Year: 1888

page_text: Date of Application, 26th Mar., 1888
Complete Specification Left, 27th Dec., 1888
Complete Specification Accepted, 5th Feb., 1889
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 :-
Crystallized alum it is well known, contains a large proportion of chemically combined
water and a mixture of granulated alum and a suitable anti-tumefaction material such
as sawdust 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 present inven-
tion consists firstly, in a method of forming a mixture of alum and a suitable anti-
tumefaction material such as sawdust into solid compact cakes which solid compact
cakes occupy a greatly reduced space 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 alum 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. We employ either ammonia-alum or potash-
alum or a mixture of ammonia-alum and potash-alum.
The cakes produced as above described contain much more chemically combined
water than is contained in an equal bulk of the unsolidified mixture of alum and saw-
dust hitherto employed and such cakes may be placed in the hollow jackets of fire-
resisting safes, boxes, chests and chambers, in the cavities of fire-resisting doors and
in the interiors of floors.
It is obvious that in the case of fire-resisting safes, boxes, chests and chambers
the space gained in the cavities of the jacket by the employment of the solid
compact cakes in place of the unsolidified mixture may either be filled up with
cakes to greatly increase the fire-resisting power of the safe, box, chest or chamber or
it may be taken from the cavities and added to the interior of the safe, box, chest or
chamber to increase its cubic capacity. A similar advantage is obtainable by the use
of the cakes in the case of fire-resisting doors.
Dated this Trant foumih
1000

page_text: COMPLETE 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 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 combined
water and a mixture of granulated alum and a suitable anti-tumefaction material such
as sawdust 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.
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 unsuitable to be
placed alone in the hollow jackets and door cavities aforesaid.
It is 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 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, again the internal dimensions
of the receptacles formed in safes, boxes, chests or chambers may be increased by
lessening interiorly the jackets and door cavities which with our improved mixture
may be done without sacrificing anything of their fire-resisting powers, again the
external dimensions of safes, boxes, chests or chambers may be lessened while the
internal capacity and fire-resisting power are preserved, by lessening exteriorly the
present jackets and door cavities, or again, the thickness of the metal casing and thus
the burglar-resisting power of the safe, box, chest or chamber, may 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 alum and a
suitable anti-tumefaction material such as sawdust and then compressing the mixture
and allowing the alum to cool and congeal under pressure the result being the produc
tion of solid compact cakes. These solid compact cakes occupy a comparatively
greatly reduced space. Secondly, the invention relates to the use of the cakes
formed for filling the hollow jackets of fire-resisting safes, boxes, chests and chamber
and the cavities of fire-resisting doors.
5

page_text: We compress by means of suitable apparatus a mixture in suitable proportions and
quantities of alum 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. We employ either ammonia-alum or potash-
alum or a mixture of ammonia-alum and potash-alum.
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 steami 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 safemakers 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 alum in the
tank and evaporate the solution formed until its boiling point rises to about 106°
Centigrade this being the temperature at which the alum is about at the state of
aqueous fusion and in which state there is practically no water in the liquid but the
water of crystallization. We now quickly transfer a measured quantity equal to about
six pounds in weight of the liquefied alum 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 alum amongst the
sawdust in the said boiler at the same time rapidly and thoroughly stirring the
liquefied alum and the sawdust together by means of a wooden stirrer-We then
without loss of time transfer the hot mixture of alum and sawdust 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 rain 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 hot 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 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

page_text: of the plate placed upon the surface of the charge of alum and sawdust in the mould
the said plate is made to retain the full or nearly the full pressure which has been
exerted on the charge of alum and sawdust 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 unsolidified
inixture 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 alum has been produced in the tank
previously mentioned, we keep up the supply by adding more alum crystals which are
rapidly melted by the heat transmitted through the steam pipe. Should the boiling
point of the liquefied alum rise above the temperature of about 106° Centigrade we
add a quantity of water sufficient to lower the boiling point to that temperature.
It is possible to obtain a mixture of alum in a state of aqueous fusion and
sawdust by taking an aqueous solution of alum, mixing it with the requisite pro-
portion of sawdust and heating the mixture until all or practically all the water
but the water of crystallization 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 alum and sawdust than to produce the alum in a state of aqueous fusion
by itself.
It is possible to produce a cake of alum and sawdust by mixing a hot liquid
containing alum partly in the state of aqueous fusion and partly in the state of
aqueous solution with the requisite proportion of sawdust and compressing the mixture
in a manner similar to that above described but as such a cake would contain throughout
its mass water over and above the water of crystallization which water if allowed to
remain in the cake would cause corrosion of the ironwork of the jacket or door cavity
in which such cake was placed, and it would therefore be necessary for such water
to be carefully "dried off," before the cake was placed in the safe, box, chest or
chamber or in the cavity of a fire-resisting door we do not recommend this process.
As the iron surface of the mould is slightly acted upon by the alum 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 alum.
:
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 a² 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 quantity of alum and sawdust 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 quantity of
alum and sawdust placed in the mould a has been compressed as above described and
the cotter d has been driven through the holes or slits c c above the plate e and the
mould a has been removed from the press-The parts or sections at, 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 a³, a² to be accurately placed together.
+
Fig. 6 of the said drawing shows the mould a when in the press, being the
head of the press projecting downwards from 9 and being the slot in the head f
through which slot h 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

page_text: 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 alum and sawdust may be pressed into cakes of various forms as may be
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 cannot be conveniently filled up by the compressed cakes
we fill them up with a powder produced by stirring the hot mixture of liquefied alum
and sawdust till its alum 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 ammonia-alum
or potash-alum 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 hereinbefore
described.
3. The use in the requisite shapes of the solid compressed material manufactured
as herein-before described and shaped either by moulding or by subsequently cutting
the moulded material into the required forms.
Doted this Taxanty-fourth day of December 1888