Gelest, Inc. offers a number of silicone heat transfer fluids for five basic applications:
Heat treatment baths, constant temperature baths, temperature measurement devices, closed loop heating, and refrigerated systems. Four different classes of silicone fluids -thermal, conventional, fluorosilicone, and low temperature – are used in these five applications.
Thermal silicone fluids are used in heating baths, constant temperature baths, temperature measurement devices, and closed loop systems. They are described as aromatic siloxanes. The phenyl groups enhance oxidation resistance, thermal stability, and shear resistance. The phenyl groups offer better protection of the chain Si-O-Si-O by steric hindrance and phenyl itself has a low susceptibility to oxidative attack. The service temperature ranges from -55ºC to 290ºC for high phenyl content silicone fluids. The polyphenylmethylsiloxanes are stable for thousands of hours at 250ºC in closed oxygen free systems.
Thermal Silicone Fluids
Conventional Silicone Fluids
Conventional (intermediate viscosity) silicone fluids are used in constant temperature baths and temperature measurement devices. The conventional silicone fluids are composed of polymer chains with unique flexibility. These fluids are indefinitely stable at 150ºC in air, and the vapor pressure becomes negligible at viscosities of 50 cSt.
Fluorosilicone Fluids
Fluorosilicone fluids are used in temperature measurement devices. The fluids are useful in temperatures from -40ºC to 230ºC and have unique applications due to their chemical and solvent resistance to lubricity.
FMS-221
(48-52% TRIFLUOROPROPYLMETHYLSILOXANE) (48-52% DIMETHYLSILOXANE) COPOLYMER, 80-120 cSt
Low Temperature Fluids
Low temperature silicone fluids are used in refrigerated systems. Polydiethylsiloxanes are oxidatively stable to 150ºC and thermally stable under inert atmospheres to 225ºC. Branched and low viscosity fluids offer higher purity levels, discrete vapor pressures, and more linear rheology as a function of pressure and temperature.
