IMPROVEMENTS IN THE MANUFACTURE OF TIN PLATES AND TERNE OR LEADED PLATES, AND IN PROVISIONAL SPECIFICATION
Year: 1859

page_text: LETTERS PATENT to Robert Valentine Leach, of Briton Ferry, in the
County of Glamorgan, and of Devizes, in the County of Wilts, Tin Plate
Manufacturer, and Thomas William Willett, of Pont-Neath-Vaughan, in
the County of Brecon, Civil Engineer, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF TIN PLATES AND TERNE OR LEADED PLATES, AND IN
PROVISIONAL SPECIFICATION left by the said Robert Valentine Leach
and Thomas William Willett at the Office of the Commissioners of
Patents, with their Petition, on the 23rd May 1859.
We, ROBERT VALENTINE LEACH, of Briton Ferry, in the County of Gla-
morgan, and Devizes, in the County of Wilts, Tin-plate Manufacturer, and
THOMAS WILLIAM WILLETT, of Pont-Neath-Vaughan, in the County of Brecon,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF TIN PLATES AND TERNE OR LEADED
PLATES, AND IN THE APPARATUS CONNECTED THERE WITH," to be as follows:-
At present, after coating the plate in the tin or terne pot and brushing it,
it is the common practice to dip the coated plate in the wash pot, and after-
wards for the purpose of regulating the weight of the coating to dip it in the
grease pot, as is well understood. The defects of this arrangement are, that

page_text: as the plate is dipped in and removed from the wash pot by hand only, that
therefore the weight of the coating upon the plates is necessarily very irregular,
so that even were the periods of their immersion in the grease pot strictly
equal and uniform in duration, the result would yet not be a uniform weight of
coating upon each plate, but the operation of dipping in the grease pot is itself
performed by hand only, and the period of its duration is itself irregular. The
result in practice is found to be, that the weight of the coating upon the plates
varies considerably. The process is also open to this further great objection,
that not only is there a want of uniformity in the weight of the coating upon
the plates, but also from the manner in which the operation is conducted the
coating itself is very unequally distributed over the surface of each plate.
The molten coating runs from the upper towards the lower edge of the
plate, and in practice the result is that the thickness of the coating gradually
increases from the top edge to the bottom, where it accumulates in a mass,
which has afterwards to be removed by the process of listing.
Now, the object of our Invention is to obtain a more uniform weight of
coating upon every plate, and also more evenly' to distribute that weight of
coating over its entire surface. For this purpose we employ suitable racks,
capable of holding at one time several plates at uniform distances apart.
These racks are so constructed, that by suitable mechanical means acting in
connexion with some motive power (by preference water), they can be lowered
into or raised from both the wash pot and the grease pot at determined speeds.
Immeadiately after the operation of brushing, a fixed number of plates are
placed in one of these racks, which is then immersed in the wash pot; here
it remains for a brief interval, and is then raised above the surface of the
coating metal; the effect is, that every plate in the same rack thus receives a
like weight of coating, and as the operation can be almost exactly repeated,
any number of plates may in like manner receive an equal weight of coating.
The plates thus coated are then in the same or a similar rack, and by similar
mechanical means simultaneously dipped in the grease pot, and as every plate
in the rack has been subjected to an exactly similar treatment, it will be found
that each has upon it a like weight of coating, but in order that this like
weight of coating upon each plate may be evenly and uniformly distributed
over its surface, we so determine the speed at which the rack is immersed in
and withdrawn from the grease-pot, that the rack enters the grease pot at a
gradually increasing speed, and leaves it at a gradually decreasing speed, and
we can thus subject the thicker coating which was left upon the lower portion
of the plate as it came from the wash pot for a longer determined period
of time to the action of the grease pot, and by properly proportioning this

page_text: varying speed to the size of the plate and the temperature of the coating metal,
we can obtain a very even coating.
The following is another arrangement by which also we obtain an equal
distribution of the coating upon each plate. The plates as they come from
the wash pot are placed horizontally at even distances apart in a suitable rack;
this rack when filled is immersed in the grease pot, where it is allowed to
remain stationary for about one minute; it is then, by suitable mechanical
means, caused to rotate at a determined speed, and for a determined time, upon
a vertical axis; this speed is so proportioned to the size of the plate and the
temperature of the metal, that by reason of the centrifugal force, a greater or
less portion of the superfluous coating is thrown off from the edge of the plate,
and the time of rotation is proportioned according to the quantity of the coating
which it is. desired to remove. Before withdrawing the rack from the grease
pot, it is allowed to remain stationary for about another minute, in order that
the coating metal may equalize itself upon the surface by flowing from the
edges towards the centre of the plate, which it is disposed to do in consequence
of that part being the lowest portion.
For the commoner descriptions of tin and terne plates, where the weight of
the coating metal is small, we determine the weight of the coating metal upon
each plate by means of a grease pot, either such as is in common use, or
(which we prefer) similar to that herein-before described, and we afterwards
arrange the plates in a suitable rack in a position nearly horizontal, and then
immerse them again in a grease pot. In this case the holding rack. is not
caused to rotate, but remains stationary in the grease pot for a determined
time; the effect of this operation is greatly to improve the appearance of the
plate by equalizing the coating upon its surface.
In arranging the plates in the rack for this last operation, we take care to
place that edge of the plate which was before downward in the grease pot a
little higher than the other edge, so that the coating has a tendency to flow
from the thicker to the thinner portion.
Our last improvement consists in a new apparatus for listing. This con-
sists in the employment of a flat metal plate (by preference of copper, smooth
upon its surface, and tinned.) This plate is placed at an inclination of about
80 degrees, and is heated by a suitable flue:
The plates are arranged in a suitable rack, and the edge that is to be listed
rests upon the tinned copper. The effect is to heat the edge of the plate and
remove the superfluous portion which then runs from the inclined surface, and
by this means we effect a more even and accurate listing.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Valentine Leach and Thomas William Willett in
the Great Seal Patent Office on the 22nd November 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ROBERT
VALENTINE LEACH, of Briton Ferry, in the County of Glamorgan, and of
Devizes, in the County of Wilts, Tin-plate Manufacturer, and THOMAS
WILLIAM WILLETT, of Pont-Neath-Vaughan, in the County of Brecon, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of May, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said Robert Valentine Leach and Thomas William Willett, Her special licence
that we, the said Robert Valentine Leach and Thomas William Willett, our
executors, administrators, and assigns, or such others as we, the said Robert
Valentine Leach and Thomas William Willett, our executors, administrators,
and assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF TIN PLATES AND TERNE OR LEADED
PLATES, AND IN THE APPARATUS CONNECTED THEREWITH," upon the condition
(amongst others) that we, the said Robert Valentine Leach and Thomas
William Willett, our executors or administrators, by an instrument in writing
under our, or their, or one of their hands and seals, should particularly
describe. and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
to:·
NOW KNOW YE, that we, the said Robert Valentine Leach and Thomas
William Willett, do hereby declare the nature of our said Invention, and in
what manner the same. is to be performed, to be particularly described and
ascertained in and by the following statement:-
At present, after coating the plate in the tin or terne pot and brushing it,
it is the common practice to dip the coated plate in the wash pot, and after-
wards, for the purpose of regulating the weight of the coating, to dip it in the
grease pot, as is well understood. The defects of this. arrangement are, that as
the plate is dipped in and removed from the wash pot by hand only, that

page_text: therefore the weight of the coating upon the plates is necessarily very irregular,
so that even were the periods of their subsequent immersion in the grease pot
strictly equal and uniform in duration, the result would yet not be a uniform
weight of coating upon each plate, but the operation of dipping in the grease
pot is itself performed by hand only, and the period of its duration is itself
irregular. The result in practice is found to be that the weight of the coating
upon the plates varies considerably. The process is also open to this further
great objection, that not only is there a want of uniformity in the weight of
the coating upon the plates, but also from the manner in which the operation
is conducted, the coating itself is very unequally distributed over the surface
of each plate. The molten coating runs from the upper towards the lower
edge of the plate, and in practice the result is that the thickness of the coating
gradually increases from the top edge to the bottom, where it accumulates in a
mass, which has afterwards to be removed by the process of listing.
Now, the object of our Invention is to obtain a more uniform weight of
coating upon every plate, and also more evenly to distribute that weight of
coating over its entire surface. For this purpose, we employ suitable racks,
capable of holding at one time several plates at uniform distances apart.
These racks are so constructed that by suitable mechanical means acting in
connexion with some motive power (by preference water), they can be lowered
into or raised from both the wash pot and the grease pot at determined speeds..
Immediately after the operation of brushing, a fixed number of plates are
placed in one of these racks, which is then immersed in the wash pot; here it
remains for a brief interval, and is then raised above the surface of the coating
metal; the effect is that every plate in the same rack thus receives a like
weight of coating, and as the operation can be almost exactly repeated, any
number of plates may in like manner receive an equal weight of coating.
The plates thus coated are then in the same or a similar rack, and by similar
mechanical means, simultaneously dipped in the grease pot, and, as every plate
in the rack has been subjected to an exactly similar treatment, it will be found
that each has upon it a like weight of coating, but in order that this like
weight of coating upon each plate may be evenly and uniformly distributed
over its surface, we so determine the speed at which the rack is immersed in
and withdrawn from the grease pot, that the rack enters the grease pot at a
gradually increasing speed, and leaves it at a gradually decreasing speed,
and we can thus subject the thicker coating which was left upon the lower
portion of the plate as it came from the wash pot for a longer determined
period of time to the action of the grease pot, and by properly proportioning

page_text: this varying speed to the size of the plate and the temperature of the coating
metal, we can obtain a very even coating.
We would here remark that the "mechanical means" that we prefer to
employ (although we do not in any way confine ourselves thereto) is a simple
lever, to one extremity of which the rack is suspended by chains, while the
other extremity is acted upon by a cam of suitable form.
. We would also remark that in the case of the wash pot we do not consider.
it as very material whether the rack be immersed before or after it is filled, or
that the speed of the immersion or withdrawal be uniform or gradually
increasing, or otherwise, but we prefer to fill the rack before we immerse it in
the wash pot, and to withdraw it at a gradually decreasing speed.
We would also mention that for some descriptions of plates the wash pot
may conveniently be made of such size as to allow of a depth of grease above
the molten metal sufficient for the purposes of a grease pot, but of course in
this arrangement the rack. carrying the plates must be withdrawn from the
superincumbent grease at a gradually decreasing speed.
The following is another arrangement, by which also we obtain an equal.
distribution of the coating upon each plate :-The plates as they come from.
the wash pot are placed horizontally at even distances apart in a suitable rack;
this rack when filled is immersed in the grease pot, where it is allowed to
remain stationary for about one minute; it is then by suitable mechanical
means caused to rotate at a determined speed, and for a determined time upon
a vertical axis; this speed is so proportioned to the size of the plate and the
temperature of the metal, that by reason of the centrefugual force a greater or
less portion of the superfluous coating is thrown off from the edge of the plate,
and the time and speed of rotation are proportioned according to the quantity
of the coating which it is desired to remove. Before withdrawing the rack
from the grease pot, it is allowed to remain stationary for about another minute,
in order that the coating metal may equalize itself upon the surface by flowing
from the edges towards the centre of the plate, which it is disposed to do in
consequence of that part being the lowest portion.
For the commoner descriptions of tin and terne plates, where the weight of
the coating metal is small, we determine the weight of the coating metal upon
each plate by means of a grease pot, either such as is in common use or (which
we prefer) similar to that herein-before first described, and we afterwards
arrange the plates in a suitable rack in a
position nearly horizontal, and then
immerse them again in a grease pot. In this case the holding rack is not
caused to rotate, but remains stationary in the grease pot for a determined

page_text: time; the effect of this operation is greatly to improve the appearance of the
plate by equalizing the coating upon its surface.
In arranging the plates in the rack for this last operation, we take care to
place that edge of the plate which was before downward in the grease pot a
little higher than the other edge, so that the coating has a tendency to flow
from the thicker to the thinner portion.
Our last improvement consists in a new apparatus for listing. This consists
in the employment of a flat metal plate (by preference of copper smooth upon
its surface and tinned); this plate is placed at an inclination of about thirty
degrees, and is heated by a suitable flue.
The plates are arranged in a suitable rack, and the edge that is to be listed
rests upon the tinned copper. The effect is to heat the edge of the plate, and
remove the superfluous portion of coating metal, which then runs from the
inclined surface of the plate, and by this means we effect a more even and
accurate listing.
In witness whereof, we, the said Robert Valentine Leach and Thomas
William Willett, have hereunto set our hands and seals, this Fifteenth
day of November, in the year of our Lord One thousand eight hundred
and fifty-nine.
ROB. VALENTINE LEACH.
(L.S.)
THOMAS WILLIAM WILLETT. (L.S.)
Vitness the signatures of the above-
named Robert Valentine Leach
and Thomas William Willett,
C. H. PADDISON.