Alcatel Vacuum Technology France - ASM 180 TD/TD+ - ASM 181 TD+ User’s Manual
Testing methods
Edition 03 - May 97
A 40
1/4
Leak detection is used to detect micro-openings, porosities,
etc. in test parts. The detection of these passages involves the
use of a light gas, which is capable of infiltrating the smallest
passages quickly:
Helium
.
The detector samples and measures the helium flow rate
entering the test part via the leak(s).
The testing method is selected according to the test part and
the measurement accuracy required:
The part can
be connected to
an evacuation line
The part is sealed
BOMBING method
Leak not located
SPRAY method
Leak rate measurement from
10
-10
to 10
-1
mbar and
possibility of locating the leak
SNIFFING method
Minimum detectable leak of
10
-6
mbar and possibility of
locating the leak
Its characteristics
allow it to be
evacuated
Its characteristics
allow it to be
pressurised with helium
or a mixture containing
helium
Its characteristics
allow it to be placed
in a vacuum
vessel
yes
yes
yes
yes
no
no