Ultrasonic Liquid Level Switch Using Wave Signal Differential
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Solution Overview
Problem
Existing liquid level switch systems installed externally are prone to instability, high misoperation rates, poor reliability, and require manual calibration due to environmental and material-specific variations, leading to increased workload and reduced efficiency.
Innovation Solution
A liquid level switch system comprising a transmitting probe with a piezoelectric plate and inclined block, and a receiving probe, which transmit and receive ultrasonic signals with different refraction angles to determine the liquid level based on signal strength differences, eliminating the need for separate calibration and improving reliability by using the same probe for both measurement and calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-contact ultrasonic probe is installed externally on the tank wall to measure liquid level, then the measurement can be performed without contact with the liquid, but the signal strength varies greatly due to factors like adhesive layer thickness, liquid temperature, and ambient temperature, leading to poor stability and reliability
Solution Approach 1:
The patent changes the physical parameters of ultrasonic wave propagation by generating both longitudinal waves and transverse waves with different refraction angles through the tank wall. This allows the system to measure liquid level based on signal strength differences between the two wave types, which compensates for environmental variations and improves measurement stability.
2Measurement precision
If separate calibration and measurement probes are used, then the liquid level can be determined through signal strength ratio, but the probes are separately influenced by environmental factors causing random drift and reduced reliability
Solution Approach 1:
The patent merges the calibration and measurement functions into a single probe system. By using one probe to generate both longitudinal and transverse waves and another probe to receive both wave types, the system eliminates the random drift problem caused by separate probes being differently influenced by environmental factors like temperature and time.
Solution Approach 2:
The system uses feedback by continuously monitoring the signal strength differences between longitudinal and transverse waves. The main unit processes these differential signals to dynamically determine liquid level, compensating for environmental variations through continuous comparison rather than relying on fixed calibration values.
3Adaptability or versatility
If manual calibration and adjustment is performed for each tank body, then the measurement can be adapted to specific tank conditions, but the workload increases and efficiency decreases
Solution Approach 1:
The system performs self-calibration by automatically utilizing the inherent differences in signal strength between longitudinal and transverse waves. The main unit processes the differential signals to determine liquid level without requiring manual calibration for each tank, thereby maintaining adaptability to different tank conditions while eliminating manual adjustment workload.
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 system enhances the reliability of liquid level measurement and alarming by stabilizing signal strength differences between longitudinal and transverse wave signals, reducing the impact of environmental factors and eliminating the need for manual calibration, thereby improving efficiency and accuracy.
Implementation Method 1
the transmitting probe includes a piezoelectric plate and an inclined block; the inclined block is installed on the outer wall of the tank body, the piezoelectric plate is located on an inclined plane of the inclined block
Implementation Method 2
the ultrasonic signal is transmitted into the tank wall to generate a longitudinal wave signal and a transverse wave signal with different refraction angles
Implementation Method 3
After the ultrasonic wave enters the tank wall, the ultrasonic wave will be reflected back and forth between the inner surface and the outer surface of the tank wall for many times to form a residual vibration signal
Implementation Method 4
the receiving probe is configured to send the detected longitudinal wave receiving signal and the detected transverse wave receiving signal to the main unit
Data Source
AI summary
Disclosed are a liquid level switch system and a liquid level measurement method. The liquid level switch system has a transmitting probe, a receiving probe and a main unit. The transmitting probe is located at a warning position on the outer wall of a tank body, the receiving probe is located on the outer wall of the tank body, and the transmitting probe and the receiving probe are respectively connected to the main unit by means of cables. A piezoelectric plate is placed on an inclined block to change the incident angle of an ultrasonic signal entering the tank wall so as to generate a longitudinal wave signal and a transverse wave signal, and the main unit judges, according to a signal strength difference value between a longitudinal wave receiving signal and a transverse wave receiving signal, whether the liquid level of the tank body reaches the warning position.