Ultrasonic Flow Meter Using Propagation Time Differential for Instantaneous Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flow rate measuring devices struggle to accurately detect momentary changes in flow rates due to averaging flow velocities over long periods, which is inadequate for applications requiring rapid response, especially in household gas meters where pressure pulsation and temperature variations affect measurement precision.
Innovation Solution
A flow rate measuring device with a timing controller and time differential memory that measures propagation time differentials between forward and reverse ultrasonic wave signals, allowing for both accurate averaging of flow velocities and instantaneous flow rate estimation by thinning repeated unit measurement processes, enabling detection of momentary flow rate changes without increased power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If propagation time is measured with high time resolution to accurately detect flow velocity, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by repeating ultrasonic wave signal transmission M times and measuring propagation times at multiple points. Instead of continuous high-resolution measurement, the system performs periodic measurements at discrete time points (0, TA, 2TA, ..., (M-1)TA) and averages the results. This periodic sampling approach achieves the necessary measurement precision while significantly reducing power consumption compared to continuous high-resolution measurement.
2Measurement precision
If repeated measurements are performed to achieve necessary time resolution, then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing propagation time differences for various flow velocities in a lookup table before actual measurement. During measurement, instead of performing complex real-time calculations with M repeated measurements, the system simply retrieves the pre-computed values from the table based on the measured propagation times. This eliminates the need for time-consuming real-time computation while maintaining measurement precision.
3Stability of the object's composition
If flow velocity is averaged over long periods to eliminate pulsation effects, then measurement stability is improved, but response speed to momentary changes deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the measurement into two distinct parts: (1) averaging propagation times over M repeated measurements to eliminate pulsation effects and achieve stable flow velocity measurement, and (2) using the averaged values to calculate flow rate. This segmentation allows the system to achieve both stability through averaging and responsiveness by using the averaged flow velocity to detect momentary changes in flow rate, resolving the contradiction between stability and response speed.
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 device achieves accurate momentary flow rate detection while maintaining averaged flow rate precision, reducing power consumption and enhancing the security function of household gas meters by using propagation time differentials to estimate changes in flow rates.
Implementation Method 1
a first transducer 2 and a second transducer 3 placed in a fluid flow path in which a fluid passes through each for transmitting and receiving an ultrasonic wave signal, and a timing part for measuring a propagation time of the ultrasonic signal transmitted between the first transducer and the second transducer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Switching a transmitting and receiving direction of two transducers (2,3) in the forward and the reverse direction, a time differential memory part (17b) storing a propagation time differential every K times a unit measurement process being executed, the propagation time differential being a differential between a propagation time of the ultrasonic wave signal in a forward direction and in a reverse direction, a flow rate calculating part (15) calculating a flow rate of a passing fluid based on a lump sum of propagation times in both the forward and the reverse directions obtained at least every K times of a unit measurement process being executed, an estimating part (18) estimating a change in a momentary flow rate of the fluid based on the time differential obtained every K times of the unit measurement process being executed and storing thereof in a time differential memory part (17b), thus obtaining an accurate flow rate and detecting the change in the momentary flow rate.