IMPROVEMENTS IN PROTECTING THE IRON OR STEEL MATERIAL OF STEAM BOILERS FROM THE CORROSIVE ACTION OF SALT, OR ACID, OR OTHER AGENT IN THE WATER."
Year: 1878

page_text: LETTERS PATENT to John Harrop, of Sheffield, in the County of York, and
James Howden, of Glasgow, in the County of Lanark, for the Invention of
"IMPROVEMENTS IN PROTECTING THE IRON OR STEEL MATERIAL OF STEAM
BOILERS FROM THE CORROSIVE ACTION OF SALT, OR ACID, OR OTHER AGENT IN
THE WATER."
PROVISIONAL SPECIFICATION left by the said John Harrop and James
Howden at the Office of the Commissioners of Patents on the 14th March
1878.
JOHN HARROP, of Sheffield, in the County of York, and JAMES HOWDEN, of
Glasgow, in the County of Lanark, "IMPROVEMENTS IN PROTECTING THE IRON OR
STEEL MATERIAL OF STEAM BOILERS FROM THE CORROSIVE ACTION OF SALT, OR
ACID, OR OTHER AGENT IN THE WATER."
This Invention consists in applying zinc in an improved manner, herein-after
described, so as in an efficient and economical manner to electrically protect the
iron or steel material of steam boilers from the corrosive action of salt, or acid, or
other agent in the water.
In carrying out the Invention the zinc is immersed in the water of the boiler in
any convenient position or positions, and to insure that the intended electrical pro-
tective action shall be exerted with as little expenditure as possible of the zinc; it is
put in continuous metallic conductive connection with the plates or other parts of
the boiler that are liable to corrosion in one or other of the modes herein-after
described, whilst means are also employed to properly connect the plates and other
parts of the boiler amongst themselves in order that the action may be adequately
distributed throughout, and the application of numerous pieces of zinc be rendered
unnecessary.
The zinc is by preference used in the form of a sheet or sheets or other piece or
pieces presenting considerable surface, and is placed vertically, so that deposits may
be less liable to rest on it and mask its action.

page_text: The zinc is connected to the iron or steel of the boiler by one or more copper
wires, and each copper wire is united to the zinc in a manner securing a large and
perfect contact surface between the two.
When uniting the copper and zinc care is taken that the contact surfaces are as
clean as possible, and that a perfect metallic junction is made.
One mode of making a suitable union is to cast a block of zinc upon a part of
the copper wire, and subsequently roll the block down to a suitable thickness.
A second mode consists in giving a zig-zag or serpentine form to the end of the
wire, and soldering it down upon the zinc.
A third mode consists in lacing the copper wire through holes made through the
zinc, with or without the addition of solder.
A fourth mode consists in making holes through or partly through the zinc, and
indenting the copper wire into such holes, solder being added if necessary.
A fifth mode consists in soldering or otherwise fixing two or more short wires to
the zinc, and uniting the ends of these to a single wire.
The copper wire may be round or ribbon-shaped, or of other suitable form.
The end of each copper wire from the zinc is put in perfect metallic connection
with the iron or steel to be protected by firmly inserting the wire into a hole bored.
into the plate or picce, the end of the copper wire as well as the interior of the hole
being carefully made clean and bright, and a proper fit, so that the hole may be
completely filled by the wire, and water effectually excluded.
The hole and wire may be smooth, or they may be screwed.
The wire between the iron or steel and tho zinc may be made so as to be easily
separated at any point, being connected by screw couplings or otherwise, so that
the part attached to the zinc can be detached for the purpose of renewing the
zinc.
To insure a proper distribution of the electric protective action, care is taken to
have the several plates and other iron or steel parts requiring protection in perfect
metallic conductive connection with each other. For this purpose small holes are
bored through the plates where they overlap or are in contact, and these holes being
kept clean and bright, clean bright bits of copper or iron are rivetted or otherwise
tightly fixed in them in a manner to exclude water. Each plate is to be connected
in this way at one or more points with every plate in contact with it, and which
zequires protection.
If the boiler has tubes the conductive connection of each tube with the tube
plates is insured by boring a small hole at one end or at each end through the tube,
and some distance into the tube plate, and driving or screwing a copper pin into
each such hole, care being taken that the contact surfaces are clean and bright, and
that the pin is fixed with sufficient tightness to prevent the entrance of anything
that might impair the metallic contact.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Harrop and James Howden in the Great Seal Patent Office
on the 13th September 1878.
JOHN HARROP, of Sheffield, in the County of York, and JAMES HOWDEN, of
Glasgow, in the County of Lanark. "IMPROVEMENTS IN PROTECTING THE IRON OR
STEEL MATERIAL OF STEAM BOILERS FROM THE CORROSIVE ACTION OF SALT, OR
ACID, OR OTHER AGENT IN THE WATER."
Our said Invention consists in applying zinc in an improved manner, herein-after
described, so as in an efficient and economical manner to electrically protect the
iron or steel material of steam boilers from the corrosive action of salt, or acid, or
other agent in the water.
In carrying out our Invention the zinc is immersed in the water of the boiler in
any convenient position or positions, and to insure that the intended electric pro-
tective action shall be exerted with as little expenditure as possible of the zinc'; it is
put in continuous metallic conductive connection with the plates or other parts of
the boiler that are liable to corrosion in one or other of the modes herein-after
described, whilst means are also employed to properly connect the plates and other
parts of the boiler amongst themselves in order that the action may be adequately
distributed throughout, and the application of numerous pieces of zinc be rendered
unnecessary.
The zinc is by preference used in the form of a slicet or sheets or other piece or
pieces presenting considerable surface, and is placed vertically, so that deposits may
be less liable to rest on it and mask its action.
The zinc is connected to the iron or steel of the boiler by one or more copper
wires or rods, and each copper wire or rod is united to the zinc in a manner securing
a large and perfect contact surface between the two.
When uniting the copper and zinc care is taken that the contact surfaces are as
clean as possible, and that a perfect metallic junction is inade.
And in order that our said Invention and the manner of performing the same may
be properly understood, we hereunto append a Sheet of explanatory Drawings, to
be herein-after referred to, and representing examples of the modes in which we
combine the zinc and copper; also of the modes in which we arrange and connect
the zinc picces in a boiler; and also of the modes in which we insure continuous
metallic conductive connection between different parts of the boiler. In the
Drawings the same reference letters and numerals are used to mark the same or like
parts wherever they are repeated.
One of our modes of making a suitable union between the zinc and the copper
is to cast a block of zinc Z upon a copper wire or rod C, and to roll the block down
to a suitable thickness; or the zinc may be at once cast in the intended final form,
and the rolling be dispensed with. A compound plate made in either of these ways
is represented in face and edge views in Figures 1 and 2, the copper C within the
zinc Z being indicated by dotted lines, and being in a serpentine form.
A second mode, shown in Figures 3 and 4, consists in giving a zig-zag or ser-
pentine form to the end of the copper wire or rod C, and soldering it down upon
the zinc plate Z.
A third mode, shown in Figures 5 and 6, consists in lacing the copper wire C
through holes made through the zinc plate Z, with or without the addition of
solder.
A fourth mode, shown in edge view in Figure 7, consists in making holes through
or partly through the zinc plate Z, and indenting the copper wire or rod C into such
holes, solder being added if necessary.
A fifth mode, shown in face view in Figure 8 and in edge view in Figure 9, con-
sists in binding the zinc plate Z between two copper straps C, which latter are
connected by screw bolts or rivets of copper passing through the zinc plate Z.

page_text: A sixth mode consists in soldering or otherwise fixing two or more copper wires
or rods C to the zinc plate Z, and uniting the ends of these to a single copper wire
or rod. A modification of this mode is shown in face and edge views in Figures 10
and 11, in which modification the two copper wires or rods Caro passed through
holes bored or otherwise formed edgeways through the zinc plate Z, and fixed by
screw nuts 21.
Figures 12 and 13 show a modification in which a single copper wire or rod C is
fixed in the zinc plate Z in the same way.
Figures 14 and 15 are a face view and a section of a modification in which the
copper C is made by casting or otherwise in the form of a star, as indicated by 1
dotted lines in Figure 14, and the zinc Z is cast on the copper in the form of a
disc.
The copper wire or rod may be round or ribbon-shaped, or of other suitable form,
in any of the modifications herein-before described or shown in the accompanying
Drawings, and also in any analogous modifications embodying the same principles 1
of construction.
Each copper wire or rod C from the zinc Z is put in perfect métallic connection
with the iron or steel S to be protected by firmly inserting the wire or rod into a
hole bored in the plate or piece, the end of the copper wire or rod as well as the
interior of the hole being carefully made clean and bright, and a proper fit, so that
the hole may be completely filled by the wire or rod, and water effectually
excluded.
The hole and wire or rod may be smooth, or they may be screwed.
Figures 16 and 17 are vertical sections as at right angles to each other, showing
parts of a marine boiler provided with zinc plates Z in various positions; these zinc
plates Z we prefer to place near man-hole doors, where they are conveniently
accessible for examination or renewal; and although two or three such plates Z may
be placed near together, they may be connected to different parts of the boiler by
copper wires or rods C of different lengths.
The modification of zinc plate Z, shown in Figures 14 and 15, may be con-
veniently attached to a boiler plate S by a short copper rod C screwed into the
copper core on which the zinc plate Z is cast, and also screwed into the boiler
plate S; in other cases the zinc plates Z may be held by iron studs or rods, or in
any other convenient way; but in all cases the copper embedded in or attached to
each zinc plate Z must be connected to the iron or steel of the boiler by a copper
rod or wire, with the precautions herein-before prescribed for insuring a perfect
metallic conductive connection.
The copper wire or rod C connecting each zinc plate Z with the iron or steel S of
the boiler is arranged to admit of easy separation at a convenient point, so that the
part attached to the zinc can be detached for the purpose of renewing the zinc.
For this purpose simple screw couplings 22, of the kind shown enlarged in Figures
18 and 19, and made of copper, may be employed, being applied close to the zinc
plate, as shown in Figures 1 to 13, or at any other convenient part of the copper
connection.
To insure a proper distribution of the electric protective action, care is taken to
have the several plates, and other iron or steel parts requiring protection in perfect
metallic conductive connection with each other. For this purpose small holes are
bored through the plates S where they overlap or are in contact, and these holes
being kept clean and bright, clean bright bits 23 of copper are rivetted or otherwise
tightly fixed in them in a manner to exclude water; these conductive bits or
rivets 23 are shown black in Figures 16 and 17, the ordinary rivets not being
shown. Each plate S is to be connected in this way at one or more points with
every plate in contact with it, and which requires protection.
If the boiler has tubes 24, the conductive connection of each tube with the tube
plates 25 is insured, as shown in Figure 20, by boring a small hole at one end or at
each end through the tube 24, and some distance into the tube plate 25, and driving
or screwing a copper pin 23 into.cach such hole, care being taken that -the contact'

page_text: surfaces are clean and bright, and that each pin 23 is fixed with sufficient
tightness to prevent the entrance of anything that might impair the metallic
contact.
Having thus particularly described our said Invention, and the manner of per-
forming the same, we have to state that we do not restrict ourselves to the precise
details herein described or delineated, and that wej do not claim the use of zinc
excepting when combined and applied as herein-before described, but that what we
believe to be novel and original, and claim as the Invention secured to us by and
in terms of the herein-before in part recited Letters Patent is,-
1. The application of zinc for protecting the iron or steel material of steam
boilers from the corrosive action of salt, or acid, or other agent in the water, such
zinc being combined with or attached to copper, and connected by means of copper
to the iron and steel, substantially in the improved manner herein-before described.
2. The connecting of the zinc to the iron or steel of the boiler by means of copper
fixed in perfect metallic conductive contact with both, and substantially in the
manner herein-before described.
3. The fitting of the copper conductors with couplings, substantially as and for
the purposes herein-before described.
4. The insuring of perfect metallic conducting connection between the several
plates or parts of the boiler, substantially in the manner herein-before described.
In witness whereof, I, the said James Howden, on behalf of the said John
Harrop and myself, have hereunto set my hand and seal, this Eleventh day
of September, in the year of our Lord One thousand eight hundred and
seventy-eight.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JAMES HOWDEN. (L.S.)