US3374127A - Compressed metal containing ternary explosive composition - Google Patents

Compressed metal containing ternary explosive composition Download PDF

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Publication number
US3374127A
US3374127A US570624A US57062466A US3374127A US 3374127 A US3374127 A US 3374127A US 570624 A US570624 A US 570624A US 57062466 A US57062466 A US 57062466A US 3374127 A US3374127 A US 3374127A
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United States
Prior art keywords
explosive
cartridge
explosive composition
electrodes
composition
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Expired - Lifetime
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US570624A
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English (en)
Inventor
Jenner Pierre
Sayous Leon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Societe Nationale des Petroles dAquitaine SA
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Societe Nationale des Petroles dAquitaine SA
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
    • F42D1/04—Arrangements for ignition
    • F42D1/045—Arrangements for electric ignition
    • F42D1/05—Electric circuits for blasting
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
    • C06B23/009—Wetting agents, hydrophobing agents, dehydrating agents, antistatic additives, viscosity improvers, antiagglomerating agents, grinding agents and other additives for working up
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B25/00—Compositions containing a nitrated organic compound
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
    • C06B31/28—Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/10—Initiators therefor
    • F42B3/12—Bridge initiators
    • F42B3/128—Bridge initiators characterised by the composition of the pyrotechnic material

Definitions

  • the detonation of an explosive charge is generally brought about by a primer or detonator, which in most cases consists of a small quantity of a very sensitive primary explosive, such as mercury fulminate, lead nitride or the like.
  • the primer is necessarily sensitive to shocks, heat, or weak electric currents and always represents a critical feature of an explosive assembly. For this reason, the statutes in numerous countries (for instance, in France) prohibit the storage of detonators close to explosive charges and vigorously forbid the storage of primed charges.
  • Another object of the invention is the provision of an explosive composition permitting the construction of a single cartridge, instead of a cartridge and a primer.
  • a further object of the present invention is the provision of an explosive composition to use in the production of a cartridge which is not sensitive to shocks.
  • a still further object of this invention is the provision of a cartridge combining the functions of an explosive material and a primer, which cartridge is simple in construction and safe in operation.
  • FIG. 1 is a sectional view of an explosive cartridge embodying the principles of the present invention.
  • FIG. 2 is a sectional view of a cartridge constructed in accordance with the teachings of the prior art.
  • FIG. 3 is an electrical circuit diagram with a sample of the composition being tested
  • the invention consists of an explosive composition made up of a known secondary explosive material mixed with a substance for lowering the electrical resistivity of the mixture and with an oxidizable and electrically conductive material having an intense heat release during combustion for initiating detonation by burning Within the charge.
  • a suitable explosive cartridge would be detonated by an electrical discharge acting upon an explosive composition which in the compact state would have an electric resistivity which, although allowing the passage of an electric current, would be sufliciently high to require the application of a voltage greater than 2000 volts to produce a current density between 0.1 and 1000 amp./c1n.
  • the voltage to be applied to cause the explosion of the cartridge would be in the order of 5000 to 50,000 volts and preferably 10,000 to 20,000 volts.
  • the secondary explosive material used in the car tridge may be nitroglycerine, pentaerythritol tetranitrate, cyclotrimethylene-trinitramine (Hexogen), trinitrotoluene (Tolite or TNT), ammonium nitrate, or nitrocotton.
  • the substances for lowering the resistivity of the explosive composition in the compact state may be one of various solid substances which are compatible with the secondary explosive material and which have a relatively low electric resistivity.
  • these substances are graphite, naphthalene, certain metal sulfides, such as iron disulfide. These substances are used in the form of fine powders.
  • the oxidizable, electrically conductive and strongly exothermic material is selected from strongly electropositive metals in powder form.
  • the metals of Groups II to VA of the periodic system, alloys formed of these metals or alloys of these metals with metals of other groups give good results.
  • Especially suitable for the purposes of the invention are: magnesium, aluminum, calcium, strontium, barium, zirconium, beryllium, antimony, silicon, ferrosilicon, and various magnesium alloys.
  • These oxidizable materials are preferably employed in the form of very fine powders, with an average particle size in the range from 0.01 to 1 mm.
  • the proportion of resistivity-lowering substances and of the oxidizable materials incorporated into the explosive may vary in accordance with the electrical and chemical properties of the secondary explosive concerned.
  • the proportion generally lies in the range between 1 and 20%, calculated on the weight of the mixture. In most cases, the proportion of each of these additives is between 3 and 10% by weight.
  • the mixture of these materials must be as homogeneous as possible.
  • the composition is compressed to obtain a compact mass, with a zone for accommodating the firing electrodes.
  • the compression is generally effected with 10 to 100 leg/cm. and in most cases with 20 to 60 kg./cm.
  • the mechanism of action of the oxidizable metal powder appears to be that of a firing relay: when two grains of this metal are traversed by an electric current, they become poles between which a small electric arc is established. These grains then burn by drawing oxygen from the explosive and thus initiate the detonation.
  • the voltage to be employed for detonating the new compositions can be predetermined by the nature and the quantities employed of the above-mentioned materials, so that the required safety margin can be established. It is possible to prepare charges which will explode only at 5000 v., 10,000 v. or 20,000 v. or at any other predetermined voltage. For this purpose, it suffices to confer to the explosive charge the appropriate electrical resistivity.
  • pure compacted penthrite has a resistivity of the order of 10 ohms/cm, While its resistivity falls to 1l000 ohms/cm. when mixed with 2% flaky graphite and magnesium powder; this resistivity value can be respectively reduced or increased by increasing or diminishing the graphite content.
  • the compressed compositions according to the invention have resistivities below ohms./cm., preferably not exceeding 10 ohms/cm.
  • a cartridge made in accordance with the teachings of the invention contains a charge made up of the explosive composition described above.
  • Two diametrically opposite electrodes are fixed in the charge and the extremities project beyond the charge. These external ends of the electrodes are provided with means for connecting them to conductor wires coming from a source of electrical energy.
  • the distance between the electrodes may vary greatly, but in most cases it is between 10 and 80 mm., more especially 30 mm.
  • a circuit for applying the voltage to the cartridge electrodes may consist of a capacitor in series with the conductors connecting the poles of a voltage source to the cartridge electrodes; the capacitor can be alternately connected with the voltage source and with the electrodes by means of a reversing switch.
  • the cylinder 1 represents a cartridge made up of a compact mass of secondary explosive containing about 10% of a resistivity-lowering substance and an oxidizable material, specifically a metal powder. Electrodes 2 and 2 are inserted into the explosive charge; the latter are simply uncovered metal wires such as copper. Electric leads 3 and 3' extend away from the cartridge and the electrodes.
  • FIG. 2 a cartridge 4 of the old type, containing a secondary explosive.
  • a conventional electrical detonator 5 contains a primer, i.e., a primary explosive, which is not present in the arrangement of FIG. 1, accord-ing to the invention. Because of the previously-described danger and by virtue of the existing regulations, when the cartridge 4 is intended for use in high-capacity blasting, as in mines or quarries, the detonator 5 is stored separately from the cartridge 4 and is placed within the latter only at the moment of use.
  • a DC. voltage source 6 is connected to a switch 7, whose movable arms are connected to a capacitor 8. At the same time, the leads 3 and 3 coming fro-m the electrodes 2 and 2' are connected to the corresponding terminals of the switch 7. In this manner, a strong electrical discharge, which is far more powerful than those hitherto employed, is applied to the electrodes through the capacitor 8.
  • a DC. voltage source 6 of 10,000 volts and a capacitor 8 of 2 microfarad may be employed.
  • Electrical energy of the order of 100 joules can be delivered in this manner, at a high voltage, where as the blasting boxes with magneto and capacitor discharge, used for firing by conventional electrical detonators, can deliver only 1 to 10 joules, at a voltage of the order of 500 volts in general, and a maximum voltage of 2000 volts.
  • the device made in accordance with the invention provides a very substantial safety factor, since this new explosive composition cannot explode either under the effects of an industrial A.C. voltage of 220 or 380 volts, nor under the effects of a voltage coming from a battery or a bank of accumulators.
  • the new composition is equally insensitive to induction effects due to a radio transmitter, even if the latter is powerful and located close to the explosive. It is insensitive to natural electrostatic discharges and in some cases also to violent mechanical shocks.
  • the electrical detonators or primers now in general use are very sensitive to all these effects.
  • Example 1 72 parts by weight of PETN powder (pentaerythritol tetranitrate) were coated with 20 parts by weight of molten TNT (trinitrotoluene). To this, 3 parts of graphite flakes and 5 parts magnesium powder were added, the mean particle size of the magnesium powder being 0.074 mm. The mixture was well homogenized, after which solid cylindrical cartridges (each weighing about 50 g.) were produced by pressing at 20 kg./cm. The cartridges were about 4 cm. high and had a diameter of about 3 cm.
  • Example 2 A cartridge similar to that of Example 1 was prepared with 82 parts by weight of PETN and 10 parts TNT, the proportions of the additives being the same as in the previous example. The cartridges thus obtained exploded in the same conditions as those in Example 1.
  • Examples 3-13 Cartridges similar to those in Example 1 were prepared by mixing various secondary explosives with 7% aluminum or magnesium powder, the particle dimensions of which did not exceed 0.074 mm, and with 3% carbon powder. These mixtures were compressed at 50 kg./cm. The cartridges were then tested for detonation with the arrangement of FIG. 3, using cylindrical electrodes of 30 mm. diameter, the bases of which were pressed against the base surfaces of the cartridge.
  • the following table indicates the voltages at which detonation occurred and the capacitances of the capacitor 8 for each of the explosive compositions tested.
  • An explosive composition consisting essentially of a compressed mixture of from 1 to 20% of a substance for lowering the electrical resistivity of the mixture, from 1 to 20% an oxidizable substance, and the rest a secondary explosive material, said secondary explosive material being selected from the group consisting of pentaerythritoltetranitrate, cyolotrimethylene-trinitramine, trinitrotoluene, ammonium nitrate, and nitrocotton, said substance for lowering the electric resistivity being selected from the group consisting of graphite, naphthalene and metal sulphides, and said oxidizable substance being selected from the class consisting of finely powdered magnesium, aluminum, calcium, strontium, barium, zirconium, beryllium, antimony, silicon, and ferrosilicon.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Air Bags (AREA)
  • Automotive Seat Belt Assembly (AREA)
US570624A 1965-08-13 1966-08-05 Compressed metal containing ternary explosive composition Expired - Lifetime US3374127A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR28241A FR1457461A (fr) 1965-08-13 1965-08-13 Nouvelle composition explosive

Publications (1)

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US3374127A true US3374127A (en) 1968-03-19

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US (1) US3374127A (enrdf_load_stackoverflow)
DE (1) DE1571238A1 (enrdf_load_stackoverflow)
FR (1) FR1457461A (enrdf_load_stackoverflow)
GB (1) GB1159975A (enrdf_load_stackoverflow)
NL (1) NL6611288A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3455750A (en) * 1967-12-29 1969-07-15 Hercules Inc Nonaqueous inorganic oxidizer salt blasting compositions containing silicon component of particular size
US3959041A (en) * 1973-04-03 1976-05-25 The United States Of America As Represented By The Secretary Of The Army Illumination and incendiary composition for explosive munitions
US4070970A (en) * 1975-05-14 1978-01-31 The Secretary Of State For Industry In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain & Northern Ireland Electro-explosive igniters
US20030075068A1 (en) * 2001-10-23 2003-04-24 Kim Chang Sun Structure of capsule for rapidly expanding metallic mixture
EP1323596A1 (en) * 2001-12-25 2003-07-02 Takata Corporation Initiator and gas generator
US20040231546A1 (en) * 2003-05-23 2004-11-25 Ofca William W. Safe electrical initiation plug for electric detonators
EP1742009A1 (fr) * 2005-07-05 2007-01-10 Institut Franco-Allemand de Recherches de Saint-Louis Composition explosive pour allumage thermique par source laser et son dispositif d'amorcage
NO20151689A1 (en) * 2015-12-09 2017-06-12 Interwell P&A As Ignitor, system and method of electrical ignition of exothermic mixture
CN110686567A (zh) * 2018-07-04 2020-01-14 南京理工大学 一种利用功能化碳纤维制备无桥电火工品的方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE8602984D0 (sv) * 1986-07-04 1986-07-04 Intermatch Ab Tendsats till pyrotekniska stryktendstickor
GB9027203D0 (en) * 1990-12-14 1991-04-24 Eev Ltd Firing arrangements

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US770046A (en) * 1904-03-07 1904-09-13 Roth Fa G Explosive.
US2754755A (en) * 1950-12-29 1956-07-17 Olin Mathieson Cored ammonium nitrate explosive cartridge
US2836484A (en) * 1955-05-04 1958-05-27 Reynolds Metals Co Aqueous metal powder explosive
US2887370A (en) * 1957-02-12 1959-05-19 Reed E Donnard Non-corrosive percussion primer material
US2954284A (en) * 1958-02-13 1960-09-27 Ohio Commw Eng Co Fuel comprising a mixture of ammonium nitrate and metal particles
US2970047A (en) * 1958-06-05 1961-01-31 Thomas Q Ciccone Conductive priming mixture
US2996007A (en) * 1958-08-25 1961-08-15 Philip J Franklin Explosive train
US3004842A (en) * 1958-02-04 1961-10-17 Canadian Ind Ammonium nitrate explosives and their manufacture
US3090310A (en) * 1960-05-04 1963-05-21 George W Peet Conductive explosive primer mixture and device
US3156186A (en) * 1961-03-17 1964-11-10 Gen Precision Inc Ammonium nitrate-aluminum explosive
US3160537A (en) * 1961-10-12 1964-12-08 Catalyst Research Corp Heating composition
US3278353A (en) * 1956-12-03 1966-10-11 Remington Arms Co Inc Ammunition priming composition comprising aromatic hydroxy compounds

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US770046A (en) * 1904-03-07 1904-09-13 Roth Fa G Explosive.
US2754755A (en) * 1950-12-29 1956-07-17 Olin Mathieson Cored ammonium nitrate explosive cartridge
US2836484A (en) * 1955-05-04 1958-05-27 Reynolds Metals Co Aqueous metal powder explosive
US3278353A (en) * 1956-12-03 1966-10-11 Remington Arms Co Inc Ammunition priming composition comprising aromatic hydroxy compounds
US2887370A (en) * 1957-02-12 1959-05-19 Reed E Donnard Non-corrosive percussion primer material
US3004842A (en) * 1958-02-04 1961-10-17 Canadian Ind Ammonium nitrate explosives and their manufacture
US2954284A (en) * 1958-02-13 1960-09-27 Ohio Commw Eng Co Fuel comprising a mixture of ammonium nitrate and metal particles
US2970047A (en) * 1958-06-05 1961-01-31 Thomas Q Ciccone Conductive priming mixture
US2996007A (en) * 1958-08-25 1961-08-15 Philip J Franklin Explosive train
US3090310A (en) * 1960-05-04 1963-05-21 George W Peet Conductive explosive primer mixture and device
US3156186A (en) * 1961-03-17 1964-11-10 Gen Precision Inc Ammonium nitrate-aluminum explosive
US3160537A (en) * 1961-10-12 1964-12-08 Catalyst Research Corp Heating composition

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3455750A (en) * 1967-12-29 1969-07-15 Hercules Inc Nonaqueous inorganic oxidizer salt blasting compositions containing silicon component of particular size
US3959041A (en) * 1973-04-03 1976-05-25 The United States Of America As Represented By The Secretary Of The Army Illumination and incendiary composition for explosive munitions
US4070970A (en) * 1975-05-14 1978-01-31 The Secretary Of State For Industry In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain & Northern Ireland Electro-explosive igniters
US20030075068A1 (en) * 2001-10-23 2003-04-24 Kim Chang Sun Structure of capsule for rapidly expanding metallic mixture
US6759798B2 (en) * 2001-10-23 2004-07-06 Chang Sun Kim Structure of capsule for rapidly expanding metallic mixture
EP1323596A1 (en) * 2001-12-25 2003-07-02 Takata Corporation Initiator and gas generator
US20040231546A1 (en) * 2003-05-23 2004-11-25 Ofca William W. Safe electrical initiation plug for electric detonators
EA009339B1 (ru) * 2003-05-23 2007-12-28 Дино Нобель, Инк. Безопасная электрическая инициирующая свеча для электрических детонаторов
EP1742009A1 (fr) * 2005-07-05 2007-01-10 Institut Franco-Allemand de Recherches de Saint-Louis Composition explosive pour allumage thermique par source laser et son dispositif d'amorcage
FR2888234A1 (fr) * 2005-07-05 2007-01-12 Saint Louis Inst Composition energetique dopee optiquement
US20070113941A1 (en) * 2005-07-05 2007-05-24 Deutsch-Franzosisches Forschungsinstitut Saint-Louis Optically doped energetic igniter charge
US7784403B2 (en) 2005-07-05 2010-08-31 Deutsch-Franzosisches Forschungsinstitut Optically doped energetic igniter charge
NO339580B1 (no) * 2005-07-05 2017-01-09 Deutsch Franzoesisches Forschungsinstitut Saint Louis Optisk dopet energirik tennsats
NO20151689A1 (en) * 2015-12-09 2017-06-12 Interwell P&A As Ignitor, system and method of electrical ignition of exothermic mixture
CN110686567A (zh) * 2018-07-04 2020-01-14 南京理工大学 一种利用功能化碳纤维制备无桥电火工品的方法

Also Published As

Publication number Publication date
GB1159975A (en) 1969-07-30
NL6611288A (enrdf_load_stackoverflow) 1967-02-14
FR1457461A (fr) 1966-01-24
DE1571238A1 (de) 1971-02-18

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