Double-Shelled Tank Dome Alignment During Thermal Contraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In double-shell tanks used for transporting and storing liquefied gases, thermal contraction of the inner shell leads to excessive load on pipes penetrating the inner and outer shell domes, due to misalignment caused by differential thermal expansion, which can result in pipe failure and inefficiency.
Innovation Solution
A horizontal type cylindrical double-shell tank design incorporating a deformable member within the outer shell dome, a first restricting mechanism to manage axial movement, and a second restricting mechanism to control radial movement, allowing the inner shell dome to contract while maintaining alignment and reducing load on pipes, with tubular members made of low thermal conductivity materials like GFRP to minimize heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the inner shell is fixed at a position away from the inner shell dome, then the structural stability is improved, but the relative positional relationship between the inner shell dome and outer shell dome changes greatly due to thermal contraction, causing excessive load on pipes
Solution Approach 1:
The patent applies the dynamics principle by making the outer shell dome movable rather than fixed, allowing it to move in the axial direction to follow the inner shell dome's thermal contraction. This dynamic adjustment prevents excessive load on pipes while maintaining structural stability, directly resolving the technical contradiction between stability and pipe load.
2Loss of energy
If the inner shell dome is entirely covered by a vacuum space, then thermal insulation is improved, but the inner shell dome cannot accommodate its thermal contraction, leading to misalignment with the outer shell dome
Solution Approach 1:
The outer shell dome is designed to move dynamically in the axial direction to accommodate the inner shell dome's thermal contraction while maintaining the vacuum space for thermal insulation. This resolves the contradiction by allowing shape adjustment without compromising insulation.
Solution Approach 2:
The outer shell dome is divided into a fixed part and a movable part by a deformable member. The movable part can move axially to follow the inner shell dome's contraction, while the fixed part maintains the vacuum space structure. This segmentation allows simultaneous achievement of thermal insulation and positional accommodation.
3Strength
If rigid supporting members are used to support the inner shell dome, then structural strength is improved, but shear stress is exerted on the supporting members during thermal contraction
Solution Approach 1:
The patent replaces rigid supporting members with flexible bellows pipes that can expand and contract axially. These flexible members provide structural support while accommodating thermal contraction through their deformability, eliminating shear stress. This directly applies the flexible shells principle to resolve the contradiction between strength and stress.
4Ease of manufacture
If straight pipes are used to penetrate the inner and outer shell domes, then ease of manufacture is improved, but excessive load during thermal contraction causes pipe failure
Solution Approach 1:
The patent replaces straight rigid pipes with flexible bellows pipes that can bend and deform axially. These flexible pipes maintain ease of manufacture through standardized components while providing the reliability needed to accommodate thermal contraction without failure, directly resolving the contradiction between manufacturability and reliability.
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 suppresses the load on pipes by allowing the outer shell dome to move with the inner shell dome during contraction, reducing shear stress and heat transfer, thereby preventing pipe failure and enhancing thermal insulation.
Implementation Method 1
when the liquefied gas is fed into the inner shell, thermal contraction of the inner shell occurs
Implementation Method 2
The outer shell forms a vacuum space as a thermal insulating layer between the inner shell and the outer shell
Implementation Method 3
tubular members made of low thermal conductivity materials like GFRP to minimize heat transfer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A horizontal type cylindrical double-shell tank (2A) includes: an inner shell (3) including an inner shell main part (31) and an inner shell dome (32); and an outer shell (4) including an outer shell main part (41) and an outer shell dome (42). The outer shell dome (42) incorporates therein a deformable member (5). A first restricting mechanism (6) is disposed between a movable part (42A) of the outer shell dome (42) and the inner shell dome (32). A second restricting mechanism (7) is disposed between a fixed part (42B) of the outer shell dome (42) and the inner shell dome (32). The first restricting mechanism (6) restricts movement of the movable part (42A) of the outer shell dome (42) and movement of the inner shell dome (32) relative to each other in a particular direction while allowing the inner shell dome (32) to contract. The second restricting mechanism (7) restricts movement of the inner shell dome (32) in a radial direction while allowing the inner shell dome (32) to contract and allowing the inner shell dome (32) to move in the particular direction relative to the fixed part (42B) of the outer shell dome (42).