Ultrasonic Flow Meter Variable Impedance Circuit Signal Symmetry
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Solution Overview
Problem
Existing ultrasonic flow meters face challenges in accurately measuring flow velocities and rates due to mismatches in transducer characteristics, which affect signal symmetry and lead to zero flow offset issues.
Innovation Solution
The ultrasonic flow meter incorporates a variable impedance circuit that adjusts impedance values based on upstream and downstream time signals, optimizing signal symmetry by matching transducer characteristics and minimizing time differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixed impedance circuits are used, then the device complexity is low, but the signal symmetry deteriorates due to transducer characteristic mismatches
Solution Approach 1:
The patent applies dynamics by making the impedance circuits adjustable rather than fixed. The control circuit dynamically adapts the impedance values based on detected signal characteristics to compensate for transducer mismatches, transforming a static system into a dynamic one that can optimize performance in real-time.
Solution Approach 2:
The patent changes the impedance parameter values dynamically. By varying the impedance of the first and second impedance circuits independently, the system optimizes signal symmetry for different operating conditions and transducer combinations, moving beyond fixed parameter designs.
2Manufacturing precision
If transducer characteristics are matched manually, then the manufacturing precision improves, but the ease of manufacture deteriorates due to complex calibration requirements
Solution Approach 1:
The system performs self-calibration by automatically detecting signal characteristics and adjusting impedance values without external intervention. The control circuit monitors signal quality and autonomously optimizes impedance matching, eliminating the need for complex manual calibration procedures during manufacturing.
Solution Approach 2:
The patent implements feedback mechanisms where the control circuit continuously monitors signal characteristics and adjusts impedance values accordingly. This closed-loop system automatically compensates for transducer mismatches, replacing complex manual matching procedures with automated feedback-based optimization.
3Measurement precision
If impedance values are adjusted to optimize signal symmetry, then the measurement precision improves, but the use of energy increases due to additional control operations
Solution Approach 1:
The system performs impedance adjustment periodically rather than continuously. The control circuit optimizes impedance values at specific intervals or when signal characteristics change significantly, reducing energy consumption compared to continuous adjustment while maintaining measurement precision.
Solution Approach 2:
The impedance adjustment is dynamic and adaptive, activating only when needed based on signal quality detection. The control circuit adjusts impedance values in response to detected signal characteristics, avoiding unnecessary energy consumption during stable operating conditions.
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 solution enhances signal symmetry, reduces zero flow offset, and simplifies calibration, while maintaining low current consumption and operating effectively in both time and frequency domains.
Implementation Method 1
an ultrasonic flow meter comprises a time-to-digital converter that measures a time-of-flight, ToF, of an ultrasonic signal between two points at which an ultrasonic source and an ultrasonic detector are located
Implementation Method 2
a first and a second impedance circuit comprising a variable impedance, a first terminal coupled to the first transducer via the first impedance circuit, a second terminal coupled to the second transducer via the second impedance circuit
Data Source
AI summary
In an embodiment an ultrasonic flow meter includes a first transducer and a second transducer, a first impedance circuit and a second impedance circuit, each of the first and second impedance circuits having a variable impedance, a first terminal coupled to the first transducer via the first impedance circuit, a second terminal coupled to the second transducer via the second impedance circuit, a signal generator with a signal output and a signal evaluation circuit with a signal input, wherein the signal output and the signal input are coupled to the first and second terminals, and wherein the signal evaluation circuit includes a time-to-digital converter and a first comparator that couples the signal input to a first input of the time-to-digital converter, and a control circuit that is coupled to the signal generator, the signal evaluation circuit and the variable impedance.