Reinforced Ultrasonic Flow Sensor Body for Dimensional Stability

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Solution Overview

Problem

Ultrasonic fluid flow sensors face accuracy issues due to size variations in the sensor body caused by temperature and pressure changes, particularly in plastic materials with low rigidity and high thermal expansion, leading to inaccurate measurements.

Innovation Solution

A fluid-flow sensor assembly with a rigid spiral wrap made of metal or carbon fiber around a thermoplastic tubular body, which restricts size variations by minimizing both radial and axial expansions, ensuring accurate measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a plastic body is used for the sensor housing, then manufacturing cost is reduced and chemical compatibility is improved, but the body undergoes size variations due to temperature and pressure changes

Engineering Contradiction:
Improvemanufacturing costVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent combines plastic material with a rigid structure (metal or carbon fiber reinforcement) to create a composite body. The plastic provides chemical compatibility and cost benefits, while the rigid reinforcement minimizes thermal expansion and maintains dimensional stability, resolving the contradiction between manufacturing cost and measurement precision.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a plastic body is used for the sensor housing, then material cost is reduced, but thermal expansion causes size variations in the body

Engineering Contradiction:
Improvematerial costVSAvoiddimensional stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent creates a composite structure where plastic material is combined with a rigid reinforcement layer (metal or carbon fiber). The plastic provides low cost and chemical compatibility, while the rigid reinforcement layer has low thermal expansion coefficients, compensating for the plastic's thermal expansion and maintaining dimensional stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the physical parameters of the body by adding a rigid structure that alters the thermal expansion characteristics. The rigid reinforcement reduces the overall thermal expansion coefficient of the composite body, minimizing size variations with temperature changes while maintaining the cost benefits of plastic material.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a rigid structure is added to the plastic body, then dimensional stability is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a thin rigid structure (sleeve or wrap) that conforms to the plastic body. This thin reinforcement layer provides dimensional stability and minimizes thermal expansion without significantly increasing structural complexity or device complexity, as it can be applied as a simple wrapping or lining rather than a complex integrated structure.

Inventive Principle:
Principle #30Flexible shells and thin films

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 effectively stabilizes the sensor body, maintaining measurement accuracy despite temperature and pressure changes, while allowing for cost-effective and chemically compatible plastic materials to be used, reducing maintenance costs and improving measurement reliability.

Implementation Method 1

These sensors are sensitive to variations in temperature and pressure within the sensor body. Further, factors such as variations in pressure and temperature in the measuring region can alter the diameter or length of the sensor body

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

A rigid structure, e.g., sleeve or wrap, is disposed about the body, and acts to restrict size variation of the body, such as elongation and/or expansion of the body, during use

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3568671B1Fluid-flow sensor assembly having reinforced sensor body
Publication Date: 2023.05.03 GEORG FISCHER SIGNET LLC
  • EP3568671B1 patent drawingFigure 1
  • EP3568671B1 patent drawingFigure 2
  • EP3568671B1 patent drawingFigure 3

AI summary

A fluid-flow sensor assembly is provided, comprising a body defining a measuring region for fluid flowing therethrough. A rigid structure is defined about the body to restrict size variation of the body during use. As a result, the rigid structure keeps the measuring section from altering in size, thus ensuring accurate measurement. In an exemplary embodiment, the body defines a ridge assembly that circumscribes the outer wall of the body, and a spiral wrap formed of rigid material is wrapped around the body.