Ultrasonic Flowmeter Correction Using Viscosity and Sound Speed

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing ultrasonic flowmeters for fluid mixtures, such as water and antifreeze, face inaccuracies in determining flow velocity and concentration due to uncertainties in density, heat capacity, and mixing ratios, leading to approximately 2% concentration uncertainty.

Innovation Solution

A method and device that utilize measurement data to determine viscosity, density, and specific heat capacity, using defined relations between sound speed, temperature, and fluid properties, to calculate corrected flow velocity and concentration, incorporating Reynolds number and flow measurement corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasonic flowmeters are used to measure flow velocity in fluid mixtures, then flow measurement capability is provided, but measurement precision deteriorates due to uncertainties in density, heat capacity, and mixing ratios

Engineering Contradiction:

Improveflow velocity measurement accuracyVSAvoidconcentration determination accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the measurement parameters from direct concentration measurement to indirect measurement via viscosity and speed of sound. By measuring viscosity using a vibrating element and speed of sound using ultrasonic transducers, the system can determine fluid composition and flow characteristics with higher accuracy, resolving the contradiction between flow measurement capability and concentration determination accuracy

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces viscosity and speed of sound as intermediary parameters that link flow velocity measurement to concentration determination. These intermediary measurements provide reliable data about fluid composition without directly measuring concentration, thereby improving both flow velocity accuracy and concentration reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If reference tables are used to determine glycol concentration from speed of sound and temperature, then concentration can be estimated, but measurement precision is limited to approximately 2% uncertainty

Engineering Contradiction:

Improveconcentration determinationVSAvoidconcentration accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent adds viscosity measurement as an additional parameter to the existing speed of sound and temperature measurements. By combining multiple independent measurements (viscosity, speed of sound, temperature) rather than relying solely on reference tables from speed of sound and temperature, the system achieves concentration determination with accuracy better than the 2% uncertainty limit of traditional methods

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite measurement approach that combines multiple physical property measurements (viscosity, speed of sound, temperature) to determine concentration. This composite method is more accurate than any single measurement or traditional reference table lookup alone, overcoming the 2% precision limitation

Inventive Principle:

Principle #40Composite materials

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

Improves flow determination accuracy by reducing uncertainties in fluid mixture properties, enabling precise control of fluid flow and concentration in HVAC systems and immersion cooling applications.

Implementation Method 1

ultrasonic flowmeters use two ultrasonic transducers to measure transit times of ultrasonic waves along one or more measurement paths in a downstream and an upstream direction

Methodology Applied

Scientific EffectUltrasonic wave propagation: Ultrasound

Implementation Method 2

The flow velocity of the fluid vf is related to the transit times by the following equation: where t1 is the transit time in the downstream direction and t2 is the transit time in the upstream direction

Methodology Applied

Scientific EffectDoppler effect: Doppler Effect

Implementation Method 3

ultrasonic flowmeters are known which additionally have a temperature sensor configured to measure a temperature T of the fluid

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

ultrasonic flowmeters are known which measure a heat flow {dot over (Q)} emanating from a heat transporting fluid when passing through a consumer (e.g., a radiator)

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS20260092798A1Method and device for determining flow of a fluid

Publication Date: 2026.04.02 BELIMO HOLDING AG

AI summary

A method and device for determining the flow of a fluid in a channel includes receiving, in a processing unit of a flowmeter, measurement data of the fluid, the measurement data measured by a sensor system and including a measured flow velocity of the fluid, a measured temperature of the fluid, and a measured speed of sound in the fluid, determining, in the processing unit, a viscosity of the fluid, using the measurement data and a defined relation between speed of sound, viscosity, and temperature in the fluid, and calculating, in the processing unit, a corrected flow velocity of the fluid, using the measured flow velocity and the determined viscosity.