Sealing Ring with Pressure Equalization Bores

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Solution Overview

Problem

In hydraulic or pneumatic machinery, sealing devices experience high friction due to pressure differences between high-pressure and low-pressure sides, which increases contact forces and is undesirable, and they struggle to maintain sealing when pressure gradients change direction.

Innovation Solution

A sealing device with a sealing ring having an annular groove and bores for fluid communication between the sealing surface and the groove, along with a resilient O-ring, which equalizes pressure and reduces friction by eliminating pressure differences across the sealing surface, maintaining mechanical stability regardless of pressure gradient direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the width of the contact surface is increased to maintain sealing, then sealing reliability is improved, but friction and contact force increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoidcontact force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The sealing ring is segmented into multiple functional zones: a friction surface for sealing contact, an annular groove for pressure equalization, and bores for fluid communication. This segmentation allows the sealing function to be separated from the load-bearing function, enabling the contact surface to maintain sealing without excessive contact force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Fluid introduced through the bores acts as an intermediary to equalize pressure between the high-pressure and low-pressure sides of the sealing ring. This fluid pressure mediation reduces the pressure differential across the contact surface, thereby reducing contact force while maintaining sealing reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If the width of the contact surface is reduced to decrease friction, then friction is reduced, but sealing reliability deteriorates

Engineering Contradiction:
ImprovefrictionVSAvoidsealing reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention uses hydraulic or pneumatic principles by introducing fluid through bores into the annular groove to equalize pressure across the sealing ring. This fluid pressure system compensates for the reduced contact surface width, maintaining sealing reliability while minimizing friction through optimized contact geometry.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Force

If pressure equalization is implemented through bores, then friction is reduced, but device complexity increases

Engineering Contradiction:
ImprovefrictionVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The pressure equalization system is implemented locally within the sealing ring structure through strategically positioned bores and an annular groove, rather than requiring a complex external pressure control system. This localized approach minimizes device complexity while achieving friction reduction.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If a resilient ring is added to seal the annular groove, then sealing capability against bidirectional pressure gradients is improved, but device complexity increases

Engineering Contradiction:
Improvebidirectional sealing capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A resilient ring (flexible element) is installed in the annular groove to provide sealing against bidirectional pressure gradients. The flexibility of this thin ring allows it to adapt to pressure changes from either direction, providing versatile sealing capability with minimal additional complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

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 effectively reduces friction and maintains sealing integrity across varying pressure gradients, ensuring efficient operation in machinery with reciprocating or rotating movements by eliminating pressure differences across the sealing surfaces.

Implementation Method 1

one or more bores establishing fluid communication between the first side and the annular groove in the sealing surface. The fluid communication established by the bore equalises the pressure at the first side and in the annular groove

Methodology Applied
Scientific EffectFluid communication:

Implementation Method 2

a resilient ring such as an O-ring accommodated in the annular groove in the sealing surface. Such a sealing device functions symmetrically and seals against pressure gradients in either direction with the O-ring sealing the annular groove towards the low-pressure side

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3121490B1Sealing arrangement
Publication Date: 2019.04.03 TRELLEBORG SEALING SOLUTIONS DENMARK
  • EP3121490B1 patent drawingFigure 1
  • EP3121490B1 patent drawingFigure 2

AI summary

A sealing device comprising a sealing ring (31) for being accommodated in a groove (11) of the first machine part (10). The sealing ring has a sealing surface (32) for contacting the second machine part (20) and an annular groove (33) in the sealing surface with sealing surface portions (32a, 32b) on respective sides of the groove. First and second opposed sides (35, 36) extend transversely to the sealing surface. One or more bores (37, 38) establish fluid communication between one or both opposed sides and the annular groove in the sealing surface. An O-ring (34) is arranged in the annular groove and seals the bores on the low pressure side of the sealing device.