Movable Sealing Disc Bonnet for Diaphragm Seal Integrity

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Solution Overview

Problem

Fluid valves with elastomeric diaphragms face damage due to uneven expansion and contraction caused by temperature and pressure fluctuations, leading to potential leakage and reduced sealing integrity, as existing bonnet designs fail to maintain a constant compressive load independent of clamping force and manufacturing tolerances.

Innovation Solution

A bonnet assembly with a movable sealing disc and biasing element that allows the sealing disc to float relative to the housing, providing a controlled, constant load to the diaphragm's peripheral edge, independent of fastener clamping force, enabling the diaphragm to expand and contract without buckling or deforming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the bonnet provides a fixed compressive load to the diaphragm peripheral edge, then the sealing integrity is improved, but the diaphragm may buckle or deform due to temperature and pressure fluctuations

Engineering Contradiction:
Improvesealing integrityVSAvoiddiaphragm structural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent introduces a movable sealing disc that can dynamically adjust its position within the bonnet housing along the central axis. This dynamic mechanism allows the sealing disc to move in response to diaphragm expansion and contraction caused by temperature and pressure changes, thereby maintaining a constant compressive load on the diaphragm peripheral edge without causing buckling or deformation. The biasing element provides the necessary dynamic force to keep the sealing disc in contact with the diaphragm while accommodating its dimensional changes.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the bonnet assembly is rigidly fixed to the valve body, then the manufacturing precision requirements are reduced, but the compressive load on the seal varies with clamping force

Engineering Contradiction:
Improvetolerance requirementsVSAvoidcompressive load consistency
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The patent introduces a biasing element as an intermediary component between the sealing disc and the bonnet housing. This biasing element (such as a spring) serves as a force mediator that provides a constant compressive load to the sealing disc independent of the clamping force applied to the bonnet assembly. The biasing element absorbs variations in clamping force and ensures that the seal receives a consistent compressive load, thereby decoupling the seal load from the overall assembly clamping force and reducing sensitivity to manufacturing tolerances.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the sealing disc is fixed relative to the housing, then the device complexity is reduced, but the seal cannot accommodate diaphragm expansion and contraction

Engineering Contradiction:
Improvebonnet assembly structureVSAvoidseal performance under thermal and pressure cycling
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements a movable sealing disc that can dynamically adjust its position within the bonnet housing along the central axis. This dynamic mechanism allows the sealing disc to move in response to diaphragm expansion and contraction caused by temperature and pressure changes, thereby maintaining a constant compressive load on the diaphragm peripheral edge without causing buckling or deformation. The biasing element provides the necessary dynamic force to keep the sealing disc in contact with the diaphragm while accommodating its dimensional changes.

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 prevents diaphragm damage and leakage by maintaining a constant compressive load, reducing the impact of temperature and pressure fluctuations, and allowing for greater manufacturing tolerances, thus enhancing the sealing integrity and reliability of fluid valves.

Implementation Method 1

A biasing element is disposed in the recessed opening between a flange of the sealing disc and the shoulder of the housing to provide a load to a seal to be disposed between the housing and the fluid device. The biasing element biases the sealing disc away from the housing and the biasing element enables the sealing disc to move within the recessed opening relative to the housing when the bonnet assembly is coupled to the fluid device.

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2619494B1Bonnet apparatus to provide live-loading to a seal
Publication Date: 2014.11.12 FISHER CONTROLS INT LLC
  • EP2619494B1 patent drawingFigure 1
  • EP2619494B1 patent drawingFigure 2A
  • EP2619494B1 patent drawingFigure 2B

AI summary

Bonnet apparatus to provide live- loading to a seal are described herein. An example bonnet assembly (202) includes a housing (224) having a recessed opening (230) to define a shoulder (232) and a sealing disc (242) disposed within the recessed opening. A biasing element (244) is disposed in the recessed opening between a flange (248) of the sealing disc and the shoulder of the housing to provide a load to a seal to be disposed between the housing and the fluid device. The biasing element biases the sealing disc away from the housing and the biasing element enables the sealing disc to move within the recessed opening relative to the housing when the bonnet assembly is coupled to the fluid device.