Ignition Unit Thermal Fuse Release Mechanism
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Solution Overview
Problem
Existing fire extinguishing aerosol devices face issues with igniter placement requiring high container temperatures for ignition, electrical connection reliability, and risk of fuse damage during shipment, leading to potential malfunction and safety concerns.
Innovation Solution
A spring-loaded ignition unit with a formed eutectic that deforms at a predetermined temperature to release a firing pin, which strikes a primer to ignite the pyrotechnic, allowing for thermal activation and mechanical engagement, and a modular design for easy assembly with a canister.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the igniter is positioned inside the housing, then the ignition can be achieved, but the container itself must reach a high temperature prior to ignition
Solution Approach 1:
The igniter is extracted from the internal housing and repositioned externally on the container surface. This allows the igniter to be activated by external heat sources (such as fire) without requiring the container interior to reach high temperatures, thereby resolving the contradiction between achieving ignition and avoiding excessive container temperature requirements
Solution Approach 2:
A heat-transfer medium (such as a metal plate or conductive material) is introduced between the external igniter and the pyrotechnic charge inside the container. This intermediary facilitates heat transfer from the externally positioned igniter to the internal pyrotechnic, enabling ignition without direct internal heating of the container
2Temperature
If a fuse is used to ignite the pyrotechnic, then the ignition can be achieved at high temperature, but the fuse is prone to damage and potential malfunction during shipment
Solution Approach 1:
The fuse is extracted from the internal housing and repositioned externally on the container. This external placement eliminates the risk of fuse damage during shipment while maintaining the high-temperature activation capability, as the external fuse can be triggered by fire or other high-temperature sources without being protected by the container
Solution Approach 2:
The fuse is pre-positioned externally in a location where it can be easily accessed and activated by fire or high-temperature sources during actual fire conditions, but remains isolated from shipment hazards. The external positioning allows the fuse to be ready for activation without being vulnerable to damage during transport
3Ease of operation
If electrical connections are used for the igniter, then the ignition can be controlled, but the detection devices and releasing panels increase cost and maintenance requirements
Solution Approach 1:
The electrical ignition system is replaced with a mechanical/thermal ignition system using an external fuse or igniter that can be activated by fire or high-temperature sources. This substitution eliminates the need for electrical connections, detection devices, and releasing panels, thereby reducing cost and maintenance requirements while maintaining ignition control through simple mechanical or thermal triggers
4Reliability
If the ignition unit is assembled separately from the canister, then the shipping safety is improved, but the assembly complexity increases
Solution Approach 1:
The ignition unit is segmented into separate components (igniter, fuse, housing) that can be independently packaged with the canister. This segmentation allows the components to be shipped separately for safety, then easily assembled at the point of use through simple mechanical connections (such as screw threads or snap-fits), thereby maintaining shipping safety while minimizing assembly complexity
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 ignition at lower temperatures, reduces maintenance costs, and ensures safe shipping by allowing assembly at the point of use, with a versatile ignition unit compatible with various canister sizes.
Implementation Method 1
a formed eutectic holds the restraining device in place such that when the eutectic deforms, the firing pin is released
Implementation Method 2
A spring is coupled to the firing pin, and a restraining device holds the pin in place in the housing
Implementation Method 3
the piston strikes a primer to ignite a desired pyrotechnic in the aerosol generating unit
Data Source
AI summary
An ignition unit for a fire extinguishing assembly has an ignition unit housing with a firing pin disposed within the housing. A spring is coupled to the firing pin, and a restraining device holds the pin in place in the housing. A formed eutectic holds the restraining device in place such that when the eutectic deforms, the firing pin is released and moved by the spring in a desired direction.