6.0 Operation
Operators are advised to periodically check the thermocouple output, either by a
calibration test or by comparing the output with a new reference thermocouple which
has been subjected to high temperatures for a minimum length of time.
Failure to check the thermocouple regularly may result in overheating of the work and
the furnace, with consequential damage to both.
(2) The thermocouples fitted to these models give very low outputs below
approximately 600 °C and do not give accurate readings at low temperatures. They
may show a negative temperature when the furnace is started from cold.
This furnace is not intended to operate with a setpoint below 600 °C.
6.9
Inverted Crucible Option
Take special care over safety considerations: ensure that there is a safe surface on
which to place the crucible when hot. If the process permits, avoid lowering the hearth
when the chamber is hot.
Depending on the height of the work-piece, it may be necessary to hold the crucible up
in the chamber when placing the work-piece on the hearth; ensure that appropriate
tongs are available before starting.
Clamp Option
This option assists the placing of the crucible over tall work-pieces. The “clamp” is
provided in the form of a support shelf which can be fitted to a hinge on the case and a
pair of insulated tongs.
With the hearth lowered, place the support shelf on the hinge and swing to the side. Use
the tongs to lift the crucible up into the chamber, swing the shelf to the centre and lower
the crucible.
Place the work-piece. Reverse the procedure above and carefully lower the crucible over
the work-piece. Remove the shelf before raising the hearth.
6.10
Element Protection Tube Option
For application where the material being heated may give off fumes or splash, an
inverted crucible can be fitted to protect the elements that is permanently located in the
furnace body.
The tubes utilised for element protection within the BLF range of furnaces are fragile
and extreme care should be taken when handling them.
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