IMPROVEMENTS IN THE PRESERVATION OF IRON
Year: 1873

page_text: LETTERS PATENT to William Henry Sterling, of San Francisco,
State of California, in the United States of America, Chemist, for
the Invention of "IMPROVEMENTS IN THE PRESERVATION OF IRON."
COMPLETE SPECIFICATION filed by the said William Henry Sterling
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 6th June 1873, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HENRY STERLING, of San Francisco, State of California, in the United
States of America, Chemist, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN THE PRESERVATION OF IRON," 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 William Henry Sterling 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 :—
The nature of my said Invention consists in the impregnation and
saturation of the structure of the metal iron with a non-oxidizing or
non-oxidizable substance or substances by forcing these non-oxidizing
or non-oxidizable substances into the intercellular or interstitial spaces
of the metal by suitable pressure while the iron is in a properly heated
and expanded condition.
The following is one of the methods by which my Invention may be
successfully applied to the preservation of iron, as aforesaid. A vessel
of iron or any suitable material of sufficient strength and of the form
and size best adapted to the shape and dimensions of the iron article
to be treated is constructed with a lining of copper, zinc, or tin, or of any
suitable metal of a greater density or closeness of structure than iron.
This vessel is so constructed that it may be closed hermetically by the
top being screwed or clamped firmly down. At the bottom suitable
pipes are arranged for conveying steam and water alternately, as hercin-
after described.
This vessel is connected by a pipe or pipes with a power pump or
forcing apparatus for producing the necessary pressure. In the afore-
said vessel a proper quantity of pure paraffine is placed and heated to
the degree of heat necessary to bring it in to that fluid condition and
temperature best adapted to penetrate the intercellular or interstitial
spaces of the iron. This heat is obtained by passing steam through
the pipes arranged for that purpose, as above specified. The iron to
be treated having been previously heated to a degree slightly above
that given to the paraffine is now placed in the vessel containing
the latter, the lid is closed hermetically and pressure is applied to the
liquid or heated paraffine by means of the aforesaid power pump or
forcing apparatus, which forces the paraffine into the spaces of the
iron; the heat is kept up at the same time in order that the iron may
be in as expanded and porous condition as possible to receive the
paraffine in its intercellular or interstitial spaces.
After allowing the heated iron to remain a suitable length of time
in contact with and under pressure of the liquid paraffine the heat

page_text: is withdrawn by turning off the steam from the steam pipes, and
water of the proper temperature is passed through them to gradually
cool the iron, which upon cooling will be found to have retained
within its structure a sufficient quantity of the paraffine to render it
completely impervious to the action of oxidizing, corroding, or de-
composing substances.
An air pump may also be connected with the said vessel by which
a vacuum may be produced prior to the introduction of the melted
paraffine or other non-oxidizable substance or substances.
A compound of paraffine and a gum resin such as gum copal, gum
kowdic (known sometimes as Australian fossil gum), or other gum
resins of similar character mixed with purified "dead oil," or the heavy
oil distilled from petroleum (known as "solar oil" may be used with
advantage. A compound of the following proportions is highly valuable.
for the purposes described. To one gallon of purified "dead oil" add
two pounds of purified solid paraffine and two pounds of gum
kowdie.
It is desirable that the iron plates, pipes, castings, and other pieces
of metal to be treated should be thus saturated with a non-ozidizing
or non-ozidizable substance at the same time or immediately after
their manufacture, before the iron has cooled, and before the usual
scale or oxidation has formed; but this is not absolutely necessary
as they can be treated at any time by reheating and removing the.
scale. If this be done then the formation of scale or oxidation will
be prevented, and thus much greater value will be given to the iron by
reason of its non-oxidizable qualities imparted to it by the saturation
of its structure by a non-oxidizable substance.
After the saturation of the iron with paraffine or other non-oxidizable
substance under pressure and the cooling of the metal it is desirable
that the surface should be coated with a coating of good oil paint, or
marine paint, or with one or more of the ordinary saturated solutions
of resin, paraffine, or rubber in benzine, or with a solution of india-
rubber or gutta percha in melted paraffine, applied in a heated
condition.
I have found that a pressure of about one hundred and fifty or two
hundred pounds to the square inch, with a temperature of 300° to 350°,
with the above described apparatus will produce these desirable results;

page_text: but I do not confine myself to the above described apparatus, or to the
above named article of paraffine, or to any particular form of apparatus,
or to any one special non-oxidizing or non-oxidizable substance or
substances, or to any definite degree of temperature or definite amount
of pressure, as the requirements may vary with the different form of
article or quality of iron to be treated. I have found that many other
non-oxidizing and non-ozidizable substances (among which the hydro-
carbons are pre-eminent) will produce the result or afford the protection.
desired. I have found that a solution of paraffine in benzine, a solution
of resin in benzine, india-rubber in paraffine, gutta percha in paraffine,
a solution of gum copal and gum kowdie in crude petroleum, purified
crystalized naphthalene, a compound of purified naphthalene, with
purified "dead oil," a solution of wax in paraffine, and their com-
binations; also stearine and the animal oils will under the various
degrees of heat and pressure protect iron from oxidation.
Among the many useful purposes to which this method of protecting
iron from oxidation and corrosion can be most successfully applied,
and for which I claim especial adaptability and usefulness, is the
preparation of the iron plates, beams, nuts, screws, and bolts, used in
the building of iron ships. By saturating, as aforesaid, the plates and
beams before placing them in position, and then after they are in place
coating them with a coat of good marine or oil paint, or with a
saturated solution of paraffine, resin, and india-rubber in benzine, or
a solution of india-rubber and resin in melted paraffine, a complete
and durable protection is afforded against oxidation, rust, or corrosion,
from the outside by the action of salt or fresh water, and the inside
is protected against the action of bilge water and condensation of
moisture; thus one of the great objections to iron ships is removed
and an important branch of industry promoted and encouraged.
To the iron columns, beams, and roofs, used in house building the
above described process or method of protection from oxidation is
admirably adapted. In short this method of protecting iron from rust
or oxidation and corrosion is adapted for application to all articles
exposed to the action of moisture of the atmosphere, or to the direct
action of water, as in water pipes and other articles similarly exposed.
Having thus fully described my said Invention, and the manner of
performing the same, I wish it understood I am aware that a solution
paraffine in combination with other materials in benzine has been

page_text: occasionaly used with temporary benefit, but in these cases the solution
has been applied upon the surface like other varnish or paint, but my
Invention is of a radically different character, and I claim,-
First. The process of saturating or impregnating iron with a non-
oxidizing or non-oxidizable substance or substances under pressure
while the iron is expanded by heat.
Second. Paraffine, either separate or in combination with any non-
oxidizing or non-oxidizable substance or substances when subjected to
heat and applied to the iron under pressure, for the purpose specified.
In witness whereof, I, William Henry Sterling, have hereunto
set my hand and seal, this Fifth day of May, in the year
of our Lord One thousand cight hundred and seventy-three.