Working Principle; Hydrogen Trace Gas For Leak Detection; Interferences - Adixen H2000 PLUS 5.0 Manual Del Usuario

2. Working principle

Hydrogen Trace Gas for leak detection

When pure hydrogen gas is released in air
its flammability region spans from 4% to
75% of hydrogen in air. Below 4% there is
insufficient chemical energy available for
a flame to propagate. Above 75% hydrogen
there is not enough oxygen left to support
a flame.
When, for example, a mixture of less than
5.7 % hydrogen in nitrogen mixes with
air there is not sufficient energy to sup-
port a flame, irrespective of the ratio of
air-to-gas.
When a mixture of more than 5.7 % hydro-
gen in nitrogen is released into air there is
a region of ratios of air-to-gas where the
mixture is flammable. When, for example, a
mixture of 10% hydrogen in nitrogen mixes
with air there is still very little energy av-
ailable. Only in exceptional circumstances
can a flame be self-supporting. However,
such mixtures cannot detonate.
Hydrogen/nitrogen mixtures con-
taining more than approximately
15% hydrogen can detonate when
mixed in certain proportions with
air.
Warning!
• Never use a gas mixture containing more than 5% hydrogen.
• Never make your own gas mixtures.
Never make your own mixtures. Only
use ready-made mixtures, or use a certified
hydrogen/nitrogen mixer installed by your
gas supplier.

Interferences

Most trace gas methods suffer from some
sort of interference. Either the detector is
sensitive to other gases or vapours, or there
are other sources of the gas present to which
the detector is sensitive.
Some examples of hydrogen sources:
- Engine exhaust
- Battery charging stations
- Welding smoke
- Cigarette smoke
- Breathing air
- Human flatulence
- Scratching on aluminium
Hydrogen Leak Detector H2000
is extremely selective. Only Hydrogen
Sulphide (extremely toxic) gives a compa-
rable response to hydrogen.
Adixen Scandinavia - User's manual H2000 PLUS
GB
PLUS