Knobbed Aluminum Foil Lining for Double-Walled Tank Leak Protection
Solution Overview
Problem
Existing leak protection linings with knobbed metal foils face challenges such as reduced compressive strength, tendency to unroll, and high material usage, leading to instability and inefficiency in application and manufacturing of double-walled tanks.
Innovation Solution
A knobbed aluminum foil with regularly arranged nubs, where adjacent nubs are offset and connected via small elevations, providing enhanced compressive strength and stability, combined with a plastic coating and glass fiber reinforcement for improved adhesion and leak detection, allowing for efficient production of double-walled tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional aluminum knob foils are used with manually applied plastic resin, then the coating can be applied, but the compressive strength is reduced and a large amount of coating material is needed
Solution Approach 1:
The foil is divided into strip areas with knobs arranged in offset rows, creating a segmented structure where each knob supports the coating locally. This segmentation allows the coating to be applied more efficiently and reduces the total amount of coating material needed while maintaining compressive strength through the distributed knob structure.
Solution Approach 2:
The knobs are arranged in asymmetric offset rows where adjacent strip areas have knobs positioned at different locations. This asymmetric arrangement creates interlocking patterns that enhance compressive strength and reduce the need for extensive coating material, as the structure itself provides structural integrity.
2Ease of manufacture
If conventional aluminum bubble wraps are used, then the coating can be applied, but the bulges tend to be compressed during processing and the coating is easily detached under bending stress
Solution Approach 1:
The foil structure is segmented into discrete knobs arranged in offset rows, which prevents the compression of bulges during processing. Each knob acts as an independent support element, maintaining its shape and preventing the coating from detaching under bending stress.
Solution Approach 2:
The knobs are pre-formed and positioned in offset rows before coating application. This preliminary arrangement ensures that the structure is already optimized for both processing stability and coating adhesion, preventing compression issues and detachment problems that occur with conventional bubble wraps.
3Ease of manufacture
If conventional knobbed foils are used, then the coating can be applied, but a relatively large amount of coating material is needed and the coating is easily detached
Solution Approach 1:
The foil is segmented into strip areas with knobs in offset rows, creating a pattern that reduces the total surface area requiring coating. The knobs are positioned to provide structural support at critical points, allowing less coating material to be used while maintaining manufacturing ease and coating stability.
Solution Approach 2:
The asymmetric offset arrangement of knobs creates a pattern that optimizes both coating application and material usage. The irregular positioning of knobs in adjacent strip areas ensures efficient coating distribution and reduces the quantity of coating material needed compared to conventional symmetric patterns.
Data Source
Figure 1~2
Figure 3~4
AI summary
Lining made from an aluminum foil (11) comprises nubs (13) having a rectangular cross-sectional surface (14) and surface regions (31) with shorter extension than the nubs. Neighboring nubs are displaced in neighboring strip regions and one nub of the strip region lies on nubs of a neighboring strip region. An independent claim is also included for a double-walled tank or container for liquids with the above lining. Preferred Features: The surface regions of the nub foil is planar. The nubs are 0.8-1.2 mm high.