Coriolis Flow Meter Four Bent Conduits Independent Oscillators
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Solution Overview
Problem
Existing Coriolis mass flow meters with mechanically coupled measuring tubes face high thermomechanical stresses due to complex structural designs, which can lead to significant mechanical stresses and interference between oscillators.
Innovation Solution
The design incorporates four measuring tubes forming two independent oscillators with distinct natural frequencies, each with its own actuator and sensor arrangements, allowing for mechanical independence and reduced stress through differential natural frequency excitation and detection, along with asymmetric flow resistance to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If measuring tubes are mechanically coupled and excited, then measurement function is achieved, but thermomechanical stresses and device complexity increase
Solution Approach 1:
The flow meter is divided into two independent oscillators, each with its own measuring tubes and actuator arrangement. This segmentation allows each oscillator to be excited and measured independently, reducing the complexity of mechanical coupling while maintaining the measurement function through separate Coriolis force detection in each oscillator.
Solution Approach 2:
Two separate flow measurement functions are merged into a single device housing, with both oscillators contributing to the overall measurement capability. The merging allows the device to achieve comprehensive flow measurement while keeping each oscillator's structure relatively simple and independent.
2Reliability
If measuring tubes are mechanically coupled and excited, then measurement function is achieved, but mechanical stresses in measuring tubes increase
Solution Approach 1:
By segmenting the measurement system into two independently excited oscillators, each with separate actuator arrangements, the mechanical stress concentration that would result from coupling all tubes together is avoided. Each oscillator experiences stress independently, reducing peak thermomechanical stresses in the measuring tubes.
3Adaptability or versatility
If two flow meters are integrated into single housing, then measurement capability is improved, but interference between oscillators occurs
Solution Approach 1:
Each oscillator is designed with distinct local characteristics, particularly different natural frequencies for their bending vibration modes. This local differentiation in vibrational characteristics allows the two oscillators to operate simultaneously in the same housing without significant interference, as their vibrational energies do not resonate at the same frequency.
Solution Approach 2:
The oscillators are designed to vibrate at different natural frequencies, creating a vibrational separation that minimizes mechanical interference. The first oscillator operates at frequency f11 while the second operates at frequency f12, where |f11 - f12| is at least 0.1 times the lower frequency, ensuring that the vibrational modes do not couple or interfere significantly.
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 thermomechanical and vibration-mechanical stresses on the measuring tubes, enables lighter and more material-efficient construction, and minimizes interference between oscillators, while also reducing overall flow resistance.
Implementation Method 1
the first oscillator has a bending vibration mode with a first mode natural frequency (f11), wherein the second oscillator has a bending vibration mode with a second mode natural frequency (f12)
Implementation Method 2
the first actuator arrangement is configured to excite a bending vibration mode between the two measuring tubes of the first oscillator
Implementation Method 3
the first sensor arrangement is configured to detect vibrations of the first oscillator, and wherein the second sensor arrangement is configured to detect vibrations of the second oscillator
Implementation Method 4
the first and the second oscillator are configured to exhibit deflections caused by Coriolis forces superimposed on the bending vibration modes (hereinafter referred to as 'Coriolis deflections') when the measuring tubes are permeated by a mass flow
Data Source
Figure 1a~1d
Figure 2
Figure 3a~3b
AI summary
The invention relates to a Coriolis mass flow measuring device (100), comprising four curved measuring tubes (110a, 110b, 110, 110dd), two actuator arrangements (140a, 140c), and two sensor arrangements (142a-1, 142a-2, 142c-1, 142c-2). All four curved measuring tubes (110a, 110b, 110c, 110d) are fluidically combined both on the inlet side and the outlet side by a collector (120), wherein on the inlet side and on the outlet side, the measuring tubes are in each case combined in pairs by node plates (132a, 132c, 134a, 134c) to form oscillators. The actuator arrangements (140a, 140c) are designed to respectively excite bending vibration useful modes between the two measuring tubes of an oscillator, wherein the first oscillator and the second oscillator are each provided with a bending vibration useful mode having a first or a second useful mode natural frequency (f-11,f12), wherein the amount of the difference between the useful mode natural frequencies of the two oscillators (|f-11-f12|) is at least 0.1-times, for example at least 0.2-times, and in particular at least 0.4-times the lower of the two useful mode natural frequencies. The sensor arrangement is designed to detect the vibrations of the oscillators.