Vibronic Density Meter Compressibility Measurement

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Solution Overview

Problem

Current methods for determining the compressibility of fluids, particularly for calculating density at reference pressure, are not reliable due to limitations in measuring accuracy and precision, especially in gas-laden mixtures.

Innovation Solution

A method and device that utilize a vibronic density meter with a throttle to maintain different pressures, allowing for precise density and pressure measurements, which are used to calculate compressibility and correct for viscosity, enabling accurate determination of fluid compressibility and density under varying conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If density measurements are taken at different pressures to determine compressibility, then measurement precision is improved, but device complexity increases due to multiple pressure sensors and throttles

Engineering Contradiction:
Improvecompressibility measurement precisionVSAvoidmeasuring device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the pressure measurement process into distinct pressure points (first pressure at inlet, second pressure at outlet) using separate pressure sensors. This allows independent measurement of pressure values at different locations, enabling compressibility calculation while maintaining manageable device complexity through modular sensor placement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A throttle element is introduced as an intermediary component to create controlled pressure difference between measurement points. The throttle acts as a mediator that enables pressure variation without requiring complex pressure control systems, simplifying the overall device while achieving the needed pressure differential for accurate compressibility measurement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If viscosity effects are not corrected in density measurements, then measurement simplicity is maintained, but measurement precision deteriorates

Engineering Contradiction:
Improvedensity measurement precisionVSAvoidmeasurement procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system incorporates viscosity correction as a feedback mechanism where the measured viscosity value is used to adjust the density measurement. The evaluation unit applies correction factors based on viscosity data, continuously refining the density measurement accuracy without requiring additional physical measurement components, thus improving precision while adding minimal procedural complexity

Inventive Principle:
Principle #23Feedback

3Reliability

If multiple density and pressure measurements are taken, then reliability of compressibility determination is improved, but measurement time increases

Engineering Contradiction:
Improvecompressibility determination reliabilityVSAvoidmeasurement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs density and pressure measurements continuously as the fluid flows through the throttle element. Multiple measurement points are captured in a continuous flow process rather than requiring separate discrete measurements, maintaining reliable multi-point data collection while minimizing measurement time through simultaneous acquisition of pressure and density values at different locations

Inventive Principle:
Principle #20Continuity of useful action

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 allows for reliable and precise determination of fluid compressibility and density at reference pressures, improving measurement accuracy and enabling calculation of speed of sound and reference density values.

Implementation Method 1

a density meter with at least one oscillator, which has at least one oscillatable measuring tube, for guiding the medium

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

The resonant frequency for a low-viscosity fluid with a density of approximately 10^6 g/m^3 is, for example, in the order of 20 kHz

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

Driving a volume flow of the fluid by means of a pump through at least one measuring tube of a vibronic densimeter

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 4

the pressure drop across the densitometer (220) is calculated by forming the difference between the pressure measurements of the first pressure sensor (230a) and the second pressure sensor (230b)

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Implementation Method 5

determining a first pressure measurement value of the flowing fluid at the first pressure

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 6

the volume flow is a defined volume flow driven by a metering pump with a delivery accuracy of better than 1%, in particular better than 0.5%

Methodology Applied
Scientific EffectVolume flow:

Data Source

PatentEP3350567B1Method and measurement device for determining the compressibility of a flowing fluid
Publication Date: 2024.12.25 ENDRESS HAUSER FLOWTEC AG
  • EP3350567B1 patent drawingFigure 1
  • EP3350567B1 patent drawingFigure 2a~2b
  • EP3350567B1 patent drawingFigure 3

AI summary

A method (1) for determining the compressibility of a flowing fluid comprises the following steps: driving a volume flow of the fluid by means of a pump through at least one measuring tube of a vibronic density meter at a first pressure which is maintained by means of a throttle; determining a first density measurement value of the flowing fluid at the first pressure (10); determining a first pressure measurement value of the flowing fluid at the first pressure (10); driving a volume flow of the flowing fluid by means of a pump through a density meter at a second pressure which is maintained by means of a throttle; determining a second density measurement value of the fluid at the second pressure, which differs from the first pressure (20); determining a second pressure measurement value of the flowing fluid at the second pressure (20); determining the compressibility of the fluid based on the first density measurement value, the second density measurement value, the first pressure measurement value, and the second pressure measurement value, under the assumption that the composition of the fluid is unchanged between the detection of the first density measurement value and of the second density measurement value (30).