Year: 1895

page_text: Date of Application, 27th Dec., 1895
Complete Specification Left, 26th Oct., 1896-Accepted, 28th Nov., 1896
We, WILLIAM GREAVES, Chemist, and EDMUND MILLS HANN, Civil Engineer, both
of Aberaman, near Aberdare, County of Glamorgan, Wales, do hereby declare the
nature of this invention to be as follows:-
This invention relates to explosives, especially to the dynamite class, and the
nitro-compounds containing nitro-glycerine and gun-cotton.
The object of our invention is to prepare an explosive which shall be smokeless and
flameless, and can be employed for a variety of purposes such as blasting etc for which
the explosives of this type are not at present suitable.
Our invention consists in the addition to the explosive of the type mentioned of
ammonium oxalate, though we have found that ammonium acetate, ammonium
fortnate, or ammonium tartrate, either separately or mixed together give satis-
factory results, but we prefer to employ ammonium oxalate. Instead of the
ammonium salts we may employ the metallic salts for instance sodium or potassium
oxalate etc.
In working for instance with ordinary dynamite or carbonate we grind up
ainmonium oxalate or any of the other substances or mixtures of the same mentioned
above to as fine a powder as possible which is mixed with the kieselguhr before the
addition of the nitro-glycerine. The proportion of ammonium oxalate or other
agent employed may be varied according to the requirements of the explosive, and
we have found by experiment the larger proportion of ammonium oxalate used the
weaker is the explosive effect, and the lower the temperature of the products of com-
bustion. This explosive is therefore especially applicable for blasting in coal mines,
as being practically flameless there is no fear as in the present dynamite cartridge of
the explosive gases or the coal dust being ignited, and it has the additional advantages
that no noxious or irritating fumes are given off as is the case with other nitro-
explosives, and it is not as sensitive to a low temperature or concussion as ordinary
dynamite.
In some cases we may dispense with the kieselguhr, and simply add the ammonium
oxalate or other dilutent previously rendered anhydrous to the explosive.
Although we have referred to the application of this explosive to blasting it will be
understood that it is applicable to a variety of other useful purposes.
Dated this 27th day of December 1805

page_text: Improvements in or relating to Explosives.
We, WILLIAM GREAVES, Chemist and EDMUND MILLS HANN, Civil Engineer, both of
Aberaman, near Aberdare, County of Glamorgan, Wales, 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 explosives, especially to the dynamite class, and the
nitro compounds containing glycerine and gun-cotton.
The object of our invention is to prepare an explosive which shall be smokeless and
flameless, and can be employed for a variety of purposes such as blasting etc for which
the explosives of this type are not at present suitable.
Our invention consists in the addition to the explosive of the type mentioned of
ammonium oxalate. Instead-of-the-ammonium--salts-we-may-empley-the--metallie
salts-for-instance--sodium--or--potassium-oxalate-etc;-or-mixtures-i:e-ammonium
oxalate-and-potassium-oxalate. The salts may also be either hydrated or dehydrated.
dynamite we take 75%
For the explosive manufactured from the ordinary No:
dynamite and 25% ammonium oxalate which must be ground to as fine a powder as
possible. These are thoroughly mixed together either by hand or in any other safe
and convenient method, or for convenience we may first mix the above thoroughly
powdered oxalate with kieselguhr or other absorbent and then add the nitroglycerine
and knead in the usual way. For this latter we add 25% oxalate, 18% kieselguhr
and 57% nitroglycerine.
We find that the oxalate must be very finely powdered and that it must be also
uniformly and intimately mixed throughout the explosive-when this is obtained it
produces an explosive which works well, all the nitrous and nitric fumes being
neutralised and rendered harmless and it is safer than any other explosive at present
in use in fiery and dusty coal mines.
In applying our invention to carbonite we take 925 % of carbonite as ordinarily
made and 75% of the finely powdered oxalate. These are thoroughly mixed
together and produces an explosive less violent than ordinary carbonite and thus
better adapted for use in coal blasting and safer, for whereas, we have succeeded in
firing coal dust with ordinary carbonite yet when we have added the oxalate we have
found it impossible to do so; besides ordinary carbonite gives off noxious fumes
which render it very objectionable in places which are not well ventilated. By our
treatment these are neutralized.
When we add the oxalate to blasting gelatine it may be introduced immediately
after the complete solution of the nitroglycerine and collodion cotton or nitro-
cellulose and then after all the compounds are thoroughly mixed the explosive may
be allowed to cool and be worked up into cartridges in the ordinary way.
We find that 25% to 30% oxalate added to this explosive makes a safe blasting
compound according to the work for which it is required.
We do not find that it matters at what stage of the manufacture of the above the
oxalate is added provided that it is finely ground and it is thoroughly mixed with
the finished explosive.
"
In the case of gelignite or gelatine dynamite we find that from 20-30% of
In this case the
oxalate added makes a workable explosive for ordinary coal.
oxalate may be added to the "absorbent powder and then the nitroglycerine
introduced in the ordinary way and worked up into its commercial form by the usual
methods.
Ordinary dynamite, gelignite, carbonite and explosives of the same class as at
present made are too rapid in their explosion and thus destroy the coal but by

page_text: treating them according to our processes we obtain an explosive which does not
shatter the coal so much but at the same time its effects spread over a wider area
and thus in reality does more work.
We do not use a mixture of nitro-glycerine itself and oxalate as on account of the
physical properties of nitro-glycerine the resulting explosive is not free from
danger.
We do not bind ourselves to the above percentage which for other purposes may be
varied.
The oxalate--we We prefer to use is ammonium oxalate for the following
reasons:-
1. It commences to decompose at a low temperature and in so doing it absorbs a
large amount of heat.
2. It gives off a large volume of a mixture of gases which mixture is incombustible
and is a non-supporter of combustion.
3. No solid particles are formed during the decomposition.
Thus it largely
reduces the temperature of explosion of the accompanying explosive without perceptibly
diminishing its useful effects.
We have proved by continued experiments that to produce a useful explosive the
percentages to be used are governed on the one hand by the minimum quantity
of the oxalate etc necessary to produce a safe explosive and on the other hand a
maximum quantity to avoid a too great weakening of the explosive effects.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
1. A safety and flameless explosive formed by the mixture of ammonium oxalate
or-other-suitable oxalate with an explosive of the dynamite or nitro-glycerine classes
substantially as specified.
2. Safety and flameless explosives formed by the mixture substantially as and
in the proportions set forth of ammonium oxalate or--other-suitable--oxalate with
dynamite carbonite blasting gelatine gelignite or other explosives of these
classes.
Dated this 24th day of October 1896.
WILLIAM GREAVES
EDMUND MILLS HANN
Boult & Wade