Ship Tank Support Structure for Thermal Contraction and Load Dispersion
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Solution Overview
Problem
Existing support structures for liquefied gas tanks in ships face challenges in reducing heat transfer and accommodating thermal contraction while maintaining load-bearing capacity during ship oscillations.
Innovation Solution
A support structure featuring hollow units with cylindrical elements and sliding outer members, where one support unit is fixed and the other is slidable, with a lubricating liner to reduce friction, allowing for axial displacement and accommodating tank length reduction due to thermal contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If block-shaped thermal-insulating liners are used in support units, then the tank can accommodate thermal contraction, but a large amount of heat enters the tank from the outside via the thermal-insulating liners
Solution Approach 1:
The support unit is divided into multiple cylindrical elements arranged in the circumferential direction of the tank. Each cylindrical element is a hollow structure with small cross-sectional area, creating multiple segmented heat barrier paths instead of a single large thermal bridge. This segmentation reduces overall heat transfer while maintaining the ability to accommodate thermal contraction through axial displacement of the support units.
2Object-affected harmful factors
If a hollow support unit with small cross-sectional area is used to reduce heat transfer area, then heat transfer is reduced, but it is difficult to bear the load of the tank when the ship oscillates and difficult to displace in the axial direction
Solution Approach 1:
The support unit transitions from a solid block structure to a hollow cylindrical structure with walls extending in the axial direction. This dimensional change allows the support unit to achieve high strength-to-weight ratio and load-bearing capacity through the cylindrical geometry and wall thickness, while the hollow interior minimizes heat transfer area. The cylindrical elements can effectively bear ship oscillation loads while maintaining low thermal conductivity.
3Adaptability or versatility
If the outer members of the second support unit are made slidable on the curved surface, then the tank can accommodate reduction in length due to thermal contraction, but friction and shear forces increase
Solution Approach 1:
A lubricating liner is introduced as an intermediary layer between the curved surface and the outer members of the second support unit. This lubricating liner reduces friction and shear forces during the sliding motion that accommodates thermal contraction. The lubricating liner enables smooth relative movement between the support unit and tank, reducing harmful frictional forces while maintaining the adaptability to accommodate axial displacement from thermal contraction.
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 solution effectively disperses ship oscillation loads and accommodates thermal contraction, reducing heat transfer and preventing excessive shear forces, thus maintaining tank stability and efficiency in storing low-temperature gases.
Implementation Method 1
a lubricating liner being sandwiched between the curved surface and the outer members of the second support unit
Implementation Method 2
it is desirable that heat transfer by the support unit be reduced... hollow support unit with a small cross-sectional area in order to reduce a heat transfer area
Implementation Method 3
when a reduction in the length of the tank (i.e., deformation of the tank in its axial direction) occurs due to thermal contraction
Data Source
Figure 1
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AI summary
A support structure of a ship tank includes: a curved surface facing an outer peripheral surface of a horizontal type cylindrical tank (2); and a pair of support units (4A, 4B) supporting the tank 2 on the curved surface. Each of the support units includes: a plurality of cylindrical elements (5) arranged in a circumferential direction of the tank (2) such that an axial direction of each of the cylindrical elements (5) coincides with a radial direction of the tank (2); a plurality of inner members each holding an end portion of a corresponding one of the cylindrical elements (5) at the tank (2) side; and a plurality of outer members each holding an end portion of a corresponding one of the cylindrical elements (5) at an opposite side to the tank (2). The inner members are fixed to the tank (2). The outer members of one of the support units (4A) are configured such that displacement of the outer members in an axial direction of the tank (2) relative to the curved surface is restricted. The outer members of the other one of the support units (4B) are configured to be slidable on the curved surface in the axial direction of the tank (2).