Rotary Face Seal Magnetic Loading Without Spring Fatigue

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Solution Overview

Problem

Existing mechanical rotary face seals face issues with spring mechanism variability due to natural frequency and material fatigue, leading to compromised performance and service life, especially under shock, vibration, and temperature extremes, and are limited by material selection and production yield uncertainties.

Innovation Solution

The rotary face seal employs magnetic technology with a single pole tubular magnetic band attached to the outside diameter of the rotary annular ring, providing consistent load and eliminating eddy currents, replacing the traditional spring mechanism with axial or radial magnet orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring mechanism is used for mechanical load, then positive contact against the rotary mating surface is provided, but load variation occurs due to natural frequency, shock, vibration, and material fatigue

Engineering Contradiction:

Improveseal contact consistencyVSAvoidspring load variation

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent replaces the mechanical spring loading system with a magnetic field-based loading system. Magnets are positioned to create a magnetic field that exerts force on the seal ring, providing consistent loading without the variability inherent in mechanical springs. This substitution eliminates the problems of natural frequency resonance, shock sensitivity, and material fatigue that plague spring mechanisms.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of force application from mechanical elastic deformation (springs) to magnetic field interaction. By adjusting magnetic field strength and distribution, consistent and controllable loading is achieved without the dynamic variability characteristic of mechanical spring systems under vibration and shock conditions.

Inventive Principle:

Principle #35Parameter changes

2Force

If magnets are installed in a housing, then magnetic pull loading is achieved, but eddy currents are generated during rotation

Engineering Contradiction:

Improvemagnetic pull loadingVSAvoideddy currents

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the magnets from the stationary housing and relocates them to rotate with the seal ring. This extraction and relocation strategy fundamentally changes the reference frame of the magnetic field, allowing it to rotate with the seal and eliminate relative motion between the magnetic field and the seal ring, thereby eliminating eddy current generation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of having the magnetic field stationary and the seal ring rotate through it (which generates eddy currents), the patent inverts the approach by making the magnetic field rotate with the seal ring. This inversion eliminates the harmful eddy currents while maintaining the beneficial magnetic pull loading effect.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If spring mechanism is used, then material selection is restricted, but production yield rates are uncertain

Engineering Contradiction:

Improvematerial selection flexibilityVSAvoidproduction yield rate

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the loading mechanism from material-dependent spring properties to field-based magnetic forces. This parameter change allows the use of diverse materials for the seal ring and mating surfaces without being constrained by spring material requirements, while the magnetic field provides consistent, predictable forces that improve manufacturing precision and yield rates.

Inventive Principle:

Principle #35Parameter changes

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

This design enhances seal performance and service life by minimizing load variation and fatigue issues, allowing for improved reliability and flexibility in material selection while avoiding eddy currents and installation sensitivities.

Implementation Method 1

uses magnetic technology attached to the outside diameter of the rotary ring which is attached to the shaft that does not produce eddy currents because it is of a single pole design

Methodology Applied

Scientific EffectMagnetic pull: Magnetism

Implementation Method 2

does not produce eddy currents because it is of a single pole design

Methodology Applied

Scientific EffectEddy currents elimination: Eddy Currents

Data Source

PatentUS11441685B2Rotary face seal with magnetic puller loading

Publication Date: 2022.09.13 MAGNETIC SEAL LLC

AI summary

The rotary face seal with magnet loading replaces known spring mechanisms with magnetic technology that provides a consistent load with minimal variation, which is not affected by natural frequency and material fatigue due to cyclic loading. This improves seal performance and service life. The tubular magnetic ring is advantageous because it replaces existing seals within stationary cartridge with a puller type magnetic assembly design that results with the stationary cartridges being an exact exchange. The use of magnetic technology attached to the outside diameter of the rotating mating ring, which is attached to the shaft, that does not produce eddy currents because it is of a single pole configuration. The single pole magnetic assembly design is achieved by either axial or radial magnet orientation, such as in the form of a tubular magnetic band locating in a circumferential notch in the rotating mating ring.