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Low Temp Furnace Model ITL-M-17701 13-07/20
GENERAL NOTE ON ISOTECH METAL FREEZE POINT CELLS
Isotech freeze point cells contain metal that is 99.9999+% pure.
The metal is contained in crucibles of high-purity graphite. After machining the graphite, any residual metal
oxides are removed by exposure to fluorine at a very high temperature. Graphite, even of high density,
cannot be guaranteed to be non-microporous. Some cells, in preparation or after use, will be seen to
exude droplets or spicules of the contained metal on to the outer surface of the graphite crucible; some
may show a film of metal. This is considered not to be a defect of the cell; it does not reduce its useful life
nor change its equilibrium plateau temperature.
The cell is a fragile device. Although it is as rugged as is consistent with its materials and purpose, it must
still be regarded as a kilogram, or more, of mass, loosely contained in a frangible shell. Cells should never
be inverted, although they may be slowly turned to the horizontal and laid on their sides. Transporting cells
by common carrier is not recommended and, as furnished, they must be hand-carried. A broken cell
cannot, in general, be repaired, although a cell which is broken but sufficiently intact to contain its metal can
be used for some time if contamination is avoided.
Each cell can be supplied with an Inconel container or basket 400mm (16") in length, in which the cell
should be placed to facilitate removal from the furnace. The basket has two diametrically-opposite holes
near its upper end in which a wire handle of suitable material (for example, 14 SWG Nichrome) may be
temporarily attached. Once the cell is in the basket there may be no future need to remove it. It is urged
that the basket always be used with tin cells, because the recommended practice includes removal of the
cell from the furnace as part of the freeze cycle.
