Cannon Instrument CT-1000 (Contant Temperature Bath) User Manual
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CANNON
®
CT-1000 Constant Temperature Bath Instruction & Operation Manual
Revision 3.1e—June, 2011;
CANNON
®
Instrument Company
2139 High Tech Road • State College, PA • USA 16803
Isopropyl alcohol
Isopropyl alcohol is less toxic than methyl alcohol and somewhat less
volatile. However, it becomes very viscous at low temperatures and is
therefore unsuitable for use at very low temperatures.
Silicone fluids
Silicone fluids are available in a wide range of viscosities and can be
used over a wide range of temperatures if the proper selection of viscos-
ity is made for the temperature range of interest. Silicones are also
relatively expensive liquids. However, a bath containing silicones
requires extra care when used for capillary viscometry. If silicones are
introduced into a viscometer capillary, its calibration factor will be
altered by a significant amount.
Water
Water is almost the ideal fluid in the temperature range in which it can be
used. Because in some cases there is a tendency for algae formation,
some degree of water treatment may be necessary. Water can be used at
temperatures close to the boiling point, but water replenishment to offset
evaporation becomes a nuisance and the hot vapor can make working
above the bath uncomfortable. Also, it may be difficult to establish
optimum control at elevated temperatures because of the rapid cooling
resulting from surface evaporation.
Refined white oils
Refined white oils (paraffin oils) of relatively low viscosity can be used
at temperatures above the level at which water becomes unsatisfactory.
Because these oils will turn faintly yellow and continue to darken with
prolonged exposure to heat, we recommend adding an oxidation inhibitor
to retard discoloration. The addition of an inhibitor will prolong the
useful life of the oil, but it will eventually become as dark as untreated
oil.
The search for more suitable bath oils is unending. Hydrogenated veg-
etable oils, coconut oil, synthetic oils, and certain chemical compounds
have been used with some success at various temperatures.