Reach-Compliant Pyrotechnic Delay Composition with Variable Burning Time
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Solution Overview
Problem
Existing pyrotechnic delay compositions are toxicologically problematic and have limitations in controlling burning time and slag formation, leading to potential munition failures under dynamic conditions.
Innovation Solution
A delay composition comprising primary iron oxides, zirconium or zirconium hydride as reducing agents, slag-forming additives like ferrosilicon and tungsten, framework-forming additives such as aluminosilicates and silicate glasses, and a mineral binder, allowing for variable burning time and enhanced slag formation to prevent burning front disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional delay compositions containing lead compounds, chromium compounds, nickel compounds, barium compounds or perchlorates are used, then the burning time can be controlled, but the compositions become toxicologically problematical for human beings and the environment
Solution Approach 1:
The patent changes the chemical composition parameters by replacing toxic substances (lead compounds, chromium compounds, nickel compounds, barium compounds, perchlorates) with non-toxic alternatives (iron oxides, zirconium, silicon, aluminum powders). This parameter substitution maintains the burning time control functionality while eliminating toxicological hazards, achieving both burning time controllability and environmental safety.
Solution Approach 2:
The patent creates a composite material system combining iron oxides, zirconium, silicon, aluminum powders, and organic binders in specific ratios. This composite approach enables the formulation of non-toxic delay compositions that maintain controlled burning characteristics through the synergistic interaction of multiple components, replacing harmful single-substance compositions with safe multi-component systems.
2Illumination intensity
If thermite mixture of iron oxides and metal powders is used, then the composition can be ignited and produces liquid iron, but the burning time can be controlled to only a very limited extent by changing the stoichiometric composition
Solution Approach 1:
The patent extends burning time control versatility by introducing multiple independent parameters: oxidizing agent type and amount, reducing agent type and amount, slag-forming additive concentration, and framework-forming additive concentration. This multi-parameter formulation allows continuous adjustment of burning time from 0.2s/cm to 4.0s/cm while maintaining the thermite reaction's glowing liquid iron production, overcoming the limited stoichiometric adjustment range of traditional thermite mixtures.
3Reliability
If delay composition produces too little slag or fluid slag that does not solidify quickly, then the burning front can be maintained, but the stresses on firing can lead to the slag being torn away from the burning front causing munition failures
Solution Approach 1:
The patent introduces framework-forming additives (aluminosilicates, silicate glasses, amorphous polysilicic acids) as intermediary substances that mediate between the molten slag and the burning front. These additives create a framework structure that reinforces the slag mass, preventing it from being torn away by firing stresses while maintaining the necessary fluidity for continuous burning front protection. The framework-forming additives act as a structural mediator that bridges the gap between slag fluidity and mechanical strength.
Solution Approach 2:
The patent formulates a composite slag system combining iron oxides, zirconium, silicon, aluminum powders, slag-forming additives, and framework-forming additives. This composite slag composition achieves optimal balance between fluidity for burning front coverage and rapid solidification for stress resistance. The multi-component system creates a slag mass that simultaneously exhibits the necessary meltability to protect the burning front and the rapid solidification capability to withstand firing stresses, preventing munition failures.
4Reliability
If primer charge is additionally pressed onto the delay composition, then the ignition sensitivity can be improved, but the device complexity increases
Solution Approach 1:
The patent merges the primer charge and delay composition into a single integrated composite material system. The primer charge components (iron oxides, zirconium, boron) are combined with delay composition components (slag-forming additives, framework-forming additives, organic binders) in a unified formulation. This merging eliminates the need for separate primer and delay components, reducing structural complexity while maintaining high ignition sensitivity through the presence of sensitive metals like boron and zirconium in the integrated composition.
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 composition achieves controlled burning time and self-slagging properties, ensuring reliable operation under dynamic conditions and environmental safety, with improved ignition sensitivity and mechanical properties.
Implementation Method 1
The delay composition has at least one oxidizing agent and at least one reducing agent, especially slag-forming and framework-forming additives. The oxidizing agent comprises primary iron oxides having different oxidation states of the iron. As reducing agent, zirconium and zirconium hydride are primarily used.
Implementation Method 2
A number of delay compositions which are used for these purposes are known. Disadvantages of this thermite mixture are, inter alia, that due to the strongly exothermic reaction and the explosive burning it produces a very fluid slag
Implementation Method 3
It is known, for example from U.S. Pat. No. 7,883,593 B1, that mixtures of iron oxides and metal powders can be ignited and on burning produce liquid iron (known as thermites). A mixture having pulverulent iron oxide and zirconium can, for example compacted in tubes, easily be ignited, burns at a specific rate
Implementation Method 4
Framework-forming additives such as aluminosilicates and silicate glasses, and also a mineral binder. Aluminosilicates and silicate glasses are used as framework-forming additives, and these together with amorphous polysilicic acids bind the constituents of the charge.
Implementation Method 5
the burning front of the installed delay elements is open in certain types of munition due to their construction. The burning front is thus exposed directly to the stresses which occur during firing and during flight of the projects
Data Source
AI summary
A pyrotechnic delayed-action composition and primer charge made of REACh-compliant components that are safe for humans and the environment. The delayed-action composition comprises at least one oxidant, at least one reducing agent, at least one filler and at least one mineral binder. The performance parameters thereof, in particular the burning time, can be set variably within a wide range. The composition clinkers on its own, thus preventing extinction at the front of the burning material even in dynamic conditions. The primer charge comprises at least one oxidant, at least one reducing agent, at least one filler and at least one mineral binder. It is easy to ignite and, due to its clinker structure, transfers its energy well to the compositions to be ignited. The delayed-action composition and the primer charge have the same structure and can easily be combined and adapted to each other in delayed-action units.