Vacuum greases and vacuum pump oils are suitable for vacuum sealing, diffusion pumps and other vacuum fluid applications. Typically, vacuum greases and vacuum pump oils are used with vacuum pumps or generators, which remove air from a system to create a pressure differential. Some vacuum greases and vacuum pump oils are USDA food plant approved, which means that the grease or oil is approved for incidental food contact in federally inspected meat and poultry plants according to regulations from the U.S. Department of Agriculture (USDA). Vacuum oil can also be used with high-vacuum pumps to trap and contain contaminants and impurities in the air during evacuation. Because the buildup of water and contaminants can prevent a vacuum pump from reaching its ultimate vacuum capacity, manufacturers of vacuum greases and vacuum pump oils recommend checking greases and oils on a periodic basis.
Vacuum greases and vacuum pump oils are related, but different products. Vacuum grease is silicone-based and used as a sealant in vacuum and pressure systems. Vacuum greases have low volatility and is highly resistant to water, alkalis, and chemicals. Vacuum pump oil is low vapor pressure oil used in a vacuum diffusion pumps to capture molecules, which are continuously removed by the fore pump to create a usable vacuum. Diffusion pump oil is a polyphenylether liquid used in diffusion pumps to provide thermal stability, low pressure, and low back streaming. Because of the low back streaming rates in diffusion pumps, vacuum greases and vacuum pump oils may make the use of traps and baffles unnecessary.
Vacuum greases and vacuum pump oils are made of perflourinated polyether, silicone, polyphenyl, dioctylsebacate, or hydrocarbon fluids. Standard vacuum pump fluids are suitable for normal operating conditions. In corrosive environments, the selection of high-viscosity silicone grease may be necessary. Mechanical vacuum pump fluids are engineered to maintain optimum lubrication while achieving the lowest possible vacuum level. These corrosion resistant products are commonly available.