for Fulminating Compounds in general.
Year: 1885

page_text: for Fulminating Compounds in general.
I GUSTAV BLOEM, Manufacturer, residing at Düsseldorf in the Kingdom of
Prussia, Empire of Germany, do hereby declare the nature of said invention
and in what manner, the same is to be performed to be particularly described and
ascertained in and by the following statement :-
The invention relates to an improved construction of the shell of detonators or
blasting caps filled with a fulminating compound and used as primers to explode
large blasts or charges of gun powder, dynamite gun cotton or similar substances.
The effect of an explosive such as gun powder, dynamite, gun cotton and others
is so much better and greater in proportion as the first impetus by which the.
explosive is caused to explode is greater and more concentrated. Therefore
blasting caps or detonators filled with fulminate of mercury are commonly used.
This fulminate is enclosed in the blasting caps as hitherto used in a metal shell:
a cylindrical copper tube a, the bottom b of which is closed as shown in Figure 1.
If it were possible to concentrate the effect of the explosion of the fulminate still
more into one direction by a certain construction of the shell the impetus would
thereby become much greater and more effective than by the usual blasting caps in
which the gases can expand in all directions. Such improved blasting caps would
increase considerably the effect of the explosive employed.
The present invention has for its object the production of such improved
blasting cap, or rather the shell of it, whilst the filling material, the fulminating
compound, remains as heretofore. The main feature of the invention is based upon
the weakening of the bottom b. Figure 1 of the shell a as compared with its
cylindrical part, or the re-enforcement or strengthening of the latter as compared
with the former, which may be attained in different ways, and which will con-
centrate the effect of the exploding fulminate in a direction axially of the
detonator.
A thickening of the material of the shell a as far as it is filled with the
fulminate as shown in Figure 2, is accompanied by only a comparatively small
effect. The constructions represented in figures 3 to 8 of the drawing answer on
the other hand very effectively.
The bottom b of the shell a is pierced without disengaging therefrom any
portions of the bottom as represented at Figure 3. The bottom so opened is again

page_text: closed as represented by Figure 4 by pressing it between suitable dies, so that
there is no difference in the external appearance of such improved shell and the
usual old one. By these means the following result is attained; the gases of the
explosion encountering the least resistance at the bottom b are directed to this
place by the stronger cylindrical portion of the shell a, and, concentrated in an
axial direction thereby producing a very intense effect.
Figure 5 shows the bottom bundisturbed and solid, but hemispherically (or nearly
so) pressed inwardly so as to bring the line of weakest resistance into the circular
edge of the shell a and the bottom b.
But the modifications embodied in Figure 6, 7, and 8 are still more effectual.
In this case the shell a is surrounded as far as the fulminating compound extends
by a sleeve c (or by more than one) grasping by a narrow inward rim d under the
edge of the bottom b. The latter may furthermore if found convenient, be ripped
open as described above. The sleeve c (or the sleeves) may project from the outside
of the shell a as represented in Figures 6 and 8, or be flush with it as represented
in Figures 7 in which latter case the inside diameter of the shell a at this place
becomes smaller in proportion.
By these constructions the concentration of the effect of the explosion in an axial
direction is strikingly increased. Whilst the detonator heretofore used forces a
conical indentation of a base of inch diameter into a lead sheet of inch thickness
without penetrating it; the new improved detonator or blasting cap penetrates the
lead making a nearly cylindrical hole of half an inch diameter therein.
The improved shell is used in detonators or blasting caps for gunpowder and
dynamite cartridges as well as for gun cotton and other explosives.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In detonators or blasting caps, the shell a, the bottom 6 of which is first
pierced and then again closed, substantially as described and for the purpose
stated.
2. In detonators or blasting caps the shell a the bottom 6 of which is hemi-
spherically (or nearly so) pressed inwardly, substantially as described and shown in
Figure 5 and for the purpose stated.
3. In detonators or blasting caps the employment of a separate metal sleeve c
(or more than one) surrounding the shell a as far as the fulminating compound
extends, and having an inward rim d in combination with a solid and undisturbed
bottom b, or with a ripped open bottom 6 substantially as described and represented
in Figures 6, 7, and 8 and for the purpose stated.
4. In detonators or blasting caps the thickening of the material of the shell a
as far as the fulminating compound extends in combination with a solid and
undisturbed, or with a ripped-open bottom b substantially as herein shown and
described and for the purpose stated..