IMPROVEMENTS IN COATING METALS
Year: 1864

page_text: LETTERS PATENT to Edmund Morewood, of Cheam, in the County of
Surrey, for the Invention of "IMPROVEMENTS IN COATING METALS."
PROVISIONAL SPECIFICATION left by the said Edmund Morewood at the
Office of the Commissioners of Patents, with his Petition, on the 24th
December 1864.
I, EDMUND MOREWOOD, of Cheam, in the County of Surrey, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN COATING
METALS," to be as follows:-
This Invention has for its object improvements in coating metals.
One part of my Invention consists in making one or both of the sides, or a
portion of the side of that which is called the flux box in the process of
coating with melted metal moveable, so that whilst the ends of such box
remain in their place, that portion of one side which is in contact with the
melted metal is close to the same part of the other side, instead of being an
inch or more apart, as heretofore. When a sheet is passing down through
the flux box and reaches the lower edges of the sides, it causes one or both to
open by a very slight pressure, but they close again as soon as it has passed.
My object is to prevent (as far as possible) flux or foreign matter from
travelling with or after the sheet out of or beyond the flux box.

page_text: Another part of my Invention has for its object to prevent (as far as
possible) the rollers (in the melted metal or flux) between which pieces of
iron or copper travel in the process of coating from collecting oxide or dirt, or
other matter which it is not desirable that they should transmit to the sheets
or pieces of iron passing between them. In order to avoid this I use rollers
which have hollows or grooves around them, of such depth that oxide, dirt,
or undesirable matters may collect in them. The projections of these rollers
are arranged opposite to one another, so as to avoid making any grooving or
indentation on the surface of the piece of metal passing between them. With
the same object I sometimes arrange the rollers so that although the sheets
or pieces in process of coating pass between two rollers, yet such rollers are
so placed that one of the pair does not bite upon or touch the other; but the
first end of the sheet or piece after touching or pressing with its under surface
upon one roller travels on until its upper surface reaches and presses upon
the under side of the further roller of the pair, or vice versa.
And I use
guides in order to conduct the sheets in the desired direction. And by com-
bining such guides with rollers or forms of iron, and the adjustment of either
or both by screws, or otherwise, I cause the sheets or pieces to have a some-
what in-and-out travel under the coating metal, and cause them to make their
exit straight and flat as I require them.
Another part consists in placing finishing rollers (which work in contact
with melted metal, or with the flux on its surface at the side where the sheet.
leaves the coating metal) so that there shall be a supply or channel of melted
coating metal above the nip or centre of such finishing rollers when the sheet
is passing between them. Such finishing rollers when revolving with their
tops above the surface of the melted metal assist in carrying over scruff or
foreign matter from and out of this channel. And from this channel or
supply the sheets take a finishing coating. On the outside of each roller of
the pair the surface of the coating metal is covered with suitable flux or
matter. Sometimes (especially if I wish to work fast) I have a suitable flux
on the surface of the coating metal which is in the channel between the rollers.
At other times I leave the channel of coating metal between the rollers
uncovered, or covered with some other matter than flux. In such case I
work more slowly, but use less flux. Sometimes I place a small oblong box
shaped like a flux box (open at the top and bottom, but narrowing towards the
middle or lower edge), in the channel of coating metal between the finishing
rollers. Into and through this box the sheet passes after leaving the nip of
the finishing rollers in making its final exit from the coating metal. And I
arrange the lower part of the box so as to prevent scruff or foreign matter

page_text: from entering it as far as possible. I also place a similar box for the travel
of the sheet below the finishing rollers, so that passing along within such box
the sheet has a road through comparatively pure and clean metal.
Another part of my Invention consists in making the diameter of these
finishing rollers five inches or upwards, so as to be able to regulate the depth
of the supply or channel of melted coating metal, or of the flux or matter above
it. And to give steadier or more upright motion to the sheets. And to
throw more heat upon them as they emerge into the open air. I also attach
a scraper or brush to the finishing rollers in order to keep them clean and as
free from scruff and foreign matter as possible.
Another part of my Invention consists in using tooth wheels and friction
wheels combined, for the purpose of giving steady and even motion to the
rollers of the coating machine.
Another part of my Invention consists in using a copper bath and copper
rollers for the preparatory cleansing liquid or flux through which the sheets
or pieces pass before they enter the melted coating metal.
Another part consists in the use of a pan or vessel containing sand or other
substance which is a bad conductor of heat, placed upon or immersed in the
coating metal, so that the sheets in process of coating pass under such pan or
vessel of sand, or between it and the outer bath, by which I retain heat,
and keep the temperature of the coating metal more steady, and prevent
evaporation from its surface. This inner vessel is so shaped as not to interfere
with the arrangement of the rollers or coating instruments.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edmund Morewood in the Great Seal Patent Office on the
24th June 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
MOREWOOD, of Cheam, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by ler Letters
Patent, bearing date the Twenty-fourth day of December, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Edmund Morewood, Her special licence that I, the said Edmund
Morewood, my executors, administrators, and assigns, or such others as I, the
said Edmund Morewood, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times there-

page_text: after 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
COATING METALS," upon the condition (amongst others) that I, the said Edmund
Morewood, my executors or administrators, by an instrument in writing under
my, 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.
NOW KNOW YE, that I, the said Edmund Morewood, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:―
This Invention relates to improved apparatus employed as herein-after
described in the process of coating metals.
In the operation of coating sheets or plates of metal with melted coating
metal it is very important (especially when one kind of flux is used on the
surface of the coating metal on the entrance side of the bath of melted metal,
and another kind of flux or no flux at all on the exit side), to have such an
arrangement as to free the surface of the plate or sheet from any of the flux
which may cling to it as it passes into the coating metal from the flux on the
entrance side, and to prevent (as far as possible) any flux or foreign matter
from travelling with the sheet under the coating metal, and to that part of
the bath from which the plates make their exit.
In order to accomplish this I use improved apparatus for introducing the
sheets or plates into the bath of coating materials. I make the lower part of one
or both of the sides of the vessel, which is known by the name of the flux box,
moveable, or turning on a hinge in such a position that when at rest and
closed one point of each side of such lower part touches a point of the other
side of such flux box as shown in the annexed Drawings, where a (Figure 1)
represents the flux box, 6 the side that is pendent or hinged at the point c.
The points which touch are below the surface of the coating metal, and in
practice I use them so far below, that when I put the plates into the flux box
such plates are immersed in the coating metal when resting on the bottom of
the flux box, and if such flux box be in a dipping bath of tin or terne metal
for ordinary sized plates, they will be wholly immersed in such metal, but if
the coating metal be other than tin or terne metal, say, zinc, or the sheets of
very large size, such sheets may be only partially immersed in the coating

page_text: metal when they begin to pass out through the moveable part of such flux
box, the hinged or moveable part of the side is also so far below the sur-
face of the coating metal that the upper portion which is stationary is
sufficient to confine the flux within the flux box. When the sheets are
pressed down through the bottom of the flux box they make their entrance
into the melted metal by pushing the moveable side or sides sufficiently apart
from each other to allow them to pass, or these sides may be pushed apart by
by means of a lever as shewn in the Drawing at d, the lever may be worked
either by hand or by a weight suspended from the lever, which should be so
regulated that the weight and pressure of the plates on the moveable sides
would cause those sides to part asunder, and allow the plates to enter into the
melted metal. By this means I am enabled to retain the plates a short time
within the flux box, and under the coating metal. To enable the plates or
sheets readily to push apart the moveable side or sides of the flux box I make
the bottom edges of such moveable side or sides of half round wrought iron,
the somewhat rounded part being presented to the surface of the plate as it
passes out or brushes by it. Instead of making the side or sides moveable as
above described the bottom of the box may be made moveable, and be so
arranged as to act like a trap or valve, and so allow the plates or sheets to
enter the bath.
In coating iron with tin or lead, or zinc, or their alloys in a melted state
by means of rollers, the sheet in passing through the flux into and under the
coating metal is apt to draw down with it some of the flux or foreign matter,
and either to deposit the same on the rollers as it passes between them,
especially between the first or second pairs, or to get such foreign matter more
or less pressed on to the surface of the iron by the nip or bite of such rollers.
In order to avoid this as much as possible I employ my improved apparatus
for transmitting or passing the plates or sheets through the bath of coating
materials to the part where they make their exit, or are extracted.
I make flutes or grooves in the pairs of rollers between which the sheets
first pass after being immersed under the surface of the coating metal, such
grooves being of the depth of about of an inch, and to the breadth of
about 2 inches, with an interval of about one inch between each groove or
flute, the diameter of such rollers from top of projection to top of projection
being 4 inches. These flutes are made to circle round the rollers, and the
flutes and projections of each roller of the pair are so arranged that when
the pair are revolving, the projections of one of the pair are opposite to
and meet the projections of the roller of the other pair, and the grooves
and flutes are opposite to and meet the grooves or flutes in the "other

page_text: roller of the pair. The fluted or grooved rollers which are supported in
bearings, only bite or touch the sheets where the projections of each roller of
the pair meet one another, and no pressure is given to those parts of the
sheets which pass between the grooves or hollows.
Another mode by which I obtain the same object is as follows:-I arrange
the first two pairs of rollers as shewn in the Drawings at Figure 2, so as to
effect what may be termed an alternately over and under action upon the sheet
or plate. By this means I avoid giving pressure at the same time to both the
upper and under side of the same part of the sheet passing between the pairs
of coating rollers, although the revolution of such pairs of rollers causes the
plate to travel when passing between them in the desired direction; and I
ensure the right travel of the sheets by means of guides.
My improved apparatus for providing properly for the exit or extraction of
the plate or sheet I arrange as shown in Figure 3, where a, b, are the last or
finishing pair of rollers (working in contact with coating metal) through
which the sheets or pieces of iron in process of coating make their exit from a
bath of coating metal. The rollers are so arranged that they work under the
surface of the melted coating metal at such a depth (although their tops are
above the surface) that the coating metal rises above the centre or nip of the
finishing rollers so far as to form a supply or channel of melted coating metal
above the nip or centre of such rollers, and through that channel the sheets
pass out of the bath after leaving the nip of the finishing rollers. By passing
the sheet or plate out through a channel of coating metal after leaving the
nip of the finishing rollers, those parts which may have been imperfectly
covered or which may have had their surfaces of coating too much thinned in
passing through the nip of the finishing pair of rollers, obtain a further
coating of the melted metal.
Another advantage attending this arrangement is, that the finishing rollers
in their revolution through and out of the melted metal bring up (especially
in the case of tin) and carry over as they revolve that which is technically
called "scruff" upon their upper surfaces, and as such upper parts of the rollers
in revolving re-enter the coating metal on the side away from the nip they
'leave the "scruff" on the surface of the bath of melted metal on the outer
side of each roller. The "scruff" can easily be collected and withdrawn
from that part by means of a flattened rod of iron or other suitable means.
By this arrangement the rollers act the part of scavengers to the channel of
'coating metal which is between them and immediately above their nip.
It should be observed that it is not advisable in coating sheets or plates of
metal to keep a flux on the surface of this channel of melted coating metal

page_text: unless the means of removing it readily from the surface of the coated plates
are provided.
On the exterior side of the finishing rollers a, b, I keep a suitable flux, as
tallow or grease for tin or tern metal, as represented in the annexed Drawing
at w, w. In some cases if I have the means of removing the flux from the
surface of the coated sheets readily, I use a flux upon the channel of coating
metal, as such flux enables me to cause the sheets to travel out rapidly and
bring out a thinner coating of metal on their surface than if the sheets came
out through clear metal.
In coating with tin or terne metal, when I wish to prevent the sheets
bringing out on their surface any flux as grease as they emerge or are
extracted from the channel of such melted metal, I use no flux on the channel
of such melted metal between the finishing rollers, and I keep the surface of
the channel about two inches above the nip or centre of those rollers. In
coating with ziuc I use a layer of fine sand, slightly damp, on the channel of
melted zinc between the finishing rollers, and muriate of ammonia on the
exterior side, but if the sheets in process of coating follow one another steadily
and rapidly I work with such channel of melted zinc uncovered, and in that
case I usually employ on the exterior sides of the said finishing rollers a flux
of sal ammoniac on the surface of the melted zinc.
It must be specially observed that in coating with tin it is important, as
before mentioned, for the appearance of the plates in process of coating, that
the melted metal through which they make their exit should be as free from
"scruff" or foreign matter as possible.
In coating with tin, when I wish to make rapid work in order to keep the
channel of melted metal through which the sheets emerge after leaving the
nip of the rollers clear of scruff and foreign matter, I use in addition to the
rollers which act as scavengers, as herein-before described, an oblong box c,
made of wrought iron, shaped as shewn in the annexed Drawing, open both
at the top and bottom in the said channel of melted coating metal, the lower
ends of which converge. The sheets in process of coating pass up from the
nip of the finishing rollers into and through the narrow opening at the bottom
of this oblong box, being guided into it by means of small guide pins d, about
an eighth of an inch in diameter, projecting outwardly below the bottom of
the box so as to insure the entrance of the sheets into such box. I make
such oblong box at the end where the sheets enter of about at of an inch in
width, extending lengthways along the oblong box or trough which widens
out towards the top, where the opening is from about an inch and a half to two
inches wide, and I make the side or sides of such box so as to yield readily to

page_text: the pressure which may be caused by sheets of more than ordinary thickness
passing between them; if it be found that there is more impurity in the coating
metal than is got rid of by the last-described modes, I also place an oblong
box of like character between the rollers which are next below the finishing
rollers. When I use finishing rollers with a channel of coating metal above
their nip, as herein-before described, I make such rollers of about 6 or 8
inches diameter, so that they may form a kind of heated wall above the
surface of the melted metal which does not rise above the nip of the rollers to
nearly the level of their upper surfaces. By using rollers of this diameter I
obtain the advantage of passing the sheets or plates on their emerging from
the bath of coating metal into a stratum of heated air, this assists the melted
coating metal in arranging itself evenly on the surface of the sheet or plate
and gives more opportunity to the superfluous melted metal to quit the sheet
or plate as it makes its exit, and to give a steady and upright motion to the
sheets or plates. In practice I use these finishing rollers hollow. I also use
guides and guiding rollers e, e, as shown in the annexed Drawing, so shaped
and placed as to cause the plates to enter between the finishing rollers less
curved. These rollers are capable of adjustment by screws or otherwise.
In order effectually to prevent the rollers from retaining on their surface
scruff, oxide, flux, or foreign matter which they might place on the surface of
the plates in process of coating as they pass up between the nip of such
finishing rollers, 1 employ scrapers or brushes f, f, placed as shown in Figure 8
in the Drawing annexed.
As it is most important (especially when coating with melted lead or tin)
that the motion of the finishing rollers should be very steady and even, and
that there should be as little jolt or jar or waving of the coating metal in the
channel as possible, I use a tooth or cog wheel a, working in combination
with a friction wheel 6, as shown in Figure 4 of the annexed Drawings, the
friction wheel in this case makes the motion of the tooth or cog wheels steady
and regular.
In the Specification of Patents granted to me and bearing date the 14th
January 1863, No. 123, and 7th August 1868, No. 1958, I have described a
preparatory flux or cleansing fluid bath through which the sheets travel before
entering the first coating metal bath in order to make such sheets or pieces in
a fit state to take the coating metal readily whether such sheets are to be
coated by the dipping or roller process.
I have ascertained that in using such preparatory flux in coating metals a
great improvement is effected by employing a vessel made of a metal negative
to tin, such as copper instead of iron, for the purpose of containing such pre-

page_text: paratory flux, and when I use rollers to assist the transmission of the sheets
through such preparatory bath of flux or cleansing fluid or thence to the
coating metal, I make those rollers of copper in the place of iron, as in
practice I find that the cleansing preparatory fluid salts, as herein-after.
described, act with much better effect in preparing the surface of the sheets
of iron to be coated if they are contained in a copper vessel, or if they come in
contact with copper only, than if they are contained in an iron vessel and come
in contact with iron. When I have filled the copper pan three-quarters full
with the preparatory solution herein-after described, I cause the sheets to
enter the said fluid, and then I add from time to time sufficient chloride of
copper to cause the plates when they emerge, to have a slight film of the
copper or salt of copper on their surfaces. Wood or other material may be
used in making this vessel if copper forms such portion as to come in contact
with the cleansing fluid, but I use no metal positive to tin in that position.
In coating with tin, lead, or the alloys of tin and lead, I use as the prepa-
ratory fluids or flux in the copper pan a solution of chloride of tin, that is,
tin dissolved in the muriatic acid of commerce until the acid is, in ordinary
parlance, completely neutralized by the tin, and I add thereto two quarts of
water to each pint of solution. When coating with zinc I use a solution of
chloride of zinc, adding thereto 15th by measure of sal ammoniac in solution,
and also adding to each pint of this solution two quarts of water. When
coating with an alloy of tin and zinc, or of tin, lead, and zinc, I use the same
preparatory liquid or fluid flux as in the case of coating with tin, lead, or the
alloys of tin and lead, I keep these preparatory fluids at a heat of about
150 degrees of Fahrenheit.
In employing for coating metals a bath of melted metal as above described,
I have found that it is a great improvement to use a pan or vessel which I
make of crucible earthenware capable of bearing the heat, and place it as
shown at Figure 2 of the annexed Drawing, letter z, so that it rests upon and
penetrates more or less into and under the surface of the coating metal. This
additional pan is filled with sand or other matter which being a slow conductor
of beat causes the heat to be retained in the bath of heated metal, and
prevents as far as possible the loss of heat by radiation from the surface. By
thus retaining the heat the necessity of applying a high degree of heat to the
outside of the bath, and the loss of metal by evaporation are to a great extent
obviated, the larger bath containing the pan is not destroyed so quickly, and I
am able to keep the heat throughout the entire quantity of melted metal
equably at the requisite temperature.
In the annexed Drawing the inside pan z, used for the sand, is so placed in

page_text: relation to the rollers or guiding frame that the sheets can have a long travel
through coating metal, and at the same time the pan is out of the way of the
rollers and guiding frames. This pan may be readily applied to other descrip-
tions of vessels used for containing coating metals.
Having now described my several improvements and the manner of
carrying the same into practice, I would have it understood that what I claim
is, first, the general combination of parts forming the apparatus combined and
arranged as herein described and shown in the Drawings annexed.
Secondly, the apparatus used for introducing the sheets or plates into the
bath, and also that used for transmitting them through the bath, and also
that used for providing for their exit or extraction from the bath ȧs herein
described.
Thirdly, the use of a copper bath for containing the preparatory fluid flux,
and also the copper rollers, whereby I convey such sheets through the pre-
paratory fluid flux bath as described, or between it and the coating metal, as
herein described.
Fourthly, the use of an inside bath or pan containing sand or other non-
conducting matter applied as herein described.
In witness whereof, I, the said Edmund Morewood, have hereunto set
my hand and seal, this Twenty-third day of June, in the year of our
Lord One thousand eight hundred and sixty-five.
EDMUND MOREWOOD.
L.S.)