Insulator Venting Structure for Arc-Induced Overpressure Relief
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Solution Overview
Problem
High voltage electrical devices in railway vehicles, such as sensors and circuit breakers, face the risk of explosion due to electric arcs forming within insulators, which can be exacerbated by material defects or overvoltage, leading to potential injury from flying fragments and degradation from external conditions like humidity and pollutants.
Innovation Solution
The integration of a safety ring made of metallic material with alternating thin and reinforced parts, designed to rupture and allow gas escape in case of overpressure, combined with an insulator envelope of flexible silicone elastomer and a conductive base for earth connection, minimizes the risk of explosion and protects against external damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diaphragm is used to rupture in case of overpressure, then gas escape is enabled and explosion is prevented, but the diaphragm can deteriorate under external conditions like humidity and pollutants, causing puncturing during normal operation
Solution Approach 1:
The patent introduces an intermediary protective structure (the insulator envelope with integrated rupture disc) that mediates between the harmful internal pressure and the external environment. The rupture disc is protected by the envelope until activation, preventing premature deterioration from humidity and pollutants while enabling gas escape when needed.
Solution Approach 2:
The rupture disc is designed as a disposable safety component that is intentionally made vulnerable to rupture under overpressure conditions. It serves its purpose once (when pressure exceeds threshold) and is replaced if needed, providing reliable explosion prevention without requiring long-term durability against environmental factors.
2Strength
If the insulator material is made rigid to maintain structural integrity, then mechanical strength is improved, but the insulator may explode with flying fragments when overpressurized
Solution Approach 1:
The insulator is segmented into a rigid structural body and a separate rupture disc component. The rigid body maintains structural integrity for normal operation, while the rupture disc segment is designed to fail controllably under overpressure, preventing the entire insulator from exploding and generating flying fragments.
Solution Approach 2:
The patent employs a thin rupture disc film within the insulator structure that can flex and rupture under overpressure conditions. This thin film approach allows controlled pressure release without the catastrophic failure of the entire rigid insulator structure, eliminating flying fragments while maintaining normal structural strength.
3Stability of the object's composition
If the insulator envelope is made of flexible material to allow gas expansion, then pressure release capability is improved, but the envelope may allow moisture and impurities to enter the device
Solution Approach 1:
The envelope acts as an intermediary barrier that provides a controlled interface between the internal insulator cavity and the external environment. It allows managed pressure expansion while maintaining protection against moisture and impurities, except when the rupture disc intentionally fails to release pressure.
Solution Approach 2:
The flexible envelope shell accommodates pressure changes through elastic deformation rather than requiring open structures. This flexibility allows gas expansion space while the continuous shell material blocks moisture and impurities from entering, unless the rupture disc activates to create a controlled opening.
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 configuration effectively prevents uncontrolled explosions by allowing gas release while maintaining structural integrity and preventing moisture and impurities from entering the device, reducing the risk of injury and operational degradation.
Implementation Method 1
a safety device arranged to evacuate gas overpressures
Implementation Method 2
an electric arc can form inside the device, burning or vaporizing the materials on its passage. This produces gases which are heated by the arc
Implementation Method 3
allowing moisture and impurities to enter into it which could degrade its operation
Data Source
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AI summary
The high-voltage electrical device according to the invention, for example a voltage sensor (10) or a circuit breaker, comprises an insulator (12), an electrical device (13) isolated by the insulator (12), and a safety device (23) for venting overpressure of gas from the device upon the formation of an electric arc. The insulator (12) comprises a hollow body (18) in which the electrical device (13) is located and an enclosure (19) that covers the hollow body (18). The enclosure (19) is made of a more flexible material than that of the hollow body (18). The safety device (23) is located in the insulator (12) opposite the enclosure (19) and is arranged to allow the overpressure of gas to locally open the enclosure (19) in order to prevent an uncontrolled explosion of the device.