Air Duct Fault Detection Using Fan Motor Torque-Speed Monitoring

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Solution Overview

Problem

Existing methods for monitoring air flow in extractor hoods are complex and costly, often requiring special devices to detect filter saturation and faults, which can lead to increased maintenance and operational inefficiencies.

Innovation Solution

A method that detects operating parameters of the fan motor, specifically the quotient of torque and speed, to infer air volume flow changes, allowing for early detection of disturbances in the air flow duct without additional measurement technology, and issues differentiated warnings for the degree of fault.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If special measurement devices are used to detect filter saturation and air flow duct faults, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvefault detection precisionVSAvoidmeasurement device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The fan motor performs self-diagnosis by monitoring its own operating parameters (current, speed, torque). The control device evaluates these parameters to detect air flow duct faults, eliminating the need for separate measurement devices. The system uses its inherent operational data to identify blockages, leaks, or filter saturation conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The control device serves multiple functions: it controls fan motor operation and simultaneously monitors air flow duct conditions. By integrating fault detection capabilities into the existing control system, the patent eliminates the need for dedicated measurement devices while maintaining comprehensive monitoring functionality.

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

2Reliability

If continuous monitoring of air flow parameters is implemented, then reliability of fault detection is improved, but use of energy increases

Engineering Contradiction:
Improvefault detection reliabilityVSAvoidenergy consumption for monitoring
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control device continuously receives feedback from the fan motor's operating parameters and dynamically adjusts monitoring intensity. By evaluating current, speed, and torque variations in real-time, the system reliably detects faults while managing energy consumption through intelligent parameter evaluation rather than continuous high-power measurement.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical or electronic measurement devices with electrical parameter analysis. By monitoring electrical characteristics (current, power, torque) of the fan motor, the system achieves reliable fault detection through software-based evaluation rather than physical measurement instruments, reducing overall energy consumption.

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

3Productivity

If early detection of air flow duct faults is achieved, then productivity is improved through timely maintenance, but device complexity increases due to additional monitoring requirements

Engineering Contradiction:
Improvemaintenance efficiencyVSAvoidmonitoring system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control device performs preliminary detection of air flow duct faults by continuously evaluating fan motor operating parameters before actual blockages or failures occur. By identifying trends in current, speed, and torque variations, the system enables proactive maintenance scheduling, improving productivity through timely intervention while using only the existing control infrastructure.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2765359B1Method for monitoring an air flow in an air duct
Publication Date: 2019.03.27 DIEHL AKO STIFTUNG & CO KG
  • EP2765359B1 patent drawingFigure 1

AI summary

The method involves detecting an operating parameter or a change of the operating parameter of a fan motor (5), where an error is detected in an air flow channel, if the detected operating parameter or the detected change of the operating parameter exceeds a predetermined limit. A warning message is issued during detecting the error in the air flow channel. A degree of the error is detected in the air flow channel. An independent claim is included for an air flow conveying device with a control device and a display device.