Rock Cracker Cartridge Deflagration Ignition Safety
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Solution Overview
Problem
Existing rock cracker cartridges require detonating explosives for ignition, which poses safety risks during transportation and handling, and existing ignition systems do not meet the lowest Swedish classification for explosive transportation (class 1.4).
Innovation Solution
A rock cracker cartridge with an integrated ignition assembly that uses a non-explosive ignition capsule with an electrical igniter and deflagration combustion, housed within a thin-walled plastic sleeve with strength-reducing grooves, to ensure controlled explosion within a closed space, avoiding detonation and minimizing fragmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional detonating explosives are used for ignition, then reliable ignition of the rock cracker cartridge is achieved, but safety risks during transportation and handling increase
Solution Approach 1:
The invention extracts the detonating explosive from the ignition system, replacing it with a deflagration-based ignition capsule. The ignition capsule contains only deflagrating composition and an electrical igniter, eliminating the need for detonating explosives while maintaining reliable ignition of the main charge.
Solution Approach 2:
The invention introduces a deflagrating composition as an intermediary between the electrical igniter and the main explosive charge. This intermediary substance burns with deflagration rather than detonating, providing a safe transition that initiates the main charge without requiring detonating explosives in the ignition system.
2Object-affected harmful factors
If a thin-walled plastic sleeve is used for the ignition assembly, then transportation safety is improved, but structural strength is reduced
Solution Approach 1:
The plastic sleeve incorporates localized weakness features in the form of circumferential grooves at specific locations. These grooves create controlled points of weakness that allow the sleeve to rupture in a predictable manner during deflagration, rather than requiring the entire sleeve to withstand high pressures. The sleeve maintains sufficient strength in non-grooved areas while having predetermined failure points.
3Device complexity
If an integrated ignition assembly is used, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The invention merges the ignition capsule, electrical igniter, and plastic sleeve into a single integrated ignition assembly that is pre-assembled as one unit. This integrated assembly is then inserted as a single component into the rock cracker cartridge, simplifying the overall device while requiring precise manufacturing of the integrated unit itself.
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 allows for safe transportation and handling of the rock cracker cartridge while effectively cracking boulders or rock sections without fragmenting them into hazardous pieces, meeting the lowest Swedish classification for explosive transportation and achieving controlled deflagration combustion.
Implementation Method 1
uses a non-explosive ignition capsule with an electrical igniter and deflagration combustion
Implementation Method 2
deflagration combustion
Implementation Method 3
thin-walled plastic sleeve with strength-reducing grooves
Data Source
Figure 1~4
Figure 5~7
Figure 8~9
AI summary
A rock cracker cartridge (1) contains a cracking powder charge (6) and an ignition capsule (30) with an ignition powder charge (29) in an ignition unit sleeve (31) which does not possess the mechanical strength that would be required for the ignition powder charge to be exploded in the open air when ignited. In the rock cracker cartridge there is also provided an ignition assembly sleeve (7a) which surrounds the ignition unit sleeve when the rock cracker cartridge is primed. In combination, the assembly which surrounds the cracking powder charge, and which comprises the ignition unit sleeve and the ignition assembly sleeve, has a sufficient strength for an adequate pressure to be developed in the assembly such that the ignition powder charge will explode and generate a flame of fire and the ignition unit sleeve as well as the ignition assembly sleeve be penetrated by the pressure and the flame of fire, said flame offire igniting the cracking powder charge.