IMPROVEMENTS IN THE MANUFACTURE OF GRINDSTONES AND OTHER BLOCKS OR FORMS OF ARTIFICIAL STONE
Year: 1867

page_text: LETTERS PATENT to Frederick Ransome, of Queen Street Place, Henry
Bessemer, also of Queen Street Place, both in the City of London, and
Ernest Leslie Ransome, of Greenwich, in the County of Kent, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF GRINDSTONES AND
OTHER BLOCKS OR FORMS OF ARTIFICIAL STONE."
Sealed the 8th May 1868, and dated the 11th November 1867.
PROVISIONAL SPECIFICATION left by the said Frederick Ransome,
Henry Bessemer, and Ernest Leslie Ransome at the Office of the
Commissioners of Patents, with their Petition, on the 11th November
1867.
We, FREDERICK RANSOME, of Queen's Street Place, HENRY BESSEMER,
also of Queen's Street Place, both in the City of London, and ERNEST
LESLIE RANSOME, of Greenwich, in the County of Kent, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
GRINDSTONES AND OTHER BLOCKS OR FORMS OF ARTIFICIAL STONE," to be as
follows:-
In order to manufacture grindstons of artificial stone, or it might be
blocks of artificial stone of other form, we mould the material from which

page_text: they are to. be formed in a suitable mould or chamber, which is open, at its
upper side, and has a perforated or pervious bottom at its under side, below
which is a hollow chamber connected by a pipe with an air pump, by means
of which air can be exhausted from the chamber.
The mixture of materials of which the stone is to be composed. is put into
the mould at its upper side, and the air being exhausted from the chamber
below, the materials are thereby drawn down firmly and evenly towards the
bottom of the mould; and in order to obtain a greater pressure when
required we place an impervious disc (flexible or otherwise) over the upper
surface.
When the stone is composed of a mixture of a soluble silicate of soda or
other alkali with sand, silex, or other material, which mixture has afterwards
to be treated with a solution of choloride of calcium or other solution as
described in the Specification of the Patent granted to F. Ransome, 9th
April, 1861, No. 877, we saturate the stone by applying the solution to the
upper surface of the mass whilst it is still in the mould, and drawing the
solution through the mass by exhausting the air from the hollow chamber
below it. After a suitable time water may be drawn through the stone in the
same manner to remove from it any salts which remain in a soluble state.
A current of air, either hot or cold, or even artificially deprived of its.
moisture may then be drawn through the stone in the mould for the purpose.
of displacing the moisture and drying the stone.
In order the more readily to apply the principle of exhausting air in the
manufacture of artificial stone to such articles as do not present too plain or
flat surfaces of large extent, we mould them hollow or on a hollow perforated
or pervious core, or we insert one or more perforated tubes in the mould
when the article is being moulded, or we mould the article solid, and then
bore a recess or cavity therein; in either case the article is placed with the
apperture in connection with an air pump, so that chloride of calcium or
other fluids may be drawn through it, as before described.
Pipes, columns, and other articles of a circular figure may be formed
in hollow pervious cores or on revolving surfaces, the hollow axes of which
are in connection with an air pump; the materials adhering to their exterior
surfaces by atmospheric pressure may be moulded or "struck up "by a proper
scraper in a manner well understood.
Our Invention also consists in rendering such pipes or other articles, water-
proof or impervious by drawing into the pores thereof by atmospheric pressure
asphalte and bituminous and other matters capable of rendering them imper-
vious, and improving the quality of the stone.

page_text: Our improvements also relate to the manufacture of tiles or slabs of.
artificial stone having designs or patterns formed of a different color to tho.
general body of the stone. For this purpose we make a pierced or perforated.
wood or metal pattern, which is laid on to a flat pervious surface, the
colored pulverised matters, such as titaniferous iron sand, or the colored
sands of Alumn Bay, or crushed ores, or metallic slags, or burned colored clay
mixed with a fluid selicate are then put into the perforations of the pattern
and drawn down firmly to the pervious surface by exhausting the air from
beneath it; the pattern is then lifted, and the moulded design will remain in
relief upon the pervious surface. The materials intended to form the body of
the slab or tile are then put on and occupy the space left by the removal of
the perforated pattern; this material is added until a sufficient thickness is.
obtained, and the compound mass is then treated in the same manner as
herein-before described in reference to the making of artificial stone by the
passage of fluids through them by atmospheric pressure.
We also in some cases form grindstones of artificial stone, with hollow-
metal bushes or hollow or solid axes. These bushes or axes may have one or
more flanges or discs, or projections formed thereon, or may have radial
arms attached thereto, and be embedded in the stone at the time of moulding
the same. These bushes or axes if of iron may be galvanised or otherwise
coated to prevent oxidation.
When forming grindstons of large dimensions we, in some cases, employ
for the central part a cast-iron wheel of somewhat less diameter than the
stone to be formed, and around the circumference of this wheel we mould a
ring of artificial stone; the ring of artificial stone is held between side flanges
around the circumference of the wheel.
In some cases also to prevent the breaking up of grindstones we imbede in
the stone one or more concentric rings or hoops of iron or other metal. Per-
forations may be formed through each ring, which when the stone is mounted
or filled up with the materials of which the stone is to be formed, and thus
the parts of the stone on the opposite sides of the ring are united together.
In some cases it may be found preferable to form the central portion of the
grindstone in such a manner that metal hoops may be mounted or afterwards.
affixed thereon externally. In order to give to grindstones a sharp cut we in
some cases use crushed or broken silex or flint divided by sieves into different
degrees of fineness; and also where great hardness is required we employ
tetaniferous iron sand alone or mixed with other materials..
We also desire it to be understood that although we prefer to apply the
exhaust to the bottom of the mould, as above. described, it might be found.

page_text: convenient to apply the exhaust to other parts of the mould. In place also
of forming a partial vacuum for the purposes herein-before described, the
same general effects may be obtained by using a pressure in excess of the
atmosphere, either alone or in combination with the exhaust.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick Rausome, Henry Bessemer, and Ernest Leslie
Ransome in the Great Seal Patent Office on the 11th May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, FREDERICK
RANSOME, of Queen Street Place, HENRY BESSEMER, also of Queen Street
Place, both in the City of London, and ERNEST LESLIE RANSOME; of
Greenwich, in the County of Kent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of November, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
ns, the said Frederick Ransome, Henry Bessemer, and Ernest Leslie
Ransome, Her special licence that we, the said Frederick Ransome, Henry
Bessemer, and Ernest Leslie Ransome, our executors, administrators, and
assigns, or such others as we, the said Frederick Ransome, Henry Bessemer,
and Ernest Leslie Ransome, 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
"IMPROVEMENTS IN THE MANUFACTURE OF GRINDSTONES AND OTHER BLOCKS OR
FORMS OF ARTIFICIAL STONE," upon the condition (amongst others) that we,
the said Frederick Ransome, Henry Bessemer, and Ernest Leslie Ransome,
our executors or administrators, by an instrument in writing under our, or
their bands and seals, or under the hand and seal of one of us or them,
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 I, the said
myself and the said Henry Bessemer and
Frederick Ransome, on behalf of
Ernest Leslie Ransome, do hereby
declare the nature of the said Invention, and in what manner the same is to he

page_text: performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in the manufacture of
grindstones and other blocks or forms of artificial stone.
In order to manufacture grindstones of artificial stone, or it might be blocks
of artificial stone of other form, we mould the material from which they are to
be formed in a suitable mould or chamber which is open at its upper side and
has a perforated or pervious bottom at its under side, below which is a hollow
chamber connected by a pipe with an air pump by means of which air can be
exhausted from the chamber. The mixture of materials of which the stone is
to be composed is put into the mould at its upper side and the air being
exhausted from the chamber below, the materials are thereby drawn down
firmly and evenly towards the bottom of the mould, and in order to obtain a
greater pressure when required we place an impervious disc (flexible or
otherwise) over the upper surface. When the stone is composed of a mixture
of soluble silicate of soda or other alkali with sand, silex, or other material
which mixture has afterwards to be treated with a solution of chloride of
calcium or other solution as described in the Specification of the Patent
granted to one of us, namely, the said Frederick Ransome, dated the 9th April
1861 (No. 877); we saturate the stone by applying the solution to the upper
surface of the mass whilst it is still in the mould and drawing the solution
through the mass by exhausting the air from the hollow chamber below it.
We then prefer to take the block of stone out of the mould and immerse it in
a solution of chloride of calcium the temperature of which is gradually raised
to or near a boiling point in which the stone should remain a sufficient length
of time to produce a uniform temperature throughout the mass of the stone.
Or in place of this a hot or boiling solution of chloride of calcium may be
drawn through the stone whilst it is in the mould. Afterwards water may be
drawn through the stone in the same manner to remove from it any salts
which remain in a soluble state. If the stone has not been removed from the
mould water may be drawn through it in the same manner as the solutions
were previously drawn down, but if the stone has been removed from the
mould in order that the stone may be immersed in a boiling solution of the
chloride of calcium then the stone may be placed in a suitable casing so that
a vacuum may be formed below its under surface whilst its upper surface may
be covered with water. A current of air either hot or cold or even artificially
deprived of its moisture may afterwards be drawn through the stone for the
purpose of displacing the moisture and drying the stone.
In order that the mode by which we practically carry into operation the

page_text: manufacture of grindstones may be clearly understood we have shown at
Figure 1 on the Sheet of Drawings annexed a vertical section of a mould such
as we prefer to employ.
Figure 1 a, a, is a hoop or ring of iron resting on a eircular plate 6 and
having a false bottom or moveable plate c of the same dimensions as the
internal diameter of the hoop or ring, which circular plate c is perforated with
numerous small holes equally distributed over its surface, and is made to rest
on frames or blocks of varying dimensions so as to alter the position of the
perforated plate to suit the required thickness of the stone when moulded.
A cloth or other pervious fabric may be laid over the perforated plate when
desired. A pipe e leads to an exhaust chamber which is connected with an air
pump or other exhaust apparatus capable of exhausting or drawing off the air
or any watery solution that may pass through the perforations into the box-b.
The sand and silicate of soda or other material to be moulded is first mixed
intimately together in the usual way, and is. then put gradually into the hoop a,
meanwhile the exhaust apparatus is put in operation which will remove the
air from the box-and cause the external atmosphere to press upon the loose
materials occupying the hoop er mould a, the materials are added until the
hoop a is filled or rather heaped up when a thin disc of india-rabber, elastic
cloth, or other soft impervious material is laid on over the entire surface of the
moulded article, the passage of the external air through the porous material
will thus be prevented, and the whole weight of the atmosphere or nearly so
will press the materials firmly down-into the mould, or if it be desired to employ
a greater pressure on the upper surface of the materials in the mould a lid or
cover may be fixed over the top of the mould, the edges of the disc of
vulcanized india-rubber being then held between a flange on the top of the
mould and a flange on the cover as shown at Figure 2. Air or other fluid
may then be forced on to the top of the flexible disc marked d at the same
time that air is exhausted from the bottom of the mould; or in place of
drawing the solutions through the block of material in the mould by means of
an exhaust the solutions may be forced through by pressure in combination
with the exhaust, or by pressure only. The cover and elastic disc may after-
wards be removed, and any superfluous material rising above the upper edge of
hoop a may be removed by passing a "striker" or straight edge across the
top of the hoop and thus bevelling it down, a band or hoop of india-rubber f
is then put around the hoop a, as shewn in Figure 3, and a jacketted pipe g
is moved over the mould, and by opening a cock h a solution of chloride of
calcium is allowed to flow all over the upper surface of the moulded article
and is prevented from flowing off from it by the india-rubber band f. It will be

page_text: observed that the nozzle of the cock h becomes immersed in the fluid before
the fluid reaches as high as the upper surface of the india-rubber ring, by
which means the fluid is prevented from flowing over in consequence of the
pipe g being in connection with a closed vessel, as is well understood. The
action of the exhaust pump will cause the fluid chloride of calcium to permeate
the moulded mass and rapidly and uniformly convert the moulded materials into
stone. When a sufficient quantity of the chloride of calcium has been passed
through the stone the cock h is closed, the exhaust being still kept up.
In order the more readily to apply the principle of exhausting air in the
manufacture of artificial stone to such articles as do not present two plain or
flat surfaces of large extent, we mould them hollow or on a hollow perforated
or pervious core, or we insert one or more perforated tubes in the mould when
the article is being moulded, or we mould the article solid and then bore a
recess or cavity therein. In either case the article is placed with the aperture
in connection with an air pump so that chloride of calcium or other fluids
may be drawn through it as before described, or the article may be placed
in a closed case containing the chloride of calcium or other fluid, the ends
of the perforated tubes being open to the atmosphere pressure may then be
applied to the fluid in the closed case and the fluid will thereby be forced
through the article.
Pipes, columns, and other articles of a circular figure may be formed on
hollow pervious revolving cores, or on revolving surfaces, the hollow axes
of which are in connection with an air pump, the materials when fed on
to such revolving surfaces will adhere thereto by atmospheric pressure and
"struck up
may be moulded or
by a proper scraper in a manner well
understood.
"
Our Invention also consists in rendering such pipes or other articles water-
proof or impervious by drawing into the pores thereof by atmospheric pressure
asphalt and bituminous and other matters capable of rendering them impervious
and improving the quality of the stone. For this purpose the asphalt, pitch,
or other matter to be used for saturating the stone must be rendered fluid
either by means of a suitable solvent or by heat when of a nature to render
heat necessary for its fluidity and the article to be saturated should be immersed
therein and its hollow interior be made to communicate with the exhaust
apparatus so as to draw the fluid matter into the pores of the stone when heat
is required to render the saturating matter fluid. We prefer to beat the
articles to be saturated to about the same temperature as the fluid before
immersing them therein.
Our improvements also relate to the manufacture of tiles or slabs of artificial

page_text: stone having designs or patterns formed of a different color to the general
body of the stone. For this purpose we make a pierced or perforated wood
or metal pattern which is laid on to a flat pervious surface the colored
pulverized matter, such as titaniferous iron sand, or the colored sands of Alum
Bay, or crushed ores, or metallic slags, or burned colored clay mixed with a
fluid silicate are then put into the perforations of the pattern and drawn down
firmly to the pervious surface by exhausting the air from beneath it, the
pattern is then lifted and the moulded design will remain in relief upon the
pervious surface; the materials intended to form the body of the slab or tile
are then put on and occupy the space left by the removal of the perforated
pattern, this material is added until a sufficient thickness is obtained and the
compound mass is then treated in the same manner as herein-before described
in reference to the making of artificial stone by the passage of fluids through
them by atmospheric pressure.
We also in some cases form grindstones of artificial stone with hollow
metal bushes or hollow or solid axes. These bushes or axes may have one or
more flanches or discs or projections formed thereon, or may have radial arms
attached thereto and be embedded in the stone at the time of moulding the
same. These bushes or axes if of iron may be galvanized or otherwise coated
to prevent oxidation. An example of one form of hollow bush is shewn at
Figure 4 which is a section through a grindstone in which such bush has been
embedded P is the bush with a square hole 9 through it; around the central
part of the bush is a perforated flange p¹ for the purpose of securing the bush
firmly in the stone.
Figure 5 is a side elevation of the stone shewing the perforated flange in
dots. A solid axis r may be embedded in grindstones of a smaller size
having a plain central disc ¹, as shown in section in Figure 6. When
forming grindstones of large dimensions we in some cases employ for
the central part a cast-iron wheel of somewhat less diameter than the stone to
be formed, and around the circumference of this wheel we mould a ring of
artificial stone; the ring of artificial stone is held between side flanges around
the circumference of the wheel. This mode of making grindstones is shewn in
section in Figure 7, and in elevation in Figure 8, where shews a cast-iron
wheel or boss having a deep flanged groove at undercut or dovetailed
so as to firmly retain the stone moulded therein; t shews the stone which
may be used until it is worn down as far as the iron flanges, after which
the dovetailed groove may be cleared out and a new stone moulded therein.
In some cases also to prevent the breaking up of grindstones, we embed in
the stone one or more concentric rings or hoops of iron or other metal,

page_text: perforations may be formed through each ring which when the stone is
moulded are filled up with the materials of which the stone is to be formed,
and thus the parts of the stone on the opposite sides of the ring are united
together.
In some cases it may be found desirable to form the central portion of the
grindstone with a boss projecting from each side of it so that metal hoops
may be moulded or afterwards affixed thereon externally. In order to give
to grindstones made from artificial stone a sharp cut we in some cases use
crushed or broken silex or flint in place of sand in the manufacture of such
stones. For this purpose the silex or flint after being reduced to powder
by a suitable stone crusher, such for example as those known as Blake's stone
crushers, is divided by sieves into different degrees of fineness to be separately
used for making either coarse or fine stones, also when grindstones of great
hardness are required we similarly employ titaniferous iron sand alone or
mixed with other materials.
We also desire it to be understood that although we prefer to apply the
exhaust to the bottom of the mould as above described, it might be found
convenient to apply the exhaust to other parts of the mould; in place also of
forming a partial vacuum for the purposes herein-before described the same
general effects may be obtained by using a pressure in excess of the atmosphere,
either alone or in combination with the exhaust.
Having thus described the nature of our said improvements, and the manner
in which the same may be carried into practical operation, we desire it to be
understood that we do not confine ourselves to the precise details herein
specified, provided that the general character of our said improvements are
retained; but what we claim to be new and desire to secure by the said in
part recited Letters Patent is as follows:-
Firstly. We claim in the manufacture of grindstones and other blocks or
moulded pieces of artificial or concrete stone the moulding or compressing the
materials of which such grindstones, blocks, or moulded pieces of artificial or
concrete stone are composed by means of a vacuum or partial vacuum, or by
pressure, or by both vacuum and pressure combined, susbstantially in the
manner herein described.
Secondly. The saturating, washing, and drying blocks or moulded pieces of
artificial stone by means of a vacuum or by pressure, or by both vacuum and
pressure combined, substantially in the manner herein described.
Thirdly. We claim in moulding articles in artificial or concrete stone, the
employment of perforated tubes and hollow or pervious cores for the purpose

page_text: of facilitating the saturation, washing, or drying of such articles by the
employment of exhaust apparatus or by pressure.
Fourthly. We claim moulding. artificial or concrete. stone- on. hollow or
pervious revolving cores, the requisite pattern or configuration being "struck
up" by the employment of suitable scrapers, the material being caused to
adhere to and be retained on such revolving core by external atmospheric
pressure operating in consequence of the exhausting of such hollow core.
Fifthly. We claim rendering waterproof or impervious pipes or other
articles moulded in artificial or concrete stone by drawing into the pores
thereof by means of a partial vacuum, in the manner herein described, fluid
asphalt and bituminous or other matters capable of improving the quality of
the stone.
Sixthly. We claim making tiles or slabs of artificial or concrete stone having
designs or patterns formed of different colored materials in the manner
herein-before described.
Seventhly. We claim in the manufacture of grindstones. embedding an iron
bush or axis in the material and also embedding hoops therein in the manner
and for the purposes described.
Eighthly. We claim moulding the material known as Ransome's concrete
stone around the circumference of an iron wheel having suitable flanges for
retaining the same as herein described.
Ninthly. We claim employing crushed flints in lieu of sand in the manu-
facture of grindstones of artificial or concrete stone as herein described.
Lastly. We claim the employment of titaniferous iron sand alone or
mixed with common silicious sand in the manufacture of grindstones as herein
described.
In witness whereof, I, the said Frederick Ransome, have hereunto set
my hand and seal, this Eleventh day of May, in the year of our Lord
One thousand eight hundred and sixty-eight.
FRED". RANSOME. (L.S.)