphite materials

high temperature furnaces

behavior of materials

protective gases analysis

h2 pressure