Double-Shell Ship Tank Dome Support Mechanism
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Solution Overview
Problem
In double-shell ship tanks, the relative position between the inner and outer shells is not effectively restricted, leading to stress on penetrating pipes due to inertial forces and thermal contraction of the inner shell, which can cause displacement and compromise the integrity of the tank during ship movements and temperature changes.
Innovation Solution
The implementation of at least three support mechanisms around the inner shell dome, comprising a first support member, a second support member, and an insulating member that can slide parallel to the reference plane, allowing for thermal contraction while maintaining the dome-to-dome relative position, with the insulating member made of glass fiber reinforced plastic to minimize heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid support structures are used to restrict dome-to-dome relative position, then the relative position is effectively controlled, but thermal contraction of the inner shell dome is restricted causing stress and potential damage
Solution Approach 1:
The support mechanism changes the physical state of the insulating member from fixed to movable, allowing it to slide along the first supporting surface. This parameter change enables the support to accommodate thermal contraction while maintaining position control
Solution Approach 2:
The support mechanism transitions from a static rigid connection to a dynamic sliding connection. The insulating member can move dynamically in response to thermal contraction, preventing stress accumulation while maintaining structural stability
2Strength
If no support mechanism is used to allow thermal contraction, then the inner shell dome can contract freely, but the dome-to-dome relative position is not restricted causing stress on penetrating pipes during ship movement
Solution Approach 1:
The insulating member acts as an intermediary element between the first and second support members. It mediates between the need for position control and thermal contraction, providing a sliding connection that satisfies both requirements
Solution Approach 2:
The sliding function is extracted as a separate capability of the insulating member, allowing it to independently handle thermal contraction while the support members maintain position control
3Device complexity
If support members are directly connected without insulating members, then the structure is simpler, but heat transfer from outer shell to inner shell occurs compromising liquefied gas storage
Solution Approach 1:
The insulating member serves as a thermal intermediary, blocking heat transfer between the outer and inner shells while maintaining the mechanical support function. This intermediary layer prevents thermal conduction without adding significant structural complexity
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
This configuration effectively restricts the dome-to-dome relative position, allowing for thermal contraction of the inner shell while preventing stress on pipes and maintaining the structural integrity of the tank, ensuring the liquefied gas is kept at low temperatures for extended periods.
Implementation Method 1
when a liquefied gas is fed into the inner shell, the temperature of the entire inner shell is lowered. As a result, thermal contraction of the inner shell dome occurs in the axial direction and the radial direction
Implementation Method 2
an insulating member interposed between the first supporting surface and the second supporting surface, the insulating member being fixed to the second supporting surface and configured to slide along the first supporting surface
Data Source
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AI summary
A double-shell ship tank includes: an inner shell including an inner shell main part storing a liquefied gas and an inner shell dome protruding upward from the inner shell main part; an outer shell including an outer shell main part surrounding the inner shell main part and an outer shell dome surrounding the inner shell dome; and at least three support mechanisms disposed around the inner shell dome between the inner shell and the outer shell. Each of the support mechanisms includes: a first support member fixed to one of the inner shell and the outer shell, the first support member including a first supporting surface parallel to a reference plane that includes a central axis of the inner shell dome; a second support member fixed to the other one of the inner shell and the outer shell, the second support member including a second supporting surface facing the first supporting surface; and an insulating member interposed between the first supporting surface and the second supporting surface, the insulating member being fixed to the second supporting surface and sliding along the first supporting surface. One of the first support member and the second support member, the one support member being fixed to the inner shell, is positioned on the reference plane.