Linerless Composite Storage Tank Permeation Barrier

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Solution Overview

Problem

Conventional composite storage tanks used in aerospace and other applications face issues with weight addition due to metal liners, susceptibility to leakage from coefficient of thermal expansion mismatches, and difficulty in integrating internal structures, which compromises the containment of small molecule gases like hydrogen and oxygen.

Innovation Solution

A linerless composite storage tank design featuring multiple layers with an inner composite region, a permeation barrier strategically positioned between the inner and outer composite regions, and a venting layer to manage any leakage, reducing weight and enhancing structural integrity while preventing gas permeation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal liner is used to prevent gas permeation, then the containment reliability is improved, but the weight of the tank increases

Engineering Contradiction:

Improvecontainment reliabilityVSAvoidtank weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent uses a composite material structure consisting of an inner composite region, a permeation barrier layer, and an outer composite region. This composite structure provides both the permeation prevention capability of a liner and the lightweight benefits of composite materials, resolving the contradiction between containment reliability and weight.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The permeation barrier is strategically positioned between the inner and outer composite regions where it is most needed for gas containment. This localized approach provides effective permeation prevention only in the critical area while minimizing overall weight compared to a full metal liner.

Inventive Principle:

Principle #3Local quality

2Weight of moving object

If a thin liner is used to reduce weight, then the tank weight decreases, but the liner becomes susceptible to disbond and damage

Engineering Contradiction:

Improvetank weightVSAvoidliner integrity

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The patent replaces the thin metal liner with a composite structure that includes a permeation barrier layer sandwiched between inner and outer composite regions. This composite construction provides both weight reduction and enhanced mechanical integrity, preventing disbond and damage issues associated with thin metal liners.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges the structural support function and the permeation barrier function into a single integrated composite structure. The inner composite region provides structural support while the permeation barrier provides gas containment, eliminating the need for a separate thin liner that would be susceptible to damage.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If a metal liner is used to contain gases, then the gas containment is improved, but the complexity of supporting internal structures increases

Engineering Contradiction:

Improvegas containmentVSAvoidstructural integration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the gas containment function and the structural support function for internal components into a single integrated composite structure. The inner composite region and permeation barrier are formed as one unit, allowing internal structures like baffles and port hardware to be supported directly by the composite material without compromising gas containment or adding additional complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 reduces the weight of composite tanks, enhances their structural integrity, and prevents gas leakage, enabling safer and more reliable storage of volatile fluids over extended periods, suitable for long-duration space missions.

Implementation Method 1

The at least one permeation barrier may be formulated and configured to substantially inhibit permeation of a fluid contained in the composite storage tank

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

Fiber-reinforced composite materials provide relatively lightweight and high strength structures

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Data Source

PatentUS11559964B2Composite structures, composite storage tanks, vehicles including such composite storage tanks, and related systems and methods

Publication Date: 2023.01.24 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A composite storage tank may include a wall structure including at least three regions including an inner region, an outer region, and at least one permeation barrier. Another region may be optionally incorporated for venting potential permeation of fluids. The at least one permeation barrier and/or the venting layer may be strategically positioned between the inner region and the outer region to reduce or at least partially prevent fluid permeation of the inner region or the outer region. A vehicle may include such a composite storage tank. Methods of forming a composite fluid storage tank may include forming an inner composite region, applying a permeation barrier to an outer surface of the inner composite region, forming an outer composite region, and curing the inner composite region and the outer composite region with the permeation barrier to form the composite fluid storage tank.