Improvements in the process of Steel, or other Metal Plates with Tin or other Metal.
Year: 1888

page_text: Improvements in the process of
Steel, or other Metal Plates with Tin or other Metal.
I, ADOLPH GUTENSOHN, of Ford Road, Old Ford, in the County of Middlesex,
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 :-
My invention relates more especially to the manufacture of tinned plates, or plates
of sheet iron or steel coated with metallic tin, and it has for its objects improvements
in the process of tinning or coating such plates, and also in the apparatus used in the
process, by which improvements considerable economy is effected in the cost of the
process and in the tin used, and in the apparatus used.
In the method of tinning plates most ordinarily used, the sheet iron or steel plates
first pickled by acid for the purpose of cleaning the surface, are placed whilst still wet
a considerable number together into a large pot or vessel of melted grease. From
this pot the plates are removed into a pot of melted tin where they remain for a few
minutes and are then removed to an adjoining platform where each plate is brushed
by hand upon both sides, and is then dipped into a second pot of melted tin, after
removal from which it is dipped into a grease pot and is then passed between rollers
which give it its finished appearance.
In this process there is considerable waste both of material and of labour, and the
work is very hard and requires men to perform it.
In another process which is occasionally used the plates to be tinned are kept in a
small tank of water, whence each is taken singly and passed through a large pot of
melted tin, the plates being carried down into the tin by one set of rollers and brought
out by a second set. The plates are then again dipped into a small pot of melted
tin, after removing them from which they are finished in a final pot, as in the process
first described.
In this process also there is considerable waste. The melted tin in the tinning pot

page_text: 15 covered with a flux, usually chloride of zinc, and the plates pass wet through this
flux into the tin, a very large proportion of dross being produced.
By my present invention I effect great economy, first in the production of a very
much less quantity of dross, and secondly in the quantity of tin required the pots used
being smaller.
The more wet a plate is when dipped into the melted metal the more dross is
produced, as the water being decomposed supplies oxygen one of the principal
constituents of the dross; and my invention has for one of its objects the sufficient
and effectual removal of the water from the surface of the plate before the latter is
dipped into the melted tin.
I take the wet plates from the acid bath in which they have been pickled, (preferably
by the electrical process for which Letters Patent were granted to Adolph Gutensohn,
and James Meyer James, dated June 23rd A.D. 1886, and numbered 8824) and after
washing or swilling I place them in a small tank filled with a solution by which the
last trace of acid is removed. This solution is alkaline, and preferably consists of a
mixture (or soap) of carbonate of ammonia and of palm oil in small proportions which
may be varied more or less as may be found advisable.
From this tank I remove the plates one by one and I pass them between three pairs
of rollers of suitable size for the plates which are being treated and set in motion by
any convenient power. The first pair of rolls are of metal and are adjusted in
sufficiently close proximity to each other by adjusting screws or springs and they
serve to flatten and straighten the plate and to guide it into the second pair of rolls
which are preferably of india rubber or other substance soft enough to squeeze off all
the moisture from both sides of the plate, and leave it clean and dry. From these
rollers the plate passes between the third pair which may be either hard as for
instance of metal, or soft as of leather or wood, and the surfaces of which are coated
with a thin coat of grease, either by making the lower one revolve in a vessel of
suitable melted grease or by supplying a sufficient quantity of the latter to them from
a hopper above, or in other convenient way. From the last pair of rollers the plate is
dipped into one or two pots of melted tin, (of which only one may be used, but two
are preferable), after removal from which it is passed through the usual finishing pot
of melted grease whence it is taken finished. If the surface of the melted tin in the first
tinning pot is covered with a sufficient quantity of melted grease, the third pair of
rollers for greasing the plate can be dispensed with, the plate passing direct from the
squeezing or drying rolls into the melted tin, but as such pot has to be very hot thero
is always danger of the large quantity of grease required catching fire and considerable
inconvenience being thus caused, whilst by the use of the greasing rollers only a very
thin film upon the surface of the melted tin is necessary, and the plates are in the best
condition to take the tin readily and quickly.
One or more of the pairs of rollers may be heated by steam or other means, if
desired.
By the use of the alkaline neutralizing solution in the way described, the plates
come from the soft squeezing rolls smooth and bright and in the best condition for
tinning, whilst the solution itself removes a considerable quantity of oxide of iron
from their surface which would otherwise (as in the former processes) pass into the
grease of the first grease poi, or into the flux (where flux is used as in the second
ordinary process described) as sulphate or chloride, according to the acid which has
been used for pickling the plates.
If the rolls are used cold, I prefer to use for greasing them a mixture of palm oil,
resin, and linseed oil, in such proportions that the mixture does not set when cold.
Where wood or a substance not affected by oil or grease is used, the third pair of
rollers described for greasing may be omitted, the second pair being used for greasing
as well as for squeezing and drying as described.
By my invention, both the process and apparatus are materially simplified and
cheapened, whilst the plates produced are excellent in quality.
Plates may be coated with other metals (as for instance lead) instead of tin.
5

page_text: 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 improved process, consisting in first neutralizing any acid remaining upon
the surface of the plate by means of an alkaline solution, then passing the plate
between rollers of hard material by which it is flattened and guided between a second
pair of softer rollers by which all the moisture is removed its surface being slightly
greased either by the same rollers, or by passing it between another pair of rollers so
that the plates are squeezed dry and greased on their surface in one operation, and
thence passing it into and through a sufficient number of pots or vessels of the melted
metal with which it is to be coated, without the necessity of any flux, substantially as
described.
2. The apparatus, consisting of a tank of alkaline solution, hard flattening and
guiding rollers, soft squeezing and drying rollers, and hard or soft greasing rollers,
and one or more dipping and finishing pots of the usual kind, substantially as
described.
3. The omission of the hard or soft greasing rollers described in the second claim,
and the use of the soft squeezing and drying rollers for the purpose also of greasing
the plates, substantially as described.
Dated this 18th day of April 1888.
EDWARDS & Co.,
35, Southampton Buildings, London, W.C.,
Agents for the Applicant.