Flexible Solid Plate for Stuffing Box Shaft Misalignment

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Solution Overview

Problem

Conventional stuffing boxes experience leakage due to misalignment and axial/radial movements of the shaft, requiring precise installation skills and leading to uneven packing material sequencing and gaps.

Innovation Solution

A solid plate made of flexible material with specific Shore A hardness, cavities, and locking projections is used to absorb axial and radial movements, ensuring proper contact and alignment without damaging the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stuffing boxes are used without a solid plate, then the structure is simpler, but leakage occurs due to axial and radial movements of the shaft creating gaps in the packing material

Engineering Contradiction:

Improvesealing performanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A solid plate made of flexible material is introduced as an intermediary component between the stuffing box and the shaft. This plate absorbs axial and radial movements of the shaft, preventing gaps from forming in the packing material and eliminating leakage paths, thereby resolving the sealing performance issue without requiring complex alignment mechanisms

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid plate is designed with specific material properties (flexible material with Shore A hardness between 25-90) that enable it to deform and absorb shaft movements. By changing the material parameters to be flexible rather than rigid, the plate can adapt to shaft movements while maintaining contact with the packing material, preventing leakage

Inventive Principle:

Principle #35Parameter changes

2Reliability

If precise alignment is required during installation to prevent shaft misalignment, then leakage is reduced, but installation difficulty and time increase

Engineering Contradiction:

Improvesealing performanceVSAvoidinstallation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The solid plate performs self-alignment by deforming to match the shaft position. The flexible material automatically adjusts to accommodate misalignment, eliminating the need for precise manual alignment during installation while maintaining effective sealing performance

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The solid plate is installed beforehand to cushion and absorb potential misalignment issues. By placing this flexible component between the rigid stuffing box and shaft, it preemptively compensates for alignment errors that would otherwise cause leakage, simplifying the installation process

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If rigid plates are used to prevent shaft movements, then alignment is maintained, but damage to the device may occur

Engineering Contradiction:

Improvealignment precisionVSAvoiddevice damage risk

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The plate material parameter is changed from rigid to flexible (Shore A hardness 25-90), enabling it to maintain alignment precision through elastic deformation rather than rigid constraint. This flexibility prevents stress concentration and potential damage to the shaft or stuffing box while maintaining positioning accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A flexible solid plate is used instead of a rigid one. The flexible material can deform to accommodate shaft movements and misalignments, maintaining contact and sealing pressure without transmitting damaging forces to the shaft or stuffing box components

Inventive Principle:

Principle #30Flexible shells and thin films

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 provides a maintenance-free, lubrication-free stuffing box assembly that effectively absorbs shaft movements, reducing leakage and extending wear life while being easy to install and repair.

Implementation Method 1

A solid plate made of flexible material with specific Shore A hardness, cavities, and locking projections is used to absorb axial and radial movements

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12595848B2Solid plate and stuffing box comprising the solid plate

Publication Date: 2026.04.07 HAARSLEV IND AS

AI summary

The present invention relates to a stuffing box assembly comprising a stuffing box and a solid plate, the solid plate may be placed at the shaft introducing end of the stuffing box, between the stuffing box and a surface, when the stuffing box assembly is mounted on to the surface, the solid plate may be on a first side provided with a pressure plate flange and on a second side be provided with a counter pressure plate flange, wherein the pressure plate flange and/or the counter pressure plate flange is provided with one or more locking projections pointing towards the solid plate.