Dowtherm

Dowtherm is a brand of high-temperature heat transfer fluids developed by Dow Chemical (now Dow Inc.). The fluid family is designed for closed-loop heating and cooling in industrial process equipment, providing high boiling points, low vapor pressures, and superior thermal stability at elevated temperatures. Several formulations are marketed under the Dowtherm name, including Dowtherm A and Dowtherm Q. These fluids are based on aromatic hydrocarbons and related compounds and are selected for long service life, good heat transfer, and compatibility with common metals and system components. Dowtherm A variants are used for heating and jacketed processes where high temperature operation is required, while Dowtherm Q-type fluids may be formulated for different temperature ranges and chemical resistance.

Properties of Dowtherm fluids include high thermal stability relative to mineral oil-based fluids, low volatility at operating temperatures, and favorable heat transfer characteristics. They typically have moderate to low viscosities that facilitate pumping and efficient heat exchange. They are designed to withstand repeated thermal cycling and to resist premature degradation; however, exposure to air, high temperatures, or contamination can lead to degradation and formation of insoluble residues.

Uses and applications encompass chemical processing, petrochemical plants, plastics manufacturing, and other industries requiring reliable heat transfer in reactors, distillation columns, and process heat exchangers. Safety considerations categorize Dowtherm fluids as flammable; they should be handled with appropriate precautions, using closed systems, ignition-source control, and proper storage. Regular maintenance and compatibility checks are advised to minimize oxidation and accumulation of decomposition products.

See also: Heat transfer fluid, Therminol.