Gas-Lubricated Slide Ring Seal With Axial Gap Anti-Fouling

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Solution Overview

Problem

Gas-lubricated mechanical seals in compressors are prone to contamination by solid particles, which reduces their service life due to the inability to effectively prevent dirt from reaching the sealing gap between rotating and stationary seal rings.

Innovation Solution

A mechanical seal arrangement with a face seal, prestressing device, fluid chamber, axial gap, antechamber, and protective edges is designed to prevent solid particles from entering the sealing gap, utilizing centrifugal forces and radial gaps to enhance contamination protection and maintain a low pressure environment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional mechanical seal is used without additional protective structures, then the design remains simple, but solid particles can easily reach the sealing gap and reduce service life

Engineering Contradiction:
Improveservice lifeVSAvoiddesign complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The seal housing is segmented into multiple functional zones: a first axial gap positioned upstream of the sealing gap, a second axial gap downstream, and a pre-chamber. These segmented structures work together to create a multi-stage filtration system that progressively removes particles from the gas flow before it reaches the critical sealing interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first and second axial gaps act as intermediary zones between the contaminated gas supply and the clean sealing gap. These gaps serve as buffer regions where particles can be trapped and removed by centrifugal forces, preventing direct contact between contaminants and the sliding surfaces of the mechanical seal.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the axial gap is positioned close to the sealing gap to maximize protection, then contamination protection is improved, but the risk of particle ingress through the gap increases

Engineering Contradiction:
Improvecontamination protectionVSAvoidsealing effectiveness
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

Different regions of the seal assembly have different functional qualities: the axial gaps are designed with larger dimensions to trap particles, while the sealing gap itself is maintained with precise, tight tolerances to ensure effective sealing. The pre-chamber provides a transition zone that prepares the gas flow for entry into the sealing interface.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The solution moves the particle trapping function from the radial sealing dimension to the axial dimension by introducing axial gaps perpendicular to the sealing gap. This dimensional separation allows particle removal to occur in a different spatial plane, preventing particles from reaching the critical radial sealing interface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the mechanical seal operates at high rotational speeds, then sealing performance is improved, but centrifugal forces may still allow particles to reach the sealing gap

Engineering Contradiction:
Improvesealing performanceVSAvoidparticle ingress
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The axial gaps and pre-chamber create a preliminary defense mechanism that acts before the gas flow reaches the sealing gap. By positioning these protective structures upstream, particles are trapped and removed in advance, preventing them from reaching the sealing interface regardless of rotational speed.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The mechanical design preliminarily prepares the gas flow by forcing it through the axial gaps and pre-chamber before it can enter the sealing gap. This preliminary action of particle trapping occurs upstream, ensuring that only cleaned gas reaches the sealing interface during operation.

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 solution significantly extends the service life of mechanical seals by effectively preventing solid particles from reaching the sealing gap, ensuring safer operation and reduced contamination, even during axial movements and thermal expansion.

Implementation Method 1

the rotation generates centrifugal forces primarily outwards, which fling dirt particles and the like away from the axial gap

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

Gas-lubricated mechanical seals are used, for example, in compressors to seal a compressor drive shaft. A gaseous fluid, such as air or nitrogen, is used as the sealing medium for the sealing gap between the rotating and stationary sliding rings

Methodology Applied
Scientific EffectGas lubrication: Air Lubrication

Data Source

PatentEP3701173B1Gas-lubricated slide ring seal with improved Anti-fouling protection
Publication Date: 2023.03.15 EAGLEBURGMANN GERMANY GMBH &CO KG
  • EP3701173B1 patent drawingFigure 1
  • EP3701173B1 patent drawingFigure 2
  • EP3701173B1 patent drawingFigure 3

AI summary

The invention relates to a gas-lubricated slide ring seal arrangement which uses a gaseous fluid as barrier medium, comprising: a slide ring seal with a rotating slide ring (2) and with a static slide ring (3) which, between them, define a sealing gap (4), a preload device (5) which preloads the static slide ring (3) in the direction of the rotating slide ring (2), a fluid chamber (6) to which the gaseous fluid can be fed, a first slide ring carrier (20) for holding the rotating slide ring (2), wherein the first slide ring carrier (20) has a first axial surface (21), a second slide ring carrier (30) for holding the static slide ring (3), wherein the second slide ring carrier (30) has a second axial surface (31), wherein the second slide ring (30) and the static slide ring (3) are arranged so as to be jointly displaceable on a displacement surface (32) in an axial direction (X-X), an axial gap (7) which is delimited by the first axial surface (21) and the second axial surface (31), and a pre-chamber (8) which is formed at the sealing gap (4) of the slide ring seal and which is connected by the axial gap (7) to the fluid chamber (6).