Cannon Instrument CT-2000 (Contant Temperature Bath) - Manual (Page 36)

CANNON ® CT-2000 Constant Temperature Bath
Revision 1.0g—February, 2012; CANNON ® Instrument Company
2139 High Tech Road • State College, PA 16803 • USA
34
IBF Bath Oil IBF Bath Oil contains an oxidation inhibitor which reduces tendency to
darken at higher temperatures. Viscosity is 36 cSt at 40°C, 5.6 cSt at
100°C. This oil is available from CANNON
® (catalogue # 9726-L20).
Silicone fluids
Silicone fluids are available in a wide range of viscosities and can be
used over a wide range of temperatures. However, silicones are also
relatively expensive liquids. Also, 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.