Improved Manufacture of Explosives from Nitrate of Ammonia and Resins.
Year: 1894

page_text: Date of Application, 12th Feb., 1894-Accepted, 17th Mar., 1894
COMPLETE SPECIFICATION.
[Communicated from abroad by LUDWIG KÖNIG, of No. 1, Feldstrasse, Berlin,
Germany, Merchant.]
Improved Manufacture of Explosives from Nitrate of Ammonia
and Resins.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, in County of
Middlesex, Consulting Engineer and Chartered Patent Agent, 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 :-
With explosives, the speed with which, on firing the ignition is conveyed from
one particle to the contiguous oues is of the first importance.
If this speed of transinission is comparatively slow in consequence either of the
particular chemical composition of the substances of which the explosive is made
up, or in consequence of the molecular structure thereof, the explosive action or
rupturing power thereof will be correspondingly small, because the gaseous pressure
will only attain its maximum effect. some time after ignition, while on the other
hand with great speed of transmission of the ignition a correspondingly greater
rupturing power will be produced.
In the manufacture of explosives from nitrate of ammonia and resins this fact
has not hitherto been sufficiently considered.
Heretofore when making explosives of this description (which owing to the
difficulty with which they are ignited are frequently termed "safety explosives")
the manufacture has generally been carried out by stirring or kneading the powdered
nitrate of ammonia together with melted resins, paràffine, wax, or the like, so as to
attain on the one hand an intimate admixture of the ingredients, and on the other
hand in order to surround the nitrate of ammonia with an envelope of the said
organic substances so as to prevent its partial volatilisation.
My correspondent has found that this method of manufacture is defective and
leads to the production of an explosive of low action because the body which is of
most importance for the transmission of the ignition throughout the mass of the
explosive, namely the nitrate of ammonia, is hindered in its effective transmission
of the heat generated by its decomposition, by the coating of organic material
which surrounds it.
According to the present invention this defect is obviated by means of a process
according to which, while an intimate admixture of the two substances nitrate of
ammonia and resin is insured, the necessary adhesion of the two substances which
is also essential for the effective action, is effected without entirely enclosing the
particles of nitrate of ammonia. The product obtained by this process appears
under the microscope as a mass of particles of nitrate of ammonia and resin
cemented together in such a manner that the resin only partially surrounds the nitrate
of ammonia, leaving a considerable part of the surface of the crystals uncovered
so that, on firing, a direct ignition, of one particle of nitrate of ammonia by another
can be effected.
In carrying out the said process, the nitrate of ammonia and resin are in the first
instance either pulverised separately and then mixed in the known manner, or they
are both pulverised together, or the pulverised nitrate of ammonia is mixed with
resin solution, the mixture being heated till the solvent is evaporated. In all these
cases mixtures are obtained in which the nitrate of ammonia and resin exist in a
finely divided condition. This product is then heated in suitable heating apparatus,
(by preference closed) until the resin begins to melt.

page_text: The particles of resin then adhere to the surrounding particles of nitrate of
ammonia. but as they are not actually melted, they cannot completely surround the
same, but leave, as above stated, a portion of the surfaces of the nitrate of ammonia
particles uncovered. The ignition can therefore, if suitably initiated, for example
by a detonator, be rapidly spread throughout the entire mass, and, as owing to the 5
partial adhesion of the organic substance to the nitrate particles, the rapid and
effectual combustion of the former is insured, the sudden evolution of a large.
volume of gases caused by this fact produces such a high degree of effectiveness
as has been heretofore exclusively obtained with nitrated explosives.
The cementing of the organic substance with the nitrate of ammonia has 1
furthermore the advantage that any separation of the two substances is prevented
such as might readily occur if mechanical shaking devices are employed for filling
cartridges.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I l
claim is :--
In the manufacture of explosives from nitrate of ammonia and resins, the
method of heating the two pulverulent ingredients, when intimately mixed with
each other, until the resin begins to melt, for the purpose of attaining the adhesion
of the two substances while preventing the complete surrounding of the nitrate 2
particles by the resin, substantially as described.
Dated this 12th day of February 1894
ABEL & IMRAY,
* Agents for the Applicant.