Weld-Sealed Pyrotechnic Gas Generator for Hermetic Leak Control
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Solution Overview
Problem
The manufacturing of purely pyrotechnic gas generators is hindered by the increased time and cost associated with gluing on tampings for sealing, requiring specific pressing devices and large adhesive surfaces, and the need to avoid heat impacts from welding seams.
Innovation Solution
A gas generator with a hermetically sealed housing formed exclusively from metal components welded together, using weld seams to seal diffusion paths, and a method for leak testing with a small amount of helium to ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glued-on tampings are used to seal discharge openings, then sealing of diffusion paths is achieved, but manufacturing time and cost increase due to required pressing devices and procedures
Solution Approach 1:
The patent replaces the mechanical gluing system with a welding system. Instead of using adhesive materials and pressing devices to seal the combustion chamber, the invention uses weld seams to create a permanent, reliable seal. This substitution eliminates the need for complex gluing procedures and pressing devices, thereby improving manufacturing efficiency while maintaining sealing reliability.
Solution Approach 2:
The patent changes the sealing method from chemical adhesion (gluing) to thermal bonding (welding). By changing the fundamental parameter of how the tamping is attached to the housing, the invention achieves both reliable sealing and simplified manufacturing. The welding process creates a stronger, more permanent bond compared to adhesive methods.
2Reliability
If large adhesive surfaces are provided for tamping gluing, then adequate adhesion is ensured, but device complexity and manufacturing space requirements increase
Solution Approach 1:
The welding process replaces the adhesive system entirely, eliminating the need for large adhesive surfaces. The weld seam creates a reliable seal through direct metallurgical bonding between the tamping and the housing, without requiring extensive surface area for adhesion. This simplifies the manufacturing process and reduces device complexity.
3Reliability
If distance is observed from welding seams to tamping, then heat impact on adhesive layer is avoided, but compactness and efficiency are reduced
Solution Approach 1:
Instead of protecting the adhesive layer from heat by maintaining distance, the invention inverts the approach by eliminating the adhesive layer entirely and using welding directly on the tamping. This allows the weld seam to be placed immediately adjacent to or even on the tamping itself, achieving maximum compactness without compromising sealing reliability.
4Reliability
If specific pressing devices and procedures are used for tamping gluing, then proper sealing is achieved, but manufacturing cost and time expenditure increase
Solution Approach 1:
The patent replaces the complex gluing system with a simpler welding system. Welding equipment and procedures are generally more straightforward and require fewer specialized fixtures compared to precision gluing operations. The welding process naturally provides reliable sealing without requiring the same level of procedural complexity as adhesive application and curing.
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
This approach reduces manufacturing complexity and cost by eliminating the need for large adhesive surfaces and heat-avoidance distances, allowing for a more compact and efficient design while ensuring reliable sealing and leak detection.
Implementation Method 1
each possible diffusion path out of the interior of the housing to the environment of the gas generator is sealed by means of a weld seam
Implementation Method 2
a method for leak testing with a small amount of helium to ensure reliability
Data Source
AI summary
The present disclosure relates to a gas generator comprising a housing, an igniter and a pyrotechnic charge via which gas for filling a gasbag can be provided, wherein the gas generator is free from stored pressurized gas in the idle state, characterized in that each possible diffusion path out of the internal chamber of the housing is sealed relative to the environment of the gas generator by means of a weld seam. The present disclosure also relates to a method for leak testing a pyrotechnic gas generator of this type, wherein, before the gas generator is welded against diffusion, a test amount of helium is introduced into the housing and, in a subsequent leak testing step, a measurement is carried out to determine whether helium is passing out of the housing.