Linn High Therm GmbH
HT-1500-GT-VAC-Spezial GRAPHITE
page
19
operating instruction issue 30.10.2018
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KF are provided. On demand it can be used for lead
– in off an extrusion die
(pressure force max. 60 kg). The insulation below the flange is provided with a
removable insulating plug d= 40 mm. The furnace bottom is reinforced by fibre light
bricks so that it can carry on 320 x 560 mm a weight of 100 kg or rather per 50 kg
floor loading could be beard on the area of each of both further ducts.
4.4 Oxygen measurement in the exhaust gas line
In the exhaust gas line a gas outlet is foreseen for the separate arrangable oxygen
measurement unit Zr-Ox MK II. On this the unit measures the oxygen content of the
exhaust gas. The measuring range goes from 1 ppm to 99,9 % O2. The display of
the oxygen content is effected also over the temperature programme controller. The
measurement device will be placed on the top control housing. By the separate
construction a fast change of the units for calibration is possible. The signal output to
the controller is 4-20mA (breakdown information).
4.5 Three zone heating
The heating is effected by 12 changeable graphite heating elements which are
operated by 3 three
– phase current thyristor units in phase angle control and 3 three
– phase current transformers. The heating element connections are brought out at
the side (zone 1 with 2 heaters, zone 2 with 8 heaters, zone 3 with 2 heaters).
Sidewise, approximately in the centre of each zone, a double thermocouple type
PtRhPt type S each measures the temperature per zone. A thermopair is lead to the
temperature controller and the second one is lead to the safety controller.
4.6 Maximum admissible element temperatures and vacuum
For protective gas operation the maximum admissible temperatures of the heating
elements made of graphite are listed in following table.
The maximum admissible temperature for the furnace chamber is approximately
50°C to 70°C lower than the corresponding value in the table, see also below
remark.
Reaction graphite / CFC with process gases
atmosphere
Start of reaction
reaction
Air
500 ~ 600 °C
Oxidation
Water vapour
700 ~ 750 °C
Oxidation
CO
2
800 ~ 900 °C
Oxidation
H
2
1000 ~ 1200 °C
Methanisation
N
2
2000 ~ 2500 °C
Cyanid - formation
Cl
2
2500 °C
evaporation
Ar
3000 °C
evaporation
vacuum
2200 °C
evaporation