Optoelectronic Fill Level Sensor Multi-Point Time-of-Flight
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Solution Overview
Problem
Existing optical methods for measuring the filling level of liquids in containers face challenges such as misalignment, wave formation, and interference from container geometry, especially with clear or cloudy liquids, leading to unreliable signal reception and accuracy issues.
Innovation Solution
An optoelectronic filling level sensor using a laser scanner or multiple one-dimensional light scanners that measure distances at multiple points, employing time-of-flight methods and evaluating direct and container reflections to calculate the filling level, with a calibration process to differentiate between reflections from the surface, walls, and bottom, and account for refractive index and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single light beam is used for measurement, then the device complexity is low, but the measurement reliability deteriorates due to misalignment and wave formation
Solution Approach 1:
The patent divides the measurement system into multiple independent light beams (at least two) that scan different measurement points on the container. Each beam provides independent measurement data, and the system evaluates multiple distance values to determine the filling level. This segmentation approach ensures that if one beam is affected by misalignment or wave formation, other beams can still provide valid measurements, thereby improving measurement reliability without requiring a single complex beam system.
Solution Approach 2:
The patent transitions from single-point measurement to multi-point measurement by scanning light beams across different spatial positions on the container. This dimensional expansion from one point to multiple points allows the system to capture the spatial distribution of the filling level and identify the representative value (e.g., lowest point) that accurately reflects the overall filling state, improving reliability while maintaining manageable device complexity.
2Measurement precision
If multiple measurement points are scanned, then the measurement precision improves, but the measurement time increases
Solution Approach 1:
The patent employs periodic scanning of light beams across multiple measurement points in a systematic sequence. The beams are directed to different positions (e.g., first to the lowest point, then to other points) in a repeating cycle. This periodic action allows the system to gather precise multi-point data while maintaining a structured measurement rhythm that optimizes the balance between precision and measurement time.
Solution Approach 2:
The system performs preliminary identification of the lowest point or representative measurement point before conducting full multi-point scanning. By pre-determining which points are most critical for accurate filling level assessment, the system can prioritize measurements at these locations, reducing the total number of measurements needed while maintaining high precision, thus minimizing measurement time.
3Measurement precision
If direct reflection is used for clear liquids, then the measurement accuracy improves, but the system becomes sensitive to alignment and surface conditions
Solution Approach 1:
The patent uses multiple light beams scanning different positions to obtain multiple distance measurements. By segmenting the measurement approach across multiple beams and positions, the system can identify consistent measurements that are less sensitive to local alignment issues or surface waves. The evaluation unit compares measurements from different beams to determine the most reliable value, reducing the impact of alignment sensitivity while maintaining accuracy for clear liquids.
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 robust, non-contact measurement system that accurately determines filling levels for clear liquids, is resistant to misalignment and wave formation, and maintains hygiene standards, offering reliable operation even with aggressive or abrasive media.
Implementation Method 1
based on a distance measurement using a time-of-flight method
Implementation Method 2
measuring the propagation time of light
Implementation Method 3
evaluating direct and container reflections to calculate the filling level
Data Source
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AI summary
An optoelectronic level sensor (12) for determining the level of a medium (12) in a container (14) is specified, wherein the level sensor (10) has at least one light transmitter (20) for emitting a transmitting light beam (18) in the direction of the medium (12) and at least one light receiver (30) for generating a received signal from light (28) reflected in the container (14) as well as an evaluation unit (30) which is configured to determine the respective distance of the level sensor (10) to several measuring points in the container (14) from the received signal using a time-of-flight method.The evaluation unit (30) is further designed to identify a direct reflection (36) at a surface (16) of the medium (12) and/or a container reflection at the container (14) by evaluating the distances at the measuring points and to determine the fill level based on the direct reflection (36) and/or the container reflection.