Pyrotechnic Delay Composition Using Tungsten and Trifer Tetraoxide
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Solution Overview
Problem
Current pyrotechnic delay compositions containing chromium-based compounds are toxic and pose regulatory challenges, while alternatives like iron oxide combinations can generate hot spots and require complex dosing, necessitating a non-toxic, reliable, and efficient delay composition for military and space applications.
Innovation Solution
A pyrotechnic delay composition using tungsten as a reducing agent combined with trifer tetraoxide and a second oxidant like potassium perchlorate, which has a higher oxygen content, to maintain consistent combustion speed and reliability, along with optional aluminum to adjust combustion speed, all within a tin or bismuth-based sheath.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chromium-based compounds (barium chromate) are used in pyrotechnic delay compositions, then the composition generates little gas and maintains reduced combustion speed in small diameter cords, but the toxicity of chromium leads to regulatory prohibition under European REACH directives
Solution Approach 1:
The patent changes the chemical composition parameters by replacing chromium-based oxidants (barium chromate) with alternative oxidants (potassium perchlorate, barium peroxide, bismuth oxide, or diiodine pentoxide) combined with tungsten as reducer. This substitution maintains the desired combustion characteristics while eliminating toxic chromium compounds, achieving compliance with REACH directives without sacrificing reliability
Solution Approach 2:
The patent creates a composite pyrotechnic composition combining tungsten (reducer) with selected oxidants (potassium perchlorate, barium peroxide, bismuth oxide, or diiodine pentoxide) and optional modifiers (aluminum, magnesium, iron powders). This composite approach achieves the desired combustion performance and gas generation characteristics while eliminating toxic chromium compounds
2Object-affected harmful factors
If iron oxide combinations are used to replace chromium-based compounds, then the composition becomes less toxic, but the composition generates hot spots and requires complex dosing of multiple components
Solution Approach 1:
The patent simplifies the composition by selecting specific oxidants (potassium perchlorate, barium peroxide, bismuth oxide, or diiodine pentoxide) with appropriate oxygen content to work effectively with tungsten reducer. This parameter optimization eliminates the need for complex multi-component formulations and delicate dosing required by iron oxide-based compositions, while maintaining low toxicity
Solution Approach 2:
The patent extracts and eliminates the problematic iron oxide component from the composition, replacing it with tungsten as the primary reducer. This removal of the problematic substance (iron oxide that causes hot spots) simplifies the formulation while maintaining the desired combustion characteristics and low toxicity profile
3Volume of moving object
If the cord diameter is reduced to less than 3mm, then the composition generates little gas and achieves compact form factor, but the combustion may stop or the cord may burst
Solution Approach 1:
The patent optimizes the composition parameters (oxidant/reducer ratio, particle size distribution, density) to ensure stable combustion in small diameter cords (less than 3mm). The selected oxidants and tungsten combination provides consistent combustion characteristics that prevent both combustion interruption and excessive gas generation, enabling reliable operation in compact cord formats
Solution Approach 2:
The patent tailors the composition characteristics locally adapted for small diameter application. The formulation is specifically designed to control gas generation and combustion rate in confined geometries, ensuring that the reaction zone maintains proper oxygen supply and heat distribution even in cords with external diameter less than 3mm
4Reliability
If a strong oxidant like barium chromate is used, then the combustion speed is controlled and reliable, but the composition becomes toxic and non-compliant with regulations
Solution Approach 1:
The patent changes the oxidant selection from toxic strong oxidants (barium chromate) to alternative oxidants (potassium perchlorate, barium peroxide, bismuth oxide, or diiodine pentoxide) with appropriate oxygen content. These alternatives provide sufficient oxidizing power for reliable combustion control while eliminating chromium toxicity, achieving compliance with REACH directives
Solution Approach 2:
The patent converts the harmful aspect (toxicity of chromium-based oxidants) into a benefit by selecting alternative oxidants that eliminate environmental and health hazards while maintaining or improving combustion performance. The alternative oxidants provide reliable combustion control without the toxic side effects, turning a regulatory constraint into an opportunity for improved composition safety
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 ensures reliable, non-toxic, and consistent combustion over a wide temperature range without interrupting the burning process, achieving combustion speeds of 2.64 mm/s to 4.0 mm/s in reduced diameters, compliant with environmental regulations.
Implementation Method 1
They ensure the triggering of a pyrotechnic event at the end of a determined time interval
Implementation Method 2
A pyrotechnic delay composition comprising at least one oxidant and at least one reducer, a composition which is characterized in that it comprises tungsten as first reducer, a first oxidant constituted by trifer tetraoxide and a second oxidant
Data Source
AI summary
The invention relates to a pyrotechnical retardant composition comprising at least one oxidant and at least one reductant. This composition is characterized in that it comprises tungsten as the first reductant, a first oxidant consisting of trifer tetroxide, and a second oxidant having an oxygen content higher than that of the first oxidant.