Fundamentals of Vacuum Technology (1248463), страница 3
Текст из файла (страница 3)
. . . . . . . . . . . . .120Partial flow operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120Connection to vacuum systems . . . . . . . . . . . . . . . . . . . . . . .121Time constants . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .121Limit values / Specifications for the leak detector . . . . . . . . . .122Leak detection techniques using helium leak detectors . . . . .122Spray technique (local leak test) . . . . . . . . . . . . . . . . . . . . . .122Sniffer technology (local leak testing using thepositive pressure method) . . . . . . . . . . . . . . . . . . . . .
. . . . . .123Vacuum envelope test (integral leak test) . . . . . . . . . . . . . . .123Envelope test Ð test specimen pressurized with helium . . . . .123a) Envelope test with concentration measurement andsubsequent leak rate calculation . . . . . . . . . . . . . . . . . . .123b) Direct measurement of the leak rate with the leakdetector (rigid envelope) . . . .
. . . . . . . . . . . . . . . . . . . . .123Envelope test with test specimen evacuated . . . . . . . . . . . . .123a) Envelope = Òplastic tentÓ . . . . . . . . . . . . . . . . . . . . . . . . .123b) Rigid envelope . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .123ÒBombingÓ test, ÒStorage under pressureÓ . . . . . . . . . . . . . . .123Industrial leak testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124Thin film controllers and control units with quartzoscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125Introduction . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .125Basic principles of coating thickness measurementwith quartz oscillators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .125The shape of quartz oscillator crystals . . . . . . . . . . . .
. . . . . .126Period measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127The Z match technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127The active oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. .127The mode-lock oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . .128Auto Z match technique . . . . . . . . . . . . . . . . . . . . . . . . . . . .129Coating thickness regulation . . . . . . . . . . . . . . . . . . . . . .
. . .130INFICON instrument variants . . . . . . . . . . . . . . . . . . . . . . . .131Application of vacuum technology forcoating techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133Vacuum coating technique . . . . . . . . . . . . . . . . . . . . . . . . . .133Coating sources . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .133Thermal evaporators (boats, wires etc.) . . . . . . . . . . . . . . . . .133Electron beam evaporators (electron guns) . . . . . . . . . . . . . .134Cathode sputtering . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . .134Chemical vapor deposition . . . . . . . . . . . . . . . . . . . . . . . . . .134Vacuum coating technology/coating systems . . . . . . . . . . . . .135Coating of parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135Web coating . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1356HomeTable of Contents7.3.37.3.47.3.5Optical coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136Glass coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137Systems for producing data storage disks . . . . .
. . . . . . . . . .13788.1Instructions for vacuum equipment operation . . . . . . . . .139Causes of faults where the desired ultimate pressure isnot achieved or is achieved too slowly . . . . . . . . . . . . . . . . .139Contamination of vacuum vessels and eliminatingcontamination . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .139General operating information for vacuum pumps . . . . . . . . .139Oil-sealed rotary vacuum pumps(Rotary vane pumps and rotary piston pumps) . . . . . . . . . . .140Oil consumption, oil contamination, oil change . . . . . . . . . . .140Selection of the pump oil when handling aggressive vapors .140Measures when pumping various chemical substances . .
. . .141Operating defects while pumping with gas ballast ÐPotential sources of error where the required ultimatepressure is not achieved . . . . . . . . . . . . . . . . . . . . . . . . . . . .142Roots pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142General operating instructions,installation and commissioning .
. . . . . . . . . . . . . . . . . . . . . .142Oil change, maintenance work . . . . . . . . . . . . . . . . . . . . . . .142Actions in case of operational disturbances . . . . . . . . . . . . . .143Turbomolecular pumps . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .143General operating instructions . . . . . . . . . . . . . . . . . . . . . . . .143Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143Diffusion and vapor-jet vacuum pumps . . . . . . . . . .
. . . . . . .144Changing the pump fluid and cleaning the pump . . . . . . . . . .144Operating errors with diffusion and vapor-jet pumps . . . . . . .144Adsorption pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144Reduction of adsorption capacity . . . . . . .
. . . . . . . . . . . . . . .144Changing the molecular sieve . . . . . . . . . . . . . . . . . . . . . . . .144Titanium sublimation pumps . . . . . . . . . . . . . . . . . . . . . . . . .145Sputter-ion pumps . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . .145Information on working with vacuum gauges . . . . . . . . . . . . .145Information on installing vacuum sensors . . . . . . . . . . . . . . .145Contamination at the measurement system and its removal .146The influence of magnetic and electrical fields . . . . . . . . . . . .146Connectors, power pack, measurement systems . . . .
. . . . . .1468.28.38.3.18.3.1.18.3.1.28.3.1.38.3.1.48.3.28.3.2.18.3.2.28.3.2.38.3.38.3.3.18.3.3.28.3.48.3.4.18.3.4.28.3.58.3.5.18.3.5.28.3.68.3.78.48.4.18.4.28.4.38.4.49.Tab ITables, formulas, nomograms, diagrams and symbols . .147Permissible pressure units including the torr and itsconversion . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147Tab IIConversion of pressure units . . . . . . . . . . . . . . . . . . . . . . . . .147Tab III Mean free path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147Tab IV Compilation of important formulas pertaining to thekinetic theory of gases . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .148Tab VImportant values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .148Tab VI Conversion of pumping speed (volume flow rate) units . . . . .149Tab VII Conversion of throughput(a,b)QpV units; leak rate units . .
. . . . . . . . . . . . . . . . . . . . . . . . .149Tab VIII Composition of atmospheric air . . . . . . . . . . . . . . . . . . . . . . .150Tab IX Pressure ranges used in vacuum technology and theircharacteristics . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .150Tab XOutgassing rate of materials . . . . . . . . . . . . . . . . . . . . . . . . .150Tab XINominal internal diameters (DN) and internal diametersof tubes, pipes and apertures with circular cross-section(according to PNEUROP). . . . . . . .
. . . . . . . . . . . . . . . . . . . .151Tab XII Important data for common solvents . . . . . . . . . . . . . . . . . . .151Tab XIII Saturation pressure and density of water . . . . . . . . . . . . . . . .152Tab XIV Hazard classificationof fluids . . . . . . . . .
. . . . . . . . . . . . . . . .153Tab XV Chemical resistance of commonly used elastomergaskets and sealing materials . . . . . . . . . . . . . . . . . . . . . . . .155Tab XVI Symbols used invacuum technology . . . . . . . . . . . . . . . . . . .157Tab XVII Temperature comparison and conversion table . . . . . . . . . . .160Fig. 9.1 Variation of mean free path λ (cm) with pressurefor various gases .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .160Fig. 9.2 Diagram of kinetics of gases for air at 20¡C . . . . . . . . . . . . .160Fig. 9.3 Decrease in air pressure and change in temperatureas a function of altitude . . . . . . . . . . . . . . . .
. . . . . . . . . . . . .161Fig. 9.4 Change in gas composition of the atmosphere as afunction of altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .161Fig. 9.5 Conductance values for piping of commonly usednominal internal diameters with circular crosssection for molecular flow . . . . . . . . . . . .
. . . . . . . . . . . . . . .161Fig. 9.6 Conductance values for piping of commonly usednominal internal diameters with circular crosssection for molecular flow . . . . . . . . . . . . . . . . . . . . . . . . . . .161Fig. 9.7 Nomogram for determination of pump-down time tpof a vessel in the rough vacuum pressure range . .
. . . . . . . .162Fig. 9.8 Nomogram for determination of the conductance oftubes with a circular cross-section for air at 20¡Cin the region of molecular flow . . . . . . . . . . . . . . . . . . . . . . . .163Fig. 9.9 Nomogram for determination of conductance oftubes in the entire pressure range . . . . . . .
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