Digital Processor Sensor Loop Detector for Conveyor Rip Detection
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Solution Overview
Problem
Existing conveyor belt rip detection systems face challenges in noisy environments due to high electrical noise levels, sensitivity to environmental conditions, and the need to operate with different sensor loop configurations, as well as the cost and complexity of large capacitance automatic gain control circuits.
Innovation Solution
A digital processor-based sensor loop detector that generates excitation signals and analyzes feedback signals to select a frequency with minimum noise amplitude, uses fixed duration pulse strings to reduce capacitive cross-coupling, and operates effectively with both inverted and noninverted sensor loop configurations without large capacitance automatic gain control circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inductive coupling sensors are used in conveyor belts, then rip detection capability is provided, but electrical noise from capacitive cross-coupling significantly decreases signal-to-noise ratio and detection accuracy
Solution Approach 1:
The patent applies periodic excitation signals at specific frequencies to the sensor loops, using frequency-domain analysis to distinguish the periodic sensor response from random electrical noise. This periodic action allows the system to identify true rip events against the background of capacitive cross-coupling noise through spectral analysis.
Solution Approach 2:
The patent introduces an intermediary frequency domain analysis layer between the raw sensor signal and the rip detection decision. By transforming the time-domain signal into the frequency domain, the system can selectively amplify the frequency components corresponding to sensor loops while filtering out noise at other frequencies, thereby improving signal-to-noise ratio.
2Reliability
If large capacitance automatic gain control circuits are used to compensate for signal variation, then signal stability is improved, but device complexity and cost increase due to required shielding and filtering
Solution Approach 1:
The patent replaces the traditional automatic gain control circuit with a digital signal processing approach. Instead of using large capacitance circuits that require physical shielding and filtering, the system uses digital algorithms to compensate for signal variations, eliminating the need for complex analog circuitry and reducing both device complexity and cost.
Solution Approach 2:
The patent changes the approach from analog parameter adjustment (gain control through capacitance) to digital parameter processing. By converting the signal to digital form and applying software-based gain control, the system achieves signal stability without the physical constraints and complexity of large capacitance circuits.
3Reliability
If sensor loops are placed at intervals along the conveyor belt, then rip detection coverage is provided, but the system becomes sensitive to variations in signal coupling efficiency due to environmental conditions and distance
Solution Approach 1:
The patent implements dynamic signal processing that adapts to varying coupling conditions. The system continuously analyzes the received signal characteristics and adjusts processing parameters in real-time, allowing it to maintain reliable detection across different environmental conditions and distances between the conveyor belt and detector.
Solution Approach 2:
The patent employs feedback mechanisms where the detected signal strength and quality inform subsequent processing decisions. By monitoring the coupling efficiency and adjusting the detection thresholds and gain accordingly, the system maintains reliable operation despite variations in distance and environmental conditions.
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 enhances noise immunity, increases read range, reduces sensitivity to environmental variables, and eliminates the need for costly shielding and filtering, while maintaining accurate detection of conveyor belt damage in challenging conditions.
Implementation Method 1
Typically, an electrical energy source external to the belt is inductively coupled to a sensor loop in the belt
Implementation Method 2
A break in the conductive wire loop of the sensor may be detected by a remote transmitter/receiver (exciter/detector)
Data Source
AI summary
A digital processor for use in a conveyor belt rip detector, which provides excitation signals at a selected frequency to inverted and noninverted sensor loops on a conveyor belt and then detects corresponding received signals from the sensor loops. The digital processor then performs FFTs on the corresponding received signals to provide respective received signal frequency spectrums. Next magnitude and phase values of the selected frequency in the respective received signal frequency spectrums are used to determine a qualitative state of the sensor loops. The selected frequency has a lowest detected ambient noise level, and the magnitude value is a normalized magnitude value.