Product description
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At the time of spraying, the leak rate does not appear instantly. There is a response time
which depends on the volume V to be tested and on the tracer gas pumping speed S of
the system at part's inlet, according to the ratio:
T = V/S (T in seconds, V in litres, S in l/s).
T is the time after which the leak rate reaches 63 % of the final value.
Bombing method The part is placed ahead of time in a pressurised gas tracer chamber.
The tracer gas penetrates the part through the potential leaks.
Then the part is removed from the chamber and placed in another vacuum chamber and
connected to the detector.
The detector measures the flow of tracer gas that leaks out of the part.
4.3.2 Sniffing test
● Part that can be connected to pipe and cannot be placed under a vacuum
The part to be tested is pressurised with tracer gas.
Using a sniffer probe passed over all the points likely to leak, the detector collects the
tracer gas that escapes from the part. The detector measures the flow of tracer gas that
leaks out of the part.
The measured leak rate is not an exact measurement of the leak.
The sniffer probe only detects part of the tracer gas escaping from the part, depending
on the distance separating the crack from the tip of the probe, and the direction of the
leak in relation to the probe.
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