Compact Electric Detonator Assembly With Built-In EMI Filtering

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Solution Overview

Problem

Existing electric detonators fail to meet the 1W-1A no-fire standard for preventing accidental detonation due to stray voltage, electrical noise, or electromagnetic interference (EMI), which is crucial for modern guided weapons and satellite launch vehicles.

Innovation Solution

A compact electric detonator with a built-in EMI filter is designed, featuring a lead wire structure with a ferrite core EMI filter, glass-to-metal seals, and a heating wire with 1 Ω resistance, using insensitive explosives like ZrKClO4 and materials with high thermal conductivity and specific resistance to prevent accidental ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a powdered iron plug is molded around a lead wire to provide EMI protection, then EMI filtering capability is improved, but the lead wire structure becomes more complex and larger in size

Engineering Contradiction:

ImproveEMI filtering capabilityVSAvoidlead wire structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The EMI filter is integrated directly into the plug assembly structure, merging the EMI filtering function with the existing plug components rather than adding a separate molded structure around the lead wire. This reduces overall device complexity while maintaining EMI protection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The plug assembly is designed to serve multiple functions: it provides electrical connection, structural support, and EMI filtering capability through the ferrite core. This multi-functionality eliminates the need for separate EMI protection structures, reducing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If a powdered iron plug is molded around a lead wire to provide EMI protection, then EMI filtering capability is improved, but the overall device volume increases

Engineering Contradiction:

ImproveEMI filtering capabilityVSAvoiddevice volume

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The ferrite core EMI filter is nested within the existing plug assembly structure, utilizing the available space within the plug housing. This nested arrangement allows EMI protection without increasing the overall device volume.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Device complexity

If lead wire is used without EMI filter, then device simplicity is maintained, but accidental ignition risk due to EMI increases

Engineering Contradiction:

Improvedevice simplicityVSAvoidaccidental ignition resistance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The ferrite core acts as an intermediary component between the lead wire and external electromagnetic fields. It absorbs and dissipates EMI energy, preventing it from reaching the explosive charge. This simple intermediary element maintains device simplicity while significantly improving reliability by preventing accidental ignition.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The ferrite core changes the electromagnetic parameters of the lead wire assembly by introducing high permeability material that absorbs EMI. This parameter change enables the simple lead wire structure to achieve EMI protection without complex modifications.

Inventive Principle:

Principle #35Parameter changes

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

The solution effectively meets the 1W-1A no-fire standard by reducing EMI-induced ignition risks and ensuring reliable operation in electromagnetic environments.

Implementation Method 1

an electromagnetic interference (EMI) filter with a ferrite core to reduce electromagnetic interference

Methodology Applied

Scientific EffectElectromagnetic interference filtering: Absorption (EM radiation)

Implementation Method 2

The glass bead into which the first lead wire and the second lead wire are inserted may melt so that the first lead wire and the second lead wire and the plug housing form a glass-to-metal seal

Methodology Applied

Scientific EffectGlass-to-metal seal: Melting

Implementation Method 3

a heating wire with 1 Ω resistance

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS20260071856A1Compact electric detonator with built-in electromagnetic interference (EMI) filter and method of assembling the same

Publication Date: 2026.03.12 AGENCY FOR DEFENSE DEV

AI summary

There is provided a compact electric compressor with a built-in electromagnetic interference (EMI) filter, which can meet the 1W-1A no-fire standard. A compact electric detonator with a built-in EMI filter includes a lead wire composed of a first lead wire and a second lead wire, a cup into which a plug assembly is inserted, wherein the EMI filter through which the first lead wire and the second lead wire pass is installed on the plug assembly, and an adhesive that fixedly bonds an end of the plug assembly and the first lead wire and the second lead wire.