Exploding Foil Igniter with Secondary Explosive and Barrier Isolation
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Solution Overview
Problem
Existing energetic material initiators for rocket motors are typically activated via low energy electric impulses and require alignment changes, which are costly, heavy, and unreliable, and often fail to meet high pressure and temperature sealing requirements post-firing, and some governmental agencies disapprove of the use of integrated switches in initiators.
Innovation Solution
An igniter assembly with a housing, initiator, input charge, first barrier, and output charge, where the input charge is a secondary explosive, the first barrier isolates the output charge from heat and pressure, and the output charge is a pyrotechnic material that combusts independently, allowing for in-line deployment and high pressure, high temperature impulse production without sympathetic initiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an initiator is constructed with an integrated planar switch for in-line deployment, then ease of operation and reliability are improved, but governmental approval may be compromised due to regulatory disapproval of switches in initiators
Solution Approach 1:
The patent removes the planar switch from the initiator assembly, extracting the problematic component that causes regulatory disapproval. The initiator is designed as a simple electrical component without switches, allowing in-line deployment while avoiding governmental approval issues.
Solution Approach 2:
The patent separates the initiator function from the switching function. The initiator is a standalone electrical component that can be deployed in-line, while the switching function is eliminated or placed outside the initiator assembly, resolving the conflict between in-line capability and regulatory approval.
2Ease of operation
If known initiators are used with alignment mechanisms to achieve in-line position, then ease of operation is improved, but device complexity, weight, and cost increase
Solution Approach 1:
Instead of using complex alignment mechanisms to move the initiator into position, the patent inverts the approach by designing the initiator to be inherently suitable for in-line deployment from the start. The initiator is constructed with its electrical inputs positioned for direct in-line installation, eliminating the need for alignment mechanisms.
Solution Approach 2:
The patent performs the alignment action in advance by designing the initiator with pre-positioned electrical inputs that are already in the correct orientation for in-line deployment. This preliminary configuration eliminates the need for complex alignment mechanisms during installation.
3Device complexity
If the output charge is not isolated from input charge heat and pressure, then device complexity is reduced, but the output charge may be sympathetically cooked-off or initiated
Solution Approach 1:
The patent divides the initiator into distinct functional zones: an input charge area and an output charge area, separated by physical barriers and spacing. This segmentation prevents thermal and pressure coupling between the input and output charges, eliminating sympathetic initiation while maintaining reasonable device complexity.
Solution Approach 2:
The patent introduces intermediate structures (barriers, spacing, and geometric configurations) that act as mediators between the input charge and output charge. These intermediaries block the transmission of heat and pressure waves, preventing sympathetic initiation without requiring direct contact or complex isolation systems.
4Power
If the initiator produces high pressure and temperature output, then productivity and power are improved, but sealing requirements post-firing become more difficult to meet
Solution Approach 1:
The patent segments the pressure and temperature generation into the input charge area, isolating the high-energy output from the electrical input interfaces. The output charge and its combustion products are confined to a separate zone, preventing excessive pressures and temperatures from compromising the sealing of electrical connections.
Solution Approach 2:
The patent uses intermediate barriers and geometric spacing as mediators that allow high power output while protecting sealed electrical interfaces. These intermediaries absorb and dissipate thermal and pressure effects before they reach the electrical input areas, maintaining sealing integrity.
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 solution enables a reliable, cost-effective, and in-line energetic material initiation system that can withstand high pressures and temperatures, eliminating the need for alignment changes and adhering to regulatory standards by isolating the output charge from input charge-generated heat and pressure, thus preventing premature initiation.
Implementation Method 1
The input charge can be formed of a secondary explosive and can be disposed adjacent the initiator
Implementation Method 2
The second barrier can be disposed on a side of the first barrier opposite the input charge and can combust in response to energy released during detonation of the input charge
Implementation Method 3
The output charge can be formed of a pyrotechnic material and can be disposed on a side of the second barrier opposite the first barrier. The output charge can combust in response to energy released during combustion of the second barrier
Implementation Method 4
The housing and the first barrier cooperate to form a structure that isolates the output charge from heat and pressure generated by the input charge if the input charge is cooked-off so that the output charge is not sympathetically cooked-off or initiated
Data Source
AI summary
An igniter assembly with a housing, an initiator, an input charge, a first barrier, a second barrier, and an output charge. The input charge is formed of a secondary explosive and disposed adjacent the initiator. The first barrier cooperates with the housing to form a chamber into which the input charge is received. The second barrier is disposed on a side of the first barrier opposite the input charge and combusts in response to energy released during detonation of the input charge. The output charge is formed of a pyrotechnic material and disposed on a side of the second barrier opposite the first barrier. The output charge can combust in response to energy released during combustion of the second barrier. The housing and the first barrier cooperate to isolate the output charge from heat and pressure generated by the input charge if the input charge is cooked-off.