AN IMPROVED MODE OF AND APPLIANCES FOR PREVENTING THE CORROSION OF IRON PIPES
Year: 1872

page_text: LETTERS PATENT to George Hand Smith, of the City and State of
New York, United States of America, now of No. 8, Southampton
Buildings, London, Gentleman, for the Invention of "AN IMPROVED
MODE OF AND APPLIANCES FOR PREVENTING THE CORROSION OF IRON PIPES
COMPLETE SPECIFICATION filed by the said George Hand Smith at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 26th March 1872, pursuant to the 9th Section -
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HAND SMITH, of the City and State of New York, United States of
America, now of No. 8, Southampton Buildings, London, Gentleman,
send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED
MODE OF AND APPLIANCES FOR PREVENTING THE CORROSION OF IRON PIPES OR
TUBES, AND KEEPING THEM FREE FROM INCRUSTATION," and have petitioned
Her Majesty to grant unto me, my executors, administrators, and
assigns, Her Royal Letters Patent for the same, and have made solemn
Declaration that I am the true and first Inventor thereof.*

page_text: NOW KNOW YE, that I, the said George Hand Smith, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention and
in what manner the same is to be performed, in and by the following
statement:-
My said Invention relates to the protection of. iron pipes or tubes
from the destructive effects of corrosion or oxidation, and to keeping
them free from incrustation or the deposit of scales on their surfaces.
The said Invention is applicable to tubes of all sizes and either of
wrought or cast iron. It is chiefly intended for the preservation of
pipes or tubes used for the conveyance of sea or fresh water, sewage, and
other similar liquid matters, and of tubes which form part of the
structure of steam boilers or other vessels or apparatus wherein the said
tubes are immersed in or contain water, or are exposed to the steam or
vapour of the same. Also iron pipes or tubes exposed to moisture in
the atmosphere and otherwise, and iron columns and pillars, iron
caissons for bridges, iron piles, and other tubular or hollow objects
constructed of wrought or cast iron exposed to water, steam, moisture,
or atmospheric influences. But I wish it understood that this Invention
is not designed to prevent the corrosive effect of strong acids or salts
or other substances made or compounded in chemical laboratories or
manufactories, which substances do not exist naturally and are not
ordinarily brought into contact with iron pipes or tubes and similar
objects used for the purposes above specified and similar purposes.
The said Invention is based upon the application to the iron tubes to
be protected of a material electro-positive to the iron, and which is
therefore attacked instead of the iron by the destructive agency that
would otherwise corrode or oxidise the latter. And the object of the
said Invention is the application of the protective material to the tubes
or pipes in a convenient, economical, and efficient manner.
For this purpose I proceed as follows:-I first make an alloy of zinc
and tin, preferably in the proportions stated in the Provisional Specifica-
tion accompanying my application for Letters Patent, dated the Twenty-
eighth day of February, in the year of our Lord One thousand eight
hundred and seventy-two, No. 624. Or I may use an alloy of other
metals, which when combined will have the same effect as the said alloy
of zinc or tin, as set forth in the said former Specification. Or I may
use any metal or alloy which will be electro-positive to the iron, although

page_text: the best results will only be obtained with the alloy described in the said
Specification, or one bearing the same voltaic relation to the iron for
the purposes therein stated.
For wrought-iron pipes or tubes and for cast-iron tubes not more than
about two or two and a half inches in diameter, the protection is best
obtained by the use of couplings or connections made entirely or
partially of the aforesaid alloy, and applied in the place of the ordinary
hoops, "elbows," "bends," "T pieces," and other connections used for
uniting the lengths or sections of such pipes, or for attaching them to
any vessels or apparatus with which they are connected. For small
wrought-iron pipes or tubes I prefer to make the coupling entirely of
the protective alloy, but for the larger sizes of these pipes it may be
more economical to make the coupling of some cheaper metal and coat
or cover it wholly or partially with the said alloy. These couplings have
screw threads formed in them for the reception of the screwed ends of
the pipes, and are fixed on the said pipes or removed therefrom by the
ordinary appliances. Care must be taken that a space is left in the
couplings between the two ends of the pipes or tubes secured therein,
otherwise there will be no voltaic or galvanic action upon the alloy, and
the object of the Invention will not be accomplished.
In cases where such couplings or connections are not required or
could not be conveniently applied to the pipes, I place in the ends of the
latter rings or hoops made of the protective alloy.
For large cast-iron tubes, such as are used in towns and cities for the
conveyance of water, gas, or sewage, I form in the said tubes annular
grooves or channels for the reception of rings, hoops, or segments made
of the protective alloy or metal. But when my Invention is to be
applied to pipes or tubes already in use I fix the said rings, hoops, or
segments of the protective alloy upon the inner surface of the pipes,
taking care that they shall offer as little obstruction as possible to the
passage of the liquids through the pipes. And when such pipes have
their separate lengths or sections connected by socket joints, as is' com-
monly the case, I make the protective rings or hoops of the same
diameter internally and externally as the small ends of the pipes, and
place the said rings at the bottom of the socket between the same and
the end of the pipe inserted therein.
When the tubes or pipes to be protected form part of a steam boiler

page_text: exposed to the corrosive or destructive influence, I place rings or hoops
made of the said alloy upon the said tubes at the ends of the pipes, or
at such distances apart thereon as will be found most convenient and
efficient. For small tubes, such as are used in locomotive boilers, the
said hoops or rings may be made in one piece and driven on the ends of
the tubes, but for the large flue tubes of Cornish and other similar
boilers it may be more convenient to make the said rings in two or more
pieces, and secure them together or to the tube by screws, or rivets, or by
soldering them. And I may further protect the tubes and other parts
of a boiler by placing rings or hoops made of the said alloy around
the interior surface of the barrel or shell of the said boiler.
In applying the aforesaid couplings or rings according to my Inven-
tion, as above described, it is essential in every case that the protective
metal or alloy shall be fully exposed to the corrosive action from which
it is desired to protect the iron, otherwise the desired result will not be
obtained.
Having thus fully described my said Invention and the manner of
performing the same, I wish it understood that I claim,-
First. Connecting or uniting iron pipes or tubes with couplings or
_connections made of or coated with an alloy or metal which is electro-
positive to the iron, as herein set forth for the purposes specified.
Second. Providing iron tubes, columns, or other like objects with
hoops or segments formed of an alloy or metal electro-positive to the
iron, as herein set forth for the purposes specified.
In witness whereof, I, the said George Hand Smith, have hereunto
set my hand and seal, this Twenty-fifth day of March, in
the year of our Lord One thousand eight hundred and seventy-
GEORGE HAND SMITH. (L.S.)
Witness,
W. ROBT. LAKE,
8, Southampton Buildings,
London.