MENTS IN THE MANUFACTURE OF TIN PLATE
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Dr. Francesco Belluomini at the Office
of the Commissioners of Patents on the 16th July 1877.
DR. FRANCESCO BELLUOMINI, of Florence, in the Kingdom of Italy.
MENTS IN THE MANUFACTURE OF TIN PLATE."
"IMPROVE-
The new method of manufacturing iron tin plate which I invented consists in the
substitution of refractory clay cases in the place of the cast-iron boxes hitherto
employed for the annealing of the iron plates, and in the use of colophony in the
tinning process in place of grease or palm oil. Plates of iron coated with tin
constitute tin plate.
The iron plate during the various processes it undergoes before being tinned
becomes raw and brittle and is unfit for folding; in order to remedy this defect it
is annealed in closed boxes of cast iron in particular ovens for the annealing of
closed vessels. The ovens having been heated for several hours are allowed to cool,
and the hermetically closed boxes are only opened and the plates removed when
cold. The continual changes of temperature cause a great consumption of the cast-
iron boxes, in fact Jullien calculates on an average that there is an outlay of
Fr. 1.60 or 18. /4d. in boxes for every 100 kilograms of annealed iron plate, which
would be equivalent to Fr. 0-81c or 81d for every case of tin plate marked I G.
It is therefore of the highest advantage in the manufacture of tin plate that there
should be found an economical method of annealing the iron plate in closed cases
made of a material which costs little, which stands fire better than cast-iron and
which effects equally useful results. The above results I have succeeded in
obtaining by the adoption of refractory clay cases which possess all the needful
requirements.
The advantage of price which would result from the substitution of refractory
clay cases in the place of cast-iron boxes for annealing the iron plates may be
calculated above 50c. or 5d. per case of tin plate.
The iron plates, in order to become tin plate, receive a coating of tin. Previous
to the tinning process the iron plates must be thoroughly cleansed from oxide, and
to avoid the re-formation of oxide they are kept in water until they are to be
tinned. As the plates would not take on the tin coating were they plunged wet
with water into the tin, they have to be dipped into a substance which removes the
water and covers them with a coating so as to protect them from oxidation.

page_text: Hitherto the plates have been iminersed in grease or oil previous to being plunged
into the tin pot. By this method a kilogram of grease or oil was consumed for
every case of tin plate. I have found that colophony produces the same effect and
can therefore be perfectly safely substituted for grease or oil. The great advantage
of this discovery may be estimated by the fact that grease or oil costs from Fr. 100
to 120 per hundred kilograms, and that colophony costs on an average Fr. 24 to 26;
consequently there would be a saving of 60c. or 6d. for every case of tin plate.
The cases for annealing the iron plate should be made of refractory clay, should
be solid and of the same form as those of cast iron. They should exceed in size by
15 or 57/8 inches in length, and by 5c. or 2 inches in breadth, the iron plates they
contain. When the plates are deposited in the cases the covers should be laid on
and be made tight with clay to prevent the air from penetrating. The cases are
then introduced into the oven and are heated in the usual manner.
The colophony should be of ordinary quality and having been melted in ordinary
pots employed for the grease it should be kept in a state of fusion. The wet iron
plates should be plunged vertically one by one into the resin pot, and be left there
until the cessation of the ebullition produced by the water in the colophony They
should then be removed by means of tongs and be immersed into the tin pot. The
remainder of the process should be effected in the ordinary manner.
I trust that the modifications which I have introduced into the manufacture of
tin plate may prove to be of the highest importance.