Microwave Waveguide Fill Level Measurement in Flow Meters
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Solution Overview
Problem
Existing flow measurement technologies, such as magneto-inductive flowmeters, cannot accurately determine the continuous and quantitative fill level of liquids in pipelines, limiting the calculation of volume flow in partially filled pipelines.
Innovation Solution
A device using a measuring tube with electrically insulated conductors forming a microwave waveguide, coupled with an HF circuit and an operating-and-evaluating circuit to determine the fill level based on reflected microwave signals, allowing for the calculation of volume flow by combining fill level and flow velocity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If monitoring electrodes are used to detect fill level, then it can be determined whether the pipeline is essentially completely filled, but continuous quantitative determination of the degree of filling is not possible
Solution Approach 1:
The patent replaces the electrical contact-based monitoring electrode system with a microwave-based measurement system. The microwave signal propagates through the pipeline medium without requiring physical contact or electrical insulation, enabling continuous quantitative fill level determination. The system uses a microwave source, waveguide, and receiver to measure the dielectric properties and signal attenuation, which directly correlate with the fill level, thus achieving precise measurement without the limitations of electrical contact methods.
Solution Approach 2:
The patent utilizes changes in microwave signal parameters (amplitude, phase, attenuation) as the fill level changes. By measuring the attenuation and phase shift of the microwave signal as it propagates through different media (air vs. liquid), the system can continuously and quantitatively determine the degree of filling. This parameter-based approach enables precise fill level measurement without requiring complex electrode arrangements or contact with the medium.
2Measurement precision
If magneto-inductive flowmeters are used to measure flow velocity, then flow velocity can be measured in partially filled pipelines, but volume flow calculation cannot be performed without fill level information
Solution Approach 1:
The patent combines the magneto-inductive flow velocity measurement system with the microwave-based fill level measurement system into a single integrated measurement device. The microwave waveguide is integrated into the flowmeter housing, and both measurement functions (velocity and fill level) are processed together to calculate the volumetric flow rate. This merging eliminates the need for separate measurement systems and enables complete flow characterization in partially filled pipelines.
Solution Approach 2:
The microwave measurement system serves multiple functions: it determines the fill level, provides information about the medium's dielectric properties, and can detect the presence of different phases (liquid, gas, solid). This multi-functionality allows the system to handle various flow conditions and pipeline configurations, making the measurement system universally applicable to different measurement scenarios without requiring additional specialized equipment.
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 accurate and continuous measurement of fill level and volume flow in partially filled pipelines, enhancing the precision of flow measurement in applications like water/wastewater technology.
Implementation Method 1
the first conductor and the second conductor form a waveguide for microwaves
Implementation Method 2
an HF circuit for in-coupling a microwave signal into the waveguide and for receiving reflected microwave signals out-coupled from the waveguide
Implementation Method 3
which is adapted to determine fill level of liquid in the measuring tube based on received microwave signals
Data Source
AI summary
Disclosed is a device for measuring fill level of a liquid comprising: a measuring tube having a tube wall extending between first and second terminal openings and which surrounds a volume for guiding the liquid, wherein a tube axis extends between the two tube openings; a first conductor extending at least sectionally around the volume and is electrically insulated from the volume; a second conductor extending at least sectionally around the volume and is electrically insulated from the first conductor and from the volume, wherein the two conductors extend essentially in parallel with one another and form a waveguide for microwaves; an HF circuit for in-coupling a microwave signal into the waveguide and for receiving reflected microwave signals out-coupled from the waveguide; an operating and evaluating circuit for determining fill level of the liquid in the measuring tube based on received microwave signals.