Process for Preventing the Chemical Action of Acids and other Corrosive Liquids on Metal Containers, Conduits, and the like.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Process for Preventing the Chemical Action of Acids and other
Corrosive Liquids on Metal Containers, Conduits, and the like.
1, CHRISTIAN ALBERT JENSEN, of No. 77 Chancery Lane, in the County
of Middlesex, Chartered Patent Agent, do hereby declare the nature of this
invention (a communication to me from abroad by Alf Sinding-Larsen of
No. 49 Huitfeldt's Gade Christiania in the Kingdom of Norway Electrical
Engineer) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The metal vessels or other receptacles for boiling or containing reagents or
acids which are extensively used in chemical industries are as is well known
covered with some material for resisting the deleterious effects of the acids and
the like. The coverings or linings are therefore not only costly and difficult to
keep in order but they are also generally disadvantageous. These linings are
particularly troublesome when used in the boilers employed for the production of
cellulose. This invention has for object to obviate altogether the use of such
linings.
The invention is based upon the fact that the chemical action of two substances
on one another depends upon the electrical tension between the two substances.
If an acid for instance, under normal conditions has no effect on a metal, then the
metal will by an alteration of the conditions of tension be dissolved by the acid,
while by an alteration in the opposite sense, another action will take place. In
like manner, supposing under ordinary conditions of tension, the metal is dissolved
by the acid, then there exists a degree of tension at which this action is annulled,
and so on.
The invention is consequently carried out in such manner, that the metal vessel
is inserted in the circuit of an electric current of like polarity the other pole of
which consists of a conducting material hanging in the fluid and the current is so
regulated that the corrosive action of the liquid on the metal walls of the vessel is
stopped. It must be particularly noted that the current must be accurately
regulated or otherwise a disadvantageous decomposing action will take place
which it is not intended should happen.
This process is applicable for cellulose boilers and also for vessels for boiling down
acids and caustic alkaline lyes and for all other similar cases which occur in chemical
industry. All according to the form of the vessels the form of the electrode
immersed in the liquids has to be so chosen that a tension as uniform as possible
is obtained everywhere. Thus in a cylindrical boiler the electrode is arranged
in the axis of the vessel in the form of a long rod which is shorter than the boiler
to the extent of the diameter of the latter. This electrode is suitably supported
in and insulated from the boiler it is however electrically connected to one
terminal of a dynamo or other source of electricity and the shell of the boiler is
electrically connected to the other terminal.
The object of the invention cannot be carried out in the manner previously
proposed for similar purposes, that is to say, not in that manner where metallic
parts are brought into the vessel which is to be protected which metallic parts
are dissolved by the liquid and thereby produce an electrical action. By these
known processes the composition of the liquid is altered because the metallic parts
in question are dissolved. The application of such methods is therefore
confined to special cases in which the contamination by a metallic salt is of no
importance.

page_text: The present invention consists in the process whereby every chemical secondary
reaction is excluded; from this reason the electrode immersed in the liquid is
made of a material chemically indifferent and the electric current is carried to
the electrode from without. Under such conditions only can the process be
applied for a manufacture as for instance for the production of cellulose because
as is well known the cellulose fibres are, especially as to colour, very sensitive in
the presence of metallic salts.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
The process for protecting metallic vessels against the influence of acids and
other corrosive liquids consisting in inserting the vessel as a pole in an electric
circuit of like polarity which is fed from a special source of electricity, the other
pole being formed by a chemically indifferent electrode immersed in the liquid in
the vessel.
Dated thin 05th dow of I... 100%
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.