Fill Level Detection Using Thermal Properties
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Solution Overview
Problem
Existing fill level detection technologies face limitations in sensitivity due to material constraints and are often limited to detecting electrically conductive substances, failing to accurately measure non-conductive media and handle variations in container tilt.
Innovation Solution
A device utilizing multiple spaced measuring points with a series circuit of resistors and p-n junctions, connected to a multiplexer and control device, which measures temperature-dependent forward voltages to determine the fill level based on thermal properties of the medium, allowing for accurate detection of various media including liquids and gases, and mitigating measurement errors from container tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional resistor elements or thermistors are used for fill level detection, then the device can detect liquid presence, but the sensitivity is limited by material constraints
Solution Approach 1:
The patent changes the detection parameter from electrical conductivity to thermal properties. By using a heating element and temperature sensor to detect thermal conductivity and heat capacity differences between media, the system achieves high sensitivity and can distinguish between various media types (liquid, gas, foam) without being limited by material constraints of traditional resistive sensors
Solution Approach 2:
The patent replaces traditional electrical resistance-based detection mechanisms with a thermal field-based detection system. Instead of measuring electrical properties that are limited by material characteristics, the system uses thermal energy transfer properties to detect fill level, enabling versatile detection across different media types with high sensitivity
2Measurement precision
If measuring poles are used to detect water level, then electrically conductive substances can be detected, but non-conductive media cannot be detected
Solution Approach 1:
The patent fundamentally changes the detection parameter from electrical conductivity to thermal conductivity and heat capacity. The heating element transfers thermal energy to the surrounding media, and the temperature sensor measures the thermal response. Since all media (conductive or non-conductive) have distinct thermal properties, the system can detect both liquid and non-conductive substances with high accuracy
Solution Approach 2:
The patent substitutes electrical field-based measurement (measuring poles) with thermal field-based measurement. This replacement enables detection of non-conductive media that cannot be detected by electrical methods, while maintaining accurate detection of conductive media through their characteristic thermal responses
3Reliability
If thermal detectors with heating elements are used, then liquid presence can be detected, but only binary detection (present/absent) is achieved without precise fill level measurement
Solution Approach 1:
The patent segments the detection system into multiple heating elements and temperature sensors positioned at different heights. By measuring the thermal response at multiple discrete locations along the container, the system can determine not only the presence of liquid but also the precise fill level, transitioning from binary detection to continuous measurement
Solution Approach 2:
The patent adds the spatial dimension to thermal detection by distributing sensors at different heights. This multi-level arrangement allows the system to measure fill level by identifying which sensors are in contact with liquid versus gas, providing precise quantitative measurement rather than simple presence/absence detection
4Measurement precision
If continuous monitoring is performed to ensure accurate fill level detection, then measurement precision is maintained, but energy consumption increases
Solution Approach 1:
The patent implements periodic measurement cycles where heating elements and sensors are activated in sequence rather than continuously. The system can be configured to perform measurements at appropriate intervals based on application requirements, maintaining measurement precision while significantly reducing energy consumption compared to continuous monitoring
Solution Approach 2:
The patent activates only the necessary subset of heating elements and sensors for each measurement cycle based on the current fill level state. This partial action approach ensures accurate detection by engaging only the relevant components, thereby reducing overall energy consumption while maintaining measurement precision
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 provides a reliable and sensitive method for detecting fill levels in containers, capable of distinguishing between different media based on thermal conductivity and heat capacity, reducing errors from fluid waves and ensuring accurate measurements across varying conditions.
Implementation Method 1
The different thermal properties of the medium are utilized in a thermal measuring principle
Implementation Method 2
determining the medium from the temperature-dependent forward voltages resulting from the different thermal properties of the medium
Implementation Method 3
thermal diodes are utilized in connection with the heating elements, in the case of which the temperature-dependent current flow of a p-n junction is utilized for the temperature detection
Data Source
AI summary
The invention relates to devices for detecting the fill level of media in containers.The devices are distinguished, in particular, by a simple and reliable detection of the fill level.For this purpose, multiple measuring points, each consisting of a series circuit of a resistor and a p-n junction, are spaced apart from one another. Each measuring point is connected, on the one hand, to an input of a multiplexer. On the other hand, the measuring points are connected to a reference potential. The output of the multiplexer is connected to a control device, wherein the control device isa control device periodically supplying a voltage to the measuring point connected to the control device via the multiplexer and measuring the voltage drop,a control device determining the medium from the temperature-dependent forward voltages resulting from the different thermal properties of the medium anda control device ascertaining the fill level from the consecutive measuring points.