Inflatable Sail With Symmetrical Profile

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Solution Overview

Problem

Inflatable sails in existing technologies face issues with air leaks and insufficient inflation, especially in weak or non-existent winds, and lack the ability to maintain a consistent aerodynamic profile across varying wind conditions.

Innovation Solution

An inflatable sail design with two sealed surfaces forming a cavity, equipped with an air injection system, such as a turbine, to maintain a symmetrical profile and regulate pressure, ensuring consistent performance in all wind conditions, and the option to deflate for storage or reducing sail area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sail is initially inflated without continuous air injection, then the structure is simple and energy consumption is low, but the sail cannot compensate for air leaks and cannot maintain sufficient inflation in light or non-existent winds

Engineering Contradiction:
Improvesail inflation maintenanceVSAvoidair injection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sail is pre-inflated to a sufficient pressure level before operation begins. This preliminary inflation ensures that the sail maintains its aerodynamic profile even when wind conditions are light or non-existent, and provides a buffer against air leaks during operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the sail's own structure and the available wind (when present) to maintain its inflation. The symmetrical profile design allows the sail to self-regulate its aerodynamic characteristics without requiring complex active control systems, reducing overall system complexity while maintaining reliability

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the sail is passively inflated by continuously introducing air from wind, then the structure is simple, but the sail is not sufficiently inflated at the start, especially when wind is light or non-existent

Engineering Contradiction:
Improvesail inflationVSAvoidsail performance in light wind
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The sail is pre-inflated to operational pressure levels before the vehicle begins movement or before light wind conditions occur. This ensures immediate sail performance is available without delay, and the sail maintains its profile even when passive wind inflation would be insufficient

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the pressure parameter within the sail cavity to optimize performance. By maintaining pressure within a specific range (10-500 Pa as indicated in the patent), the sail achieves both ease of operation and maintained productivity across varying wind conditions

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the sail has an asymmetrical profile optimized for one direction, then aerodynamic performance in that direction is improved, but the sail cannot operate indifferently in both directions of advancement

Engineering Contradiction:
Improvebidirectional operationVSAvoidaerodynamic profile optimization
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry in a controlled manner by using symmetrical profiles that can adapt to different operational directions. The symmetrical design allows the sail to present the optimal aerodynamic surface to the wind regardless of the direction of advancement, achieving bidirectional operation without sacrificing aerodynamic efficiency

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The sail profile dynamically adapts to operational conditions through pressure regulation. The inflatable structure allows the sail to maintain its optimal aerodynamic shape while operating in different directions, with the pressure system ensuring consistent profile maintenance across varying conditions

Inventive Principle:
Principle #15Dynamics

4Stability of the object's composition

If high pressure is used to maintain sail shape in all conditions, then sail profile stability is improved, but energy consumption increases

Engineering Contradiction:
Improvesail profile stabilityVSAvoidair injection energy
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The system changes the pressure parameter dynamically based on operational conditions. Pressure is maintained within an optimized range (10-500 Pa) that is sufficient to maintain sail profile stability but low enough to minimize energy consumption. The pressure level is adjusted according to wind conditions and operational requirements

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Rather than maintaining maximum pressure continuously, the system applies partial pressure sufficient for profile stability. The air injection operates at low pressure levels that provide just enough inflation to maintain the aerodynamic shape, avoiding excessive energy consumption while ensuring profile stability

Inventive Principle:
Principle #16Partial or excessive 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

The design ensures consistent aerodynamic performance in both directions and at various wind speeds, reducing energy consumption and maintaining sail shape, even in zero winds, while allowing for easy storage and adjustment.

Implementation Method 1

a conduit arranged between the inside and the outside of the cavity and means for injecting air into the latter

Methodology Applied
Scientific EffectAir injection:

Implementation Method 2

The air injection means (e.g. a turbine) operate continuously, so as to permanently inject a flow of air through at least one orifice between the 2 adjacent surfaces

Methodology Applied
Scientific EffectTurbine: Turbine

Implementation Method 3

the aerodynamic forces produced by the flow of air around the profile are absorbed along the rigging, at a location located at the level of the transverse elements, not at the front of the profile, but substantially at the center of aerodynamic thrust

Methodology Applied
Scientific EffectAerodynamic forces: Aerofoil

Data Source

PatentEP3475164B1Sail propulsion element comprising an inflatable sail with a symmetrical profile
Publication Date: 2021.06.02 NEXT TECH SARL
  • EP3475164B1 patent drawingFigure 1~2
  • EP3475164B1 patent drawingFigure 3~4
  • EP3475164B1 patent drawingFigure 5A~5D

AI summary

A sail propulsion element comprising an inflatable sail (2) consisting essentially of two substantially sealed adjacent surfaces (9, 10) linked to each other on the perimeter of same, thus together forming a recess (8); the element further comprising a conduit (11) disposed between the inside and the outside of the recess (8) and means for injecting air into the latter; characterised by the fact that the sail (2), once inflated, has a profile that remains permanently symmetric, regardless of the movement of the element, or the direction or strength of the wind.