Liquid-Sealed Actuator for Non-Contact Wave Generation

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Solution Overview

Problem

Existing wave generation systems face challenges in generating large waves consistently and efficiently, leading to mechanical wear and energy inefficiency, which also affects other applications involving liquid transfer.

Innovation Solution

A non-contact liquid sealing actuator system comprising an inner and outer shaft with a sealing ring and a mass, where a pressure source injects pressurized fluid to lift the mass, generating waves in an external liquid with a backpressure opposing the pressure, allowing for oscillation and wave generation without contact, thus reducing friction and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional contact-based sealing mechanisms are used in wave generation systems, then mechanical sealing is achieved, but mechanical wear and friction increase significantly

Engineering Contradiction:
Improvesealing effectivenessVSAvoidmechanical wear resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a liquid medium as an intermediary between the moving shaft and stationary housing, replacing direct mechanical contact seals with liquid-based sealing. The liquid sealant fills the gap between components, providing sealing through fluid pressure and surface tension rather than mechanical friction, thereby eliminating wear while maintaining seal integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces traditional mechanical sealing systems (such as rubber seals, brush seals, or contact bearings) with a non-contact liquid sealing mechanism. The liquid sealant is pumped into the actuator chamber, creating a pressure-based seal that prevents leakage without requiring physical contact between moving and stationary parts, thus eliminating mechanical wear.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Force

If large forces are applied to generate large waves consistently, then wave generation effectiveness improves, but energy consumption increases significantly

Engineering Contradiction:
Improvewave generation forceVSAvoidenergy consumption
Core Design Contradiction:
ForceVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic oscillation of the actuator shaft to generate waves, rather than continuous application of large forces. The shaft oscillates back and forth in a controlled periodic manner, creating efficient wave patterns that propagate through the water. This periodic action reduces peak force requirements and optimizes energy utilization compared to continuous force application.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention changes the operational parameters of the wave generation system by using controlled oscillation frequency and amplitude variations. By adjusting these parameters, the system can generate large waves efficiently without requiring proportionally large continuous forces, thereby reducing overall energy consumption while maintaining wave generation effectiveness.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If traditional mechanical wave generation systems are used, then wave generation capability is achieved, but mechanical wear and maintenance requirements increase

Engineering Contradiction:
Improvewave generation capabilityVSAvoidsystem lifespan
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The liquid sealant acts as a mediator that protects the mechanical components from direct contact and wear. It fills the clearance between the oscillating shaft and housing, preventing debris accumulation and reducing friction, thereby extending the lifespan of mechanical components while maintaining wave generation productivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

By replacing contact-based mechanical sealing with non-contact liquid sealing, the system eliminates the primary source of mechanical wear. The liquid seal provides a protective barrier that reduces component degradation, thereby extending system operational life and reducing maintenance requirements while preserving wave generation capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If contact-based sealing rings are used in the actuator system, then sealing is achieved, but friction and energy loss increase

Engineering Contradiction:
Improvesealing integrityVSAvoidfriction loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The liquid sealant serves as an intermediary fluid that creates a pressure-based seal between the oscillating shaft and housing without requiring physical contact. This liquid intermediary maintains sealing integrity through hydrostatic pressure and surface tension effects, eliminating the friction losses associated with contact-based sealing rings.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention substitutes traditional mechanical sealing rings with a non-contact liquid sealing system. The liquid sealant is introduced into the actuator chamber and maintains sealing through fluid pressure rather than mechanical contact, thereby eliminating friction losses and associated energy waste while preserving sealing integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system achieves robust and efficient wave generation with reduced mechanical wear and energy consumption, suitable for various applications including surfing, irrigation, and marine environments, while maintaining low noise levels.

Implementation Method 1

a pressure source that can inject a pressurised fluid into the hollow outer shaft, thereby applying a pressure against both the first end of the inner shaft and the at least one sealing ring that assists in lifting the mass

Methodology Applied
Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

the system is at least partially immersed in an external liquid such that the at least one sealing ring is submerged in the external liquid and a head of the external liquid above the at least one sealing ring defines a backpressure in the annular seal gap that opposes the pressure applied by the pressure source

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Increase

Implementation Method 3

the mass defines a central wave device that can oscillate vertically in the external liquid... the central wave device can generate waves in the external liquid

Methodology Applied
Scientific EffectWave generation: Wave Power

Data Source

PatentEP3544702B1Non-contact liquid sealing actuator system
Publication Date: 2021.09.15 SURF LAKES HOLDINGS LTD
  • EP3544702B1 patent drawingFigure 1~2
  • EP3544702B1 patent drawingFigure 3~4
  • EP3544702B1 patent drawingFigure 5~6

AI summary

A liquid sealing actuator system enables use in a non-contact or low-friction manner. The system includes: an inner shaft having a first end; a hollow outer shaft having a first end that receives the first end of the inner shaft; at least one sealing ring positioned adjacent an internal surface of the hollow outer shaft, wherein the at least one sealing ring has an outer diameter that is less than an inner diameter of the outer shaft, thereby defining an annular seal gap; a mass attached to a distal end of either the inner shaft or the outer shaft; and a pressure source that injects a pressurised fluid into the hollow outer shaft, thereby applying a pressure against both the first end of the inner shaft and the at least one sealing ring that assists in lifting the mass; wherein the system is at least partially immersed in an external liquid such that the at least one sealing ring is submerged in the external liquid and a head of the external liquid above the at least one sealing ring defines a backpressure in the annular seal gap that opposes the pressure applied by the pressure source.