Single Ignition Device for Cylindrical Fragmentation Charge

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Solution Overview

Problem

Cylindrical fragmentation charges face issues with achieving a rotationally symmetrical detonation front due to inconsistent ignition of boosters, leading to undesired splinter direction and asymmetrical pressure distribution, which is critical for correct functioning, especially in charges with plastic holders and pellet structures.

Innovation Solution

The use of a single ignition device with a modified booster, accompanied by damping materials and strategically designed booster shapes, such as diabolo or metal shells, to ensure simultaneous and symmetrical detonation front propagation, utilizing axial and radial damping elements to control shock wave propagation and achieve radial symmetry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two ignition devices with boosters are used to initiate the explosive charge simultaneously, then the detonation fronts can converge to build up excess pressure in the middle of the charge, but the boosters are rarely ignited at the same time leading to asymmetrical pressure distribution and undesired splinter direction

Engineering Contradiction:

Improvesimultaneous ignition of boostersVSAvoidnumber of ignition devices

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates one of the two ignition devices, using only a single ignition device with a modified booster design. This removes the complexity and reliability issues associated with coordinating multiple ignition devices while maintaining the essential function of generating a symmetrical detonation front.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention deliberately introduces asymmetry in the booster design (such as diabolo shape or off-center placement) to compensate for the absence of a second ignition device. This asymmetrical configuration ensures that the single booster generates a rotationally symmetrical detonation front in the explosive charge, resolving the contradiction between simplified device structure and reliable symmetrical operation.

Inventive Principle:

Principle #4Asymmetry

2Device complexity

If a single ignition device is used to simplify the system, then the device complexity is reduced, but the detonation front becomes asymmetrical and does not hit the pellet structure frontally

Engineering Contradiction:

Improvenumber of ignition devicesVSAvoidsymmetry of detonation front

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The invention applies local quality by modifying specific properties of the booster (such as its shape, density distribution, or explosive composition in different regions) to compensate for the single ignition source. This localized modification ensures that the detonation front propagates symmetrically throughout the charge, achieving the required precision without multiple ignition devices.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The modified booster acts as an intermediary element that translates the asymmetric input from a single ignition device into a symmetric output (detonation front). The booster's special design (diabolo shape, off-center position, or varied explosive composition) mediates between the single ignition source and the requirement for symmetrical detonation, ensuring frontal impact on the pellet structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional detonators are used, then the ignition system is simple, but the statistical ignition delay times of many microseconds cause asymmetry in detonation front propagation

Engineering Contradiction:

Improveignition system simplicityVSAvoidignition delay time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The invention incorporates preliminary action by pre-positioning the modified booster in a specific configuration that anticipates and compensates for ignition delays. The booster's design (such as pre-compressed explosive or optimized geometry) ensures that even with conventional detonator delay times, the detonation front propagates symmetrically, effectively pre-correcting for the time loss.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures a rotationally symmetrical detonation front, minimizing asymmetries and achieving optimal symmetry and voltage peak formation, even in cases where conventional detonators have ignition delays, by using materials like Teflon and copper for damping and ductile metals for shock wave initiation.

Implementation Method 1

when both ignition devices are ignited simultaneously, the detonation fronts converge and build up excess pressure in the middle of the charge

Methodology Applied

Scientific EffectDetonation: Detonation

Implementation Method 2

utilizing axial and radial damping elements to control shock wave propagation and achieve radial symmetry

Methodology Applied

Scientific EffectShock wave: Shock Wave

Data Source

PatentEP2982928B1Ignition device for a fragmentation charge

Publication Date: 2017.03.15 TDW GES FR VERTEIDIGUNGSTECHN WIRKSYST MBH

AI summary

Ignition devices for cylindrical charges often suffer from the problem of asymmetric initiation of the explosive charge. The proposed solutions enable point-like and linear initiations to be implemented almost symmetrically. The invention relates to an ignition device for a cylindrical fragmentation charge with at least one explosive charge (HE1, HE2) and with at least one ignition device that can be positioned axially on the main axis for initiating at least one booster.