IMPROVEMENTS IN THE MANUFACTURE OF TIN PLATES, WHICH INVENTION IS ALSO APPLICABLE FOR THE COATING OR COVERING OF METAL SURFACES FOR OTHER PURPOSES."
Year: 1880

page_text: LETTERS PATENT to Edward Parry, of New Bridge Street, in the City of
London, Iron Merchant, and Thomas Henry Cobley, of Dunstable, in the
County of Bedford, for an Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF TIN PLATES, WHICH INVENTION IS ALSO APPLICABLE FOR THE COATING OR
COVERING OF METAL SURFACES FOR OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Edward Parry and Thomas
Henry Cobley at the Office of the Commissioners of Patents on the 16th March
1880.
EDWARD PARRY, of New Bridge Street, in the City of London, Iron Merchant,
and THOMAS HENRY COBLEY, of Dunstable, in the County of Bedford. "IMPROVE-
MENTS IN THE MANUFACTURE OF TIN PLATES, WHICH INVENTION IS ALSO APPLICABLE
FOR THE COATING OR COVERING OF METAL SURFACES FOR OTHER PURPOSES."
Our Invention relates to improvements in the manufacture of tin plates, being
also applicable for the coating or covering of metal surfaces for other purposes.
It may be used advantageously for coating iron wire with another metal, also for
the production of zinc plates, and for similar purposes.
It comprises, first, the depositing of a coating of zinc, which (when the zinc is to
receive a coating of tin) forms an insulating or intermediate substance; and,
secondly, the depositing of an ultimate coating of tin upon the zinc when tin plates
or other tinned articles are to be produced. The interposition, according to our
Invention, of a layer or coating of zinc between the iron and the metal which is to
form the outer surface enables us to dispense entirely with the use of grease or oil
in the process of coating with tin, and has, moreover, the effect-of-rendering the
-finished plates much less liable to oxidation than is the case with those in whose
manufacture grease or oil has been employed.
According to our Invention the coating of the iron plates or other articles with zinc
is effected as follows, that is to say:-We take ore of zinc (for instance the sulphide),
and after roasting the same we obtain the sulphate formed by the roasting by dis-
solving or digesting the mass in water, and leave the oxide for recuperating the bath;
or we may take the carbonate of zinc in a roasted or unroasted state and attack-it
with any available acid (for instance, sulphuric acid), and convert this ore of zinc
also into a sulphate. With the solution of sulphate of zinc thus obtained we form
Price A

page_text: a bath, preferably of a strength of 2 pounds of sulphate of zinc to every gallon of
water employed (more or less); the iron plates or articles, having been previously
cleansed or pickled in a proper solution of sulphuric, hydrochloric, or acetic acid, or
of chloride of calcium and ammonium to remove any oxides or other extraneous
impurities, are immersed in the said bath, and an electric current from a battery,
an electro-magnetic, dynamo-electric, or thermo pile electric machine, or from any
other suitable generator of electricity, is passed into the said bath, employing an
"indifferent" anode, that is to say, an anode consisting of any suitable metal or
substance which will not be attacked by the acid set free during the operation of
coating. We prefer for this purpose copper or platinised copper, but may use any
other metal platinised, or antimony, or alloys of antimony, carbon, or any similar
substance or material; and in some cases we may employ metallic zinc coated with
mercury. This anode will therefore be permanent instead of consisting, as is usual,
of a piece of the metal to be deposited.
We may, however, under some circumstances employ anodes of metallic zinc
made by casting zinc scrap into plates, and we may substitute zinc ash for zinc ore
where circumstance will admit of this, but whatever anode we may employ the
bath will in all cases consist of a solution of zinc to be deposited either obtained
direct from the ore as above described or from the ash.
When the said bath of sulphate of zinc becomes reduced to the condition that
the deposition ceases to be sufficiently energetic, then this reduced solution forming
the bath is run off and recuperated by bringing it in contact with fresh ore
prepared in the manner hereinbefore described; this recuperated solution is again
run into the bath and the operation proceeded with, and so on.
The employment of the zinc ore or ash in the manner above explained instead of
depositing from an anode composed entirely of the metal which is to form the
coating effects a great economy, and the coating of zinc thus deposited enables
us to produce tin plates with about half the quantity of tin usually employed,
for the reason that more tin must be used if deposited directly upon the iron than
when there is an intermediate layer of zinc.
If the zinc-covered plates obtained as above described are to be made into tin
plates they are coated with tin in an ordinary tinning bath containing galvanic
tinning solution, or they are coated in a bath by means of electro-deposition, such
bath being prepared from tin ore, tin ash, slag, or scoria by boiling the ore, ash,
slag, or scoria in an alkaline solution with an excess of caustic soda, or roasting it
with an excess of caustic soda and lixiviating the roasted mass. Or if we require
a chloride bath we convert the tin oxide by any convenient and well known means
and use it in connection with chloride of ammonium.
In the process of depositing the tin by electricity we prefer to employ anodes
which are not attacked by the acid. Scrap tin subjected to hydraulic pressure may
also be employed for the anodes.
The plates after being coated with zinc may, if necessary, be passed through
rollers to give them a more even surface for the subsequent tinning operation.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Parry and Thomas Henry Cobley in the Great Seal
Patent Office on the 16th September 1880.
EDWARD PARRY, of New Bridge Street, in the City of London, Iron Merchant,
and THOMAS HENRY COBLEY, of Dunstable, in the County of Bedford. "IMPROVE-
MENTS IN THE MANUFACTURE OF TIN PLATES, WHICH INVENTION IS ALSO APPLICABLE
FOR THE COATING OR COVERING OF METAL SURFACES FOR OTHER PURPOSES."
Our Invention relates to improvements in the manufacture of tin plates, and is
applicable for the coating or covering of metal surfaces for other purposes.
The said Invention comprises the deposition upon the ordinary iron plates of a
zinc coating which (when the zinc is subsequently to receive a coating of tin) forms
an insulating or intermediate substance, and an important feature of the said
Invention consists in the novel means employed for coating the iron plates or other
articles with zinc, as hereinafter described. It also comprises the deposition of an
ultimate coating of tin upon the zinc when tin plates or other tinned articles are to
be produced.
The interposition, according to our Invention, of a layer or coating of zinc between
the iron and the metal which is to form the outer surface enables us to dispense
entirely with the use of grease or oil in the process of coating with tin, and has,
moreover, the effect of rendering the finished plates so obtained much less liable to
oxidation than is the case with those in whose manufacture grease or oil has been
employed.
According to our Invention the coating of the iron plates or other articles with
zinc is effected as follows, that is to say:-
We take ore of zinc (for instance the sulphide), and after roasting the same we
obtain the sulphate formed by the roasting by dissolving or digesting the mass in
water, and we leave the oxide for recuperating the bath in which the plates are
coated; or we may take carbonate of zinc in a roasted or unroasted state and
attack it with any available acid (for instance; sulphuric acid), or with a solution of
sulphate of iron, producing thus, by double decomposition, carbonate of iron and
sulphate of zinc, and we convert this ore of zinc also into a sulphate. With the
solution of sulphate of zinc thus obtained we form a bath, preferably of a strength
of 2 pounds of sulphate of zinc to every gallon of water employed; the proportion
may, however, be more or less according to circumstances; the iron plates or
articles having been previously cleansed or pickled in a proper solution of sulphuric,
hydrochloric, or acetic acid, or of chloride of calcium and ammonium to remove any
oxides or other extraneous impurities, are immersed in the said bath, and an electric
current from a battery, an electro magnetic, or thermo-pile electric machine, or from
any other suitable generator of electricity, is passed into the said bath through an
anode consisting, or partly consisting, of any suitable metal or substance which will
not be attacked by the acid set free during the operation of coating. We prefer for
this purpose lead or copper, which may or may not be platinized, but we may use
any other platinized metal, or antimony, or alloys of antimony, carbon, or any
similar substance or material, and in some cases we may employ metallic zinc
coated with mercury.
This anode will therefore be permanent instead of being
formed, as is usual, of the actual metal to be deposited.
-We-may, however, under-some-circumstances employ-anodes-of-metallic-zinc
made by casting zinc scrap into plates, and we may substitute zinc-ash for zinc-ore
where circumstances will admit of this. But whatever anode we may employ, the
bath will in all cases consist of a solution of the zinc to be actually deposited either
obtained direct from the ore as above described or from the ash.
When the said bath of sulphate of zinc becomes reduced to the condition that the
deposition ceases to be sufficiently energetic, this reduced solution forming the bath is

page_text: run off and recuperated by bringing it in contact with fresh ore prepared in the manner
hereinbefore described; this recuperated solution is again run into the bath and the
operation proceeded with, and so on continuously. The employment of the zinc ore
or ash in the manner above explained instead of depositing from an anode composed
entirely of the metal which is to form the coating effects a great economy, the
coating of zinc thus deposited enabling us to produce tin plates with about half the
quantity of tin usually employed, for the reason that more tin must be used if
deposited directly upon the iron than when there is an intermediate layer of zinc.
If the zinc-covered plates obtained as above described are to be made into tin
plates we coat them with tin in an ordinary tinning bath containing galvanic
tinning solution, or they may be coated by means of electro deposition, the bath
being prepared from tin ore, or tin ash, or slag, or. scoria containing tin by boiling
the ore, ash, slag, or scoria in an alkaline solution with an excess of caustic soda, or
roasting it with an excess of caustic soda and lixiviating the roasted mass. Or if
we require a chloride bath we convert the tin oxide previously prepared by any
convenient and well known means, and use it in connection with chloride of
ammonium.
In the process of depositing the tin by electricity, anodes which are not attacked
by the acid may be employed, but this method does not produce a good lustre or
color in the tin, therefore we prefer to employ tin anodes. Scrap tin subjected to
hydraulic pressure may be employed for the anodes.
The plates after being coated with zinc may, if necessary, be passed through
rollers to give them an even surface for the subsequent tinning operation, and both
the zinc and tin plates are polished by passing them through revolving discs or
similar suitable polishing devices.
Although we have described specially advantageous means for coating the iron
plates with zinc, we desire it to be understood that the layer of zinc when it is to
be subsequently coated with tin may be applied to the iron in any other suitable
manner.
Having thus fully described our said Invention, and the manner of performing
the same, we wish it understood that we claim,―
First. The manufacture of tin plates by first coating iron plates with zinc, and
then depositing tin upon the zinc coating.
Second. The manufacture of zinc plates by depositing zinc upon iron plates in
the manner above described.
Third. The process of depositing zinc upon metal surfaces by employing a
solution of zinc ore or zinc ash in a bath, and in the manner above described.
Fourth. The employment of tin ore, tin ash, or slag, or scoria containing tin, in
the manner above described, as a coating for metal surfaces which have been
previously coated with zinc, for the purposes specified.
Fifth. In the electro-deposition of zinc upon metal surfaces, the employment of
an anode consisting, or partly consisting, of lead, copper, or other metal or material
which will not be attacked or decomposed by the acid in the bath, as above set
forth.
In witness whereof, we, the said Edward Parry and Thomas Henry Cobley,
have hereunto set our hands and seals this Sixteenth day of Cantanhas