Annular Seal Point Protrusions Prevent Distributor Clogging

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Solution Overview

Problem

Annular seals, such as O-rings, tend to adhere to the walls of distributors and aggregate together due to surface tension in lubricated seals and static electricity in non-lubricated seals, leading to clogging and increased maintenance needs, which hampers automatic dispensing and user assembly efficiency.

Innovation Solution

The introduction of point protrusions on the contact surface of the seals, which are non-annular and have a negligible influence on the total surface area, reduces contact with the distributor and other seals, preventing aggregation and clogging. These protrusions are strategically placed on the contact surface and can be shaped hemispherical, pyramidal, conical, or frustoconical, with specific dimensions to ensure separation and maintain sealing functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If seals are lubricated to reduce assembly effort, then ease of operation is improved, but the seals adhere to distributor walls and aggregate together due to surface tension, worsening productivity and reliability

Engineering Contradiction:
Improveassembly effortVSAvoiddistribution rate
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent applies local quality by creating point protrusions at specific locations on the seal surface. These protrusions concentrate the contact area to discrete points rather than allowing broad surface contact. The protrusions have specific geometric characteristics (height between 0.2-15% of seal thickness, spherical or conical shape) that locally modify the interaction with the distributor, preventing capillary adhesion while maintaining the overall lubricated surface for easy assembly.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If seals are lubricated to reduce assembly effort, then ease of operation is improved, but clogging of distributors occurs, worsening maintenance needs and reliability

Engineering Contradiction:
Improveassembly effortVSAvoiddistributor clogging
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The point protrusions create localized contact zones that prevent the lubricant from forming continuous capillary bridges between seals and distributor walls. By concentrating contact to discrete points with controlled geometry, the lubricant cannot adhere seals to the distributor surface, eliminating clogging while preserving the lubricated assembly advantage.

Inventive Principle:
Principle #3Local quality

3Reliability

If non-lubricated seals are used to avoid clogging, then distributor reliability is improved, but electrostatic attraction causes seals to aggregate and adhere to walls, worsening productivity

Engineering Contradiction:
Improvedistributor cloggingVSAvoiddistribution rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The point protrusions create localized mechanical contact points that dominate the interaction between seals and distributor, overriding electrostatic forces. The concentrated geometric features provide sufficient mechanical separation and contact control to prevent electrostatic aggregation, enabling reliable non-lubricated dispensing with maintained productivity.

Inventive Principle:
Principle #3Local quality

4Productivity

If point protrusions are added to seal surface to prevent aggregation, then productivity is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvedistribution rateVSAvoidmold complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The point protrusions are integrated into the seal manufacturing process itself, forming during molding. The mold cavities pre-form the protrusion geometry (spherical or conical shapes with specified heights) as part of the seal fabrication, rather than requiring subsequent machining or assembly operations. This preliminary formation of the anti-aggregation features maintains manufacturing efficiency.

Inventive Principle:
Principle #10Preliminary 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 use of point protrusions allows for efficient automatic dispensing without clogging, maintaining high distribution rates and reducing maintenance needs, as demonstrated by improved dispensing rates and reduced adhesion to distributor surfaces over time.

Implementation Method 1

For lubricated seals, these phenomena are due to the surface tension of the lubricant used which generates capillary forces between the seals and/or the walls of the distributor.

Methodology Applied
Scientific EffectCapillary forces: Capillary Action

Implementation Method 2

For non-lubricated seals, these phenomena are due to the fact that friction between the seals and/or with the walls of the distributor charges the seals with static electricity. The gaskets stick together and/or adhere to the walls of the dispenser by electrostatic attraction.

Methodology Applied
Scientific EffectElectrostatic attraction: Electrostatics

Data Source

PatentEP2713081B1Ring joint and mould for manufacturing such a joint
Publication Date: 2015.09.16 LE JOINTS FRANCAIS SA
  • EP2713081B1 patent drawingFigure 1~8
  • EP2713081B1 patent drawingFigure 9~11

AI summary

The invention aims to provide a lubricable annular seal that allows for automatic dispensing in dispensers without the risk of clogging the dispensers or adhering to other seals. To this end, the invention provides an annular seal (20) of a defined thickness, made of elastically deformable material, comprising a sealing plane at mid-thickness and an axis of revolution perpendicular to the sealing plane, and having: • an "inner" surface, facing the axis of revolution, extending over a height of between 1/6 and 22/50 of the thickness on either side of the sealing plane, and • a "contact" surface extending over the remainder of the seal. The seal is characterized in that it comprises, on the contact surface, at least one point protrusion (21).