vacuum 真空获得与测量.ppt

Why is a Vacuum Needed? Why is a Vacuum Needed? HOW DO WE CREATE A VACUUM? BAROMETER Pressure Equivalents Viscous and Molecular Flow FLOW REGIMES MEAN FREE PATH FLOW REGIMES Roughing Pumps PUMP OPERATING RANGES VACUUM SYSTEM USE Rotary Vane, Oil-Sealed Mechanical Pump Pump Mechanism How the Pump Works Pump Down Curves OIL FOR ROTARY VANE PUMPS Dry Vacuum Pumps Roots Pump One Stage Roots Blower Pump Assembly VACUUM SYSTEM USE HIGH VACUUM PUMPS PUMP OPERATING RANGES VACUUM SYSTEM USE Oil Diffusion Pump How the Pump Works Rotor - stator assembly Roughing through the turbo Gauges Gauge Operating Ranges Bourdon Gauge How the gauge works Heat Transfer Gauges Thermocouple gauge and Pirani Gauge Thermocouple Gauge How the gauge works Ionization gauges Ionization current is the measure of vacuum LEAK DETECTION Problems that appear to be Leaks Double O ring sealed Differential Pumping Leak rate Why Helium is used HELIUM Helium is very light and small Low concentration in air (0.0005%) Permits dynamic testing Permits non-destructive testing Helium is safe Ion Separation in Magnetic Field Tracer probe leak detection technique Pump Operation Molecule V Moving Wall with Speed V Principle of the Turbomolecular Pump Turbomolecular pump 1 - High vacuum connection flange. 2 - Stator pack. 3 - Venting connection flange. 4 - Fore-vacuum connection flange. 5 - Splinter guard. 6 - Rotor. 7 - Pump casing. 8 - Bearing. 9 - Motor. 10 - Bearing. 1 2 3 4 5 6 Chamber Turbo Pump Roughing Pump Vent Valve Roughing Gauge High Vac. Gauge 1 6 7 4 3 2 5 2 10-12 10-10 10-8 10-6 10-4 10-2 1 10+2 P (mbar) Rough Vacuum High 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 Capacitance Manometer Capacitance Manometer Pirani Gauge Our Gauges Components used in Vacuum system flange Pipe valve Blank Flanges KF (10 to 50) ISO (63 to 500) CF (16 to 300) Right-Angle Valve