Fill Level Measurement in Foam-Layered Containers
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Solution Overview
Problem
Existing level measurement methods in containers with multiple layers, such as foam on top of a liquid, face challenges in accurately distinguishing between the medium and interference layers due to overlapping echoes and varying dielectric constants, leading to inaccurate fill level readings.
Innovation Solution
A method involving the classification of measurement pulses by calculating expected amplitudes for medium and interference layer pulses, using threshold evaluation and relative permittivity values to separate and correct for signal distortions, allowing for reliable fill level measurement even with inhomogeneous layers like foam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional evaluation algorithm is used to detect individual reflection signals, then the measurement process is simple, but it cannot handle situations with multiple interfaces such as foam layers merging with medium pulses
Solution Approach 1:
The patent segments the echo signal into multiple individual pulses through pulse separation. The evaluation algorithm identifies local extreme points (maxima and minima) in the signal curve and separates them into distinct pulses, each potentially corresponding to a different interface. This segmentation allows the system to handle multiple interfaces (liquid surface, foam layers) that would otherwise merge into an uninterpretable signal.
Solution Approach 2:
The patent introduces dynamic parameters to characterize the pulses, including amplitude, width, and position. By continuously analyzing these dynamic characteristics of separated pulses, the system can distinguish between different types of interfaces (liquid vs. foam) and accurately determine fill levels even when interfaces are close together or have varying properties.
2Measurement precision
If the bandwidth of the transmit pulse is increased to separate echo pulses from close boundary layers, then pulse separation improves, but electronic design requirements and sampling rates become more stringent
Solution Approach 1:
Instead of increasing the bandwidth beyond what is necessary, the patent applies a targeted approach by using a bandwidth that is sufficient to resolve the specific foam layer thicknesses encountered in practice. The pulse separation algorithm then compensates for limited bandwidth by intelligently analyzing the signal characteristics, achieving adequate pulse separation without excessive electronic complexity.
Solution Approach 2:
The patent replaces the need for high-bandwidth hardware with a sophisticated software-based pulse separation algorithm. Instead of relying on electronic bandwidth to separate pulses, the system uses digital signal processing to identify and separate pulses based on their temporal and amplitude characteristics, substituting computational complexity for hardware complexity.
3Adaptability or versatility
If a monoprobe is used for measurement, then the sensor can be used in hygiene applications with easy cleanability, but foam penetration into the probe increases measurement difficulty
Solution Approach 1:
The patent converts the harmful effect of foam penetration into a useful measurement signal. Instead of treating foam in the probe as a disturbance to be eliminated, the system detects the foam layer interface through the probe and uses pulse separation to distinguish foam-related reflections from liquid-related reflections. This allows the monoprobe to measure through foam layers rather than being blocked by them.
Solution Approach 2:
The patent changes the approach from trying to prevent foam penetration to accepting it and compensating through parameter analysis. By analyzing pulse amplitude, width, and position parameters, the system can distinguish between reflections from the liquid surface and reflections from foam layers within the probe, accurately determining the liquid fill level despite foam presence.
4Measurement precision
If multiple foam layers with varying dielectric constants are present, then the measurement situation becomes more complex, but accurate fill level determination is still required
Solution Approach 1:
The patent segments the complex multi-layer foam structure into individual measurable interfaces. Each foam layer and the liquid surface create distinct reflection pulses that are separated and analyzed individually. This segmentation transforms an intractable multi-layer problem into a series of simpler interface detection problems that can be solved through pulse-by-pulse analysis.
Solution Approach 2:
The patent uses dynamic parameter analysis to handle varying dielectric constants in different foam layers. By continuously monitoring pulse characteristics (amplitude, width, position) and comparing them against expected ranges for different material interfaces, the system can adaptively identify which pulses correspond to which interfaces, accurately determining fill levels despite variations in foam properties.
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
This approach enables precise measurement of fill levels in containers with multiple layers, including foam, by accurately identifying and separating pulses, thus correcting for signal distortions and providing reliable and accurate fill level data.
Implementation Method 1
a first electromagnetic signal is sent along a monoprobe into the container
Implementation Method 2
a signal curve of a signal reflected in the container is recorded
Implementation Method 3
different physical or chemical properties, such as an interface between two media
Data Source
Figure 1~2
Figure 3~4
Figure 5a~6b
AI summary
The method involves emitting an electromagnetic signal along a sensor arranged in a container, where a signal sequence of the signals reflecting in the container is recorded. A measuring pulse corresponding to a limiting surface to a medium and another measuring pulse corresponding to the disruptive layer are identified in the signal sequence. An expectation value of the amplitude of the former measuring pulse and an expected value of the amplitude of the latter measuring pulse are calculated. The former and the latter measuring pulses are identified based on the expected values. An independent claim is included for a sensor with a transmitter.