Mobiltherm 603, is a high performance product intended for use in closed indirect heating installations. It is formulated from highly refined base stocks that are resistant to thermal cracking and chemical oxidation. They have good heat transfer efficiency and their viscosities are such that they can be pumped readily at both start-up and operating temperatures. The flash points of these oils will not decrease significantly in service because of their resistance to thermal cracking at the operating temperatures for which they are recommended. The Mobiltherm products are very thermally stable and are capable of an extremely long service life without deposit formation or viscosity increase. It also has the following benefits:
High resistance to thermal cracking and decomposition:Freedom from sludge and coke deposits and minimum interference with heat transfer capability and minimised maintenance needsExcellent thermal properties:High heat transfer rates and improved operating efficiency and lower operating costsGood thermal and oxidative stabilityLong trouble free service life and reduced downtimeGood low temperature fluidity:Easy starting of cold systems
Mobiltherm 603 heat transfer oil should not be mixed with other oils since this may impair the excellent thermal and oxidation stability of Mobiltherm 603 heat transfer oil, cause a change in other properties, and complicate the interpretation of analyses made to determine the oil's useful life. If the oils are used above their recommended maximum temperatures, vapor lock may result unless the system is designed to operate at the higher temperature by pressurising with an inert gas such as nitrogen. However, at higher temperatures, fluid life will be shortened because the rate of thermal degradation increases markedly as temperatures rise above the recommended limit. In well-designed systems the temperature of the oil film surrounding the heating element should be about 15C to 30C above the bulk oil temperature. If higher than this, the service life of the oil may be shortened and sludge and coke may be deposited which would interfere with the heat transfer rates. As with other mineral oils, Mobiltherm 603 heat transfer oil should be used only in systems with forced circulation. Systems that depend on convection for circulation of the heat transfer medium do not provide a rapid enough flow to prevent local overheating and rapid deterioration of the oil. Further, this oil is not recommended for use in open systems where hot oil is exposed directly to the air. If it sprays or escapes from leakage points, hot Mobiltherm 603 heat transfer oil may spontaneously ignite. Mobiltherm 603 heat transfer oil can be used in open and closed installations where the bulk oil temperature ranges are as outlined in the table below and where minimum shutdown temperatures are not below -12C.