Radar Level Gauge Waveguiding Structure with Periodic Impedance Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Radar level gauge systems face challenges in achieving high accuracy due to environmental conditions influencing propagation velocity, and existing reference reflectors either disturb the measurement or are too weak to be reliably determined, leading to trade-offs in measurement accuracy.
Innovation Solution
A waveguiding structure with periodically arranged reference impedance transitions that produce a strong, easily detectable reference signal without disturbing the surface echo, achieved by configuring the distance between transitions to correspond to half wavelengths within a specific frequency range, allowing for accurate determination of propagation velocity without interfering with filling level measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If reference reflectors are added to determine propagation velocity, then measurement accuracy is improved, but the reference reflectors create disturbance in their vicinity that influences filling level measurement accuracy
Solution Approach 1:
The waveguiding structure is designed with periodically arranged reference impedance transitions that create localized impedance changes at specific positions. These transitions are engineered to produce weak echo signals only at their respective locations, allowing propagation velocity determination without creating strong disturbances that would affect the overall filling level measurement accuracy.
Solution Approach 2:
Instead of using strong reference reflectors that create prominent echoes, the invention uses multiple weak reference impedance transitions distributed along the waveguiding structure. Each transition creates a weak echo copy of the transmitted signal, and these weak echoes are processed to determine propagation velocity without dominating the measurement signal.
2Reliability
If reference reflectors are made stronger to be easily detectable, then propagation velocity determination is improved, but the strong echoes disturb the filling level measurement
Solution Approach 1:
The reference signaling function is segmented into multiple distributed reference impedance transitions along the waveguiding structure. Each transition contributes a weak echo signal, and the collective processing of these segmented weak signals provides reliable propagation velocity determination without the strong echo disturbances that would result from a single strong reference reflector.
Solution Approach 2:
Multiple weak echo signals from the periodically arranged reference impedance transitions are merged and processed together to form a reliable reference signal for propagation velocity determination. This combining approach achieves the necessary signal strength for accurate measurement without creating local disturbances that would affect filling level measurement.
3Measurement precision
If the distance between reference impedance transitions is reduced to fit more transitions, then propagation velocity determination accuracy is improved, but power loss increases
Solution Approach 1:
The distance between reference impedance transitions is optimized to correspond to half wavelengths within a specific frequency range. This parameter change allows the weak echo signals from adjacent transitions to combine constructively, improving propagation velocity determination accuracy while minimizing the number of transitions needed and thereby reducing total power loss.
Solution Approach 2:
The reference impedance transitions are arranged periodically along the waveguiding structure with spacing corresponding to half wavelengths. This periodic arrangement creates a resonant effect where the weak echo signals from each transition combine constructively at the receiver, enhancing the reference signal strength without requiring excessive numbers of transitions and minimizing power loss.
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 high-accuracy filling level determination by providing a strong reference signal that is distinct from surface echoes, maintaining measurement accuracy even in long waveguiding structures, and improving the determination of propagation velocity with a narrow frequency range and low power loss.
Implementation Method 1
electromagnetic signals are guided towards and into the product by a waveguiding structure, such as a probe or a still pipe
Implementation Method 2
reference impedance transitions that each result in a very weak echo signal, but together result in a strong reflected signal
Implementation Method 3
the distance to the surface of the product is generally determined based on the time between transmission of an electromagnetic signal and reception of the reflection thereof
Implementation Method 4
periodically arranged reference impedance transitions that each result in a very weak echo signal, but together result in a strong reflected signal in a narrow frequency range
Data Source
Figure 1a~1b
Figure 1c
Figure 2a~2b
AI summary
A radar level gauge system, for determining a filling level of a product contained in a tank, said radar level gauge system comprising: a transceiver for generating, transmitting and receiving electromagnetic signals within a frequency range; a waveguiding structure arranged to extend into said product contained in the tank and to guide a transmitted signal from said transceiver towards a surface of said product and to guide echo signals resulting from reflections at impedance transitions encountered by the transmitted electromagnetic signals, including a surface echo signal resulting from reflection at said surface, back to said transceiver; a plurality of reference impedance transitions provided substantially periodically along said waveguiding structure with a distance between adjacent reference impedance transitions that is selected such that signals resulting from reflection of said transmitted signal at each of said reference impedance transitions combine to form a reference signal having a frequency within said frequency range; and processing circuitry connected to said transceiver for determining a propagation velocity of said electromagnetic signals in a medium inside the tank above said surface of the product based on said frequency of said reference signal and said distance between adjacent reference impedance transitions, and determining said filling level based on said surface echo signal and said propagation velocity.