Sealed Insulating Tank Bottom Wall Sump Structure
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Solution Overview
Problem
Existing membrane tank designs for storing and transporting liquefied gases, such as LNG, face challenges in optimizing cargo volume and unloading efficiency due to the need to maintain a certain liquid height to prevent pump degradation, which is costly and difficult to construct with conventional sump structures.
Innovation Solution
A leaktight and insulating tank design with a sump structure integrated into the bottom wall, featuring a rigid container that interrupts the primary waterproof membrane and includes a support foot and connecting plates for secure sealing, allowing for a larger capacity and easier manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sump structure is used in the bottom wall of a membrane tank, then the pump suction member can be accommodated, but the construction becomes complex and manufacturing becomes difficult due to the need to divert the entire multilayer structure
Solution Approach 1:
The sump structure is segmented into distinct functional components: a rigid container for pump accommodation, a bonding plate for membrane attachment, and a peripheral side wall for structural support. This segmentation allows each component to be manufactured separately and assembled, avoiding the need to divert the entire multilayer structure while maintaining reliability.
Solution Approach 2:
A bonding plate is introduced as an intermediary element between the primary sealed membrane and the rigid container. This bonding plate provides a flat attachment surface for the membrane while allowing the rigid container to extend through the tank bottom wall, simplifying the connection without requiring complex integration of the entire multilayer structure.
2Ease of operation
If a sump structure is constructed to accommodate pump suction, then pump operation is enabled, but the tank's usable cargo volume is reduced due to the space occupied by the sump
Solution Approach 1:
The rigid container of the sump structure extends in the thickness direction of the bottom wall, utilizing the vertical dimension rather than occupying horizontal cargo space. This dimensional approach allows the sump to accommodate the pump suction member while minimizing impact on the tank's usable cargo volume.
3Ease of operation
If the primary sealed membrane is interrupted by a sump structure, then pump access is achieved, but the sealing reliability may be compromised
Solution Approach 1:
The bonding plate serves as an intermediary that maintains the sealed connection between the primary sealed membrane and the tank interior. The membrane is hermetically attached to the bonding plate, which in turn connects to the rigid container, ensuring sealing integrity is maintained even though the membrane is interrupted by the sump structure.
Solution Approach 2:
The sump structure employs a composite arrangement combining the flexible primary sealed membrane with the rigid container and bonding plate. This composite construction allows the membrane to maintain its sealing function while being integrated with the rigid structural elements needed for pump accommodation.
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 enhances cargo volume optimization and unloading efficiency by maintaining the suction member immersion and reducing construction complexities, ensuring reliable operation and efficient liquid handling.
Implementation Method 1
a primary thermal insulation barrier (6) disposed between the primary sealed membrane (7) and the secondary sealed membrane (5)
Implementation Method 2
a secondary thermal insulation barrier (4) disposed between the secondary sealed membrane (5) and the internal wall of the double hull
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An internal bottom wall (3) of the double hull bears a well structure comprising a rigid container (11) that is arranged through the thickness of the bottom wall of the tank and is intended to accommodate a suction member (1) of a pump. The rigid container comprises a bottom wall (13) situated further towards the outside than the secondary sealed membrane (5) of the bottom wall of the tank. The well structure comprises a primary connecting plate (14) surrounding the container, the primary connecting plate having a connecting surface extending parallel to the primary sealed membrane of the bottom wall of the tank, the primary sealed membrane (7) of the bottom wall of the tank being attached to the connecting surface in a sealed manner all around the well structure.