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Vacuum Pumps

Vacuum Pumps. Basics. vac·u·um noun 1. a space entirely devoid of matter.

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Vacuum Pumps

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  1. Vacuum Pumps

  2. Basics • vac·u·um • noun 1. a space entirely devoid of matter. • 2. an enclosed space from which matter, especially air, has been partially removed so that the matter or gas remaining in the space exerts less pressure than the atmosphere ( opposed to plenum). (dictionary.com) • Exhaust pressure= atm generally • Base pressure = pressure pump gets down to • Compression ratio = exhaust/base= big number • Boyles Law P1V1=P2V2

  3. History of vacuum pumps • Suction pumps go way back (Romans, Byzantine empire, etc) • Major improvements on the idea of vacuum made by Galileo, Evangeilist Torricelli, and Blaise Pascal • Otto von Guericke made first pump and famous for Magdeburg hemispheres experiment

  4. Types of Vacuum pumps • Positive displacement pumps • Expand a cavity, seal, exhaust, repeat • Momentum transfer pumps (molecular pumps) • High speed liquids or blades to knock gasses around • Entrapment • Create solids or adsorbed gases (cryopumps)

  5. Roughing pumps • Pumps from atm pressure down to rough vacuum (0.1 Pa, 1X10-3torr) • Necessary because turbo pumps have trouble starting from atmospheric pressure • Usually Rotary Vane pumps • Can have oil or not

  6. Rotary vane pumps Oil Sealed Rotary Pumps Understanding Gas Ballastwww2.avs.org/chapters/nccavs/pdf/Gas_Ballast_OilSealedPumps.pdf

  7. Rotary vane pumps Condensation of vapor in the gas mixture is a problem with these pumps. Solution Ballasting Works by increasing the gas/vapor ratio (air is mostly gas) As you might imagine this interferes with the final vacuum

  8. Types • One stage or two stage • Belt Drive or direct drive Slower 400-600 RPM Bigger, Cheaper Faster 1500 to 1725 RPM Smaller, lighter

  9. Turbo (molecular) pumps • Gas molecules interact with spinning blades and are preferentially forced downward • High vacuum (10-6 Pa) requires rotation of 20,000 to 90,000 revolutions per minute • Generally work between 10-3 and 10-7 Torr • Ineffective before gas is in “molecular flow”

  10. Turbo (molecular) pumps • Options: • Bearings: Ceramic (oil lubricated) Magnetic (supported w/out physical contact), also hybrid • Rotor options (Blade configuration) • Cooling (air or water)

  11. Pump Care • Rough pumps shouldn’t need a lot of maintenance • If they do repair kits are available: • Minor kit includes all necessary seals (shaft seals, valves, o-rings, etc) • Major kit includes Minor Kit components plus vanes, springs, plugs, etc. • Seem to be available for most major brands and types • Turbopumps should need even less maintenance, bearings can wear out but must be replaced by manufacturer for balancing. http://www.sisweb.com/vacuum/sis/iseries-maintkit.htm

  12. Pump specs Spec sheet for an Edwards A65209903 RV rotary vane pump $3171

  13. Subset of specs for Edwards EXT 556H turbomolecular pump

  14. Rotary Vane: Pump speed lower at low vacuum Turbo pumps: opposite Pump Speed Pressure

  15. Useful fitting terminology • Flanges • Standard quick Release (QF, KF, NW, or DN) • Named based on internal diameter DN16KF is 16mm (16-50mm) • Large Quick releases (LF, LFB, MF or ISO) • Clamps or bolts (63-500mm) • Conflat (CF) used in ultra high vacuum settings, usually metal to metal seals • Sizing odd: Europe inner diamter in mm, NA outer diameter in inches

  16. Sizes we will likely find. www.vacuumresearchcorp.com/pdfs/valves/nwflanges06.pdf

  17. Pumps on the Delta S • Pumping system for Analyzer • Turbo molecular pump TPH 050 • Vacuum pump E2 M1, 52 • Differential Pumping system • Turbo molecular pump TPH 050 • Turbo molecular pump TPH 240 • Vorvakuumpumpe E2 M5, 50160 Hz

  18. Turbo molecular pump TPH 050 Turbo molecular pump TPH 240

  19. Units of pressure for your notes

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