Exhaust Diffuser Helicoidal Flow for Gas-Insulated Circuit Breakers
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Solution Overview
Problem
Existing gas-insulated high-voltage circuit breakers face challenges with exhaust diffusers that require large metal outer tanks, inefficient gas mixing, and unsatisfactory purging of current-breaking gases due to long exhaust paths, constriction elements, and trapped gas pockets.
Innovation Solution
A gas exhaust diffuser design featuring a first casing with radial openings and incurved elements that create a helicoidally-shaped exhaust flow path, redirecting and mixing hot gases effectively within a compact structure, utilizing the available volume more efficiently and reducing the length of the diffuser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a longitudinal exhaust path with deflections is used to extend the exhaust path, then the hot gases can be cooled more effectively, but the radial dimensions of the exhaust diffuser and outer tank increase
Solution Approach 1:
The patent transforms the exhaust path from a longitudinal configuration (extending along the axis) to a radial configuration (extending outward from the center). The incurved elements positioned at radial openings create a helicoidal flow path that utilizes the radial dimension of the second casing, thereby achieving extended cooling path without increasing radial dimensions of the overall diffuser structure.
Solution Approach 2:
The incurved elements (blades) positioned at the radial openings create a curved, helicoidal flow path for the exhaust gases. This curvature allows the gas to follow a spiral trajectory through the second casing, effectively lengthening the cooling path while maintaining a compact radial footprint.
2Temperature
If constriction elements are placed along the longitudinal path to slow the hot gas stream, then the gases can be cooled before exiting, but the purging of current-breaking gases between the arcing contacts is hindered
Solution Approach 1:
The exhaust diffuser is divided into two functional sections: the first casing (exhaust containment volume) dedicated to rapid purging of hot gases from the arcing region, and the second casing (cooling volume) dedicated to cooling the gases. The radial openings with incurved elements serve as the interface between these sections, allowing segmented functional optimization without compromise.
Solution Approach 2:
The patent moves the cooling function from the longitudinal path (where it would interfere with purging) to the radial dimension. The helicoidal flow path in the second casing allows cooling to occur in a separate spatial domain, eliminating the conflict between rapid purging and effective cooling.
3Reliability
If a long gap is maintained between the evacuation crown and the metal outer tank for dielectric insulation, then insulation is achieved, but the metal outer tank becomes very large
Solution Approach 1:
The exhaust diffuser structure, particularly the second casing with its outlets, serves as an intermediary element between the hot gas evacuation path and the metal outer tank. This intermediary structure allows for optimized insulation spacing and configuration, achieving dielectric insulation requirements while minimizing the overall tank 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
The solution enables effective cooling and purging of hot gases while minimizing the overall dimensions of the exhaust diffuser and the metal outer tank, optimizing space usage and improving gas containment in high-voltage circuit breakers.
Implementation Method 1
a plurality of incurved elements (preferably blades) are positioned radially in the second casing at the at least one radial opening to create a rotation of an entering exhaust flow in a plane perpendicular to the principal axis, thereby generating a substantially helicoidally-shaped exhaust flow path in the second casing
Implementation Method 2
an exhaust diffuser connected to the arcing volume for cooling hot gases generated during the breaking operations
Data Source
Figure 1~3
Figure 4a~4b
AI summary
A gas exhaust diffuser for a circuit breaker, comprising a first casing (10) extending longitudinally along a principal axis (40) with an open end (11) to allow gas to enter and a closed end (12), and a second casing (20) coaxial to the first casing (10), extending along the principal axis, with at least one outlet (21) to allow gas to escape, the closed end (12) of the first casing (10) being arranged in the second casing (20) and the first casing (10) having at least two radial openings (13) near its closed end to provide a fluid communication between the first and second casing, wherein a plurality of incurved elements (30) are positioned radially in the second casing at the at least one radial opening (13) to create a rotation of an entering exhaust flow in a plan perpendicular to the principal axis, thereby generating a substantially helicoidally-shaped exhaust flow path in the second casing.