Flowmeter Sensor Materials for Stable Ultrasonic Measurement Above 100°C

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Solution Overview

Problem

Conventional ultrasonic flowmeters experience a significant decrease in sensitivity and instability in high-temperature ranges exceeding 100°C due to the temperature-dependent characteristics of their materials, leading to inadequate measurement performance.

Innovation Solution

The flowmeter sensor employs a combination of materials with specific thermoacoustic properties, where the pipe is made of a first heat-resistant resin with negative thermoacoustic characteristics and the acoustic prism is made of a second heat-resistant resin with positive thermoacoustic characteristics, along with a coupling material layer, to maintain ultrasonic transmittance and sensitivity in high-temperature ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional materials are used in the flowmeter sensor, then the sensor can be manufactured with standard materials, but the sensitivity decreases significantly in high-temperature ranges exceeding 100°C due to negative thermoacoustic characteristics

Engineering Contradiction:

Improvemeasurement stabilityVSAvoidsensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the thermoacoustic parameter of the acoustic prism material from negative to positive characteristics. By selecting a material with positive thermoacoustic characteristics, the ultrasonic transmittance increases with temperature, compensating for the negative thermoacoustic effects in the pipe and coupling material, thereby maintaining measurement sensitivity and stability in high-temperature ranges exceeding 100°C

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite material system consisting of three distinct materials: a pipe material (with negative thermoacoustic characteristics), a coupling material (with negative thermoacoustic characteristics), and an acoustic prism material (with positive thermoacoustic characteristics). This composite structure allows the positive thermoacoustic effect of the acoustic prism to compensate for the negative effects of the other components, resolving the sensitivity degradation problem in high temperatures

Inventive Principle:

Principle #40Composite materials

2Device complexity

If the ultrasonic propagation path includes components with negative thermoacoustic characteristics, then the sensor structure can be simplified, but the overall ultrasonic transmittance decreases as temperature rises

Engineering Contradiction:

Improvesensor structureVSAvoidultrasonic transmittance

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful negative thermoacoustic characteristics into a beneficial effect by introducing a material with positive thermoacoustic characteristics. The acoustic prism's positive thermoacoustic behavior, which initially appears as an unusual property, becomes the key mechanism to compensate for and overcome the negative effects in other components, thereby improving overall ultrasonic transmittance in high-temperature environments

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

This configuration allows for stable flow velocity measurement across a wide temperature range, including high-temperature conditions exceeding 100°C, by mitigating the negative effects of thermoacoustic characteristics and ensuring accurate ultrasonic wave propagation.

Implementation Method 1

an acoustic prism having a bottom surface that is arranged in contact with the outer peripheral surface of the pipe and a front side inclination face that supports the ultrasonic transducer, and propagates ultrasonic waves from the ultrasonic transducer toward the fluid in the pipe

Methodology Applied

Scientific EffectUltrasonic wave propagation: Ultrasound

Implementation Method 2

the acoustic prism is made of a second heat-resistant resin having heat resistance in a temperature range of 90° C. to 200° C. and a positive thermoacoustic characteristics in which the ultrasonic transmittance increases as the temperature rises in such a temperature range

Methodology Applied

Scientific EffectThermoacoustic effect: Thermoacoustic Effect

Implementation Method 3

an ultrasonic transducer that generates ultrasonic waves

Methodology Applied

Scientific EffectUltrasonic transduction: Ultrasound

Data Source

PatentUS12392648B2Flowmeter sensor

Publication Date: 2025.08.19 HONDA ELECTRONICS CO LTD

AI summary

A flowmeter sensor can stably measure in a wide temperature range including one over 100° C. The flowmeter sensor includes an ultrasonic transducer, a pipe, and an acoustic prism. The acoustic prism has a bottom surface that is arranged in contact with the outer peripheral surface of the pipe and a front-side inclination surface that supports the ultrasonic transducer. The acoustic prism propagates ultrasonic waves from the ultrasonic transducer toward the fluid within the pipe. The pipe is made of a first heat-resistant resin having heat resistance in a temperature range of 90° C. to 200° C. and negative thermoacoustic characteristics in which the ultrasonic transmittance decreases as the temperature rises in such a temperature range. The acoustic prism is made of a second heat-resistant resin having heat resistance in the temperature range and positive thermoacoustic characteristics in which the ultrasonic transmittance increases as the temperature rises in such a temperature range.