7008
Users Guide
8-4
8.1.10.3 Methanol
Methanol or methyl alcohol is often used at low temperatures below 0 °C.
Methanol is relatively inexpensive, has good control characteristics, and has a
low freeze point. Methanol is very toxic so care must be taken when using and
disposing of this fluid.
8.1.10.4 Mineral Oil
Mineral oil or paraffin oil is often used at moderate temperatures above the range
of water. Mineral oil is relatively inexpensive. At lower temperatures mineral oil is
quite viscous and control may be poor. At higher temperatures vapor emission
becomes significant. The vapors may be dangerous and use of a fume hood is
highly recommended. As with most oils mineral oil will expand as temperature
increases so be careful not to fill the bath too full that it over-flows when heated.
The viscosity and thermal characteristics of mineral oil is poorer than water so
temperature stability will not be as good. Mineral oil has very low electrical
conductivity. Use caution with mineral oil since it is flammable and may also
cause serious injury if inhaled or ingested.
8.1.10.5 Silicone oil
Silicone oils are available which offer a much wider operating temperature range
than mineral oil. These oils are more expensive as well. For information on
silicone oils contact Hart Scientific.
8.1.11 Fluid Characteristics Chart
Table 3 and Figure 6 have been created to provide help in selecting a heat ex-
change fluid media for your constant temperature bath. The charts provide both a
visual and numerical representation of most of the physical qualities important in
making a selection. The list is not all inclusive; many usable fluids may not have
been shown in this listing.
8.1.11.1 Limitations and Disclaimer
Every effort has gone into making these charts accurate; however, the data here
does not imply any guarantee of fitness of use for a particular application.
Working near the limits of a property such as the flash point or viscosity limit can
compromise safety or serviceability. Sources of information sometimes vary for
particular properties. Your company’s safety policies as well as personal
judgment regarding flash points, toxicity, etc. must also be considered. You are
responsible for reading the Material Safety Data Sheets and making a judgment
here. Cost may require some compromises as well. Hart Scientific cannot be
liable for the suitability of application or for any personal injury, damage to
equipment, product or facilities in using these fluids. The charts include
information on a variety of fluids which are often used as heat transfer fluid in
baths. Because of the temperature range some fluids may not be useful with your
bath.
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