Gas Generant Grains via Spray Drying for High Burn Rates
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Solution Overview
Problem
Current pyrotechnic gas-generating compositions for inflatable restraint systems, such as airbag inflators, face challenges in achieving high burning rates and gas yields without using expensive ingredients like tetrazoles, while ensuring safety and cost-effectiveness, and require innovative fabrication methods to meet advanced application requirements.
Innovation Solution
A method involving the formation of an aqueous mixture of guanidine nitrate, basic copper nitrate, and potassium perchlorate, followed by spray drying and pressing to produce gas generant grains, which includes optional additives like metal oxides and slag promoters, enhancing burning rates and gas yields without resorting to expensive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If expensive ingredients such as tetrazoles and bitetrazoles are used to increase burning rate and gas yield, then gas generant performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive tetrazole and bitetrazole compounds with a more economical composition based on guanidine nitrate, basic copper nitrate, and potassium perchlorate. This substitution maintains the required burning rate performance while significantly reducing raw material costs, directly addressing the contradiction between performance and manufacturing cost
Solution Approach 2:
The patent optimizes the composition ratios and particle size distribution of the gas generant components to achieve high burning rates without expensive additives. By carefully controlling the parameters of the aqueous mixture and spray drying process, the invention achieves performance comparable to expensive compositions at lower cost
2Productivity
If finely ground particles are admixed and pelletized to improve gas yield and burning rate, then gas generant performance is improved, but fabrication process complexity increases
Solution Approach 1:
The patent combines multiple fabrication steps into a single integrated spray drying process. The aqueous mixture of guanidine nitrate, basic copper nitrate, and potassium perchlorate is spray dried to directly form the final grain structure, eliminating the need for separate admixing, pelletizing, and shaping operations while maintaining high gas yield and burning rate performance
Solution Approach 2:
The patent replaces complex mechanical pelletizing and grain-forming equipment with a spray drying system. This substitution simplifies the fabrication process by using fluid dynamics and phase change rather than mechanical processing to achieve the desired grain morphology and performance characteristics
3Productivity
If traditional pyrotechnic compositions are used to ensure safety during handling and storage, then safety is maintained, but burning rate and gas yield are insufficient for advanced applications
Solution Approach 1:
The patent creates a composite pyrotechnic composition combining guanidine nitrate (fuel), basic copper nitrate (oxidizer), and potassium perchlorate (secondary oxidizer). This composite material achieves high burning rates and gas yields suitable for advanced inflator applications while maintaining the safety characteristics of traditional compositions during handling and storage
Data Source
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AI summary
Compositions and methods relating to gas generants used in inflatable restraint systems. The gas generant grains formed via spray drying techniques of the present disclosure provide superior performance, including high burn rates and high gas yields. Further, processing of the gas generant grain products can be streamlined. Such gas generants include by way of non-limiting example, guanidine nitrate, basic copper nitrate, and a secondary oxidizer, such as potassium perchlorate.