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BASIC VACUUM PRACTICE

BASIC VACUUM PRACTICE. To move a particle in a (straight) line over a large distance. Why is a Vacuum Needed?. (Page 5 manual). To provide a clean surface. Why is a Vacuum Needed?. (High)Vacuum. Atmosphere. Contamination (usually water). Clean surface. HOW DO WE CREATE A VACUUM?.

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BASIC VACUUM PRACTICE

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  1. BASIC VACUUMPRACTICE

  2. To move a particle in a (straight) line over a large distance Why is a Vacuum Needed? (Page 5 manual)

  3. To provide a clean surface Why is a Vacuum Needed? (High)Vacuum Atmosphere Contamination (usually water) Clean surface

  4. HOW DO WE CREATE A VACUUM?

  5. VACUUM PUMPS (METHODS) Gas Transfer Vacuum Pump Entrapment Vacuum Pump Kinetic Vacuum Pump Adsorption Pump Positive Displacement Vacuum Pump Drag Pump Rotary Pump Fluid Entrainment Pump Ion Transfer Pump Reciprocating Displacement Pump Cold Trap Ejector Pump Bulk Getter Pump Getter Pump Gaseous Ring Pump Diaphragm Pump Liquid Ring Pump Turbine Pump Liquid Jet Pump Diffusion Pump Getter Ion Pump Sublimation Pump Piston Pump Rotary Piston Pump Gas Jet Pump Diffusion Ejector Pump Self Purifying Diffusion Pump Axial Flow Pump Evaporation Ion Pump Multiple Vane Rotary Pump Sliding Vane Rotary Pump Vapor Jet Pump Fractionating Diffusion Pump Radial Flow Pump Sputter Ion Pump Rotary Plunger Pump Molecular Drag Pump Dry Pump Roots Pump Cryopump Turbomolecular Pump Condenser VACUUM PUMPING METHODS

  6. BAROMETER Mercury: 13.58 times heavier than water: Column is 13.58 x shorter : 10321 mm/13.58=760 mm (= 760 Torr) 10.321 mm 29,9 in 760 mm WATER MERCURY (Page 12 manual)

  7. PRESSURE OF 1 STANDARD ATMOSPHERE: 760 TORR, 1013 mbar AT SEA LEVEL, 0O C AND 45O LATITUDE

  8. Atmospheric Pressure (Standard) = gauge pressure (psig) pounds per square inch (psia) inches of mercury millimeter of mercury torr millitorr or microns pascal bar millibar 0 14.7 29.9 760 760 760,000 101,325 1.013 1013 Pressure Equivalents

  9. PARTIAL PRESSURES OF GASES CORRESPOND TO THEIR RELATIVE VOLUMES PARTIAL PRESSURE PERCENT BY VOLUME GAS SYMBOL PASCAL TORR N2 O2 A CO2 Ne He Kr H2 X H2O 78 21 0.93 0.03 0.0018 0.0005 0.0001 0.00005 0.0000087 Variable 593 158 7.1 0.25 1.4 x 10-2 4.0 x 10-3 8.7 x 10-4 4.0 x 10-4 6.6 x 10-5 5 to 50 79,000 21,000 940 33 1.8 5.3 x 10-1 1.1 x 10-1 5.1 x 10-2 8.7 x 10-3 665 to 6650 Nitrogen Oxygen Argon Carbon Dioxide Neon Helium Krypton Hydrogen Xenon Water THE ATMOSPHERE IS A MIXTURE OF GASES (Page 13 manual)

  10. P (mbar) 1013 32 6.4 0.13 6.6 x 10 -4 10 -24 T (O C) 100 25 0 -40 -78.5 -196 (BOILING) (FREEZING) (DRY ICE) (LIQUID NITROGEN) VAPOR PRESSURE OF WATER AT VARIOUS TEMPERATURES (Page 14 manual)

  11. (Page 15 manual)

  12. Vapor Pressure of some Solids (Page 15 manual)

  13. PRESSURE RANGES RANGE ROUGH (LOW) VACUUM HIGH VACUUM ULTRA HIGH VACUUM PRESSURE 759 TO 1 x 10 -3 (mbar) 1 x 10 -3 TO 1 x 10 -8 (mbar) LESS THAN 1 x 10 -8 (mbar) (Page 17 manual)

  14. GAS FLOWCONDUCTANCE (Page 24 manual)

  15. Viscous Flow (momentum transfer between molecules) Molecular Flow (molecules move independently) Viscous and Molecular Flow

  16. FLOW REGIMES Viscous Flow: Distance between molecules is small; collisions between molecules dominate; flow through momentum transfer; generally P greater than 0.1 mbar Transition Flow: Region between viscous and molecular flow Molecular Flow: Distance between molecules is large; collisions between molecules and wall dominate; flow through random motion; generally P smaller than 10 mbar -3 (Page 25 manual)

  17. 1013 mbar (atm) 1 x 10-3 mbar 1 x 10-9 mbar # mol/cm3 3 x 10 19 4 x 10 13 4 x 10 7 (30 million trillion) (40 trillion) (40 million) 2 inches 5.1 cm 2.5 x 10-6 in 6.4 x 10-5 mm 31 miles 50 km MFP MEAN FREE PATH MOLECULAR DENSITY AND MEAN FREE PATH

  18. Mean Free Path Characteristic Dimension is less than 0.01 Viscous Flow: Mean Free Path Characteristic Dimension is between 0.01 and 1 Transition Flow: Mean Free Path Characteristic Dimension is greater than 1 Molecular Flow: FLOW REGIMES

  19. Conductance in Viscous Flow Under viscous flow conditions doubling the pipe diameter increases the conductance sixteen times. The conductance is INVERSELY related to the pipe length (Page 28 manual)

  20. Conductance in Molecular Flow Under molecular flow conditions doubling the pipe diameter increases the conductance eight times. The conductance is INVERSELY related to the pipe length.

  21. Series Conductance RT = R1 + R2 SYSTEM 1 = 1 + 1 C2 CT C1 C1 1 = C1 + C2 CT C2 C1 x C2 CT = C1 x C2 C1 + C2 PUMP (Page 29 manual)

  22. GAS LOAD Permeation Outgassing Real Leaks Virtual Diffusion Backstreaming GAS LOAD (Q) IS EXPRESSED IN: mbar liters per second

  23. Pumpdown Curve 10+1 10-1 Volume 10-3 10-5 Surface Desorption Pressure (mbar) 10-7 Diffusion 10-9 Permeation 10-11 10 1 10 7 10 11 10 3 10 5 10 13 10 15 10 17 10 9 Time (sec)

  24. Roughing Pumps 2 (Page 39 manual)

  25. VACUUM PUMPS (METHODS) Gas Transfer Vacuum Pump Drag Pump Fluid Entrainment Pump Ejector Pump Bulk Getter Pump Gaseous Ring Pump Getter Ion Pump Sublimation Pump Evaporation Ion Pump Fractionating Diffusion Pump Molecular Drag Pump Turbomolecular Pump Condenser VACUUM PUMPING METHODS Entrapment Vacuum Pump Kinetic Vacuum Pump Adsorption Pump Positive Displacement Vacuum Pump Rotary Pump Ion Transfer Pump Reciprocating Displacement Pump Cold Trap Getter Pump Diaphragm Pump Liquid Ring Pump Turbine Pump Liquid Jet Pump Diffusion Pump Piston Pump Rotary Piston Pump Gas Jet Pump Diffusion Ejector Pump Self Purifying Diffusion Pump Axial Flow Pump Multiple Vane Rotary Pump Sliding Vane Rotary Pump Vapor Jet Pump Radial Flow Pump Sputter Ion Pump Rotary Plunger Pump Dry Pump Roots Pump Cryopump

  26. Rotary Vane Mechanical Pump Rotary Piston Mechanical Pump Dry Mechanical Pump Sorption Pump Blower/Booster Pump Venturi Pump PUMP OPERATING RANGES Ultra High Vacuum Rough Vacuum High Vacuum High Vac. Pumps Ultra-High Vac. Pumps 10-12 10-6 10-2 10-10 10-8 1 10+2 10-4 P (mbar)

  27. Chamber High Vac. Pump Roughing Pump Foreline Pump Hi-Vac. Valve Roughing Valve Foreline Valve Vent Valve Roughing Gauge High Vac. Gauge 1 2 3 3a 4 5 6 7 8 9 VACUUM SYSTEM USE 9 8 1 7 8 5 4 7 2 6 3 3a (Page 44 manual)

  28. Rotary Vane, Oil-Sealed Mechanical Pump (Page 45 manual)

  29. Pump Mechanism

  30. How the Pump Works (Page 46 manual)

  31. 2 OIL BACKSTREAMING PRESSURE LEVELS: LESS THAN 0.2 mbar

  32. The Molecular Sieve/Zeolite Trap (Page 48 manual)

  33. Dry Vacuum Pumps

  34. Blower/Booster Pump (Page 61 manual)

  35. One Stage Roots Blower Pump Assembly

  36. Chamber Foreline Roughing Valve Roughing Gauge Roughing Pump Foreline Foreline Valve Foreline Gauge High Vacuum Valve Booster/Blower Vent Valve High Vacuum Gauge 1 2 3 4 5 6 7 8 9 10 11 12 12 11 1 4 3 2 9 10 7 6 8 5 VACUUM SYSTEM USE (Page 62 manual)

  37. Sorption Pump Components (Page 54 manual)

  38. Vapor Pressure (Page 56 manual)

  39. Cryo-condensation

  40. Cryo-sorption (Page 55 manual)

  41. HIGH VACUUM PUMPS 3 (Page 63 manual)

  42. VACUUM PUMPS (METHODS) Gas Transfer Vacuum Pump Drag Pump Fluid Entrainment Pump Ejector Pump Bulk Getter Pump Getter Ion Pump Sublimation Pump Evaporation Ion Pump Fractionating Diffusion Pump Molecular Drag Pump Turbomolecular Pump Condenser VACUUM PUMPING METHODS Entrapment Vacuum Pump Kinetic Vacuum Pump Adsorption Pump Positive Displacement Vacuum Pump Rotary Pump Ion Transfer Pump Reciprocating Displacement Pump Cold Trap Getter Pump Gaseous Ring Pump Diaphragm Pump Liquid Ring Pump Turbine Pump Liquid Jet Pump Diffusion Pump Piston Pump Rotary Piston Pump Gas Jet Pump Diffusion Ejector Pump Self Purifying Diffusion Pump Axial Flow Pump Multiple Vane Rotary Pump Sliding Vane Rotary Pump Vapor Jet Pump Radial Flow Pump Sputter Ion Pump Rotary Plunger Pump Dry Pump Roots Pump Cryopump

  43. PUMP OPERATING RANGES Ultra High Vacuum Rough Vacuum High Vacuum Roughing Pumps Liquid Nitrogen Trap Diffusion Pump Turbo Pump Cryo Pump Ion Pump Tit. Subl. Pump 10-12 10-6 10-2 10-10 10-8 1 10+2 10-4 P (Torr)

  44. Chamber High Vac. Pump Roughing Pump Fore Pump Hi-Vac. Valve Roughing Valve Foreline Valve Vent Valve Roughing Gauge High Vac. Gauge 1 2 3 3a 4 5 6 7 8 9 VACUUM SYSTEM USE 9 8 1 7 8 5 4 8 2 2 6 3 3a

  45. Oil Diffusion Pump

  46. Pump Construction (Page 66 manual)

  47. How the Pump Works

  48. How the Pump Works

  49. First stage vapors are separated from others

  50. 1 2 3 4 Critical Point Pumping Speed (Air) 1. Compression Ratio Limit 2. Constant Speed 3. Constant Q (Overload) 4. Mechanical Pump Effect 10-10 10--3 10--1 Inlet Pressure (Torr) Pumping Speed

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