Cellular Rubber Self-Sealing with Capillary Interlayer
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Solution Overview
Problem
Existing multilayer self-sealing devices for containers, such as gasoline tanks, are ineffective in rapidly sealing perforations caused by bullet impacts when the container contains heavier fuels like diesel, due to slower diffusion rates of diesel in cellular rubber, leading to unsatisfactory leak minimization.
Innovation Solution
A multilayer device with internal and external rubber layers, where at least one external layer is made of cellular rubber, connected by an interlayer fibrous structure based on non-woven fibers that accelerates liquid diffusion and swelling for rapid self-sealing, utilizing a non-woven sheet capable of absorbing and distributing the liquid across the rubber layers for swift swelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cellular rubber layers are used for self-sealing in containers with heavier fuels like diesel, then the device can provide self-sealing functionality, but the swelling rate is too slow (100-200%) to effectively minimize leaks
Solution Approach 1:
An interlayer made of hydrophilic porous material (cellulose acetate or starch-based) is introduced between the cellular rubber layers and the diesel fuel. This intermediary layer absorbs the diesel fuel rapidly through capillary action and transfers it to the rubber layers, accelerating the swelling process from 100-200% to over 300% swelling rate, achieving effective self-sealing for diesel fuel containers
Solution Approach 2:
The interlayer utilizes porous material with high capillary action (cellulose acetate or starch-based porous structure) to rapidly absorb and transport diesel fuel to the rubber layers. The porous structure enables fast fuel uptake and distribution, transforming the slow diffusion process into rapid capillary-driven transport for immediate rubber swelling
2Reliability
If multiple rubber layers are used to improve self-sealing, then the sealing capability is enhanced, but the device complexity increases
Solution Approach 1:
Multiple rubber layers are merged with an interlayer of hydrophilic porous material to create a composite multilayer structure. This combination integrates the swelling capability of rubber with the rapid absorption capability of porous material, achieving enhanced self-sealing performance while maintaining manageable structural complexity through functional integration
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 interlayer structure significantly enhances the swelling kinetics of cellular rubber, allowing for rapid self-sealing of perforations in containers holding diesel, kerosene, and other fuels, improving the sealing time from minutes to instantaneous, effectively minimizing leaks.
Implementation Method 1
the or each interlayer structure comprises at least one sheet based on non-woven fibers which is absorbent with respect to said liquid and capable of accelerating the diffusion of the absorbed liquid over the entire surface of the or each layer of cellular rubber
Implementation Method 2
accelerating the diffusion of the absorbed liquid over the entire surface of the or each layer of cellular rubber
Implementation Method 3
self-sealing being generally obtained by the inflation of one or more layers of cellular rubber that the device contains in contact with the gasoline that has leaked through the perforation. Indeed, this swelling, through the significant and rapid increase in volume due to the diffusion of the gasoline in the rubber
Data Source
Figure 1~3
Figure 4
AI summary
The multilayered device (201) comprises internal rubber layers (202) and external rubber layers (203a, 203b) for a wall (6), and an intermediate fibrous structure for connecting two of the adjacent layers. The external layer is made of foam rubber for self-sealing a wall perforation by inflation and by contacting with the liquid. Each intermediate structure comprises a sheet made of non-woven fibers, which are absorbs the liquid by capillarity and dipping in the liquid for accelerating diffusion of the liquid absorbed on the surface of each foam rubber layer contacting with the sheet. The multilayered device (201) comprises internal rubber layers (202) and external rubber layers (203a, 203b) for a wall (6), and an intermediate fibrous structure for connecting two of the adjacent layers. The external layer is made of foam rubber for self-sealing a wall perforation by inflation and by contacting with the liquid. Each intermediate structure comprises a sheet made of non-woven fibers, which are absorbs the liquid by capillarity and dipping in the liquid for accelerating diffusion of the liquid absorbed on the surface of each foam rubber layer contacting with the sheet and for accelerating and increasing its swelling to obtain the self-sealing in short time. The liquid is greater than 200% of the mass of the structure before dipping. The intermediate structure has a weight of 50-200 g/m 2> and a thickness of 0.5-5 mm, and is constituted of single sheet formed by a non-woven of surface density of 150-200 g/m 2>. Each sheet is formed by a non-woven or a paper absorbent e.g. blotter. The non-woven is made of polypropylene according to the name OIL PAD 200 for absorbing by capillarity of a diesel fuel of mass greater than 1000% of the non-woven before it is dipped in the fuel. Each of the foam rubber layers is constituted by a crosslinked and expanded rubber composition having open cells and a density of 0.2-0.4. The rubber layers are fixed together by a mechanical unit between the points such as staples, rivets or stitches that are spaced at right of the layers to enhance their swelling in case of perforation. The outermost rubber layer is surrounded, by pasting, of external coatings for increasing the mechanical strength, rigidity and/or fireproofing of the container.