Improvements in the Manufacture of Artificial Stone, and Apparatus therefor.
Year: 1896

page_text: This Print is in accordance with the Original Specification as it stands after.
Amendment (under Section 11 of the Patents, &c. Act, 1883), as required by
the decision of the Comptroller-General of the 17th day of August 1896.
.Date of Application, 19th Feb., 1896
Complete Specification Left, 24th Mar., 1896-Accepted, 9th May, 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Artificial Stone, and
Apparatus therefor.
A communication by LA SOCIÉTÉ ANONYME LA NÉO-LITHO, of Moll, near
Antwerp, in the Kingdom of Belgium, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street,
Manchester, both in the County of Lancaster, 118 New Street, Birmingham, in
the County of Warwick, and 31, High Holborn, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention to be as
follows:-
The manufacture of artificial stone, more particularly of sandstone in imitation
of the natural stone of France employed chiefly for fancy building, has up to the
present given rise to numerous processes and formulæ of manufacture, of which no
single one has been able up to the present to permit of an easy manufacture, or to
yield as a finished product a stone of the requisite cohesion.
The stones obtained up to the present were either too soft and friable and
offered an insufficient resistance or were too hard and in no way resembling
sandstone.
In the manufacture of sandstones the process hitherto employed to which the
subsiances were subjected, even if they were irreproachable in quality of
composition, did not enable the degree of cohesion desired to be obtained, and as
a consequence either friable products having no utility were produced, or there
were employed in the composition substances, which acting as agglutinants yielded
a hard product rather resembling cement than sandstone.
The process on which this improved manufacture is based has for its object to
produce sandstone of a very mingled texture and highly agglomerated, while
having the porosity characteristic of French stone, the process being in addition
capable of regulation in such a way as to yield products having a greater or less
cohesion, or in other words of greater or less powers of resistance to the action of
strains and stresses or compression.
In the construction of the improved sandstone when it has not to receive a
particular tint three elements only are employed, namely sand, lime and steam.
It is here pointed out that the use of sand and lime alone are not claimed as
anything novel, but the novelty consists as a principal point of the operation in
the use of steam alone as opposed to processes hitherto employed in which efforts
have been made to obtain the same result by the addition of a fourth element

page_text: namely water. In fact according to such processes the mixture of sand and lime
is first steeped in warm water and then subjected to the action of steam at a
pressure of 3 to 4 atmospheres. This method of working has never yielded
satisfactory results, the cohesion of the stones produced leaving always something
to be desired when only the two materials lime and sand were employed, and in
order then to give thein the necessary consistency, it was almost always necessary to
add thereto an agglutinant which took away from them the character of sandstone
and rendered their shaping or carving difficult and slow.
Although the use of steam alone forms a notable progression in this manufacture,
one capital point has hitherto escaped observation which consists in determining
the rational conditions under which steam must be utilized, but thèse conditions
are relative to the degree of pressure and even to the degree of temperature
under which steam must act. In fact the result of observations made is that if
the mass of sand and lime be subjected to the action of steam at 3 to
4 atmospheres the final product which results therefrom is still without the
qualities of resistance desired, whilst if the pressure be carried to 5 atmospheres
a stone is obtained equal in cohesion and resistance to the natural stone of France.
By carrying further the experiments on this line it has been established that under
a pressure of 6 atmospheres a more cohesive, harder and consequently more
resistant stone is obtained than natural stone, whilst at the same time such
artificial stone may be very easily tooled; and this proportion of solidity goes
on increasing with the higher number of atmospheres of pressure, which may go
on up to the possible limit determined by the chemical nature of the substance
under treatment. It may therefore be said that in view of a good manufacture
the minimum of pressure of the steam must be 5 atmospheres and that this
minimum is indispensable for obtaining products having qualities of a good
sandstone, and forming consequently the essential object of the invention with a
view to the result which cannot be realized without this condition.
In putting the hereinbefore mentioned process into operation a mixture varying
in proportions, but preferably of 90% of sand and 10% of lime is treated in the
following apparatus.
The apparatus consists essentially of a cylindrical boiler of such a length and
diameter as may be suitable for the masses or blocks of stone to be made, and the
sheet metal sides of which are of suitable thickness, one of which forms a
removable lid. In order to obtain an hermetically closed joint the edge of the
boiler and that of the lid is gripped in a strong cast metal ring, on which are cast
lugs open in the centre and opposite one another in order to receive in their
openings bolts which press the whole strongly together. At the bottom of the lid,
a bowl in a stirrup or other suitable arrangement is mounted, which enables the
lid to be withdrawn or approached with greater facility. Moulds which, with a
view to the formation of blocks of stone, receive a mixture of sand and lime, may
be put together and taken apart easily. They consist of bars and strong sheet
metal plates which are connected together by means of junction rods tightly
pressed up by means of wedges, and in order to facilitate the entrance of the
mould in the boiler, the two lower bars are provided with two pairs of rollers
which travel on a track formed at the bottom of the boiler and which is prolonged
to the outside of the same to a suitable distance. The moulds may be made of
any suitable dimensions by inserting intermediate partitions or plates.
Steam at high pressure (and finally water) is admitted into the boiler by four
openings by means of perforated tubes. It distributes itself therein in order to
penetrate by perforations in the plates of the moulds into the mixture therein
contained in order to convert it into hard stone, the plates being held apart by
interposed flat irons. The water of condensation formed during the operation
runs off by the discharge openings.
Dated th: 100

page_text: Improvements in the Manufacture of Artificial Stone, and
Apparatus therefor.
A communication by LA SOCIÉTÉ ANONYME LA NÉO-LITHO, of Moll, near
Antwerp, in the Kingdom of Belgium, Manufacturers.
I, WILLIAM PHILLIPS THOMPSON, F.C.S. M.I.M.E. of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool and 6 Bank Street,
Manchester both in the County of Lancaster, 118 New Street, Birmingham in the
County of Warwick and 31 High Holborn in the County of Middlesex, Civil
Engineer, 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 :-
The manufacture of artificial stone, more particularly of sandstone in imitation
of the natural stone of France employed chiefly for fancy building, has up to the
present given rise to numerous processes and formulæ of manufacture, of which no
single one has been able up to the present to permit of an easy manufacture, or to
yield as a finished product a stone of the requisite cohesion.
The stones obtained up to the present were either too soft and friable and
offered an insufficient resistance or were too hard and in no way resembled
sandstone.
In the manufacture of sandstones the process hitherto employed to which the
substances were subjected, even if they were irreproachable in quality of
composition, did not enable the degree of cohesion desired to be obtained, and as
a consequence either friable products having no utility were produced, or there
were employed in the composition substances, which, acting as agglutinants yielded
a hard product rather reseinbling cement than sandstone.
The process on which this improved manufacture is based has for its object to
produce sandstone of a very mingled texture and highly agglomerated, while having
the porosity characteristic of French stone, the process being in addition capable of
regulation in such a way as to yield products having a greater or less cohesion,
or in other words of greater or less powers of resistance to the action of strains and
stresses or compression.
In the construction of the improved sandstone when it has not to receive a
particular tint three elements only are employed, namely, sand, lime and steam.
It is here pointed out that the use of sand and lime alone are not claimed as
anything novel, but the novelty consists as a principal point of the operation in the
use of steam alone as opposed to processes hitherto employed, in which efforts have
been made to obtain the same result by the addition of a fourth element, namely
water. In fact according to such processes the mixture of sand and lime is first
steeped in warm water and then subjected to the action of steam at a pressure of
3 to 4 atmospheres. This method of working has never yielded satisfactory
results, the cohesion of the stones produced leaving always something to be desired
when only the two materials lime and sand were employed, and in order then to
give them the necessary consistency, it was almost always necessary to add thereto
an agglutinant, which took away from them the character of sandstone and
rendered their shaping or carving difficult and slow.
Although the use of steam alone forms a notable progression in this manu-
facture, one capital point has hitherto escaped observation, which consists in
determining the rational conditions under which steam must be utilized, but these
conditions are relative to the degree of pressure and even to the degree of
temperature under which steam must act. In fact the result of observations made
is that if the mass of sand and lime be subjected to the action of steam' at

page_text: 3 to 4 atmospheres the final product which results therefrom is still without the
qualities of resistance desired, whilst if the pressure be carried to 5 atmospheres
a stone is obtained equal in cohesion and resistance to the natural stone of France.
By carrying further the experiments on this line it has been established that
under a pressure of 6 atmospheres a more cohesive, harder and consequently
more resistant stone is obtained than natural stone, whilst at the same time such
artificial stone may be very easily tooled; and this proportion of solidity goes on
increasing with the higher number of atmospheres of pressure, which may go ou up
to the possible limit determined by the chemical nature of the substance under
treatment. It may therefore be said that having in view a good manufacture, the
minimum of pressure of the steam must be 5 atmospheres and that this minimum
is indispensable for obtaining products having qualities of a good sandstone, and
this forms consequently the essential object of the invention having in view a
result which cannot be realized without this condition.
In putting the hereinbefore mentioned process into operation a mixture varying
in proportions, but preferably of 90% of sand and 10% of lime is treated in the
following apparatus, which is shown in the accompanying drawing, Figure 1 being a
longitudinal section and Figure 2 a transverse section.
The apparatus consists essentially of a cylindrical boiler of such a length and
diameter as may be suitable for the masses or blocks of stone to be made, and the
sheet metal sides of which are of suitable thickness, the ends having a domed form,
one of which forms a removable lid D. In order to obtain an hermetically closed
joint, the edge of the boiler and that of the lid are each gripped in a strong cast
metal ring R, on which are cast lugs L open in the centre and opposite one
another in order to receive in their openings bolts B which press the whole
strongly together. At the bottom of the lid D, a roller R' is arranged in a
stirrup or other suitable arrangement, which roller enables the lid to be withdrawn
or approached with greater facility. Moulds which, with a view to the
formation of blocks of stone, receive a mixture of sand and lime, may be put
together and taken apart easily. They consist of bars T and strong sheet metal
plates P which are connected together by means of connecting rods V tightly
pressed up by means of wedges K and in order to facilitate the entrance of the
mould into the boiler, the two lower bars are provided with two pairs of rollers o,
which travel on rails S arranged at the bottom of the boiler and which are
prolonged to the outside of the same to a suitable distance. The moulds F
may be made of any suitable dimensions by inserting intermediate partitions
or plates.
Steam at high pressure is admitted into the boiler by four openings a b c d
by means of perforated tubes r. It distributes itself therein in order to penetrate
by perforations in the plates of the moulds into the mixture therein contained in
order to convert it into hard stone, the plates being held apart by interposed flat
irons. The water of condensation formed during the operation runs off by the
discharge openings o'. Steam is first admitted at a pressure of 2 or 3 atmospheres
until the mass is completely saturated, and the steam pressure is then raised to a
minimum pressure and temperature of 5 atmospheres (or higher according to the
degree of cohesion and hardness required for the stone which is to be made) this
high pressure being maintained until the operaton is completed.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I wish it to be understood that I am aware that it has
been proposed to make artificial stone by treating a mixture of sand and lime with
high pressure steam, I therefore make no claim for this process except when carried
out under the particular conditions set out below; but I declare that what I
claim is :-
1. A process for the manufacture of artificial stone, more particularly of sand
stone, characterized by the treatment of a mixture of sand and line in proportions

page_text: substantially as set forth, exclusively with steam, at a pressure of 2 or
3 atmospheres, until complete saturation of the mass, the steam pressure being
then raised and maintained up to the end of the operation at a minimum pressure
and temperature of 5 atmospheres, or at a higher number of atmospheres according
to the degree of cohesion and hardness of the stone which is to be made,
substantially as hereinbefore described.
Dated this 23rd day of March 1896.
WM. P. THOMPSON & Co.,
Agents.