IMPROVE- MENTS IN OBTAINING SOLID CAUSTIC SODA FROM FUSED CAUSTIC SODA
Year: 1885

page_text: I, WALTER WELDON, of Rede Hall, Burstow, in the County of Surrey Fellow of
the Royal Society, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN OBTAINING SOLID CAUSTIC SODA FROM FUSED CAUSTIC SODA,"
a communication from abroad from Messieurs A. R. Pechiney et Compagnie,
Chemical Manufacturers, of Salindres (Gard), in the Republic of France, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention consists in a method of obtaining from fused caustic soda solid
caustic soda in films or sheets, susceptible of being readily converted into more or
less, finely powdered solid caustic soda by crushing or grinding or breaking up the
said films or sheets before they have become cold.
The said method of obtaining from fused caustic soda solid caustic soda in films
or sheets consists in bringing into contact with the fused caustic soda the exterior
surface of a revolving hollow cylindrical or other body, of metal or other suitable
material, the heat of fusion of the caustic soda being carried off by water or other
suitable refrigerating agent passed into and through the interior of the said hollow
revolving body.
The two accompanying sheets of drawings represent dispositions of apparatus by
which the said method of obtaining from fused caustic soda films or sheets of solid
caustic soda, and afterwards crushing the said films or sheets into small fragments,
may be performed.
In Sheet 1, Figures 1 and 2, A is a hollow iron cylinder, which turns on hollow
axles C, C, supported by the framework D, D. At I is a cock through which water
is admitted into the cylinder A, passing into it by a pipe which bends down to
near the bottom of A, the water so admitted into A passing out from near the top
of A by the pipe K. Below the cylinder A is placed a small reservoir B, preferably
of wrought iron. Fused caustic soda is fed into this reservoir B, by the same
means as those by which it is at present fed into the iron "drums" in which
מ:

page_text: caustic soda is now usually sold, or by any other convenient means. As the
cylinder A revolves, it dips a little below the surface of the fused caustic soda in B,
and emerges coated with a film of solid caustic soda, which on reaching the knife
or scraper E, Figure 1, is detached from the cylinder, and falls into a conduit from
which it falls between the toothed rollers G, H, Figure 1, which crush it into
small fragments, which then fall into a conduit placed below the toothed rollers,
from which conduit the crushed caustic soda is finally delivered into casks or other
suitable receptacles.
In Sheet 2 is represented another disposition of apparatus for carrying into effect
the aforesaid method of obtaining from fused caustic soda in films or sheets, and
afterwards crushing the solid caustic soda so obtained. In this disposition of
apparatus there are two hollow cylinders, A and B, placed in relation to each other
as is indicated in the drawings, and turning in opposite directions, as indicated by
the arrows in Figure 1. At each extremity of the cylinder A is a flange, which
overlaps the corresponding extremity of the cylinder B, as shown in Figure 1.
C is a hopper into which the fused caustic soda is charged. In the lower part of this
hopper is a narrow longitudinal opening or slit, through which the fused caustic
soda falls on to the two cylinders A and B, at the point at which these cylinders
touch each other. The hopper C is furnished with an appliance, as shown in
Figure 1, by which the opening or slit at the bottom of that hopper can be partially
closed at will, and whereby the rate at which fused caustic soda falls on the two
cylinders can thus be regulated. The two cylinders are kept cooled by water
continually passing through them, essentially in the same manner as in the case of
the disposition of apparatus first described. E and F, Figure 1, are knives or
scrapers which detach the crusts of solid caustic soda from the two cylinders
respectively. The solid caustic soda then falls between two toothed rollers, as will
be understood from Figure 1. This Figure gives an end view of the apparatus,
and Figure a view of it from above.
It will be understood that my correspondent does not confine himself to the
exact details of the methods of performing his invention which have now been
described, since those details may be varied in many ways without departing from
the nature of his invention; but both the dispositions of apparatus which are
described above are dispositions by means of which his invention can conveniently
be performed. Such apparatus can of course be used without the toothed rollers,
when it is not desired to crush the solid caustic soda into small fragments; or with
more than one pair of rollers, when it is desired to crush the solid caustic soda
more finely than it is crushed by a single pair of rollers. And of course apparatus
other than the described rollers may be employed for the operation of crushing
or grinding the films or plates of solid caustic soda obtained in the manner
constituting the present invention'.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
Obtaining solid caustic soda from fused caustic soda by bringing the fused
caustic soda into contact with the exterior surface of a hollow revolving cylindrical
or other body cooled by water or other refrigerating agent passed into and through
the interior of the said hollow cylindrical or other body.
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