Improvements in and relating to the Manufacture of Fire-resisting Materials.
Year: 1899

page_text: Date of Application, 16th Sept., 1899
Complete Specification Left, 29th May, 1900-Accepted, 28th July, 1900
[Communicated from abroad by ALEXANDER IMSCHENETZ
skaya, St. Petersburg, Russia, Lieutenant Colonel.
Improvements in and relating to the Manufacture of Fire-resisting
Materials.
We, THE BRITISHI URALITE COMPANY, LIMITED, of 37, Lombard Street, in the
City of London, Manufacturers, do hereby declare the nature of this invention to
be as follows:-
This invention relates to the manufacture of asbestos cardboard and like
materials and is chiefly designed to produce a stronger and more homogeneous
material than has been possible heretofore.
In the manufacture of asbestos cardboard and other similar bodies, the mixed
mass is introduced into a cardboard or paper-making machine and rolled up
onto a collecting roller in successive layers.
Now it has been discovered by our foreign correspondent that such substances
are greatly improved if colloidal silica is deposited gradatim during the building
up of the compound sheet, such deposition being produced by the reaction
described and claimed in the Specification of former Letters Patent granted to
our said correspondent, Alexander Imschenetzky, and dated 24th February 1898,
No. 4628.
To effect this, we cause a roller or rollers of wood or other material covered
with a woven or knitted tube or stocking of woollen or other material to engage
with the advancing face of the drum or cylinder on which such cardboard is
being deposited.
The said roller (or rollers) revolves in a trough supplied by suitable means
with a silicate of sodium solution of any desired strength. We prefer to use
a solution of 30 degrees Beaumé but we do not bind ourselves to that or any
other special degree of concentration.
The drum or cylinder with the cardboard thereon, rolling in contact with the
said stocking-covered roller or rollers, causes the latter to revolve in the trough
of silicate and, by contact, the sheet of cardboard, as it winds up, is thoroughly
moistened or wetted with the silicate solution.
When the cardboard drum or cylinder has revolved through a suitable angle,
we prefer 90 degrees or more, the cardboard thereon is caused to engage with a
second stocking-covered roller or rollers, the lower half of which is immersed in
a trough of a solution of sodium hydrogén carbonate (sodium bi-carbonate),
We do not however
which we prefer to be of a strength of 8 degrees Beaumé.
confine ourselves to the above mentioned or any other special concentration for
the bi-carbonate solution which we prefer to use, nor do we confine ourselves
to the use of sodium bi-carbonate as we can employ any other salt or substance
which will conveniently decompose sodium silicate with deposition of colloidal
silica.

page_text: The result of this treatment is, assuming bi-carbonate of soda to be employed,
that each component web or layer of the compound sheet is first coated with
sodium silicate and then with sodium hydrogen carbonate solutions, such coat-
ings being successive and in the order named, and such double coatings being
interposed between each web or layer of the compound sheet.
The solutions so interposed and mixed react with production of colloidal silica
between each web or layer of the compound sheet, which is thereby greatly
strengthened and improved.
atad this 16th day of Santambor 1800
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.
Improvements in and relating to the Manufacture of Fire-resisting
Materials.
We, THE BRITISH URALITE COMPANY, LIMITED, of 37, Lombard Street, in the
City of London, Manufacturers, 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 asbestos cardboard and like
materials and is chiefly designed to produce a stronger and more homogeneous
material than has been possible heretofore.
-
In the manufacture of asbestos cardboard and other similar material, the mixed
mass is introduced into a cardboard or paper-making machine and rolled up
onto a collecting cylinder or drum in successive layers.
Now our foreign correspondent has discovered that such substances are greatly
improved if colloidal silica is formed. or separated upon or in the constituent
layers of the compound sheet, during the building up of the said sheet, such
colloidal silica being produced by the reaction of a suitable decomposing solu-
tion upon a suitable silicate, such for example as the reactions, described in the
specifications of former Letters Patent granted to our said correspondent, Alexan-
der Imschenetzky, No. 5254 dated March 12th, 1895 and No. 4628 dated 24th
February 1898.
For this purpose, there are preferably employed two rollers or sets of rollers
arranged at a suitable distance apart on the periphery of the collecting-cylinder
or drum of a machine for making cardboard or paper, one of these rollers or
sets of rollers, viz., the one which first comes into contact with the sheet
of cardboard material after it has been applied to the surface of the collecting-
cylinder or drum, being adapted to transfer a solution of silicate of sodium to the
said cardboard material, and the other roller or set of rollers which afterwards
comes in contact with the said material, being adapted to apply a solution
of sodium hydrogen carbonate or other salt or substance of sodium hydrogen
carbonate or other salt or substance which will conveniently decompose sodium
silicate with decomposition of colloidal silica, on and in the said cardboard
material. The collecting-cylinder or drum is rotated at such a speed, and the two
rollers or sets of rollers are arranged at such a distance apart that each layer
of cardboard material will be first uniformly impregnated with the sodium
silicate solution, and then with the decomposing solution, before it is covered
by a fresh layer.
By these means, colloidal silica is formed or deposited on or in each of the

page_text: constituent layers of the compound sheet and thus a very strong and homogeneous
product is obtained.
In the accompanying drawing we have shown how the said invention can be
conveniently and advantageously carried into practice :-
Figure 1 is a diagrammatic sectional. elevation, showing one form of the
apparatus.
Figure 2 is a detail view, drawn to an enlarged scale, illustrating the method
of forming the cardboard sheet.
1 is the collecting-cylinder or drum on which the cardboard is deposited.
With this cylinder or drum, there engages a roller 2 of wood or other material
covered with a woven or knitted tube or stocking 3 of woollen or other material.
The roller 2 revolves in frictional contact with a roller 4 which is partly immersed
in a trough 5 supplied through the pipe 6 or by other suitable means with a
silicate of sodium solution of any desired strength. We prefer to use a solution
of 30 degrees Beaumé but we do not bind ourselves to that or any other special
degree of concentration. The roller 2, shown by way of example, is pivotally
mounted in arms 7 carried by hand-levers S one at each end of the trough.
The said hand-levers S are pivoted at 9 and can be used for moving the roller 2
into and out of contact with the drum or cylinder 1.
The cardboard material or mass 10 is supplied to the drum or cylinder 1 as a
sheet by means of a travelling web of wire-cloth or felt 11 or in any other
suitable manner.
The drum or cylinder 1 with the cardboard material deposited thereon, rolling
in contact with the stocking-covered-roller 2, causes the roller 4 to revolve in
the trough 5 and, by contact, the sheet of cardboard material, as it winds up,
is thoroughly moistened or wetted with the silicate solution.
When the collecting cylinder or drum 1 has revolved through a suitable
angle, for example, 180 degrees, the cardboard material thereon comes in contact
with a second stocking-covered roller 12. This latter roller is in frictional
contact with a similar roller 13, which makes contact with another roller 14
partly immersed in a trough 15. The rollers 12, 13, 14 are shown mounted in
arms 16 carried by hand-levers 17 one at each end of the trough said hand-
levers being pivotally mounted on the axis 18, whereby the roller 12 can be
moved so as to bring it into and out of contact with the cylinder or drum 1.
The trough 15 is supplied, through a pipe 19, or by other suitable means, with a
solution of sodium hydrogen carbonate (sodium bi-carbonate), which we prefer
to be of a strength of 8 degrees Beaumé. We do not confine ourselves to the
above-mentioned or any other special concentration for the bi-carbonate solution
which we prefer to use, nor do we confine ourselves to the use of sodium bi-
carbonate as we can employ any other salt or substance which will conveniently
decompose sodium silicate with deposition of colloidal silica.
The result of the above-described treatment is, assuming bi-carbonate of
soda to be employed, that each component layer of the compound sheet is
first coated with sodium silicate and then with sodium hydrogen carbonate
solutions, such coatings being successive and in the order named, and such double
coatings being applied to each layer of the compound sheet.
The colloidal silica formed by the reaction of the solutions from the troughs 5
and 15 on each other assists in uniting the several layers together to form a
strong and homogeneous sheet 20. When a sufficient number of layers have been
deposited on the drum 1 to produce a sheet of the desired thickness, the said
sheet is removed from the drum by dividing it along a line preferably parallel
to the axis of the said drum. It is then pressed, dried and washed.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
us by our foreign correspondent, we declare that what we claim is:-
1. The improved method of introducing silica into asbestos or other sheets,

page_text: consisting in causing the reacting liquids which form the silica to mix in
proper proportions upon the constituent layers of the sheet during the formation
thereof, substantially as described.
2. The combination, in a machine for manufacturing asbestos cardboard and
like fire-resisting materials useful for building and other purposes, of rollers
or sets of rollers, each of which is supplied with one of the reacting liquids for
forming silica, the said rollers being arranged to successively come in contact
with the cylinder or drum on which the cardboard if formed, so as to deposit the
reacting liquids in proper proportions upon the constituent layers of the card-
board in course of formation, substantially as, and for the purposes, herein before
described.
A shoot of fire-resisting material produced as above described.
8th day of May 1900.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.