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A 200
About leak detection
GB 03302 - Edition 03 - July 12
Helium is the second most common element in the universe,
representing about 23 % of the total matter. 76 % is Hydrogen. All
other elements represent an insignificantly small fraction of the total.
Helium is a 100 % green gas and has absolutely no environmental
impact on the atmosphere.
Helium was discovered by spectroscopy in a solar eclipse on August
18, 1868. The discovery in the sun’s chronosphere gave the new
element its name: “helios” in Greek means “sun”. While Helium is
very common in the universe most of it is in the stars: on earth it is
actually not abundant. Since it is so light all the Helium present during
the formation of earth escaped to space.
Helium is created deep in the earth from the radioactive decay of
uranium and thorium which also gives the earth its internal heat. On
earth Helium was discovered in 1881 by spectroscopy of Mount
Vesuvio in Italy – the volcanic gases emanated by the mountain
showed the same lines in the spectrum as already known from the sun.
Helium concentration in the atmosphere is 5 times bigger than the
one of Krypton and 60 times higher than Xenon. The heavier noble
gases are isolated from air rectification. In contrary, Helium is “mined”
from natural gas and oil wells and stored. The annual world wide
production is ca. 3x10
7
m
3
or 4,500 tons.
Helium is constantly seeping up from the ground all around us, but it
is so light that almost all of it escapes into space fairly rapidly. On the
other hand there is a constant flow of Helium from space and the sun
to earth. This gives a dynamic equilibrium and is the reason for the
world wide constant concentration of 5 ppm Helium in air.
Helium is a very light colorless element and it is one of the six noble
gases which means it doesn’t react with anything for all practical
intents and purposes. It’s the most difficult gas to liquefy.
It’s used as an inert shield gas to protect things from oxidation – and
of course as leak detection tracer gas.
About helium and
hydrogen
Helium
adixen Vacuum Products - ASM 310 Operating instructions
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