ELTRA CS-2000, Manual

Page: 82 / 110

Function description
82
7.5 Furnace
7.5.1 Induction furnace
The combustion is carried out in a high frequency induction furnace. The sample is inserted into
the induction coil of the oscillating circuit of the pedestal, then heated by high frequency
induction and combusted by supplying oxygen.
By starting the analysis, the HF generator's high voltage supply is switched on. Inside the coil, a
quartz tube is fitted to an upper and a lower holder. The gas flows downwards. The furnace inlet
leads through a lance, which blows the oxygen for combustion directly into the crucible and onto
the burning sample. When the sample is inserted into the furnace by the pedestal, the lower
opening of the quartz tube is closed with the sealing cone.
Fig. 53: Automatic induction furnace cleaning
The users of carbon and sulfur analyzers with induction furnaces know that dust accumulates
during the combustion (mainly of iron and tungsten oxides) in the combustion chamber.
The CS-2000 induction furnace is cleaned automatically after each analysis, thus ensuring
repeatable and accurate results. The cleaning mechanism is mechanically attached to the
furnace open/close system, to ensure that the cleaning brush will not collide with the hot
crucible.The cleaning brush will never burn. The efficient design of the cleaning mechanism
rules out any possibility of the cleaning brush to burn.
–
After each analysis start, a thyristor switches on the high voltage transformer "smoothly",
to prevent any current surge in the mains power supply and therefore eliminating the risk
of blowing any fuses.
–
The induction coil is cooled internally with compressed air. The outside is cooled by a
blower, which also ventilates the generator.
– The induction furnace uses standard ceramic crucibles, which are 1“ resp. 25 mm in
diameter.