Ultrasonic Flow Meter Self-Calibration via Bidirectional Signal Switching
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Solution Overview
Problem
Conventional flow meter devices using ultrasonic signals to measure fluid flow rates face challenges in maintaining precision over time due to changes in offset values caused by aging and temperature variations, requiring inconvenient shutdowns to recalibrate, which disrupt fluid usage.
Innovation Solution
A flow meter device with a control unit that intermittently switches ultrasonic signal transmission and reception between two vibrators, measuring propagation times in both directions to calculate a correction amount based on a time difference, allowing for continuous operation and precise flow rate measurement without interrupting fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the offset value is measured in a no-flow state using a shut-off valve, then the measurement precision is improved, but the fluid usage is interrupted and convenience deteriorates
Solution Approach 1:
The patent enables continuous flow measurement without interrupting fluid usage. The control unit continuously or intermittently switches between transmitting and receiving vibrators to measure propagation times in both directions, allowing offset value updates while the fluid continues to flow through the conduit, thus maintaining continuous useful action
Solution Approach 2:
The control unit intermittently switches the transmitting and receiving vibrators at predetermined intervals to perform offset value measurements. This periodic switching allows the system to capture propagation time data at regular intervals without requiring continuous shutdown, balancing measurement needs with operational continuity
2Device complexity
If the offset value is measured only at factory settings or installation, then the device complexity is reduced, but the reliability deteriorates due to aging effects
Solution Approach 1:
The system implements feedback by continuously or periodically measuring propagation times in both directions and automatically calculating offset values. The control unit uses the measured propagation times to update the offset value stored in memory, creating a closed-loop system that adapts to aging effects without requiring manual intervention
Solution Approach 2:
The flow meter device performs self-calibration by automatically measuring offset values using its own vibrators and control unit. The system updates its own offset value stored in memory without requiring external calibration equipment or manual intervention, enabling the device to service itself and maintain accuracy over time
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 solution enables long-term precise flow rate measurement without interrupting fluid usage, reducing measurement errors and extending device lifespan by continuously updating correction values without requiring shutdowns.
Implementation Method 1
a first vibrator and a second vibrator, each of which is provided on the conduit and configured to transmit and receive an ultrasonic signal
Implementation Method 2
a timekeeper configured to measure a propagation time of the ultrasonic signal
Data Source
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AI summary
A flow meter device includes: a first vibrator (2), a second vibrator (3), a control unit (100), a timekeeper (10), and an arithmetic operation unit (200). The arithmetic operation unit is configured to: determine whether or not a time difference between a propagation time in the forward direction and a propagation time in the reverse direction is less than a predetermined value; calculate a propagation time correction amount based on the time difference if it is determined that the time difference is less than the predetermined value; and calculate a flow rate of the fluid by using the propagation time correction amount.