Fundamentals of Vacuum Technology (1248463), страница 2
Текст из файла (страница 2)
. . . . .68Evacuation of a chamber in the medium vacuum region . . . . .68Determination of a suitable backing pump . . . . . . . . . . . . . . . .69Determination of pump-down time from nomograms . . . . . . . .70Evacuation of a chamber where gases andvapors are evolved . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . .71Selection of pumps for drying processes . . . . . . . . . . . . . . . . .71Flanges and their seals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73Choice of suitable valves . . . . . . . . . . . . . . . . . . . . .
. . . . . . .73Gas locks and seal-off fittings . . . . . . . . . . . . . . . . . . . . . . . . .75Vacuum measurement, monitoring, controland regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Fundamentals of low-pressure measurement . . . . . . . . . . . . .76Vacuum gauges with pressure reading that is independentof the type of gas . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Bourdon vacuum gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Diaphragm vacuum gauges . . . . . . . . . . . . . . . . . . . . . . . . . .77Capsule vacuum gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77DIAVAC diaphragm vacuum gauge .
. . . . . . . . . . . . . . . . . . . .78Precision diaphragm vacuum gauges . . . . . . . . . . . . . . . . . . .78Capacitance diaphragm gauges . . . . . . . . . . . . . . . . . . . . . . .78Liquid-filled (mercury) vacuum gauges . . . . . . .
. . . . . . . . . . .79U-tube vacuum gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79Compression vacuum gauges (according to McLeod) . . . . . . .79Vacuum gauges with gas-dependent pressure reading . . . . . .81Spinning rotor gauge (SRG) (VISCOVAC) . . . . . . . . . .
. . . . . .81Thermal conductivity vacuum gauges . . . . . . . . . . . . . . . . . . .82Ionization vacuum gauges . . . . . . . . . . . . . . . . . . . . . . . . . . .83Cold-cathode ionization vacuum gauges(Penning vacuum gauges) . . . . . . . . . . . . . . . .
. . . . . . . . . . .83Hot-cathode ionization vacuum gauges . . . . . . . . . . . . . . . . . .84Adjustment and calibration; DKD, PTB national standards . . . .86Examples of fundamental pressure measurement methods(as standard methods for calibrating vacuum gauges .
. . . . . .87Pressure monitoring,control and regulation invacuum systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88Fundamentals of pressure monitoring and control . . . . . . . . . .88Automatic protection, monitoring and controlof vacuum systems . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .89Pressure regulation and control in rough and mediumvacuum systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90Pressure regulation in high and ultrahigh vacuum systems . . .92Examples of applications with diaphragm controllers . . . . . . . .935HomeTable of Contents4.4.14.24.34.3.14.3.1.14.3.1.24.3.1.34.44.4.14.4.24.4.34.4.44.54.5.14.5.24.5.34.5.44.5.54.5.64.5.74.64.6.14.6.24.6.34.6.44.74.7.14.7.24.7.34.7.44.84.955.15.25.2.15.2.25.35.45.4.15.4.25.4.35.4.45.4.55.4.65.4.75.4.85.4.95.5Analysis of gas at low pressures usingmass spectrometry . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .95General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95A historical review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95The quadrupole mass spectrometer (TRANSPECTOR) . . . . . .96Design of the sensor . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .96The normal (open) ion source . . . . . . . . . . . . . . . . . . . . . . . . .96The quadrupole separation system . . . . . . . . . . . . . . . . . . . . .97The measurement system (detector) . . . . . . . . . . . . . . . . . . . .98Gas admission and pressure adaptation .
. . . . . . . . . . . . . . . .99Metering valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99Pressure converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99Closed ion source (CIS) . . . . . . . . . . . . . . . . . . . . . .
. . . . . . .99Aggressive gas monitor (AGM) . . . . . . . . . . . . . . . . . . . . . . . .99Descriptive values in mass spectrometry (specifications) . . . .101Line width (resolution) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101Mass range . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .101Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101Smallest detectable partial pressure . . . . . . . . . . . . . . . . . . .101Smallest detectable partial pressure ratio (concentration) . . .101Linearity range . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .102Information on surfaces and amenability to bake-out . . . . . . .102Evaluating spectra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102Ionization and fundamental problems in gas analysis . . . . . .102Partial pressure measurement . . . . .
. . . . . . . . . . . . . . . . . .106Qualitative gas analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . .106Quantitative gas analysis . . . . . . . . . . . . . . . . . . . . . . . . . . .107Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108Standard SQX software (DOS) for stand-alone operation(1 MS plus, 1 PC, RS 232) . . . . . .
. . . . . . . . . . . . . . . . . . . .108Multiplex/DOS software MQX(1 to 8 MS plus 1 PC, RS 485) . . . . . . . . . . . . . . . . . . . . . . .108Process-oriented software ÐTranspector-Ware for Windows . . . . . . . . . . . . . . . . . . . . . . .108Development software TranspectorView . . . . . . . . .
. . . . . . .109Partial pressure regulation . . . . . . . . . . . . . . . . . . . . . . . . . .109Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109Leaks and their detection . . . . . . . . . . . . . . . . . . . . . . . . . .110Types of leaks . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110Leak rate, leak size, mass flow . . . . . . . . . . . . . . . . . . . . . . .110The standard helium leak rate . . . . . . . . . . . . . . . . . . . . . . . .112Conversion equations . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . .112Terms and definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112Leak detection methods without a leak detector unit . . . . . . .113Pressure rise test . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .113Pressure drop test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114Leak test using vacuum gauges which are sensitiveto the type of gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.114Bubble immersion test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115Foam-spray test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115Vacuum box check bubble . . . . . . . . . . . . . . . . . . . . . .
. . . . .115Krypton 85 test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115High-frequency vacuum test . . . . . . . . . . . . . . . . . . . . . . . . .115Testing with chemical reactions and dye penetration . . . . . . .115Leak detectors and how they work . . . .
. . . . . . . . . . . . . . . .1165.5.15.5.25.5.2.15.5.2.25.5.2.35.5.2.45.5.2.55.5.2.65.5.2.75.5.2.85.5.2.95.65.75.7.15.7.25.7.35.7.3.15.7.3.25.7.45.866.16.26.36.46.56.66.76.86.96.1077.17.27.2.17.2.27.2.37.2.47.37.3.17.3.2Halogen leak detectors (HLD 4000, D-Tek) . . .
. . . . . . . . . . .116Leak detectors with mass spectrometers (MS) . . . . . . . . . . . .116The operating principle for a MSLD . . . . . . . . . . . . . . . . . . . .117Detection limit, background, gas storage in oil(gas ballast), floating zero-point suppression . . . . . . . . . . . . .117Calibrating leak detectors; test leaks . .
. . . . . . . . . . . . . . . . .118Leak detectors with quadrupolemass spectrometer (ECOTEC II) . . . . . . . . . . . . . . . . . . . . . .119Helium leak detectors with 180¡ sector mass spectrometer(UL 200, UL 500) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119Direct-flow and counter-flow leak detectors .
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