Improvements in Apparatus for Concentrating Acids.
Year: 1891

page_text: Date of Application, 11th Feb., 1891
Complete Specification Left, 27th Oct., 1891-Accepted, 28th Nov., 189°
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Concentrating Acids.
1 WILHELM CARL HERAENS, of Hanau / Germany, Manufacturer, do
hereby declare the nature of this invention to be as follows:-
My invention relates to improvements in apparatus for concentrating acids, and
has for its object to form such apparatus or vessels, so as to withstand the action of
the acids, and also of intense heat, in a more efficient manner than heretofore.
When the vessels or apparatus, now in use for the concentration of sulphuric acid
and made of platinum, are given a coating of gold, over the parts that come in
contact with the acid, such vessels are made to better resist the action of the acid
and to last longer than such vessels or boilers, made of platinum only, because of
the well known fact that gold resists the most concentrated sulphuric acid better
than platinum, or any of its alloys.
Sheet platinum however, coated according to the well-known processes, with gold,
has some defects that render it less suited for the above purposes.
Sheet platinum gilded by the galvanic process, has proved to be not impervious
to the acid, so that an apparatus made of such sheet-platinum, is not very
durable.
The gold-platinum sheets made by mechanical means, have also proved to be
but little adapted for the construction of apparatus for concentration, because they
cannot withstand dry heating, or the heat of the higher temperatures, since the
layers of the two metals are easily separated in consequence of which the gold
peels off here and there.
It has also been shown to be impracticable to repair such an apparatus.
I therefore set to work in the following manner:
The sheet-platinum for constructing the boiler or the bottom thereof, is coated
with a layer of gold, by heating it to a temperature higher than the melting point
of gold and then running the molten gold over it, in some suitable mould or other
means.
The coating of these sheets by my process, results in good work being turned out,
and as it is very easy to heat the sheet-platinum, even when comparatively thick,
above the melting point of gold, and to cast over it a proportionately thick layer
of molten gold and then to submit the double-sheet or bar to the rolling process,
it will render the sheet-platinum readily adaptable for the construction of small
vessels, both pans and covers.
Such vessels would serve therefore as substitutes for the gold-pans and covers
required in chemical laboratories and for other purposes of a like nature.
Dated this 11th day of February 1891.
HUGHES, SON & Co.,
38, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Concentrating Acids.
I WILHELM CARL HERAENS, of Hanau /, Germany, Manufacturing Chemist,
do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
This invention relates to improvements in apparatus for concentrating acids, the
object of same being to form such apparatus or crucibles, so as to withstand

page_text: the action of the acids and also of intense heat, in a more efficient manner than
heretofore.
When the platinum vessels or apparatus now in use for the concentration of
sulphuric acid, are provided with a coating of gold over the parts that come in
contact with the acid, such vessels are rendered better able to resist the action of
the acid, and prove more endurable, than such vessels or crucibles, when made of
platinum alone. This is due to the well known property that gold possesses,
of being able to resist the action of the most concentrated sulphuric acid, better
than platinum or any of its alloys.
Sheet platinum however, coated according to the well-known processes with gold,
has some serious defects, which render it more or less unsuitable for the before-
described purposes.
Sheet platinum gilded by the galvanic process, has proved to be not impervious
to the action of the acid, so that an apparatus made of sheet platinum so treated,
is not durable enough for the purposes for which it is required.
The gold-platinum sheets made by mechanical means, have also proved to be but
little adapted for the construction of apparatus for the concentration of acids,
because they caunot withstand dry heating or the heat of the higher temperatures,
since the layers of the two metals are easily separated in consequence of which the
gold peels off here and there.
It has also been shown to be impracticable to repair such an apparatus.
According to my invention, I proceed in the following manner:
The sheet-platinum for constructing the boiler or the bottom thereof, is coated
with a layer of gold, by heating it to a temperature higher than the melting-
point of gold, and then running the molten gold over it, in any convenient form of
mould.
The coating of these sheets by my process, results in good work being turned
out; and as it is very easy to heat the sheet-platinum even when comparatively
thick, as when in the form of sheet-bars for instance-above the melting point of
gold, and to cast over it a proportionately thick layer of molten gold, and then to
submit the double-sheet or bar, to the rolling process, the sheet-platinum will be
rendered readily adaptable for the construction of small vessels. Such vessels
would serve therefore, as substitutes for the gold-pans and covers required in
chemical laboratories, and for other purposes of a like nature.
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:-
1. The preparation of metal for the manufacture of vessels for concentrating acids
by heating sheet-platinum above the melting temperature of gold, and running over
a layer of gold of suitable thickness, substantially as herein before
the same
described.
2. The production of crucibles and articles of a similar nature from metal,
prepared as hereinbefore described, and subsequently rolled out to the desired
thickness.
Dated this 27th day of October 1891.
HUGHES, SON & Co.,
38, Chancery Lane, London, Agents for the Applicant.