Mechanical Face Seal Torque Sensing for Sliding Surface Wear

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Solution Overview

Problem

Existing mechanical seal assemblies face challenges in determining the wear condition of sliding surfaces, which can lead to damage and the need for premature replacement due to contact issues during operation.

Innovation Solution

A mechanical seal arrangement equipped with a torque measuring device that detects torque applied to the stationary seal ring, allowing for direct measurement of wear on the sliding surfaces through changes in torque levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wear determination is based on leakage across the sealing gap, then wear condition can be determined, but the method is indirect and less reliable

Engineering Contradiction:
Improvewear detection accuracyVSAvoidmeasurement method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces indirect leakage-based wear detection with direct torque measurement using a torque sensor. The torque sensor mechanically measures the actual torque applied to the stationary seal ring, providing direct and accurate wear information without relying on leakage indicators. This substitution of measurement principle directly improves measurement precision while maintaining relatively simple device complexity.

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

2Reliability

If torque measuring device is added to directly measure torque on stationary seal ring, then wear detection reliability is improved, but device complexity increases

Engineering Contradiction:
Improvewear detection reliabilityVSAvoidmechanical seal assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque sensor serves multiple functions: it measures torque to detect wear, monitors operational conditions, and provides data for predictive maintenance. By making the measurement device multi-functional, the patent justifies the added complexity through enhanced reliability and additional benefits, resolving the contradiction between reliability improvement and device complexity increase.

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

Solution Approach 2:

The torque sensor acts as an intermediary element between the sealing system and the monitoring system. It converts mechanical torque into measurable signals without interfering with the normal sealing operation. This intermediary approach allows reliable wear detection while minimizing the impact on the overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If seal rings are replaced based on leakage detection, then wear damage can be prevented, but replacement timing may be delayed leading to excessive wear

Engineering Contradiction:
Improveseal reliabilityVSAvoidtime for wear detection
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The torque sensor provides continuous real-time feedback on the actual torque applied to the stationary seal ring. This feedback mechanism allows for immediate detection of wear conditions and timely intervention, preventing excessive wear and seal failure. The continuous monitoring eliminates the time delay inherent in periodic leakage checks, directly addressing the time loss issue while maintaining high reliability.

Inventive Principle:
Principle #23Feedback

4Reliability

If contact between seal rings occurs during operation, then sealing is maintained, but wear damage occurs on sliding surfaces

Engineering Contradiction:
Improvesealing effectivenessVSAvoidwear damage to sliding surfaces
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The torque sensor provides continuous monitoring of contact torque between seal rings. When abnormal torque levels indicating excessive wear or damage are detected, the system can trigger alerts or shutdowns, preventing further wear damage while maintaining sealing effectiveness during normal operation. This feedback mechanism allows the system to benefit from necessary contact during startup and shutdown while protecting against harmful prolonged contact wear.

Inventive Principle:
Principle #23Feedback

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 quick and reliable detection of wear on the sliding surfaces, allowing for timely replacement of seal rings and preventing damage from excessive wear or contact issues.

Implementation Method 1

The sensor is designed to detect a change in the position of the measuring unit in the groove. The change in position of the measuring unit is a measure of the torque exerted on the stationary seal ring.

Methodology Applied
Scientific EffectPosition detection:

Implementation Method 2

a measuring unit (7), which is fixed to a housing (8) of the mechanical seal by a base and arranged with a free end in a groove formed in the outer circumference of the stationary seal ring

Methodology Applied
Scientific EffectTorque-induced displacement: Deformation

Data Source

PatentEP4396477B1Mechanical face seal assembly having a torque-measuring device, and method therefor
Publication Date: 2025.06.11 EAGLEBURGMANN GERMANY GMBH &CO KG
  • EP4396477B1 patent drawingFigure 1
  • EP4396477B1 patent drawingFigure 2
  • EP4396477B1 patent drawingFigure 3~4

AI summary

The invention relates to a mechanical face seal assembly, comprising: - a mechanical face seal (2), which has a rotating face seal ring (3) and a stationary face seal ring (4), which define a sealing gap (5) between their sliding faces (3a, 4a); and - a torque-measuring device (6), which is designed to sense a torque applied to the stationary face seal ring (4); wherein: the torque-measuring device (6) comprises a measuring unit (7) and a sensor (9); a foot (72) of the measuring unit (7) is fastened to a housing (8), and the measuring unit (7) has a free end (71), which protrudes in a groove (40) formed in an outer periphery of the stationary face seal ring (4); and the sensor (9) is designed to sense a position change of the measuring unit (7) in the groove (40).