Combustion Igniter Cord With Concentric Sheath for High-Power Ignition
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Solution Overview
Problem
Conventional igniter cords have limited energy and power to ignite new generations of propellant powders, and increasing the pyrotechnic composition in the cord decreases combustion speed and power.
Innovation Solution
A combustion igniter cord design with a core surrounded by two concentric cylindrical tubes, one of which is filled with propellant powder, to increase energy delivery while maintaining ignition speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the quantity of pyrotechnic composition in the igniter cord is increased to provide more energy, then the ignition energy is improved, but the combustion speed decreases and power is reduced
Solution Approach 1:
The igniter cord is segmented into an inner core containing the pyrotechnic composition and an outer sheath containing the propellant powder. This segmentation allows the core to control ignition propagation speed while the sheath provides additional energy, resolving the contradiction between energy output and combustion speed.
Solution Approach 2:
The inner core is nested within the outer sheath, creating a concentric structure where the pyrotechnic core initiates combustion that then propagates through the propellant powder sheath. This nested configuration enables the smaller core to control timing while the larger sheath delivers increased energy.
2Use of energy by moving object
If the quantity of pyrotechnic composition in the igniter cord is increased to provide more energy, then the ignition energy is improved, but the power is reduced due to decreased combustion speed
Solution Approach 1:
By segmenting the igniter cord into functional zones (core for speed control, sheath for energy delivery), the system achieves both high energy and high power simultaneously, as the core's fast combustion initiates the sheath's high-energy release without the sheath's mass slowing down the overall power delivery.
Solution Approach 2:
Different regions of the igniter cord have different properties: the inner core has fast-burning characteristics for speed control, while the outer sheath has high-energy-density propellant for energy delivery. This local differentiation allows the system to optimize both power and energy independently.
3Device complexity
If conventional axial ignitor tubes are used, then the structure is simple, but they cannot be incorporated with deep-penetrating arrow projectiles
Solution Approach 1:
The igniter system is segmented into a flexible cord that can be routed along the projectile shaft and a separate axial ignitor tube at the base. This allows the main body to remain simple while adapting to deep-penetrating projectile configurations through flexible routing.
Solution Approach 2:
The igniter cord transitions from a purely axial arrangement to a multi-dimensional configuration that can follow the projectile shaft contour and connect to the base ignitor tube, enabling compatibility with deep-penetrating projectiles while maintaining structural simplicity.
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 new design provides 100 to 1000% increase in ignition power and maintains similar operating time, effectively igniting new propellant powders.
Implementation Method 1
Igniter cords, in combustion and not in detonation, usually comprise a plastic tube containing a pyrotechnic composition such as black powder
Implementation Method 2
The relay is used to significantly increase the energy delivered... filled the interstices thereby generated by the energetic material serving as a relay, e.g. powder of medium caliber
Data Source
AI summary
A Combustion igniter cord with enhanced power. Combustion igniter cord for a propellant charge contained in the case of a cartridge, said igniter cord consisting of a core comprising a pyrotechnic material and surrounded by a sheath. The sheath consists of two concentric cylindrical tubes between which is arranged a free powder energetic material. Both tubes are made of an inert polymer material or contain an extruded energetic propellant powder material or one tube may be made of an inert polymer material and the other may contain an extruded energetic propellant powder material.