Inductive Level Sensor for Wear-Free Fluid Position Sensing

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Solution Overview

Problem

Existing level sensors used in process control systems for fluid management in tanks are prone to wear and long-term drift due to mechanical components and moving parts, leading to inaccurate fluid level control.

Innovation Solution

A level sensor system utilizing a lever with a conductive target and an inductive coil to generate a magnetic field, measuring feedback signatures to calculate the position of a sensing member, allowing for accurate and reliable positional sensing with minimal mechanical adjustments and easy calibration of process control parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If mechanical components and moving parts are used in level sensors, then the sensor can detect fluid level positions, but the sensor experiences wear and long-term drift leading to inaccurate measurements

Engineering Contradiction:

Improvefluid level measurement accuracyVSAvoidsensor stability over time

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical contact components with a magnetic field-based sensing system. An inductive coil generates a magnetic field that interacts with a conductive target attached to the float, eliminating the need for mechanical switches or contacts. This substitution removes wear-prone moving parts while maintaining position detection capability, directly resolving the contradiction between measurement precision and long-term reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the sensing coil and the conductive target. This magnetic field mediator transfers positional information without requiring direct mechanical contact, enabling accurate level measurement while eliminating the wear and drift associated with mechanical components.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If traditional mechanical switches are used to control valves, then the system can maintain fluid levels, but the mechanical components require frequent maintenance and calibration

Engineering Contradiction:

Improvefluid level control efficiencyVSAvoidmaintenance and calibration frequency

Core Design Contradiction:

ProductivityVSEase of repair

Solution Approach 1:

The patent replaces mechanical switches with an inductive sensing system that uses magnetic field interactions to detect float position and control valve operation. This eliminates mechanical wear in the switching mechanism, significantly reducing maintenance requirements and calibration frequency while maintaining efficient fluid level control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The inductive sensing system requires no manual calibration or adjustment during operation. The system automatically maintains accurate measurements through its non-contact magnetic field interaction, eliminating the need for periodic human intervention for maintenance or calibration of mechanical components.

Inventive Principle:

Principle #25Self-service

3Reliability

If non-contact magnetic field sensing is used, then mechanical wear is reduced, but the system requires complex signal processing to interpret feedback signatures

Engineering Contradiction:

Improvereduction of mechanical wearVSAvoidsignal processing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs feedback signatures obtained from the inductive coil's interaction with the conductive target to determine float position. The system processes the changes in magnetic field characteristics (feedback signatures) to accurately calculate position information, transforming a potentially complex measurement into a reliable position signal through systematic feedback analysis.

Inventive Principle:

Principle #23Feedback

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 and reliable fluid level control with reduced mechanical wear, quick parameter adjustments, and reduced manual intervention by using magnetic field measurements to determine the position of the sensing member, thereby improving the stability and efficiency of fluid management in tanks.

Implementation Method 1

an inductive coil to generate a magnetic field and measure feedback signatures associated with the target and the magnetic field

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11041748B2Level sensors having conductive target movement sensing

Publication Date: 2021.06.22 FISHER CONTROLS INT LLC

AI summary

Level sensors having conductive target movement sensing are disclosed. An example level sensor includes a lever operatively coupled to a sensing member, a target operatively coupled to the lever, where the target includes a conductor, an inductive coil to generate a magnetic field and measure feedback signatures associated with the target and the magnetic field, and a processor to calculate a position of the sensing member based on the feedback signatures.