Adixen ASM 182 TD PLUS, Руководство пользователя

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4/5
A 401
About Helium and hydrogen
GB
02760
- Edition
01
- Februar
y
05
GB
02760
- Edition
01
- Februar
y
05
5/5
A 401
About Helium and hydrogen
And now some
wrong ideas
Helium is rare Yes , it is, but helium is an inexhaustible resource from the heart of
the earth.
Helium is recovered most cost-effectively from natural gas and long-
term contracts guarantee access to sources in the USA, Europe and
North Africa.
No , because the mass spectrometer doesn’t required high level purity
helium to detect accuratly the leaks (97,5 % is enough).
Helium ( Air Liquide and Linde sources, Europe)
Purity Average market price (2004)
in € /m
3
99,995 % 27
97,5 % => helium gas tracer 8
No , because to have a safe hydrogen tracer gas, you have to use
mixture (95 % N2 + 5 % H2).
Let see the following prices:
Average market price (2004)
in € /m3
Helium Purity: 97,5 % 8
Hydrogen Mixture
95 % N2 + 5 % H2
25 to 30
Helium is expansive
Hydrogen is less expensive
than Helium
Security: Hydrogen isn’t
dangerous ?
No , theoretically hydrogen isn’t dangerous , if ….and if….
But reality is different and if all the mixtures of H
2
+ inert gas in a
bottle have a limited life time , probably, the bottle isn’t so safe. The
reason is: because of the weight of H
2
(the lightest element), over the
time a stratification phenomenon occurs which leads to gas emanation
of uncontrolled Hydrogen concentration at the top of the gas bottle
and can detonate or be flammable in contact of air or oxygen.
If gas producers recommendation is “always roll on the floor a mixture
H2 bottle before use”, it is to avoid the stratification phenomena and
to recover homogeneous mixture.
Alcatel Vacuum Technology France - User's Manual ASM 182/192 TD+ - ASM 192 T2D+ Alcatel Vacuum Technology France - User's Manual ASM 182/192 TD+ - ASM 192 T2D+