Monolithic Pyrotechnic Gas Generator Blocks
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Solution Overview
Problem
Current gas pressurization systems for emergency and rescue devices, such as fire extinguishers and inflatable structures, rely on high-pressure neutral gases, which require large, heavy storage tanks and frequent maintenance, posing challenges in weight, dimensioning, and operational costs, especially in the aeronautics sector.
Innovation Solution
Development of monolithic pyrotechnic gas generator blocks with specific size, porosity, and composition, comprising guanidine nitrate, basic copper nitrate, and inorganic titanates, that produce a moderate flow rate of combustion gas over a long duration, replacing high-pressure gases and reducing system weight and maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If high-pressure neutral gas is used for pressurization, then the gas can be stored in a compact tank, but the tank requires thick walls or light composite materials leading to significant weight and high manufacturing costs
Solution Approach 1:
The invention changes the pressure parameter from high-pressure storage (200-400 bars) to atmospheric pressure pyrotechnic generation, eliminating the need for thick-walled tanks while maintaining the same gas delivery function
Solution Approach 2:
The invention replaces the mechanical high-pressure storage system with a pyrotechnic chemical system that generates gas on-demand, substituting mechanical pressure containment with chemical energy conversion
2Speed
If high-pressure gas storage is used, then gas can be delivered immediately, but periodic maintenance operations are necessary to guarantee optimal and secure operation, impacting operating costs
Solution Approach 1:
The invention uses disposable pyrotechnic blocks that are replaced rather than maintained, eliminating periodic maintenance operations while ensuring reliable gas generation for the device's operational life
Solution Approach 2:
The pyrotechnic blocks are pre-prepared with optimal composition and geometry to ensure complete, reliable combustion and gas generation, eliminating the need for operational maintenance
3Duration of action of stationary object
If pyrotechnic objects with balanced oxygen balance are used, then gas can be generated over a relatively long period, but the combustion temperature and combustion speed are too high with reference to specifications
Solution Approach 1:
The invention changes the oxygen balance parameter from balanced (close to zero) to strongly unbalanced (≥ -20%), which reduces combustion temperature and speed while maintaining long-duration gas generation through controlled porosity and geometry
Solution Approach 2:
The invention creates local quality variations within the pyrotechnic block through controlled porosity distribution and geometry, allowing different regions to burn at different rates and temperatures to achieve overall controlled combustion
4Speed
If low porosity is used in pyrotechnic blocks, then combustion speed increases, but the gas generation duration decreases
Solution Approach 1:
The invention optimizes the porosity parameter to a specific range (3-15%) that balances combustion speed and duration, and uses geometry parameters (thickness ≥ 10 mm, diameter ≥ 10 mm) to control the burn rate and extend gas generation time
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 monolithic pyrotechnic blocks efficiently generate gas over extended periods, achieving low combustion temperatures and speeds, reducing the size and weight of gas generators, and eliminating the need for frequent maintenance, while maintaining effective pressurization of structures.
Implementation Method 1
the monolithic pyrotechnic blocks of the invention, due to their intrinsic characteristics of size, porosity and composition, are particularly efficient... with reference to their (low) combustion speed and temperature
Implementation Method 2
composition, free of binder, contains nitrate of guanidine (NG: as a reducing charge) and basic copper nitrate (BCN: as an oxidizing charge)
Implementation Method 3
said blocks being adapted to be integrated into devices dedicated to the pressurization of structures... durations of at most a few milliseconds and even gas generators for hood lift cylinders (durations of around 100 milliseconds)
Data Source
Figure 1
AI summary
The present invention relates mainly to substantially cylindrical gas-generating pyrotechnical monolithic blocks, characterised by having: a thickness no lower than 10 mm, an equivalent diameter no lower than 10 mm, and a porosity lower than 5%; and a composition, given as weight percentages, which contains, for at least 94% of the weight thereof: + 77.5% to 92.5% of guanidine nitrate, + 5% to 10% of basic copper nitrate, and + 2.5% to 12.5% of at least one inorganic titanate with a melting temperature higher than 2100 K. Said blocks are particularly efficient, in particular as regards their combustion temperature and speed (low), the ease with which they can be obtained, and their gas yield.