Ellipsoidal Membrane Rupture Control in Epoxy Insulated Tanks
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Solution Overview
Problem
Existing pressure limiting membranes in insulating casings of electrical protection devices face challenges in controlling crack propagation and maintaining vessel integrity during internal arcs, with high dispersion in rupture pressures and sensitivity to manufacturing defects, especially on Epoxy tanks.
Innovation Solution
An ellipsoidal membrane with a curvature ratio between 1.2 and 1.8 and a collar thickness ratio between 3 and 6, ensuring controlled stress distribution and low rupture pressure, along with a connection line radius of curvature greater than or equal to 1 mm to minimize stress concentration and manufacturing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a small radius of curvature (0-1 mm) is used at the junction between membrane and wall to create stress concentration, then rupture pressure can be controlled, but manufacturing precision requirements increase exponentially and mold wear effects are amplified
Solution Approach 1:
The patent changes the geometric parameters of the membrane, specifically using an ellipsoidal shape with controlled radius ratios (1.2-1.8) and optimized connection line radius (≥1 mm). This parameter optimization maintains stress concentration for rupture control while reducing sensitivity to manufacturing variations and mold wear, thereby resolving the contradiction between rupture pressure control and manufacturing precision requirements
Solution Approach 2:
The patent applies an ellipsoidal curvature to the membrane instead of a simple spherical or flat shape. The specific radius ratio between the major and minor axes (1.2-1.8) creates optimal stress distribution that ensures controlled rupture while being less sensitive to manufacturing tolerances, thus resolving the contradiction between stress concentration and manufacturing precision
2Stress or pressure
If metal membranes are attached to metal tanks, then good rupture control is achieved, but implementation on Epoxy tanks becomes very difficult
Solution Approach 1:
The patent uses an integral Epoxy membrane structure that is monolithic with the Epoxy tank, eliminating the need for separate metal membranes and complex attachment processes. The ellipsoidal geometry with optimized thickness ratios creates the necessary stress concentration and rupture control entirely within the Epoxy material itself, resolving the contradiction between rupture control and ease of manufacture on Epoxy tanks
Solution Approach 2:
The patent merges the membrane and tank into a single integral structure, where the membrane is formed as an inherent part of the tank wall with optimized thickness variation. This integration eliminates manufacturing complexity associated with separate components and attachment processes, while maintaining rupture control through the ellipsoidal geometry, thus resolving the contradiction between rupture control and ease of manufacture
3Ease of manufacture
If Epoxy membranes are integrated on Epoxy tanks, then manufacturing is simplified, but crack propagation is uncontrolled and rupture pressure shows high dispersion
Solution Approach 1:
The patent applies an ellipsoidal curvature to the integrated membrane with specific radius ratios (1.2-1.8) that create controlled stress concentration patterns. This geometric optimization ensures that cracks propagate in a predictable manner from the connection line, reducing dispersion in rupture pressure while maintaining the manufacturing simplicity of integrated Epoxy construction, thus resolving the contradiction between ease of manufacture and reliability
4Stress or pressure
If membrane thickness is reduced to lower rupture pressure, then pressure limiting capability is improved, but structural integrity and crack control become more difficult
Solution Approach 1:
The patent segments the membrane thickness strategically, with the connection line area having greater thickness (≥1 mm) to maintain structural integrity and control crack initiation, while other areas can be thinner to achieve lower rupture pressure. The ellipsoidal geometry with optimized thickness ratios (membrane to collar between 3 and 6) creates this beneficial segmentation, resolving the contradiction between rupture pressure level and structural integrity
Solution Approach 2:
The patent applies different thickness qualities to different locations of the membrane structure. The connection line region has increased thickness and optimized radius of curvature to provide strength and control crack propagation, while the main membrane body can be thinner for pressure limiting. This local differentiation of structural quality resolves the contradiction between overall structural integrity and localized rupture pressure control
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 configuration reduces the parameters influencing rupture pressure, ensures controlled crack propagation, and provides a sufficient evacuation section for plasma gases, minimizing the risk of tank degradation and maintaining operational phases with reduced costs and weight.
Implementation Method 1
the ratio between the largest radius and the smallest radius of curvature, this making it possible to obtain two points of rupture of the membrane corresponding to two points of concentration of maximum stresses
Implementation Method 2
in the presence of a fault in internal arc inside said casing resulting in a sudden rise in pressure above a certain value inside said casing, is capable of creating, under the effect of this increase in pressure, a passage through the wall of the casing, this passage allowing a directed release of the plasma generated during the internal defect
Data Source
Figure 1~2
Figure 3
AI summary
The device has a membrane (4) creating a passage through a wall of an envelope of a tank, made of metal or epoxy, under the effects of increase in pressure. The membrane is formed in ellipsoidal shape, where the membrane presents a ratio between large bending radius (R1) and small bending radius (R2) of the membrane in the range of 1.2 and 1.8, for obtaining two break points (A, B) corresponding to two maximum constraint points of the membrane and for obtaining gradual decreasing distribution of constraints along the ellipsoidal shape of the membrane.