CFRP Tank Connection System with Reinforcing Ring

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Solution Overview

Problem

Existing CFRP pressure tanks for fire extinguishing systems face challenges with high-pressure connections, particularly at the lateral surface, which compromises statics and leads to leakage issues under pressure peaks, and existing solutions do not provide adequate sealing or support for such configurations.

Innovation Solution

A connection system featuring a reinforcing ring with a flat upper side, tapered edge, and circumferential seals, which is arranged in an indentation around the opening to distribute pressure evenly and prevent leaks, allowing for a shell-side opening while maintaining structural integrity under high pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a connection is made on the lateral surface of the CFRP pressure tank, then the tank can be used for fire extinguishing systems requiring side connections, but the structural integrity is compromised and leakage occurs under pressure peaks

Engineering Contradiction:
Improveconnection configurationVSAvoidsealing performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The connection system is divided into separate functional components: a closure element for sealing the opening, a reinforcing ring for structural support, and seals for preventing leakage. This segmentation allows each component to be optimized for its specific function while working together to resolve the contradiction between adaptability and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The closure element and reinforcing ring are pre-assembled as an integrated unit before being installed in the lateral opening. This preliminary assembly ensures proper positioning and sealing configuration, preventing leakage issues that would occur with post-installation adjustments under pressure peaks.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If a connection opening is created in the CFRP shell, then side connections are enabled, but the fiber winding is interrupted and structural strength is reduced

Engineering Contradiction:
Improveconnection accessibilityVSAvoidstructural integrity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The reinforcing ring provides localized structural reinforcement around the connection opening, compensating for the interrupted fiber winding in that specific area. This allows the rest of the tank to maintain its optimized fiber winding pattern while the opening area receives additional strength where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The connection system uses a composite structure combining the CFRP tank material with a reinforcing ring made of suitable material that integrates with the CFRP. This composite approach maintains the high strength-to-weight ratio while enabling the connection opening.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the tank operates under constant high pressure, then fire extinguishing readiness is maintained, but pressure peaks during propellant injection cause leakage at side connections

Engineering Contradiction:
Improveoperational readinessVSAvoidpressure-induced leakage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing system is designed with pre-compression seals that are already under compression before pressure peaks occur. This beforehand cushioning ensures that when pressure peaks occur during propellant injection, the seals maintain contact and prevent leakage without requiring additional protective measures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The closure element acts as an intermediary between the internal tank pressure and the external connection, distributing the pressure loads evenly around the opening. This mediator function prevents concentration of stress at any single point, eliminating leakage paths during pressure peaks.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 ensures complete sealing and effective pressure distribution, enhancing the structural integrity and safety of the CFRP pressure tank, enabling its use under high pressures without compromising statics or increasing material fatigue.

Implementation Method 1

the CFRP winding can be applied in a single plane and can be effectively supported in the area of the opening by the reinforcing ring

Methodology Applied
Scientific EffectPressure distribution: Pascal's Law

Implementation Method 2

circumferential seals which are arranged on the reinforcing ring, so that the opening is sealed both between the liner and the reinforcing ring and between the reinforcing ring and the closure means

Methodology Applied
Scientific EffectContact sealing: Friction

Data Source

PatentEP4053445B1Connection system for cfk pressurised tank, cfk pressurised tank and manufacturing method
Publication Date: 2024.10.09 KRAUSE MAIK
  • EP4053445B1 patent drawingFigure 1
  • EP4053445B1 patent drawingFigure 2
  • EP4053445B1 patent drawingFigure 3

AI summary

Connection system for an opening (3, 3', 4) in a cylindrical pressure tank (1) with an internal liner (2) and a CFRP winding layer (100), wherein the liner (2) has at least one opening (3, 3', 4) and an annular indentation (20) around the opening (3, 3', 4), comprising: - a reinforcing ring (5) with a planar upper surface (5a), a planar lower surface (5b), a through bore (5c) and an edge (5f) tapering flat towards the outer circumference, wherein the reinforcing ring (5) can be arranged in the correspondingly shaped indentation (20) such that the collar (21) lies in its bore (5c) and is flush with the upper surface (5a), - a connection of the reinforcing ring (5) with the indentation (20) in the area of ​​the collar (21), - a closure means (8, 80, 800) for arrangement on the at least one opening (3, 3', 4) with an outer side (8a), an inner side (8b) and a cantilever area (9),wherein the cantilevered area (9) overlaps the reinforcing ring (5) in the assembled state and can be positively connected to it, and wherein the closure means (8, 80, 800) comprises functional means (11, 13), - seals (7) which can be arranged circumferentially on the planar upper surface (5a) and on the planar lower surface (5b) of the reinforcing ring (5), so that in the assembled state the opening (3, 3', 4) is sealed both between the liner (1) and the reinforcing ring and between the reinforcing ring (5) and the closure means (8, 80, 800), wherein the reinforcing ring (5) with its flatly tapered edge (5f) is dimensioned such that it transfers the pressure force acting on the opening (3, 3', 4) of a pressurized pressure tank (1) to the area overlapping it in the edge region (5f). CFRP winding layer (100) can dissipate.