Fusible Plug Venting for Ammunition Box Pressure Relief

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Solution Overview

Problem

Existing ammunition transport solutions fail to safely manage high temperatures and internal pressure, which can lead to critical situations such as self-ignition and fragmentation of ammunition, posing risks during transport.

Innovation Solution

Integration of a ventilation concept into an ammunition box with strategically placed blow-out openings filled with fusible materials or thin-walled plugs that open when critical temperatures or pressures are reached, allowing pressure relief while maintaining the box's structural integrity and environmental resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ammunition box is sealed to maintain environmental resistance and structural integrity, then waterproofing and dustproofing are improved, but internal pressure buildup occurs when exposed to high temperatures leading to fragmentation and lid blow-off

Engineering Contradiction:
Improveenvironmental resistanceVSAvoidinternal pressure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates fusible plugs made of materials with specific melting points (e.g., 190°F to 270°F) into the box structure before exposure to high temperatures. These plugs are positioned at strategic locations where they will melt and create venting channels when the box is subjected to thermal stress, preventing pressure buildup before it reaches critical levels that would cause fragmentation or lid blow-off.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state of the fusible plug material from solid to liquid at a predetermined temperature threshold. This phase change allows the plugs to automatically transition from a sealing function to a venting function, creating openings in the box wall when exposed to high temperatures during transport or storage, thereby relieving internal pressure while maintaining sealed conditions during normal operation.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If venting openings are integrated into the box wall to relieve internal pressure, then safety under thermal stress is improved, but waterproofing and dustproofing are compromised

Engineering Contradiction:
Improveinternal pressureVSAvoidenvironmental resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The fusible plugs are pre-installed into recesses or bores in the box wall structure, creating a sealed configuration during normal conditions. The plugs are dimensioned and material-selected to provide an effective seal against water and dust penetration while maintaining structural integrity of the box wall.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The fusible plugs undergo a temperature-dependent phase change from solid to liquid state. When the box is subjected to high temperatures (e.g., fire exposure or thermal runaway conditions), the plugs melt and create venting channels, allowing pressure relief. When cooled, the material can solidify again or be replaced, restoring the sealed configuration and environmental resistance.

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 reduces internal pressure and prevents self-ignition by allowing controlled venting, ensuring safe transport of ammunition without compromising the box's stability or environmental sealing.

Implementation Method 1

The fusible material has a melting point below the ignition temperature of the ammunition. When the ammunition case is subjected to such a high temperature, the material melts and vents the case.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

When the internal pressure increases and a predetermined internal pressure is reached, the stopper or the thin-walled material is pushed outwards.

Methodology Applied
Scientific EffectPressure force: Pressure Increase

Data Source

PatentEP2941619B1Ammunition box
Publication Date: 2018.03.14 RHEINMETALL WAFFE MUNITION GMBH
  • EP2941619B1 patent drawingFigure 1~3b

AI summary

The invention relates to a type of venting concept (IM venting) is integrated into a box (1), such as an ammunition box/case, which concept swings into action when the box (1) is exposed to a higher temperature and/or an internal pressure that could lead to critical situations builds up. The box (1) is used in particular to accommodate non-sensitive ammunition and comprises a cover (2) and a closure (4). In order to integrate the venting system (3), bore holes and/or through-holes (5) which are closed by means of a defined thin-walled material or plug (6) are placed in the box wall.