Insulating Fins in Pyrotechnic Disconnecting Device Cavity
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Solution Overview
Problem
Pyrotechnic cutting devices face limitations in maintaining reliable and complete electrical insulation, particularly due to high leakage currents and insufficient insulation resistance after activation, especially at higher voltages.
Innovation Solution
The cutting device incorporates a conductive element and a movable piston with a receiving cavity lined with electrically insulating material, featuring fins that increase the insulating surface area and dissipate plasma energy, along with additional cavities and channels to evacuate plasma and prevent electrical continuity between broken conductive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple cylindrical receiving cavity is used, then the device structure is simple, but the electrical insulation performance is insufficient with high leakage current
Solution Approach 1:
The receiving cavity is segmented by adding multiple fins extending from the internal wall, dividing the cavity space into multiple regions. This segmentation increases the effective insulating surface area and creates longer paths for potential arc discharge, thereby improving electrical insulation performance without requiring a complete redesign of the cavity structure
Solution Approach 2:
The fins extend radially from the internal wall into the receiving cavity, adding a radial dimension to the insulating structure. This transforms the insulating surface from a simple cylindrical wall to a multi-dimensional surface that includes both the original wall and the fin surfaces, significantly increasing the effective insulating area
2Reliability
If the piston diameter is increased to improve current cut-off, then the cut-off effectiveness is improved, but the receiving cavity volume must increase
Solution Approach 1:
The receiving cavity is divided into multiple regions by the fins, creating a more efficient use of space. This segmentation allows the cavity to accommodate the piston effectively while maintaining a compact overall volume, as the fins create additional insulating surfaces without requiring proportional increases in cavity volume
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 design ensures a high level of electrical insulation with minimal leakage current (10 mA at 2.5 kV) and resistance (greater than 80 MOhm), effectively maintaining a complete cut-off and reducing the risk of re-establishing current flow.
Implementation Method 1
an electric arc is produced for a short time. The plasma of the electric arc then deposits soot on the walls of the receiving cavity
Implementation Method 2
the plasma of the electric arc then deposits soot on the walls of the receiving cavity
Implementation Method 3
increase the effective surface area of insulating material allowing the dissipation of the energy of the plasma generated following the cutting of the conductive element
Data Source
Figure 1
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AI summary
The invention relates to a cutoff device comprising a conductive element (40) and a mobile piston (30), the piston (30) being able to move between a first position in which current flows in the conductive element (40) and a second position in which the current is cut off, the piston (30) being designed to break the conductive element (40) when it moves from its first position to its second position, the piston (30) being positioned in a reception cavity (12a) of a reception element (12) when said piston (30) is in its second position, the reception cavity (12a) being delimited by at least one internal wall (120) of the reception element (12), and the internal wall (120) being made of electrically insulating material. The reception element (12) furthermore comprises vanes (60) made of electrically insulating material and extending within the reception cavity (12a) from the at least one internal wall (120) of the reception element (12).