Vacuum Pump Oil: The Circulatory System of the Vacuum Furnace

Just as vacuum pumps can be considered the heart of the vacuum furnace, so too can the oil be thought of as its circulatory system. The selection and properties of the oil are critical to proper furnace operation. Pump oil serves different purposes in different types of pumps, and even has different functions within the same pump. In addition to lubrication, it helps provide the seal on rotary vane and other wet pumps, and serves as the media to propel the pumped gas via kinetic action in diffusion pumps. Oil Formulations - Different pump oil formulations are specifically designed for different pump applications and careful consideration must be given to the oil selection. Typical motor oil, for example, is not sufficiently refined for use in a vacuum pump, has insufficient resistance to chemical attack, and contains additives that may be detrimental to the process being performed in the vacuum furnace. In addition, the viscosity must be considered. Lower viscosity oils are used for lower operating temperatures, and for smaller pumps, and medium viscosity oils are used for medium to large pumps. Temperature resistance is also critical, as many pumps operate at high temperatures, and the oil must be rated for these temperatures. Many of the oils used in vacuum pumps are not traditional oils at all, but made of silicone or other non-hydrocarbon fluids.