VS Series Helium Mass Spectrometer Leak Detectors
DRAFT 4/23/15
B-5
B.3.2 Pressure Testing Method (Inside-out)
In this technique, the part is pressurized with helium or a mixture of helium and air, and
tested by one of the following methods.
B.3.2.1 Measuring Leaks
To de t e r m i n e the total q u a n t ity o f leakage ( b u t not the number or location of leaks), the part
is pressurized with helium (or a mixture of helium and air or nitrogen). This can be done by
bombing or backfilling small hermetically sealed parts. Larger parts can be actively
pressurized using a hose or tubing to deliver the helium. The part is placed in a volume that
is then evacuated by the leak detector. All the helium escaping from the part is captured and
quantified (Figure B-5).
Figure B-5 Measuring Leaks: Inside Out
B.3.2.2 Locating Leaks
To pinpoint t h e l o c a t ion o f t h e l eak(s) ( b u t n ot m e a s u r e t he t o t a l leakage), t he l i k e ly p o t e n t i al
leak sites of the part are scanned using a Sniffer Probe connected to the inlet of the leak
detector (Figure B-6).
Figure B-6 Locating Leaks: Inside Out
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