Phased Array Ultrasonic Flow Meter with Thin Conduit Wall
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Solution Overview
Problem
Existing ultrasonic flow velocity measurement devices face challenges such as flow disturbance, contamination, and limited accuracy due to intrusive probes, complex and costly integration into pipe walls, and limitations in achieving off-center secant paths, especially with high flow velocities and inhomogeneous flow profiles.
Innovation Solution
A device with phased array ultrasonic transducer units that contact the outside of the conduit wall with a thin wall thickness, allowing for large secant angles and small path angles, enabling precise measurement without flow disturbance and contamination, and adjustable directional characteristics for varying fluid speeds and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intrusive ultrasonic probes are used to measure flow velocity, then measurement capability is improved, but flow disturbance and contamination occur
Solution Approach 1:
The patent uses the conduit wall as an intermediary medium to transmit ultrasonic waves from external transducers to the fluid. The transducers are mounted on the outside of the conduit, and the wall acts as a coupling medium, eliminating the need for intrusive probes while maintaining measurement capability. This resolves the contradiction by mediating between the measurement need and the flow integrity requirement.
2Object-affected harmful factors
If ultrasonic transducers are mounted on the outside of the conduit wall, then flow disturbance is avoided, but measurement accuracy decreases due to inability to achieve off-center secant paths
Solution Approach 1:
The patent employs a phased array of ultrasonic transducers with electronically controllable beam steering capability. By dynamically adjusting the phase and amplitude of each transducer element, the ultrasonic beam can be directed to create off-center secant paths through the fluid, enabling accurate measurement of asymmetric flow profiles while keeping transducers external to the conduit.
Solution Approach 2:
The patent changes the physical parameter of wall thickness in the contact area to less than half the wavelength of transverse waves in the wall material. This parameter change enables efficient ultrasonic transmission through the wall while maintaining the ability to achieve off-center measurement paths, thus improving measurement accuracy without causing flow disturbance.
3Measurement precision
If wall thickness in the contact area is reduced to enable ultrasonic transmission, then measurement accuracy is improved, but mechanical strength of the conduit may be compromised
Solution Approach 1:
The patent applies local quality modification by reducing the wall thickness only in the specific contact areas where ultrasonic transducers are mounted, while the rest of the conduit wall maintains its full thickness and structural integrity. This localized thinning enables efficient ultrasonic transmission without compromising the overall mechanical strength of the conduit.
4Measurement precision
If phased array transducers are used with electronic beam steering, then off-center secant paths are achieved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical positioning systems with electronic beam steering control. Instead of physically moving transducers or using mechanical gimbals to achieve different measurement paths, the system uses electronic phase and amplitude modulation of multiple fixed transducer elements to dynamically steer the ultrasonic beam, thereby achieving off-center secant paths with reduced mechanical complexity.
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 provides high measuring accuracy and universality across different fluids and conditions, with improved resistance to interference and drift effects, enabling precise flow velocity measurements without affecting the conduit's internal flow profile or mechanical stability.
Implementation Method 1
The ultrasonic transducers used to generate the ultrasound have an oscillating body, often a ceramic. With its help an electrical signal is converted into ultrasound and vice versa based for example on the piezoelectric effect.
Implementation Method 2
In a differential transit time method, a pair of ultrasonic transducers is mounted face to face on the outer circumference of the pipeline or conduit with a mutual offset in the longitudinal direction. These transducers alternately emit and receive ultrasonic signals transversely to the flow along the measuring path spanned between the ultrasonic transducers. The ultrasonic signals transported through the fluid are accelerated or decelerated by the flow, depending on the direction of travel. The resulting transit time difference is measured and accounted with geometrical quantities to an average flow velocity of the fluid.
Implementation Method 3
the conduit wall in the area of contact is formed with a wall thickness that is less than half the wavelength of the transverse wave of the ultrasound in the conduit wall
Data Source
AI summary
Flow velocity of a fluid is measured using a measuring sensor comprising a conduit with a conduit wall, and at least two ultrasonic transducer units (20, 22), each of which consists of an array of individual ultrasonic transducers (30-x, 32-x) and defining a measuring path (24) between them in the conduit (14). The ultrasonic transducer units emit ultrasonic signals and received ultrasonic signals are evaluated to determine the flow velocity. The individual ultrasonic transducers are driven with different phase, so that the ultrasonic transducer units provide a phased array. In order to achieve the most accurate measurement results possible, the ultrasonic transducer units contact the outside of the conduit wall (16), and the conduit wall (16) is formed in the area of the contact with a wall thickness (w) that is less than half the wavelength of the transverse wave (λRohr) of the ultrasound in the conduit wall.