Improved Apparatus Employed in the Manufacture of Artificial Sandstone.
Year: 1891

page_text: The decision of the Comptroller-General, of the 16th day of October 1893, allowed,
under Section 18 of the Patents, &c. Act, 1883, an Amendment of this
Specification.
COMPLETE SPECIFICATION (AMENDED).
[Communicated from abroad by Dr. FRIEDRICH ZERNIKOW, of Oderberg in Mark,
Germany.]
Improved Apparatus Employed in the Manufacture of Artificial
Sandstone.
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents 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 :-
In every application of burnt pulverulent lime in the manufacture of artificial
stone, it is necessary to provide means for resisting the expansion thereof on slaking,
if it be desired to prevent any alteration in the form of the stone to be produced.
In particular this is necessary in the process in which pulverised burnt lime is
mixed dry with sand, slag powder, or other siliceous substances, then rammed into
moulds and subjected to the action of high pressure steam, so as to effectually slake
the lime; during this operation the expanding action of the slaking lime must be
effectually resisted, so that the moulds may not be burst or bulged outwards, the
lime being thus forced to penetrate thoroughly into all the interstices between the
granules of sand, so as, after hardening, to produce a perfectly hard dense cohering
mass
According to the present invention, the requisite resistance to the expansion of
the lime is afforded by enclosing the charged moulds in a strong casing, the interior
of which is subjected to the pressure of high pressure steam which, being exerted
against the outer surfaces of the moulds, will effectually-resist any bulging or
bursting action of the lime. When the moulded objects to be produced are not of
such large dimensions that a single mould fills the said casing more or less entirely,
such as large columns, it is, for the sake of economical production, desirable to
arrange the moulds for the objects that are most used, such as building blocks, slabs,
steps, cornices &c. so that they can be packed closely together within the casing, in
order that the sides that are in contact may afford each other mutual support
against the expending action, and may consequently be made less strong than would
otherwise be necessary.
As is well known, the circular form is the only one that resists any deformation
by an expanding pressure exerted uniformly in every direction such as that
exercised by the slaking lime.
On this principle is constructed the apparatus for carrying out the said operation
as shewn on the accompanying drawings, in which Fig. 1 shews the elevation of a
vertically arranged cylindrical steam chamber A which can be raised in a vertical
position from off the base D by a winch or crane by means of the ring B at top.
To the lower end is rivetted an annular flange by means of which it rests upon
the base D, to which it may be secured by screw bolts a a, with an intervening
packing if necessary, for forming a steam tight joint.

page_text: 4
The steam chamber is provided with a branch pipe (not shewn in the drawings)
by which it is connected to a steam generator, as also with a water gauge and
pressure gauge. The water condensing in the chamber is led off at bottom through
a pipe b to a steam trap G from which it can be discharged from time to time.
The moulds containing the material to be treated with steam are placed within
this chamber, such moulds being arranged as shewn in plan and elevation at
Figs. 2 and 3.
The size and arrangement of the moulds may be variously modified; by way of
example, there are here shewn four main moulds of which two are, say, 50 cm. wide,
and 20 cm. high and the other two 90 cm. wide and respectively 30 cm. and 28 cm.
high, while the length is determined by the length of the chamber, which in the
present case is supposed to be 150 cm. All the main moulds or boxes are made of
galvanized or tinned sheet iron secured by screw bolts at the edges. The principal
moulds have to be so made that when placed together they can be embraced by
the rings F F Fig. 2, which may be of iron or steel.
Assuming that one of the smaller moulds be laid down flat, it will present a cubic
capacity of 150 cm. by 50 cm. by 20 cm, to be charged with the compound; if this
capacity be divided in its width by the introduction of two parallel plates running
in the direction of the length, three equal compartments will be formed of 150 cm.
length, 20 cm. height and about 50 cm. width.
These compartments are rammed as tightly as possible with the mixture of
caustic lime and sand, and are then closed by a cover screwed on.
The mould or box, thus filled and closed, is now placed on end in the position
shewn in Fig. 2 upon the base D of the steam chamber (the casing A having been
removed) and the other moulds are then filled and treated in the same manner,
after which the broad rings F Fig. 2 are placed round them, these being made in
two halves which are secured together by flanges and screw bolts c c.
i
As shown at Fig. 2, there remain between the rings and the sides of the moulds
spaces HH, which may be filled in with wooden or metal filling pieces which serve
to transmit the pressure exerted on the inner sides of the moulds to the rings F.
After these are fixed on, a strong plate J is placed upon the upper ends of the
moulds and is secured to the base D or to a plate placed thereon by bolts d d so as
to offer a support to the end surfaces of the moulds.
The casing A is now placed over the moulds thus tied together and is secured
steam tight to the base, and high pressure steam is admitted to the chamber and
maintained there for some days. The steam will penetrate through the crevices of
the rings F and of the moulds to the charges of the latter and will effect the
slaking of the lime which will then harden to a solid mass with the sand, forming
the artificial stone.
The steam thus operates both as the agent for slaking the lime and for exerting
considerable pressure against the outer surfaces of the moulds, in addition to the
support afforded by The rings F and bolts d which being both subject merely to a
tensile strain, are not liable to deformation.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I desire to have it understood
that I am aware that it is not novel to employ a steam chamber containing high pressure
steam in the manufacture of artificial sandstone; or to submit a mixture of slaked lime
and sand to the action of high pressure steam in a closed chamber; or to mix and mould
sand and caustic lime in a dry state, and then to allow the mixture to absorb water or
steam; or to submit a mixture of sand and lime in moulds to pressure by applying
weight thereto while subjected to the action of high pressure steam; and that I make no
claim to any such apparatus separately; or to either of such processes separately, but
that what I claim is-
An apparatus for the production of artificial stone, consisting of a closed chamber
within which moulds or boxes charged with a mixture of caustic lime and sand are
subject to high pressure steam, the moulds being so placed together that they offer

page_text: each other mutual support to withstand the bulging strain produced by the
expansion of the lime in slaking, while the strain which is transmitted to the outer-
most surfaces is effectually resisted in the one direction by circular rings and in the
other direction by stay bolts, substantially as described.
Dated thin 9th date of M 1001
ABEL & IMRAY,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION (AMENDED).
[Communicated from abroad by Dr. FRIEDRICH ZERNIKOW, of Oderberg in Mark,
Germany.]
Improved Apparatus Employed in the Manufacture of Artificial
Sandstone.
I, OLIVER IMRAY of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Fellow of the Institute of Patent Agents 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 :-
In every application of burnt pulverulent lime in the manufacture of artificial
stone, it is necessary to provide means for resisting the expansion thereof on slaking,
if it be desired to prevent any alteration in the form of the stone to be produced.
In particular this is necessary in the process in which pulverised burnt lime is
mixed dry with sand, slag powder, or other siliceous substances, then rammed into
moulds and subjected to the action of high pressure steam, so as to effectually slake
the lime; during this operation the expanding action of the slaking lime must be
effectually resisted, so that the moulds may not be burst or bulged outwards, the
lime being thus forced to penetrate thoroughly into all the interstices between the
granules of sand, so as, after hardening, to produce a perfectly hard dense cohering
mass.
According to the present invention, the requisite resistance to the expansion of
the lime is afforded by enclosing the charged moulds in a strong casing, the interior
of which is subjected to the pressure of high pressure steam which, being exerted
against the outer surfaces of the moulds, will effectually resist any bulging or
bursting action of the lime. When the moulded objects to be produced are not of
such large dimensions that a single mould fills the said casing more or less entirely,
such as large columns, it is, for the sake of economical production, desirable to
arrange the moulds for the objects that are most used, such as building blocks, slabs,
steps, cornices &c. so that they can be packed closely together within the casing, in
order that the sides that are in contact may afford each other mutual support
against the expanding action, and may consequently be made less strong than would
otherwise be necessary.
As is well known, the circular form is the only one that resists any deformation
by an expanding pressure exerted uniformly in every direction such as that
exercised by the slaking lime.
On this principle is constructed the apparatus for carrying out the said operation
as shewn on the accompanying drawings, in which Fig. 1 shews the elevation of a
vertically arranged cylindrical steam chamber A which can be raised in a vertical
position from off the base D by a winch or crane by means of the ring B at top.
To the lower end is rivetted an annular flange C by means of which it rests upon
the base D, to which it may be secured by screw bolts a a, with an intervening
packing if necessary, for forming a steam tight joint.

page_text: The steam chamber is provided with a branch pipe (not shewn in the drawings)
by which it is connected to a steam generator, as also with a water gauge and
pressure gauge. The water condensing in the chamber is led off at bottom through
a pipe b to a steam trap G from which it can be discharged from time to time.
The moulds containing the material to be treated with steam are placed within
this chamber, such moulds being arranged as shewn in plan and elevation at
Figs. 2 and 3.
The size and arrangement of the moulds may be variously modified; by way of
example, there are here shewn four main moulds of which two are, say, 50 cm. wide,
and 20 cm. high and the other two 90 cm. wide and respectively 30 cm. and 28 cm.
high, while the length is determined by the length of the chamber, which in the
present case is supposed to be 150 cm. All the main moulds or boxes are made of
galvanized or tinned sheet iron secured by screw bolts at the edges. The principal
moulds have to be so made that when placed together they can be embraced by
the rings F F Fig. 2, which may be of iron or steel.
Assuming that one of the smaller moulds be laid down flat, it will present a cubic
capacity of 150 cm. by 50 cm. by 20 cm. to be charged with the compound; if this
capacity be divided in its width by the introduction of two parallel plates running
in the direction of the length, three equal compartments will be formed of 150 cm.
length, 20 cm. height and about 50 cm. width.
These compartments are rammed as tightly as possible with the mixture of
caustic lime and sand, and are then closed by a cover screwed on.
The mould or box, thus filled and closed, is now placed on end in the position
shewn in Fig. 2 upon the base D of the steam chamber (the casing A having been
removed) and the other moulds are then filled and treated in the same manner,
after which the broad rings F Fig. 2 are placed round them, these being made in
two halves which are secured together by flanges and screw bolts c c.
As shewn at Fig. 2, there remain between the rings and the sides of the moulds
spaces H H, which may be filled in with wooden or metal filling pieces which serve
to transmit the pressure exerted on the inner sides of the moulds to the rings F.
After these are fixed on, a strong plate J is placed upon the upper ends of the
moulds and is secured to the base D or to a plate placed thereon by bolts d d so as
to offer a support to the end surfaces of the moulds.
The casing A is now placed over the moulds thus tied together and is secured
steam tight to the base, and high pressure steam is admitted to the chamber and
maintained there for some days. The steam will penetrate through the crevices of
the rings F and of the moulds to the charges of the latter and will effect the
slaking of the lime which will then harden to a solid mass with the sand, forming
the artificial stone.
The steam thus operates both as the agent for slaking the lime and for exerting
considerable pressure against the outer surfaces of the moulds, in addition to the
support-afforded by The rings F and bolts d which being both subject merely to a
tensile strain, are not liable to deformation.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I desire to have it understood
that I am aware that it is not novel to employ a steam chamber containing high pressure
steam in the manufacture of artificial sandstone; or to submit a mixture of slaked lime
and sand to the action of high pressure steam in a closed chamber; or to mix and mould
sand and caustic lime in a dry state, and then to allow the mixture to absorb water or
steam; or to submit a mixture of sand and lime in moulds to pressure by applying
weight thereto while subjected to the action of high pressure steam; and that I make no
claim to any such apparatus separately; or to either of such processes separately, but
that what I claim is :-
An apparatus for the production of artificial stone, consisting of a closed chamber
within which moulds or boxes charged with a mixture of caustic lime and sand are
subject to high pressure steam, the moulds being so placed together that they offer

page_text: each other mutual support to withstand the bulging strain produced by the
expansion of the lime in slaking, while the strain which is transmitted to the outer-
most surfaces is effectually resisted in the one direction by circular rings and in the
other direction by stay bolts, substantially as described.
Dated this 8th day of May 1891.
ABEL & IMRAI,
Agents for the Applicant.