Dual Deflection Laser Scanner for Fill Level Measurement
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Solution Overview
Problem
Existing optical fill level measurement methods face challenges with non-perpendicular light incidence, wave formation, and interference from container geometry, leading to signal loss and inaccurate measurements, especially with cloudy or reflective liquids and surfaces.
Innovation Solution
A dual deflection unit laser scanner system that scans a transmitted light beam in a periodic manner, ensuring it strikes the surface perpendicularly or at an acute angle, allowing for robust distance measurement by evaluating multiple points and compensating for tilts and unevenness, and utilizing direct and container reflections to determine the fill level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-beam optical sensor is used to measure distance to the liquid surface, then the measurement can be simple, but the sensor loses the signal when light does not hit the surface perpendicularly or when the surface is uneven/wavy
Solution Approach 1:
The sensor divides the single measurement beam into multiple beams that are deflected at different angles. Instead of relying on one beam to hit the surface perpendicularly, the system uses several beams at various angles to ensure at least some beams can detect the surface even when it is uneven or wavy, thereby improving signal reception reliability
Solution Approach 2:
The patent introduces angular diversity by deflecting light beams at multiple different angles rather than using a single vertical beam. This multi-dimensional approach (combining multiple angles) ensures that even if the surface is tilted or wavy, at least some beams will reflect back to the sensor, solving the signal loss problem
2Reliability
If the measurement beam is widened greatly to average over a larger area, then partial signal reception is improved, but the measurement precision deteriorates
Solution Approach 1:
Instead of using one wide beam, the system segments the measurement into multiple narrower beams at different angles. Each beam maintains good directional precision for distance measurement, while the collection of multiple beams ensures reliable signal reception by averaging over different angular positions, thus achieving both precision and reliability
3Ease of operation
If radar sensors are used for non-contact measurement, then the measurement can be performed without touching the liquid, but the sensors are expensive, subject to interference from container geometry, and have dead zones at the edge of the container
Solution Approach 1:
The patent replaces radar (electromagnetic waves) with optical beams for non-contact measurement. Light-based measurement avoids the interference problems of radar with container geometry and eliminates dead zones at container edges, while maintaining the non-contact operation advantage. The optical system uses multiple deflected beams to ensure reliable measurement across the entire liquid surface
4Ease of operation
If ultrasonic sensors are used for non-contact measurement, then the measurement can be performed without touching the liquid, but the sensors are sensitive to environmental conditions such as temperature, humidity, pressure, noise and machine noise
Solution Approach 1:
The patent replaces ultrasonic (acoustic) waves with optical beams for non-contact measurement. Optical measurement is inherently immune to environmental factors like temperature, humidity, pressure, and noise that affect ultrasonic sensors. The light-based system maintains non-contact operation while eliminating sensitivity to harmful environmental factors
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
Enables precise and robust fill level measurement for various mediums, including cloudy liquids and reflective surfaces, reducing interference and ensuring accurate readings even under unfavorable conditions.
Implementation Method 1
the distance is deduced from its propagation time
Implementation Method 2
A type of light probe is also formed by a rotating line of image sensors
Implementation Method 3
the light sensor therefore does not receive the directed, specular reflection or direct reflection
Data Source
Figure 1~2
Figure 3~4b
Figure 5~6
AI summary
The sensor (10) has a light transmitter (12) that is provided for emitting a transmitted light beam (14) into a monitored zone (20). A movable deflecting unit (18a-18b) is provided for the periodic deflection of transmitted beam. A light receiver (26) is provided for generating a received signal at the measuring points in the zone which thrown back light (22). An evaluation unit (28) is adapted to determine respective distance to the measuring points from the received signal at the time of flight process, and the mutual distance value from the distances at several measuring points. The peripheral deflecting unit is provided for re-deflecting the periodically deflected transmitted light beam. An independent claim is included for method for determination of level of mediums in container.