Digital Travel Time Flow Meter Using Time Reversed Acoustics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ultrasonic travel time flow meters face challenges in accurately measuring average flow speed and flow profiles, especially in irregular flow conditions and open channels, where multiple propagation paths are required, and existing technologies are inefficient in power consumption and signal processing.
Innovation Solution
The use of a microcontroller-based ultrasonic flow meter that generates arbitrary pulse signals, employs digital signal processing, and incorporates a signal generating unit with a field programmable gate array (FPGA) to determine flow velocity by processing time-reversed digitized signals, reducing power consumption and improving signal resolution through pulse-width modulation and low-pass filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple propagation paths are used to measure flow in irregular flow profiles or open channels, then measurement accuracy is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent divides the flow measurement into multiple discrete propagation paths, each handled by separate sound transmitters and receivers. This segmentation allows independent processing of each path's signal, making the complex multi-path measurement manageable and enabling accurate flow profile determination through combination of individual path measurements.
Solution Approach 2:
The system performs preliminary calibration measurements to determine the impulse response of each propagation path before actual flow measurement. This preliminary action stores the characteristics of each path, which are then used during measurement to simplify the processing of flow data and improve accuracy without increasing real-time computational complexity.
2Use of energy by moving object
If digital signal processing with time-reversed digitized signals is used, then power consumption is reduced and signal resolution is improved, but device complexity increases
Solution Approach 1:
The patent applies time-reversal to the digitized received signals, processing them in reverse temporal order. This inversion technique focuses the signal energy back to the source location, improving signal resolution and enabling accurate flow measurement while using efficient digital processing that reduces overall power consumption compared to analog approaches.
Solution Approach 2:
The system replaces analog signal processing electronics with digital signal processing implemented in a microcontroller or FPGA. This substitution reduces power consumption and improves signal resolution through precise digital operations, though it increases the complexity of the processing unit. The patent justifies this by demonstrating the efficiency gains in power consumption and measurement accuracy.
3Measurement precision
If arbitrary pulse signals with high frequency are used, then signal resolution is improved, but power consumption and device complexity increase
Solution Approach 1:
The system uses periodic pulse signals with frequencies between 20 kHz and 2 MHz, corresponding to oscillation periods of 0.5 microseconds to higher frequencies. This periodic action provides sufficient signal resolution for accurate flow measurement while allowing the system to operate in discrete measurement cycles, reducing average power consumption compared to continuous high-frequency operation.
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 efficient and accurate measurement of flow speed and profiles with reduced power consumption, improved signal resolution, and the ability to handle complex flow conditions, making it suitable for various fluid conduits and gases.
Implementation Method 1
sound transducers, e.g. in the form of piezoelectric elements, also known as piezoelectric transducers, are used to generate and to receive a measuring signal
Implementation Method 2
An ultrasonic travel time flow meter evaluates the difference of propagation time of ultrasonic pulses propagating in and against flow direction
Implementation Method 3
Ultrasonic flow meters are either Doppler flow meters, which make use of the acoustic Doppler effect, or travel time flow meters
Implementation Method 4
improving signal resolution through pulse-width modulation and low-pass filtering
Implementation Method 5
improving signal resolution through pulse-width modulation and low-pass filtering
Data Source
AI summary
A microcontroller and a method are provided for determining a flow velocity with an electronic processing unit of an ultrasonic travel time flow meter with arbitrary waveform signals. The electronic processing unit has receiver and transmitter terminals, a signal processing unit and a signal generating unit that is configured to generate an oscillating electric output signal with a time dependent amplitude, wherein the time-dependent amplitude varies according to stored signal parameters.