Toroidal Conductivity Sensor with Asymmetric Coils for Wider Range
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Solution Overview
Problem
Conductivity sensors face issues with signal linearization, limited sensing range, and bulky geometric size, particularly in toroidal sensors used for measuring conductivities in various industries.
Innovation Solution
The use of toroidal sensors with two differently sized toroids, a resistive element in parallel with the receiving toroid, and an internal conduction loop with a variable resistor element, along with in-situ calibration, to enhance signal resolution, broaden the sensing range, and reduce sensor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two toroids of the same permeance are used in conventional toroidal sensors, then the sensor structure is simple, but the sensing range is limited and signal resolution is insufficient
Solution Approach 1:
The patent applies asymmetry by using two toroids with different permeances (first toroid has higher permeance than second toroid). This asymmetric configuration allows each toroid to be optimized for different conductivity ranges, thereby expanding the overall sensing range while maintaining signal resolution through differential measurement.
Solution Approach 2:
The patent changes the permeance parameter of the two toroids to different values. By selecting toroids with different permeances, the sensor can measure a broader range of conductivities while maintaining adequate signal strength and resolution across the extended range.
2Force
If a larger-sized core is used for the driver toroid to improve magnetic field generation, then the magnetic field strength increases, but the sensor geometric size increases
Solution Approach 1:
The patent uses asymmetric toroid sizing where the first toroid (receiver) is larger than the second toroid (driver). This allows the receiver to have higher permeance for better signal detection while the driver remains compact, achieving strong magnetic field generation without proportionally increasing overall sensor volume.
Solution Approach 2:
The patent optimizes the driver toroid by adjusting its geometric dimensions (smaller size) while compensating through permeance selection and winding configuration, effectively decoupling magnetic field strength from direct proportionality to physical size.
3Measurement precision
If high permeance is used to cover lower conductive range, then signal strength is sufficient for low conductivity, but maximum detectable signal is reached too quickly limiting upper sensing range
Solution Approach 1:
The patent employs asymmetric permeance values for the two toroids, with the first toroid having higher permeance optimized for lower conductivity ranges and the second toroid having lower permeance suitable for higher conductivity ranges. This asymmetric configuration allows the sensor to cover both low and high conductivity ranges effectively.
Solution Approach 2:
The patent segments the sensing range by assigning different permeance characteristics to different toroids, with each toroid optimized for specific conductivity ranges. This segmentation allows the overall sensor system to cover a broader range than a single toroid could achieve alone.
4Measurement precision
If signal amplification is used to increase weak signal strength, then low conductivity signals become detectable, but noise is amplified along with the signal
Solution Approach 1:
The patent uses asymmetric permeance configuration to inherently optimize signal strength for low conductivity measurements without requiring external amplification. The higher permeance first toroid generates sufficient signal strength at low conductivity levels, avoiding the need for amplification that would also amplify noise.
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 achieves linearized sensing signals, broadens the sensing range, and reduces the geometric size of the sensor while maintaining accuracy and power efficiency, enabling calibration without external devices.
Implementation Method 1
When these toroidal sensors are immersed in a conductive fluid, the drive coil is electrically excited by an alternating current source and the drive coil generates a changing magnetic field. This changing magnetic field induces a current loop in the fluid to be tested.
Implementation Method 2
The current in the fluid induces a current in the receiver coil and that current is analyzed to measure the conductivity.
Data Source
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AI summary
A toroidal conductivity sensor having increased range and linearity. The size of the driving coil can be reduced in comparison to the receiving coil. An internal conduction loop is provided through both driving and receiving coils.