Ultrasonic Flow Sensor with Lamella Support Arms

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Solution Overview

Problem

Existing liquid volume flow sensors with thick support arms cause significant flow resistance, turbulence, and hydraulic losses, making them unsuitable for use in pump housings and leading to inaccurate measurements due to improper installation and structural limitations.

Innovation Solution

Designing the support arms as thin, flow-straightening lamellae that shield the measurement section, with a high length-to-width ratio and minimal thickness, to minimize flow resistance and turbulence, while using piezo transducers for ultrasonic measurement and embedding electrical conductors for improved stability and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick support arms are used to hold the second housing part, then the structural stability is improved, but the flow resistance and turbulence increase significantly

Engineering Contradiction:
Improvestructural stabilityVSAvoidflow resistance
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The support arms are designed as thin lamellae instead of thick structures, using thin film principles to minimize flow obstruction while maintaining sufficient mechanical strength to hold the second housing part in position

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The support arms transition from thick strip-shaped structures to thin lamellar structures with specific dimensional parameters (length-to-width ratio of 10:1 to 40:1, thickness-to-width ratio of 5:1 to 20:1), changing the geometric parameters to reduce flow resistance while maintaining structural integrity

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If thick support arms are used, then the mounting stability is improved, but the measurement precision deteriorates due to turbulence

Engineering Contradiction:
Improvemounting stabilityVSAvoidflow measurement accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

Thin lamellar support arms create minimal disturbance to the flow field, allowing ultrasonic measurements to proceed with high precision while the lamellae still provide sufficient mounting stability for the sensors

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The support arms are designed with differentiated local properties - thin enough to minimize flow disturbance in the measurement zone, yet sufficiently stable structurally to maintain sensor positioning, achieving different quality requirements in different aspects

Inventive Principle:
Principle #3Local quality

3Device complexity

If conventional support arms are used, then the device complexity is reduced, but the flow conditioning capability is insufficient

Engineering Contradiction:
Improvesensor structure simplicityVSAvoidflow conditioning capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The lamellar support arms serve multiple functions simultaneously: they provide mechanical support for the second housing part, act as flow-conditioning elements that straighten and stabilize the flow, and minimize turbulence - combining structural and flow control functions in a single element

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

By optimizing the geometric parameters of the support arms (thin lamellar shape with specific length-to-width and thickness-to-width ratios), the structure achieves flow conditioning capability without adding separate flow straightening devices, maintaining simplicity while improving reliability

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the sensor is mounted using a screw thread, then the ease of installation is improved, but the measurement precision deteriorates due to undefined support arm position

Engineering Contradiction:
Improveinstallation easeVSAvoidflow measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The lamellar support arms have an asymmetric thin profile with a defined flow-facing side, allowing correct orientation to be visually identified during installation, preventing 90-degree rotation errors while maintaining ease of installation

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The support arms are designed with differentiated local properties - the thin lamellar shape provides flow-aligned orientation guidance, while the overall structure maintains ease of installation through simple mounting mechanisms

Inventive Principle:
Principle #3Local quality

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 reduces flow resistance, enhances measurement accuracy by shielding the measuring section from turbulence, and allows for precise installation in pump housings without additional flow conditioning, ensuring accurate flow velocity measurement with minimal signal degradation.

Implementation Method 1

a first ultrasonic sensor (11) is received in a first housing part (2), a second ultrasonic sensor (12) is received in a second housing part (3), wherein the two ultrasonic sensors (11, 12) are aligned (face-to-face) opposite each other, with the free space (6) between them

Methodology Applied
Scientific EffectUltrasonic wave propagation: Ultrasound

Implementation Method 2

Piezoelectric transducers, as known in the prior art, can be used as ultrasonic sensors

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2944926B1Fluid volume flow sensor
Publication Date: 2021.01.06 WILO SE
  • EP2944926B1 patent drawingFigure 1~3
  • EP2944926B1 patent drawingFigure 4~5
  • EP2944926B1 patent drawingFigure 6~7

AI summary

The invention relates to a volumetric flow sensor (1) for measuring the velocity of a main flow of liquid in a pipe section (25), in particular in a nozzle channel (25) of a pump housing (26), comprising a first housing part (2) connected to a mounting base (20) in which a first ultrasonic sensor (11) is received, a second housing part (3) in which a second ultrasonic sensor (12) is received, and two opposing support arms (7, 8) extending away from the first housing part (2) on which the second housing part (3) is held. The second housing part (3) is positioned at a distance from the first housing part (2), forming a measuring section (5) through which the liquid can flow, and the two ultrasonic sensors (11, 12) are aligned with each other.The two support arms (7) are each designed in the form of a flow-correcting lamella (7) that limits the measuring section (5) on one side, so that the measuring section (5) is shielded between the two support arms (7, 8).