This retort is
carried above a burner using fuel gas or other means of generating heat and
this burner is lighted after the chemical charge is mixed and compressed in
the tube.
The generation of gas commences and the oxygen is led through water baths
which wash and cool it before storing in a tank connected with the plant.
From this tank the gas is compressed into portable cylinders at a pressure
of about 300 pounds to the square inch for use as required in welding
operations.
Each pound of chlorate of potash liberates about three cubic feet of
oxygen, and taking everything into consideration, the cost of gas produced
in this way is several times that of the purer product secured by the
liquid air process.
These chemical generators are oftentimes a source of great danger,
especially when used with or near the acetylene gas generator, as is
sometimes the case with cheap portable outfits. Their use should not be
tolerated when any other method is available, as the danger from accident
alone should prohibit the practice except when properly installed and
cared for away from other sources of combustible gases.
ACETYLENE
In 1862 a chemist, Woehler, announced the discovery of the preparation of
acetylene gas from calcium carbide, which he had made by heating to a high
temperature a mixture of charcoal with an alloy of zinc and calcium. His
product would decompose water and yield the gas.
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