The mineral sediment that generally sticks to the sides of steam boilers,
and the presence of which is fraught with the utmost danger, resulting in
many instances in great injury to life and property, besides eating away
the substance of the iron plate, was referred to in a paper lately read by
M. Jeannolle before the Paris Academy of Sciences, in which the author
described a new method for keeping boilers clean. This method is as
follows:
The inside of a steam boiler is placed, by means of piles of a certain
power, in reciprocal communication, the current passing at one end through
positive, and at the other through negative, wires. In incrusted steam
boilers, at a temperature ranging from 212° to 300° Fahr., and a pressure
of from 30 to 90 lb. to the square inch, the current thus engendered
decomposes the accumulated salts, and precipitates them, from which they
may easily be removed, either by means of a special siphon or by means of
some other mechanical process. When boilers are free from fur, and where
it is intended to keep them free from such, a continuous current may be
set up, by means of which the sedimentary salts may be decomposed, and a
precipitate produced in a pulverized form, which can be removed with equal
facility.
From a series of minute experiments made by M. Jeannolle, it appears that
in order to render the various actions of electricity, perfect, it is
necessary to coat either with red lead or with pulverized iron, or with
any other conductor of electricity, an operation which must be repeated
whenever the boiler is emptied with a view to cleaning out. The above
system Is being advantageously applied in Calais for removing the
incrustations of boilers. The two poles of a battery of ten to twelve
Bunsen elements are applied to the ends of the boilers, and after thirty
to forty hours the deposits fall from the sides to the bottom. When a
boiler has been thus cleared, the formation of new deposits may be
prevented by applying a much less energetic current under the same
conditions.
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