Improvements in or relating to the Manufacture of Artificial Stone, Marble, and the like.
Year: 1898

page_text: Date of Application, 31st Oct., 1898
Complete Specification Left, 11th Aug., 1899-Accepted, 9th Sept., 1899
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Manufacture of Artificial Stone,
Marble, and the like.
A communication from PAUL ARTHUR JOSEPH GASSE, Proprietor, 32, Rue de la
Revolution, Colombes (Seine), Republic of France.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, do hereby declare the nature of this invention to be
as follows:-
This invention relates to the manufacture of artificial stone, marble and the
like from mixtures of sand with lime, or of ground marble with lime, and from
similar compounds.
One of the important features of the present invention is the employment of
the process or method hereinafter detailed whereby stone of superior quality is
produced within a period of lesser duration than that which is occupied by most
other processes of artificial stone manufacture.
According to this invention the process aforesaid is carried out as follows:-
Ingredients such as those above referred to are placed in moulds which are
then put into a closed chamber. A partial vacuum is next formed within that
chamber so that the air imprisoned among the particles or grains issues from the
mass of ingredients in the moulds. The next stage in the process is the treat-
ment of the contents of the moulds first with steam and then with hot water
under pressure, to slake the lime and bring about chemical changes in the
contents of the moulds. Finally, the water is withdrawn from the chamber
which is kept closed, and the contents of the mould therein are heated for a
suitable period, at the termination of which the moulds will be found to contain
a hard stone or marble.
During this last heating operation or as a preliminary thereto a vacuum may
again be formed in the closed chamber, the heating being effected by a hot
medium circulated through coils within the chamber. Or the chamber may be
filled with superheated steam or may have other hot gas circulated thorethrough,
to effect the final heating and drying operation.
The admission of steam in the slaking operation subsequent to the subjection
of the mass in the moulds to the action of the vacuum results in a quicker
initiation of the slaking action, which moreover is rendered more uniform and
complete under the joint action of steam and water as described than it would
by the action of water alone.
To effect the production of the vacuum in the closed chamber a vacuum pump
or other convenient means may be employed; a water vessel in connection
with the closed chamber may if desired be employed to serve also as a vacuum
chamber, steam being delivered into it and then condensed after which a con-
nection is opened between that vessel and the closed chamber, the air in the
latter expanding through the connection so that a partial vacuum is produced
[Prize 871

page_text: throughout the system. The condensation in the water vessel may be allowed to
take place by reason of radiation or the vessel may be fitted with a condensing
jet.
BOULT & WADE,
Agents for the Applicant.
Improvements in or relating to the Manufacture of Artificial Stone,
Marble, and the like.
A communication from PAUL ARTHUR JOSEPH GASSE, Proprietor, 32, Rue de la
Revolution, Colombes (Seine), Republic of France.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of London,
Chartered Patent Agent, 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 :-
This invention relates to the manufacture of artificial stone, marble and the
like from mixtures of sand with unslaked lime, or of ground marble or other
natural stone with unslaked lime, and from similar compounds.
The present invention consists in the employment of the process or method
hereinafter detailed whereby stone of superior quality is produced within a period
of lesser duration than that which is occupied by most other processes of artificial
stone manufacture.
A
According to this invention the process aforesaid is carried out as follows:-
Ingredients such as those above referred to, and of which unslaked lime is the
essential constituent, are thoroughly mixed in a dry state and preferably in a
more or less coarsely powdered condition, so that the various constituents are as
evenly distributed throughout the mass as possible, and the mixture placed in
moulds which are then put into a chamber which is capable of withstanding
internal and external pressure, and, when closed, is practically air tight.
partial vacuum is next formed within this chamber and maintained until the air
imprisoned among the particles or grains has issued from the mass of ingredients
in the moulds. The next stage in the process is the treatment of the contents of
the moulds first with steam preferably at a pressure of about 75 to 80 lbs. per
square inch and then with hot water under a pressure of 75 to 80 lbs. per
square inch to slake the lime and bring about the requisite chemical changes in
the contents of the moulds. The time during which the moulds and their con-
tents are subjected to the steam and water treatments varies with the size of the
blocks to be formed. If dealing with moulds having each a cubical content of
say 150 cubic feet the pressure of steam would be maintained for from three to
five hours and of water for eight to twelve hours.
The shape as well as the cubical content of the mould will also affect the length
of time required for effective treatment, a configuration which presents a large
surface relatively to the cubical contents requiring a shorter exposure than a
mould of equal content but smaller superficies. The essential point is that the
lime should be thoroughly slaked, and the precise time requisite to give the best
result can only be determined by practice.
Finally the water is withdrawn from the chamber which is kept closed, and
the contents of the mould therein are heated for a period requisite for the

page_text: thorough drying of the mass at the termination of which the moulds will be
found to contain a hard stone or marble.
During this last heating operation or as a preliminary thereto a vacuum may
again be formed in the closed chamber. The heating may be effected by a hot
medium circulated through coils within the chamber, or the chamber may be filled
with superheated steam or may have other hot gas circulated therethrough, to
effect the final heating and drying operation.
The admission of steam in the slaking operation subsequent to the subjection
of the mass in the moulds to the action of the vacuum results in a quicker
initiation of the slaking action, which moreover is rendered more uniform and
complete under the joint action of steam followed by that of water, as described,
than by the action of water alone.
To effect the production of the vacuum in the closed chamber a vacuum pump.
or other convenient means may be employed; a water vessel in connection
with the closed chamber may if desired be employed to serve also as a vacuum
chamber, steam being delivered into it and then condensed after which a con-
nection is opened between that vessel and the closed chamber, the air in the
latter expanding through the connection so that a partial vacuum is produced
throughout the system. The condensation in the water vessel may be allowed to
take place by reason of radiation or the vessel may be fitted with a condensing
jet.
Having now particularly described and ascertained the nature of the said
invention, as communicated to me by my foreign correspondent, and in what
manner the same is to be performed, I declare that what I claim is :-
1. The process for the manufacture of artificial store from materials of which
unslaked lime is an essential constituent comprising thoroughly mixing the
materials in a dry state, placing the mixture within a mould of the desired shape,
subjecting the contents of the mould to the action first of a partial vacuum
secondly of steam under pressure thirdly of hot water under pressure and finally
drying the mould and its contents by heat or by heat and the action of a vacuum
substantially as described.
2. The artificial stone manufactured by the process described in Claim 1.
1
T1
1000
BOULT & WADE,
Agents for the Applicant.