Vacuum Valve Holder Mechanism to Prevent Contact Misalignment
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Solution Overview
Problem
Conventional vacuum valves experience deterioration in voltage resistance performance due to axial misalignment and scratching of contacts during installation in vacuum circuit breakers, which affects the relative positions of fixed and moving contacts after voltage conditioning.
Innovation Solution
A vacuum valve design incorporating a holder mechanism that maintains the moving contact separated from the fixed contact during installation, using a retainer and pin to prevent contact and axial misalignment, and a bellows for maintaining vacuum while allowing movement, ensuring the vacuum valve's voltage resistance performance is preserved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the vacuum valve is moved after voltage conditioning before installation, then the vacuum valve can be installed in the vacuum circuit breaker, but the fixed contact and moving contact may be rubbed against each other causing scratches that deteriorate voltage resistance performance
Solution Approach 1:
A holder mechanism is introduced as an intermediary device that temporarily maintains the moving contact in a separated state from the fixed contact during installation operations. The holder acts as a mediator that prevents direct contact between the contacts while allowing the vacuum valve to be moved and installed, thus protecting the contacts from scratching while enabling installation operations.
2Reliability
If the moving contact is held separated from the fixed contact using a pin through the movable conductor, then contact scratching is prevented, but axial misalignment occurs during installation affecting relative positions of contacts
Solution Approach 1:
The holder mechanism is divided into separate components including a retainer and a pin, allowing the pin to be removed after installation. This segmentation enables the holder to serve its protective function during installation, then be disassembled to allow proper coupling of the movable conductor to the connecting rod without axial misalignment, thus resolving both contact protection and alignment precision requirements.
3Ease of manufacture
If the pin is removed from the movable conductor after installation, then the movable conductor can be coupled to the connecting rod, but axial misalignment between elements in the vacuum vessel occurs
Solution Approach 1:
The holder mechanism is designed to maintain axial alignment during the preliminary installation phase, and the pin is configured to be removed only after the vacuum valve is properly installed and aligned in the vacuum circuit breaker. This preliminary action ensures that axial alignment is preserved during the critical coupling operation between the movable conductor and connecting rod, preventing misalignment issues.
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 vacuum valve effectively suppresses deterioration of voltage resistance performance by maintaining the correct relative positions of contacts and preventing scratches, thus ensuring consistent performance post-installation.
Implementation Method 1
a vacuum vessel 3 in which a vacuum is produced
Implementation Method 2
application of a voltage between a fixed contact and a moving contact in the vacuum vessel causes dielectric breakdown originating from a micro-protrusion
Implementation Method 3
micro-protrusions are evaporated due to heat generated by electric discharge
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A vacuum valve (1) includes: a vacuum vessel (3); a cylinder (8); a partition wall (9) separating an inside of the vacuum vessel (3) from an inside of the cylinder (8); a movable conductor (7) penetrating the partition wall (9), the movable conductor (7) being movable in an axial direction in the vacuum vessel (3) and the cylinder (8); a fixed contact (4) fixed inside the vacuum vessel (3); a moving contact (5) integrated with the movable conductor (7), the moving contact (5) being capable of separating from the fixed contact (4) and coming into contact with the fixed contact (4) in association with movement of the movable conductor (7); a lid (10) that covers an end of the cylinder (8), the end being on a side opposite to the partition wall (9); a connecting rod (12) penetrating the lid (10) and coupled to the movable conductor (7) via an insulating rod (13) as an insulator; and a holder (16) that holds the connecting rod (12) while preventing movement of the connecting rod (12) toward the fixed contact (4) in a state where the moving contact (5) is separated from the fixed contact (4).