IMPROVEMENTS IN COATING METALS, AND IN APPARATUS EMPLOYED THEREIN
Year: 1878

page_text: LETTERS PATENT to Edmund Morewood, of Llanelly, in the County of Caer-
marthen, Tin Plate Manufacturer, for the Invention of "IMPROVEMENTS IN
COATING METALS, AND IN APPARATUS EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said Edmund Morewood at the
Office of the Commissioners of Patents on the 28th January 1878.
F
EDMUND MOREWOOD, of Llanelly, in the County of Caermarthen, Tin Plate
Manufacturer.. "IMPROVEMENTS IN COATING METALS, AND IN APPARATUS EMPLOYED
THEREIN."
"
The main object of this Invention is to produce tin or terne plate at one operation,
or by a continuous passage from the entrance side of the apparatus to the exit
without any intervening hand manipulation, but there are parts of the Invention
which are applicable when the process is not continuous, and also when coating
metal other than tin is employed..
The apparatus which I employ is similar to some extent to that shewn and
described in the Specification of a former Patent granted to me, No. 1958, in the
year 1863, but with improvements by which the process is brought under control,
and which enable me to produce perfect plates when working with fluxes, which
require a high temperature for the tinning operation.
The plates are caused to descend into the tinning pot through flux. They are
conveyed through the molten metal and are delivered on the exit side between
finishing rollers, which revolve in grease supported on the surface of the melted
metal.
The pot or vessel containing the metal is divided into parts (but with a passage
for the plates to pass) so that the coating metal may be maintained in one part at
the high temperature requisite for coating, and in another part at the much lower
temperature to which it is desirable that the plate should be reduced before it
arrives at the finishing rollers.

page_text: I provide for the regulation of the temperature in the cooler part of the pot by
forming flues through which either hot or cold air may be passed at pleasure; or by
other analogous means I control the temperatnre of the cooler part of the metal
pot.
On the exit part of the pot I have the finishing rollers revolving in grease con-
tained in a bath or vessel open at the bottom, and dipping into the melted metal
in this the cooler part of the metal pot. I provide for the regulation of the tem-
perature in the bath or vessel containing the finishing rollers. One mode is by
making passages through or around it, through which cold air or other fluid may
be passed.
And the same passages are available for the passage of hot air or
fluid for warming the apparatus at the commencement of working, or in other
analogous way I regulate the temperature of the finishing bath or vessel.
I also maintain a proper temperature and quality of grease in this bath or vessel
by supplying cool grease to it; this may be done through a pipe descending nearly
to the surface of the melted metal, whilst the hotter grease is drawn out into a
receiver by a passage provided for the purpose.
In some cases I form in connection with the bath or vessel containing the finishing
rollers an extension end or side chamber to contain cool grease.
The end or side chamber should be so arranged that the grease which it contains
does not stand over the melted metal, and a communication is made near the
bottom between the main compartment of the bath or vessel and its side chamber.
In order to remove impurities which are liable to accumulate at or near the
surface of the molten metal where the grease rests in contact with it, I provide an
aperture in the side of the pot at this part, which can be opened or closed at
pleasure.
I employ in the finishing bath or vessel several (say three) pair of finishing
rollers, and I supply melted coating metal to some or all of these by providing
troughs beneath the rollers, which are kept full of metal. This metal may be drawn
from a small receiver immersed in the grease to keep the metal melted.
In some cases I cause the plate as it rises in the finishing bath or vessel to pass
between two surfaces of metal placed near together so as to leave but a narrow
channel between them for the plate to pass, and as the plate rises between these
surfaces I cause it to meet a trickle or descent of molten metal descending from a
receiver, such as that mentioned above. The plate must be caused to pass between
finishing rollers after it has been between these metal surfaces.
The employment in the manner described of clean melting coating metal in the
finishing operation is of great importance when a high heat is maintained in the
tinning pot, as otherwise the plates are liable to be injured by scruff, which the
plates will bring forward with them.
When fluxes, such as chloride of zinc, are used on the entrance side a lower
temperature will suffice, and less scruff is formed, but the use of fluxes of this
description is objectionable."
It will be seen that in the process as above described, the plate is never exposed
to the air from the time that it enters the apparatus until it issues a finished
plate. I however in some cases allow the plate to pass through flux in going
from the hotter to the cooler part of the tinning pot.
To allow the plate to issue into the air, or even into the flux vapour as is
suggested in the Specification of my former Patent already referred to is objection-
able, but if it be permitted the conveying rollers which are not covered with the
metal or flux should be provided with troughs containing melted coating metal, so
that their surfaces may be constantly bathed with it, which will tend to lessen the
evil arising from the exposure.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edmund Morewood in the Great Seal Patent Office on the 27th
July 1878.
EDMUND MOREWOOD, of Llanelly, in the County of Carmarthen, Tin Plate
Manufacturer. "IMPROVEMENTS IN COATING METALS, AND IN APPARATUS EMPLOYED
THEREIN."
The main object of this Invention is to produce tiu or terne plate at one operation,
or by a continuous passage from the entrance side of the apparatus to the exit
without any intervening hand manipulation, but there are parts of the Invention
which are applicable when coating metal other than tin and terne is employed.
The apparatus which I employ is similar to some extent to that shewn and
described in the Specification of a former Patent granted to me, No. 1958, in the
year 1863, but with improvements, by which the process is brought under control,
and which will enable ine to produce perfect plates when working with fluxes which
require a high temperature for the tinning operation.
The plates are caused to descend into the tinning plot through flux; they are
conveyed through the molten metal, and are delivered on the exit side between
finishing rollers, which revolve in grease, supported on the surface of the melted
metal.
°
The pot or vessel containing the metal is divided into parts (but with a passage
for the plates to pass) so that the coating metal may be maintained in one part at
the high temperature requisite for coating, and in another part at the much lower
temperature to which it is desirable that the plate should be reduced before it arrives
at the finishing rollers.
I provide for the regulation of the temperature in the cooler part of the pot by
forming flues through which cold air or other fluid of a cooling nature may be
passed at pleasure; or by other analogous means I control the temperature of the
cooler part of the metal pot.
On the exit part of the pot I have the finishing rollers revolving in grease con-
tained in a bath or vessel open at the bottom, and dipping into or standing over
the melted metal in this the cooler part of the metal pot. I provide for the
regulation of the temperature in the bath or vessel containing the finishing rollers.
One mode is by making passages through or around it, through which cold
air or other fluid may be passed, and the same passages are available for the
passage of hot air or fluid for warming the apparatus at the commencement of
working; or in other analogous way I regulate the temperature of the finishing
bath or vessel.
.
I also maintain a proper temperature and quality of grease in this bath or vessel
by supplying cool grease to it; this may be done through a pipe descending nearly
to the surface of the melted metal, whilst the hotter grease is drawn out into a
receiver by a passage provided for the purpose.
In some cases I form in connection with the bath or vessel containing the finishing
rollers an extension end or side chamber to contain cool grease.
The end or side chamber should be so arranged that the grease which it contains
does not stand over the melted metal, and a communication is made near the
bottom, and when convenient at other points also, between the main compartment
of the bath or vessel and its side chamber.
In order to remove impurities which are liable to accumulate at or near the.
surface of the molten metal where the grease rests in contact with it I provide an
aperture at the part which can be opened or closed at pleasure.
I employ in the finishing bath or vessel several pair of finishing rollers, and I
supply inelted coating metal to some or all of these by providing troughs beneath

page_text: .
the rollers, which are kept full of metal. This metal may be drawn from a small
receiver immersed in the grease to keep the metal melted.
In some cases I cause the plate as it rises in the finishing bath or vessel to pass
between two surfaces of metal placed near together, so as to leave but a narrow
chanuel between thein for the plate to pass, and as the plate rises between these
surfaces I cause it to meet a trickle or descent of molten metal descending from
a receiver such as that mentioned above. The plate must be caused to pass between
finishing rollers after it has been between these metal surfaces.
The employment in the manner described of clean melted coating metal in the
finishing operation is of great importance when a high heat is maintained in the
tinning pot, as otherwise the plates are liable to be injured by scruff which the
plates will bring forward with them.
When fluxes, such as chloride of zinc are used on the entrance side, a lower
temperature will suffice, and less scruff is formed, but the use of fluxes of this
description is objectionable.
It will be seen that in the process as above described the plate is never exposed
to the air from the time that it enters the apparatus until it issues a finished plate.
I however in some cases allow the plate to pass through flux in going from the
hotter to the cooler part of the tinning pot.
To allow the plate to issue into the air or even into the flux vapour, as is
suggested in the Specification of my former Patent already referred to, is
objectionable, but if it be permitted the conveying rollers, which are not covered
with the metal or flux, should be provided with troughs containing clean melted
coating metal or clean liquid flux, so that their surfaces may be constantly bathed
with it, which will tend to lessen the evil arising from the exposure.
In order that my Invention may be most fully understood, and readily carried
into effect, I will proceed to describe the Drawings hereunto annexed, which
Drawings I may remark are similar to the Drawings which I annex to the
Specification of another Patent granted to me bearing even date with the Patent
of which this is the Specification, the said Drawings being there employed to illus-
trate points of Invention different from those which are claimed under the Patent
to which this Specification applies.
Figure 1 is a longitudinal section of apparatus intended especially for the manu-
facture of tin plate at one operation, but also very suitable for the manufacture of
terne plate.
A, A¹, is the pot in which the coating metal is contained; it is divided into two
parts by the air space or flue B, which serving as a heat barrier obstructs the
passage of heat from one part of the pot to the other, and adímits of the metal in
the part A being kept at a much higher temperature than the metal in the part A¹,
although there is a passage connecting the two parts of the pot of sufficient width
to give ready passage to the plates to be coated.
The pot is set in brick work, as is usual, and beneath the part A a fire-place is
formed for heating the pot, and it is so arranged that the heat from this fire sball
not reach the bottom and outer sides of the part A', beneath which however another
fire-place is formed, the use of this second fire being to warm the part A¹ when
commencing work after the apparatus has been allowed to get cold.
At other times and when in regular work no fire is used in the fire-place under
the part A¹, but a current of cold air is allowed to pass through it to the chimney
whenever the temperature of the part A¹ of the pot tends to rise higher than the
workman desires, and this current of air carries away heat from this part of
the pot.
Air currents can also be allowed to pass to the chimney through the space or.

page_text: C
flue B, and through the similar space or flue B¹ these air currents can be controlled
by means of dampers.
Other means may be taken to cool the end A¹ of the pot when requisite, but I
find the application of air currents the most convenient.
C, C, are cast-iron frames introduced into the part A of the pot at a short
distance from the sides. These frames carry the bearings of the metal coated
rollers D, D, which are geared together by spur wheels contained in the spaces
between the frames C and the sides of the pot. The arrangement of this driving
gear is indicated by dotted lines.
The part A¹ of the pot contains other rollers. D¹, D¹; their bearings are held in
frames similar to the frames C, but not shown in the Drawing; these rollers are
driven at the same surface speed as the rollers D by gearing indicated in dotted
lines.
.
E is the bath or vessel in which is contained the finishing grease, usually palm
oil, or a mixture of palm oil and tallow. A plan of this bath or vessel is given in
Figure 2. Within the bath or vessel E the frames F, for holding the bearings
of the rollers G, are received and secured; dotted lines show the gear for driving
these rollers.
His the entrance flux box, its lower and smaller end dips into the metal con-
tained in the part A of the pot. The flux box H is charged with a flux consisting
as I prefer of 67 parts of resin, 23 parts of tallow, and 10 parts of palm oil. This
flux is referred to, and claims relating to its use under certain conditions are made
in the Specification of another Patent granted to me, and bearing even date with
the Patent of which this is the Specification.
Within the flux box H there are stationary guides H¹, H', and in connection
with these there are other guides H2 which are moveable about centres H2*, and springs
or weights tend to close the lower ends of the moveable guides H2 against the fixed
guides H¹; there are thus four spaces in the flux box H shown in the Drawing
between the fixed and the moving guides, and each of these spaces is adapted to
hold a plate to be coated. In working the apparatus each of these spaces in turn
receives a plate from the hand of the workman, who as he introduces each plate
moves the guide H2 corresponding to the space which he is charging, in order that
the plate which the space already contains may be able to pass out, and with the
new plate he pushes down the plate which is to pass out until the first pair of the
rollers D take hold of it. By this arrangement the plates are detained in the flux
long enough to bring them to a suitable state and temperature to enter the coating
metal.
The number of plates which the flux box is adapted to retain at one time may
be varied, four however is a suitable number to ensure proper preparation when
working rapidly. The pot is filled with metal so as completely to cover the first
pair of rollers D, and so that these rollers may be clear of the scruff or impurity
which floats upon the surface of the molten metal. The plates are carried forward
by the rollers D, aided by. the guides C¹, C', which are fixed to the side frames, and
in their passage the somewhat highly heated metal in the part A of the pot takes
on to the plate and gives to it a sound coating. The plate then passes on through
the narrow opening left for it into the cooler part A' of the pot; the temperature of
this plate is thus rapidly reduced and the coating upon it is brought to a state fit
for finishing. If any of the scruff which forms in the hot end of the pot should be
carried forward with the plate into the part A¹, a large portion of it will rise imme-
diately to the surface of the metal, and the flue B' acting as a barrier will prevent
it reaching the finishing grease contained in the bath or vessel E.
The plate
emerging from the molten coating metal enters the finishing grease, and is carried
up through it by the coated rollers G.
The distances between these rollers can be adjusted by means of regulating screws
acting through springs, and in the case of the uppermost rollers where it is necessary
that the adjustment should be completely under control, the screws act upon the

page_text: bearings of the roller through spring levers. Beneath the uppermost roller's G,
troughs I, I, are fixed, and in these troughs clean coating metal is contained, and'
there is grease at the back of the rollers. This metal serves to keep the surface of
the rollers in good condition by washing off scruff or impurities which is brought
to them by the plates rising up through the grease from the coating metal.
A good
supply of metal given to the troughs I will cause the surfaces of the plates to be
well washed. The supply for the troughs I is drawn from supply vessels, which
however are not shown in the Drawings. There is a supply vessel for each trough;
it is arranged immediately in front of or behind the trough, as the case may be, and
is made long and narrow, so: that it may occupy but little room in the bath or
vessel E, which however may be made somewhat wider than the Drawings represent,
in order the better to accommodate these. supply vessels. The supply vessels are
immersed in the grease in the bath or vessel E, the heat from which serves to keep
the metal in the supply vessels in a molten state, and with the same object the
supply vessels may also be made deep, so that the lower part of the supply vessels
may dip down into the metal in the pot A¹, in order that the heat may be more
rapidly communicated from the metal in the pot to the supply vessels. Or in placé
of making the supply vessels of this great depth, they may be made with fins or
legs of metal long enough to become immersed at their lower ends in the metal
in the part A¹ of the pot. Slits or orifices in the sides of the supply vessel
allow the metal to flow out into gutters or pipes which lead the metal into the
troughs I. The supply can be regulated by slides covering the slits or orifices to a
greater or less extent.
This method of maintaining a supply of clean coating metal in a molten state
to the rollers or instruments in the finishing grease is referred to, and claims relating
to it are made in the Specification of another Patent granted to me, and bearing
even date with the Patent of which this is the Specification.
The extensions E, E, of the bath or vessel E overhang the pot, and they have
floors or bottoms, whereas tlie central part of the bath or vessel E is without a
bottom, the grease in it resting on the melted metal on the exit side of the coating
pot on one side of the pot a notch or recess is formed, to allow of the bottom of
the extension E¹ on this side to be at a somewhat lower level than the edge or flange
of the pot, so that occasionally, as herein-after explained, the pot may be filled suffi-
ciently full of metal to cause it to flow over the bottom of the extension E¹ on this
side, although the ordinary level at which I work is just beneath it.
Figure 3 is an elevation of the extension E¹; it is closed by a slide Ex, also seen
in section in Figure 4. The slide works in a groove, and a little packing of hemp
or hempen fabric may advantageously be placed in the groove, so that the slide may
work easily, and yet remain tight from the nature of the grease; however, but little
difficulty will be found in keeping the slide sufficiently tight, and any grease which
may leek out flows to a cistern in which it is collected.
When it is desired to draw off impurities from the surface of the metal beneath
the rollers G, metal is, put into the pot until the metal rises into the end E¹, to
which the slide Ex is fitted, and then the slide is slightly raised, so that the metal
may flow out beneath it, and with this metal grease settlings and impurities floating
on its surface will pass out. I prefer to arrange slides Ex in connection with the
extension at each end of the bath or vessel E; and I also provide other slides or
moveable partitions by which the extensions can be shut off from the body of the
bath or vessel E. By thus closing for a time the communication between the bath
and the connections, the warming-up of the apparatus when commencing to work
is facilitated, and the extensions or ends are rendered more accessible for cleaning.
As is seen in Figure 2, there is a pipe fitted with a tap in connection with each of
the extensions or ends E¹; they enter near to the bottom. One of these pipes is in
connection with a cistern at a higher level, in which a supply of cool but fluid and
suitable grease is kept, and by adjusting the top, or preferentially by means of a
float in the extension E¹, the amount of this cool grease flowing into the bath or
-

page_text: vessel E can be regulated. The other pipe leads to a receiver at a lower level, and
it serves for the outflow of hot grease, and of grease which by use has become
thick and which requires to be allowed to settle and deposit impurities before it
will be again suitable. By means of the tap the ontflow can be adjusted, and so
a perfect control is obtained, both of the temperature and quality of the grease in
the bath or vessel E.
The supply of grease may be poured into the bath or vessel by hand from time
to time, although much less conveniently than by the arrangement which I have
described, but removal of the grease by baling out would not give any satisfactory
result, as the overheated and impure grease near the bottom could not be thus
removed conveniently.
Figure 5 is a longitudinal section of an apparatus which differs in some details
from that shown in Figure 1. This apparatus is intended especially for the manu-
facture of terne plate, but it may be used also for the manufacture of tin plates,
although I do not recommend it for that purpose. It is provided with a flux box
on the entrance side, which is of a funnel-like form, and it dips at its lower end'
into the metal in the pot to a depth sufficient to maintain the column of flux. On
the exit side the bath or vessel E has formed together with it troughs I containing
clean coated metal for the supply of the upperinost rollers. The bath or vessel E
has extensions E¹, as already described, but they are shallower than the extension
in Figure 1, as in this case the finishing grease stands considerably below the level
of the uppermost rollers, and there is an air space between the surface of the grease
and the nip of these rollers.
Where the bath or vessel containing the grease on the exit side is deep, as it is
in the apparatus which I prefer for tin plate, I sometimes, in order to have more
complete control over the working, provide air flues in connection with it, as is
shewn in Figure 6. In this Figure K, K, are flues running along the sides of the
bath or vessel E, and there are suitable connections provided with dampers, by
which either cold air to carry away heat can be admitted through these flues to the
chimney, or by which, when commencing to work when the apparatus is cold, hot
air from the fire may be conducted.
In some cases I find it advisable to fix face plates in the bath or vessel E, and the
plates under treatment have to pass between them as they rise to the uppermost
rollers. L, L, in Figure 6, represent the face plates, made of steel. or wrought iron.
They are themselves carefully coated before they are put to work, and they are
supplied with clean coating metal, either by causing the troughs I which supply
the rollers above to overflow, or, as is to be preferred, a separate supply from the
store vessel is conducted to them by channels provided for the purpose. The face
plates are set at a distance apart, such that the plates can pass quite freely between
them, but nevertheless, being stationary they retain to some extent the supply of
coating metal between them, and this metal washes the surface of the plate, and
tends to prevent impurities reaching the surfaces of the uppermost rollers."
Where face plates are not employed it is sometimes advisable to give a separate
supply of coating metal to a pair of the rollers G below the uppermost pair, and for
this purpose troughs I may advantageously be applied to such rollers. Thus I am
enabled to ensure that the plates shall be well washed with clean metal before they
reach the uppermost rollers, without giving too liberal a supply of metal to the
uppermost rollers themselves, which might cause the plates to be coated more
thickly than was required.
Although I consider the most advantageous way of working is with a divided
pot kept at different temperatures at its different parts, as already described, never-
theless I can employ two separate pots of coating metal, the one hot and the other
cool. This I do by providing rollers immersed in clean molten metal or in liquid
flux, such as grease, to convey the plates from one pot to another; the arrangement
is shown in Figure 7. L, L, are a pair of conveying rollers, one larger than the
other, in order that the plate may take a curved course in leaving them; these
:

page_text: rollers raise the plate out of the hotter pot. They are driven at the same surface
speed, and are provided with troughs kept supplied with clean coating metal
separate from that in the coating pot. Any impurities which the plates may bring
over with them will be removed from the rollers by the metal in which they are
bathed, or mix with the flux on the back of these trough rollers, and can be
skimmed off by the workman from time to time from the surface of the metal in
the troughs at the back of the rollers. Curved guides ensure the entrance of the
plates, leaving the rollers L between the rollers M, M, and these revolve in grease or
flux supported upon the surface of the metal in the cooler pot, the rollers themselves
being above the level of the metal. In consequence of the lower temperature
maintained in this pot, grease or flux can be maintained in good order upon its
surface. Other rollers carry the plate forward, as already described.
In the arrangement of apparatus and the method of working, herein-before
described, there are several different points of Invention involved and some of these
I claim under another Patent granted to me and bearing even date with the Patent
of which this is the Specification. In this Specification, and under the Patent to
which it applies, I claim, in coating metals, and especially in the manufacture of tin
and terne plates, and where the plates or articles in process of coating are passed
into melted coating metal and are withdrawn by rollers through grease which is
supported on the surface of the melted coating metal,-
First. A barrier or barriers in the metal pot, which whilst permitting the plates
or articles to pass without emerging impedes the passage of heat and divides the
pot into parts, in one of which the coating metal is maintained at a high tempe-
rature suitable for coating, whilst in another or on the exit side where the finishing
grease stands upon the surface of the metal the metal is kept comparatively cool at
the lower temperature suitable for finishing.
Second. A pot containing the melted coating metal, divided by a barrier and
heated on one side of the barrier, whilst it is cooled by a current of air or other
fluid on the other side of the barrier.
Third. An extension of the bath or vessel containing the finishing grease on the
exit side beyond where the plate rises up from the metal through the grease, resting
upon the melted coating metal, in which extension, the grease being undisturbed,
deposits impurities, and which extension is also provided near the bottom with an
outlet pipe or passage with means of regulation, and also an inlet pipe with means
and appliances for obtaining a fresh supply of cool and suitable grease.
Fourth. An aperture, which by a slide or moveable piece can be opened and closed
at pleasure, and so placed as to admit of the drawing off of grease settlings or
impurities floating or resting on the metal which is beneath the grease on the exit
side of the pot containing coating metal.
Fifth. A slide or slides, forming moveable partition or partitions, separating the
extension or extensions E' from the bath or vessel E.
Sixth. The application of air flues or other equivalent cooling appliances in con-
nection with the bath or vessel containing the grease, supported on the melted
coating metal on the exit side of the pot.
Seventh. Rollers revolving in contact with clean coating metal or clean liquid
flux-conveying plates or articles in process of coating from a pot containing melted
coating metal at the high temperature suitable for coating to another pot con-
taining melted coating metal at the lower temperature suitable for finishing.
Eightb. The combined apparatus, consisting of a pot divided by a heat barrier,
of a bath or vessel containing grease resting on the cooler metal on the exit side of
such pot, of rollers immersed in the grease, and of appliances feeding such rollers
with clean coating metal, substantially as described.
Ninth. The combined apparatus, consisting of two separate pots with rollers
revolving in contact with clean coating metal or clean liquid flux, conveying the
plates from one pot to the other of a bath or vessel containing grease resting on the
:

page_text: cooler metal on the exit side, of rollers immersed in the grease, and of appliances
feeding such rollers with clean coating metal, substantially as described.
In witness whereof, I, the said Edmund Morewood, have hereunto set my
hand and seal, this Twenty-seventh day of July, in the year of our
Lord One thousand eight hundred and seventy-eight.
EDMUND MOREWOOD. (L.S.)