TDR Cable for Grain Level Sensing in Hazardous Bins
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Solution Overview
Problem
Accurately measuring the volume of substances in storage units, such as grain bins, is challenging due to uneven surfaces and hazardous conditions, requiring a safe, efficient, and cost-effective solution that avoids the need for expensive scanning hardware.
Innovation Solution
A system utilizing time-domain reflectometry with a cable and control device to measure substance levels by generating a signal that is reflected back, allowing for calculation of the substance's amount based on the signal's delay, employing a cable with a non-circular cross-sectional shape and pair of conductors to minimize drag forces and improve sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual measurements are used to assess grain levels, then workers can directly observe and measure the substance, but it becomes dangerous due to hazardous atmospheres and potential avalanching effects
Solution Approach 1:
The patent replaces manual mechanical measurement with an automated sensing system that uses electromagnetic signals (capacitive or time-domain reflectometry) to measure grain levels remotely, eliminating the need for workers to enter hazardous environments while maintaining measurement accuracy
Solution Approach 2:
The patent introduces an intermediary sensing mechanism (probe or cable) that indirectly measures grain levels by detecting dielectric properties or signal reflections, allowing measurement without direct human contact with the hazardous substance
2Object-affected harmful factors
If single point measurements are used with technologies like bobs or radar, then grain levels can be measured without human interaction, but the measurement accuracy is insufficient due to uneven grain surfaces
Solution Approach 1:
The patent segments the measurement process into multiple measurement points along the cable length, allowing simultaneous measurement of grain levels at different locations to account for uneven surfaces and provide a more accurate overall assessment
Solution Approach 2:
The patent transitions from single-point measurement to distributed measurement along the spatial dimension of the cable, enabling measurement of grain level variations throughout the storage unit rather than at a single location
3Measurement precision
If multiple point measurement systems with 3D level scanners are used, then grain level variations can be captured, but expensive scanning hardware must be mounted on the grain bin
Solution Approach 1:
The patent uses a cable that serves multiple functions: it acts as both the sensing element for measurement and as the signal transmission medium, eliminating the need for separate scanning hardware and simplifying installation
Solution Approach 2:
The patent uses the existing cable infrastructure (which is already present in the storage unit for other purposes) as a copy of the measurement medium, avoiding the need to install dedicated expensive scanning equipment
4Object-affected harmful factors
If measurement systems are designed to avoid sparks, then safety is improved in flammable environments, but the choice of technology is limited
Solution Approach 1:
The patent uses inherently safe measurement technologies (capacitive sensing and TDR) that operate in an electrically inert manner, using low-voltage signals that cannot ignite flammable atmospheres, thereby maintaining safety while preserving measurement capability
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 accurate, real-time measurement of substance levels in storage units without human interaction, ensuring safety and reducing costs by eliminating the need for expensive scanning hardware, while effectively handling uneven surfaces and hazardous environments.
Implementation Method 1
the present disclosure describes a novel system for estimating the amount of a substance in a storage unit that employs transmission line theory and in particular time domain reflectometry
Implementation Method 2
a signal generator configured to generate a signal and apply the signal to the cable, the signal configured to be reflected at a level of the substance in the storage unit; a receiver configured to detect the reflection of the signal
Data Source
AI summary
A system for estimating a substance level in a storage unit is disclosed. In one embodiment, the system includes a cable and a control device. The control device sense pulses down the cable and based on the time of reflected pulses determines the level of substance in the storage unit.