Membrane Tank Insulation Panel Slit Design for Stress Reduction

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Solution Overview

Problem

Panel type membrane storage tanks experience significant contraction-induced displacement and hull motion-induced stress at cryogenic temperatures, leading to potential cracking of secondary sealing walls due to the high thermal expansion of foam insulators and direct attachment to the hull.

Innovation Solution

The insulation structure features secondary and primary insulation panels with strategically placed slits and securing devices on the secondary insulation panels to prevent transverse and longitudinal displacement, coupled with offset arrangements to maximize support points and reduce relative panel displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If foam insulators with high thermal expansion are used in panel type membrane storage tanks, then insulation performance is improved, but thermal contraction and hull motion cause significant displacement and stress at securing device anchoring points

Engineering Contradiction:

Improveinsulation performanceVSAvoidstructural integrity at anchoring points

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The secondary insulation wall is divided into multiple secondary insulation panels, each with independent slits. This segmentation allows each panel to independently accommodate thermal contraction and hull motion through the slits, preventing stress concentration at the anchoring points of securing devices while maintaining insulation performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Slits are strategically positioned in the secondary insulation panels at specific locations away from the anchoring points of securing devices. This local modification allows the insulation panels to deform locally through the slits during thermal contraction or hull motion, protecting the anchoring points from stress while maintaining the overall insulation structure.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If secondary insulation panels are directly attached to the hull, then installation simplicity is improved, but hull motion is directly transferred to the panels causing stress and potential failure

Engineering Contradiction:

Improveinstallation simplicityVSAvoidhull motion induced stress

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The slits in the secondary insulation panels act as intermediary elements that decouple the direct transmission of hull motion to the insulation panels. When the hull moves, the slits allow the panels to deform and absorb the motion, preventing direct stress transfer to the primary insulation wall and secondary sealing wall while maintaining the simple attached installation structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If securing devices are disposed on secondary insulation panels, then primary insulation wall support is improved, but thermal contraction causes displacement of anchoring points leading to stress concentration

Engineering Contradiction:

Improvesupport structure for primary insulation wallVSAvoidstress concentration in sealing walls

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The slits are pre-positioned in the secondary insulation panels at locations that anticipate and accommodate thermal contraction movements. Before thermal contraction occurs, the slits are already in place to allow panel deformation, preventing displacement of the anchoring points of securing devices and avoiding stress concentration in the secondary sealing wall and primary insulation wall.

Inventive Principle:

Principle #10Preliminary action

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 stabilizes the anchoring points of the securing devices, preventing stress concentration in the primary and secondary insulation walls and enhancing the structural integrity and productivity of the insulation system.

Implementation Method 1

Panel type membrane storage tanks experience significant contraction-induced displacement and hull motion-induced stress at cryogenic temperatures

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

The primary and secondary insulation walls are provided in the form of a sandwich panel fabricated by bonding plywood to an upper surface and/or a lower surface of high-density polyurethane foam (PUF)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS12173851B2Insulation structure of membrane type storage tank

Publication Date: 2024.12.24 HANWHA OCEAN CO LTD (KR)

AI summary

An insulation structure of a membrane type storage tank is disclosed. The membrane type storage tank includes a secondary insulation wall comprising a plurality of secondary insulation panels; a primary insulation wall which comprises a plurality of primary insulation panels, and which is disposed at the upper part of the secondary insulation wall; and a plurality of fixing devices provided at the upper parts of the secondary insulation panels to be coupled with the primary insulation panels, wherein the plurality of fixing devices are arranged on the center line of the secondary insulation panels in a width direction so that the movement of the fixing devices in the width direction is prevented, and the plurality of fixing devices are arranged to be spaced at equal intervals with respect to the longitudinal direction of the secondary insulation panels.