Cannon Instrument CT-600 (Contant Temperature Bath) - Manual (Page 30)

28
CANNON CANNON CANNON CANNON CANNON ® CT-500/600 Series II CONSTANT TEMPERATURE BATH
Version 3..3—March, 2012; CANNON CANNON CANNON CANNON CANNON ® Instrument Company
2139 High Tech Road • State College, PA • 16803 • USA
Water
Water is almost the ideal fluid in the temperature range in which it can be
used. Due to the possibility of algae formation, some type 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 uncom-
fortable. It may be difficult to establish optimum temperature stability 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 oil's
useful life, but the oil will eventually become as dark as untreated oil.
The search for more suitable bath oils is unending. Hydrogenated
vegetable oils, coconut oil, synthetic oils, and certain chemical com-
pounds have been used with some success at various temperatures.