1 / 9

Vacuum tests

Vacuum tests. Problem description Valve presentation Test setup Measurements & Results Conclusions. Problem description. Secondary vacuum. Separated primary and secondary vacuum to obtain good ring vacuum Thin foil required because of multiple scattering

quynh
Télécharger la présentation

Vacuum tests

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vacuum tests • Problem description • Valve presentation • Test setup • Measurements & Results • Conclusions

  2. Problem description Secondary vacuum • Separated primary and secondary vacuum to obtain good ring vacuum • Thin foil required because of multiple scattering • Intrinsically safe solution is desired Thin foil Electronics, cables, etc. Primary vacuum

  3. Valve presentation • Valves that react to differential pressure • Electric/Pneumatic, but… • Fail-safe solution required • Proposal: Gravity controlled valve

  4. Test setup • Leak rate during normal operation (with/without pump) • Preliminary: • Dynamic response to sudden pressure changes (leaks) • System behavior during pump down Removed picture of vacuum test setup

  5. Test setup (2) Sander Klous 24-11-2000

  6. Measurements & Results • Conductance (H2O): • 10-3 liter/sec without dedicated pump • 10-5 liter/sec with dedicated pump • Expected secondary vacuum pressure: 10-4 mbar This would result in 10-9 mbar l/s leak-rate Pumping slots

  7. Measurements & Results (2) • Dynamic response • Maximum differential pressure over the valve is 6 mbar • Measurement is dominated by the bellow configuration (see picture) • More realistic measurements are required with faster gauges Removed picture of tandem (gravity-controlled) valves

  8. Measurements & Results(3) Secondary vacuum • Pump down time • Conductance between primary and secondary vacuum: Bellows (L = 1 m, d = 20 mm) • Maximum pressures in range of the gauges: 500 mbar, calibrated with a baratron. • 3 hours to around 1 mbar (p = 9 mbar at 500 mbar) • 3 hours to 10-5 mbar Bellow Primary vacuum Restriction Valve 2 Valve 1 Primary pump Turbo pump

  9. Conclusions • All measurements indicate the gravity controlled valve can work • For the correct dynamic pressure analysis a more realistic setup is required

More Related