Fill Level Measurement Using Echo Quality Filtering
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Solution Overview
Problem
Existing level measurement methods using the transit time principle face inaccuracies due to signal interference, leading to unreliable information and potential misidentification of echo positions, which can result in inaccurate fill level determination.
Innovation Solution
The method focuses on using only useful echoes with echo qualities exceeding a predetermined minimum, employing echo quality criteria such as peak shape, amplitude ratios, and temporal development to ensure reliable information is derived for accurate fill level determination, and utilizes additional methods when primary echoes are not identifiable or of poor quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If all detected echoes are used for fill level determination, then more data is available for measurement, but measurement accuracy decreases due to unreliable echoes and signal interference
Solution Approach 1:
The patent changes the parameter of echo selection from using all detected echoes to using only echoes that meet a quality criterion. The quality criterion is defined by comparing the amplitude of each echo to the amplitudes of adjacent echoes, selecting only those with sufficiently high relative amplitude. This parameter change filters out unreliable echoes while retaining sufficient data for accurate measurement.
2Loss of time
If signal processing is simplified to detect all echoes, then processing time is reduced, but echo position misidentification increases due to interference
Solution Approach 1:
The patent introduces a quality criterion parameter based on amplitude ratios between echoes and their neighbors. This additional parameter enables more reliable echo selection without requiring complex signal processing algorithms. The criterion can be evaluated efficiently alongside standard echo detection, minimizing time loss while significantly improving reliability.
3Reliability
If echo quality criteria are applied to filter echoes, then measurement reliability improves, but device complexity increases due to additional processing steps
Solution Approach 1:
The patent implements echo quality filtering by comparing amplitude parameters of echoes with their neighbors. This approach uses simple mathematical operations (amplitude comparison and ratio calculation) that can be integrated into existing signal processing pipelines without requiring complex additional hardware or algorithms, thus limiting the increase in device complexity.
Solution Approach 2:
The patent applies a quality criterion that may reject some echoes, potentially using fewer echoes than all detected ones. However, this partial action (selecting only quality echoes) is sufficient to achieve the desired reliability improvement without implementing more complex comprehensive processing solutions.
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 ensures more accurate and reliable fill level measurements by filtering out unreliable echoes and utilizing the highest quality echoes for determination, thereby improving measurement precision and accuracy.
Implementation Method 1
signals are sent into the container by means of a transmitting and receiving unit (11) and the signal components reflected back to the transmitting and receiving unit (11) by reflectors in the container are received as received signals after a transit time (t) dependent on the distance traveled on this path
Implementation Method 2
the signal components reflected back to the transmitting and receiving unit (11) by reflectors in the container
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The invention relates to a method for measuring a fill-level (L) of a filling material (1) in a container (3), by using a fill-level measuring instrument (5) operating in accordance with the delay principle, by means of which reliably accurate fill-level determination can be carried out. In said method, by means of a transmitting and receiving unit (11), transmitted signals (S) are transmitted to the container (3) and the proportions thereof reflected back at reflectors in the container to the transmitting and receiving unit (11) are received as received signals (R) after a delay dependent on the distance covered on said path. On the basis of the received signals (R), echo functions (A(t)) are derived, which reproduce the amplitudes (A) of the received signals (R) as a function of a position (t) corresponding to the associated delay, and useful echoes (E) of predefined useful echo types that are respectively contained in the echo functions (A(t)) and can be identified using predefined echo detection methods are determined, wherein each useful echo (E) is a local maximum, which can be traced back to a reflection at a reflector assigned to each useful echo type, in particular a filling material surface (15), a container base (17) or a stirrer (9) located in the container (3), for each useful echo (P), the echo quality (QE) of which is determined, wherein the echo quality (QE) is higher, the more peak-shaped the echo function (A(t)) is in the area of the respective useful echo (E) and the more isolated from other local maxima the respective useful echo (E) occurs in the echo function (A(t)), and the fill-level (12) is determined by taking the echo qualities (QE) of the useful echoes (E) into account.