A PROCESS FOR OBTAINING DENSE AND FLAWLESS CASTINGS OF METALS AND SOLID BLOCKS OF OTHER SUBSTANCES, PARTICULARLY DESIRABLE IN THE PRODUCTION OF INGOTS FOR FORGINGS, HEAVY PIECES OF ORDNANCE. AND HYDRAULIC PRESS CYLINDERS
Year: 1864

page_text: LETTERS PATENT to George Bell and Robert Lüthy, both of Bolton, in
the County of Lancaster. Engineer's, for the Invention of "A PROCESS
FOR OBTAINING DENSE AND FLAWLESS CASTINGS OF METALS AND SOLID
BLOCKS OF OTHER SUBSTANCES, PARTICULARLY DESIRABLE IN THE PRODUCTION
OF INGOTS FOR FORGINGS, HEAVY PIECES OF ORDNANCE. AND HYDRAULIC PRESS
CYLINDERS."
Sealed the 25th April 1865, and dated the 14th November 1864.
PROVISIONAL SPECIFICATION left by the said George Bell and Robert
Luthy at the Office of the Commissioners of Patents, with their Petition,
on the 14th November 1864.
We, GEORGE BELL and ROBERT LUTHY, both of Bolton, in the County of
Lancaster, Engineers, do hereby declare the nature of the said Invention for
"A PROCESS FOR OBTAINING DENSE AND FLAWLESS CASTINGS OF METALS AND
SOLID BLOCKS OF OTHER SUBSTANCES, PARTICULARLY DESIRABLE IN THE PRODUCTION
OF INGOTS FOR FORGINGS. HEAVY PIECES OF ORDNANCE, AND HYDRAULIC PRESS
CYLINDERS," to be as follows:-..
It is well known that in the process of casting metals a considerable
quantity of air and gases are contained in the liquid mass, and that an addi-

page_text: tional quantity of air or other surrounding gas is carried by the force of the
stream with the metal into the moulds, and prevents the same from filling the
entire space provided for it. The castings thus contain what is known under
the name of "flaws," or air spaces, and the interior presents a spongy appear-
ance, though this may be in infinitely small dimensions. The air or gas
prevents the particles of the metal from intimately combining, and thereby
diminishes the strength of the casting. This, however, takes place not only
in casting of metals, but also in casting and forming of blocks or solid masses
of other substances. Where substances of a powdered, granulated, fibrous, or
otherwise finely-divided state have to be formed into blocks, it is chiefly the
air contained in and surrounding these small particles which prevents them
from being sufficiently united by pressure or otherwise, and from forming one
strong and solid mass.
In casting ingots or blocks of metals intended for forgings, it is not only
the mere presence of the air or gas itself which it is desirable to avoid; the
air or gas forms with the surrounding metal impurities, which prevent the
metal from being intimately united or welded in the process of forging or
pressing, and also from being of equal hardness throughout. To get rid of
this injurious presence and action of air and gases in the above-mentioned
operations, we now propose to exclude the admission of air or gases, and to
exhaust the same from the metal or other substance under operation, by
creating a partial, or, if possible, a complete vacuum in the moulds; and in
case of liquid substances also around the supplying stream from the furnace,
converter, ladle, or other reservoir. This we intend to do by any of the known
means for creating vacuums, as, for instance, exhaust pumps or fans.
In the casting of ingots of iron converted into steel by the "Bessemer
process,"
," patented 8th January 1862, No. 56, we propose to effect our purpose
by forming an air-tight connection between the tapping hole of the ladle and
the ingot moulds in such a manner that the same can easily be applied to a
succession of moulds. Such a communication can easily be established by the
use of some pliable substance, as india-rubber, leather, clay, or sand, adapting
itself to the shapes and uneveness of the top of the mould and the bottom of the
ladle when brought towards each other. In connection with the top of the mould,
ora hollow projection of the ladle bottom round the tapping-hole, or an interme-
diate piece between the ladleaud the mould, is a pipe in communication with the
exhausting apparatus. If required the air or gas can be led through a cooler,
so that it does not reach the exhauster in too hot a state; we either lower
the ladle on to the moulds, or raise the latter to meet the ladle. To ascertain
when a mould is filled we propose to place the same on a weighing apparatus,

page_text: or to have such an apparatus in connection with the ladle, or also to place a
glass-covered peep hole in a pipe in such a position that the top of the ingot
can easily be seen. Instead of having an air-tight communication between
the mould and the tapping hole in the ladle, we also propose to place a kind
of funnel on the top of the mould to receive the metal from the ladle, the
exhaust pipe being in communication with the interior of the mould. If the
metal is delivered in a little greater quantity then the funnel will pass into
the mould, a vacuum will easily be created inside, the only opening commu-
nicating with the outer air being stopped up by the entering metal. All parts
in the immediate neighbourhood of the molten metal can be protected by
some fire-proof substance.
We apply our process in the same manner to the casting of cast steel,
cast iron, gun metal, or any other metal, in all cases, however, with such
alterations in the apparatus as to suit circumstances.
In casting heavy pieces of ordnance, hydraulic press cylinders, and any other
articles, we proceed in a similar way as above described, and to suit the same
apparatus to different sized & shaped moulds, we propose to use air-tight pits
or tanks with removable covers, in which the entire mould or a number of
moulds can be placed and the air therefrom exhausted, there being no com-
munication with the exterior except through the inlets for the metal.
Our process is applied in a similar way to casting of plaster, india-rubber,
and similar substances. In the production of blocks of other substances as,
for instance, bricks of clay, or of sand and lime, or cinders, blocks of artificial
stone, of artificial fuel made from small coal, peat, waste wood, blocks of wood
from small divided wood, bales of cotton, wool, hay, and similar substances,
the exhausting of the air before and during the process of pressing will be of
great advantage.
Where bricks or blocks of substances in a powdered or granulated state,
like sand, clay, or small coal are pressed in moulds, we propose to perforate
the sides of the moulds, and if necessary also the stamp and the bottom of the
mould, and bring these perforations into communication with an exhaust
pump, so that all the air amongst the particles of the substance to be com-
pressed is expelled during the operation of pressing. As some of the material
may then fill up the perforations, we propose to employ the same air pump or
a separate one to force these particles back again by compressed air when the
moulds are empty

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Bell and Robert Luthy in the Great Seal Patent
Office on the 12th May 1865.
•
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, GEORGE
BELL and ROBERT LUTHY, both of Bolton, in the County of Lancaster,
Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of November, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto us,
the said George Bell and Robert Luthy, Her special licence that we, the
said George Bell and Robert Luthy, our executors, administrators, and
assigns, or such others as we, the said George Bell and Robert Luthy,
our 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 "A PROCESS FOR OBTAINING
DENSE AND FLAWLESS' CASTINGS OF METALS AND SOLID BLOCKS OF OTHER SUB-
STANCES. PARTICULARLY DESIRABLE IN THE PRODUCTION OF INGOTS FOR FORGINGS,
HEAVY PIECES OF ORDNANCE, AND HYDRAULIC PRESS CYLINDERS," upon the condi-
tion (amongst others) that we,the said George Bell and Robert Luthy, our
executors or administrators, by an instrument in writing under our, or
their, or one of our or 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.
NOW KNOW YE, that we, the said George Bell and Robert Luthy, do
hereby declare the nature of our said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
It is well known that in the process of casting metals a considerable
quantity of air and gases is contained in the liquid mass, and that an addi-
tional quantity of air or other surrounding gas is carried by the force of the
stream with the metal into the moulds, and prevents the same from filling the
entire space provided for it. Thus castings contain what is known under

page_text: the name of "flaws," holes, or pores, which give the interior a cellular or
spongy appearance. Although these holes or pores may be infinitely small,
yet their large number will greatly diminish the strength of the castings;
this however takes place not only in the casting of metals, but also in the
casting and forming of blocks or solid masses of other substances. Where
substances of a powdered, granulated, fibrous, or otherwise finely-divided state
have to be formed into blocks, it is chiefly the air contained in and surround-
ing these small particles which prevents them from being sufficiently united
by pressure or otherwise, and from forming one strong and solid mass.
In casting ingots or blocks of metals intended for forgings, it is not
only the mere presence of the air or gas itself which it is desirable to avoid,
but the air or gas forms with the surrounding metal oxides or other impu-
rities which prevent the metal from being intimately united or welded in the
process of forging or pressing, and also from being of equal hardness through-
out. To avoid this injurious presence and action of air and gases in the
above-mentioned operations, we propose to prevent their admission, and to
exhaust the same from the metal or other substance under operation, by
creating a partial, or if possible, a complete vacuum in the moulds, and, in
case of liquid substances, particularly around the supply stream from the
furnace, ladle, or other reservoir. This we intend to do by any of the
known means for creating a vacuum, as, for instance, by exhaust pumps or
fans.
In order that our Invention may be more fully understood and readily
carried into effect, we will now proceed more particularly to describe some of
its applications, refercuce being had to theannexed Sheet of Drawings, and to
the figures and letters marked thereon.
Ingots cast of iron, converted into steel by the "Bessemer process," as
described in the Specifications of Letters Patent granted to Henry Bessemer
viz, No. 630 of 1856, No. 578 of 1860, No. 50 of 1862, and others are
particularly liable to contain a large number of blow-holes or pores, the
formation of which may be ascribed to different causes. Some of the holes
are caused by air brought into the metal the blowing process in the con-
verter, or carried into the same by the stream in pouring from one vessel into
another, as from the converter into the laddle and from the laddle again into
the moulds; these holes are probably the most injurious, as their inner surfaces
become oxidised, and cannot be welded together in the process of forging.
Other holes or blisters arise from gases formed by the contact of the hot
metal with the impure sides of the moulds. Holes are also supposed to be
formed from gases taken up by the metal when under very high temperature,

page_text: and ejected again under solidifying. Vacuum spaces are also formed by the
contraction of the metal when cooling; the outer parts of the ingots having
become hard are unable to follow the interior parts when contracting, and
the latter thus tear away from the former at different places; these latter
holes are less injurious, as their surfaces are very clean and easily weld
together in forging. It is our object to prevent the formation of these holes
as much as possible, and to produce dense castings, which, if intended for
forging, will save a great amount of labor and fuel in this operation.
Articles requiring to be made of strong and dense material, as, for instance,
pieces of ordnance, shot and shells and hydraulic press cylinders, may, under
our improved process, be cast of "Bessemer metal, which as at present cast
will not admit of being applied to such purposes with safety. To attain this
object, we propose to apply a vacuum around the stream of metal imme-
diately before it enters the mould in order to prevent the admission of air
which is usually carried into the metal by the stream, and to extract the air
and gases already contained in the metal, and which are not able to disengage
themselves from the same under the pressure of the atmosphere. We prevent
the admission of air, and form a vacuum at this particular point, as it is here
that the greatest surface of the metal is exposed to the air in the usual mode
of casting, the whole of the metal having to pass in a thin stream. It is also
at this point that we can best take advantage of the large surface exposed to
extricate the air and gases contained in the metal; any gases forming in the
mould are constantly exhausted as the metal rises in the same.
Figs. I., II, & III. show. arrangements as applied for casting ingots of
Bessemer metal. 1 represents the casting ladle lined with fire-proof sub-
stance, and usually placed on the end of a hydraulic rotary crane 2; in the
bottom of the ladle is the tapping apparatus, consisting of a cylinder 3 of fire-
clay, set and fastened in a box 4 secured to the bottom plate of the ladle; a
stopper 5, also of fire-clay, connected through an elongation 5ª of its upper
end is bent over the top of the ladle to a land-lever arrangement 6,by which it
can be raised or lowered ou to the seat. The stopper 5 is usually simply ball-
shaped, and has no elongation reaching into the cylindrical outlet hole. For
the purpose of leading the metal in very thin streams through the vacuum,
we propose to apply a stopper similar to what is shewn in Fig. I., and ou a
larger scale in Fig. III. The stopper projects downwards into the outlet
hole, and is fitted with grooves all around through which the metal has to
pass, thus running into the moulds in flat thin streams, the metal presenting
a very large surface to the action of the vacuum. It is not necessary that the
stopper and tapping hole should be round and cylindrical, they may be of

page_text: any other form. 7 represents a vacuum chamber connecting the ladle with
the mould, in this case fastened to the ladle bottom, and made air-tight with
the top of the mould by some pliable substance as clay or sand, adapting itself
to the unevenness of the parts which have to form an air-tight joint during
the casting. A pipe 8 connects the vacuum chamber 7 with the exhausting
apparatus, and if necessary may be led through a water cistern placed on the
crane, in order that the gases may not reach the exhauster in too hot a state.
Instead of having an exhaust pump on purpose, the blowing engine, used for
blowing the metal in the converter, may be made use of simply by connecting
the pipe 8 with the suction pipe of the engine, and shutting off the supply
from the outer air. A tube 9 is also connected with the chamber 7, having
in its end a glass-covered press hole through which the operator may see when
the mould is full; 10 is the mould hooped in the usual way.
In Fig. I. the mould has a flange near the top on which the vacuum
chamber rests, the top of the mould being provided with lugs; Fig. II.
shows a vacuum chamber with a broad flange at its lower end to suit different
sized moulds, which in this case must be even on the top with lugs at the
sides; it is not absolutely necessary that the vacuum chamber be fixed to the
ladle bottom. The vacuum chamber may also be fitted with a funnel lined
with fire-clay, and provided with a tapping apparatus similar to the one,
above described, in connection with the ladle. This chamber may be placed
on a mould and the metal run in from the usual casting ladle; this may be
of particular advantage for very large ingots requiring more than one ladle
full of metal, as the connection between the chamber and the mould will not
have to be disturbed, and the vacuum can be kept up until the casting is
complete. To ascertain when a mould is full it may be placed on a weighing
apparatus, or such an apparatus inay be connected with the ladle to indicate
the quantity discharged. To bring the ladle, vacuum chamber, and mould
into close contact the ladle may be lowered, or the mould raised. If an
independant vacuum chamber with a funnel on the top is used for smaller
moulds which can be filled from one ladle, the tapping apparatus need not
be applied to the funnel. If the supply from the ladle is a little greater than
the discharge into the mould, a vacuum can casily be maintained during the
operation of casting, as the only communication between the mould and the
outer air is stopped up by the metal itself.
We apply our process in a similar manner to the casting of cast steel, cast
iron, copper, or any other metal; in all cases, however, with such alterations
in the apparatus as may be found necessary to suit circumstances.
In casting heavy pieces of ordnance, hydraulic press cylinders, shot, and any

page_text: other articles, we proceed in a similar way as above described, and to suit the
same apparatus to different sized and shaped moulds, we propose to use air-
tight pits or tanks with removeable covers, in which the entire mould or a
number of moulds can be placed, and the air exhausted therefrom, there being
no communication with the outer air except through the inlets for the
metal.
Fig. IV. represents such an arrangement for casting articles in air-tight
chambers. A tank a, a, which may be made of several parts, is shown let
into the ground with a mould b for a gun placed in it. The exhaust pipe c
is fastened to the removeable cover d, on which is also placed the inlet
funnel e, in this case provided with a stopper f, so that the air may be
exhausted from the mould and tank before metal is run in. A
peep hole
may also be provided, so that the level of the metal in the mould may be
ascertained.
In the production of blocks of other substances, as for instance bricks of
clay or of sand and lime, blocks of artificial stone, artificial fuel made from
small coal, peat, waste wood, blocks of wood from small divided wood, bales
of cotton, wool, and similar substances, the exhausting of the air before and
during the process of pressing will be of great advantage.
Where bricks or blocks of substances in a powdered or granulated state
like sand, clay, and small coal are pressed in moulds, we propose to perforate
the sides of the moulds, and if necessary also the faller and the bottom plate,
and bring these perforations into communication with an exhaust pump, so
that all the air amongst the particles of the substance to be compressed is
expelled during the operation of pressing. As some of the material may then.
fill up the perforations, we propose to employ the same air pump, or a
separate one to force these particles back again by compressed air when the
moulds are empty.
Having now described the nature of our said Invention, and the manner
in which the same may be carried into effect, we wish it to be understood
that we do not confine or limit ourselves to the precise details and arrange.
ments as shewn and described, as the same may be modified according to the
purposes for which they are to be applied; but what we do claim as the
Invention to be secured to us by the herein-before in part recited Letters
Patent, is,―
Firstly, the application of a vacuum around the stream entering the moulds
in the process of casting metals, in the manner and for the purpose sub-
stantially as herein-before described.
Secondly, the apparatus consisting of parts 4, 5, 7, 8, and 9 of Figs. I,

page_text: II., and III., and the modifications of the same, substantially as shewn and
described.
Thirdly, the use of vacuum chambers or tanks and parts combined there-
with, in the manner and for the purpose substantially as herein described and
shewn in Fig. IV.
Fourthly, the application of a vacuum in the formation of blocks of artificial
stone or of other substances, in the manner and for the purpose substantially
as herein described.
* In witness whereof, we, the said George Bell and Robert Luthy, have
hereunto set our hands and seals, this Eleventh day of May, in the
year of our Lord One thousand eight hundred and sixty-five.