Dry Pyrotechnic Compaction for High-Density Gas Generators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing manufacturing processes for pyrotechnic objects, especially those with high charge content like ammonium perchlorate or sodium nitrate, face challenges such as material viscosity issues during extrusion and high investment costs due to lengthy drying steps and low productivity in granulation methods.
Innovation Solution
A dry process combining dry mixing and compaction of pulverulent raw materials like guanidine nitrate and basic copper nitrate, allowing for direct production of pellets, small tablets, granules, or compressed objects with high density, eliminating the need for solvent-based granulation and subsequent pelletizing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a twin-screw extruder is used for extrusion, then the manufacturing process is continuous and automated, but the material becomes too viscous to extrude when high charge content is used
Solution Approach 1:
The invention changes the physical state parameter of the pyrotechnic composition from a viscous semi-liquid state (suitable for extrusion) to a flowable powder state (suitable for high charge content). This is achieved by using a dry process with specific raw material selection and formulation, allowing the material to be processed as a free-flowing powder rather than a viscous mass, thus enabling both continuous manufacturing and high charge content (95% or more).
Solution Approach 2:
The invention uses a composite formulation of specific raw materials (oxidizing charges like ammonium perchlorate or sodium nitrate combined with reducing charges like metal hydrides or organic compounds) that maintains flowability even at high charge contents. The specific combination and ratio of these materials create a composite powder that can be processed continuously while achieving the desired high density and performance.
2Ease of operation
If a wet granulation process is used, then granules can be formed for appropriate flow, but the process becomes expensive and productivity is reduced due to lengthy drying steps
Solution Approach 1:
The invention extracts and eliminates the solvent-based granulation step entirely from the process. Instead of using water or other solvents to form granules and then drying them, the process directly uses a dry formulation approach where the pyrotechnic composition is processed as a free-flowing powder mixture. This removes the time-consuming drying step while still achieving the necessary flow properties through proper material selection and formulation.
Solution Approach 2:
The invention maintains continuous processing by eliminating the intermittent drying step required in wet granulation. The dry process allows for continuous feeding, mixing, and compaction of the pyrotechnic composition without interruption for solvent evaporation or drying cycles, thus maintaining high productivity while achieving the required flow characteristics through dry formulation techniques.
3Ease of manufacture
If conventional granulation methods are used, then granules can be produced for pelletizing, but the drying step is lengthy and difficult with high investment cost
Solution Approach 1:
The invention extracts and removes the complex drying infrastructure and processes from the manufacturing system. By using a dry formulation approach with specifically selected raw materials that maintain flowability without solvents, the process eliminates the need for dryers, evaporators, and associated heating systems, thereby reducing device complexity and investment costs while still achieving proper granule formation for pelletizing.
Solution Approach 2:
The invention replaces expensive, complex drying equipment and lengthy drying processes with a simpler, more direct dry formulation approach. The process uses straightforward mixing and compaction operations that can be performed with simpler, more affordable equipment, reducing the overall investment cost while achieving the same functional outcome of forming processable granules.
4Reliability
If high charge content compositions are used, then pyrotechnic performance is enhanced, but the material viscosity increases and extrusion becomes impossible
Solution Approach 1:
The invention changes the physical state and flow characteristics parameters of the pyrotechnic composition to enable processing at high charge contents. By formulating the composition as a dry, free-flowing powder mixture with specific raw material selections, the material maintains processability and flowability even at 95% or higher charge content, thus achieving both high performance and ease of manufacture.
Solution Approach 2:
The invention uses a composite formulation strategy where specific oxidizing charges (ammonium perchlorate, sodium nitrate) are combined with carefully selected reducing charges (metal hydrides, organic compounds) in optimized ratios. This composite approach ensures that the high charge content composition maintains appropriate flow characteristics and processability, enabling continuous manufacturing while achieving the desired pyrotechnic performance.
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 approach enhances productivity and reduces production costs by enabling the direct production of high-performance pyrotechnic objects with excellent flow properties for use in motor vehicle safety applications, such as gas generators, while maintaining high density and theoretical density percentages.
Implementation Method 1
dry compaction of the mixture obtained
Implementation Method 2
compaction of the mixture obtained
Data Source
AI summary
The present invention relates to a dry process for the manufacture of pyrotechnic objects from at least one reducing charge selected from guanidine derivatives, metal hydrides, alkali metal hydrides and alkaline earth metal hydrides, and at least one oxidizing charge selected from alkali metal nitrates, alkaline earth metal nitrates and basic metal nitrates, at least one of said reducing and oxidizing charges having the property of flowing under stress. Said process makes it possible to obtain pellets and small tablets directly by compaction/compression, to obtain granules, usable as such, by compaction and then granulation, and to obtain compressed objects by compaction, granulation and then compression.The high-performance pyrotechnic objects obtained constitute a further subject of the invention.