Improvements in the Manufacture of Igniferous Fuses, applicable for Blasting and other Purposes.
Year: 1894

page_text: Date of Application, 24th Dec., 1894
Complete Specification Left, 24th Sept., 1895-Accepted, 2nd Nov., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Igniferous Fuses, applicable
for Blasting and other Purposes.
I JAMES WATSON, of 2 Whitehall Court, London, S.W., in the County of
London, Gentleınan do hereby declare the naturo of this invontion to be as
follons:-
This invention relates to igniferous fuses for mining purposes, being such as to
convey fire to blasting charges in a safe manner and at a regular speed, which
cannot explode nor enter into combustion of themselves, nor become a source of
danger in any way at any time or under any circumstances.
The Bickford fuse is the most generally known and accepted type of such fuses
but it requires special arrangement and care to enable it to be used under water.
Many attempts liave been made at various times to substitute for the core of
mealed gunpowder of the Bickford fuse some other fire carrying material, suited to
the various requirements of mining and not liable to interruptions which might
pass unnoticed during the process of spinning the covering of the complete fuse
around the core.
Of these attempts the most nearly successful have been those made with carefully
prepared gun cotton yarns steeped in bichromate of potassium. But the inherent
lability to decomposition of all gun-cotton in a dry state, has rendered their
preservation during storage for any length of time uncertain and has interfered
with the general adoption of fuses so prepared.
During late years chemical compounds made with nitroglycerine and gun-cotton,
with or without the addition of special solvents and with oxydisers to render
combustion more active, have been patented, the resulting compound being squeezed
out under pressure through a moulding die so as to give a plastic celluloidal cord
having a diameter of from half a millimeter to two millimeters, the smaller diameter
being, generally speaking, recommended where the plastic mixture has been more
powerfully oxydised, and the large diameter adopted where the oxydising was less
complete.
It has been recognized that the early attempts made to produce a fuse core in
this manner resulted in a fuse too sensitive to concussion for practical use, especially
in the case of the more highly oxydised types, they having also a tendency to throw
out while barning bright sparks or flames from their outer surfaces.
Any breaking or interuption of these fuse cores was not easy to repair
promptly and neatly, during the process of covering them with a textile or other
external covering, if the fuse cores were covered. The fuse core might however
be used in the open air bare without any external covering.
In this condition any breakage would be at once perceived by the miner, and
the broken ends could be roughly tied together by hum. It was also claimed that
no smoke would be given off in buining by avoiding the use of tarring or otherwise
coating the outer surface of the textile coating and that no rapid deterioration in
water would take place.
But any package containing such fuse cores only covered with a textile conting
might ignite in bulk, if any portion of it ignited, and each strip or length of some

page_text: of such fuses were very liable to the effects of concussion, if struck by a tamping
tool while being used.
More recent attempts to solve the problem ely for their success on employment
of highly nitrated hydrocarbons incorporated with nitroglycerine before gun-cotton
or nitio cellulose is added, the mixture being after waids further oxydised by
adding some highly oxydised compounds less sensitive to concussion.
This uewly modified igniferous fuse core without any incombustible external
covering remains liable, if packed for sale or delivery, to occasion serious incon-
venience and eveu dauger, more especially in case of any fire or explosion taking
place in its immediate vicinity from whatever cause such fire or explosiou should
occur, and even supposing that the outbreak of such fire or explosion were in not
way attributable to the package of igniferous fuse core, nor to its contents. And
when it is desired to add a textile or other covering it is not more easy than before
to repair any breakage or interruption of the core during the process of weaving
or applying such covering, no even to detect such interruption in the case of a very
small core half a millimeter in diameter.
Nevertheless an interruption in the igniferous fuse core is always liable to entail
the extinction of the fuse before the fire reaches the charge.
If a fuse core of two millimeters in diameter were used, any interruption would
be more easily detected, but the repairing of it during the process of applying a
textile or other covoring would not be much easier, whilst the tendency to
throw out flames from its outer surface would be greater and the cost of material
in such a fuse core would be sixteen times greater than in the case of a core only
half a millimeter in diameter, similarly composed.
To obviate the aforesaid defects and at the same time to obtain a reliable and
cheap safety fuse of the aforesaid type, the improvements I have made are as
follows:-
My invention is designed to obviate effects of concussion by forming the
igniferous fuse coro over and around an interior cushion of textile matter or
otherwise, in addition to the outer covering. The invention is further intended
for the longitudinal tensile strengthening of the fuse core so that parting of the
core during the application of an outer cover, or during its employment or handling
when in use or otherwise may be avoided. The invention also has the effect that
the liability of the fuse core to throw out sparks or flaines through its outer cover
during its combustion will to a great extent disappear owing to the attenuation of
the igniferous matter.
This invention may be carried out by cushioning the core between two soft
surfaces of textile matter by placing in the centre of the fuse core a thread or
threads, single or twisted together around which the plastic material forming the
core will be smeared, squeezed or laid on, the thread or threads being drawn
through the plastic material in a vessel where it is subjected to pressure to squeeze
it through a suitable outlet aud in such manner that the thi cad or threads shall
issue forth from this outlet in the heart of the fuse core.
Such cential thread or cord may be, in the first instance, oxydised by being
steeped in a solution of bichromate of potassium or other suitable bath and then
dried before being drawn down through the plastic material.
My invention is applicable to any fuse core material which 18 or can be made
of a plastic nature and I purpose using the plastic material of the best and most
suitable kind.
I can use an igniferous compound made as follows-In 38 parts by weight of
mitroglycerine, dissolve 30 parts of nitro cellulose, either by the application of
heat, up to 50 degrees Centigrade, kneading carefully, or by the addition of some
of the known volatile solvents, such as acetate of ethyle, and carefully mix with
the same 30 parts of very finely powdered bichromate of potassium, addig 2 parts
of vaseline to complete the compound and kneading the whole until intimately
mixed, adding, where desired, for the purpose of obtaining greater plasticity,
from 2 to 4 per cent. of gum tragacanth, which 18 first dissolved in spirits of wing

page_text: and then incorporated by a careful grinding or kneading together with the
aforesaid igniferous compound. By using it in an annular sheet as it would be
when spread around a central thread or cord, the liability to throw out sparks or
flames through its outer coverings will, to a great extent, disappear.
The central thread or cord will give security against any bieaking and paiting
of the igniferous fuse core so prepared. Threads of any suitable material may be
used. I may also modify the shape of the moulding die or outlet of the pressure
chamber so as to give to the issuing fuse core not only a plain cylindrical surface
of a predetermined diameter, but also, when desired, a corrugated oi ribbed form,
and may so twist the core as it issues from the pressure chamber as to give, when-
ever desirable, a twisted form to the issuing fuse, which would thus resemble a
screw threaded cylinder, the threads of such scrow being more or less prominent,
the object being to retain between the screw threads a certain amount of
atmospheric air, both in reason of its cushioning properties and to assist the
combustion of the fuse core where desirable, this latter object being further
assisted when desired by the oxydising of the central thead or cold, or by making
screw threads, ribs or corrugations also on the inner surface of the annular
igniferous fuse core, next to the central thread or cord Nevertheless, when
desired, the plastic material may be drawn out through a circulai die in an even
sheet around the central cord or thread, it may even be possible to dispense
with pressure, or to use only slight pressure in the chamber or receptacle
containing the plastic material which is to be drawn out from it in the form of a
fuse core.
Additional cushioning should in every case be supplied in the shape of external
coverings, beginning with textile yarns applied in spiral forms as in Bickford fuse,
with one or more external tapes added, where desued, and an incombustible
vainish prepared with kaolin, ochre or other similar earthy or minoral matter
mixed with glue etc on the outside. Or I can make the inner cushioning of the
annular fuse core material consist entirely of atmospheric air, by drawing out
the plastic material from the pressure chamber through a suitable moulded die,
so as to give a hollow centre to the fuse core, which will thus take a tubular
form
The tubes so formed may have smooth surfaces or they may be made corrugated,
ribbed or screw-threaded internally or externally, or both, the ubs giving a better.
resistance to external pressure. And in the annular substance of such tubes I can,
draw out through the pressure chamber a sufficient number of fine strong threads,
or one such thread, oxydised or not, to give tensile strength to the tube, and
prevent any breaking oi snapping of it.
A thead sincared or covered with an igniferous compound of the nature of that,
described here, may be placed with advantage in the powder centre of ordinary
Bickford fuse whereby, in case of any interruption in the powder core, the smeared,
thread will carry a spark of hire through the empty pait until it reaches the next
grains of powdei, and a miss fire will thus be avoided.
By the improvements hereindescribed 1 obtain great security against any
effects of concussion, also against any breaking or interuption in the fuse cole,
and, by using a diminished quantity of the plastic material, great relative
cheapness of manufacture is attamed
Dated this 24th day of December 1894
HIERBERT HADDAN & Co.,
Agents to the Applicant.

page_text: Improvements in the Manufacture of Igniferous Fuses, applicable for
Blasting and other Purposes.
I, JAMES WATSON of 2 Whitehall Court, London SW, in the County of
London, Gentleman do hereby declare the nature of this invention and in what
manner the same is to bo performed to be particularly described and ascertained in
and by the following statement :-
This invention has for its object improvements in that class of safety fuses which
are made from a plastic mass containing nitrocellulose and nitroglycerine, with or
without the addition of oxydızers.
Such plastic mass, will in the following Specification be termed, for want of a
better word "celluloidal fuse core."
A inain object of this invention is to diminish the sensitiveness to concussion
of such fuse corez, by certain mechanical mangements herein described,
independently of any chemical improvements in the composition of the celluloidal
fuse core.
These mechanical arrangements are directed to the cushioning of celluloidal fuse
cores; preferably by atmospheric au 10 channels contrived for the purpose and
placed internally or externally, or both; but in certain cases, by textile threads
or wadding; or by a combination of textile surroundings or cential paddings with
air channels.
A subsidiary but highly important advantage of this invention is that with the
fuse hereinafter described I secure a rate of combustion more nearly approaching
that to which miners have hitherto been accustomed when using the ordinary
safety fuse, known as Bickford fuse,-than is commonly obtainable with celluloidal
fuse cores whose unaided rate of combustion is much slower.
Where textile threads are employed, more especially in the heart of the
celluloidal fuse core, they may be of such nature as to add to the tensile strength
of the fuse core.
An efficient celluloidal fuse core is prepared as follows
8 parts, by weight, of bichromate of potash, are dissolved in a sufficient quantity
of very warm water; and 30 paits by weight of soluble (di-nitrated) gun-cotton,-
or preferably when it can conveniently be procured, of insoluble (ti-nitiated)
gun-cotton, are placed in the solution before it has cooled or begun to deposit
any of the bichromate of potash.
The gun cotton absorbing the whole of the solution is thus dyed of a yellow
colour; it should then be dried under a gentle heat.
A sufficient quantity of acetone or similar volatile solvent is added to the gun
cotton which is then mixed with nitroglycerine, thoroughly pure, not less than
38 parts nor more than 47 parts, by weight.
If dinitrated gun-cotton 18 used a smaller quantity of acetone or similar volatile
solvent will suffice than if trimtiated gun cotton is used, because a part of the
dimitrated gun cotton can be dissolved by the niti ogly cerine during the mixing or
kneading that is to follow.
Whether the gun cotton used be dintrated or initiated, it is important
that it is of the purest and best quality, absolutely exempt from any trace of free
acid.
A kneading-machine (such as those known as Weiner & Pfleiderer's) should be
used for mixing the aforesaid ingredients. The kneading must be continued until
the mass 18 thoroughly mixed into a homogeneous paste.
The resulting paste is at once placed in an irou cylinder under hydraulic oi air

page_text: pressure so that it may be squeezed out through suitable dies fixed to the base of
the cylinder into cords of the desued shapes.
These cords on issuing from the pressure cylinder are rolled upon suitable swifts
or recls, which are placed in a gently heated chamber until the acetone or other
volatile solvent is completely evaporated.
The celluloidal fuse coie is then ready to be covered with its outer textile
covering which in all cases where the fuse has to be carried about, or placed in
the hands of ordinary mineis, is a necessary adjunct.
The form of the dies to be fixed in the pressure cylinder of great importance.
They may be made with a central pin so as to leave a hollow central air space in
the fuse core, the inner circumference of the outer part of the die may be smooth,
or it may have fiue longitudinal grooves sunk in it, to give a series of longitudinal
11bs on the outer surface of the fuse core.
O the die may be made of such form that the fuse core shall issue in a kind
of crescent or hoise shoe section, or any desned form may be given to the fuse core
so as to ensure that when a textile covering has been spun around it, an air channel
or channels, will be covered in within or around and iù direct communication with
the celluloidal fuse core.
When the fuse core is tubular or of a horse shoe shape one air channel will
exist in or near the centre; when the outer surface is ribbed or grooved, air
channels will exist between the ribs; or if the section be triangular or square or
polygonal with deeply hollowed sides, or if a star shaped section be employed, an
channels will exist between the projecting parts of any of these various forms.
When it is desued to have a textile cushion in the heart or centre of the fuчo
core such cushion may consist of a thread or threads or of wadding finely twisted
together. In such cases a suitable opening must be made in the side of the die fixed
to the pressure cylinder, so that the thread or threads or twisted wadding may be
drawn in through the opening and issue forth from the die in the heart of the
celluloidal fuse core. A guide may be placed within the die to ensure the strictly
central position of the textile cushion
A central textile cushion may, previously to its introduction into the fuse core
be saturated with any highly oxydizing solution so that the rate of combustion
of the fuse core may be thereby accelerated. For this purposo collodiou may
be used.
When the fuse core has to be squeezed out of the pressure cylinder in very fine
or thin forms, as when 11bs have to be formed on the outer au face, a small
percentage of vaseline may be added to the mixture before it is passed through
the hnending machine but vaseline has the drawback of giving out fumes of
caibonic oxide when the fuse is burned. It is desirable to avoid this drawback
to carefully mix the vaseline with an equal weight of pure niti oglycerine before
adding it to the other ingredients.
When a smaller proportion of nitroglycerine (say 38 parts) has been used in
the composition of the paste and more especially if dinitrated gun-cotton has been
mixed with it, the cord formed therewith is liable on leaving the pressure dic, to
swell out, thus diminishing its tensile strength and narrowing or obstructing air
channels.
But when the larger proportion of nitroglycerin, say 47 parts, has been used
and more especially if initiated gun cotton has been mixed with it, the swelling
on leaving the pressure die is very slight, the cord remains denso and of a good
tensile strength
Whether with 38 parts or with 47 parts, or with any intermediate proportion of
nitroglycerine and whether dinitrated or tiinitrated gun cotton has been used, the
celluloidal fuse core, when made as herein described, will carry fire in an efficient
manner even under great pressure, as when a fuse is squeezed flat in a blacksmith's
Even if the bichromate of potash be left out of an insufficient quantity used
the fuse core will still carry fire so long as it is not subjected to any great pressure.
It is not advisable to reduce the quantity discribed of bichromate."
vice.

page_text: Smooth surfaced celluloidal fuse cores may have air channels contrived around
them by the use of longitudinal threads placed at a sufficient distance from each
other, drawn down next to the fuse cole and covered over with a spiral tape
covering on with a number of spial threads touching each other so as to thatch
over the air channels left between the longitudinal threads which will in this way
give the same results whether as regards cushioning the core or assisting its
combustion ns external ribs on the fuse core would have given. Or all the threads
may, if desired, be placed spirally around the fuse core sufficient air spaces being
left between those next to it, with the covering spiral threads or tape running in
an opposite duection to that of the theads which they cover.
The external textile covering must, in all cases, be carefully varnished over
with an uncombustible varnish such as of kaolin, ochie or other similar carthy or
mineral matter, mixed with glue and applied on the outside
It is desirable that the minimum diameter or thickness of fuse core that
can conveniently be drawn down through the dies from the pressure cylinder,
be alone made use of, in order to avoid all risk of sparks being projected
through the external varnish and at the same time to diminish the cost of
the fuse.
A celluloidal fuse core can be composed and manufactured as herein described
20 as to have, as already stated, a good tensile strength, it can thus be safely
covered and vanished without the addition of any strengthening threads;-but it
is obvious that a fuse core of less intrinsic strength may have additional strength
given to it by suitable textile threads diawn down along with it through the
pressure die.
In every case, cushioning celluloidal fuse cores within and without whether by
atmospheric air, or by textile matter, or by combinations of the two will materially
weaken the effect of any chance blow and thus minimise the risk of accidents from
concussion to which all celluloidal fuse cores while in an uncushioned state are
more or less liable.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
alam 18:-
In an igniferous fuse with a celluloidal fuse core.
1. A fuse in which the igniferous material usually termed the fuse core tubularly
surrounds a resilient cushioning matter such as air or textile material.
2. A fuse in which the goiferous material forms a tube surrounded by and
containing within it, textile cushioning materials.
3. A fuse in which the igniferous material is exterioily provided with air
cushions formed by spacing the external covering or wrapping from the surface of
the core or from parts of said surface substantially as described.
4. The combination of an igniferous fuse core having projecting parts upon
its external surface leaving air filled cavities between said projecting parts,
with a textile cover surrounding said core and in contact with its projecting
parts.
6. A fuse in which the igniferous material is formed in such shape as to
constitute an attenuated wall having within it a cushioning matter such as air o
a textile material and surrounded by exterior cushioning matter such as textile
matter or all included by such textile matter or covering substantially in the
manner herein described.
6. The combination with an externally corrugated continuous fuse core of
an interior air or textile cushion and an exterior cushion the latter of textile
material enclosing air in the cavities of said corrugations, substantially as set
forth.
7. The combination with a fuse core composed of celluloidal paste of a textile
thread or threads embedded longitudinally within and in adhesion with the
material of said fuse core substantially as set forth.

page_text: 8. The combination of a thread or threads a tubular fuso core of continuous
celluloidal paste surrounding said thead and in adhesion therewith and an outer
toxtile covering substantially as and for the purposes set forth.
Dated this 24th day of September 1895.
HERBERT HADDAN & Co.,
18 Buckingham Street, Strand, London, W.C., Agents.