Lockable Base Bleed for Artillery Projectile

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Solution Overview

Problem

The existing base bleed systems in artillery projectiles face challenges with pressure fluctuations during ignition, leading to reduced precision and performance due to incomplete burning of the pyrotechnic gas generator and potential disruption from breech residues.

Innovation Solution

A device that controls the opening and closing of the base bleed using a non-return valve mechanism, ensuring rapid and uniform ignition by maintaining internal pressure until the pyrotechnic gas generator is fully activated, and protecting against environmental influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the base bleed is opened immediately upon firing to enable rapid ignition, then the ignition speed improves, but pressure fluctuations increase causing reduced accuracy

Engineering Contradiction:
Improveignition speedVSAvoidaccuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The base bleed is pre-prepared and positioned within the projectile structure before firing. The closure device is pre-configured to open automatically when propellant gas pressure exceeds a predetermined threshold, eliminating the need for complex ignition timing control during flight and ensuring consistent pressure conditions for accurate ignition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The closure device incorporates a pressure-sensitive mechanism that automatically responds to the actual propellant gas pressure conditions. When the pressure reaches the predetermined level necessary for reliable ignition, the closure opens; when pressure drops after the projectile exits the barrel, the closure automatically closes again, providing feedback-based pressure regulation.

Inventive Principle:
Principle #23Feedback

2Speed

If the pyrotechnic gas generator burns quickly to the surface for rapid ignition, then the ignition response improves, but the generator may extinguish itself when pressure drops after leaving the barrel

Engineering Contradiction:
Improveignition responseVSAvoidignition reliability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The pyrotechnic gas generator is pre-positioned and pre-prepared within the base bleed structure before firing. The closure device ensures that the generator burns under controlled pressure conditions until it reaches the surface, then automatically seals the base bleed to prevent pressure loss that would cause extinction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The closure device provides protective sealing before pressure loss occurs. By automatically closing the base bleed after the projectile exits the barrel, the system cushions against the sudden pressure drop that would otherwise cause the pyrotechnic gas generator to extinguish, ensuring continuous reliable operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If breech components are pushed into the base bleed during firing, then the base bleed structure is simplified, but gas generation is disrupted reducing performance

Engineering Contradiction:
Improvebase bleed structureVSAvoidgas generation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The closure device extracts and isolates the base bleed chamber from the breech environment. By providing a sealed boundary that opens only under specific pressure conditions, the device prevents breech components and residues from entering the base bleed, protecting the gas generation process while maintaining structural integration.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The closure device acts as an intermediary barrier between the breech environment and the base bleed chamber. It selectively permits propellant gases to enter for ignition while blocking other contaminants, mediating the interaction between the firing system and the base bleed to ensure reliable gas generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution ensures precise and efficient ignition of the pyrotechnic gas generator, minimizing pressure fluctuations and increasing the range and precision of the projectile by maintaining internal pressure until the effective phase of the base bleed begins.

Implementation Method 1

When the pressure level in the rear of the bullet, i.e., in the base bleed, exceeds the pressure level outside the base bleed, the device (re)closes the base bleed

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

A burning pyrotechnic charge in the base bleed generates a gas stream that is effective in the area behind the projectile

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

sufficient hot gases can penetrate into the base bleed in the gun barrel to ignite the surface of the pyrotechnic gas generator

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

The propellant gases act at high pressure on the rear of the projectile in the gun barrel

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3587995B1Base-bleed and projectile with a base-bleed
Publication Date: 2024.01.24 RHEINMETALL WAFFE MUNITION GMBH
  • EP3587995B1 patent drawingFigure 1~2

AI summary

A lockable base bleed (11) for a projectile (10) is proposed, wherein the device (4) closes the base bleed (11) when the pressure level in the base bleed (11) exceeds the pressure level outside the base bleed (11). The device (4) is preferably formed by a frame (5) with a crossbeam (5.1). The membrane (6) is attached to the crossbeam (5.1). The crossbeam (5.1) is preferably arranged centrally in the frame (5). The frame (5) and/or the membrane (6) can be round, oval, triangular, square, or polygonal.