Year: 1886

page_text: Date of Application, 23rd June, 1886.
Complete Left, 15th Mar., 1887.
Complete Accepted, 15th Apr., 1887.
We, ADOLPH GUTENSOHN of Mile End Road, in the County of Middlesex, Manu-
facturing Chemist, and JAMES MEYER JAMES, of Bucklersbury, in the City of
London, Merchant, do hereby declare the nature of this invention to be as
follows:-
In the process of pickling or preparing the surface of iron, steel, or other metals, to
receive a coating of tin, or other metal, it has been usual to immerse the articles to be
pickled, in an acid bath and to leave them there until the surface is entirely free from
rust or scale.
In the case of tin-plates, the iron, steel or other plates are pickled before they enter
the annealing furnace and again before they are dipped. The first pickling is called
the black pickling, the second the white. After a certain number of articles have
been pickled in the acid, heat applied, for the purpose of quickening the action of
the acid which becomes slow, and when the heat ceases to sufficiently hasten the action
of the acid, the latter (which contains a large quantity of iron in solution) is called
waste acid, and is in most cases allowed to run away as its commercial value is too
small to allow its utilization. In this way very large quantities of acid are wasted
annually and the object of the present invention is to prevent this waste altogether, or
at least to considerably reduce it.
In order to do so we use an Electric current from any suitable generator, preferably
where the process is to be carried on upon a large scale a dynamo machine of any
suitable kind, and we place the articles to be pickled in a bath and suitably connect
them with one pole whilst the other pole is connected with a copper or other plate or
plates or bar or bars conveniently placed in the said bath.

page_text: By the action of the electric current acid is set free and the scale or rust on the
surface of the articles is removed and deposited on the surface of the said copper or
other plate or in the bath.
This process can be continued for a long time, which is still further extended if a
small proportion of fresh acid is added to the solution, and in this way a great saving
is effected, the cost of the Electric current not being greater than that of the steam
ordinarily used to heat the solution, whilst by the improved process a large quantity of
the iron is recovered as spongy iron or as oxide, the value of which is sufficient to
cover a large part of the cost of the acid.
Dated this 23rd day of June 1886.

page_text: COMPLETE SPECIFICATION.
Improvements in the Process of Pickling or Cleaning the Surface
of Iron or other Metal Previous to Coating such Surface with
Tin or other Metal.
We, ADOLPH GUTENSOHN, of Mile End Road, in the County of Middlesex, Manu-
facturing Chemist, and JAMES MEYER JAMES, of Bucklersbury in the City of London,
Merchant, 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 (that is to say) :-
This invention relates to what is known as the process of "pickling" or treating
with acid the surface of sheet metal plates or other articles, in order to prepare them
to receive a coating of metallic tin or other metal, as for instance in the manufacture
of tin plate. It has for its object improvements in the said process of pickling or
cleaning, by which improvements great economy in the cost of the process and in the
time required is effected and more efficient results are produced.
In the process of pickling or preparing the surface of iron, steel or other metals to
receive a coating of tin or other metal, it has heretofore been usual to immerse the
articles to be pickled in a bath of diluted acid (such as sulphuric or hydrochloric
acid), and to leave them there until the surface is entirely free from rust or
scale.
In the case of tin plates, the iron, steel or other plates are pickled before they enter
the annealing furnace and again before they are dipped in the molten tin. The first
pickling is called the black pickling, the second the white pickling.
After a certain number of articles have been thus pickled in the acid the action of
the latter becomes slower, and heat is accordingly applied for the purpose of quickening
its action, and when the acid has been in use so long that heat ceases to sufficiently
hasten its action, it is called waste acid, and (though containing a large quantity of
iron in solution) is in most cases allowed to run away to waste, its commercial value
being too small to allow its utilization.
In this way very large quantities of acid are wasted annually, and one object of the
present invention is to prevent this waste, or at least to considerably reduce it.
For the purpose of our invention we use an electric current from any suitable
generator, preferably, where the process is to be carried on upon a large scale, a
dynamo machine of any suitable kind, and we place the plates or articles to be pickled
in a bath or vessel containing the pickling liquid. We do not confine ourselves to any
particular kind of liquid, as the choice of either acid or alkaline solution rests with the
locality and the time within which the pickling: is to be done. For instance, in
tin plate works, where a certain quantity of plates is to be done regularly and quickly,
an acid is to be preferred, whereas in galvanized iron works it may happen that time
is of less consequence, in which case almost any solution, either spent acid or alkalino
solution (such as caustic soda) may be employed.

page_text: For both these works it is essential that the plates should be so pickled that they are
uniformly alike clean, without spots or roughness on any part; and to achieve this the
arrangement of the way of using the electric current is of the utmost importance, and
therefore our arrangement is a special feature of the invention.
If it was only a question of pickling or removing the scale or rust from the surface
of iron, it would be sufficient to place the articles to be cleaned into an acid or alkaline
solution, connect them with one pole, and connect the other pole with a bar or plate or
any suitable piece of metal in the bath, but to do the pickling so as to produce articles
suitable for being coated uniformly with any other metal, we use an arrangement such
as the following.
We line a suitable wooden tank with sheet iron or other metal, so that the lining
forms a moveable tank inside the wooden one. The parts of this lining need not
be connected so as to form a water-tight tank, as the outer wooden one is itself
water-tight.
The inner lining should be without flanges, so as to prevent the possibility of short
circuiting. The bottom of the inner lining is preferably about two inches from the
bottom of the wooden tank, and is perforated, so as to allow the impurities to settle
down underneath and be removed without emtying the whole of the tank. In this
inner tank is placed, at a sufficient distance from it, a wooden crate or other support
or supports of wood or other non-conducting material. The support or supports are
provided with suitable metallic connections, by which all the plates are properly
electrically connected with one another and with one pole of the generator, the other
pole of which is connected with the lining of the tank. The sheets or plates or
articles placed in the crate or supports as described are thus cleaned uniformly, and
present a beautiful appearance when removed from the solution, whilst the iron or
scale which is removed from their surface is deposited upon the metal lining, which
thus increases in thickness if a not too strong current is employed, whereas a very
powerful current deposits oxide, which can be washed off from time to time and settles
down underneath the bottom of the inner lining, whence it can easily be removed from
time to time and converted into a marketable article.
The action of the electric current admits of the pickling liquid being used for a long
time; but, in case of despatch being essential, and acid being used as already
indicated, the addition of a small proportion of fresh acid from time to time is advisable.
By our invention a great saving is effected, as the acid can be used for a much
longer time than has heretofore been the case, and all the iron is deposited,
whereas hitherto iron and acid together have been allowed to run away to waste.
The solution being used cold, in connection with the electric current, the noxious
fumes which now fill a pickling room when heat is applied is avoided.
Having now particularly described and ascertained the nature of our said Invention,
and in what manner the same is to be performed, we declare that what we claim is :-
The method of using electricity to quicken and improve the process of "pickling"
or cleaning the surface of iron or other metal previous to coating such surface with tin
or other metal, and to effect the deposit and recovery of iron or other metal, or the
oxides thereof, or other substances removed during such process, substantially in the
manner described.
EDWARDS & Co.,
35, Southampton Buildings, London,
Agents for the Patentees.