Conductive Polymer Seal Assembly for Gradual Wear Detection

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Solution Overview

Problem

Existing sealing arrangements fail to provide continuous monitoring of sealing function status, leading to sudden detection of wear limit and immediate replacement needs, without allowing for gradual state changes detection.

Innovation Solution

A sealing arrangement comprising a ring-shaped sealing element made of polymeric material, with an electrically conductive and insulating component, where the conductive component is axially arranged and bonded to the insulating component, and a contact element is attached for capacitive monitoring, enabling continuous wear detection through capacitance measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-material sealing element is used, then the sealing function is simple and reliable, but continuous monitoring of sealing status is not possible

Engineering Contradiction:
Improvesealing functionVSAvoidsealing status information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The sealing element is divided into multiple functionally distinct sections: a first section made of electrically insulating material and a second section made of electrically conductive material. This segmentation allows the seal to simultaneously provide sealing function and enable electrical monitoring of wear status, resolving the contradiction between reliability and information loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element combines electrically insulating and electrically conductive materials in a single composite structure. This composite design enables both the sealing function (through the insulating material's friction and wear properties) and the monitoring function (through the conductive material's electrical properties), allowing continuous status monitoring without compromising sealing reliability.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If wear monitoring is implemented using electrical contact detection, then wear limit detection is possible, but gradual changes in condition cannot be detected

Engineering Contradiction:
Improvewear detectionVSAvoidgradual wear state information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces binary mechanical contact detection (wear limit or not) with continuous electrical capacitance measurement. The capacitance between the conductive section and machine element varies continuously with wear, enabling detection of gradual wear progression rather than just the final wear limit state.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The capacitive sensor provides continuous feedback on the wear state of the sealing element. By measuring capacitance changes in real-time, the system enables proactive maintenance decisions based on gradual wear progression rather than reactive replacement after wear limit is reached.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If conductive and insulating materials are joined together, then monitoring capability is enabled, but manufacturing complexity increases

Engineering Contradiction:
Improvemonitoring capabilityVSAvoidassembly process
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The conductive and insulating sections are merged into a single integrated sealing element that can be supplied as one pre-assembled component. This merging eliminates the need for complex on-site assembly of multiple separate components, reducing manufacturing complexity while maintaining monitoring capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing element is designed as a universal component that simultaneously performs sealing and monitoring functions. This multi-functionality reduces the total number of components needed and simplifies the assembly process, as the monitoring capability is built-in rather than added through separate devices.

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

4Measurement precision

If a contact element is attached to the sealing element, then capacitive monitoring is enabled, but the device complexity increases

Engineering Contradiction:
Improvewear monitoringVSAvoidsealing structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The contact element is merged with the sealing element to form an integrated structure. The conductive section of the sealing element itself serves as the capacitive sensor, eliminating the need for separate external monitoring devices and reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing element's conductive section serves dual purposes: maintaining the sealing function and acting as the capacitive sensor for wear monitoring. This self-service approach enables monitoring capability without adding external complexity, as the sealing element itself provides the sensing function.

Inventive Principle:
Principle #25Self-service

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

Enables permanent status monitoring of the sealing function, allowing for early detection of wear and improved sealing performance, while being cost-effective and easy to assemble.

Implementation Method 1

enabling continuous wear detection through capacitance measurement

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3717807B1Seal assembly
Publication Date: 2023.03.01 CARL FREUDENBERG KG
  • EP3717807B1 patent drawingFigure 1
  • EP3717807B1 patent drawingFigure 2
  • EP3717807B1 patent drawingFigure 3

AI summary

Seal arrangement (1) for sealing off a gap between a machine element (2) and a housing (3), comprising at least one sealing element (4), which is made at least partly of polymer material, wherein the sealing element (4) has an annular configuration, wherein the sealing element (4) has at least one first annular element (5) and at least one second annular element (6), wherein the first element (5) is electrically conductive and the second element (6) is electrically insulating, wherein the first element (5) is spaced axially apart from the second element (6).