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Niles, Donald E. (ed.) / The Wisconsin engineer
Volume 48, Number 3 (November 1943)

[Cover] Wisconsin engineer,   pp. [unnumbered]-[1]

The Rubber
       with roots
  two miles deep!
TIHE ATAKING OF svntbetic rubber in-
   volves among other things the exact
control of gas mixtures of great coin-
plexity. Formerly the analysis of some
gases required several (lays of painstak-
ing laboratory work, and in some cases a
complete analysis was impossible.
  Westinghouse scientists-working in
close collaboration with engineers of lead-
ing oil and chemical conmpanics-have
lerfecte(l an electronic "chemist" which
is an important addition to the present
methods of analysis.
  'With the imp)roved technique and ap-
paratlls now available, the time required
for accurately making some of these
aialyses has been reduced to an hour
or lcss!
  An amazing electronic device...
  knowit as the mass spectrometer
  ... not olnly improves the accuracy
  of the synthetic rubber process,
  but frees hundreds of skilled
  chemists front tedious but impor-
  tant production testing in these
T' me mass spectrometer analyzes gases
by sorting the molecules-according to
their mass-in (roughly) the samne way
that a cream separator sorts out the
cream from whole milk.
  Let's say we want to analyze a simple
gas mixture containing onie part of oxv-
gen anll(l 10,000 parts of nitrogen. Here's
I low tIle Iniiss spectromneter accomplishes
this icedrc(lib le feat:
  First, the gas sample is bombarded
with electrons. This ionizes the nitrogen
and oxygen molecules, giving them elec-
trical charges of their own.
  These ions are then drawn by elec-
trical force into a curved vacuum tube.
Here, ions of different molecular weights
whizz around different curved paths-de-
pending upon their reaction to a power-
ful electromagnet surrounding the tube.
  The heavier oxygen ions follow a
straighter path than the lighter nitrogen
ions and are directed through a tiny exit
slit onto a plate where they give up their
electrical charge. The amount of this
charge, amplified and recorded by sen-
sitive electrical instruments, is an ex-
tremely accurate measure of the quantity
of oxygen in the gas mixture.
  The starting voltage is then changed
to allow the nitrogen ions to pass through
the same exit slit-thus measuring the
quantity of nitrogen. This same principle
applies to the analysis of complex hydro-
carbon mixtures.
  The development of the mass
  spectrometer . . . for the quick,
  accurate analysis of butadiene...
  is a typical example of the way
  Westinghouse "know how" in elec-
  tronics is tackling the wartime
  problems of industry in an effort
  to speed victory.
'Westinghouse Electric & Manufacturing
Company, Pittsburgh, Pennsylvania.
We stin house

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