Insulation Liquid Expansion Assembly With Flexible Gas Bag
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Solution Overview
Problem
The existing insulation liquid expansion assemblies in high voltage devices, which use flexible diaphragms or rubber bags, are complex to design and maintain, prone to damage, and require special monitoring, leading to limited availability and frequent on-site repairs due to their location above the insulation liquid tank.
Innovation Solution
A hermetically sealed expandable interior space is created by a flexible gas bag outside the expansion vessel, connected via a compensation pipe, allowing expansion to occur outside the vessel, with the space filled with a suitable gas to prevent moisture contamination and using pressure means to maintain overpressure, eliminating the need for a diaphragm or rubber bag inside the expansion vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible diaphragm or rubber bag is used to seal the insulation liquid surface in the expansion vessel, then moisture contamination is prevented, but device complexity increases and reliability decreases
Solution Approach 1:
The sealing function is extracted from the expansion vessel interior and relocated to a separate flexible container positioned in the expansion vessel. The flexible container acts as a movable seal that prevents moisture ingress while allowing thermal expansion, thereby reducing the complexity of the expansion vessel structure itself and improving reliability by isolating the critical sealing function to a replaceable component.
Solution Approach 2:
The flexible container is nested within the expansion vessel, creating a hierarchical structure where the flexible container serves as an inner sealing element. This nesting allows the expansion vessel to maintain a simple robust structure while the flexible container provides the necessary sealing function, resolving the contradiction between structural simplicity and sealing effectiveness.
2Ease of repair
If a flexible diaphragm or rubber bag is used in the expansion vessel, then sealing is achieved, but ease of repair deteriorates due to limited access and wearout
Solution Approach 1:
The flexible container is designed as a consumable component with a limited service life that can be easily replaced when worn. This disposable approach eliminates the need for complex repairs, as the entire flexible container can be quickly swapped out rather than attempting to repair the diaphragm or bag. The simple replacement process dramatically improves ease of repair while the component is designed to last sufficiently long under normal operating conditions.
Solution Approach 2:
The sealing function is segmented into a separate flexible container that can be independently replaced. This segmentation isolates the wear-prone sealing component from the permanent expansion vessel structure, allowing the flexible container to be replaced without affecting other components. The modular design enables straightforward maintenance procedures.
3Ease of operation
If the expansion vessel is positioned above the insulation liquid tank, then thermal expansion is accommodated, but ease of operation deteriorates due to limited access for monitoring and repair
Solution Approach 1:
The flexible container is designed to expand and contract vertically in response to thermal expansion, utilizing the vertical dimension within the expansion vessel. This vertical expansion movement allows the system to accommodate temperature changes while keeping the expansion vessel in a fixed position that provides good access for monitoring and maintenance. The flexible container's ability to change volume in the vertical direction decouples the thermal management function from the positioning constraints.
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 solution simplifies the design and maintenance of high voltage devices by preventing moisture contamination and reducing the risk of damage, allowing for flexible placement of the gas bag and ensuring continuous operation with reduced need for on-site repairs, while maintaining the insulation liquid's thermal expansion capabilities.
Implementation Method 1
Due to a thermal expansion of the insulation liquid during operation typically an expansion vessel is foreseen above the vessel
Implementation Method 2
pressure means for applying a pressure force on the interior of the otherwise hermetically sealed compensation pipe
Data Source
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AI summary
The invention is related to an insulation liquid expansion assembly for an insulation liquid tank (12, 52) for a high voltage coil (14), comprising an expansion vessel (22, 58, 74) with an inlet (22) and an outlet (24) opening, wherein the inlet opening (22) is foreseen to be fluidic connected with the insulation liquid tank (12, 52). A compensation pipe (26) is foreseen which is fluidic connected at its first end with the outlet opening (24) of the expansion vessel (22, 58, 74). A flexible gas bag (32, 62, 78) is fluidic connected to the compensation pipe (26) so that a gas can flow from the compensation pipe (26) into the gas bag (32, 62, 78) and backwards. Pressure means for applying a pressure force on the interior of the otherwise hermetically sealed compensation pipe (26).