Coriolis Flowmeter Input Circuit Phase Error Compensation

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Solution Overview

Problem

Coriolis mass flow meters face measurement inaccuracies due to insufficiently specified and drifting phase rotations in their input circuits, leading to zero-point errors and requiring complex calibrations, especially when using cheaper components with larger fluctuations in transmission behavior.

Innovation Solution

A Coriolis mass flow meter design that includes a reference signal generator to superimpose a reference signal on both sensor signals, allowing for the filtering and processing of auxiliary signals to determine and correct phase or transit time differences between the signals, thereby compensating for circuit-related errors and improving measurement accuracy without the need for complex calibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cheaper components with larger fluctuations in transmission behavior are used, then device cost is reduced, but measurement precision deteriorates due to insufficiently specified and drifting phase rotations

Engineering Contradiction:
Improvedevice costVSAvoidmeasurement precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the phase rotation values determined from reference signals are continuously used to correct the phase rotations of sensor signals. This closed-loop correction compensates for the drifting and unspecified phase rotations introduced by cheaper components, maintaining measurement precision without requiring expensive hardware.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces reference signals as an intermediary element to measure and characterize the transmission behavior of the input circuit. These reference signals serve as a mediator to determine phase rotation values that are then applied to correct sensor signals, allowing the system to compensate for component imperfections.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If complex calibrations are performed to reduce zero point errors, then measurement precision is improved, but device complexity increases

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

Solution Approach 1:

The patent performs preliminary measurement of phase rotation values using reference signals before actual mass flow measurement. This preliminary characterization of the input circuit's transmission behavior allows for pre-determination of correction values, eliminating the need for complex ongoing calibrations during normal operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses its own reference signals and internal processing capabilities to automatically determine and apply phase rotation corrections. The input circuit itself serves to measure its own transmission characteristics through the reference signals, and the processing unit automatically performs the correction without external intervention or complex calibration procedures.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If reference signals are superimposed on sensor signals to enable error compensation, then measurement precision is improved, but device complexity increases

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

Solution Approach 1:

The patent merges the reference signal with the sensor signal through superposition in the time domain. By combining these signals and using correlation analysis, the system extracts phase rotation information without requiring separate processing paths, thereby minimizing the increase in device complexity while achieving error compensation.

Inventive Principle:
Principle #5Merging (Combining)

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 permanently monitors the transmission behavior of the input circuit, eliminating the need for complex calibrations and ensuring high measurement accuracy even with cheaper components, by correcting for phase or transit time differences, thus enhancing the reliability and precision of mass flow measurements.

Implementation Method 1

Coriolis mass flow meters are used in industrial measurement technology to measure a mass flow of a medium in a pipeline section. The measuring tube is caused to vibrate. The vibration of the measuring tube is influenced by the medium flowing through it.

Methodology Applied
Scientific EffectCoriolis force: Coriolis Force

Implementation Method 2

The resulting oscillatory movement of the measuring tube is usually detected by two vibration sensors arranged on the measuring tube, the sensor signals of which are recorded and processed using an input circuit.

Methodology Applied
Scientific EffectVibration detection: Vibration

Implementation Method 3

A Coriolis mass flow meter design that includes a reference signal generator to superimpose a reference signal on both sensor signals, allowing for the filtering and processing of auxiliary signals to determine and correct phase or transit time differences

Methodology Applied
Scientific EffectSignal superposition:

Implementation Method 4

means which serve to filter out a processed first sensor signal and a processed first reference signal from the processed first auxiliary signal, means which serve to filter out a processed second sensor signal and a processed second reference signal from the processed second auxiliary signal

Methodology Applied
Scientific EffectSignal filtering: Filter (electronic)

Implementation Method 5

Means for determining a phase or transit time difference between the first processed reference signal and the second processed reference signal, Means for correcting the phase or transit time difference between the first and the second processed sensor signal based on the phase or transit time difference between the first and the second processed reference signal

Methodology Applied
Scientific EffectPhase difference measurement:

Data Source

PatentEP1886099B1Coriolis mass flowmeter and method for compensating for transmission errors in its input circuit
Publication Date: 2014.07.02 ENDRESS HAUSER FLOWTEC AG
  • EP1886099B1 patent drawingFigure 1
  • EP1886099B1 patent drawingFigure 2
  • EP1886099B1 patent drawingFigure 3~4

AI summary

The invention specifies a Coriolis mass flowmeter and method for compensating for transmission errors in its input circuit, with which a high degree of measurement accuracy can be achieved by the transmission errors in the input circuit having at least two input branches (35, 37) being detected using at least one reference signal (R), which passes through all the input branches (35, 37) at the same time.