GB2517660A - Priming device for an explosive charge - Google Patents

Priming device for an explosive charge Download PDF

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Publication number
GB2517660A
GB2517660A GB9521268.4A GB9521268A GB2517660A GB 2517660 A GB2517660 A GB 2517660A GB 9521268 A GB9521268 A GB 9521268A GB 2517660 A GB2517660 A GB 2517660A
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GB
United Kingdom
Prior art keywords
explosive charge
booster
priming
booster charges
priming device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9521268.4A
Other versions
GB2517660B (en
GB9521268D0 (en
Inventor
Michel Brule
Alain Kerdraon
Michel Vives
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.)
Nexter Munitions SA
Original Assignee
Nexter Munitions SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nexter Munitions SA filed Critical Nexter Munitions SA
Publication of GB9521268D0 publication Critical patent/GB9521268D0/en
Publication of GB2517660A publication Critical patent/GB2517660A/en
Application granted granted Critical
Publication of GB2517660B publication Critical patent/GB2517660B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C19/00—Details of fuzes
    • F42C19/08—Primers; Detonators
    • F42C19/0807—Primers; Detonators characterised by the particular configuration of the transmission channels from the priming energy source to the charge to be ignited, e.g. multiple channels, nozzles, diaphragms or filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C19/00—Details of fuzes
    • F42C19/08—Primers; Detonators
    • F42C19/0838—Primers or igniters for the initiation or the explosive charge in a warhead
    • F42C19/0846—Arrangements of a multiplicity of primers or detonators, dispersed within a warhead, for increased efficiency
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
    • G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
    • G01N11/16—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material by measuring damping effect upon oscillatory body
    • G01N11/162—Oscillations being torsional, e.g. produced by rotating bodies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/036—Analysing fluids by measuring frequency or resonance of acoustic waves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B1/00—Explosive charges characterised by form or shape but not dependent on shape of container
    • F42B1/02—Shaped or hollow charges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/028—Material parameters
    • G01N2291/02818—Density, viscosity

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Portable Nailing Machines And Staplers (AREA)
  • Fuses (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)

Abstract

A priming device for an explosive charge 2 comprises at least two booster charges 9 in the vicinity of explosive charge 2 and an initiator device 6,12 which simultaneously initiates the booster charges, the booster charges being designed and located with respect to the explosive charge so that the simultaneous initiation of all the booster charges initiates the explosive charge as a result of the addition of the shock waves 13 that they generate within the explosive charge, a single booster charge being unable to initiate the explosive charge.

Description

PRIMING DEVICE FOR AN EXPLOSIVE CHARGE
This invention relates to a priming system for an explosive charge contained, for instance, in a warhead (of a rocket, missile or bomb) or a munition.
Known priming systems most often comprise a primer and a bOoster. charge. Initiating the primer results in initiating the booster charge which initiates in turn the explosive charge.
Patent number FR8402487 thus shows a hollow-charge warhead with a known priming system.
The main disadvantage of such priming systems is that undesired priming Qf the explosive charge may occur in the event where the booster charge is accidentally initiated as a result, for instance, of a bullet or munition shrapnel hitting the booster charge.
Such a sensitivity is of great concern. It makes munition or warhead handling, dangerous and increases the storage area vulnerability.
* Up to now, attempts have been made to make explosive charges of-munitions insensitive to impacts but no solution has been proposed to make their priming systems insensitive.
* This is the purpose of this invention, which proposes a safety priming system insensitive to shocks and impacts on a single booster charge.
Thus, the invention provides a priming system for an explosive charge which comprises at least two booster charges in the vicinity of the explosive charge and an initiator device which simultaneously initiates the booster charges, the booster charges being designed and located with respect to the. explosive charge so that the simultaneous initiation of aL. the booster charges initiates the explosive charge as a result of the addition of the shock waves * that they generate within the explosive charge, a single booster charge being unable to initiate the explosive charge.
According to one particular embodiment, the booster * charges are identical and evenly distributed about the symmetry axis of the explosive charge.
Booster charges can be cylindrical and parallel to each other.
The priming system advantageously comprises three. booster charges.
According to another embodiment of the invention, the booster charges may be placed in a support block.
The support is preferably made of material with a shock impedance smaller than 107 kg/m2/s.
According to an embodiment of the invention, the initiator device comprises a disk made of priming, material which is in contact with the booster charges, the disk itself being initiated by a primen located in the symmetry axis of the explosive charge.
The initiator device may be advantageously * designed in such a way that it prevents backward initiation of booster charges by a single accidentally-initiated booster charge.
Thus, according to such an embodiment of the invention, the initiator device may comprise detonation wave transmission fuses which are initiated at the same time by a priming component with the fuses assembled in such a way that each fuse is in contact with all the others within at least one zone.
According to another embodiment intended to prevent backward initiation, the initiator device may comprise ttrespective primer for each booster charge and an electronic synchronizing system which ignites all the primers at the same time.
Other advantages of the invention will be apparent from the following description of a particular embodiment taken in connection with the accompanying drawings wherein: -Figure 1 is a longitudinal sectional schematic view of a warhead fitted with a priming system embodying the invention, taken, along reference line SB of Figure 2; -Figure 2 is a transverse sectional view of the priming system taken along reference line AA of Figure 1; -Figures 3a and 3b are longitudinal sectional views of another warhead fitted with a priming system embodying a variant of the invention, with Figure 3a being the sectional view taken along reference line DD of Figure 3b and Figure 3b being the sectional view taken along reference line CC of Figure 3a.
Referring to Figure 1, an explosive warhead 1 comprises an explosive charge 2 contained in an envelope 3. The warhead may be, for instance, a formed charge or a fragmentation warhead.
Bottom 3a of envelope 3 has an extension 4. onto which a plug 5 is screwed; this plug accommodates primer 6 (electrically initiated primer in the present case). A hole 7 is drilled through extension 4 with the hole axis coinciding with centerline 8 of explosive charge 2; The priming system comprises three mutually parallel cylindrical booster charges 9 which have each one end in contact with explosive charge 2. Booster charges 9 are identical and evenly distributed about symmetry axis 8 of explosive charge 2.
They are fitted into the bores of support block 10.
Support block 10 is made of aluminum alloy with an outside diameter equal to the inside diameter of envelope 3, and a cylindrical recess 11 in the same axis 8 as explosive charge 2 which accommodates a disk 12 made of priming material. Disk 12 is in contact with booster charges 9.
Diameter d and the component material of booster charges 9 are designed in such a way that the initiation of a single charge is not sufficient to initiate explosive charge 2 irrespective of the operating temperature. The craftsman will select the characteristics of booster charges 9 for the shock pressures required for initiating selected explosive charge 2.
BoosterS charges 9 are evenly distributed over a circle 14 of diameter ID about explosive charge axis 8. When all three booster charges 9 are initiated at the same time, the shock waves generated by each develop into the explosive charge from each booster charge (the shock wave generated by one of them is represented by the dotted lines 13 in Figure 1).
As the three booster charges are evenly distributed, the shock pressures generated by each of them are added with a maximum value substantially in explosive charge symmetry axis 8.
The value of D, and the number, diameter d and characteristics of booster charges 9 are to be chosen so that the addition of the shock pressures is sufficient for initiating the chosen explosive charge 2 irrespective of the operating temperature.
The design is to be such that the detonation of a single booster charge at the maximum operating temperature (around 70°C) does not initiate the main explosive charge and, conversely, the addition of the shock pressures generated by the booster charges at the minimum operating temperature (around -40°C) does initiate the main explosive charge whose operation should be nominal.
The priming system according to the embodinent combines the action of several booster charges and this achieves the desired result. The embodiment also provides a priming system which is much safer than known devices with a single booster charge. In fact, such prior art devices call for the use of relatively powerful booster charges to achieve initiation at low temperatures and this makes the device much more vulnerable at high temperatures.
The craftsman will easily determine the characteristic values of the priming system in view of the explosive charge characteristics.
To determine these values, a series of trials may be performed. First of all, the maximum dimensions (diameter d and height of booster charge 9) not to be exceeded to prevent explosive charge 2 from being initiated by a single booster charge 9 are to be established for a given explosive for explosive charge 2 and a given explosive for booster charge 9.
Next, the number of booster charges 9 and the minimum values for diameter d and diameter D which guarantee initiation of explosive charge 2 when all the booster charges are initiated at the same time, are chosen.
The preferred values to be selected are within the maximum and minimum limits thus determined so that only simultaneous initiation of all the booster charges can initiate explosive charge 2.
In particular, values at which closely spaced successive initiations (e.g., time interval of less than 0.1 milliseconds) of the three booster charges produce a combination of shock waves having an amplitude sufficient to detonate the explosive charge are to be avoided.
For example, with an explosive charge composed of one third of trinitrotoluene (TNT) and two thirds of oxinitro-triazole (ONTA), a priming system can be designed with three booster charges composed of: 94% by weight of hexogene, 5% by weight of wax and 1% by weight of graphite. Booster charge diameters d are chosen to be 15 mm and the booster charge heights are chosen to be mm. Diameter D is 25 mm.
With such parameter values, only the simultaneous initiation of all three booster charges can initiate explosive charge 2.
Simultaneous initiation in this case. is achieved by disk 12 which is itself initiated by primer 6 located in explosive charge symmetry axis 8.
Support block 10 can advantageously be made of a material having a shock impedance smaller than 107 kg/rn2 Is. Such an arrangement dampens out the radial diffusion of. the shock wave between all the booster charges. This prevents any disturbance of the shock waves transmitted to explosive charge 2. Priming system safety is thus improved.
Such an arrangement also improves the priming system resistance to bullet, or shrapnel impacts and precludes mutual initiation of the booster charges by influence effect.
A typical support block could be made of plastic material such as 6-polyamide or 6-6--polyamide (known under the trade name of Nylon) or else of porous material such as one of those described in Patent number FR2549949 (sintered metals or alloys, sintered metal oxides, sintered salts, glass or ceramic materials) As a variant, booster charges may not be parallel to each other but convergent. Such an arrangement amplifies the shock wave generated by the booster charges as described in Patent number FRB6O1001; this allows a priming system to be designed with still less powerful booster charges.
As a variant, each booster charge could be initiated by a specific primer with the initiation simultaneity achieved by an electronic system synchronizing the ignition of all the primers.
The advantage of such a variant is that the initiation of a single booster charge, due to the impact of a projectile for instance, cannot result in initiating the other booster charges through the initiator devices.
Figures 3a and 3b show a warhead in which the initiator devices of the priming system are designed according to another variant.
According to this variant, each booster charge 9 is initiated by a pellet 15 made of known priming booster charge material.
All pellets 15 are connected to a single priming component 16 through detonation wave transmission fuses 17.
Such fuses are well kncwn to the craftsman and most, often they comprise a lead or tin alloy shroud containing an explosive composition.
All the fuses have the same length and their ends facing priming component 16 are in the same plane for simultaneous transmission of the initiation provided by priming component 16 to the three fuses 17.
Each fuse 17 is located in a groove 18 provided on plate 19 which is itself arranged between support block 10 and bottom 3a of envelope 3. Grooves 18 connect a central bore 20 in the plate to the cylindrical housings for pellets 15.
The three fuses join up in bore 20 and are held assembled together over a portion L of their length so that they are in mutual contact in front of priming component 16.
The fuses can be held by adhesive or a binding thread and a filler material (such as synthetic resin) is then put into bore and over fuses 17 in grooves 18. This material holds the fuses in relation to plate 19.
These initiator devices operate as follows: Primer 5 initiates priming component 16 which initiates in turn all three fuses 17 at the same time. As the fuses have same lengths, the three pellets 15 are initiated simultaneously as well as the three booster charges 9 with which they are in contact.
In the event where an impact, of a projectile for instance, initiates a single booster charge, such an initiation cannot propagate to the remaining two booster charges.
In fact, on the one hand, support block 10 dampens out the radial transmission of the shock wave and, on the other hand, the initiator devices thus described prevent backward initiation from a booster charge to the others.
Thus, the initiated booster charge initiates in turn associated pellet 15 which transmits the initiation to fuse 17.
The detonation wave propagating through the mutual contact zone of the three fuses breaks the other two fuses, making them unserviceable and preventing backward initiation of the other two booster charges.

Claims (10)

  1. CLAIMS1. A priming device for an explosive charge, comprising at least two booster charges in the vicinity of the explosive charge, and an initiator device which simultaneously initiates the booster charges, the booster charges being designed and located with respect to the explosive charge so that the simultaneous initiation of all booster charges initiates the explosive charge as a result of the additionS of the shock waves that they generate within the explosive charge, a single one of the booster charges being unable to initiate the explosive charge.
  2. 2. A priming device according to claim 1, wherein the booster charges are identical and evenly distributed about a symmetry axis of the explosive charge - 3. A priming device according to claim 1 or 2, wherein the booster charges are cylindrical and parallel to each other.4. A priming device according to any preceding claim, comprising three booster charges.5. A priming device according to any preceding claim, wherein the booster charges are placed in a support block.6. A priming device according to claim 5, wherein the support block is made of material with a shock impedance smaller than 10' kg/m2/s.7. A priming device according to any preceding claim, wherein the initiator device comprises a disk made of priming material which is in contact with the booster charges, the disk itself being initiated by a primer located on a symmetry axis of the explosive charge.8. A priming device according to any of claims 2 to 6, wherein the initiator device comprises detonation wave transmission fuses which are initiated at the same time by a priming component, with the fuses assembled in such a way that each fuse is in contact with all the others within at least one zone.9. A priming device according to any of claims 2 to 6, wherein the initiator device comprises a respective primer for each booster charge, and an electronic synchronizing system which ignites all the primers at the same time.10. A priming device for an explosive charge, substantially as hereinbefore described with reference to Figures 1 and 2, or Figures 3a and 3b, of the accompanying drawings.Amendments to the claims have been filed as followsCLAIMS1. A priming device for a main explosive charge, comprising at least two booster charges in the vicinity of the main explosive charge, and an initiator device which simultaneously initiates the booster charges, the booster charges being designed and located with respect to the main explosive charge so that the simultaneous initiation of all booster charges initiates the main explosive charge as a result of the addition of the shock waves that they generate within the main explosive charge, a single one of the booster charges being unable to initiate the main explosive charge.2. A priming device according to claim 1, wherein the booster charges are identical and evenly distributed about a symmetry axis of the main explosive charge.
  3. 3. A priming device according to claim 1 or 2, wherein the booster charges are cylindrical and parallel to each other.
  4. 4. A priming device according to any preceding claim, comprising three booster charges.
  5. 5. A priming device according to any preceding claim, wherein the booster charges are placed in a support block.
  6. 6. A priming device according to claim 5, wherein the support block is made of material with a shock impedance smaller than io7 kg/m2/s.
  7. 7. A priming device according to any preceding claim, wherein the initiator device comprises a disk made of priming material which is in contact with the booster charges, the disk itself being initiated by a primer located on a symmetry axis of the main explosive charge.
  8. 8. A priming device according to any of claims 2 to 6, wherein the initiator device comprises detonation wave transthission fuses which are initiated at the same / time by a priming component, with the fuses assembled in such a way that each fuse is in contact with all the others within at least one zone.
  9. 9. A priming device according to any of claims 2 to 6, wherein the initiator device comprises a respective primer for each booster charge, and an electronic synchronizing system which ignites all the primers at the same time.
  10. 10. A priming device for a main explosive charge, substantially as hereinbefore described with reference to Figures 1 and 2, or Figures 3a and 3b, of the accompanying drawings.
GB9521268.4A 1994-11-03 1995-10-17 Priming device for an explosive charge Expired - Fee Related GB2517660B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR9413135 1994-11-03

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GB9521268D0 GB9521268D0 (en) 2013-12-25
GB2517660A true GB2517660A (en) 2015-03-04
GB2517660B GB2517660B (en) 2015-07-22

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GB (1) GB2517660B (en)
IT (1) ITMI952211A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019058072A1 (en) * 2017-09-25 2019-03-28 Arianegroup Sas Charge comprising an insensitive explosive charge element

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11060831B1 (en) * 2020-05-14 2021-07-13 The United States Of America As Represented By The Secretary Of The Army System and method for routing flame within an explosive device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2065840A (en) * 1979-12-19 1981-07-01 Messerschmitt Boelkow Blohm Detonator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2065840A (en) * 1979-12-19 1981-07-01 Messerschmitt Boelkow Blohm Detonator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019058072A1 (en) * 2017-09-25 2019-03-28 Arianegroup Sas Charge comprising an insensitive explosive charge element
FR3071600A1 (en) * 2017-09-25 2019-03-29 Arianegroup Sas LOAD COMPRISING AN INSENSIBLE EXPLOSIVE LOAD

Also Published As

Publication number Publication date
ITMI952211A0 (en) 1995-10-27
CA2161080A1 (en) 1996-05-04
GB2517660B (en) 2015-07-22
ITMI952211A1 (en) 1997-04-27
GB9521268D0 (en) 2013-12-25

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COOA Change in applicant's name or ownership of the application

Owner name: NEXTER MUNITIONS

Free format text: FORMER OWNER: GIAT INDUSTRIES

PCNP Patent ceased through non-payment of renewal fee

Effective date: 20151022