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Basic Vacuum Aspects
The document discusses basic vacuum physics and technologies. It defines vacuum as a space containing gas at a pressure below atmospheric pressure. Vacuums are needed to provide clean surfaces and move particles over long distances. Different types of vacuums and vacuum pumps are described, along with their operating pressure ranges and applications in various industries. Key concepts covered include pressure measurements, gas flow regimes, mean free path, conductance, outgassing, and selecting the appropriate pump based on required pressure and volume.
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Basic Vacuum Aspects
- 1. Basic Vacuum Physics & Technologies MohdIrshad Alam Sales Engineer me_irshad@yahoo.com
- 2. What is aVacuum? • Ideal Vacuum – A space totally devoid of all matter. – Does not exist, even in outer space! • Actual Vacuum (Partial Vacuum) – A space containing gas at a pressure below the surrounding atmosphere or atmospheric pressure less than 760 Torr @ sea level and 00 C with no humidity
- 3. Why is aVacuum Needed? To move a particle in a (straight) line over a large distance (irshad_alam@aol.com)
- 4. Why is aVacuum Needed? Contamination (usually water) Clean surface Atmosphere (High)Vacuum To provide a clean surface
- 5. BAROMETER WATER MERCURY 760 mm Mercury: 13.58times heavier than water: Column is 13.58 x shorter : 10321 mm/13.58=760 mm (= 760 Torr) 10.321 mm 29,9 in (irshad_alam@aol.com)
- 6. PRESSURE OF 1STANDARD ATMOSPHERE: 760 TORR, 1013 mbar AT SEA LEVEL, 0O C AND 45O LATITUDE
- 7. Pressure Equivalents Atmospheric Pressure(Standard) = 0 14.7 29.9 760 760 760,000 101,325 1.013 1013 Gauge pressure (psig) Pounds per square inch (psia) Inches of mercury Millimeter of mercury Torr Millitorr or microns Pascal Bar Millibar
- 8. THE ATMOSPHERE ISA MIXTURE OF GASES PARTIAL PRESSURES OF GASES CORRESPOND TO THEIR RELATIVE VOLUMES GAS SYMBOL PERCENT BY VOLUME PARTIAL PRESSURE TORR PASCAL Nitrogen Oxygen Argon Carbon Dioxide Neon Helium Krypton Hydrogen Xenon Water 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 (irshad_alam@aol.com)
- 9. VAPOR PRESSURE OFWATER AT VARIOUS TEMPERATURES T (O C) 100 25 0 -40 -78.5 -196 P (mbar) 1013 32 6.4 0.13 6.6 x 10 -4 10 -24 (BOILING) (FREEZING) (DRY ICE) (LIQUID NITROGEN) (irshad_alam@aol.com)
- 10. 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) (irshad_alam@aol.com)
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- 12. Viscous and MolecularFlow Viscous Flow (momentum transfer between molecules) Molecular Flow (molecules move independently)
- 13. FLOW REGIMES Viscous Flow: Distancebetween 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 (irshad_alam@aol.com)
- 14. MEAN FREE PATH MOLECULARDENSITY AND MEAN FREE PATH 1013 mbar (atm) 1 x 10-3 mbar 1 x 10-9 mbar # mol/cm3 MFP 3 x 10 19 (30 million trillion) 4 x 10 13 (40 trillion) 4 x 10 7 (40 million) 2.5 x 10-6 in 6.4 x 10-5 mm 2 inches 5.1 cm 31 miles 50 km
- 15. FLOW REGIMES Mean FreePath Characteristic Dimension Viscous Flow: is less than 0.01 Mean Free Path Characteristic Dimension Molecular Flow: is greater than 1 Mean Free Path Characteristic Dimension Transition Flow: is between 0.01 and 1
- 16. Conductance in ViscousFlow Under viscous flow conditions doubling the pipe diameter increases the conductance sixteen times. The conductance is INVERSELY related to the pipe length (irshad_alam@aol.com)
- 17. Conductance in MolecularFlow Under molecular flow conditions doubling the pipe diameter increases the conductance eight times. The conductance is INVERSELY related to the pipe length.
- 18. SYSTEM PUMP C1 C2 Series Conductance RT =R1 + R2 1 = 1 + 1 C1 C2CT 1 = C1 + C2 C1 x C2CT CT = C1 x C2 C1 + C2 (irshad_alam@aol.com)
- 19. GAS LOAD Outgassing Leaks Virtual Real Backstreaming Diffusion Permeation GAS LOAD(Q) IS EXPRESSED IN: mbar liters per second
- 20. Pump down Curve Pressure(mbar) Time(sec) 10-11 10 1 10 3 10 5 10 7 10 9 10 11 10 13 10 15 10 17 10+1 10-1 10-3 10-5 10-7 10-9 Volume Surface Desorption Diffusion Permeation
- 21. HOW DO WECREATE A VACUUM?
- 22. VACUUM PUMPING METHODS SlidingVane Rotary Pump Molecular Drag Pump Turbomolecular Pump Fluid Entrainment Pump VACUUM PUMPS (METHODS) Reciprocating Displacement Pump Gas Transfer Vacuum Pump Drag Pump Entrapment Vacuum Pump Positive Displacement Vacuum Pump Kinetic Vacuum Pump Rotary Pump Diaphragm Pump Piston Pump Liquid Ring Pump Rotary Piston Pump Rotary Plunger Pump Roots Pump Multiple Vane Rotary Pump Dry Pump Adsorption Pump Cryopump Getter Pump Getter Ion Pump Sputter Ion Pump Evaporation Ion Pump Bulk Getter Pump Cold TrapIon Transfer Pump Gaseous Ring Pump Turbine Pump Axial Flow Pump Radial Flow Pump Ejector Pump Liquid Jet Pump Gas Jet Pump Vapor Jet Pump Diffusion Pump Diffusion Ejector Pump Self Purifying Diffusion Pump Fractionating Diffusion Pump Condenser Sublimation Pump
- 23. PUMP OPERATING RANGES 10-1210-10 10-8 10-6 10-4 10-2 1 10+2 P (mbar) Rough VacuumHigh VacuumUltra High Vacuum Venturi Pump Rotary Vane Mechanical Pump Rotary Piston Mechanical Pump Sorption Pump Dry Mechanical Pump Blower/Booster Pump High Vac. Pumps Ultra-High Vac. Pumps
- 24. ROTARY VANE TECHNOLOGY Principlesof Operation: A lubricated rotary vane pump has a series of sliding vanes attached to a rotor in the pump cylinder. As the rotor spins, centrifugal force causes the vanes to slide outward to form a seal on the cylinder wall with oil that is injected into the pumping chamber. Air is pulled in to the pump inlet which is then compressed and discharged into the exhaust box. The sealing oil is filtered and re-circulated within the pump via oil filters which eliminates 99.9% of lubricating oil from the exhaust. Benefits: Air cooled design Direct drive 29.3" Hg end vacuum Anti suck back valve Oil flooded for lubrication and heat dissipation
- 25. OIL LUBRICATED ROTARYVANE TECHNOLOGY
- 26. OIL SEALED ROTARYVANE TECHNOLOGY
- 27. How the PumpWorks at Double Stage (irshad_alam@aol.com)
- 28. Why Vacuum? Using vacuumsranks as one of the traditional interface technologies. Vacuums are used in industry and commerce for packaging, drying, suction and pick-and-place. Some process engineering operations are carried out in a vacuum because low pressure is an advantage on temperature-sensitive products.
- 29. How to selecta Vacuum Pump First, you have to create the vacuum: And this is where the vacuum pumps come in. However, it’s worth clearing up a few key questions right at the outset. What volume of what end-pressure needs to be achieved, and in what time? Are there application-specific parameters which need to be taken into account? And what compression principle is best suited for a specific application?
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- 31. Principles of Operation: Arotor is mounted eccentrically in the pump cylinder and contains several sliding vanes. As the rotor turns, centrifugal force causes the vanes to slide outward, creating a seal against the cylinder wall. The vanes are constructed of a self-lubricating graphite composite material which allows them to operate against the cylinder wall without the need for any other sealing or lubricating liquid. As a result of the offset rotor, a succession of variable volumes is formed in the cylinder housing creating the flow of vapor through the pump. Vapor is pulled into the pump inlet which is then compressed and discharged through the exhaust to atmosphere. Benefits: No oil anywhere Long vane life Low vibration Graphite composite vanes Oil-less Rotary Vane Technology
- 32. Oil-less Rotary VaneTechnology
- 33. The impeller sitsbetween two end plates (port plates) which have shaped holes cut into them called ports. The pump requires a liquid (also called the sealant) to create vacuum as follows. ... This is the suction of the pump, drawing in air, gases, or vapors thru the "inlet port" at the sides of the impeller. Application Area Pharmaceutical Food & Confectionery Petro-chemicals Textile Plastic industries Paper and Sugar mills Cement Metallurgical Laboratories and Furnaces Refrigeration Plants Distilleries Liquid/Water Ring Vacuum Pumps
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- 36. One Stage RootsBlower Pump Assembly
- 37. VACUUM SYSTEM USE 1 2 3 4 5 6 7 8 9 10 11 12 Chamber Foreline RoughingValve Roughing Gauge Roughing Pump Foreline Foreline Valve Foreline Gauge High Vacuum Valve Booster/Blower Vent Valve High Vacuum Gauge 1 9 3 12 4 11 5 2 67 8 10 (irshad_alam@aol.com)
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- 39. Gauge Operating Ranges 10-1210-10 10-8 10-6 10-4 10-2 1 10+2 P (mbar) Rough VacuumHigh Vacuum Ultra High Vacuum Bourdon Gauge Thermocouple Gauge Cold Cathode Gauge Capacitance Manometer Hot Fil. Ion Gauge Residual Gas Analyzer Pirani Gauge Spinning Rotor Gauge McLeod Gauge
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- 41. How the gaugeworks
- 42. Heat Transfer Gauges Thermocouplegauge and Pirani Gauge
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- 44. How the gaugeworks
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- 46. Ionization current isthe measure of vacuum
- 47. Vacuum Pumps arebest suited for Pharmaceutical, Semiconductor, Aircraft, Automobile, Glass, Printing, Packaging, Chemical, Food Processing, Confectionary, Breweries, Distilleries, Plastic, Garment & Leather Processing Industries, Textiles, Paper & Sugar Mills, Power Plants, Furnaces, Cement & Fertilizer Plants, Metallurgical Laboratories and Vacuum Conveying, Extrusion, Priming, Dehydration, Filtration, Sterilizing, Tiles and Ceramics Industries and host of other industrial applications. APPLICATIONS
- 48. Thank You SoMuch for Your Valuable Time Most Welcome to Your Suggestion and Discussion With Warm Regards Mohammad Irshad Alam Sales Engineer Email: me_irshad@yahoo.com