Silicon Transfer Charge Carrier for Safe and Arm Explosive Train
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Solution Overview
Problem
Manufacturing pyrotechnic charges for miniaturized safe and arm (S&A) devices, such as MEMS-type systems, is challenging due to small dimensions and small quantities of materials involved, requiring innovative methods for filling high explosives into very small cavities.
Innovation Solution
A mechanical control system using a rotatable or slidable silicon-based transfer charge carrier with a porous explosive passage (EPP) that can be aligned or non-aligned with input and output charges to interrupt or enable the detonation train, allowing the S&A device to switch between safe and armed states, utilizing porous silicon impregnated with an oxidizer and fabricated using MEMS techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional filling methods (wipe loading, pressure loading, syringe loading) are used for miniaturized S&A devices, then the explosive material can be loaded into small cavities, but the manufacturing complexity and difficulty increase significantly due to small dimensions and material quantities
Solution Approach 1:
The patent employs a porous transfer charge assembly that can be impregnated with explosive material. The porous structure allows explosive slurry to be drawn into the transfer charge through capillary action, eliminating the need for complex precision filling operations. The porous material provides high surface area and interconnected pores that facilitate uniform explosive distribution throughout the transfer charge volume.
Solution Approach 2:
The patent replaces manual precision filling operations with a chemical/physical impregnation process. Instead of mechanically forcing explosive material into small cavities using syringes or pressure loading, the system uses slurry preparation followed by capillary impregnation, where the explosive solution naturally penetrates the porous transfer charge structure without requiring precision mechanical control.
2Reliability
If the transfer charge assembly is made inert to interrupt the detonation train in safe state, then safety is improved, but the device complexity increases due to the need for mechanical movement mechanisms
Solution Approach 1:
The transfer charge assembly is designed as a dynamic component that can change its physical state between inert (safe) and conductive (armed) configurations. The assembly includes a movable element such as a rotor or slider that physically blocks or uncovers the explosive passage, enabling transition between safe and armed states through controlled mechanical movement.
Solution Approach 2:
The patent separates the detonation path into distinct segments with the transfer charge assembly acting as a controllable gate. In the safe state, the transfer charge is positioned to extract or block the detonation path, physically disconnecting the input charge from the output charge. This creates an inherent safety barrier that requires active movement to overcome for arming.
3Ease of manufacture
If volatile mobile phase is added to slurry to dissolve energetic material, then explosive material can be loaded into small cavities, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The explosive slurry is prepared in advance with the volatile mobile phase and energetic material dissolved or suspended together. The porous transfer charge assembly is also prepared beforehand with its porous structure formed. During assembly, the pre-prepared slurry is applied to the porous transfer charge, and the volatile phase naturally evaporates, leaving the explosive material impregnated in the porous structure without requiring additional processing steps.
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
Enables reliable and controlled switching between safe and armed states in S&A devices, preventing unintentional activation by mechanically controlling the detonation train, compatible with MEMS fabrication methods and suitable for miniaturized systems.
Implementation Method 1
A transfer charge carrier (TCC) is produced, for example by employing the photo-lithography mask and etch techniques familiar to those in the semiconductor fabrication technology to form micro-miniature parts of silicon or other materials
Implementation Method 2
A mechanical control system using a rotatable or slidable silicon-based transfer charge carrier with a porous explosive passage (EPP) that can be aligned or non-aligned with input and output charges
Implementation Method 3
utilizing porous silicon impregnated with an oxidizer and fabricated using MEMS techniques
Data Source
AI summary
A Safe-and-Arm system for the prevention of unintentional operation of an explosive device by interrupting a detonation train, the system employing an interruptive transfer assembly made of silicon and suitable for implementing in a MEMS device, the assembly including a silicon based transfer charge carrier on a porous explosive passageway made by etching, the passageway extending between at least two ports on the circumference of the transfer assembly, and a drive means that can mechanically bring about at least one armed state of a detonation train.