Multi-Chamber Seal Layout for Lubricating Oil Leak Containment

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Solution Overview

Problem

Existing seal devices in propulsion machines of ships and tidal current generators are prone to leakage of lubricating oil to the outside due to failure of seal rings, where high-pressure lubricating oil can enter the primary annular chamber and be blown out, and external fluids can enter the equipment.

Innovation Solution

A seal device with a first seal part facing external fluid, a second seal part facing sealed fluid, and an intermediate seal part with a gas chamber and intermediate chamber, where the gas chamber has higher pressure than the external fluid and the intermediate chamber has lower pressure than the sealed fluid, preventing leakage by storing the sealed fluid in the intermediate chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-pressure lubricating oil is supplied to the secondary annular chamber to blow out air and prevent seawater entry, then sealing performance against seawater is improved, but leakage of lubricating oil to the outside may occur when seal rings fail

Engineering Contradiction:
Improvesealing performanceVSAvoidlubricating oil leakage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The sealing system is divided into multiple independent seal rings (first seal ring, second seal ring, third seal ring) arranged in sequence, creating separate sealing zones. This segmentation allows the system to maintain sealing function even if one seal ring fails, and prevents uncontrolled leakage by localizing potential failure points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The primary annular chamber acts as an intermediary chamber between the secondary annular chamber (containing high-pressure lubricating oil) and the external environment. When seal rings fail, this intermediate chamber captures the leaking lubricating oil, preventing it from directly reaching the outside while still maintaining the pressure differential needed for sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If seal rings are used to prevent fluid leakage, then sealing function is achieved, but complexity of the seal device increases due to multiple components and pressure control systems

Engineering Contradiction:
Improvesealing functionVSAvoidseal device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The multiple seal rings serve multiple functions: they provide sealing against both seawater and lubricating oil, create pressure zones for fluid control, and act as backup sealing elements for each other. This multi-functionality reduces the need for separate dedicated components for different sealing tasks.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The seal device structure nests multiple seal rings within the housing, with each seal ring positioned in sequence along the shaft. The primary annular chamber is nested between the seal rings, creating a compact layered structure where components are arranged concentrically and axially to maximize space utilization.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 seal device effectively prevents leakage of sealed fluids to the outside by storing them in the intermediate chamber with controlled pressure, ensuring reliable sealing and reducing the risk of fluid ingress or egress.

Implementation Method 1

a gas chamber is formed between the first seal part and the intermediate seal part, to which a gas having a higher pressure than the external fluid is supplied

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

an intermediate chamber is formed between the intermediate seal part and the second seal part, to which a gas having a lower pressure than the gas supplied to the gas chamber and having a lower pressure than the sealed fluid is supplied

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP3971432B1Use of a seal device
Publication Date: 2025.07.09 EAGLE INDS
  • EP3971432B1 patent drawingFigure 1
  • EP3971432B1 patent drawingFigure 2
  • EP3971432B1 patent drawingFigure 3

AI summary

Provided is a seal device capable of reliably preventing a sealed fluid from leaking to the outside of equipment. A seal device 1 is provided at a portion where relative rotation occurs between a first member 10 and a second member 2 that rotates relative to the first member 10. The seal device 1 includes first seal part 21 facing an external fluid W and second seal part 23 arranged in parallel to the first seal part 21 and facing a sealed fluid in an interior of equipment to prevent entry of the external fluid W and leakage of a sealed fluid. Intermediate seal part 22 is arranged in parallel to the first seal part 21 and the second seal part 23 between the first seal part 21 and the second seal part 23. A gas chamber 31 is formed between the first seal part 21 and the intermediate seal part 22, to which a gas having a higher pressure than the external fluid W is supplied. An intermediate chamber 32 is formed between the intermediate seal part 22 and the second seal part 23, to which a gas having a lower pressure than the gas supplied to the gas chamber 31 and having lower pressure than the sealed fluid is supplied.