Wave Power Device Hydraulic Self-Centering

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Solution Overview

Problem

Existing wave power devices face challenges in efficiently extracting energy from the horizontal component of water waves due to irregular wave patterns, leading to drift and increased forces that can damage the system, and require costly mechanical springs for self-centering, which are prone to fatigue in marine environments.

Innovation Solution

A wave power device with symmetrically arranged hydraulic rams that adjust their effective hydraulic area stepwise to maintain self-centering of the effector, reducing the risk of damage from high waves and eliminating the need for return springs by using the hydraulic rams to manage forces and stabilize the effector's movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical springs are used for self-centering the effector, then the system can maintain center position, but the system becomes heavier, more costly, and more prone to fatigue failure

Engineering Contradiction:

Improveresistance to fatigue failureVSAvoidweight of self-centering mechanism

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces mechanical springs with a hydraulic self-centering mechanism. The hydraulic ram uses fluid pressure and a piston-cylinder arrangement to provide the self-centering force, eliminating the need for mechanical springs and their associated support structures. This substitution reduces weight while maintaining reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention employs a hydraulic system where a piston moves within a cylinder filled with hydraulic fluid. The hydraulic pressure differential created during the effector's movement automatically centers the effector without requiring mechanical springs. The hydraulic fluid transmits force efficiently, providing reliable self-centering without the fatigue issues of mechanical springs.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Productivity

If the effector travel length is increased to capture more wave energy, then energy extraction improves, but the system becomes heavier and costlier

Engineering Contradiction:

Improveenergy extraction efficiencyVSAvoidweight of effector system

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The hydraulic self-centering mechanism allows the effector to dynamically adjust its position and travel distance based on wave conditions. The variable effective hydraulic area enables the system to optimize the stroke length automatically, capturing maximum energy from varying wave amplitudes without requiring an excessively long fixed travel length, thus reducing overall system weight.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the effective hydraulic area parameter during the effector's travel. By varying the hydraulic area, the system can maintain optimal force multiplication across different stroke lengths, allowing efficient energy extraction with shorter, lighter effectors rather than requiring long travel distances.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If the effector is constrained to prevent drift, then system stability improves, but large forces build up when wave flow is discontinued

Engineering Contradiction:

Improveeffector position stabilityVSAvoidforce on effector during wave discontinuation

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The hydraulic self-centering mechanism provides continuous feedback control. As the effector moves from center position, the hydraulic piston automatically generates a restoring force that pushes it back to center. This feedback mechanism maintains stability without rigid constraints, allowing the effector to move freely while preventing excessive drift, and naturally accommodating wave flow discontinuations without building up large forces.

Inventive Principle:

Principle #23Feedback

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 enables efficient energy extraction from water waves while minimizing unintended loads and extending the system's durability by avoiding the need for costly mechanical springs, making the system lighter, cheaper, and more robust against fatigue.

Implementation Method 1

at least two hydraulic rams preferably being symmetrically arranged around each effector 11 along the length axis of the substantially stationary member 2

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

the sections together enclose a sealed space, having a volume which are decreasing or increasing when the sections slide into and out of each other respectively

Methodology Applied

Scientific EffectHydraulic fluid compression: Compression

Data Source

PatentUS11333124B2Wave power device

Publication Date: 2022.05.17 WAVEPISTON

AI summary

The present invention relates to a wave power device for extracting energy from water waves. The waver power device comprise a reference structure and effectors moving relative to the reference structure. The effectors are connected to two hydraulic rams, symmetrically positioned around each effector. The hydraulic rams have an effective hydraulic area which is stepwise increased as the length of the hydraulic rams are compressed and stepwise increased as the length of the hydraulic rams are increased.