Fluid Valve Seal Assemblies with Scraper Segmentation

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Solution Overview

Problem

Existing seal assemblies for fluid valves are prone to contamination, which reduces the useful life of the seals and increases maintenance needs due to the ingress of particulates and contaminants at the dynamic sealing surface, leading to fluid leakage.

Innovation Solution

The proposed seal assembly includes a first and second scraper positioned on either side of the seal to prevent contaminants from entering the dynamic sealing surface and seal gland, with a spacer between the seals to maintain their positions and prevent loading, thereby extending the seal's life and preventing fluid leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal is used to prevent fluid leakage between the cage and flow control member, then sealing reliability is improved, but contaminates erode the seal during movement, reducing seal life and increasing maintenance needs

Engineering Contradiction:
Improvesealing reliabilityVSAvoidseal life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The seal assembly is segmented into multiple functional components: a primary seal for fluid sealing, scrapers for contaminant removal, and a spacer for structural support. This segmentation allows each component to perform its specific function independently, with the scrapers protecting the seal from contaminants that would otherwise erode it during movement, thereby extending seal life while maintaining sealing reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The scrapers act as intermediary elements between the contaminants and the seal. By positioning the scrapers to contact the dynamic sealing surface first, they intercept and remove contaminates before the seal can interact with them, preventing erosion and extending the operational life of the seal while maintaining the sealing function

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If a scraper is added to prevent contaminate ingress to the dynamic sealing surface, then seal life is extended, but device complexity increases

Engineering Contradiction:
Improveseal lifeVSAvoidseal assembly complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The scraper and seal are merged into a single integrated seal assembly that moves together as one unit. The scraper is positioned within the same gland as the seal, and both components are loaded by the same spring mechanism. This merging allows the contaminant protection function to be added without requiring separate moving components, thereby extending seal life while minimizing the increase in device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The seal assembly is designed with multi-functionality: the primary seal provides fluid sealing, the scrapers provide contaminant removal, and the spacer provides structural support and positioning. By combining multiple functions into a single integrated assembly, the design achieves extended seal life through contaminant protection while avoiding the complexity of separate mechanisms for each function

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

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 assembly effectively prevents the ingress of contaminants, reducing maintenance needs and extending the useful life of the seals by ensuring the seals do not come into contact with particulates, thus maintaining a reliable dynamic sealing surface.

Implementation Method 1

The first seal is to provide a load to the first scraper to prevent the ingress of contaminate to a dynamic sealing surface

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The second seal is to provide a load to the second scraper

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2677219B1Seal assemblies for use with fluid valves
Publication Date: 2015.08.12 FISHER CONTROLS INT LLC
  • EP2677219B1 patent drawingFigure 1
  • EP2677219B1 patent drawingFigure 2
  • EP2677219B1 patent drawingFigure 3

AI summary

A valve trim assembly for use with fluid valves is disclosed comprising a cage, and a seal assembly to be positioned in a plug. Further the seal assembly comprises a first seal and a first scraper, wherein the first seal is to provide a load to the first scraper to prevent the ingress of contaminate to a dynamic sealing surface to be engaged by the first seal, a second seal and a second scraper, wherein the second seal is to provide a load to the second scraper, and a spacer between the first and second seals.