Insulating Block Stiffener Layout for Cryogenic Tank Wall Flexing
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Solution Overview
Problem
Existing insulating blocks for low-temperature liquefied gas tanks experience flexing due to thermal gradients and structural deformations, leading to stress concentrations and potential failure of the waterproofing membrane.
Innovation Solution
The insulating block design includes stiffeners attached to the base plate, extending along the sides of the block, with free-contact surfaces to limit deflection and prevent stress concentration, and recesses for retaining devices to secure the blocks in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the insulating foam block is bonded to the base plate and cover plate, then the insulating block maintains structural integrity, but the foam block experiences flexing due to thermal gradients and structural deformations
Solution Approach 1:
The foam block is segmented into multiple sections by introducing foam partition walls that extend from the base plate to the cover plate. This segmentation divides the large foam block into smaller independent sections, allowing each section to flex independently and reducing overall flexing stress on the bonded structure.
Solution Approach 2:
Foam partition walls are strategically positioned at specific locations within the foam block based on thermal gradient analysis and structural deformation patterns. These partitions are placed where flexing stress is most critical, providing localized reinforcement without adding unnecessary complexity throughout the entire structure.
2Ease of manufacture
If the insulating block is made as a single integrated unit, then manufacturing is simplified, but stress concentrations develop during operation due to thermal and structural variations
Solution Approach 1:
The foam block is divided into multiple sections using foam partition walls, creating a segmented structure that reduces stress concentration. Each segment can deform independently in response to thermal and structural variations, preventing stress buildup at single points while maintaining overall structural integrity.
Solution Approach 2:
The insulating block combines different materials with complementary properties: foam material for thermal insulation, plywood or composite plates for structural strength, and metal stiffeners for additional rigidity. This composite construction allows each material to perform its optimal function while working together to reduce stress concentrations.
3Strength
If stiffeners are added to reduce flexing of the foam block, then structural rigidity is improved, but the complexity of the insulating block increases
Solution Approach 1:
Stiffeners are placed only at critical locations where flexing stress is most severe, such as at the corners and along the edges of the foam block, rather than uniformly across the entire structure. This localized approach provides maximum rigidity enhancement with minimum added complexity.
Solution Approach 2:
The stiffeners are integrated with the existing composite structure of the insulating block, combining wood, foam, and metal elements. The stiffeners work synergistically with the foam partition walls and plate structures already present in the design, creating a unified rigid framework without requiring entirely new structural systems.
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 design effectively reduces flexing and stress on the insulating foam, maintaining the integrity of the waterproofing membrane and preventing stress concentrations, thereby enhancing the durability and reliability of the tank's thermal insulation.
Implementation Method 1
each stiffener projecting from the base plate in the thickness direction of the insulating block and having a surface in free contact with said lateral surface of the foam block
Implementation Method 2
the temperature difference between the outside and inside of the tank generates a thermal gradient within the insulating blocks
Implementation Method 3
This thermal gradient causes differential contraction within the insulating block, due to the difference in the coefficients of thermal expansion between the plywood and the polyurethane foam
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to an insulating block (6; 106; 206; 306) suitable for making a wall of a sealed and thermally insulating tank. The insulating block comprises a base plate (12; 112; 212; 312), a cover plate (11; 111; 211; 311) and a foam block (13; 113; 213; 313). The insulating block further comprises a pair of stiffeners (20, 21; 120; 250, 251; 380) secured to the base plate and extending along a pair of sides of the base plate, each stiffener protruding from the base plate in the thickness direction of the insulating block and having a surface in free contact with a lateral surface of the foam block. The foam block has a plurality of recesses (15; 115; 215; 315), each recess extending between two adjacent lateral surfaces of the foam block and being intended to receive a retaining member (30), and the insulating block having a bearing surface (16; 116; 216; 316) for the retaining member in the recess.