Page 15
Notes on the MoSi heating elements
General
The air supply of the heating elements should be ensured, as the
heating elements need this oxygen supply for creating a quartz
protective layer. This protective layer has got the function to protect
the basic material from extreme oxidation and pollution.
The air supply should be realized by small openings at the furnace
inlet and outlet, so that there gets not too much power lost.
The heating elements should be able to radiate heat without
limitation.
Continuous
operation
The furnace is operated at its maximum temperature for a rather long
time (>10 h). To increase the life time of the heating elements it is
recommended for this kind of operation to cool down the furnace not
completely (T>650°C). If possible, never cool down to ambient
temperature.
Running times of up to 2,000-5,000 hours at high temperatures can
be realized.
Variable parameters must be chosen so that during continuous
operation there is no change of the correcting variables of more than
±10%.
Discontinuous
operation
Enables the cooling down to ambient temperature.
Daily heating ramps up to maximum temperature are possible.
However, the rest period should not be longer than 5 hours.
The life expectancy is about 100-300 heating cycles.
