Arc-Extinguishing Chamber Pressure Control for Bellows Durability
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Solution Overview
Problem
The durability of the bellows in vacuum circuit breakers is compromised by significant pressure differentials between the air pressure inside the vacuum container and the bellows, leading to excessive central bulging and reduced lifespan.
Innovation Solution
The arc extinguishing chamber maintains atmospheric pressure within a sealed space surrounded by the bellows, contact case, and movable-side support in the open state, and less than atmospheric pressure in the closed state, minimizing pressure differentials and reducing central bulging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the air pressure inside the bellows is constantly atmospheric pressure, then the bellows can extend and contract freely, but the central bulging increases and durability decreases
Solution Approach 1:
The patent applies dynamics by making the air pressure inside the bellows variable rather than constant. The bellows internal pressure dynamically adjusts between atmospheric pressure (open state) and vacuum pressure (closed state), allowing the system to optimize both operational freedom and structural durability at different moments in the switching cycle.
Solution Approach 2:
The patent changes the physical parameter of air pressure inside the bellows based on the operational state. By transitioning the pressure parameter from atmospheric to vacuum and vice versa, the system reduces the pressure differential across the bellows wall during critical phases, minimizing central bulging while maintaining operational functionality.
2Reliability
If the air pressure difference between inside and outside the vacuum container is large, then the vacuum sealing is effective, but the bellows experiences excessive central bulging
Solution Approach 1:
The patent introduces the movable lead as an intermediary element that transmits force from the external actuating mechanism to the movable contact point inside the vacuum container. This allows the bellows to remain relatively stationary while still achieving contact point movement, reducing the mechanical stress and central bulging on the bellows structure.
Solution Approach 2:
The system dynamically adjusts the bellows pressure state based on operational requirements. During vacuum maintenance phases, the bellows remains under vacuum for effective sealing. During switching operations, the bellows pressure equalizes to reduce differential stress, preventing excessive central bulging while maintaining vacuum integrity when needed.
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 enhances the durability of the bellows by reducing the frequency and extent of central bulging, thereby extending its lifespan and improving the overall performance of the vacuum circuit breaker.
Implementation Method 1
An air pressure inside a closed space surrounded and sealed by the bellows, the contact case, and the movable-side support is atmospheric pressure in the open state, and is less than atmospheric pressure in the closed state
Data Source
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AI summary
An arc extinguishing chamber (23) includes: a vacuum interrupter (4) including a bellows (25); a contact case (8) having a tubular shape and made of a conductive material; a contact (33) fixed to an end of a movable lead (11), disposed inside a tube of the contact case (8), and electrically connecting the contact case (8) and the movable lead (11) to each other; a seal rod (14) that is connected to the movable lead (11) and moves the movable lead (11); and a movable-side support (7) having a cylinder shape with a bottom surface in which a hole through which the seal rod (14) passes is formed. An air pressure inside a closed space surrounded and sealed by the bellows (25), the contact case (8), and the movable-side support (7) is atmospheric pressure in an open state, and is less than atmospheric pressure in a closed state.