Improvements in Certain Fire-resisting Materials.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
Improvements in Certain Fire-resisting Materials.
We FRANCIS MUDIE SPENCE and DAVID DICK SPENCE both of The Manchester
Alum Works, Manchester in the county of Lancaster, Manufacturing Chemists, do
hereby declare the nature of this invention to be as follows:-
This invention relates to mixtures of materials to be used for filling the hollow
jackets of fire-resisting safes, boxes, chests and chambers and the cavities of fire-
resisting doors and also the interiors of fire-resisting floors.
'
The present invention consists firstly in forming into solid compact cakes, a
mixture of sulphate of alumina or alumino-ferric or soda-alum or iron-alum or any
two or three or all of such materials with a suitable anti-tumefaction material such
as sawdust and secondly in the use of the cakes so formed for filling the hollow
jackets of fire-resisting safes, boxes, chests and chambers and the cavities of fire-
resisting doors and also in the interiors of fire-resisting floors.
We compress by means of suitable apparatus a mixture in suitable proportions
and quantities of either sulphate of alumina or alumino-ferric or soda-alum or iron-
alum or any two or three or all of such materials in a state of aqueous fusion and, a
suitable anti-tumefaction material such as sawdust and we then by suitable means
cool the hot compressed mixture and thus congeal it into solid compact cakes.
"
:
The cakes produced as above described all contain much more chemically com-.
bined water than is contained in an equal bulk of the unsolidified mixture of alum
and sawdust hitherto employed in the hollow jackets of fire-resisting safes, boxes,
chests.and chambers and in the cavities of fire-resisting doors and such cakes, may
be placed in such jackets and cavities and also in the interiors of floors.
Dated this Nineteenth day of April 1888.

page_text: Improvements in Certain Fire Resisting Materials.
We FRANCIS MUDIE SPENCE and DAVID DICK SPENCE both of The Manchester
Alum Works, Manchester in the County of Lancaster, Manufacturing Chemists,
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:
Crystallized alum it is well known contains a large proportion of chemically com-
bined water and a mixture of granulated alum, and a suitable antitumefaction material
such as saw-dust is now largely used for filling the hollow jackets of fire resisting
safes, boxes, chests and chambers, and the cavities of fire resisting doors, the mixture
being made by mixing sawdust with granulated alum.
It is
When alum alone is exposed to a high temperature it melts and boils up in
large viscid bubbles to a very greatly increased volume so that it is quite unsuit-
able to be placed alone. in the hollow jackets and door cavities. aforesaid.
accordingly mixed with a suitable anti-tumefaction material such as sawdust which
has the effect of preventing the swelling up of the alum when exposed to great heat
and thus of permitting the chemically combined water of the alum, upon which the
coolness of the contents of the safe, box, chest or chamber mainly depends, to vaporize
as tranquilly and slowly as possible.
According to the present practice the mixture of alum and sawdust is pressed
firmly into the hollow jackets of fire-resisting safes, boxes, chests and chambers and
the cavities of fire-resisting doors aforesaid but it is desirable to be able to very
greatly increase the proportion of chemically combined water in a given bulk or
volume of the fire-resisting material as that would enable either (a) the fire-resisting
power of the present jackets and door-cavities to be increased without the external
dimensions or internal capacity of the safe, box, chest or chamber being altered, or
(b) the internal dimensions of the receptacles formed in safes, boxes, chests or
chambers to be increased by lessening interiorly the jackets and door cavities without
sacrificing anything of their fire-resisting powers or (c) the external dimensions of
safes, boxes, chests or chambers to be lessened while the internal capacity and fire-
resisting power are preserved by lessening exteriorly the present jackets and door
cavities or (d) the thickness of the metal casing and thus the burglar-resisting power
of the safe, box, chest or chamber to be increased without the fire-resisting power or
the internal capacity being lessened.
The present invention relates firstly to a method of forming a mixture of sulphate
of alumina or aluminoferric or both and a suitable anti-tumefaction material, such as
sawdust and then compressing the mixture and allowing the sulphate of alumina or
aluminoferric or both to cool and congeal under pressure, the result being the pros
duction of solid compact cakes. These solid compact cakes occupy a greatly reduced
space as compared with the old mixture of granulated alum and saw-dust and their
aluminous compound is practically as efficient as alum as a source of chemically

page_text: combined water for keeping cool the contents of safes, boxes, chests or chambers
when exposed to fire. Secondly the invention relates to the use of the cakes so
formed for filling the hollow jackets of fire-resisting safes, boxes, chests and chambers
and the cavities of fire-resisting doors.
We compress by means of suitable apparatus a mixture in suitable proportions.
and quantities of either sulphate of alumina or aluminoferric or both in a state of
aqueous fusion and a suitable anti-tumefaction material such as saw-dust and we then
by suitable means cool the hot compressed mixture and thus congeal it into solid
compact cakes. We employ the sulphate of alumina or aluminoferric or both pre-
ferably in a neutral or practically neutral condition that is to say, free or practically
free from uncombined acid.
We employ the term "aluminoferric" to designate the compound or mixture now
well known amongst consumers of aluminous compounds, which consists of sulphate
of alumina combined or associated with a notable proportion of sulphate of iron.
We will now proceed to describe our mode of producing the cakes and for the
sake of practical illustration we will assume that we are about to make cakes ten inches
long, eight inches wide and two inches thick.
We employ a steam-jacketted circular pan or boiler about two feet in internal
diameter and of about two feet internal depth and internally lined with lead, the
steam-jacket of which boiler is adapted to receive steam either, at about ordinary
atmospheric pressure or at a pressure of about twenty-five or thirty pounds on the
square inch. We provide this boiler with a movable wooden lid. We also employ a
lead-lined brick tank about five feet long, four feet wide and three feet deep, provided
with about forty feet of lead pipe of about one and a half inches internal diameter
into which pipe is passed steam of a pressure of about twenty-five or thirty pounds on
the square inch.
=
We put into the boiler about two pounds and three-quarters of a pound of well
dried sawdust such as is ordinarily used by safe-makers and we spread such sawdust
over the internal heated surface of the boiler. We then cover the boiler by means of
the lid and heat the sawdust till it is hot to the touch. In the tank aforesaid we place
a small quantity of water and pass steam into the pipe, the condensed water formed
within which is ejected in the usual way. We then place a quantity of sulphate of
alumina or aluminoferric or both in the tank and evaporate the solution formed until
its boiling point rises to about 112° Centigrade. We now quickly transfer a measured
quantity equal to about six pounds in weight of the liquefied sulphate of alumina or
aluminoferric or both from the tank aforesaid by means of any suitable vessel to the
side of the steam-jacketted boiler containing the heated sawdust and having removed
the lid and caused steam of about ordinary atmospheric pressure to be passed into the
jacket we pour the said quantity of liquefied sulphate of alumina or aluminoferric or
both amongst the sawdust in the. said boiler at the same time rapidly and thoroughly
stirring the liquid and the sawdust together by means of a wooden stirrer. Wo, then
without loss of time transfer the hot nixture to a hydraulic or other suitable press
provided with apparatus such as that which we will now proceed to describe. We
employ a press the ram of which will deliver a pressure on the mould to be hereinafter
described equal to about four hundred and fifty pounds on the square inch. The
mould which we make either of strong cast iron or phosphor-bronze about five-
eighths of an inch thick is about ten inches long, eight inches wide and five inches
deep in internal measurement. The said mould is provided with a bottom and four
sides and is divided diagonally across two opposite angles into two parts or sections.
When about to receive a charge of material the two parts or sections of the mould are
brought together and held in position by two side-clamps furnished with screws.
The charge of bot material having been placed in the mould. or box and its surface
quickly smoothed over, a loose strong wrought iron or phosphor-bronze plate about
five-eighths of an inch thick and fitting easily within the mould is placed upon the
surface of the charge and the mould is then slid along guides prepared for it, till it is
directly over the ram which being then raised forces the plate placed upon the contents
of the mould against the head of the press. The sides of the mould rise around the

page_text: head of the press until the five inches or thereabouts of loose material have been
compressed to about two inches. The head of the press is provided with a, slot and
the two sides of the mould opposite to the two ends of this slot are provided with a
corresponding vertical hole or slit so that a cotter being driven through the two
sides of the mould and just over the surface of the plate placed upon the surface of the
charge in the mould, the said plate is made to retain the full or nearly the full
pressure which has been exerted on it by the ram. The ram being now lowered in
the usual way the mould is withdrawn and its contents allowed to cool, and thus to
congeal or crystallize under pressure. The clamps are then removed and the solidified
cake is released.
The cakes thus produced are dry, solid and compact and contain much more
chemically combined water than is contained in an equal bulk of the old mixture of
alum and sawdust hitherto employed and such cakes may be placed in the hollow
jackets of fire-resisting safes, boxes, chests and chambers and in the cavities of fire-
resisting doors.
After the first working stock of liquefied sulphate of alumina or aluminoferric or
both has been produced in-the tank previously mentioned we keep up the supply by
adding more of the material which is rapidly melted by the heat transmitted through
the steam-pipe. Should the boiling-point of the liquid rise above the temperature of
about 112° Centigrade we add a quantity of water sufficient to lower the boiling point
to that temperature.
It is possible to obtain a mixture of the liquefied material and sawdust by taking
an aqueous solution of it, mixing it with the requisite proportion of sawdust, and
heating, the mixture until all or practically all the water but the water present in a
sclution boiling at about 110 Centigrade has been driven off but we do not recommend
this method as it is much more difficult to evaporate the excess of water from the
mixture of liquefied material and sawdust than to produce it as we have described. *
As the iron surface of the mould is slightly acted upon by the aluminous compound
during the pressing of the cakes and a dark tint due to the formation of a film of
ferrous sulphate is given to the cakes we use in those cases where such dark tint.
would be considered objectionable; a mould made of phosphor-bronze or other suitable
metal not readily acted upon by the aluminous compound.
In the accompanying drawing, throughout which the same.letters of reference are
applied to corresponding parts, Fig. 1 is a plan and Fig. 2 a side view showing the
mould which we employ, a', a² being the parts or sections of the mould a, b, b being
the clamps employed to secure the parts or sections a¹, a² of the mould a together
when a charge of material is to be placed therein and c, c the holes or slits through
which the cotter above mentioned may be driven, and in the said drawing Fig. 3 is a
plan and Fig. 4 is a side view of the plate e placed upon the surface of the charge in
the mould a. Fig. 5 of the said drawing is a side view of the mould a showing the
position of the plate e when the charge placed in the mould a has been compressed as
above described and the cotter d has been driven through the holes or slits c-above
the plate e and the mould a has been removed from the press.
The parts or
sections a¹, a² of the mould a are provided with steady-pins or dowels and holes or
other suitable means to enable the said parts or sections a', a² to be accurately placed
together.
Fig. 6 of the said drawing shows the mould a when in the press, f being the head
of the press projecting downwards from 9 and being the slot in the head through
which slot the cotter d may be passed when being driven through the holes c c.
In order to enable the cakes to be placed in position in the hollow jackets or cavities
aforesaid we make any needful modifications in the existing parts of the said jackets
or cavities or in the order of putting them together which any fitter of ordinary skill
would readily adopt.
We also add to the jackets or cavities any new parts or, we dispense with any
existing parts in the same which the substitution of cakes for the old mixture may
render advisable. Again by means of moulds of special shape the hot mixture of
liquefied material and sawdust may be pressed into cakes of various forms as inay be

page_text: required for the various dimensions of hollow jackets or door cavities or for special
parts of them, or where it is more advantageous to do so the cakes may be cut either
by sawing or with a hatchet or other suitable tool into the special forms required to
fit or fix them in any required position. Should there be any parts in the hollow
jacket or door cavity which can not be conveniently filled up by the compressed cakes
we fill them up with a powder produced by stirring the hot mixture of liquefied
material and sawdust till its aluminous compound has.cooled and congealed.
We would have it understood that we do not confine ourselves to the above
described dimensions of apparatus nor to the above described dimensions of the cakes
produced nor to the precise proportions and quantities of materials above described
as being used.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is: :-
1. The manufacture of dry solid cakes substantially as hereinbefore described from
a mixture such as that herein before mentioned being a mixture of sulphate of
alumina or aluminoferric or the two together in a state of aqueous fusion with a
suitable anti-tumefaction material.
2. The use of the dry, solid, compact cakes such as those hereinbefore described, in
the hollow jackets of fire-resisting safes, boxes, chests and chambers and in the
cavities of fire-resisting doors, substantially as and for the purposes herein before
described.
3. The use in the requisite shapes of the solid compressed material manufactured as
hereinbefore described and shaped either by moulding or by subsequently cutting the
moulded material into the required forms.
Dated this Nineteenth day of January 1889.