Vacuum Testing Method (Outside-In; Locating Leaks: Outside In; Measuring Leaks: Outside In - Agilent Technologies VS Series Operation Manual

D.3.1 Vacuum Testing Method (Outside-in)
The part to be tested is evacuated with a separate pumping system for large volumes, or
with just the leak detector itself. When the appropriate cross over pressure has been
reached, the leak detector is valved-in or transfers into test and the part is tested using one of
the following methods:
D.3.1.1 Locating Leaks
To pinpoint the location of the leak(s) (but not measure the total leakage rate), helium is
administered to the suspected leak sites of the part using a spray probe with an adjustable
flow (Figure D-3).
D.3.1.2 Measuring Leaks
To determine the total quantity of leakage (but not the number or location of leaks), the part
is connected to the leak detector and shrouded by a helium environment. This helium
environment can be contained in many methods ranging from a simple plastic bag to more
complex bell jar arrangements (Figure D-4).
D-4
VS Series Component Leak Detector
Figure D-3 Locating Leaks: Outside In
Figure D-4 Measuring Leaks: Outside In