Once the part
is sealed correctly, it is placed into the test chamber
and over the pneumatically operated expanding seal. The
lid is then pulled down over the test chamber to the closed
position and the cycle start button operated for that chamber
on the centre module HMI.
The part is
sealed from the chamber and the chamber is sealed from atmosphere.
The component is then evacuated to a pre-set level and held
there for a time interval to monitor for any large leak
created by the pressure differential (termed 'Gross Leak').
A fail at this point will reset the cycle.
If the test
is passed then both the component and the chamber are evacuated
to a lower pre-set level. A fixed volume of Helium is then
injected into the component producing a 140mBar pressure
differential between the component and chamber. The chamber
vacuum line is switched to the mass-spectrometer which monitors
for helium leakage from the component into the chamber (termed
A label printer
will dispense the appropriate label based upon the data
entered by the operator if the test was successful. This
is scanned using a hand-held barcode reader for verification.
that fail due to gross or fine leaks are held for leak location.
The leak location
test requires the component to be evacuated, then filled
with Helium at 1140mBar Absolute (to produce the 140mBAR
pressure differential above atmospheric) A hand-held probe
connected to the mass-spectrometer is then used to manually
locate helium concentrations indicating leaks in the test