Floating Ring Seal With Dynamic Pressure Grooves

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Solution Overview

Problem

Conventional sealing devices with floating rings face issues in maintaining concentricity with rotating shafts, leading to eccentric assembly and increased fluid leakage due to larger gap requirements, which results in inefficient sealing performance.

Innovation Solution

The implementation of inversely directed dynamic pressure generation grooves on the inner peripheral surface of the floating ring to push sealed fluid back upstream, reducing leakage and aiding in center alignment with the rotating shaft, combined with barrier fluid supply holes for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gap between the floating ring and rotating shaft is increased to prevent contact, then reliability is improved, but sealing performance deteriorates due to increased fluid leakage

Engineering Contradiction:
Improveprevention of contact between floating ring and rotating shaftVSAvoidfluid leakage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs hydrodynamic pressure generation through specially designed grooves on the floating ring surface. These grooves generate dynamic pressure in the fluid film between the floating ring and rotating shaft, creating a pressure distribution that maintains separation and prevents contact while minimizing leakage. The hydraulic action of the fluid itself is utilized to achieve both reliability and sealing performance simultaneously.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical parameters of the fluid film by introducing grooves with specific geometric parameters (depth, width, orientation). These parameter changes create optimal pressure distribution in the fluid film, allowing the system to maintain both adequate gap for reliability and minimal leakage by optimizing the hydrodynamic conditions rather than simply increasing the gap size.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional floating ring structures are used, then device complexity is reduced, but manufacturing precision deteriorates due to difficulty in assembling concentricity

Engineering Contradiction:
Improvesimplicity of floating ring structureVSAvoidconcentricity assembly precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The floating ring is equipped with self-aligning grooves that automatically generate hydrodynamic pressure to center the ring on the rotating shaft during operation. This self-service mechanism eliminates the need for precise pre-alignment or complex external alignment mechanisms, allowing the structure to self-correct assembly errors and maintain concentricity automatically through fluid pressure distribution.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces dynamic grooves that generate time-varying hydrodynamic pressure as the floating ring rotates. This dynamic pressure generation creates automatic centering forces that actively maintain concentricity during operation, transforming a static alignment problem into a dynamic self-correcting system that adapts to operational conditions.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If conventional floating ring structures are used, then device complexity is reduced, but adaptability deteriorates due to inability to track shaft eccentricity

Engineering Contradiction:
Improvesimplicity of supporting structureVSAvoidtracking of shaft eccentricity
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The grooves on the floating ring are designed to dynamically generate hydrodynamic pressure that automatically adapts to shaft eccentricity and deflection. As the shaft position changes, the pressure distribution in the grooves shifts accordingly, creating restoring forces that track and accommodate eccentricity without requiring complex active control systems or adjustable mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hydrodynamic pressure generated in the grooves provides continuous feedback about the relative position between the floating ring and rotating shaft. This pressure feedback automatically adjusts the floating ring position to maintain optimal clearance and concentricity, enabling the simple structure to adapt to changing shaft conditions through inherent fluid-mechanical feedback mechanisms.

Inventive Principle:
Principle #23Feedback

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 configuration allows for a smaller gap between the floating ring and rotating shaft, improving sealing performance, reducing leakage, and maintaining dynamic stability during start-up, while minimizing the risk of contact between the ring and shaft.

Implementation Method 1

inversely directed dynamic pressure generation grooves for creating an action whereby a sealed fluid is pushed back upstream

Methodology Applied
Scientific EffectHydrodynamic pressure: Pressure Gradient

Implementation Method 2

A water film formed in a gap a between an inner peripheral surface of the floating ring 45 and an outer peripheral surface of the rotating shaft 40 allows the floating ring 45 to avoid contact with the rotating shaft 40

Methodology Applied
Scientific EffectHydrodynamic lubrication: Lubrication

Data Source

PatentEP2636931B1Seal device
Publication Date: 2019.08.07 EAGLE INDS
  • EP2636931B1 patent drawingFigure 1
  • EP2636931B1 patent drawingFigure 2
  • EP2636931B1 patent drawingFigure 3(a)~3(b)

AI summary

{Technical Problem} An object of the present invention is to reduce the amount of leaking of a sealed fluid and to match together the center of a floating ring and the center of a rotating shaft. {Solution to Problem} A sealing device provided with a floating ring between an outer periphery of a rotating shaft and an inner periphery of a casing is characterized in that a plurality of inversely directed dynamic pressure generation grooves for creating an action whereby a sealed fluid attempting to leak out is pushed back are provided in the circumferential direction to the inner peripheral surface of the floating ring.