High Vacuum Systems Design

Vacuum pumping ports leading to the vacuum pumps must be designed to optimise conductance.

High vacuum systems design. Capture pumps operate at lower flow rates than transfer pumps but can provide ultra high vacuum down to 10 12 torr and generate an oil free vacuum. Ultra high vacuum uhv is the vacuum regime characterised by pressures lower than about 100 nanopascal 10 7 pascal 10 9 m bar 10 9 torr uhv conditions are created by pumping the gas out of a uhv chamber. Leakage prevention is especially important with vacuum systems because even very small leaks can greatly diminish performance and efficiency. For clean pumping in the ultra high vacuum range 10 9 torr sputter ion pumps non evaporable getter neg and ti sublimation pumps can be used.

Temperature and pressure during periods when the chamber is at atmosphere and during the rough pumping portion of the cycle. Pressure relief valves to be incorporated where a vacuum system can be vented to 10 kpa above atmospheric pressure. A typical vacuum system consists of a vacuum source delivery lines fittings and various control valves switches filters and protective devices. Together these pumps can cope with all the gases normally found in clean all metal vacuum systems and by themselves have lower limit pressures in the 10 11 to 10 12êtorr range.

At these low pressures the mean free path of a gas molecule is greater than approximately 40 km so the gas is in free molecular flow and gas molecules will collide with the. Capture pumps operate using cryogenic condensation ionic reaction or chemical reaction and have no. Asme state that the design of an external pressure vessel must consider material type. A schematic arrangement of a typical vacuum system with a high vacuum valve.

Gauge w i n isolation valve water cooled baffle. Abbess high vacuum hv chamber systems are engineered and fabricated meticulously to meet exacting performance standards and are combined with select pumping systems thermal subsystems sensors and control configurations to ensure performance is precise and reliable at hv levels 10e 4 to 10e 9 torr. J b inlet valve t c. Knowing the critical factors of a system such as ultimate pressure maximum gas loads effective speeds and system conductances gives valuable insight to the system operation.

Hopefully this short engineering design series will help in aiding the design process of high vacuum systems especially for those operating on tight and limited budgets. Design of high vacuum systems t c.