Ultrasonic Flow Meter Composite Tube Design

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Solution Overview

Problem

Ultrasonic flow meters face challenges in combining the advantages of metal and polymer flow tubes while ensuring cost-efficiency, mechanical stability, and protection from water ingress and corrosion, particularly in larger diameters where metal flow tubes are used with liners, and polymer-based meters lack strength and are prone to water diffusion.

Innovation Solution

A flow meter design featuring a metal flow pipe with a polymer liner that provides mechanical stability and resistance to hydrolysis, where the liner is integrated with an interface for housing mounting, allowing for separate housing materials and fabrication methods, and using a combination of metals and polymers to optimize strength and water resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal flow tube is used, then mechanical strength and water-tightness are improved, but production cost increases and lead content may be present

Engineering Contradiction:
Improvemechanical strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The flow tube is constructed as a composite structure with an inner polymer layer providing chemical resistance and an outer metal layer providing mechanical strength. This composite design allows the use of less expensive materials overall while maintaining the required performance characteristics, avoiding the need for expensive solid metal flow tubes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The flow tube is divided into functional segments: an inner polymer layer for chemical resistance and corrosion protection, and an outer metal layer for mechanical strength and structural integrity. This segmentation allows each material to perform its optimal function while reducing overall cost compared to using solid metal throughout.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If a polymer flow tube is used, then production cost decreases, but mechanical strength and water-tightness deteriorate

Engineering Contradiction:
Improveproduction costVSAvoidmechanical strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The flow tube combines polymer and metal materials in a composite structure where the polymer provides chemical resistance and the metal provides mechanical strength. This allows the use of cost-effective polymer materials while achieving the required mechanical performance through the metal reinforcement layer.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different materials are applied to different regions of the flow tube structure: polymer for the inner surface requiring chemical resistance and metal for the outer structure requiring mechanical strength. This local differentiation of material properties optimizes both cost and performance.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If a polymer flow tube is used, then production cost decreases, but resistance to water diffusion deteriorates

Engineering Contradiction:
Improveproduction costVSAvoidwater diffusion
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The composite structure includes a metal outer layer that provides a barrier to water diffusion, protecting the polymer inner layer and the electronic components from moisture ingress. This combination maintains cost-effectiveness while solving the water diffusion problem inherent in pure polymer construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The metal layer acts as an intermediary barrier between the external environment (source of moisture) and the polymer flow tube interior (containing electronic components). This intermediate layer prevents water diffusion while allowing the cost-effective polymer material to be used for the flow-conducting interior.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Reliability

If a metal flow tube with liner is used, then corrosion resistance is improved, but production cost increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The flow tube uses a composite structure with polymer and metal layers where the polymer provides corrosion resistance to the fluid being measured and the metal provides mechanical strength. This reversed composite design (polymer inner layer, metal outer layer) achieves corrosion resistance at lower cost than traditional metal tubes with polymer liners.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Instead of using a metal tube with a polymer liner (traditional approach), the invention inverts the structure to use a polymer tube with a metal outer layer. This inversion reduces production cost while maintaining corrosion resistance, as the polymer is in direct contact with the fluid and the metal provides structural protection.

Inventive Principle:
Principle #13The other way round (Inversion)

5Device complexity

If transducers are mounted on the outer surface of a polymer flow tube, then sealing requirements are eliminated, but this is only practical for small diameters

Engineering Contradiction:
Improvesealing requirementsVSAvoidapplicable diameter range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The metal outer layer of the composite flow tube provides a suitable mounting surface for transducers in larger diameter applications, while the polymer inner layer maintains the flow characteristics. This composite structure enables outer-surface transducer mounting to be practical for larger diameters where it would otherwise be problematic with pure polymer tubes.

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

The solution enhances mechanical stability, reduces filler usage in the polymer liner, and provides improved protection against corrosion and water ingress, enabling cost-effective production and extended lifespan with enhanced measurement accuracy and durability.

Implementation Method 1

Polymers are open for water diffusion and water may diffuse through a polymer wall of the housing and may damage elements enclosed by the housing

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

Metal flow tubes have the advantage of being strong and water-tight

Methodology Applied
Scientific EffectMechanical strength:

Implementation Method 3

a liner of a first polymer-based material, extending along an inner surface of the flow pipe between the inlet and the outlet

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP3963292B1Flow tube and housing for a flow meter
Publication Date: 2024.11.27 KAMSTRUP
  • EP3963292B1 patent drawingFigure 1~2
  • EP3963292B1 patent drawingFigure 3~4
  • EP3963292B1 patent drawingFigure 5~6

AI summary

Flow meter for an ultrasonic flow meter, comprising a flow tube with a through-going opening for passage of a fluid between an inlet and an outlet, comprising: a flow pipe of a first material, such as metal, extending between the inlet and the outlet, a liner of a second material, such as a polymer- based material, extending along an inner surface of the flow pipe between the inlet and the outlet, a housing providing a compartment for transducers and metering electronics wherein the housing is connected to the liner, by being mounted on an interface being an integrated part of the liner.