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

2

Outline

1. Vacuum in graphite furnaces

2. Design of resistance heaters

3. Furnaces for special applications



3

1. Vacuum in graphite furnaces



4

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



5

Vacuum furnaces - analysis of residual gas

Results



6

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



7

Analysis of residual gas - applications

Degassing behavior of materials



8

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



9

Degassing of insulation material -

Hydrocarbon fragments C1…C3



10

Degassing of insulation material

Cyclic hydrocarbons



11

2. Design of resistance heaters



12

Design of resistance heaters

Basics: Surface load: < 20 W/cm²

Current density: < 5 A/mm²



13

Design of resistance heaters

3-phase short circuit ring Meander heater

Design similar, wiring scheme different equal quality of solution ?

XERION ADVANCED HEATING



14

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




15

Meander heater - power concentration in u-bends

Text

Version 1 Version 2

Version 4 Version 3

Equal thickness

Equal colour = equal power density




16

Wiring scheme delta current

1,7 I

1 I

0,5 I




17

3. Furnaces for special applications




18

6 phase heater with short circuit ring




19

Graphite furnace for

chemical vapour deposition processes XERION ADVANCED HEATING



20

Multi-zone furnace with

carbon fiber reinforced carbon heaters




21

Hot pressing furnace

Furnace integrated in a press frame

6 phase heating




22

Graphite furnaces for high vacuum applications

Radiation shields: Carbon fiber reinforced carbon




23

Split furnace for material testing




24

Split furnace for material testing




25

Split furnace for material testing XERION ADVANCED HEATING



26

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