Triple-axis magnetometer for tramp metal detection in noisy environments
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Solution Overview
Problem
Tramp metal inclusions in oil sand mining processes, particularly in screen-less slurry preparation towers, can damage roll crushers, leading to lengthy outages due to the inability to effectively detect and remove metal objects amidst significant background noise from industrial environments.
Innovation Solution
A system utilizing triple-axis magnetometers to detect changes in magnetic fields, allowing for the discrimination of metal objects within non-metallic materials, even in environments with significant background metal, by employing static or slowly changing magnetic fields and advanced signal processing to isolate detection signals from noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic pulse induction methods are used to detect metal objects, then strong signals can be generated to detect both ferrous and non-ferrous metals, but background noise from significant amounts of metal in industrial environments becomes a large component of the detected signal, making background subtraction less effective and the desired signal lost in the noise
Solution Approach 1:
The system uses periodic excitation at multiple frequencies to distinguish between stationary background metal and moving tramp metal. By applying periodic magnetic field excitations at different frequencies and analyzing the frequency-specific responses, the system can identify and isolate signals from moving metal objects against the stationary background noise.
Solution Approach 2:
The invention exploits the dynamic nature of tramp metal (moving) versus static background metal. The system detects changes in magnetic field responses over time and across multiple frequencies, identifying metal objects based on their movement-induced signal variations rather than their static presence.
2Productivity
If screen-less slurry preparation processes are used, then the process can operate without screening apparatus, but tramp metal cannot be removed prior to crushing, leading to damage or jamming of roll crushers and lengthy process outages
Solution Approach 1:
The system performs preliminary detection of tramp metal before the metal reaches the crusher rolls. By detecting metal objects in advance using magnetic field measurements and analyzing changes across multiple frequencies, the system can trigger removal actions before the tramp metal causes damage or jamming.
Solution Approach 2:
The system continuously monitors magnetic field responses and provides real-time feedback about the presence of metal objects. This feedback mechanism enables dynamic control and timely intervention to prevent crusher damage while maintaining continuous operation of the slurry preparation process.
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 effective detection and discrimination of metal objects, preventing damage to equipment and reducing process outages by accurately identifying metal inclusions in noisy industrial environments, allowing for real-time monitoring and intervention.
Implementation Method 1
at least one triple-axis magnetometer disposed adjacent a detection volume and adapted to detect a change in strength and/or direction of a magnetic field
Implementation Method 2
Both ferrous and non-ferrous metals can be discriminated. Typically this method first generates a large magnetic pulse, and then measures the decay of magnetic fields generated by currents induced in metal objects by the first pulse.
Data Source
AI summary
A system for detecting and discriminating a metal object in a bulk non-metallic material includes at least one triple-axis magnetometer adapted to detect a change of a magnetic field and output a signal including a detection signal representative of a metal object and a signal processing system adapted to detect the detection signal. The bulk non-metallic may be continuously moving through a detection volume, or may be placed in and removed from the detection volume as a batch.