Flat-Face Quick Coupling Sealing Against Water and Dust Ingress

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Solution Overview

Problem

Existing flat face screw couplings for pressurized fluids fail to maintain water and dust tightness in dirty environments, such as construction and demolition sites, leading to malfunctioning and damage due to dirt and water ingress, particularly at critical zones like the connection zone, stroke end abutment, and rear zone of the ring nut, causing oil leaks and reduced sealing effectiveness.

Innovation Solution

A flat face quick coupling design featuring toroidal sealing gaskets made of thermoplastic polyurethane (TPU) with specific profiles and counter-shaped seats on the safety ring nut, ensuring a robust seal against water and dust, and additional gaskets for enhanced sealing and wiping functions, tested to meet IP54 standards for protection against dust and water spray.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sealing elements (O-rings, metal elastic rings, nitrile rubber wipers) are used in flat face screw couplings, then the coupling can be manufactured and assembled, but water and dust ingress causes malfunctioning and damage in dirty environments

Engineering Contradiction:
Improvesealing effectivenessVSAvoidwater and dust ingress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter from traditional nitrile rubber to thermoplastic polyurethane (TPU), which maintains sealing effectiveness while resisting softening at high temperatures. It also changes the geometric parameter of the gasket profile to a toroidal shape with specific dimensions that optimize the seal against water and dust ingress.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite sealing gaskets made of thermoplastic polyurethane (TPU) material that combines the elasticity needed for sealing with resistance to thermal softening and chemical degradation, creating a multi-property material solution that addresses multiple failure modes simultaneously.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If way wipers are made of soft material (nitrile rubber) to perform wiping function, then they can conform to surfaces, but they soften at high temperatures and fail to seal properly

Engineering Contradiction:
Improvewiping functionVSAvoidthermal softening
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent changes the material parameter from nitrile rubber to thermoplastic polyurethane (TPU), which has a higher glass transition temperature and maintains its mechanical properties at elevated temperatures. This allows the gasket to perform wiping functions while resisting thermal softening up to 100°C and above.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the green band is configured with flat surfaces to minimize interference with ring nut sliding, then connection marking is achieved, but it does not guarantee seal against water and dust

Engineering Contradiction:
Improveconnection markingVSAvoidseal against water and dust
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent makes the green band serve multiple functions: it provides visual connection marking through its color and position, and simultaneously provides sealing against water and dust through its toroidal gasket profile made of TPU material. This eliminates the need for separate sealing components at this location.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If multiple sealing components are added to prevent water and dust ingress, then sealing effectiveness improves, but device complexity increases

Engineering Contradiction:
Improvewater and dust tightnessVSAvoidnumber of sealing components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple sealing functions into single toroidal gasket components positioned at critical locations. Each toroidal gasket simultaneously provides sealing against water, dust, and pressure differentials, eliminating the need for multiple separate sealing rings and wipers that would be required in traditional designs.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3569908B1Water and dust-tight quick coupling
Publication Date: 2023.04.26 FASTER SPA
  • EP3569908B1 patent drawingFigure 1~2
  • EP3569908B1 patent drawingFigure 3~4
  • EP3569908B1 patent drawingFigure 5~6A

AI summary

The present invention relates to a flat face screw quick coupling comprising a female half coupling which in turn comprises a main body comprising a front portion configured to house the front portion of a male half coupling in turn connectible to a hydraulic line. The quick coupling according to the present invention is characterised in that it is equipped with specific expedients and specifically devised gaskets that allow the coupling to be dust and water tight.