Vibration Transducer Fastening Element Design

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Solution Overview

Problem

Measuring transducers of the vibration type exhibit cross-sensitivity to pressure, leading to interference and reduced measuring accuracy, particularly due to rapid pressure changes and pulsating pressure fluctuations, which affect the precision of mass flow and density measurements.

Innovation Solution

The design incorporates a fastening element with a specific radial force distribution and minimal residual deformations, minimizing pressure-induced radial forces and deformations, and aligning the fastening element's axis of inertia with the measuring tube's axis of vibration to reduce interference effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional fastening elements are used to hold vibration sensor components on the measuring tube, then the device structure is simple and easy to manufacture, but cross-sensitivity to pressure increases and measuring accuracy deteriorates

Engineering Contradiction:
Improvemeasuring accuracyVSAvoidfastening element design
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The fastening element is designed with non-uniform wall thickness, creating locally differentiated structural properties. The varying wall thickness distributes radial forces unevenly along the circumferential direction, minimizing residual deformations at critical locations while maintaining overall structural integrity, thereby reducing pressure-induced interference with vibration measurements

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The fastening element employs asymmetric geometry with respect to the measuring tube circumference. By positioning the extension and varying wall thickness asymmetrically, the design creates a specific radial force distribution that minimizes deformations in the region where the vibration sensor is mounted, thus reducing cross-sensitivity to pressure changes

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If the fastening element is designed to minimize residual deformations, then measuring accuracy is maintained, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemeasuring accuracyVSAvoidfastening element fabrication
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The design utilizes controlled variations in wall thickness as a key geometric parameter to achieve the desired radial force distribution. By carefully selecting and optimizing the wall thickness profile, the fastening element minimizes residual deformations under pressure while remaining manufacturable with standard precision capabilities

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the fastening element aligns its axis of inertia with the measuring tube's vibration axis, then interference effects are reduced, but the fastening element design becomes more complex

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidfastening element configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fastening element features an asymmetric design with a single extension protruding from one side rather than symmetric extensions on opposite sides. This asymmetric configuration naturally aligns the axis of inertia with the measuring tube's vibration axis, minimizing interference effects while maintaining structural simplicity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The extension is positioned at a specific location on the fastening element circumference, creating local structural differentiation. This localized feature optimizes the moment of inertia distribution to align with the vibration axis, reducing interference with the vibration sensor's operation

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

This approach significantly reduces cross-sensitivity to pressure, maintaining high measuring accuracy by minimizing pressure-induced movements and deformations in the vibration sensors, thereby enhancing the reliability of mass flow and density measurements.

Implementation Method 1

a specific radial force distribution and minimal residual deformations, minimizing pressure-induced radial forces and deformations

Methodology Applied
Scientific EffectRadial force distribution: Mechanical Force

Implementation Method 2

at least one vibration sensor for generating at least one primary signal of the measuring transducer representing vibrations of the measuring tube

Methodology Applied
Scientific EffectVibration detection: Vibration

Implementation Method 3

measuring transducers of the vibration type also have an exciter arrangement which is activated during operation by an electrical driver signal generated by the aforementioned driver electronics and correspondingly conditioned, e.g. a regulated current, which excites the measuring tube by means of at least one during operation by a current electromechanical, esp.

Methodology Applied
Scientific EffectElectromechanical excitation: Electromagnetic Induction

Implementation Method 4

which induce reaction forces, for example Coriolis forces, in the flowing medium by means of a vibration-type measuring transducer

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Data Source

PatentEP2304393B1Vibration-type transducer
Publication Date: 2022.11.16 ENDRESS HAUSER FLOWTEC AG
  • EP2304393B1 patent drawingFigure 1
  • EP2304393B1 patent drawingFigure 2
  • EP2304393B1 patent drawingFigure 3

AI summary

The transducer converts a measurement tube (1) vibrating at least temporarily when in operation and having a wall thickness (s) and at least one, in particular electro-dynamic vibration sensor (17) for generation of at least one primary signal of the transducer representing a vibration of the measuring tube (10).  Furthermore, on the measuring tube in the transducer there is at least one, in particular metallic, attachment element spanning a line imagined along the perimeter thereof and having an overall width (B) for holding of one component of the vibration sensor, in particular a magnetic coil or a permanent magnet.  The attachment element of the invented transducer has an essentially square outer contour with a protrusion having a width (e) and protruding by a height (h) and used for holding of the component of the vibration sensor, said width is smaller than the overall width (B) of the attachment element.