An Improved Process and Apparatus for the Manufacture of Artificial Stone.
Year: 1899

page_text: Date of Application, 15th Mar., 1899
Complete Specification Left, 15th Dec.. 1899-Accepted, 15th Mar., 1900
An Improved Process and Apparatus for the Manufacture of
Artificial Stone.
I, EMERY COULON, Manufacturer, of Blaton, Belgium, do hereby declare the
nature of this invention to be as follows:-
This invention relates to an improved process for manufacturing artificial stone
and also to the apparatus to be used in carrying out the process.
The process consists in crushing, following certain proportions and in such a
manner as to obtain an impalpable and homogeneous powder, a relatively weak
quantity of lime (either fat or hydraulic lime) or cement or dolomite with some
sand; the mixture is then put into trolleys which serve as moulds, that is to say
the trolleys are of the same dimensions as the stones to be manufactured; these
trolleys are run into a digester where they are submerged under water, introduced
there, and which is heated to a minimum temperature of 140° to 150° degrees
Centigrade, for at least 6 hours according to the product to be obtained; at the
same time, in order to facilitate the re-actions, an electric current is caused to
traverse the water in which the trolleys containing the mixture are submerged.
The re-action produced may be chemically stated as:—
Favoured by the heat, the dampness, and the electric current there is a formation
of calcareous silicate which causes those parts to adhere together which do not
participate in the re-action thereby producing a compact product, that is to say
a petrified mixture.
The digester into which the trolley-moulds are introduced is made somewhat
like a steam generator and surmounts a furnace and is provided with the usual
safety appliances. It possesses, upon its internal longitudinal walls, two rails
upon which the trolleys can be run in and out. At the two ends of the digester
the electrodes of an electric circuit project.
The digester is open at one end in order that the trolleys may be run in and
out and when a trolley is run into the digester the latter is hermetically closed
by a cover in the crown of which a screw thread is cut as well as in the corre-
sponding crown of the boiler; this screw thread is cut out upon three sixths of
each of the crowns. In order to close the digester the door is placed so that the
solid parts of its crown will correspond with the empty spaces of the crown of
the digester, the door is then pushed into place and given one sixth of a turn.
The trolleys which are provided with four large wheels for running upon the
rails of the boiler are made of sheet iron and have covers; they possess bands which
pass round the material and facilitate the removal of the stone, by means of any
kind of crane, after it has been finished and cooled. The walls of the trolleys
may be made double, the inner wall being extensible and the space between the

page_text: two walls being filled with sand in order that the material may be allowed to
expand during the re-actions. The vertical walls may also be jointed to the
bottom by hinges, and, after a trolley lias been filled, these walls may be held in
place by wire ropes stretched tightly round the body of the trolley by means of
drum and ratchet mechanism.
Tlated this 1441.
1000
An Improved Process and Apparatus for the Manufacture of
Artificial Stone..
I, EMERY COULON, of Blaton, Belgium, Manufacturer, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:—
Hitherto artificial stone has been produced by mixing either dry or moistened
sand and lime in suitable proportions, and submitting said mixture to the action
of steam or hot water for a longer or shorter time, generally 60 to 72 hours, with
the result of obtaining conglomerated products of coarse texture, more or less
resistance, more or less perfect homogeneousness, and the fracture of which does
not at all resemble that of natural stone.
Therefore a great many trials have been made without practical result for the
market, and artificial stone could not be generally employed as a substitute fort
other materials in construction, owing to the great expense of manufacture due
to several imperfect processes, by means of which an imperfect article could only
be produced.
The object of my present invention is to provide a process which may be
considered as a completion or an improvement of the process covered by Letters
Patent No. 23018 A.D. 1895. by means of which artificial stone may be produced
under the best industrial practical conditions, the structure and formation of
the produced artificial stone being identical with the geological structure of
natural stone, and my artificial stone having all the qualities of the latter.
The invention therefore involves (1) the special preparation of the raw materials;
(2) the petrification of such materials: and (3) the improved means or apparatus
for producing artificial stone.
In producing artificial stone the object is not to produce an ordinary con-
glomerated mixture of sand and lime, but to obtain a most perfect silicate of
lime. And, to produce chemical actions under good conditions, the ingredients
must be in a sufficiently divided state to allow of a perfect contact between the
materials, and the mixture of the latter must be most complete. The latter
condition is so much the more important, as two materials, sand and lime, of quite
different densities and having a tendency to separate during the manipulations
are employed for producing artificial stone.
Primarily, my improved process consists in mixing sand and lime in desired pro-
portions and submitting the mixture to perfect crushing within the same apparatus.
whereby I obtain an impalpable and well mixed material which is then treated
in another apparatus for producing artificial stone. The mixture being thus
impalpable and perfect, the product obtained after the manufacture represents a
silicate in a nearly pure state. The grain of the produced stone will be uniform.
the stone having a very fine fracture and being sharp-edged like natural free-
stone. The impalpable raw materials, settling more perfectly in the moulds.

page_text: produce a hard porous stone of slight porosity which qualities are always required
for building materials.
The moulds containing the mixture being introduced into the digesters, are
submerged under water raised to a minimum heat of 140 to 150° Celsius, and
remain therein during six hours at least, in accordance with the product to be
obtained. At the same time an electric current is passed through the moistened
mass for the purpose of promoting chemical action. The moulds are then with-
drawn from the digester and the mass is dried and cooled thus producing artificial
stone resembling natural stone and being of perfect homogeneousness and uniform
structure. My artificial stone cannot be injured or deteriorated by the hardest
frost or any inclemency of the seasons. On the contrary, it has been found that
the resistance thereof will be actually increased by the action of air.
The iniproved stone being perfectly homogeneous it may be easily cut and
is much better adapted to ornamental work than the best natural stone.
As said
stone may be coloured as desired by adding any suitable colouring matter, it
may be employed for producing agreeable effects in such ornamental work.
The effect of the electric current will be readily understood, since there are two
substances adapted to combine to produce a fixed compound or silicate of lime.
and the combination of such substances is effected under the best conditions.
chemical action may be represented as follows:-
CaO+SIO+ 2 H2O = Ca(OH) + H2SiO³=CaSiO³ + 2 H20.
The
It will be understood that the action of the electric current is to increase the
affinity of the substances under treatment. to produce ready and perfect petrifi-
cation and it will be noted that my improved process is important in fact, because
it requires a comparatively small proportion of lime or cement mixed with sand
which mixture by the foregoing treatment will set after a very short time.
In the accompanying drawings I have shown a suitable apparatus for carrying
out the above described process of producing artificial stone.
In these drawings:-
Fig. 1 shows a longitudinal sectional view of a digester, with a mould in place
therein, said mould being partly shown in section and partly in front elevation.
Fig. 2 is an end view of the digester.
Fig. 3 shows a cross-section of same, with a mould in place therein, said mould
being partly shown in cross-section and partly in side elevation.
Fig. 4 shows a partly plan view and horizontal section of the mould.
Fig. 5 shows a cross-section of the digester with a mould in place therein, the
walls of said mould being secured in a modified manner.
In the drawings like letters refer to like parts throughout all the figures.
The moulds serving to receive the mixture of the above named materials, are
constructed so that they may be employed as trucks, which allows of easily run-
ning them into the digester within which the chemical actions. are produced.
The walls of said moulds are suitably secured together, the front and back
supporting two wheels 7, which facilitate the entrance of the mould into the boiler,
said wheels running over rails i arranged within the digester (Fig. 1).
The top of the movable mould is removable and may be secured in place by
means of movable angle-irons (Figs. 1 & 3).
As the mixture has a tendency to expand during petrification, suitable means
have to be provided for avoiding adherence of the block to the stationary walls
of the mould I attain this result by arranging a mould with movable walls a
within the mould, the free space between said moulds being filled with sand
and secured by means of brace-plates as shown in Figs. 3 and 4. Furthermore
the removal of the block is facilitated by means of yoke-irons c, extending
around said block and terminating in eyes, to which the ends of the chains
of a crane may be readily attached. Thus the block may be removed without
having to take the outer casing to pieces the inserted sand preventing adherence
to the block.

page_text: Moulds with movable walls may however be employed, said walls being con-
nected with the bottom of the mould by means of suitable hinges (Fig. 5).
Before filling the mould, said walls are held together by means of two wire-ropes f¹,
extending around the mould and running in the transverse grooves of grooved
iron-bars g which latter are fitted on flat thin bent steel bars ', secured to and
projecting outwardly from the walls of the mould. Two of the walls carry grooved
pulleys provided with ratchets adapted to be engaged by pawls In the
groove of said pulleys are secured the ends of the rope at diametrically opposite
points, and said pulleys are integral with square headed pins adapted to receive
cranks by means of which the rope may be easily tightened upon the four vertical
walls of the mould. The above named pawls secure the tightening of the rope
by engaging the ratchets of said pulleys. The top of the mould may be secured
by means of bolts, or ropes attached to the bottom of said mould, or any suitable
device.
The grooved bars serve as guides for the wire ropes f¹ whilst the steel bars h¹
which support the bars g' are made with a certain amount of spring or elasticity
so as to tend to exercise a tightening pressure on the ropes.
In such moulds the joints must be made so that water is allowed to enter the
mouds, and the materials contained in the latter are prevented from pouring
through said joints. In other words, the moulds must have filtering joints, formed
of asbestos or several leaves of fine copper wire cloth, or asbestos inserted between
two leaves of wire-cloth.
The afore-named yokes are formed of three parts: a horizontal bar the ends
of which engage eyes formed on the lower ends of two vertical bars. The upper
ends of the latter have also eyes serving to receive the hooks of the crane-chain,
as already stated.
The digester a receiving the mould filled with the mixture is mounted and fitted
into stone-work (Fig. 1) like ordinary steam-boilers, said stone-work being
provided with flues for the passage of gas and smoke produced at the fire-box f
located underneath the digester. The latter is provided with all necessary attach-
ments, such as-safety-valves, water-gauge and manometer m.
The digester has a removable door for introducing and withdrawing the moulds:
to this end said door has outer screw-threads adapted to engage corresponding
threads provided in said boiler, said screw-threads being omitted over three
sixth of the peripheries, so as to have alternately threaded and plain portions.
If it is desired to close the boiler the plain portions of the inner boiler periphery
are made to register with the plain portions of the outer periphery, whereupon
the door is to be rotated for about one sixth of a revolution, whereby the closing
will be readily effected. A suitable packing may further be inserted so as to
secure the tightness of the joint.
Said door has passed through it an electric current wire p, insulated therefrom
by a suitable part : another current-wire pt passes through the upper wall of
the digester, said wire p being insulated by means of a suitable part t and suitably
connected with the mould the wire being connected with a copper plate 42
immersed in the water contained in the digester for the purpose above stated.
In practice I have found that the following proportions of the ingredients answer
well, viz.,
Sand
Lime
3
85 per cent.
15
"
Of course these proportions may be varied to a certain extent according to the
character it is desired to give the product.
If desired, in certain cases, cement or the like may be substituted for the lime,
and, also, in certain cases, ashes, scoriae, broken bricks or stones, may be sub-
stituted for the sand.
The mixture of sand and lime is placed in the moulds in a dry state and is not
rendered plastic by the addition of water. Steam, however, penetrates it when in
the digester.

page_text: As it is evident that many changes may be made in the construction and
arrangement of the above described apparatus without departing from the scope
and spirit of my invention, I wish it to be understood that I do not restrict myself
to the particular construction and arrangement of parts herein shown and described,
but that such changes and equivalents may be resorted to.
I wish it to be understood that I am aware that it has been proposed to make
artificial stone by heating a mass of sand, or other silicates and lime, cement or
the like, with steam or with hot water, or with water and steam and I make no
claim to any such process nor to any product derivable therefrom. Neither do
I claim, by this present patent the use of electricity in the manufacture of arti-
ficial stone, seeing that it is already patented in No. 23,018 A.D). 1895 herein-
before referred to, nor the crushing of the materials to an impalpable powder
except as part of the entire process described herein in conjunction with and
relating to my improved apparatus which apparatus is specially adapted to be
employed in the electrical process covered by Patent No. 23,018 A.D. 1895 herein
more completely set forth.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The improved process of producing artificial stone, by using an electric
current, wherein a mixture of sand, or other similar material, and lime, cement,
or the like is crushed so as to obtain a fine impalpable product, thoroughly mixed,
which is thereafter submitted in expansible moulds to the petrifying process sub-
stantially as described.
2. The improved apparatus for producing artificial stone, consisting of a digester
of any suitable, form and capacity adapted to receive the mould containing the
mixture and provided with means for readily closing it after the mould is run
into the same, substantially as herein before described and shown on the drawings
annexed.
3. The improved mould for producing artificial stone consisting of an outer
casing, and an inner casing, the latter having movable walls, substantially as
herein before described with reference to the drawings annexed and for the purpose
set forth.
4. The improved mould for producing artificial stone consisting of a preferably
rectangular casing, having movable side-walls and top, and means for readily
holding the said walls in the closed position, as more particularly described with
reference to Fig. 5, substantially as and for the purpose set forth.
Dated this 14th day of December 1899.
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.