Coriolis Mass Flow Transducer Vibration Isolation
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Solution Overview
Problem
Measuring transducers with a single measuring tube have lower sensitivity for mass flow rate measurements due to direct exposure to Coriolis forces and inefficient conversion of mechanical excitation power, leading to a lower signal-to-noise ratio and sensitivity dependent on medium density.
Innovation Solution
A measuring transducer design with a first and second pipe end, featuring a measuring tube with a predetermined wall thickness, a dummy carrier element structurally identical to the measuring tube, and an electrodynamic vibration exciter and sensor setup, where the vibration exciter is attached to the measuring tube or outer support element, and sensors are connected to the inner support element, optimizing the conversion of mechanical power into useful vibrations and reducing unwanted vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single measuring tube is used to reduce device complexity, then the structure is simpler, but the sensitivity for mass flow rate measurements decreases
Solution Approach 1:
The patent introduces a dummy carrier element that is structurally identical to the measuring tube but does not guide the medium. This copy allows the system to differentiate between useful vibrations (affecting both tubes) and Coriolis vibrations (affecting only the measuring tube), thereby improving measurement sensitivity without increasing the number of medium-guiding tubes
Solution Approach 2:
The dummy carrier element acts as an intermediary that receives the same mechanical excitation as the measuring tube but does not interact with the Coriolis forces. By comparing the vibrations of both elements, the system can isolate and measure the Coriolis effect more accurately, improving sensitivity while maintaining structural simplicity
2Power
If the vibration exciter is directly attached to the measuring tube, then the conversion of mechanical power to useful vibrations is more direct, but unwanted vibrations and noise increase
Solution Approach 1:
The patent introduces an inner support element as an intermediary between the vibration exciter and the measuring tube. This intermediary element allows efficient power transmission while providing mechanical isolation, reducing the transmission of unwanted vibrations to the measuring tube and improving the signal-to-noise ratio
Solution Approach 2:
The support structure is segmented into an outer support element and an inner support element, with the inner element serving as a dedicated vibration transmission path. This segmentation allows the system to separate useful vibration transmission from harmful vibration isolation, improving both power conversion efficiency and reducing noise
3Device complexity
If sensors are attached to the outer support element, then the detection structure is simpler, but the signal-to-noise ratio decreases
Solution Approach 1:
The inner support element serves as an intermediary mounting structure for the sensors, providing a stable reference frame that is isolated from external disturbances. This intermediary mounting improves the signal-to-noise ratio by reducing mechanical noise while maintaining sensor attachment functionality
Solution Approach 2:
The system uses both the measuring tube and dummy carrier element as identical structural copies, allowing sensors to detect differential vibrations between the two. This differential measurement approach, enabled by the copied structure, significantly improves the signal-to-noise ratio by canceling out common-mode noise
4Use of energy by moving object
If the measuring tube is made lighter to reduce energy consumption, then the excitation power required decreases, but the sensitivity to Coriolis forces decreases
Solution Approach 1:
The dummy carrier element provides a mass reference that is identical to the measuring tube. This copying of mass distribution allows the system to achieve better sensitivity by comparing the relative vibrations of two identical structures, effectively compensating for the reduced mass of lightweight tubes and maintaining high sensitivity with lower energy consumption
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
The design enhances the sensitivity and efficiency of mass flow rate measurements by ensuring that the mechanical excitation power is effectively converted into Coriolis forces, reducing the impact of medium density on sensitivity and improving the signal-to-noise ratio.
Implementation Method 1
a vibration exciter (E), having a first excitation component (E') fixed on the outside of the measuring tube (M) and a second excitation component (E'') attached to the outer support element (TE), which acts on the measuring tube (M) with electromagnetic forces to excite the useful vibrations of the measuring tube (M)
Implementation Method 2
The measuring tube (M) is designed to guide a flowing medium during operation and, during this time, to be allowed to perform useful vibrations around a static rest position in order to generate Coriolis forces
Implementation Method 3
a first vibration sensor (S1), having a first sensor component (S1') fixed on the outside of the measuring tube (M) and a second sensor component (S1'') attached to the inner support element (TS), which detects movements of the measuring tube (M) relative to the inner support element (TS) and converts the movements into a first vibration signal (S1s) representing vibrations of the measuring tube (M)
Data Source
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AI summary
Disclosed is a measurement transducer comprising a measurement tube (M), which has an inlet-side tube end (M+), an outlet-side tube end (M#), a tube wall with a pre-defined wall thickness, and a lumen, which extends between the first and second tube ends of the measurement tube and which is enclosed by said tube wall, further comprising a support element (TE), which is mechanically connected at one support end (TE+) to the tube end (M+) and at one support end (TE#) to the tube end (M#), and a support element (TS), which is laterally spaced from the measurement tube and which is mechanically coupled at one support end (TS+) to the support end (TE+) and at one support end (TS#) to the support end (TE#). The measurement tube of the measurement transducer is provided to guide a flowing medium in its lumen and to simultaneously be allowed to vibrate about a static rest position in order to generate Coriolis forces. The measurement transducer also comprises a vibration exciter (E) and at least one vibration sensor (S1; S2). The measurement transducer possesses a use mode, which has a resonance frequency and in which the measurement tube (M) can execute use vibrations around its static rest position at a use frequency that corresponds to the resonance frequency of the use mode, which use vibrations are suitable for generating Coriolis forces. The vibration exciter (E), of which one exciter component (E1') is arranged externally on the measurement tube (M) and one exciter component (E1") is arranged on the support element (TE), is also provided to induce said use vibrations in the measurement tube, and the vibration sensor, of which one sensor component (SV) is arranged externally on the measurement tube (M) and one sensor component (SV) is arranged on the support element (TS), is provided to detect movements of the measurement tube (M) relative to the support element (TS) and to transduce said movements into a vibration signal that represents vibrations of the measurement tube.