IMPROVEMENTS IN THE PROCESS OF MAKING MALleable Cast IRON. AND IN APPARATUS THEREFOR.
Year: 1872

page_text: LETTERS PATENT to Albert Franklin Andrews, of the City and
County of New Haven, in the State of Connecticut, United States of
America, for the Invention of IMPROVEMENTS IN THE PROCESS OF
MAKING MALleable Cast IRON. AND IN APPARATUS THEREFOR.
MAKING MALleable Cast IRON. AND IN APPARATUS THEREFOR.

page_text: or carbonic acid is associated also with lime, oxide of iron, or other
metallic bases, either separately or mixed, and in another with clay,
silica, or the silicates.
The castings are produced in the ordinary manner from the ordinary
varieties or mixtures of iron suitable for being subsequently made
malleable. It will be understood that they are small; but larger sizes of
castings may be successfully treated, with proper care, by subjecting the
castings for a longer time to the influence of chemicals and heat. The
treatment requires a hot furnace with means for varying the temperature,
so that it may be raised toward the latter portion of the treatment of
each batch, but which it is intended to keep continuously hot for a long
period, a cooling pit or space in which the walls may be allowed to
remain at a moderate temperature, provisions for manufacturing or
supplying hydrogen gas, a store of lime and the other materials, and a
quantity of cases peculiarly adapted to each other and to the furnace
to form a series extending along within the furnace, through which the
hydrogen gas may be passed to expose the castings which are properly
disposed therein to the influence thereof.
The convenient working of the process requires also strong grapples
adapted to reach into the furnace, and to take hold of the portable cases
and cranes overhead railways, or analogous means for conveniently
moving the hot masses from the furnace to the cooling pits.
The hot furnace with its surrounding masonry is kept at a high
temperature by means of a fire underneath or at the side. This is
successfully accomplished with a fire worked like a puddler's fire, or
what is sometimes called a reverberatory furnace.
I employ cases made of fire-clay or other suitable material of a
rectangular form, and provided with either a fixed or a removable false
bottom which is perforated. Below this false bottom there is an orifice
at each side or end of the case, one of which is provided with a pro-
jecting nozzle adapted to match into the corresponding hole in the
adjacent similar casing. The small castings to be made malleable are
packed down in the space above the perforated bottom with the irregular
spaces between filled with finely divided lime. The top is covered by a
luted cap, having a small hole near the centre, by which hole the gas
rising through the interstices in the lime may escape through a tube
which is attached after the case and its contents are in position in the

page_text: furnace. The tube may be of a small size; its function is to lead the
gas to a convenient point above and outside the furnace where the small
current of escaping gas may burn continuously, and indicate to the
experienced eye the progress of the work.
Hydrogen is applied from a suitable reservoir through a pipe or other
channel to one end of the furnace, and allowed to flow into the furnace
and into the space below the false bottom in which the gas is. A portion
flows upward through the contents of each case, and escapes in a more
or less modified condition at the top. It usually escapes charged with
carbon derived from the iron castings which it passes in percolating
upward through the lime. In other words it escapes as a hydrocarbon,
and burns with a tolerably luminous light on emerging from the small
tube.
Provision is made in the construction of the cases for retaining either
within the hole which receives the gas, or around the nozzle at the
opposite side or end of each case where the gas passes out a ring of
properly moistened and plastic clay to serve as a luting. I prefer to
apply clay in both the positions named. When the cases are lowered
into their proper positions in the furnace, they are moved endwise succes-
sively so as to thrust the nozzle of one into the hole in the other, and
the luting makes an approximately gas-tight joint.
It will be understood of course that the commencement of the series is
properly luted to make a tight connection with the furnace and with the
pipe which supplies the gas. I prefer also to connect a pipe to the
other end of the furnace, and to cause a current of gas to flow not only
into and along the whole series of cases under the false bottom in each,
but also to circulate quite through the last member of the series and out
through a pipe which connects to the corresponding end or side of the
furnace. I have found that the effect is about the same if instead of
pure hydrogen I use the same largely mixed with carbonic oxide, such
as results from the manufacture of hydrogen by passing steam through
a red hot bed of charcoal.
A chemical combination of the hydrogen with any other element
which retains it with much tenacity under heat is to be avoided.
It is important to present the hydrogen in a free or nearly free
condition to allow it to produce the proper action. Air-slacked lime is a

page_text: aluminum.
It is preferable to have oxygen in the packing material and in such
condition as to be ready to yield it up when required. To this end it is
well to wet the oxide of iron with a solution of common salt or a nitrate
or chlorate-of potash in water, after each use to-reoxydize the partially
deoxydized material and make it fresh for further use. Oxides of other
metals than iron may also be used. The main function of the packing
material is to afford a support to the castings to reduce the risk of their
becoming much distorted at a high temperature under the pressure
which they exert on each other, and to allow the access of the gases to,
and the free escape of the carbon from the castings.
T
The furnace is maintained at a high temperature for a few hours, and
the temperature raised for a brief period toward the close of the
operation, and then the furnace having been allowed to cool a little the
cases and their contents are lifted out by means of suitable grapples and
are carried on a crane or otherwise to be deposited in a cooling pit. Six
to ten hours are sufficient for ordinary small castings, such as door
latches, parts of gun locks, and the like. After remaining in the cooling
pit at a moderately high but slowly decreasing temperature for about
twenty-four hours, the cases and their contents may be removed to
make way for others, and left in the open air where they will reach the
cooling point more rapidly.
A great part of the good effect of my Invention may be realized by
submitting the material to the action of the hydrogen as above described
only a portion of the time, and in the interval supplying a stream of
other gas to flow through the channels above indicated. I beleive it
better to thus alternate the currents of gas under some conditions using
always a gas which is neutral in its effects on the iron. As the
alternating gas carbonic acid or carbonic oxide are to be preferred partly
from the greater facility with which these gases can be produced, one
hour for each is a suitable period. The effect will be more uniform if

page_text: the operation is conducted by this alternating use of the gases, although
the process will probably require a little longer time than when
hydrogen is all the time present.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Albert Franklin Andrews in the Great Seal Patent
Office on the 5th September 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALBERT
FRANKLIN ANDREWS, of the City and County of New Haven, in the
State of Connecticut, United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of March, in the year
of our Lord One thousand eight hundred and seventy-two, in the
thirty-fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Albert Franklin Andrews, Her special
licence that I, the said Albert Franklin Andrews, my executors,
administrators, and assigns, or such others as I, the said Albert
Franklin Andrews, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN THE PROCESS OF MAKING MALLEABLE CAST
IRON, AND IN APPARATUS THEREFOR," upon the condition (amongst others)
that I the said Albert Franklin Andrews, my executors or adminis-
trators, by an instrument in writing under my; or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.

page_text: same is to be performed, to be particularly described and ascertained in
and by the following statement :-
I subject the castings to the influence of hydrogen or its compounds,
either alone or associated, or alternated with carbonic oxide or acid at a
certain temperature. In one modiycation of the Invention the hydrogen
or carbonic oxide or carbonic acid is associated also with lime, oxide of
iron, or other metallic bases, either separately or mixed, and another
with clay, silica, or the silicates.
The accompanying Drawings form a part of this Specification.
Figure 1 is a vertical section through a portion of the furnace, show-
ing the cases in position; Figure 2 is an end view of one of the cases
detached; Figure 3 is a cross section of the case; Figure 4 is a longi-
tudinal section through an entire furnace on a smaller scale; and
Figure 5 is a plan view of the arrangement; it is a horizontal section
in the plane of the connecting nozzles. Similar letters of reference
indicate corresponding parts in all the Figures.
The castings are produced in the ordinary manner from the ordinary
varieties or mixtures of iron suitable for being subsequently made
malleable. It will be understood that they are small; but larger sizes
of castings may be successfully treated, with proper care, by subjecting
the castings for a longer time to the influence of the chemicals and heat.
The treatment requires a hot furnace with means for varying the tem-
perature, so that it may be raised toward the latter portion of the treat-
ment of each batch, but which it is intended to keep continuously hot
for a long period, a cooling pit or space in which the walls may be
allowed to remain at a moderate temperature, provisions for manu-
facturing or supplying hydrogen gas, a store of lime and the other
materials, and a quantity of cases peculiarly adapted to each other and
to the furnace to form a series extending along within the furnace,
through which the hydrogen gas may be passed to expose the castings
which are properly disposed therein to the influence thereof.
The convenient working of the process requires also strong grapples
adapted to reach into the furnace, and to take hold of the portable cases
and cranes, overhead railroads, or analogous means for conveniently
moving the hot masses from the furnace to the cooling pits.
Referring to the Drawings, A, A, are the stationary walls of the hot
furnace. The inclosed space, it will be understood, is kept at a high tem-

page_text: perature by means of a fire underneath or at the side, not represented.
I have experimented successfully with a fire working like a puddlers'
fire, or what is called a reverberatory furnace. B, B, are cases made of
fire-clay or other suitable material of a rectangular form, and provided
either with a fixed or with a removable false bottom B₁, below which
there is an orifice at each side, one of which is provided with a project-
ing nozzle adapted to match into the corresponding hole in the adjacent
similar casing. The castings to be treated are packed down in the space
above the perforated bottom, with the irregular spaces between filled
with finely divided lime; and the top is covered by a luted cap B²
having a small hole 6 near the centre, through which the gas rising
through the interstices in the lime may escape through a tube C, which
is temporarily attached after the case B and its contents are in position
in the furnace. The tube C may be of small size. Its function is to
lead the gas to a convenient point above and outside of the furnace,
where the small current of escaping gas may burn continuously and
indicate to the experienced eye the progress of the work. The hydrogen
is supplied from a suitable reservoir, not represented, through the pipe D
to one end of the furnace, and maintained at a moderate pressure. It
flows through the vacant space below the false bottom in each of the
cases B, and a portion flows upward through the contents of each case
to escape in a more or less modified condition at the top. It usually
escapes as a hydrocarbon. Provision is made in the construction of the
cases B for retaining either within the hole which receives the gas or
around the nozzle at the opposite side or end of each case a ring of
properly moistened and plastic clay to serve as a luting. I prefer to
apply clay in this manner in both the positions named. When the cases
are lowered into their proper positions in the furnace A, they are moved
endwise successively into the proper position to thrust the nozzle of one
into the hole in the other, and the luting makes an approximately gas-
tight joint.
It will be understood of course that the termination of the series at
each end is properly luted. I prefer to connect a pipe to the other end
of the furnace, and to cause a current of the gas to flow not only into
and along the whole series of cases B, but also to circulate quite through
the last number of the series and out through the pipe which connects
to the corresponding end or side of the furnace. The effect is about the
same if instead of pure hydrogen I use the same largely mixed with

page_text: A great part of the beneficial results can be obtained with hydrogen
or compounds yielding hydrogen under heat, like ammonium or others,
together with the alternate or combined use of carbonic oxide or acid
gases, as in making it with charcoal, anthracite, coke, peat, or other
carbons to decompose water, as they will all do it, charcoal and peat
being best because free of sulphur.
Instead of the above specific construction of the apparatus I
contemplate using a retort to open at the end to load and unload the
furnace, or if the furnace is used without it I may load and unload at
the end instead of the top, using a fork to run under the boxes between
the legs, said fork being mounted on rollers on which the boxes are
lifted and drawn out of the retort or furnace and rolled to any desired
place for cooling where a cover of sheet iron or any other material can
be placed over each to cool slowly, somewhat as if in a cooling pit.
The hydrogen will be furnished to the portable cases or boxes by a tube
from the charcoal box running the whole length of the retort or furnace
occupied by the portable cases, with a hole in this tube for each case,
and also a hole in the bottom of each case to admit the hydrogen
under the false bototm of the case. The cases only have to be run
into the furnace or retort and 'dropped on to the hole which can be
luted or not as may be desired, the necessity of which will depend on
the question whether the retort is tight or not. If the open furnace or
fire-pit is used luting will be necessary.

page_text: 5th. The pipes C connected to the portable cases as shown and
arranged to serve as an exit for a small stream of gas from each, as and
for the purposes set forth.
6th. The loading and unloading of the furnace at a high or heated
temperature, substantially in the manner herein set forth, so as to render
its operation continuous for an indefinite period.
7th. The depositing of the hot castings in a cooling receptacle, as
and for the purposes hercin set forth.
In witness whereof, I, the said Albert Franklin Andrews, have
hereunto set my hand and seal, this Nineteenth day of June,
in the year of our Lord One thousand eight hundred and
seventy-two.
ALBERT FRANKLIN ANDREWS. (L.S.)