Improvements relating to the Coating of Plates and other Metal Articles to Protect the same from Corrosion, and Apparatus therefor.
Year: 1893

page_text: Date of Application, 20th Nov., 1893
Complete Specification Left, 13th Aug., 1894-1ccepted, 15th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements relating to the Coating of Plates and other Metal
Articles to Protect the same from Corrosion, and Apparatus
therefor.
We, SHERARD OSBORN COWPER-COLES, of 16, Adam Street, Manchester
Square, in the County of Middlesex, Engineer, and Sir BALDWIN WAKE
WALKER Captain R.N., 28 Bramham Gardens, in the County of Middlesex, do
hereby declare the nature of this invention to be as follows:-
This invention relates to the conting of plates, and other metal articles by
electro-deposition to protect the same from corrosion, and to apparatus therefor.
An important feature of the said invention consists in the application to iron or
steel plates and other metal articles of a very thin coating of zinc sufficiently
thick to protect said articles until the same can be painted, as for example in the
case of ships' plates the said thin coating will serve to protect them from corrosion
during the time the ship is being built, and before and after the plates are painted.
By this means the plates are kept in a perfect condition for receiving the paint,
and moreover a good surface or foundation is formed for the paint. Plates so
treated can be subsequently painted at less cost than can unprotected plates by
reason of the better surface provided to receive the paint, and moreover the paint
does not tend to scale off in the course of time as is the case with ordinary painted
plates; especially is this the case with steel plates.
We apply the aforesaid thin coat of zinc, to the articles which are to be
protected by electro-deposition, which admits of depositing an evenly distributed
coat of the requisite degree of thinness.
After the plates or other articles have been coated as above described we prefer
to further coat them with oil or suitable oil compound, linseed oil being used by
preference, in order to dispense with one at least of the coats of paint that are
usually applied, and so save a good part of the cost of painting. We effect this
by dipping the articles in an oil compound bath, for example a bath containing
linseed oil and oxide of iron, and while so dipped we pass a current of electricity
through the plates and oil compound.
Betore coating the plates or other articles with zinc we pass them successively
through a pickling solution, and a washing tank, the first named and the zincing
bath being kept hot by suitable steam heating coils, with arrangements to promote
circulation of the liquid if desired. The coils in the zincing bath are preferably
furnished with insulating medium between the flanges and around the bolts and
Such
under the bolt heads and rivets to avoid short circuiting the current.
insulation is preferably effected by rubber rings between the flanges, and by
vulcanised fibre washers around the bolts. The pickling, washing and zincing
tanks are preferably made of wood suitably lined with Stockholm tar put on hot
and then finished with pitch, dusted with fine sand. The pickling tank is further
lined with chemical sheet lead.
We preferably provide a suitable arrangement of connecting and disconnecting
or contact making and breaking plugs whereby the pickling and zincing tanks can
be joined up in series or in parallel as regards the electric current, or can be
disconnected and either worked independently of the other, or either tank can be
worked as a shunt. These tanks together with the washing tanks are preferably
so grouped that a radial crane provided with a trolley worked by an electric or
other motor can be very conveniently used for lifting the work from one tank and
passing it on to the next.

page_text: The conductor for conveying the current to the tanks is built up of strips of
copper separated by spacing pieces to allow of free circulation of air between the
strips. Suitable clamps are provided at intervals to brace said strips together.
Where bends and junctions are required we provide suitable metal boxes into which
the ends of the conductor are keyed or otherwise secured, solder being preferably
run into the boxes so as to ensure and maintain a perfect electrical connection.
We sometimes for special work provide for dividing the zincing tank into two or
more sections and working said sections in series.
The construction of the anodes and their connections forms an important detail
of our invention. According to one construction we furnish the several anodes of
each tank with a common copper conducting bar and secure the same by means of
clips and pinching screws to an iron girder of I-section resting on the tank.
Distance pieces are provided between the web of the girder and the said copper
bar. In another construction two supporting bars are provided separated by
distance pieces and between which the anodes and copper conductor are secured by
pinching screws.
For many classes of goods it is desirable that the anodes should be rotatable so that
they may be set parallel with the several faces of irregular shaped articles. For
this purpose each anode is suspended by a central spindle from a suitable cross
girder which is preferably constructed of two beams bolted together, the anode
spindle passing between them and being suspended by a cottar or a cap or other
suitable device. Each beam is preferably constructed of a central copper strip
and an iron bar on each side of said strip all securely bolted or riveted together.
The two beams are separated by suitable distance pieces. The girder so formed
rests and can slide on the main copper conductor which is preferably made up of a
number of thin plates bolted together. The conductor is bolted to the positive
lead which is fixed to the tank. The cathode rod in like manner rests upon a
similar conductor bolted to the negative lead. The cathode rod is built up of a
central iron bar and side copper bars riveted thereto. Both the anode and the
cathode girders are furnished at their ends with solid castings to which are secured
contact pads constructed of wire gauze somewhat similar to those used for dynamo
brushes. Or in lieu of wire gauze pads or shoes we sometimes use a number of
thin copper strips preferably spaced a suitable distance apart, and set at an angle
and securely held together by a pinching screw. The girders are provided with
eye-bolts to facilitate the lifting of the same. The main conductor at the end of
the zincing tank is in some instances supported by rollers resting on adjustable
roller paths whereby said conductor can be readily given a horizontal and vertical
movement when desired. Said roller paths may be conveniently formed by pivoted
arms supported at their free ends on adjusting screws.
Another form of adjustable or flexible anodes constructed in accordance with
this invention is as follows, that is to say, the anode consists of a number of strips
or laths each of which is pivoted or connected by a socket joint to a clamping
piece which is clamped to the conductors. Said conductors are preferably double
and made up of a large number of very thin wires; they are thus very flexible and
can be bent to any desired shape. Moreover since each anode strip can be turned
through any angle independently of the other strips it will be apparent that the
anodes can be adjusted or adapted very easily to conform to the configuration of
any irregular article that is being coated. Each anode strip is loaded at its lower
end by a large lead weight to which it is secured preferably by hard wood pins,
and from which it is preferably insulated.
Each said weight rests on the bottom of the zincing tank and is rounded or of
hemispherical shape on its lower face so that it tends always to turn to that position
in which the anode is vertical, and will so turn when the upper end of the anode is
free to move.
For holding some classes of small work while in the zincing tank we provide
suitable suspending clips adapted to hang from the cathode bars. Said clips are
furnished with spring copper clasps to ensure good contact with said bars, and

page_text: They are furnished
Said jaws may be
with hooks or cross bars to facilitate the lifting of the same.
with hinged jaws at their lower ends to hold the work.
controlled by a spring or by thumb screws and by elastic bands which latter serve
to open the jaws when the thumb screws are slacked back.
Dated this 20th day of November 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.
COMI LEID DE MULTICATION.
Improvements relating to the Coating of Plates and other Metal
Articles to Protect the same from Corrosion, and Apparatus
therefor.
We, SHERARD OSBORN COWPER-COLES, of 16 Adam Street, Manchester
Square, in the County of London, Engineer, and Sir BALDWIN WAKE WALKER
Bart. Captain R.N. 28 Bramham Gardens, in the County of London, 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 :-
This invention relates to the coating of plates, and other metal articles, by
electro-deposition, to protect the said plates, or other metal articles, from corrosion,
and to apparatus for use in effecting the said coating.
An important feature of the said invention consists in the application, by
electro-deposition, to iron, or steel, plates, and other metal articles, of a very thin,
and evenly distributed, coating of zinc or zinc compound sufficient to protect the
said plates, or articles, until they can be painted. For example, in the case of
ships' plates, the said thin coating will serve to protect them from corrosion during
the time the ship is being built, and before, and after, the plates are painted. By
this means the plates are kept in a perfect condition for receiving the paint, and
moreover a good surface, or foundation is formed for the paint. Plates or other
articles so treated can he subsequently painted at less cost than can unprotected
plates or articles by reason of the better surface provided to receive the paint, and
moreover the paint does not tend to scale off in the course of time, as is the case
with ordinary painted plates or articles, and especially is this the case with steel
plates or articles.
After the plates, or other articles, have been coated as above described we prefer
to coat them with oil, or suitable oil compound, linseed oil being used by preference,
in order to dispense with one, at least, of the coats of paint that are usually applied,
and so save a good part of the cost of painting. We can conveniently effect this
coating with oil, or oil compound, by dipping the plates, or articles, in a bath of
oil, or of oil compound; for example, in a bath containing linseed oil, and oxide of
iron, and while so dipped we pass a current of electricity through the plates or
articles and oil compound.
In the following descripton of our invention we will refer to the accompanying
drawings,
Fig. 1 of which represents, in plan, apparatus suitable for use in carrying out our
invention, and Fig. 2 represents the said apparatus partly in elevation and partly
in vertical section.
Figures 3, 4, 5 and 6 represent contact making, and breaking, plugs and contact
pieces, whereby the pickling, and zincing, tanks can be electrically connected in
series, or in parallel.
Figures 7 to 11 inclusive illustrate means whereby the zincing tank can be
divided into two, or more, sections, or cells, and be worked in series, or in parallel,
as desired.
Fig. 12 shews in transverse section one form of connection for the anodes, and.

page_text: Figures 13 and 14 represent in transverse section, and plan, respectively, another
form of connection for the anodes.
Fig. 15 represents at right angles to each other two views of an adjustable, or
rotatable, support for the anodes, and Fig. 16 shows similar views of another form
of adjustable support for the anodes.
Figures 17, 18 and 19 represent, diagrammatically, adjustable anodes arranged
to suit articles of various shapes.
Figures 20, 21 and 22 represent respectively in side elevation, in plan, and in
transverse section, a cathode rod built up of a central iron bar, and side copper
bars.
Figures 23 and 24 are elevations at right angles to each other of a suspending
clip for hanging articles onto the cathode bars and Fig. 25 is a modification of the
upper part of the said clip.
Fig. 26 is a side elevation shewing an arrangement for operating the cathode
bars, for agitating the electrolyte, and Fig. 27 is a section at right angles to
Fig. 26 shewing one of clips in position on the cathode bar.
Before coating plates, or other articles, with zinc, or zinc compound, we pass
them successively through a pickling solution in a tank A Figures 1 and 2, a
washing tank B, and a zincing tank C, the pickling, and zincing, baths being kept
hot, which may be effected by means of steam heating coils, with arrangements to
promote circulation of the liquids if desired. If the plates, or articles, to be coated
with zinc, or zinc compound, be covered with grease, we first pass them through an
alkaline bath in a vessel A', Fig. 1, kept at a temperature of preferably about
200 degrees Fahrenheit by means of a steam coil a¹. The coils in the zincing
bath Care preferably furnished with insulating medium between the flanges and
around the bolts and under the bolt heads and rivets to avoid short circuiting the
current. Such insulation is preferably effected by rubber rings between the flanges,
and by vulcanised fibre washers around the bolts. The pickling, washing and
zincing tanks A B and C are preferably made of wood suitably lined with
Stockholm tar, put on hot, and then finished with pitch and dusted with fine sand.
The pickling tank should be further lined with chemical sheet lead.
We preferably provide a suitable arrangement of plates or blocks a* b* c* d* and
connecting and disconnecting or contact making and breaking plugs as illustrated
in Figures 3, 4, 5 and 6 whereby the pickling tank A, and the zincing tank C, can
be electrically connected, or joined up, in series, as shewn in Figure 5, or in parallel
as shewn in Figure 6, or can be disconnected and either be worked independently
of the other. Figure 3 shews the plug in position when the zincing tank C, only,
is in circuit and Figure 4 the position when the pickling tank only is in circuit.
In Figure 3 we have indicated the zincing tank at C and the pickling tank at A
and the dynamo at X and the electric connections, but we have not considered it
necessary to repeat the illustration of these in Figs. 4, 5 and 6. Either tank can
be worked as a shunt. The several tanks are preferably grouped as shewn in
Figures 1 and 2 so that a radial crane D, provided with a trolley E worked by an
electric, or other motor, (or by a hand winch F as shewn), can be very conveniently
used for lifting the work from either tank and passing it on to the next.
The conductor for conveying the current to the tanks may be built up of strips of
copper separated by spacing pieces to allow of free circulation of air between the
strips. Suitable clamps are provided at intervals to brace the said strips together.
Where bends and junctions are required we may provide metal boxes into which
the ends of the conductor are keyed or otherwise secured, solder being preferably
run into the boxes so as to ensure and maintain a perfect electrical connection.
We sometimes for special work, such, for instance, as roofing sheets, provide for
dividing the zincing tank into two, or more, sections as shewn in Figures 7 to 11
and working the said sections in series, or in parallel, as desired.
Figure 7 shews in plan a portion of a tank so constructed and Figure 8 is a
section thereof. The tank C is divided by vertical partitions 1, of wood or other
suitable non-conducting material, into a number of compartments, or cells, 2.

page_text: Each partition is covered on its opposite sides with conducting material, 3, 3×,
constituting anodes (we will call these anode plates), a strip of wood, or other
suitable non-conducting material, being laid on top of each partition to prevent
short circuiting. On each of two opposite sides, or ends, of the tank C, are two
sets, or series, of conducting bars 5 and 6, the several bars of each set, or series,
being arranged out of contact one with the other. Each anode plate 3 is provided
at its opposite ends with a brush contact 7 making contact with the conducting
bars 5, the anode plates 3* carrying at each end a similar contact brush 8, making
contact with the bars 5, and also an additional brush contact 9 (a sectional detail
of which is shewn in Fig. 11) for making, and breaking, contact as desired with the
conducting bars 6. Over each cell 2, in the tank, is placed a cathode bar 10, each
of which is provided at its opposite ends, 11, with a brush contact which makes
contact with the conducting bars 6. When working the cells of the tank in series,
as shewn, for example, in Fig. 7, the current entering the conducting bars 5, passes
from the first portion thereof to the contact brush 7, to the anode plate 3, on one
side of the first partition 1, thence through the electrolyte and the article contained
in the first cell of the tank to the cathode bar 10 of that cell and therefrom by the
brush at 11, to the first bar of the series of bars 6. The brush 9, carried by the
other anode plate 3* on the opposite side of the partition 1, being in contact with
the said first bar of the series 6, the current is conducted partly through the said
anode plate 3* to the electrolyte in the second cell of the tank and partly by the
brush 8 to the next bar of the series of bars 5 and thence by the brush 7 and anode
plate 3 on the second partition 1 into the electrolyte contained in the said second
cell of the tank. The current then passes to the cathode bar 10 of the second cell
and through the brush contacts 11, 9, 7 and 8 conducting bars 5 and 6, and anode
plates 3, 3× on the next partition 1 to the third cell of the tank and so on through
all or any desired number of the cells.
If it be desired to work the cells of the tank in parallel the several bars of the
series of bars 6 are connected together by links 12 as shewn in Fig. 10 and the
brushes 9 are raised out of contact with the said bars and the anode plates 3 and 3*
on each partition 1 are connected together by metallic clips 13 as shewn in Fig. 9
or by screws, bayonet joints or other fastenings. The several anode plates 3, 3×
being thus joined together the current entering the conducting bars 5 passes
through the brushes 7 and 8 and anode plates 3, 3* into the electrolyte contained
in the several cells and therefrom by the cathode bars 10 to the conducting bars 6
as will be clearly understood by reference to the drawings.
The arrangement and construction of the anodes and their connections forins an
important detail of this invention. According to one construction as shewn in
cross section in Figure 12 we convey the current to the several anodes (indicated
at G) of each tank by means of a copper conducting bar G secured to an iron
girder K of I section resting on the tank, distance pieces L being provided between
the web of the girder K and the said copper bar G. The anodes G are secured in
contact with the copper strip G by means of clips H and pinching screws I. In
another construction as shewn in cross section in Figure 13 and in plan in
Figure 14 two iron supporting bars K K are provided separated by distance
pieces L the copper conductor G being secured to one of the said bars and the
anodes G being held in contact therewith by means of the pinching screws I
passed through the other of the said bars.
For many classes of goods it is desirable that the anodes should be rotatable so
that they may be set parallel with the several faces of articles of irregular shape.
For this purpose each anode is suspended by a central spindle Q (as shewn in
Figure 15) from a cross girder which is preferably constructed of two beams K K'
bolted together, the anode spindle passing between them and being suspended by a
cottar, or a cap, or other suitable device, such as the nut q screwed on to the
projecting end of the spindle Q. Each beam is preferably constructed of a central
copper strip k, and an iron bar on each side of the said strip, all being securely
bolted or rivetted together. The two beams K.K' are separated by suitable

page_text: distance pieces. The girder so formed rests and can slide on the main copper
conductor which is preferably made up of a number of thin plates bolted together.
The said main conductor is bolted to the positive lead which is fixed to the tank.
The cathode rod in like manner rests upon a similar conductor bolsed to the
negative lead.
Another form of adjustable or flexible anodes constructed in accordance with
this invention is shewn in Figure 16 (which represent views at right angles to
each other) the anode consisting of a number of strips or laths forming a cage
each of which is pivotted or connected by a ball and socket joint e to a piece f
which is clamped to the conductor L³ the said conductor being preferably double
each part being made up of a large number of very thin wires; they are thus very
flexible and can be bent to any desired shape. Moreover since each anode can be
turned through any angle independently of the other or others it will be apparent
that the said anodes can be very readily adjusted or adapted to conform to the
configuration of any irregular or other article that is being coated. Examples
of such placement are shewn in Figures 17, 18 and 19 where the anodes are
marked L. Each anode L2 is loaded at its lower end by a large or heavy
weight P (say of lead) from which it is preferably insulated and to which it is
secured preferably by hard wood pins. Each weight rests on the bottom of the
zincing tank and may be rounded or of hemispherical shape on its lower face so
that it tends always to take a position in which the anode is vertical, and will
so turn when the upper end of the anode is free to move.
The cathode rod can be built up of a central iron bar and side copper bars
rivetted thereto as illustrated in side view in Figure 20 plan in Figure 21 and
transverse section in Figure 22, the central iron bar being marked L' and the side
copper bars being marked l. Both the anode and the cathode girders are
preferably furnished at their ends with solid castings a in which are secured
contact pads or shoes constructed of wire gauze somewhat similar to those used for
dynamo brushes. Or in lieu of wire gauze pads or shoes we sometimes use a
number of thin copper strips N preferably spaced at some little distance apart and
set at an angle and securely held together in a recess in the castings a by a
pinching screw c. The eye bolts d are to facilitate lifting.
For holding some classes of small work while in the zincing tank we provide
suspending clips such as we have shewn in Figures 23, 24 and 25 adapted to hang
from the cathode bars. These clips are furnished with spring copper clasps g to
ensure good contact with the said bars 7 (Figures 20, 21 and 22) and with hooks
eyes or cross bars to facilitate the lifting of the clips with the articles which
they hold. They are furnished at their lower ends with jaws O O2 to hold the
articles, the jaw O being hinged at O' to the jaw O' and the said jaws may be
forced together by a spring, or by a thumb screw as at Os elastic bands O₁ serving
to open the jaws when the screws O³ are slacked back.
The main conductor at the end of the zincing tank is in some instances supported
by rollers k as shewn in Figures 26 and 27 resting on roller paths 14 whereby a
horizontal and vertical movement can be readily imparted to the said conductor
when desired. The said roller paths may be conveniently formed as shewn by
pivotted arms supported at their free ends on adjusting screws 15 by which the
angles of the said arms can be altered so as to regulate the amount of rise and fall
of the suspension bars L' during their traverse. The bar L is shewn as a girder
of sufficient width to accommodate the rollers k. The rollers and inclined surfaces
may be arranged at right angles to the position shewn so that they are operated
sideways instead of lengthwise to give the desired movement thereto.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1. The protection of iron or steel plates or articles by first applying a thin
coating of zinc or zinc. compound thereto, and then applying oil or an oily

page_text: compound or mixture over the zinc or zinc compound and finally a coat or coats of
paint over all as hereinbefore set forth.
2. Apparatus for the electro deposition of coatings on plates or other articles
consisting of the combination of tanks as hereinbefore described and shewn in
Figures 1 and 2 in combination with means for passing electric current there-
through as required as hereinbefore described with regard to Figures 3 to 6 of the
accompanying drawings.
3. In electro-depositing apparatus for coating plates or other articles providing
the anodes with a copper conducting bar common to all the anodes of the electro
depositing tank and securing the said bar. by clips and pinching screws to a girder
with distance pieces between substantially as hereinbefore described and shown in
Figure 12 of the accompanying drawings.
4. In electro depositing apparatus for coating plates or other articles providing
the anodes with two supporting bars separated by distance pieces between which
the anodes and copper conductor are secured by pinching screws, substantially
as hereinbefore described and shewn in Figures 13 and 14 of the accompanying
drawings.
5. In electro depositing apparatus for coating plates or other articles the means
substantially as hereinbefore described for mounting the anodes so that they can be
rotated or partly rotated for adjusting them to irregularly shaped articles
substantially as hereinbefore described and also the particular arrangements for
this purpose shewn in and described with reference to Figures 15 and 16 of the
accompanying drawings.
6. In electro depositing apparatus for coating plates or other articles providing
the girders or supporting bars of the elements with castings with contact pads or
shoes of wire gauze or thin copper strips substantially as hereinbefore described
and illustrated in Figures 20, 21 and 22 of the accompanying drawings.
7. In electro depositing apparatus for coating plates or other articles providing
the anodes with a heavy weight at bottom to rest on the bottom of the tank
substantially as and for the purpose hereinbefore described.
8. In electro depositing apparatus for coating plates or other articles the
construction of suspending clips for the articles to be treated substantially as
hereinbefore described and illustrated by Figures 23, 24 and 25 of the
accompanying drawings.
Dated this 13th day of August 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.