Vibration Transducer Spring Elements Frequency Separation
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Solution Overview
Problem
Measuring transducers with straight measuring tubes in Coriolis mass flow meters face inaccuracies due to undesired oscillations in the secondary plane of oscillation, which have similar resonance frequencies as the desired mode in the primary plane, leading to measurement inaccuracies and the need for overdimensioned amplifiers to handle high signal levels.
Innovation Solution
The implementation of two spring elements, affixed to the measuring tube and counteroscillator, spaced from the coupling zones and exciter mechanism, to create a significant frequency separation between the primary and secondary modes of oscillation, with the spring elements arranged to suppress both symmetric and asymmetric disturbances, thereby defining the oscillation axis and reducing external disturbance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spring elements are added to separate resonance frequencies, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Spring elements are introduced as intermediary components between the measuring tube and the surrounding structure. These spring elements act as mechanical filters that selectively dampen secondary plane oscillations while allowing primary plane oscillations to pass, thereby separating the resonance frequencies and improving measurement accuracy without requiring complex electronic filtering systems
Solution Approach 2:
The natural frequency of the measuring system is modified by adding spring elements that change the stiffness characteristics of the support structure. This parameter change shifts the resonance frequency of secondary plane oscillations away from the primary measurement frequency, enabling frequency-based separation of desired and unwanted oscillation modes
2Reliability
If overdimensioned amplifiers are used to handle high signal levels, then reliability is improved, but cost increases
Solution Approach 1:
The spring elements are installed in advance to suppress secondary plane oscillations before they can generate large disturbance signals. By preventing these oscillations at their source, the system avoids generating high signal levels that would require overdimensioned amplifiers, thus reducing component costs while maintaining reliable signal handling
Solution Approach 2:
The spring elements convert the potentially harmful secondary plane oscillations into a beneficial frequency separation effect. By deliberately introducing these spring elements, the system transforms what would be measurement-disturbing oscillations into a means of frequency discrimination, eliminating the need for expensive signal processing hardware
3Measurement precision
If traditional stiffening solutions are applied to suppress oscillations, then measurement precision is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of applying a single complex stiffening structure, the solution segments the oscillation control function into multiple simple spring elements distributed around the measuring tube. Each spring element provides localized support and frequency separation, and collectively they achieve the desired oscillation control without requiring complex manufacturing processes
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 solution effectively separates the resonance frequencies of the primary and secondary modes of oscillation, reducing measurement inaccuracies and the need for overdimensioned amplifiers, while being cost-effective and simpler to manufacture compared to traditional solutions.
Implementation Method 1
a first spring element and a second spring element, wherein each of the at least two spring elements is affixed to measuring tube and counteroscillator spaced from each of the two coupling zones as well as also from the exciter mechanism
Implementation Method 2
By means of the two spring elements, a lowest eigenfrequency of the first natural mode of oscillation is set smaller than a lowest eigenfrequency of the second natural mode of oscillation
Data Source
AI summary
A measuring transducer includes: a measuring tube vibrating at least at times and serving for conveying medium to be measured; a counteroscillator, which is affixed to the measuring tube on an inlet-side, to form a first coupling zone, and to the measuring tube on an outlet-side, to form a second coupling zone; an exciter mechanism for driving at least the measuring tube; as well as a sensor arrangement for registering oscillations at least of the measuring tube. During operation, the measuring tube executes, at least at times and/or at least in part, bending oscillations about an imaginary bending oscillation axis, which imaginarily connects the two coupling zones with one another. Additionally, at least a first spring element and a second spring element are included, with each of the at least two spring elements being affixed to the measuring tube and the counteroscillator spaced both from each of the two coupling zones as well as also from the exciter mechanism.