where high vacuum grease is used ?

Answer 1

High vacuume greases are required when there is a chance of air ingrace/any impurities which hampered the vacuume stability like in compressors for o rings sealing,if otherwise system will be pressurised and becomes unsafe and also the capacity loss will be there.

The high vacuume grease finds wide application for the lubrication of water-treating equipment and general laboratory equipment even for non-vacuum applications. It is used for the lubrication of "o" rings on binoculars and telescopes, and is also used to prevent fogging on delicate lenses and mirrors.
High-Vacuum Greaseresists vegetable and mineral oils andcommon gases. It also resists aqueous solutions of inorganic salts and dilute acids and alkalis.
High-Vacuum Grease isrecommended for vacuums reaching between 1 x 10^-5 and 1 x 10^-6 mm Hg. It is recommended that the grease be pre-conditioned under vacuum and temperature until these limits are reached. For details on attaining higher vacuums,
http://209.85.165.104/search?q=cache:9kg7RX-Z_lsJ:www.duniway.com/images/pdf/pg/DC-150-datasheet.pdf+high+vacuum+grease&hl=en&ct=clnk&cd=5&gl=uk

Answer 2

I've used it to grease o-rings on electrical connectors penetrating vacuum-chamber bulkheads. I've also used it on the seals to vacuum-chamber doors.

(We test electronic equipment inside vacuum-chambers.)

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