Alcatel ASM 180 TD User Manual page 23

Sniffer method
Alcatel Vacuum Technology France - ASM 180 TD/TD+ - ASM 181 TD+ User's Manual
Testing methods
The test part is pressurized with helium. The detector, via an
LDS (Long Distance Sniffer) probe, collects the helium esca-
ping from the part.
Global test
He
Part
Sniffer probe
The part is placed under a
cover containing a sniffer
probe.
The leak cannot be located.
The helium from the leak
accumulates over time inside
the cover. The detector
measures the concentration.
Local sniffing test
or
He
Part
Detector
The sniffer probe is moved
over areas likely to contain
leaks.
The leak can be located.
The signal supplied by the
analyzer is not a direct
measurement of the leak.
The sniffer probe only
collects part of the helium
escaping from the part
depending on the distance
separating the leak from the
tip of the probe.
A 40
Detector
Sniffer probe
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