Clamp-On Ultrasonic Flow Sensor for Flexible Hoses
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Solution Overview
Problem
Existing non-contact flow measurement devices for fluids in flexible hoses, particularly those with diameters less than 12 mm, face challenges such as signal crosstalk and reduced measurement accuracy due to the separation of transmitter/receiver converters and environmental influences, and lack effectiveness in smaller hose sizes and varying fluid conditions like temperature changes.
Innovation Solution
A clamp-on sensor design with integrated decoupled piezo elements and a modular measuring channel that allows flexible hose insertion, featuring a compact housing with a hinged cover, temperature compensation, and shielded electronics to minimize crosstalk and enhance signal coupling, using composite ceramics and a time-to-digital converter for improved measurement stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clamp-on sensors with separated transmitter/receiver converters are used, then non-contact flow measurement is achieved, but signal crosstalk occurs on the connecting line between components
Solution Approach 1:
The patent integrates the transmitter and receiver converters into a single sensor unit that is clamped onto the hose. This merging of previously separated components eliminates the connecting line between them, thereby preventing signal crosstalk while maintaining non-contact flow measurement capability through ultrasonic transit time difference method.
Solution Approach 2:
The sensor is divided into functionally separate piezo elements (transmitters and receivers) that are spatially arranged on the housing surface, with each element having a defined acoustic coupling area. This segmentation allows independent optimization of each component's function while keeping them integrated in one unit, reducing interference between elements.
2Measurement precision
If composite ceramics with optimized width/thickness ratio are used, then transverse vibrations and directional effects are reduced, but device complexity increases
Solution Approach 1:
The patent specifies optimized geometric parameters for the piezo elements, particularly the width-to-thickness ratio, to minimize transverse vibrations and directional effects. By carefully selecting these physical dimensions, the sensor achieves improved measurement accuracy without requiring complex additional components or structures.
3Adaptability or versatility
If measuring channel is designed for small hose diameters (3.5 mm), then measurement capability for small hoses is achieved, but coupling surface area for sound signals is reduced
Solution Approach 1:
The patent arranges multiple piezo elements in a two-dimensional array on the housing surface, with each element having a defined acoustic coupling area. For small hoses, the elements are positioned to maximize the effective coupling surface within the constrained measuring channel dimensions, utilizing spatial optimization in multiple dimensions to compensate for the reduced overall size.
4Device complexity
If evaluation electronics are integrated without A/D converter, then device complexity is reduced, but signal processing capability is limited
Solution Approach 1:
The patent replaces complex A/D conversion electronics with an optimized analog evaluation circuit that directly processes the ultrasonic transit time difference signals. This analog signal processing approach maintains measurement precision while significantly reducing device complexity and component count, as the evaluation electronics are integrated into the sensor housing without requiring separate conversion stages.
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 precise non-contact flow measurement in flexible hoses with diameters as small as 3.5 mm, providing high information fidelity and resistance to environmental influences, while maintaining measurement stability across varying temperatures and viscosities.
Implementation Method 1
the sound-emitting and -receiving ceramics (piezo elements) are integrated in a design that is decoupled from the other components
Implementation Method 2
with the transit time difference method also being a known method here, with such a device to work. The ultrasonic signals being coupled in the direction of the liquid flow or counter to it
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The sensor (1) has a compact housing (3) with a fixable foldable cover, and a measuring channel (2) with a measuring cell. The channel extends over the entire width of housing and in which the to-be-detected flexible tube is inserted in the deformed state. The cell is arranged in the middle of the channel and is comprised of two pairs of diagonally opposite and acoustically decoupled integrated ceramics in the left and right sides of the cell. A structural space for a transmitter and a base plate is arranged at the downward direction of the cell.