Fill Level Measurement Using Echo Function Regression
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Solution Overview
Problem
Existing fill-level measuring devices using the travel time principle face challenges in reliably detecting an empty container, especially when the container floor is inclined or curved, leading to incorrect empty reports due to superimposed echoes from fill-level and container floor reflections, and issues with weak reflections from substances with low dielectric constants or foam formation.
Innovation Solution
A method that determines the empty echo position by analyzing echo functions over time, setting the empty echo position range based on container geometry and the installed position of the fill-level measuring device, and using regression lines to distinguish between fill-level and container floor echoes, ensuring accurate identification of an empty container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fill-level measuring device is mounted above the container and microwave signals are transmitted into the container, then fill level measurement is enabled, but in the case of empty container with inclined or curved floor, the container floor echo position varies and causes incorrect empty detection
Solution Approach 1:
The system performs preliminary characterization of the container geometry by detecting container floor echoes at multiple known fill levels during a learning phase. This preliminary action stores the relationship between fill level and container floor echo position, enabling accurate empty container detection later without being affected by inclined or curved floors.
Solution Approach 2:
The system uses feedback from detected echoes to continuously update and refine the echo function model. By comparing detected echoes with the stored echo function, the system can accurately identify fill-level echoes versus container floor echoes, even when the container floor geometry causes variable echo positions.
2Reliability
If the system evaluates a large range of distances to detect container floor echoes, then empty container detection coverage is improved, but fill-level echoes may be misidentified as container floor echoes causing false empty reports
Solution Approach 1:
The system applies local quality by creating a fill-level-specific echo function for each detected fill level. Instead of using a single generic evaluation range, the system tailors the echo detection criteria to the local characteristics of each fill level, comparing detected echoes against the expected echo pattern at that specific fill level.
Solution Approach 2:
The system changes the evaluation parameter from a fixed distance range to a dynamic echo function based on fill level. The echo function is generated specifically for each fill level detected, adapting the evaluation criteria to match the expected echo characteristics at that particular fill level.
3Productivity
If microwave signals are transmitted periodically into the container, then continuous monitoring is achieved, but weak reflections from substances with low dielectric constants or foam formation cause detection failures
Solution Approach 1:
The system performs preliminary characterization by building an echo function model during a learning phase before actual measurement begins. This preliminary action captures the container's geometric characteristics and expected echo patterns, enabling reliable detection even when fill substance reflections are weak.
Solution Approach 2:
The system uses feedback from the detected echo signals to compare against the pre-established echo function. This feedback mechanism enables the system to distinguish between genuine fill-level echoes and noise, even when the fill substance has low dielectric constant or forms foam that weakens reflections.
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 method provides reliable and accurate detection of an empty container by differentiating between fill-level and container floor echoes, reducing incorrect reports and improving measurement accuracy across various container geometries and fill substance properties.
Implementation Method 1
a fill-level measuring device working according to the travel time principle
Implementation Method 2
at least a part of the microwave signals transmitted into the container is reflected back to the fill-level measuring device via a reflection on a floor of the container
Implementation Method 3
echo functions are derived, which show amplitudes of the received signals as a function of a position corresponding to their travel time
Data Source
AI summary
A method for measuring a fill level of a fill substance in a container, in which, in an empty container, at least a part of the microwave signals transmitted into the container is reflected back via a reflection on a floor of the container. Microwave signals are transmitted into the container and their fractions reflected back to the fill-level measuring device. These are received as received signals. Echo functions are derived, which show amplitudes of the received signals as a function of a position corresponding to their travel time traveled in the container. A container floor echo is detected at a position, which lies in an earlier determined, both sides limited, empty echo position range, in which the container floor echo occurs in the case of empty container, at an empty echo position dependent on a shape of the container and an installed position of the fill-level measuring device.