Floating Ring Seal With Magnetic Alignment for Long-Life Shaft Sealing

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Solution Overview

Problem

Conventional seal devices for rotating fluid machines, such as pumps, face issues with surface roughening and anchoring of the seal ring and plate springs, leading to loss of automatic aligning operation and improper sealing over time. Additionally, the assembly process is time-consuming and requires careful compression of plate springs.

Innovation Solution

A seal device utilizing a floating ring with contactless alignment, achieved through a magnetic repulsion force between magnets in the housing and the floating ring. This design maintains automatic aligning of the seal ring, ensures proper clearance between the rotation shaft and the seal ring, and provides a vibration damping function, while simplifying the assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plate springs are used to support the seal ring, then the seal ring can be positioned and aligned, but surface roughening and anchoring occur at contact portions over time, causing loss of automatic aligning operation

Engineering Contradiction:
Improveautomatic aligning operationVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces the mechanical contact-based plate spring support system with a magnetic field-based support system. Magnets are embedded in the seal ring to provide levitation and alignment forces, eliminating direct mechanical contact between the seal ring and plate springs. This substitution prevents surface roughening and anchoring, maintaining reliable automatic aligning operation throughout the service life.

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

Solution Approach 2:

The patent changes the physical state of the support force from mechanical contact force to magnetic field force. By embedding magnets in the seal ring, the support and alignment functions are achieved through magnetic fields rather than direct mechanical contact, fundamentally changing the interaction mechanism to prevent wear and maintain long-term reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If plate springs are installed in the retainer first, then the seal ring can be supported, but temporary compression is required to ensure gap for inserting the seal ring, making assembly time-consuming

Engineering Contradiction:
Improveassembly processVSAvoidassembly time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The magnetic support system eliminates the need for mechanical compression during assembly. The magnets embedded in the seal ring automatically provide levitation and alignment forces, allowing the seal ring to be installed without compressing plate springs or ensuring gaps, thereby simplifying the assembly process and reducing assembly time.

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

3Reliability

If the seal ring is tightly sealed against the housing, then proper sealing is achieved, but the seal ring cannot follow movement of the rotation shaft, leading to contact and damage

Engineering Contradiction:
Improvesealing operationVSAvoidfollowability of shaft movement
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The magnetic field-based support system replaces mechanical contact, allowing the seal ring to follow shaft movement through magnetic attraction to the rotation shaft while maintaining sealing through magnetic repulsion from the housing. This dual magnetic interaction enables both tight sealing and adaptability to shaft movement.

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

Solution Approach 2:

The patent makes the seal ring dynamically responsive to shaft movement by using magnetic attraction to the rotation shaft. The seal ring can dynamically adjust its position to follow shaft movement while maintaining the sealing function through magnetic repulsion from the housing, achieving both sealing reliability and followability.

Inventive Principle:
Principle #15Dynamics

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 maintains the automatic aligning operation of the seal ring over long durations, ensures optimal clearance and sealing performance, reduces vibration of the rotation shaft, and facilitates easier assembly by eliminating the need for direct contact and compression of components.

Implementation Method 1

the aligning means includes a first magnet arranged in the housing, the first magnet having a magnetic pole face directed in the radial direction, and a second magnet arranged in the floating ring, the second magnet having a magnetic pole face directed in the radial direction

Methodology Applied
Scientific EffectMagnetic repulsion force: Magnetism

Implementation Method 2

By the wedge effect (effect of dynamic pressure generated in a wedge portion) generated between an inner peripheral face of the seal ring 41 and the sleeve 44 of the rotation shaft 45

Methodology Applied
Scientific EffectWedge effect: Wedge

Implementation Method 3

the Lomakin effect (aligning effect by flow losses of a fluid between surfaces of a seal ring and a shaft at the time of generation of a seal pressure difference)

Methodology Applied
Scientific EffectLomakin effect:

Data Source

PatentEP3587874B1Seal device
Publication Date: 2025.04.02 EAGLE INDS
  • EP3587874B1 patent drawingFigure 1
  • EP3587874B1 patent drawingFigure 2
  • EP3587874B1 patent drawingFigure 3

AI summary

The present invention is to provide a seal device in which an automatic aligning operation of a seal ring is maintained even upon running for a long time, a clearance between a rotation shaft and the seal ring can be properly held, and a sealing operation by the seal ring and a vibration damping function can be exerted. A seal device (10) that seals between a housing (11) and a rotation shaft (20) passing through the housing (11) includes a floating ring (15) arranged with a gap h with respect to the rotation shaft (20), and the floating ring (15) includes an aligning means (18) that contactlessly aligns a position of the floating ring (15).