Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF TllE INVENTION
1. Field of the Invention
The present invention relates to a method
and apparatus of initiating detonation of liquid explo-
sive compositions and, more particularly, to a novel
such detonator constituting a detonationa amplifier used
to trigger or activate a larger quantity of bulk liquid
explosive.
2. ~rief Description of the Prior Art
In the past, it has been the conventional
practice to employ solid explosives for a variety of
applications. The solid explosive is detonated by the
use of a pyrotechnic device such as an initiator cap
which is activated by percussion or electrical means.
However, such a simplified detonation cannot be readily
achieved when using certain classes of l;quid explosives
which1 by their very nature, are less sensitive to initi-
ation with conventional caps. Current art for detonating
such liquid explosives involves adding sensitizing agents
to increase the mixtures shock sensitivity to an extent
which permits them to be detonated with conventional caps.
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An alternate method within the current art requires the
use of a high explosive booster charge. Both of these
techniques increase the saftey hazards for persons using
the system as well as to proper~y and equipment. Explo-
sives, which can be h.~n~ J in liguid form, are well known
and do find valuable applications in the fields of mining
and quarrying as well as in oil proc3uction and the like.
A considerable effort has been directed to producing
powerful liquid explosives and systems employing liquid
explosives. However, liquid explosives have the charac-
teristic disadvantage of being very sensitive to spurious
shocks which detonate the explosive composition. Trans-
portation and use of these shock sensitive explosives
require extreme caution.
Attempts have been made to effectively transport
such liquid or semi-liquid explosive compositions by
adding a third composition such as a gel so that the
resultant compound is comparatively insensitive to
detonation by spurious shocks. The addition of the gel
greatly reduces the usefulness of the explosive compo-
sition inrJsmuch r3.s a re]r3tively solid or scmi-soli(3
explosive compound results which limits the application
or usage thereof. For example, liquid compositions are
desirable for use in rocks and crevices so that available
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openings are totally occupied by the liquid explosive
composition. Semi-solid or solid explosives cannot be
effectively used in such applications.
When utilizing separate liquid ingredients, the
separate ingredients constituting the explosive composition
may be shipped and stored in separate containers for safety
and subsequently combined in proper proportion at the
operating site where the explosive composition is to be
used. However, detonation of the composition is relatively
unstable and, therefore, convnetional liquid compositions
are normally discouraged from being used. Experience with
such liquid compositions has indicated one or more of the
following characteristic disadvantages. Combining and/or
mixing the ingredients is a hazardous operation, especially
under field conditions. Also, one or more of the ingredients
is highly toxic and is hazardous to personnel who handle
or mix the liquid ingredients. The composition, once mixed,
is shock sensitive and, therefore, hazardous and difficult
to dispose of without either detonating the composition
immedicately or contaminating the environment. Furthermore,
the composition has a short useful life and must be detonated
quickly or disposed of which presents additional problems.
The composition based on such ingredients requires a large
explosive charge as a booster to reliably initiate detonation.
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Such a booster entails additional procedures, expense and
handling.
Therefore, there has been a long standing need to
provide a liquid explosive composition which may be readily
handled at the operational site and detonated without hazard
to personnel handling or mixing the ingredients of explo-
sive systems or initiating the detonation. In particular,
by employing ingredients which are normally considered
insenstive to shock and by separately transporting and
storing the ingredients in separate containers, mixture
can be taken at the site of use without hazard. The
characteristic disadvantages of liquid compositions may
be achieved by avoiding the need for high sensitive liquid
mixtures and/or powerful booster charges through the use
of a novel detonation amplifier as will be described
hereinafter.
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SUMMARY OF THF INVENTION
Accordingly, the above problems and difficulties
are obviated by the present invention which provides a
novel method and apparatus for detonating liquid ex-
plosive compositions which include employing a container
for holding a bulk quantity of liquid composition composed
of ingredients normally insensitive to spurious shock
detonation. a detonating amplifying means is immersed
into a portion of the bulk liquid composition which
includes a pyrotechnic charge adapted to be remotely
ignited or activated so as to detonate a limited portion
of the bulk explosive which subsequently detonates the
entire bulk quantity. In one form of the invention, the
detonator amplifier takes the form of an apertured chamber
hou-sing the pyrotechnic charge which is submerged into
the liquid explosive composition so that a portion of the
liquid enters the chamber and surrounds the charge. In
another form of the invention, a shaped charge is carried in
fixed spaced apart relationship with respect to a baffle
whereby a reflected shock wave initiates explosion of a
small ~ortion of the bulk which results in subsequent
detonation of the entire bulk quantity of liquid explosive
composition.
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Therefore, it is among the primary objects of the
present invention to provide a novel method and apparatus
of detonating large quantities of liquid explosive compo-
sition utilizing a detonator amplifier means without the
use of a large booster charge and which can be empioyed
to initiate detonation in bulk quantities of certain
chemicals, such as nitromethane, which is normally so
insensitive to shock as to not normally be classed as an
explosive.
Still another object of the present invention is
to provide a novel method and apparatus for detonating
liquid explosive compositions which employs a detonation
flmplifier submerged within a bulk quantity of the liquid
explosive composition whereby a portion of the bulk
composition is triggered or activated in such a manner
as to subsequently detonate the remaining bulk composition.
Yet another object of the present invention is to
provide a novel apparatus and method for detonating ex-
plosive compositions comprised of liquid ingredients which
is non-toxic and is not hazardous to handle or mix at the
site of operation with respect to personnel or equipment.
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Another object of the present invention is to
provide a novel method and apparatus for detonating liquid
explosive composition which does not require a large
explosive charge as a booster so as to reliably initiate
the detonation and which employs liquid ingredients that
may be readily combined or mixed at the site under field
conditions without undue hazard or danger to handling
personnel.
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BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are
believed to be novel are set forth with particularity in
the appended claims. The present invention, both as to
its organization and manner of operation, together with
further objects and advantages thereof, may best be
understood by reference to the following description,
taken in connection with the accompanying drawings in
which:
FIGURE 1 is a side elevational view of a container
holding a bulk quantity of liquid explosive composition
and having a portion of the container broken away illus-
trating the novel detonation amplifier of the present
invention submerged in the bulk composition;
FIGURE 2 is an enlarged cross-sectional vlew of
the detonation amplifier shown in FIGURE l;
FIGURE 3 is a side elevational view of a container
holding a quantity of liquid explosive composition and
incorporating a detonation amplifier of a different
embodiment;
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FIGURE 4 is an enlarged side elevational view of
the different detonation amplifier as shown in the
apparatus of FIGURE 3; and
FIGURE 5 is a transverse cross-sectional view of
the shaped charge detonation amplifier shown in FIGURE 4
as taken in the direction of arrows 5-5 thereof.
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DESCRIPTION OF TH~ PREFERRFD EMBODIMENT
Broadly, the present invention comprises a shock-
producing device which may be referred to as a detonation
amplifier that is constructed and employed in a ~lanner
which precludes personal injury or accidental damage in
the event of inadvertent initiation during handling or
storage of a liquid explosive composition. Also, the
shock-producing device or detonation amplifier may com-
prise a system of baffles or chambers which confine or
partially confine a portion of the liquid to be detonated
and/or to direct or focus the shock and/or detonation
waves traveling through the liquid in a manner which
permits the shock produced by the shock-producing device
to detonate a liquid charge which it could not otherwise
detonate. Embodiments of the shock-producing or detonation
amplifying devices are shown in FIGURES 1 and 2 and FIGURES
3-5 inclusive respectively.
Referring to FIGURE 1, the present invention in-
cludes a container 11 which holds a bulk quantity of
liquid explosive composition 12 into which a shock-producing
or detonation amplifying device 10 is submerged. The
device includes means immediately adjacent to a prede-
termined portion of the bulk liquid explosive composition
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into which a small pyrotechnic charge 22 is disposed.
The charge is activated in a suitable means such as via
electrical wires 24 which may be attached to a suitable
actuator. As one example of liquid explosive composition
12, a two component explosive ingredient composition
could consist of a common industrial solvent
such as nitroethane which is mixed or blended with a
commercial grade of nitric acid wherein the mixture
occurs at the operational or using site. Nitroethane is
an industrial solvent that is readily available in abundant
supply at a reasonable or low cost. The physical properties
of nitroethane are such that it is inherently safer to
use than a large quantity of solvents commonly used in
commercial coatings. For example9 the lower limit of
flammability of nitroethane is 3.4% by volume in air as
compared with 1.9%, 1.0% and 2.15% for methyl isobutal
ketone, xylene and acetone respectively. Similarly, the
flash point of nitroethane (TCC) is 87F as compared to
flash points of 0F, 24F and 81F for acetone, methyl-
ethyl ketone and xylene respectively.
The ,other ingredient of the two component composition
is a commercial grade nitric acid which is similarly an
abundant, readily available, low cost ingredient. The
nitric acid found to be useful as a sensitizer for nitro-
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ethane is aqueous nitric acid which contains from 60~ to
75% nitric acid. The nitric acid ingredient as well as
the nitroethane ingredient may be separately transported
and shipped with little or no difficulty using ordinary
precautions.
In practice, the two component bulk liquid
explosive composition 12 is prepared by mixing the proper
weight of nitric acid (HNO3) and nitroethane (CH3CH2NO2)
in a clean container 11 as the explosive composition is
needed at the operational or using site. The nitroethane
is totally miscible in aqueous nitric acid solution over
a wide temperature range as long as the acid content of
solution is at least 60%. Nitroethane is immiscible with
the nitric acid in concentrations less than 58% acid.
Further details concerning the mixture of the two
ingredients to form the liquid explosive composition are
set forth in U.S. Letters Patent Number 4,630,540, issued
December 23, 1986.
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Referring now in detail to FIGURE 2, the shock-
producing or detonation amplifying means 10 comprises a
small pyrotechnic charge such as a mild cap 22 which is
piaced inside a small detonation chamber 16 having the
inside surface 21 directly opposing and in fixed space
relationship with respect to the charge 22. It is noted
that the bottom 18 and top 20 are provided with openings
or vents 28 and 26 respectively which permit thz liquid
explosive composition to flow into the interior of the
chamber 16. It is to be noticed that the top lid or wall
20 may be readily removed from the chamber in order to
insert or remove the charge 22 when desired. The chamber
16 is submerged into the surrounding bulk liquid composition
12 at which time a portion of the composition flows into
the interior of the compartment. The apparatus or means
10 takes the form of a detonation amplifier employing an
enclosed chamber 16 which is identified by the numeral
14 as an overall amplifier means.
If desired, additional safety devices such as an
electrical or pyrotechnic safe arm device may be employed
in place of a conventional cap 22 which is illustrated.
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The si~e und type of pyro~echnic char~e 22 and the
size of the chamber defined by wall 21 as well as the vent
openings or holes 26 and 28 are selected so that in event
of accidental ignition, the products of detonation will
be sufficiently confined to preven~ injuries to personnel
handling the device and to prevent ignition of similar
nearby devices. Also, the size and type of charge is
selected so that when initiated, the pyrotechnic device
22 will reliably cause detona~ion of the liquid within
the confines of the chamber 16 which will subsequently
detonate the surrounding bulk liquid explosive composition
external of the chamber 16. Detonation of the liquid
explosive composition confined within the chamber insures
rellable detonation of the remainder of the bulk liquid
explosive composition 12.
Referring now in detail to FIGUR~S 3, 4 and 5,
another embodiment of shock-producing or detonation amplifier
means is illustrated in the general direction of arrow
30 consisting of a pyrotechnic cap or charge 36 which,
when initiated via igniter line 48, initiates detonation
in a length of linear shaped charge 38 which produces a
shock wave in the liquid 46 such as the nitromethane and
nitric acid composition noted above. The shock wave is
reflected against a baffle plate 40 in a manner which
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causes detonation of that portion of the liquid explosive
composition between the linear shaped charge 38 and ~he
baffle plate 40-and, ultimately, detonation of the entire
liquid explosive composition 34. Brackets 42 and 44
interconnect the baffle plate 40 with the cap 36 and the
charge 38. The overall container is identified by numeral
32 and contains the bulk quantity of liquid explosive
composition 34 into which the pyrotechnic detonation
amplifier 30 is submerged.
Therefore, it can be seen that the inventive
detonatioh amplifier means taking the form of the chamber
version indicated by numeral 10 or the shaped charge version
including the baffle shown by numeral 30 provides a means
whereby a comparatively safe and insensitive liquid, such
as nitromethane, can be used without the employment of
additional sensitizers or other chemicals normally re-
quired for safe detonation. Also, the inventive concept
can be readily inserted into the liquid explosive compo-
sition, then removed and drained to return it and the
liquid to their like-new condition so as to permit a
placed charge to be safely and easily disarmed and either
reused at a later time or disposed of as required. By
using either the detonation amplifier 10 or 30, a small
portion of the bulk explosive composition is detonated
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which, in turn, subsequently causes the total explosion
of the remaining bulk of the composition within the
container.
While particular embodiments of the present
invention have been shown and described, it will be
obvious to those skilled in the art that changes and
modifications may be made without departing from this
invention in its broader aspects and, therefore, the
aim in the appended claims is to cover all such changes
and modifications as fall within the true spirit and
scope of this invention.
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