Circuit Breaker Fluid Injection Arc Extinction
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Solution Overview
Problem
Conventional circuit breakers using compressed SF6 gas face limitations in increasing arc interruption performance without increasing size and cost, requiring complex pressure build-up mechanisms and high-pressure storage vessels due to the low critical temperature of SF6.
Innovation Solution
A circuit breaker design featuring an ejection device with a compartment containing a liquid arc-extinction medium that instantly evaporates in the injection zone, creating high blow pressure and improving arc extinction performance, without the need for external pressurization or complex mechanisms, using an organofluorine compound with a boiling point above -60°C for efficient vaporization and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressed SF6 gas is used as the interruption medium, then arc extinction performance can be achieved, but the device size and cost increase due to high-pressure storage vessels and complex pressure build-up mechanisms
Solution Approach 1:
The patent uses phase transition of the arc-extinction medium from liquid to gas form. The medium is stored in liquid form at ambient conditions and automatically vaporizes when arcing occurs, generating the required high pressure for arc extinction without complex compression mechanisms. This resolves the contradiction by eliminating the need for high-pressure storage vessels and complex pressure build-up mechanisms while maintaining reliable arc extinction performance.
Solution Approach 2:
The system employs self-service by utilizing the arc energy itself to vaporize the liquid medium and generate the required blow pressure. The arc heats the liquid arc-extinction medium, causing it to vaporize and expand, which automatically creates the high-pressure gas flow needed for arc extinction. This eliminates the need for external pressurization systems and reduces device complexity while ensuring reliable operation.
2Reliability
If SF6 is used as the arc-extinction medium, then effective arc interruption can be achieved, but the storage vessel requires extremely high pressure design due to the low critical temperature of SF6
Solution Approach 1:
The patent applies phase transition by storing the arc-extinction medium in liquid form at ambient temperature and pressure conditions, rather than requiring high-pressure gaseous storage. When arcing occurs, the liquid medium vaporizes and expands to the required pressure level. This approach eliminates the need for high-pressure storage vessel design while maintaining effective arc interruption capability through the phase change process.
3Reliability
If liquid arc-extinction medium is ejected to improve arc extinction, then high blow pressure can be generated, but complex ejection devices are required to build up sufficient pressure
Solution Approach 1:
The system uses self-service by allowing the arc energy to directly vaporize and pressurize the liquid arc-extinction medium in the injection zone. The liquid medium is simply positioned in the injection zone, and the arc automatically provides the energy needed for vaporization and pressure generation. This eliminates the need for complex ejection devices with external pressurization mechanisms while achieving high blow pressure for effective arc extinction.
Solution Approach 2:
The liquid arc-extinction medium acts as an intermediary that converts arc energy into high-pressure gas flow. The liquid medium absorbs arc energy, vaporizes, and expands to generate the required blow pressure. This intermediary approach simplifies the ejection device by using the medium itself as the pressure generation mechanism rather than requiring external compression systems.
4Force
If the ejection orifice opens into a high-pressure zone, then the liquid medium can be ejected with high blow pressure, but the counter-pressure increases making ejection difficult without external pressurization
Solution Approach 1:
The patent inverts the conventional approach by having the liquid medium vaporize in situ within the injection zone rather than being forced against counter-pressure. Instead of ejecting liquid against high counter-pressure, the liquid transforms to gas and expands outward, using the phase transition itself to overcome any counter-pressure. This inversion eliminates the need for external pressurization while achieving high blow pressure for arc extinction.
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 design achieves improved arc extinction and exhaust gas cooling performance with reduced size and cost, as the liquid medium vaporizes to generate high blow pressure and absorb arc energy, enhancing interruption capability and operational efficiency.
Implementation Method 1
the liquid medium vaporizes to generate high blow pressure
Implementation Method 2
the liquid medium vaporizes to generate high blow pressure and absorb arc energy
Data Source
AI summary
A circuit breaker including an ejection device with a compartment, in which an arc-extinction medium for improving circuit breaker operation is contained, and having an ejection orifice through which the arc-extinction medium is to be ejected, wherein the ejection orifice opens out into an injection zone of the circuit breaker in which the pressure is lower than in an arcing zone when an arc is present, and wherein the arc-extinction medium and/or exhaust-cooling medium is at least partially present in liquid form, when it is contained in the ejection device.