Vacuum grease is a lubricant with low volatility and is used for applications in low pressure environments. Lubricants with higher volatility would evaporate, causing two problems:
- They would not be present to provide lubrication.
- They would make lowering the pressure below their vapor pressure difficult.
As well as a lubricant, vacuum grease is also used as a sealant for joints in vacuum systems. This is usually limited to soft vacuums, as ultra high vacuum or high temperatures may give problems with the grease outgassing. Grease is most commonly used with glass vacuum systems. All metal systems usually use knife-edge seals in soft metals instead. Where O ring seals are used, these should not be greased (in static seals at least) as it can cause the O rings to become permanently distorted when compressed.
In electronics manufacturing processes, vacuum grease is often used to prevent corrosion.
Famous quotes containing the word vacuum:
“When a daughter tries suicide
and the chimney falls down like a drunk
and the dog chews her tail off
and the kitchen blows up its shiny kettle
and the vacuum cleaner swallows its bag
and the toilet washes itself in tears ...”
—Anne Sexton (1928–1974)